PERSPECTIVES: BUILDING A MICRO MAGIC

PERSPECTIVES: BUILDING A MICRO MAGIC

(A Sudoku adventure in RC boat building)
by: Wm. Brown, Yeoman
Pima Micro Yacht Club,
Tucson, AZ

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Introduction

Producing a completed Micro Magic Radio Controlled model sailboat
can challenge the mind, patience, and creative talents of an otherwise relaxed and rational individual. The challenge comes from several directions. The finished product, however, is an extremely weight conscious and very finely tuned international racing machine. Being among the lightest of the competitive RC sailboats, the demand for
effective consolidation and distribution of weight, and, effective use of sails is critical. If these considerations aren’t enough, the kit presents itself with its own set of challenges.

Having built three Solings (10 Lbs) and two Victorias (5 lbs), I personally found the Micro Magic (2 lbs) the biggest and most rewarding challenge. Yes, completing my boat, was fun.

The kit

The kit, first developed and manufactured by Graupner in Europe, comes
with a number of notable challenges. The hull and deck are fabricated from a fairly “soft” and flexible ABS material. The two components are brittle to impact and subject to distortions from inappropriate glues. More on that later. The challenge of effectively bringing together the hull and deck is formidable, and, is not appropriately addressed in the kit instructions. At the Micro Magic National Competition in Phoenix last Fall, I observed that deck / hull union was apparently a source of frustration for more than one competitor. The kit itself comes with very limited step by step construction dialog. Full size schematics, however, are good and complete. A word of caution regarding the alignment dimples on the deck and hull, … ignore them. My rudder was 12+ degrees off vertical, and required my cutting an unscheduled hole in the aft deck. The keel deck hole was too small and was 1/8 in. off center line. The stern deck / hull alignment was off 3/16 inch. Other smaller kit “discoveries” included: the main and jib booms being a little short for effective sail outhauls, and, the hatch closure being poorly designed, misaligned, and not user
friendly. The most important issue not addressed in the kit instructions deals with effective placement of batteries. Being the heaviest single item in the boat, battery location deserved a more thorough discussion.
A critical eye and common sense caught a majority of the kit’s shortcomings. On the positive side, the kit provides an array of opportunities for creative and rewarding problem solving, ….I found it the fun part of building a Micro Magic.

Construction Considerations

Get ready. I hate bowsies! In this discussion you will note that I favor the use of a proven alternative. For the purpose of securing cordage, I have opted for the use of 3/16 in. nylon machine screws. Where used, a slightly enlarged 3/16 hole is drilled into the appropriate location and a nylon nut is epoxied to the underside. Using a small screw driver, cordage is adjusted and secured under the head of the machine screw. After
five boats and no failures, I enjoy this simple arrangement!

  1. Selection of glue

Prior to starting construction, I took five pieces of scrap ABS
from the kit and tested the adhesive and thermoplastic qualities of three glues and four epoxies. Glues included Super Thin CA, Thin CA, Gap Filling Medium CA, and Shoe Goo. All appeared safe to use, but, Medium CA, with prep sanding, proved to have the best tensile adhesive quality. Shoe Goo didn’t make even a decent filler. Medium CA worked very well on both ABS and Carbon Fiber (CF). Two part epoxies included Devcon Plastic Welder, Ace Plastic repair, Loctite Extra Time Epoxy(60 Minute), and Loctite Marine Epoxy (two hour). With prep sanding, CA and Loctite epoxy worked very well on the deck / hull union. Medium CA was flowed between the deck flange and hull and Marine epoxy used for gap filling. All the above, especially the Loctite Marine epoxy, sanded and finished very well. A review of the literature reveled that some glues have proven to be too “Hot” for ABS. Caution should be taken.

2. Deck / hull union

When bonding the hull to the deck, the challenge is to effectively push the hull out and against the 5mm deck lip, ie: flange. The non rigid hull does not uniformly align against the deck flange. My solution was to create a 5 mm deep X 3mm wide trough on the bottom (inside) surface of the deck. This trough uniformly forced the hull wall against the overhanging deck flange. Using of lots of close pins, the fence was uniformly pre-positioned and glued 3mm inside the deck flange. Medium CA was used for bonding. (See Photograph) With the fence in place, the hull wall was prep sanded, placed in the trough, and secured with compression rubber bands and tape.(See Photograph). Medium CA was flowed into the trough to complete the union. With the edge of a finger and Marine Epoxy for filler, a uniform, strong, and esthetically smooth bead of epoxy was laid down between the hull and flange.

3. Jib boom weight Management

Rather than simply attaching the jib boom weight to the leading end of the jib boom, I elected to: (1) cut the head off a small 3/32 in. threaded brass bolt, (2) and insert the bolt into the forward end of a non kit 4mm DIA
CF boom, and (3) apply medium CA to secure the bolt in place. I then tapped the kit brass jib boom weight to match the bolt thread. This created a fore and aft adjustable jib boom weight. (See Photo.) The weight was secured in place by a like threaded nylon nut.

4. Forestay to the jib boom Attachment

 

The forestay, coming down from its pivot point on the upper mast, is attached to the jib boom using a small 1/8 in. dia. split ring. The ring was placed on the aft end of the threaded screw described above (#3). This
arrangement is very simple, very accessible, and very removable.

5. Boom to deck Attachment

My goal here may appear to be making the attachment as complicated as possible. But, not so. The attachment actually is a response to several
controversial goals.

Goal #1: Get the boom as close to the deck as possible;

Goal #2: Make the boom height off the deck adjustable;

Goal #3: Reduce tension, friction, and torque in the short cordage between the jib boom and its deck attachment.

Solution: (1) Make the cordage longer (from 1/4 in. to 1 1/4 in.), (2) secure the cordage to a point below the deck, (3) for adjustment, return the cordage to a point above deck. Using 3/16 in. dia. styrene tubing, continue the angle of the jib boom stay through the deck, around a 3 in. radius, and returned the loop to exit the deck 3 in. behind the entry point. In this water tight tube, the tension, friction, and torque of the stay is distributed over both a longer distance and a longer piece of cordage. After exiting the
hull, the stay (now a halliard) is taken to an adjustable machine screw located at the base of the mast (See opening preface). Note: The length of the jib boom halliard is now adjustable, and, the stress on the cordage is greatly reduced. This arrangement provides quick adjustment of both boom height off the deck, and, in conjunction with the back stay, the fore and aft tilt of the main spar (mast). Using a small screw driver, both adjustments can quickly be made when there is a change in wind speeds.

6. Back stay / transom Attachment

I opted for: (1) an 8 in. piece of cordage anchored on the transom, (2) extending this cordage up to a 1/8 “ split ring on the backstay, and (3) returning the cordage down to the transom. The return cordage is secured on the transom under the head of a nylon machine screw (see Preface). Sounds complicated, but, it makes for a very simple adjustable backstay. With the twist of a screw driver, you are ready for adjusting and securing. No bowsies.

7. Topping lift and forestay Adjustment

Note: The way I elected to configure these two items, would traditionally make them halliards; i.e.; Both pieces of cordage attach to a moveable item, follow a course up the mast, and then return to the deck. The common mast top return for both halliards is located approximately 27 in. up from the bottom of the mast. Returning to the deck, these halliards are secured under two very adjustable nylon machine screws (see Preface and Photo). To achieve a horizontal line to the screw heads, a 1/4 in. high X 3/4 in long deck fence is CA’d to the deck near the nut heads. The cordage (halliards) is passed through two 1/16 in. holes in the fence to the screw head. Again, a small screw driver affords the opportunity to adjust and secure these two halliards. No bowsies.

8. Battery weight Management

Note: This is a biggie! The battery in the MM is the heaviest single component in this two pound boat. In the five pound Victoria or the 10 pound Soling, the placement of the same weight is important, but, not as critical. The dilemma: How can you maximize the fore and aft tuning of the heaviest object in the boat? Ideally you would like to be able to move the battery to any location between the rudder post and the keel trunk. If this could be accomplished AND position the two servos in line with the
battery, you could achieve ideal beam to beam and fore and aft weight symmetry. The heaviest items in the boat would be as low as possible in the hull, aligned amidship, and be adjustable. A Solution: (1) Make a tunnel under which the battery can slide from the rudder post to the keel
trunk, (2) mount the servos in line on top of the battery tunnel. The lateral weight symmetry for both components would be ideal.
Fabrication: The tunnel is fabricated from three pieces of 1/16 in. Lexan. Lexan is a premium, poly-carbonate and can be purchased at Lowes in 12 in. squares. The tunnel has a 5 X 2 in. top and two lateral walls 4 X 1.5 in. The walls are angled out from the top at 30 degree angles. The three components are bonded with Med CA. Two identical Hittec HS-5085mg
servos are mounted end to end on the top of the tunnel. The battery, resting on the floor of the hull, fits comfortably under the servos. Lateral shifting of the battery is controlled by two 8 X 3/16 in. fore and aft, styrene “fences”. These battery guides are CA’d parallel and 3.75 in. apart
inside the hull wall. The width of the “trough” is dependent upon the width of the battery plus about 1/4 in. on each side. In this trough, the battery pack should move freely from the rudder post to the keel trunk. The battery / servo tunnel may be secured to the hull floor by whatever
means you wish. I enjoyed the use of small conveniently located nylon machine screws. A nice feature of the tunnel concept is that it is totally removable from the boat, …servos, servo arms, and battery. Tuning battery fore and aft: Note: don’t get lost here, – this really is simple. First determine the direction and posture you would like your battery pack to rest, – while under the tunnel. The direction and path of the battery leads going to the receiver must be given consideration. Once the position of the battery in the trough is determined, CA a piece of string to the aft (rear) end of your battery pack. Then CA a piece of string to the forward end of
your battery pack. Next, fabricate “returns” for these strings from 12 in. squares of scrap ABS. Drill a 1/16 in. hole in each return. CA one return near the rudder post and the other to the side of the keel trunk. Thread the aft battery string through the rudder post return and the forward
string through the keel trunk return. With the battery tunnel secure in the hull and servos installed with arms attached and sheeted, bring the two battery tail strings up and over the tunnel and tie them together. You now have a loop that: pull one string and the battery will glide back, pull on the other and the battery pack will glide forward. With a nylon machine screw
anchored on the top of the tunnel, you can secure or release the ends of the loop and position your battery in an infinite number of fore or aft positions. The servos remain anchored and in line on top the tunnel. The servo arms move free and un encumbered.

9. Aligning the rudder post

Caution: Do not use the dimples on the deck to align your rudder.
The goal here is simple: Make the rudder and keel perpendicular to the deck. Accomplishing this is not challenging. Start by moderately oversizing the rudder post hole located on the
cockpit floor. With the brass rudder post through the hole in the hull and extending up and
through the oversized hole on the cockpit floor, slide the rudder into place. Put a block under
the rudder to prevent it from falling out. This support will be used to tune the alignment of the
rudder fore and aft, and, beam to beam.
Next, place two identical small square pieces of wood on the deck edge (the gunnels) on each
side of the servo access port (hole). Bridge, beam to beam, the two pieces of wood with an 8
or 10 inch bubble level. With the boat hull in it’s cradle and rudder independently supported,
view the level from behind (astern) and level the deck. Next, drop an overhead plumb line and
bisect the boat transom. With the deck bubble level leveled, the line will be perpendicular to the
deck. The plumb line provides a visual reference for aligning the rudder and rudder post –
beam to beam. To align your rudder post vertically (relative to the cockpit floor), place your
level fore and aft on the cockpit floor and raise or lower the hull bow to achieve bubble level.
The rudder and rudder post are now vertical, – beam to beam and fore and aft. Using the
cockpit floor, It is now time to slip the snug fitting ABS collar over the brass rudder post tube,
and, with CA, “lock in” your alignments. When dry, remove the rudder from the rudder post.
With a mirror and a piece of wire, apply marine epoxy around the two in-hull rudder post exits.
Reinforcing these two stress points will protect the hull from the brittle nature of ABS.
With the rudder post now solidly secure, use a fine metal file or drummer grinding disc, carefully
hone the lower brass tube rudder housing flush to the hull. Leaving 1/16 in. extending from the
cockpit floor, perform the same procedure on the upper end of the brass tube rudder housing. It
is now time to trim the upper margin of the rudder. This margin should duplicate the contour of
the hull. Installed, the movement of the rudder from side to side should clear the hull by the
thickness of a piece of paper. The cockpit rudder servo arm should move smoothly from side to
side and be parallel to the cockpit floor.

Closing Observations / suggestions

  1. As noted, the ABS hull of the MM is brittle and vulnerable in impact situations. My hull came in a new box with a 8 mm crack on the bow, – at about the water line. A packet of accessories was in the immediate area. I resolved the problem with a 1in. X 2 1/2 in. piece of single ply, medium fine, fiberglass. The patch was laid vertically inside the bow and bonded with slow setting, two part, marine epoxy from Ace Hardware. A very small external cosmetic application of the epoxy resolved the problem. Surfaces were prepped by a light sanding. This relatively simple procedure was also performed at the junction of the keel box and the hull. To avoid future impact problems, I suggest following this procedure when constructing any Micro Magic.

  2. As noted, I personally enjoy using small nylon slotted machine screws and epoxied nylon nuts to secure, (1) the main and jib sheet length adjustments in the cockpit, (2) the back stay adjustment on the transom, (3) the jib toping lift and forestay halyard adjustments, and, (4) the jib boom deck adjustment.

  3. When binding the deck to the hull, there is a transition issue where the 90 degree deck flange stops and the slope of the aft deck to the transom starts. If nothing is done to reinforce this deck / hull transition, you end up with an unreinforced 90 degree hull to the deck glue job. Not good !! I opted to continue my styrene “fence” (see Deck / Hull Union above)
    through this transition, and around the inside margin of the transom. Taping the deck and hull together and then flowing medium CA between the fence and hull provides a much more stable union. Cosmetic filling was accomplished with slow setting, two part, marine epoxy and fine
    sanding.

  4. My main spar (mast) is unstayed. If, however, you wish to incorporate standing stays, I suggest not using the items provided in the kit. Glue failures are common. I and others suggest the following: 1. Make a 1/2 inch round disc from scrap kit ABS, 2. Drill a 1/16 in. hole in the
    disc, 3. Stick the head of a small cotter pin through the hole in the disc and flair the legs of the pin out and flat, 4. Epoxy the flared legs to the bottom side of the disc, 5. Drill a 1/16 in. hole through the appropriate location on the deck, 6. From the bottom side of the deck, stick the
    head of the cotter pin through the deck, then, 7. With the head of the cotter pin protruding through the deck, CA the top of the disc to the bottom side of the deck. On the deck top, use marine epoxy to cosmetically finish the area around the protruding cotter pin head. If this arrangement fails, you have demolished the deck of your boat and the boat will soon be resting at the bottom of the pond.

  5. Reducing drag. Drag and friction are speed killers.. Sailboats are unique, – they interact with two media, air and water. Separately or jointly, both have the potential of producing significant friction or drag. Air we manage and control with sails, hulls we manage by fairing the trailing edges of the rudder and keel. The trailing edge of each of these components should be
    sharp, able to cut paper, ….or at least cheese. Another form of drag is surface tension and / or turbulence. Researchers have demonstrated
    that very finely sanded (400 grit or more) and unpainted surfaces have less friction than shiny painted surfaces. Most of RC boaters do not paint below the waterline. They keep their keels, rudders, and hulls micro sanded and very clean.

  6. Painting suggestions: As noted above, painting below the water line is not recommended. Micro sanding and painting above the water line, however, is both fun and provides visual identification of your boat. Prep sanding with 300 – 400 grit paper and using Krylon Fusion (for plastic) has been successful for most in our sail club. Care should be taken
    to maintain the recommended 12 -14 inch distance from the hull, and allow an average of 1 hour drying time between thin applications. Thoroughly mix the contents of the spray can. If your finish “corn flakes” on you, let it dry, sand it smooth, and, start again.

  7. Mast Options: I elected to use an unstayed, 6.0 mm OD / 4.8 mm ID, 28 in. long, carbon fiber mast. I fabricated an aluminum mast crane. To prevent the CF from vertically splitting, I found it necessary to tightly wrap the mast head with fine cordage and glaze it over
    with epoxy. The forestay and toping lift halliard return is located 26.75 in. from the bottom of the mast. With two holes in it, the small piece of 1/4 in. thick Lexan is contoured to the mast and secured with medium CA. The bottom of the mast is plugged and glazed with epoxy.

  8. Boom options: I elected to use 4.0 mm DIA hollow CF tubing. A small cotter pin inserted and CA’d in the back of both booms provides a good outhaul attachment.

  9. Sail options: A review of the literature strongly suggests purchasing custom sails.

  10. Wet Tuning. When completed, Micro Magics’ small size makes it ideal for putting it in water and noting it’s resting “posture”. Using a plum line and viewing the mast from behind, you can accurately determine if the completed model sits flat on the water. A mast that is not vertical will respond differently on port and starboard tacks. Viewed from the side, the plum will tell you the amount of fore and aft rake present in the mast. As noted earlier, correlating mast rake with battery location in a two pound boat is critical.

Closing

I hope this information provides some insight into the fun you can have creatively solving problems. On the pond, this jewel of a boat will let you celebrate both your imagination and your ingenuity. It has for me. bb

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Building a MM – Micro Magic V2 Almost-Ready-to-Sail Assembly Guidance

Introduction 1 (merge with Intro 2)

This post explains the building of a Micro Magic almost-ready-to-race model yacht.

The contents of this introduction will be merged with Introduction 2 when this post is completed.

Assembling a Graupner V2 almost-ready-to-race (ARTR) Micro Magic model yacht is a reasonably straight forward project for those who have built model yachts in the past. “Non-modelers” may be a challenged – but it is certainly doable. PMYC members have access to other members who have building experience.

 The Graupner MM Manual makes the point “This item is not a toy. …. Assembly…. must be performed by experienced modelers….”  I think Graupner is overstating the matter. That said, the detail in the Manual is sparse — I think that’s an understatement.
This post has two perspectives. One is what I have named “Casual Sailing”.  The other is “Racing”. The Casual Sailing topics are, essentially, a reflection of the Graupner instructions. The goal is to get a boat in the water and sailing. The Racing topics modify the Casual Sailing procedures to reflect modifications that will make the boat easier to sail and go faster in a race. The post is not consistent throughout on this dividing because the idea evolved while assembly was underway.
My immediate focus is to complete the assembly and the Casual Sailing instructions. Upon completion of the Casual Sailing instructions I will return to the Racing info.
The Racing sections will be focused on the changes to the Casual Sailing instructions. Those changes will have to be modified by the input one receives by studying the several articles covering the building of a Micro Magic from a kit and the creation of a fast racing Micro Magic.
This post has become larger than I anticipated at the beginning. I am noticing that it is loading a bit slowly. I am going to divide it into multiple posts with an appropriate indexing at the beginning of the first piece.

The boat assembly and the Post content development are ongoing.

Please read these next few paragraphs (July 2017)

I am documenting the assembly of the boat as I do the assembly. So, if you are thinking about or already committed to the assembly of an MM ARTR, come back regularly. I don’t spend all of my time on this assembly or writing. So, the assembly project that I estimate will take most people 10 – 15 hours may extend over  weeks for me.

You may find this tedious reading. However, I assure you, that if you have to figure all of this out as I have done you will feel like you are building the kit from scratch — another challenging project. Be patient and work through the steps. The labor savings and resulting build quality will be worth it.

Call me (520-461-6473) if you want to discuss the topic. Or, email me.

Jerry

Introduction 2 (merge with Intro 1)

This will be the beginning of the Post when the boat is completed

Mid-June, 2017, the Pima Micro Yacht Club purchased two Graupner SA  MM ARTR (Almost-Ready-to-Race) boats. These boats are constructed by the manufacturer needing only final assembly. The idea for PMYC to buy a kit  was a hedge against a repeat shortage of MM’s experienced this year and to make it possible for persons new to the Club to easily obtain a boat that they could be sailing  relatively quickly.

The Graupner SA instructions are minimal. So, I decided to assemble the PMYC-purchased boat. And, will sell it when the boat and documentation is done. The focus of the build is  lot of research is going into this build. My sources are the multiple writings of MM gurus. The more significant of those writings are listed in the References Section below. I strongly recommending looking at all of them. My writings have drawn heavily on the content of these documents plus my experience as a model yacht builder going back to 2010.

The Manual notably lacks details and what information is there can be difficult to interpret unless you can examine a finished boat. This Post supplements the Manual, providing the desperately needed detail. It contains two perspectives on the assembly. One, to build the boat by the instruction (vague as they are). I label these sections “Casual Sailing”. This is a boat that can be assembled rather quickly and will make for a fine casual sailing experience. The second perspective is racing. I label these sections “Racing”.  This is the same boat but with multiple extra and sometimes time consuming steps, but will result in a boat that will be capable of being competitive – within the range of your boat handling skills and racing expertise. If you only interest is the casual sailing then use the label info. only.

As I said above, the focus of this post is primarily to help non-modelers. I have tried to give the guidance in a way that requires the least amount of purchases of tools and materials. If you are a modeler and/or have many, many tools, use the guidance to help yourself pick out the right tool or a better material based upon your experience.

Beyond the contents of this Post you can ask PMYC members for advice. And, be sure to look carefully at other boats for fitting-out ideas. A particularly good source is Jerry Robertson, Bill Brown and myself.

The emails for these PMYC members are:

A link to this Post is on the menu at the top of each page on the website (Assemble a MM V2 ARTR) so you can easily find it. It will be updated as I go along with pictures and narrative. As I am writing and assembling, I am thinking about assembling a package of “stuff” (I don’t really know what that might fully mean at the moment) that could be purchased along with the boat to make the assembly easier — removing most of the need to make yet another run to the hardware store.

References

Remember to read the Summer 2017, #188, issue of Model Yachting magazine. Several articles appear there that are of particular help in the assembly project. This issue of Model Yachting is a must have if you are to be a Micro Magic racer. Or, you can read the articles on our website.

In the writing, references to Mike Eades or Greg Norris are references to these two documents. Otherwise, I will identify any alternative source associated with these two gentlemen.

If you do not receive Model Yachting magazine, please support model yachting in America by joining the American Model Yachting Association. It costs $35 annually ($5 fee for the first year). The magazine is worth the price.

Here are two more highly relevant links for Micro Magic sailing:

A Caveat

I am not a professional writer. I am a fast typist. In my case that can lead to spelling errors, (finger movement errors). I proof read my writings regularly and my wife does some proof reading. But, after that I know that some grammar errors escape detection. I hope you will be tolerant. The key question I regularly ask myself is “Does it communicate?”. If the answer is “Yes”, then I have done my job reasonably well. If you would like to comment or add to the narrative, please Leave a Reply at the end of the Post. When I finish the project, I plan to spend more time on editing the material and adding more images.

Materials Needed In Addition to the Box Contents

The following is a list of items, in addition to those in the box, that you will need to do the assembly — prices are approximate where given. For my own convenience, I looked up item prices on the Internet. So, the numbers I give may be a bit low compared to local stores. For what I want to accomplish here they are good enough.

  • Stand Assembly
    • two wood blocks (2″ x 6″) to stabilize the stand-ends during assembly – get them at your local hardware or lumber store for free from their castoffs. – $0
    • Thin CA (3 sec. set) – $6.
    • Thick CA (30 sec. set) – $5. (Note: when using thick CA, you can instantly make it set by sprinkling Baking Soda on it. It makes the surface rough but does the job.)
    • Wood screws size: xx phillips head (for securing the stand ends to the wood blocks during assembly)

      Carpenters Framing Square – 8″ x 12″
    • Varnish or paint to protect wood – optional (krylon Clear Interior/Exterior spray – $5.)
    • A simple carpenters framing square 8″ x 12″ (See pic on right) – $5 – borrow it if you don’t have one
    • Drill to drill holes in the ends so that they can be stabilized during assembly.
    • Phillips screwdriver – borrow it if you don’t have one
  • Hull
    • Sheets – Tufline XP 15# – replaces the lines that come with the kit.
    • A small amount of 1 mm plastic sheeting to build a mounting platform for hte screw eye for the jib sheet. See the xxx figure.
  • Rudder
    • Allen keys (hex wrenches) – 1.5mm and 2.5mm. If you do not have a set of these keys, you can buy them at Ace for about $1.00 each.
  • Sails
    • Sail Tape or Sail Patch Tape – approx. $23 for 3″ x 15′, enough to strengthen the luff of the MM sails for 60 boats (3″ x 3″ piece). This could be part of a “PMYC MM Building Package” NOTE: I have enough to support the build of a dozen boats.
    • Sail Numbering Tools. I have access to my wife’s quilters cutting mat and transparent grid tool. It made the number application process easier. If someone in your household does quilting your have an immediate leg up on the sail application process.  Check around your neighborhood for a quilter. For reference the two products shown are made by Creative Grid and Crafty World (look them up on the Internet). The grid is 6″ x 12″ and the mat is 24″ x 18″. The mat is a bit pricey for this one project. So, the same carpenters square identified above would work as well. Use the grid that is in the sail material to help align the numbers.
Crafty World Quilters Cutting Mat
Crafty World Quilters Cutting Mat
Creative Grid

 

 

 

 

 

What’s in the Box?

Pieces & Parts

The Manual – four languages
The Box
Outstanding Paint Job. Notice the glare on the hull.
Rudder and Keel Spacers
Keel and Keel Bulb. The Keel has to be shortened a bit for racing. I’ll come back on this when I install the keel.
This is what you will see when you remove the box cover.
Rudder push rod and rudder post installed
Mast positioner and Jib sheet exit .
Sail sheets – ready to go

 

Micro Magic ARTR interior - everything is installed
Servos, sail servo arm, rudder push rod and power switch – already mounted. Interior is very neat and clean.
Servos, sail servo arm, rudder push rod and power switch – already mounted

Hull and More are Already Assembled

The hull, mast and keel com  completely assembled.  This is a step that allows you to skip about 10 hours of build time compared to building the kit. The completed items include:

  • The sail and rudder servo platforms are in place and the sail and rudder servos are installed and the arm connecting the rudder servo to the rudder in the cock pit is installed.
  • Keel box is in place
  • All deck fittings are installed
  • Deck is glued to hull
  • Rudder tube extending from the bottom of the hull to the top of the deck are installed
  • The keel is assembled
  • The sail sheets are installed. Note: the sheets are replaced for racing — and that I did change them in accordance with the Racing section below.
  • The mast and boom are assembled, including stays and jib topping lift
  • The sail and rudder servo arms are installed
  • the boot for the rudder push rod is in place
  • The rudder servo to rudder push rod is installed
  • Hull and deck are painted – and the job was well done
  • The sheets are in place. The jib sheet routing in the boat was changed. See Jib Sheets section below.

Note: you must provide the receiver and battery. This will be covered further along in this post.

First Impressions

My first impression upon opening the box is that Graupner does an outstanding job of providing a ready-to-sail product. Everything in the box was secured and neatly arranged. There were multiple packets of parts. The most impressive part of the package was the hull. It has a gleaming white painted finish that was obviously done by someone with a paint gun and skilled; not a spray can. The finish is smooth and dust-free. It was not until a few days after I opened the box that I removed the canopy. I was surprised at the neatness of the interior installation which included the servos and the power switch. If one does not particularly care to build a boat this is a great solution.

If you want to see the boat I have let me know. Unless you are strongly motivated to build, this is an excellent way to get into MM sailing.

Jerry Robertson and I agree that this boat is more fun to sail than the Victoria.

How Long Does it Take to Complete the Job?

I will do my best to keep track of the time to get this project done – not including the writing.

  • Build stand – 1 1/2 hours including applying a coat of varnish/paint followed by a light sanding to smooth the post-paint rough grain.
  • Install rudder – 1/2 hr.
  • Install keel – 1 hr.

MM Class Measurements

The items in the list reference the Class rules paragraph number. Link to MM class rules:

Micro Magic Measurements

Item Rule This Boat
2.1 – Minimum weight of sail ready boat 860 gm
3.2 – Axis of rudder from inner back-side of keelbox =210 mm  205 mm
3.4 – Bottom of lead ballast to the hull <=135 mm 137+ mm
3.9 – Leading edge of keel to front tip of bulb => 25 mm  38 mm
3.10 – Weight of the keel assembly including spacers 380-420 gm  415 gm
4.10 – distance from the deck to top of mast <=780 mm
 4.12 – Middle of mast-positioning slot to the jib boom deck connection  =176 mm  176 mm
 Mast diameter  5-7 mm  5/6 mm*
 Boom diameter  >=4 mm  4 mm
 * Top and bottom of mast are 5mm, center is 6mm.

Note: The MM V2 ARTR boat may not adhere exactly to the Class Rules.  See Blue items in table above. The following paragraph is from the Micro Magic Class Rules: (Jerry: that’s the boat in this article)

From: Micro Magic Class Rule – 2017

IMPORTANT!
Recommendation concerning the Ready To Race (RTR) boats.
These boats, entirely built by Graupner, like the Graupner 2014.HOTT or RFH (Ready For Hott Version), may not be 100% class-conform. Their keel may be a little too long and slightly overweight. Also the position of the jib and rudder may be different a little bit.
Nevertheless the organizers of a Micro Magic Regatta are advised to accept these boats to participate for the time being. This is very important for the growth of the class. Exclusion of these boats could mean that new MM-sailors with such a boat are not allowed to race, and this is undesirable.
July 2017 – Since this addition to the rules was made the manufacturing has been moved to China. The Chinese boats will be available in the USA in mid-August (Graupner estimate in June 2017).

Assembly

Step 1 – Assemble the Stand (MM 7)

Assembling the stand was one of the more frustrating task I

Stand showing the wood blocks and carpenters square in place
Stand showing the wood blocks and carpenters square in place

have executed in a long time. It was not until I had moved well along with the assembly when I realized that the cross planks connecting the ends are all

slightly warped. I’m sure that there is an easy solution but I don’t know what it is. Maybe Jim Haines can improve this section when he builds his boat. So, the challenge is to either find a way to strap it all together before you glue or fight the twisting or make new pieces. Not knowing another way I chose to fight.

I used small wood screws to attach the stand-ends to the wood blocks to temporarily stabilize them while I worked. Then one at a time I added the cross pieces fastening them with Thin CA. After I completed the assembly I removed the screws then went back to the joints with the Thick CA. With four slightly twisted cross pieces, the resulting assembly was inevitably also twisted. The good news is that the boat on the stand puts all four corners down on the table. so, in the end, it’s not a big deal.

Finally I put a coat of clear finish on the stand to protect it from moisture. That process caused the wood grain to rise. But, a light sanding with fine sandpaper made smooth surfaces.

After assembly, put the black thin strips with the sticky back on the tops of the end pieces to serve as a smooth surface for the hull to rest on. I found that one piece served both ends. So, I have a replacement piece. The challenge will be keeping track of it over time.

Here is a Comment submitted about the stand on July 1.

The wood stand issue that Jerry Walker points out here may be common to many MM boats either in either kit or ARTR form. I opened my own ARTR package only to find that two of the horizontal plywood braces for the stand were in bad shape. The braces are made of a thin (0.5mm) solid wood core with a single layer of nearly paper thin wood laminate on each side. The laminate on one side of each brace was delaminated nearly completely from the core. I attempted to re-glue the laminate to the core but it ended up a floppy, twisted mess. I would suggest buying a sheet of plywood at the hobby shop and making your own sturdy braces to replace the faulty Graupner parts. Don’t waste your time on re-gluing.

The wood stand issue that Jerry Walker points out here may be common to many MM boats either in either kit or ARTR form. I opened my own ARTR package only to find that two of the horizontal plywood braces for the stand were in bad shape. The braces are made of a thin (0.5mm) solid wood core with a single layer of nearly paper thin wood laminate on each side. The laminate on one side of each brace was delaminated nearly completely from the core. I attempted to re-glue the laminate to the core but it ended up a floppy, twisted mess. I would suggest buying a sheet of plywood at the hobby shop and making your own sturdy braces to replace the faulty Graupner parts. Don’t waste your time on re-gluing.

Step 2 – Hull

This step does not have an equivalent in the Manual. It is included here because, for racing, a change is appropriate.

Casual Sailing

Battery Strip

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Racing

Mike Eades recommends changing the main and jib sheet materials. Mike recommends a 50# test line. I recommend the 15# TufLine XP line. A spool contains 300 yards, enough to do more than a few boats. I have used this product on two Victoria models for three years without visible wear or breakage. A big benefit of this product is its high flexibility. The sail positioning will never be influenced by a stiffness in the sheets.

It is easier to make this change now as it will be tedious once the mast is on.

Make the new sheets the same length as the original and reuse the bowsies. (Jim Haines is experimenting with a smaller bowsie. This post will be updated to reflect his experience.)

For this project I changed the sheets.

Jib Sheet Routing

Note the orange rectangle in the center of the figure. The color is to draw attention to the area. A 1/8″ screw eye was embedded in a piece of plastic cut out of the unused keel spacers. I made a groove on one side of the piece, put the screw eye threads into it and cemented it to hte vertical piece shown in the figure. This screw eye serves as a turning point for the sheet coming off of the servo arm and makes its way to the cockpit and a bowsie adjustment. The line running from the screw eye through the photo date in the lower right corner is the sheet going to the cockpit.

hhfghfg fig. of drawing

Figure xx. Routing of jib sheet from bowsie adjustment in cockpit to the jib. See the nearby figure for detail about the screw eye turning point on the keel box.

Remember those extra keel spacers? we have a use for a piece of one of them.

Step 2a – Install the Rudder (MM 8)

Casual Sailing

General

The instructions, Page 8-20 are a little hard to follow. But, it is just three parts; the rudder, a spring and the arm. The push rod post has already been added to the rudder arm — see the right side of the page near the Allen key for this assembly. You will need a 1.5 mm and a 2.5 mm keys in the future to make adjustments to the boat. If you do not have the two Allen key sizes: 1.5 mm and 2.5 mm, you can get a set of metric keys at Ace, making sure that the two sizes ares included. You will need these two keys in the future to make adjustments to the boat. The 1.5 mm key also fits the post on the rudder servo arm in the boat.

The rudder shaft is steel and will rust. Simply use petroleum jelly to grease it. And, periodically, remove the rudder, clean the shaft with steel wool or kitchen cleanser and replace it, renewing the grease. I am not going to lube the shaft until the end, in case I have to remove the rudder during the rest of the boat assembly.

Connecting the Servo and Rudder Arm

The positioning of the rudder push rod oat the two ends needs a bit of explaining. (See Rudder/servo connection image . Notice that the connector on the servo end of the rod is in the last hole. The connection is on the inner hold on the rudder end.

Rudder/rudder servo connection. Use outer hole on servo end, inner hole on rudder. The hole will have to be enlarged a bit to accommodate the post. The rudder arm is not tightly attached. See the text about the solution.

If you do not use these two hole positions you will find that the rudder arc is narrow and that the boat does not turn easily. If you have a transmitter with a Travel Adjust setting, then also adjust the travel so that you get about a 45 degree travel on each side of neutral. If you do not know how to make setup changes on your radio contact a local hobby shop (In Tucson contact Hobby Town on E. Speedway.). As a last resort, read the transmitter manual.

See the next section for dealing with the hole in the rudder-end control arm.

Rudder arm post not secure on my boat

In the process of moving the connector post to the inner hole in the rudder control arm, I noted that the threaded lock nut fitting on the underside of the connector on the rudder arm was not tight – and could not be tightened without binding. Worse, the nut could not be threaded on far enough to engage the locking portion of nut. My solution was to drill out a small indent in the bottom of the arm – enough to allow the lock nut to engage the threaded post. Be very careful with the drilling. The bit tends to bind in the soft material of the arm and could go all the way thru – then time for a new arm.

Racing

a. Rudder Tube Protruding from bottom of Hull

I ground down the metal rudder tube protruding below the hull so that the rudder fit closer to the hull. You may have to shave the top edge of the rudder slightly to make it fit the hull shape.

Step 3 – RC Transmitter/Receiver

a. Transmitter

If you already have an RC transmitter, you are likely not interested in this section. If you do not then keep it simple by looking around for a used transmitter – Spektrum’s DX6i’s or later are easy to find and cost under $100. Or you can obtain a new HobbyKing Orange Transmitter for about $65.

You can view  this radio at the HobbyKing website.

HobbyKing DSM2 Orange Transmitter.

b. Receiver

Used rc receivers are more difficult to find. but, no worry. You can purchase a HobbyKing Orange R610V2 DSM2 6 channel receiver for under $10.

You can view this receiver on the HobbyKing site.

HobbyKing OrangeRx R610V2 Lite DSM2 Compatible 6CH 2.4GHz Receiver w/CPPM

c. Battery

AA Battery Pak(comes with the boat) – comes with the boat. Adding replaceable Duracell AA batteries yields a weight of 110 gm.

The simplest battery solution is to use the AA battery pak that comes in the MM box. You can use Duracell Alkaline AA batteries that can be found everywhere. Don’t forget to check out Costco’s for their own label or the Duracell’s. Their prices are usually lower than anywhere else. Simple (non-rechargeable) batteries will power the boat for at least a dozen outings of 2 or 3 hours each. The Duracell AA battery at Costco has the part number MN1500. My estimate is that this is a 1500 mah battery; plenty for the MM.

You can also use rechargeable NiMH AA batteries with the battery pak. Of course, you will need a charger. Talk to other sailors about this topic. It’s too much to cover here.

If you want to lower the weight you can use a

800 mah AA 5-Pak – powers the boat for, at least, several 3-hour outings. Weighs 64 gm.

rechargeable AAA NiMH battery pak of about 800 mah obtained on the Internet or from Batteries Plus. This will get you multiple several hour outings on the pond. The 5-cell pak, shown in the nearby figure, is charged weekly after 3 hours on the pond in about 10 minutes at a 1 amp charge rate.

You can get an even lower weight by using a LIPO. rechargeable pak. The weight of a 7 V Battery is about 57 gm.

Step 3a – Install the Boat Receiver and Test

Casual Sailing

The receiver

 

Racing

Set the Travel Adjust on your Transmitter for the Aileron Channel to give you a 90 degree rudder travel.

 

Step 4 – Install the Keel (MM 9)

The MM instructions, Page 9-20, do not identify the spacers needed for keel installation.   You will use the narrow spacers. Discard the wide ones.

The keel fits very tightly inside the keel trunk. The first step is to sand the keel box a bit with particular emphasis on the immediate opening at the hull. It appears that paint has gotten inside. Also sand the keel insert until the fit is snug but not tight. Never force it in, as this could blow the keel box apart, and that is a very difficult repair.

Use a 1/8″ drill bit to open the deck hole a little to allow passage of the screw. There was paint in it making it a bit too small for the screw on the top of the keel.

The keel will be centered in the slot. This means that only the narrower of the spacers will be used, one on each

Keel insert with standard narrow spacers and extra spacer new keel
Keel insert with standard narrow spacers and extra spacer new keel

end of the keel insert. See Fig xx. Retain the wide spacers for possible use elsewhere. Sand the spacers to remove the mold marks. Glue both in place with CA glue. Note the length difference.  This build concluded here with the keel able to rotate fore and aft. by about 3/16″ pivoting on the screw at the deck. No good. I added a 1″ long spacer on the aft side of the insert approximately 3 mm thick (fore and aft).  The keel fits snugly now. The screw prevents motion at the deck. Note the image showing the keel with the box spacers and the additional one immediately above the keel fin.

Insert the keel into the trunk until it won’t go further. Move it back and forth until the screw comes out of the hole. The screw will be sticking out of the deck by about a 1/4″.  Put the washer and nut on the screw sticking out of the deck and finger tighten it.

Notice that the forward edge of the keel is recessed in the hull by about 2 mm. That is expected with the MM.

The keel is installed. The topic of the angle of the keel bulb to the water line will be revisited at the end of this post. Meanwhile its time to move on.

Step 5 – Check the Alignment of the Keel and Rudder

Casual Sailing

Any misalignment of the rudder and keel is of no consequence.

Racing

At this point in our assembly, you can check the alignment by putting the boat on the stand and then sighting between the keel and the rudder. This boat’s keel and rudder are slightly out of alignment. Note: my own MM, #180 has the same condition — built from a kit. The is an item that needs to be investigated with the MM gurus. I put it on the Finalizing Items list at the end of the post.

Step 6 – Prep the Sails

Casual Sailing

The jib is ready to install on the boat. The main sail has holes in luff for the metal rings. Install the rings – with the exception of the top one (the top ring is above the jib mount fitting on the mast). For consistency place all of the rings in the same direction. With the rings installed you can insert the mast into the rings. Add the top ring. See the Racing section for another aspect of the ring placement.

Adding sail numbers and your home country are your choice. If you want the numbers, see the Racing notes below.

Racing

Main sail attachment points

 

Add numbers and country letters

Having numbers on your sails is mandatory for participation in racing. However, for Club racing (only our own members) though numbers are mandatory you are not required to register your boat. Usually, any unique number among those in the local fleet is acceptable. That said, I strongly recommend registering your boat with the Micro Magic Class. By doing so you are supporting the work of the Class.

So, register your boat and put the sail number on the sail. Putting your numbers on the sail before it is on the mast is much easier than after it is on the boat. Get your sail number by contacting the Micro Magic Class Secretary. Send your sail number request to mm@theamya.org.  The sail numbers are three digits. You can request a specific number though there is no guarantee of its availability. Ask for several numbers. Or, in my case, I asked for a number with sevens and ones. I got #717. This is a number that is easy to put on the sail. You can pay by check or PayPal (perhaps some credit cards).

Putting the numbers on the sail is tedious but not difficult. The greatest challenge is to end up with the numbers evenly spaced and more or less parallel to the water. See the Figure of my sails. I will give the dimensions I used for your convenience.

Number and country positioning on the sails
Number and country approximate positioning on the sails
Jib with numbers near foot of sail
Main Sail with numbers near middle of sail. USA letters not on yet.
Example – Sail and numbers template taped to cutting board. Use Sharpie to draw the numbers on the sails

Now for the number positioning on the sails. The size of the numbers and letters on the sails are specified in the “Locating The Numbers on the Sail” in the Reference Section near the top of this Post. The document referenced provides an exact size template for the required lettering, the MM logo and the numbers 0 – 9. The MM Class rules do not address the detailed placement of the sail numbers on the sail.

The MM Class Rules state:

The mainsail must display a class provided sail number and country designation…. Letters and numbers should be of a good contrasting color and completely filled in.

It is conventional to place the numbers on the starboard side of the sail above those on the port side.  The placement of hte numbers is identified in the “Locating The Numbers on the Sail” link in the Reference Section near the top of this Post.

Noting the comments in Greg’s article, I measured the above-deck part of the mast. It is about 28 5/8 “. With the boom and mast installed on the boat the distance between the top of the boom and the bottom of the mast head crane is 5/8”.

Step 7 – Mast & Main Sail

Remove the two pieces of tape from the mast. We’ll sort out the use of the strings later.

The total mast length is 31 7/8″.

Casual Sailing

a. Mast

Jib (short sting connects to the top of the jib), fore stay string (attaches to the deck at the frront of the boat.), topping lift (attaches to the aft end of the jib boom.

The three mast pieces have been connected (above the jib attachment point and the bottom 2″ of mast)  and the mast head crane and jib/topping lift attachment point have been installed. The long string from the end of the mast head crane is the back stay. The long strings attached to the jib attachment point (the strings extending to the left of the mast) are the topping lift (string connects to the aft end of the jib boom) and the jib fore stay (string connects to the deck at the bow). The short string attached to the jib attachment point is the jib halyard — attaches to the top (head) of the jib sail.

b. Sail

 

Step 8 – Installing the Mast and Main Boom

 

Do you want to be a competitive sailboat racer?

Everything that has proceeded this section has been focused on getting your ARTR boat in the water. The details of making the boat as fast as possible are not addressed. This section addresses those topics that improve rules compliance or boat performance. THESE ARE NOT NEEDED UNLESS YOU ARE A SERIOUS RACER. If you are serious about the racing, you will likely be better off building your boat from a kit.

  • As you have already read in the Class Measurements section, the MM ARTR is not totally compliant with the class rules. Compliance with Rule 3.4 is straight forward. Shave the top of the keel insert to get the measurement in compliance. Establishing compliance with Rule 3.3 i. will require removal of the rudder tube and resetting it. That is not difficult but will require some redo on the construction and will be a bit tedious.
  • There is another matter that is important to MM performance. That is the angle of the keel to the surface of the water. When this keel was installed after the spacers had been inserted, the bulb was pointed downward by a couple of degrees. Greg Norris’ “Building a Micro Magic” article appearing in the Summer 2017 issue (#188) of Model Yachting and on this website (http://pimamicroyachtclub.com/2017/04/27/building-micro-magic-gregg-norris-may-2017-model-yachting/)  addresses the topic of the preferred angle of the keel bulb relative to horizontal in the section titled “On to the keel fin and bulb and rudders”. In that section, it is desirable to have the front of the bulb angled upward between 0 and 3 degrees. Given that the keel on this current boat is already built we cannot exactly follow Greg’s instructions. My approach to assessing (and fixing) the bulb tilt are presented in the “Bulb Tilt” section at the end of this post.
  • Wet sand the hull using 400 and 600 grit wet or dry paper.

Keel Tilt

This section was referenced in the earlier “Install the Keel” section. The purpose of this section is to address the subject of the tilt of the keel bulb and to explain how the bulb tilt was estimated and what was done to correct it. (Its original tilt was front down. The desired is the front tilt up 0 – 3 degrees relative to the rear of the bulb.

I placed this section at the end because unless you want to participate in inter-club regattas this topic is not of great importance. For PMYC club racing any disadvantage it may represent could be offset by good sailing and racing skills against all but the fastest boats.

Before getting into the details I have included the words from an email I sent to Greg Norris along with his response.

June 30, 2017 Jerry wrote to Greg Norris:

In you’re Model Yachting article you state that the mark on the bow “…just above the round area at the bottom of the bow”. However, the picture appears to be showing the mark near the bottom of the round area. To me this is where the mark needs to be – at the water line at the bow. That is exactly where the water line on my boat is.

June 30, 2017 Greg responded:

So, in light to moderate air I place the battery so that the transom is just kissing the water at rest, and I now make my keels with the bulb cant at 2-3 degrees upwards, or 87-88 degrees as you likely measure it.

What is truly optimal in a MM is however unknown.  Optimal bulb cant in a towing tank with an IOM is 3 degrees, with 0-2 degrees being very similar, but anything over 3 degrees upward or any negative (downward) can’t being much worse.  I know of no testing in rc boats in waves or under actual sailing.

 

  1. Put keel in boat and gently tighten the nut.
  2. Put a pencil mark at the bottom of the round of the round area at the bottom of the bow.
  3. Put boat in stand on a smooth table.
  4. Position the boat on the stand until the distance between the mark on the hull and the table and the bottom of the center of the transom are equal.
  5. Measure the distance from the front and back tip of the keel bulb — the hypotenuse of a right triangle (130.5mm).
  6. Measure the distance from the front and rear tips of the bulb to the table.
  7. Subtract the two values. Hopefully, the front value will be larger than the rear. This is the Opposite side of a right triangle.
  8. Calculate the angles using a calculus calculator such as CSGNetwork.com. One angle will be approx. 88, the other 2. You want the larger angle to be between 87 and 90 degrees.

After all of this be sure to read Greg Norris’ Summer 2017, Model Yachting article. or, read it here: http://pimamicroyachtclub.com/2017/04/27/building-micro-magic-gregg-norris-may-2017-model-yachting/

Finalizing Items

  • Shorten the keel according to the manual on Page 9-20
  • lubricate the rudder shaft
  • Remove the text at the top of the doc.
  • Neaten up the images at the beginning of the doc
  • Snug up the keel nut.
  • Keel/rudder slightly out of alignment.

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Batteries for Your Micro Magic

Battery Variables

It was easy to choose batteries for our Victoria’s. The preference was five AA batteries (approx. 6 Volts in a rechargeable battery or 7.5 V. in a standard battery), though a significant number of our skippers elected to use four cells (approx. 4.8 V. in a rechargeable battery or 6 V. in a standard battery). The argument for five cells is faster servo movement and increased servo torque, both a boat performance benefit.

Whether you are using four or five cells there is another parameter to be kept in mind. That is the ampere hour rating. An ampere hour (abbreviated Ah, or sometimes amp hour) is the amount of energy charge in a battery that will allow one ampere of current to flow for one hour. So, a milliampere hour (mAh) is 1000th of an ampere hour. As a practical matter the mAh value determines how long a device will run before the battery needs recharging. In the Victoria, I typically used 1500 – 2000 mAh batteries. This guaranteed that I could sail the boat all day on one charge.

Battery pak for removable or rechargeable standard AA cells
Battery pak for removable or rechargeable standard AA cells

A quick divergence. Standard, non-rechargeable, batteries are 1.5 Volts each. Some of our skippers used 4 standard batteries in a container with complete satisfaction. As far as I know, one cannot purchase five cell containers.

Micro Magic Batteries

AAA battery pak for a Pima Micro Yacht Club Micro magic model yacht
Five 800 mAh AAA batteries purchased on the Intenet and assembled into a pak by Batteries Plus with a wire and connector provided by me. (Batteries Plus does not offer the wire – you must provide.)

The Micro Magic ready-to-sail weighs less than one-half the Victoria (860 gm or about 31 oz., less than 2 lb.). The most c

ommon battery selection is five rechargeable AAA’s of about 700 mAh. According to Mike Eades, this will provide several hours of racing time. His view is to use this low mAh battery and change it out during the lunch down time at a regatta. My 800 mAh pak weighs 66 gm., about 2.4 oz. After the pak was assembled and shrink wrapped by Batteries Plus, I sealed all openings with silicon seal to keep the water out.

 

The following is the configuration and weights of my battery paks for reference. Obviously, the most significant weight variable is the number of cells. But, also n

5 cell AA for a Pima Micro Yacht Club model
5 cell AA

otice that the weight is also associated with the mAh rating.

5 Cell, 800 mAh AAA = 66 gm (2.37oz) (this is the 5 800 mAh battery pak shown above)

4 Duracel, 1150 mAh AAA in a plastic battery container = 54 gm (1.93 oz)

4 cell, 2000 mAh AA for a Pima Micro Yacht Club model
4 cell, 2000 mAh AA

5 cell, mAh unknown AA = 133 gm. (4.75oz) (my guess on the apparently low weight is lesser mah rating)

4 cell, 2000 mAh AA = 120 gm (4.34oz) (I have two paks at this weight; both Batteries +; so no surprise)

Note that the 5 cell AA weighs 133 gm while the 5 cell 800 mAh AAA weighs 66 gm, a 2.4 oz difference.

Batteries for Battery Paks

My new battery pak for my Micro Magic is composed of five tabbed batteries I found on the Internet. Tabbed batteries make it easier to assemble paks. I started my search for cells wanting Panasonic Eneloop’s. I could not find them. Next I investigated tabbed batteries from any source. The image to the right shows the typical battery appearance that I found. Though t

QRW Tabbed Cells for Pima Micro Yacht Club model yachts
QRW Tabbed Cells

he mAh rating was given, there was no information upon which to make a quality judgement. Somehow, I

made the decision to purchase them from QRW Solutions on Amazon (Duh! Where else?). Like I said previously, quality unknown. I purchased six cells; the company sent me seven (i hope that isn’t an expression of their expected quality). My total cost was $10.

Battery Tabs

I have constructed a battery pak using short pieces of wire

Nichol Tabs used to make battery paks
Representative Nichol Tabs used to make battery paks

as “tabs”. One soldiers the wires to the batteries, preferably using a soldiering gun as it can product high heat very quickly. High heat applied for a second to properly prepared batteries does the job without damaging the cells. Using wire connections is not desireable. It took too long to deal with each soldier joint as the wire wanted to fall off of the battery. There are three choices to this subject if you want to prepare a pak. Buy tabbed batteries, buy the flat pieces of metal shown in the red-background image, or buy tabs with holes as shown in the other image.

Nichol tabs with holes in each end - preferable to the flat pieces of metal
Nichol tabs with holes in each end – preferable to the flat pieces of metal

Based upon my experience, the first choice is the easy way to go, whether you assemble the pak yourself or have Batteries Plus do it. The second choice is the tabs with the holes. Based upon videos I have watched on the do it yourself approach, they look like the easiest to me.

 

I asked the folks at Batteries Plus about their opinion about the best AA, AAA batteries. It was Sanyo and Samsung at the top. This needs to be investigated, because when I did a “best aaa battery” i did not see these companies.

Note: all weights were taken on my kitchen scale. I know it is not exactly correct, but for our purposes here it is sufficient.

Review Graupner/SJ Racing Micro Magic Best. Nr. 2014.V2

This Post uses one of the links in the Building a Micro Magic – Greg Norris – May 2017 Model Yachting post. In the Building article it is identfied as an article comparing the v1 and v2 MM. The link appears in the Introduction section of the post.

It is included here to provide an easier to find the article.

The link is:

[http://micromagic.info/wp-content/uploads/2016/02/Review-Kit-rMM-2014-V2-English.pdf]

You can print the article from the Greg Norris post. See above.

 

Our Documentation on Building a MM is Improving

For the complete set of MM building documentation that exists, as far as I know, about building a Micro Magic, click on the Model Yachting Magazine Category.

If you want to print an article, you will have to click on its title; taking you to a place where only the one article will appear. At that new location you will see the Print icon appear under the Post title.

To return to the list of articles click the Back arrow or button on your screen.

Building a Micro Magic – Greg Norris – May 2017 Model Yachting

Building a Sturdy, Light, and Fast Micro Magic

by Greg Norris in close collaboration with Ralf Bohnenberger and Jack Chambers

 Meet the authors

Ralf Bohnenberger is one of the leading German Micro Magic skippers and he’s very active on the in MM International website.  He’s a

IMG_8283.png Caption: “Ralf Bohnenberger” Photo credit: Pat Bohnenberger

n engineer and an excellent modeler.  His boats are very well built and full of good of ideas. He would not dream of sacrificing complexity for simplicity.

Jack Chambers is one of the Azura MYC MM skippers.  He is actually very new to sailboat racing.  However, he used to make wind tunnel models for a living and he now builds gorgeous RC-gliders from scratch.   His mode is over the top perfection.  His favorite noun is Reynold’s number and he studies aerodynamics as a hobby.

Greg Norris (no picture) is an ok MM racer, also out

DSC0658 Jack Chambers - Photo Credit: Greg Norris
Jack Chambers – Photo Credit: Greg Norris (DSC0658)

of the Azura MYC, who is also the US class secretary.  He is an adequate modeler.  He is into light, sturdy, fast and bright colored.  He doesn’t spend much time with pretty or very cool, even less with complexity or perfection.

 

Note:  All photographs are by Ralf Bohnenberger and Greg Norris.

Introduction

In this article, we will show you how to build a sturdy, light-weight, fast Micro Magic, whether you have one of the old German racing MM kits or one of the new Asian Graupner SJ kits. For the rest of this article, we will refer to the old kit as v1 and the new one as v2.  If you happen to have a v2 Carbon Edition kit, we will discuss that as well.

If you are going to build a Micro Magic, you will rather quickly note that the directions that come with the kit are not exactly what you had in mind, no matter what it was that you actually had in mind.  Happily, the instructions seem to be slowly improving and there’s lots of other help:

You’ll want print out and read Peter B’s parts list and build instructions.  These are old, but the pictures, order, and overall instructions are excellent.  They are tailored to v1s, but most of it is at least very similar with v2s.  [http://usa.magicmicro.org/p/forum/forum_viewtopic.php?2452]

Then you’ll want to look at two articles on the MM International site:

Ralf has a piece where he very carefully compares the then new (2014) v2 to the v1. Interestingly, this article morphs into an early v2 build article.  [http://micromagic.info/wp-content/uploads/2016/02/Review-Kit-rMM-2014-V2-English.pdf]

Separately, there is a nice short piece on how to make a v2 boat class legal.  Read this if you are interested, but both of our boats will be class legal and we will discuss and make all of the (minor) adjustments necessary to do this.

Lastly, we will build two fast, sturdy, simple boats, but we’ll have plenty of pictures of Ralf’s beautiful work if you are inclined to the really cool, as well as pictures of Jack’s artwork if you are artistic and like really slippery stuff.

Instead of giving supplier information throughout the article, there is a supplier list at the end of the article.

v1 and v2

One thing that we will not be discussing are the pros and cons of the various differences between v1s and v2s.  You can read about that in Ralf’s link above, though I would stress that v2 MMs are steadily improving, and the kits that we are building now are a good bit nicer than the very early one he reviewed in his piece.  The most important thing to know about the relative performance of v1s and v2s is that at the 2016 MM European Championship v2s won and came in 3rd, while a v1 came in second.

Right out of the box both kits look great.  The v2 is of slightly thicker ABS than the v1, but more importantly, in places where the material is pulled thin by the mold (bow, bottom of the hull) the v2 feels noticeably sturdier.  The weight of the hull, deck, keelbox, and hatch is 208 grams on the v2, 185 on the v1.

The bulkheads and strengtheners on the v2 are mostly ABS, plywood on the v1.  And they used to come glued in place, but more recent versions have some plywood pieces and aren’t pre-glued.  Just play that by ear.  I’m really happy that the v2 kit seems to be under slow, steady continuous quality improvement!  You’ll also note that we don’t use many of the strengtheners on either the v1 or v2.  Actually, if Ralf had his way, we’d have used almost none of them.

Rudder Post

The first step on the v2 is to drill the hull rudder post hole.  It goes 210 mm from the aft edge of the keelbox, measured on the bottom side of the hull and centered with calipers.  Remember that the ABS grabs drill bits badly, so start with a small bit and work up to the final size.  Ralf says that you only need the rudder post reinforcements if you are an amateur.  Well then call me an amateur.  I used the bottom one, but agree that the top one is not important.  There is no reason to drill the deck rudder post hole now.  It’s easier later. Now glue the rudder post reinforcement in place.  When dry, drill out the hole until the rudder post can be inserted easily.  Then put the rudder post aside.

Glues

And it’s a great time to talk about glues:  ABS to ABS you should use an acetone based glue.  I screwed up and missed an early tip from Ralf to use Uhu Plast Special (hereafter “Plast”).  Instead, I used Testor’s model cement and it was very much less “hot” than the European stuff that I’d used previously. For wood or brass to ABS, as well as for ABS to ABS when I couldn’t clamp well, I used a German epoxy not available for purchase in the US – Pattex Stabilit or Uhu Acrylit (hereafter “Stabilit”). It’s clamp time is about 10 minutes, which means that you can hold pieces in place while they are drying when clamping is hard.  And the bonding of whatever to ABS is fabulous.  Highly recommended.  Just a reminder:  be sure to rough up any surfaces being glued with 100 grit sandpaper, then clean them with naphtha (lighter fluid) prior to gluing.

V2 Carbon Edition Kit

And it’s also a great time to discuss the v2 Carbon Edition kit.  These boats look really trick.  They are transparent ABS with carbon fiber looking paint on the inside.  Assembly is identical to the usual kits, except that you need to sand off the CF paint at all glue junctions.  You’ll be thinking that this will screw up the look, but really it’s just a great opportunity for some really cool racing stripes.

 

Keel Box

Glue the keelbox together with Plast and clamp till dry as in the photo. Glue the mast ram reinforcements to the keelbox with Plast on

Glue the keelbox together with Plast and clamp till dry as in the photo. Glue the mast ram reinforcements to the keelbox with Plast on the v2, Stabilit on the v1. (DSCN0083)
Glue the keelbox together with Plast and clamp till dry as in the photo. Glue the mast ram reinforcements to the keelbox with Plast on the v2, Stabilit on the v1. (DSCN0083)

the v2, Stabilit on the v1.

DSCN0111.jpeg Caption: “Glue in the keelbox with stabilit. Just hold it down and in place till the glue hardens. Be sure to get the stabilit under the little lip on the hull and cover lightly over the edges from above as shown.”

Glue in the keel box with stabilit.  Just hold it down and in place till the glue hardens.  Be sure to get the stabilit under the little lip on the hull and cover lightly over the edges from above as shown.

Sail Servo Holder

If you’re building a v1, use the plywood sail servo holder provided, but cut away the plywood on the right intended to hold on a jib servo (which is not class legal).  On the v2 you’ve likely got some choices.  In my kit, I received a plywood servo holder and two plastic ones.  All three were too flexible.  I could have glued two of them together, but instead I just cut out a copy of the plywood one out of 1mm CF plate.  Looks trick and is very light and stiff. (Be sure to wear a mask and eye protection when working with carbon fiber!)

DSCN8268.jpeg Caption: “Or you can copy Jack’s work of art.”

Or you can copy Jack’s work of art (DSCN8268)

 

 

 

 

DSCN0102.jpeg Caption: “v2 style rudder servo plates. (see text

 

 

v2 style rudder servo plates (DSCN0102).

Rudder Servo Mount

The rudder servo mount on the v2 is really trick. If you’re building a v1, just make a copy of the v2 version out of 1 mm CF plate, a piece of thin plywood or some spare plastic (like an old credit card).  I liked the CF one I made for the v1 so much that I made another for the v2.  That was unnecessary though.  The stock plastic one is fine.  Since it was CF plate, I glued this on with Stabilit.

Bow Reinforcement

Concerning the bow reinforcement, you need to make a choice, but you can’t really make a mistake.  Take a look at the diagram below.  This is how Ralf fastens his jib boom to the deck.  It is ultra-cool and saves a gram or two.  Alternatively, you can just use a cotter pin glued to the deck as in photo x (No photo).  Both methods work fine.  But if you opt for the cotter pin, I think that it’s better to include the bow reinforcement, since

Ralf’s jib hook final.jpg Caption: “Ralf’s really trick jib boom deck hook.” Credit: Jim Linville

this gives a much greater area to glue the front of the deck to the hull so that the tension on the jib boom doesn’t separate the deck from the hull.  Since both of these boats will sail out of the Azura MYC and all Azura rigs use the cotter pin method, we opted for this.  But for most new builds I think that Ralf’s method is a better choice.

 

 

 

DSCN0100.jpg Caption: “Deck layout”

To the right are the deck layouts for the v1 and v2.

 

 

 

 

 

 

“Ralf’s internals. Note that he does not have a battery slider. He has a whole battery car that he can pull back and forth from the outside”

 

 

 

 

Jack’s internals. (DSC00456)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hatch and Power Switch

Now glue in the little blocks to hold the hatch fasteners in place.  Ralf doesn’t use them, he tapes his hatch in place.  But he also uses a cool magnetic power switch for the hull electronics.  I don’t bother a switch.  (A 700 mAh battery will easily get you through half of the longest full race day without any switch at all.  Just change batteries at lunch.)  You decide.

Reinforcements

I did use the transom braces.  Actually, after I destroyed the v2 transom brace while trying to lighten it, I made a new one out of 1mm CF plate.  I liked it so much that I made one for each boat.  This is however unnecessary.  The kit ones are fine.  We did not use either of the big main bulkheads on either boat (more about that further down).  You do not need the stern deck reinforcements.  Glue a ~1.5mm cotter pin in place for the backstay using Stabilit and similarly glue your bracing and hook or your bracing and cotter pin in place for the jib boom attachment.  The hook/cotter pin should be 176 mm from the center of hole for the mast.  On the v2 ignore the dimple on the deck.  It is in error.

If you’re planning to use the cotter pin method for the jib boom deck hook, the reinforcement for the little screw should be 65 mm in front of the center of the hole for the mast.  You do not need to use the entire deck reinforcement piece for either method.  You will not need side stays, so leave out the reinforcements, and indeed if there are any other reinforcements that we’ve failed to discuss, leave them out.  Finally, varnish any wooden reinforcements with a single coat of varnish.

DSCN0124.jpg Caption: “A little two-sided CF house to catch the aft end of the battery slider so that it doesn’t bounce around.”

You will have noted that I glued some sponges in place.  I think that it makes no sense to have water sloshing around the boat when sailing in heavy air.  Also, I built a little two-walled house to catch the aft end of the battery slider.  It is made of 2 pieces of 1mm CF plate and a roof of 0.3mm CF plate.

Glue the Deck

Now it’s time for the most exciting part of the build!  We are going to glue the deck onto the hull.  First, trial fit carefully.  This is simple:  you want the hole for the mast on the deck to snap into place in the keelbox.  On a v1, this means that you’ll need to trim away a little of the flange in the bow, since otherwise the deck will sit about 2 millimeters too far forward.  On the v2 the deck fits pretty well right from the start.

In Peter B’s build article, he uses a bunch of rubber bands as his clamps.  I like masking tape better.  Either way, be sure to practice mounting the deck to the hull about 5 times before actually using any glue.  Also, be sure to cut all of your masking tape strips prior to gluing.  I

DSCN0132.jpg Caption: “Gluing the hull”

used Stabilit at the keelbox/deck junction and if you used the cotter pin method for the jib boom attachment, use it at the bow reinforcement/ deck junction as well.  Use Stabilit in the transom area for sure, but do this as a second step after the hull flange/deck junction is all done.  I use Plast for the whole long hull flange to deck junction.  Be sure to drill the holes in the deck for the mast ram as well as matching starter holes in the keel box.  You will need these for clamping the deck to the keelbox when you glue the deck on.

So, now quickly apply a moderate (not thin) amount of Stabilit to the top of the keelbox (and if so planned, to the bow reinforcement) and a similarly moderate stripe of Plast to the whole long hull flange and to the bottom of the deck where the two will mate. Press everything together as previously practiced, then quickly apply all of your masking tape strips and screw the deck to the keelbox with the two little mast ram screws.  I let it dry like this for 12 – 24 hours, deck side down to avoid drips.

Remove the tape.  Check carefully that all areas are bonded well.  It you find areas where the flange moves against the deck when you squeeze the hull together, fill these with Plast and allow to dry.  Don’t use too much or you’ll melt the gunwale.  After everything has been dry for a day or two, I apply a ring of thin CA glue all around the gunwale to assure that all is well glued.  Ralf and Jack don’t bother with this, since their work is of higher quality initially.

After the gunwale has been dry for over 24 hours, glue the rear quarters and transom with Stabilit.

You will note that on the v1 that the hull sticks out about 1 mm

DSCN0136.jpg Caption: “Gluing the transom”

further than the transom.  On the v2 it’s more like 3mm.  Almost everyone sands the v1 flush.  I have psychological issues with shortening waterlines, so I left the v1 step intact, tiny as it was.  On our v2, the hull was about 3 mm longer than the transom.  We left this in place. Think of it as a scale swimming platform.

 

 

 

Rudder Post

Getting the rudder post exactly right used to be an adventure, but I’ve changed my ways.  Put the keel fin in place.  Don’t force it in!  Rather sand it until it slides in easily but snuggly.  Now insert the rudder into the lower deck hole, position it both carefully fore and aft and starboard port and mark where the rudder shaft contacts cockpit.  Drill the hole for the rudder tube, insert the tube, and check if it’s perfect.  It will be about half of the time.  If it’s not, simply enlarge the top hole to about 10 mm.  Take a 15 mm square piece of 0.3mmm CF plate or an old credit card, and drill the hole for the rudder tube.  Position it exactly perfect, and glue in the plate with Stabilit.  When dry then glue in the rudder tube, also with Stabilit.  I got the v1 perfect the first time, and I needed the plate for the v2.

Sand & Paint

Now wet sand the hull with 400 grit, then 600 grit paper.  If you’re like me, you’ll have a couple of glue drips.  Carefully wet sand these away with 220 first, but be very cautious to not take too much hull with the glue.  Getting the hull and fins very smooth is really important.  RC-sailboats, because of their small sizes and lower speeds, keep laminar flow much longerthan full sized boat.

Now paint the boat with spray enamel and allow to dry for maybe a week.  Then wet sand again with 400 and 600 grit paper, even 1200 or 1500 grit if you’re interested.

On to the keel fin and bulb and rudders

There’s not much to it, except that you need to work precisely.  Most of the fastest boats use mark 1 fins and mark 2 bulbs.  (Mark 1 refers to a now extinct version of MM and mark 2 is the same as a current v1.) You’ve got a mark 2 bulb already, but you’ll need to order the mark 1 fin.  Currently Graupner USA does not (yet) carry these, so you’ll need to order one from Europe.  Whether you plan to use a mark 1 or 2 fin, it is a good idea to use a mark 1 rudder.

First, weigh the keel fin and bulb together.  You’ll want to be less than 415 grams.  The maximum is 420 grams and you’ll add a little weight in construction.  Now, measure the distance from the front tip

DSCN0133.jpg Caption: “Getting the fore and aft positioning correct.”

of the bulb to the front edge of the fin.  Shoot for 26 mm.  It has to be more than 25 mm.  If you need to lengthen the slot in the bulb, this is easily done by drilling into the area you need to remove with a drill the same diameter as the slot.  Then extend the slot using an xacto knife.  Now, check that the maximum depth is correct.  Shoot for 134 mm, the maximum being 135 mm (measured from where the fin exits the keelbox to the bottom of the bulb. If the bulb slot is all shiny and flat, roughen it a little with a file or some coarse sandpaper. If you need more depth, insert a toothpick into the slot below the fin.  If yo

DSCN9998.jpg Caption: “Checking for proper depth”

u are using a mark 1 fin in a v2, note that the v2’s keelbox is slightly shorter than the v1.  You’ll need to trim a couple of millimeters off the top with an xacto knife and sand a little off of the aft edge of the keel insertion.  You can use your own mark 2 fin as a guide for this.

 

 

DSCN9990.jpg Caption: “Getting a proper perpendicular on the keel fin”

 

 

 

 

 

 

 

DSCN0003“Measuring for proper bulb cant.” (DSCN0003)

 

Applying epoxy to the bulb (DSC00373)
Applying epoxy to the bulb (DSC00373)

 

The finished keels (DSC00655)
The finished keels (DSC00655)

 

 

 

 

 

 

 

 

(Not Available) File:  DSC00628.jpg Caption: “Jack’s keel and rudder. Developmental work, but very pretty!”

IMG_3304.jpg Caption: “Ralf’s keels. The German MM class does not follow the international rules. Rather, they allow multiple keels of different weights for different conditions.”

 

 

 

 

 

 

 

 

 

 

Using a small hammer tap out any larger irregularities in the surface of the bulb.  No need for perfection.  Do not sand the lead bulb itself.  Draw a line carefully from the forward to the aft bulb tip on the side of the bulb.  You need a true perpendicular on the keel fin.  This is not so simple.  Watch a Micro Magic go up wind.  It is actually slightly bow down.

Here’s how to get a perpendicular: Put a mark just above the round area at the bottom of the bow (see picture).  Put the boat with the keel fin in place in the stand and carefully reposition the boat until the distance between the mark and the table and the bottom of the center of the transom and the table are exactly the same.  Now draw a perpendicular on the fin using a right angle. Remove the fin. Put it into the slot on the bulb and measure the angle between the two lines with a protractor.  Even though the two lines are not exactly in the same plane, it is easily possible to measure the angle within a degree or so.  According to a previous Model Yachting Theory and Practice article, you are shooting for 87-90 degrees, but absolutely not less than 87 or greater than 90.  Cocked way up or down is slow.

If your total keel weight (see above) was less than 410 grams and you extended the slot in the bulb to move the fin forward, buy some lead split shot as is used in fly fishing at your local fishing store and tack glue this in place in the excess slot with some thin CA glue.  The last step is easy:  glue the bulb to the fin with a little bit of Stabilit.  No need for a jig, just hold the bulb to the fin at an 87 – 88 degree angle with your hands until the glue sets up (about 10 minutes).  This sounds hard, but it’s as easy as can be.  Next, fill the slot with Stabilit up to the top of the slot and allow to dry.  Get some cheap, clear epoxy at the hardware store along with the cheapest little brush that you can find.   Paint the bulb with the epoxy, including the bulb – fin junction and put the keel fin in a vice with the aft bulb tip pointed down.  The excess will drip off of the bulb tip leaving you with a very smooth bulb with a sharp tip at the aft end.  Let dry for a couple of days.  Then wet sand the bulb with 220 grit until it is totally smooth and even.  While you are at it, round the forward edge of the fin and the rudder a little.  Both are way too sharp as they come in the kit.  Fill any irregularities with modeler’s putty.  Sand with 220 grit and very lightly spray with whatever color you plan on painting the keel.  I suggest a very light color so that you can see attached weeds from a distance.  The paint allows you to see irregularities better.  Repeat the sanding and filling until all is perfect.  I always plan on two iterations, but usually need three or four.  Lastly, wet sand the keel and rudder with 400 grit, apply the finish coats, and after 3-4 days, wet sand with 400, 600, and if you want 1500 grit.

Servo Install

Install the servos.  Not much new or fancy here. Obviously, bolt the sail servo onto the mounting plate and screw the plate onto the keelbox with wood screws.  Screw in the rudder servo with wood screws.  Otherwise, you’ll have future trouble replacing them.  No need to mount the sail servo arm yet.  Jack and Ralf both mount their receivers on the starboard forward area of the sail servo mounting plate.  I mount mine on the port underside of the deck immediately adjacent to the keelbox.  Likely not much difference here functionally, both methods seem markedly preferable to the usual method of sealing it in a pill bottle or plastic bag and then velcroing to the side of the boat.  You’ll note that I used positive arms for rudder control.  I had felt for a long time that the standard pull-pull system on stock v1s was actually preferable, being lighter and more gentle on the rudder servo.  Jack agrees with this, as you’ll see i

A Z-spring on the rudder push arm (DSC00671)
A Z-spring on the rudder push arm (DSC00671)

n the pictures.  But Ralf’s single arm method is really slick, and I used it in both boats.  The main point is that the Z-spring makes it obvious when the rudder is hanging up, and you can look into it easily and promptly (even easier than the standard pull-pull system).  Also, Mike Eades had reported frozen junctions on single arm systems blowing rudder servos.  If you look carefully, I devised a simple no-freeze system.  When you mount the rudder, check it out carefully with the transmitter and sail servo to assure that you’re getting unimpeded movement through the entire range of motion.  This is really easy to see if you watch the rudder and the Z-spring together.

 

Jack’s modified stock rear brace and steering set-up. (DSC00472)
Jack’s modified stock rear brace and steering set-up. (DSC00472)

 

 

 

 

 

 

(Not Available) File: IMG_3276.jpg Caption: “Ralf’s boat doesn’t use a standard rear brace. Note the ABS rear strut braces instead. I did the same thing on the v1 and v2 except with 4mm CF tubing.

 

I was going to build one boat with an angled sail servo arm (in order to preferentially ease the main before the jib), but I ditched that when Dutch champion Elmer Boon scolded me to keep it simple, stupid.  (See the great interview with Elmer elsewhere in this issue.)  So, we’re running dead stock with the sail servo arms.  You can get a little of the “let the main out first” geometry just by bringing the jib sheet block in a screw hole or two.  That’s a marginal change, though.

To the rig

Since you have already joined the AMYA and sent in your boat registration to me, now is a good time to put the numbers on your sails.

Build the Mast

Then build your mast:  Jack (Mr. Reynold’s Number) uses nothing but 5 mm masts.  I have used both stock v1 five mm masts and Skyshark 2Ps (slightly more than 6 mm diameter).  The v2 comes with a 6 mm mast with 4 mm extensions on each end.  It was a good bit heavier than either the stock mark 1 or Skyshark masts, so I did not use it.  I put a stock v1 five mm mast into the mark 2.  I use tiny 1mm cotter-pins instead of the stock plastic piece for the jib-stay attachment and 2 pieces of 1mm CF rod for the mast crane.  Jack modifies the stock plastic pieces to the point of unrecognizability.  See the photos.  Don’t cut the bottom of the mast for length yet, but do fashion a 6mm diameter shim for the bottom of the mast using either the stock aluminum tube that comes with the v1 or an old left-over piece of 6 mm mast.  This should be cut to extend a mm or so above the top of the gooseneck.

DSC00386.jpg Caption: “Superlight masthead crane and jib-stay attachment.”

 

IMG_1990.jpg Caption: “Jack’s masthead crane and ball-bearing wind vane”

 

DSC00633.jpg Caption: “Jack’s gooseneck, strictly developmental, but very cool”

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(No photo) File: DSC00633.jpg Caption: “Jack’s gooseneck, strictly developmental, but very cool”

DSC00635 .jpg Caption: “Gooseneck as described by Elmer Boon”

 

 

 

 

 

 

Goosenecks and Vangs

Jack built a work of art of more than questionable legality, but a work of art nonetheless.  Actually, his boat is very much a developmental boat, he really isn’t very much concerned with legality.  If you see him at a regional regatta, you will likely note that he’ll be racing the v1 boat that we’re building here, not his developmental boat pictured here.  In the picture, you’ll note a stock VAM ball bearing gooseneck, an example of the typical Azura ball bearing goosenecks, and our best try of mocking up the gooseneck described by Elmer Boon in his article.  Pick which you like best.  The Azura design is from one of our ancient Keith Molen/Punta Gorda boats. The Azura gooseneck is made of a 20 by 52 mm piece of 0.40 mm (0.016”) aluminum plate bent around two sealed 6mm internal diameter bearings and glued with epoxy.  Don’t forget the little cotter pin.  This is used for the downhaul which leads to a piece of surgical tubing on the main boom.  The boom a la Boon is a chopped-up stock gooseneck and glued to a piece of credit card or 0.3 mm CF plate.  The idea here is that the boom stays in place for multiple rigs.  Note the little hook on the downhaul for quick rig changes.  Note that if you have the downhaul coming through the fixed piece of the gooseneck, you will need to trim it to the deck and if it goes on the boom side of the turning axis, it will need to be trimmed on the main boom.

Booms

I have always used 4mm job and main booms.  Jack’s boat has them, too.  VAM booms are made of Skyshark 2P.  Elmer thinks that larger booms function as endplates.  I am skeptical about this claim (not

DSC00646.jpg Caption: “Three types of booms”

that endplates aren’t a good idea), but willing to give this a try, hence the 6mm main and jib booms on the v2 boat.  In my endeavor never to use any stock Graupner parts, I fashioned the main boom to gooseneck junctions from left-over servo arms.  This works great and is easy.  Ralf use stock jib boom counterweights, predictably, Jack uses a markedly modified one.  I use custom ones made from 4mm brass rod.  These look cool and are very quickly made with a dremel with a cutting disk and a drill press.  For a 4 mm boom use a 32 mm piece of rod, and turn down a 10 mm piece at the end to 3 mm to insert into the boom.  For a 6 mm boom, make a 10 mm shim out of some 5 mm CF tube and simply insert a 32 mm piece of 4 mm brass rod into it.

Rigging

I use 20 lb. Spiderwire for everything except the jib boom to deck eye loop which is 80 lb. Spiderwire.  Jack uses 20 lb. Spiderwire for some stuff and 5 lb. for the rest. (Note that this is not a typo.)  Ralf fainted when he read that last sentence and hasn’t been heard from since.  I hope that he is recovering well.  I use 3mm internal diameter silicone tubing for 4 mm boom sliders, and 5mm silicone tubing for 6 mm boom sliders.  Both Jack and Ralf use many more Graupner connectors, in Jack’s case always highly modified.  Ralf likes little metal hook sliders made of piano wire for the tacks and clews.  I tie mine out of Spiderwire hoping for more flexibility.  I avoid bowsies like the plague in the wind stream, and when use the tiny stainless steel ones.  I use 1 mm CF rod for my forestays.  Ralf uses a more standard luff wire.

DSC00672.jpg Caption: “1mm CF rod is used for the forestay. This is connected to 20 lb. Spiderwire as shown.”

 

DSC00673.jpg Caption: “Jib sheet bowsie, the simple way”

 

 

 

 

 

 

 

 

 

 

 

 

(No photo) DSC00669.jpg Caption: “Jack’s extremely developmental, but also extremely interesting rig.”

Lastly, note that both Jack and Ralf use trick outside adjusters for both the main and jib sheet.  I use a simple internal bowsie on the jib sheet only.  I adjust the main and jib together with the transmitter trim adjustment, and use the internal bowsie only to adjust the slot.

Sails

The stock v1 sails are fast, so I used them.  The newer v2 sails are much improved from the original v2 sails, but the material is still quite heavy, so I used sailmaker sails on the v2.  The simplest way to get the proper mast height is to tape the head of your mainsail ¼” below the bottom of the masthead crane and cut the mast such that you get about 1/8” of downhaul adjustment.

Batteries

There are 3 good choices.  You can use NiMh AAA 4 or 5 cell battery packs.  These are ~700 mAh.  The 4 cell pack weighs 51 grams, the 5 cell packs 64 grams.  HobbyKing makes a really nice 700 mAh LiFe battery. It is 2 cell (2s) and weighs 55 grams.  Since it has 2 cells, it requires balance charging, but this is not really a big deal after you get used to it. It is 6.6 volts.  This is not too much for the servos.  Lastly, if you have a boat which is over the 860 gram minimum weight, consider cell phone batteries from HobbyKing.  These are single cell LiPOs, implying 3.7 volts and no balance charging.  The 3.7 volts works fine with most receivers.  They are 600 – 750 mAh, and almost magically they weigh only 15 – 20 grams.  You do have to solder the connector wires on yourself and you have to know how to figure out which is the positive pole. (Both tasks are easy.)  We use them routinely at Azura.  We package them in little ziplocks and tape watertight with strapping tape. They do have the disadvantage that some of them swell with gas after 18 – 24 months.  When this happens, they should no longer be used and they should be disposed of properly.

DSC00674.jpg Caption: 3 options for batteries. Note that some skippers also use 5 cell NiMh AAA packs.

File: DSC00674.jpg Caption: 3 options for batteries.  Note that some skippers also use 5 cell NiMh AAA packs.

DSC00684.jpg Caption: “Casciato is the v1. She weighs 826 grams, implying that she’ll need 34 grams of lead to make the 860 gram minimum weight.”

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Not Available) File: DSC00686.jpg Caption: “Pumpkin is the v2.  Just by chance, she weighs 860 grams on the head.”

That’s about it

All three of us wish you fun with your building and even more fun sailing your new Micro Magic! We really had a good time with this project, and we recommend it to all of you.  The boats are fun to build and come out just great!

Suppliers:

  • Servos – ServoCity, Graupner USA
  • Carbon Fiber Plate and Rod – HobbyKing, Midwest Carbon Fiber, Goodwinds Kites
  • Rudder Fasteners – Tower City
  • Rudder Fasteners – Tower City
  • Ball Bearings – Fast Eddy Bearings
  • Aluminum Sheet – Most hobby shops
  • Goosenecks – VAM
  • Silicone Tubing – Aquarium shops, Amazon
  • Piano Wire – Most hobby shops
  • Keel Fins and Rudders – Graupner.de, RC-Zeilen.nl
  • Goosenecks – VAM
  • European Glues – RC-Zeilen.nl, Conrad.de
  • Sails – Black Magick, Carr, Cat, Ken Bauser, VAM, Sirius

Build a MM – Product – Sails

Summary

This post contains sail prices and will be updated as new data arrives.

The products identified thus far are:

  • Velas

Velas Sails

vamsails@vamsails.com
https://www.vamsails.com
Payment: PalPal
Transportation: 12€ ($13)
Transportation Time: 2 weeks

These sails were identified by Greg Norris, MM Class Secretary, USA.

SAIL A 45€ (about $47)
SAIL B  AND C 35€
SAIL D AND E  30€
GOOSENECK COMPLETED 37€
BACKSTAY CRANE CARBON 9€

(On March 31, 2017 when this data was received the Euro was trading at about $1.07/Euros)

 

Building a MM – Products – Tx and Rx

Receiver

HobbyKing OrangeRx R610V2 Lite DSM2 Compatible 6CH 2.4GHz Receiver w/CPPM

View the product details at the HobbyKing website and then bu
y it from a USA source that you find searching.

A typical price is $12.00 including shipping and a few day delivery.

Transmitter

HobbyKing OrangeRx T-SIX 2.4GHz DSM2 Compatible 6CH Transmitter w/10 Model Memory and 3-Pos Switch (Mode 2)

View the product details at the HobbyKing website and then bu
y it from a USA source that you find searching.

Pricing varies widely but it appears that it can be found for under $100. Watch the delivery time information as it can vary widely, ie, up to two months (likely coming from Hong Kong).

Alternative Tx

There are many transmitter choices on the Internet. You want one that is 2.4 GHz, DSMX/DSM2 compatible. An obvious choice is a radio by Spektrum or Futaba. But there are selections on the Internet at very low prices. Ideally you also want your Tx to support Dual Rate/Exponential. This function is used with the rudder to improve direction control.

I found this radio (Tx and Rx) on the BangGood.com website during a casual browsing: (THE QUALITY OF THIS PRODUCT IS NOT KNOWN). Price about $44 with free shipping.

FlySky FS-i6 2.4G 6CH AFHDS RC Transmitter With FS-iA6B Receiver