By Mike Eades, MM #315
Back in 2015 the new Graupner SJ company had added an RTR version Micro Magic to its product range allegedly based on the “Champ Spec” MM’s built by Mike Weston, UK which incorporated several refinements in construction, one of which I had bought and have sailed successfully for several years. I imported one of the new HoTT RTR versions and built it for evaluation. I compared notes with Ralf Bohnenberger, Germany who agreed with my assessment and fed back to Graupner suggestions for improvements on behalf of the Micro Magic International Class Association.
In late 2016 Graupner USA, through its web site OpenHobby.com, introduced the HoTT RTR version for sale in the USA. This note provides an evaluation of current production which I refer to as the 2017 version.
The shipment, in the customary Graupner blue box, contained a fully finished hull, fin and bulb, rudder, partially rigged mast and booms, a folded card leaf containing sails and a set of decals and an Instruction Manual (Actually in my box there were 5 copies of a Spanish version Manual and no English version. I was able to download and print an English manual from the OpenHobby web site.) The new Instruction Manual is now mainly pictorial and is much improved over the earlier version.
The hull was beautifully finished, painted white with deck and hull well sealed and all components installed except receiver and battery. Several of Weston’s refinements had been incorporated: hatch secured with 5 latches, an extra one at the front, rudder servo offset to provide extra room in the hull, (Figure 1) single steel rod steering arm and rubber boot, main sheet adjustment located in the rear cockpit, flat knob on transom for backstay attachment, (Figure 2) two hooks on deck for jib pivot attachment and 3 position battery location strip. The on/off switch was installed. To complete the hull ready to sail required trimming redundant arms from the rudder servo horn and tiller arm, inserting the fin and bulb and securing with the deck nut, mounting the rudder and adding a battery and receiver.
Reviewing the assembled hull and components revealed several pluses and minuses. The rudder I received was a Mark II model (Figure 3) whereas the earlier version and Champ Spec models used the Mark I rudder, slightly preferred especially in high winds. The fin and rudder were properly aligned and the rudder post correctly located at 210 mm from the aft edge of the fin. The fin and bulb were nicely faired and finished and when installed the depth from base of hull to base of bulb measured very close to the required 135 mm. The earlier version measured 138 mm, any slight discrepancy can easily be cured by sanding down the head of the fin and the rear sloping edge. The set back of bulb from nose to front edge of the fin was correct at 25 mm. However the weight of the fin and bulb was 428 gm compared with the required 420 gm maximum. To meet Class specs I drilled out a hole in the base of the bulb, roughly centered fore and aft and enlarged the hole gradually until 8-9 gm of lead had been removed (approx. 11/32” diameter hole) and filled the hole with epoxy resin/micro-balloon paste (Figure 4). The location of the fore jib pivot hook measured 186 mm from the center of the mast slot in the deck compared with the Class Rules recommendation of 176mm however I understand from Ralf Rosenberger that the MMI Rules tolerate this difference which is also present in several kit built boats. Overall weight ready to sail including a 5-AAA cell 1000 may NIMH battery and a Spectrum AR6100e RX but without the rig was 880 gm. Finally, while the sheet lines were installed and attachment hooks loosely tied but not placed correctly, the line used was quite stiff and not really suitable. I replaced both sheet lines with 50 lb. Spectra fiber line.
The rigging components and philosophy were a mixture of standard MM Racing kit design (standard Graupner gooseneck, deck plate and mast crane, Cunningham adjuster attached to one of the shroud attachment eyes and use of sliding collets on booms for some adjustments) with some of John Tushingham’s “Graphite” rig design elements (use of silicone ring sliders for adjustments, attachment of the jib forestry and topping lift to a small metal ring attached to the jib hangar to ease jib rotation. The mast appears to be a 3-piece construction with a 6mm OD carbon spar from just below the deck plate to the jib hanger and two 5 mm OD carbon tubes at either end. Shrouds are included but are redundant, on my model I used the cut off shrouds for my jib pivot and Cunningham lines which were missing. One annoying feature of the standard Graupner gooseneck has always been the tendency for the gooseneck fitting to slide upwards along the mast allowing the two locating tabs to slip out of the deck plate thus allowing the fitting to rotate around the mast. I devised a simple cure by marking the mast just above the gooseneck when correctly located in the deck plate and winding a collar of Spectra fiber fishing line around the mast just below the mark and saturating it with thin CA glue (Figure 5). Now, when in position the collar maintains downward pressure on the top of the gooseneck preventing it from being lifted out of the deck plate (Figure 6).
The sails are of improved material over the earlier version, white Icarex, but still perhaps slightly heavier weight than desired for “A” sails. Construction however was poor with a large triangular joint half way up the main sail and wrinkles near the main sail head (Figure 7). I assembled the rig essentially as designed for evaluation including use of the metal luff rings.
The finished all up weight ready to sail was 932 gm, still somewhat high. However Greg Norris informs me that substituting a lighter LIPO battery could reduce the weight to 880 gm which would be very much in the competitive range.
I conducted some brief sailing trials against my usual local competition and found the boat performed well, even in light air. I conclude that with a few minor improvements the ARTR version Micro Magic will be an excellent addition to the product range providing new skippers, who don’t want to build from a kit, a competitive boat for racing.