John Tee Posted July 13, 2022 Share Posted July 13, 2022 I am relatively new to gliding having been flying a Radian motor glider for a few years. It virtually flies itself. I have now "upgraded" to an FMS FOX V2. It is taking a bit of sorting but slowly getting there. I have a query with the COG as per the instruction sheet. Each wing panel is 1235 mm long, 235mm at the root and 95mm at the tip. The leading edge is straight so the taper is all on the trailing edge. The suggested balance point is 40 mm behind the leading edge at the root which to me looks too far forward. Anty suggestions please as to whether the cog is correct. John Quote Link to comment Share on other sites More sharing options...
John Minchell Posted July 16, 2022 Share Posted July 16, 2022 John do not fly this model with the original white folding propellor blades, even the revised ones can snap across the root pivot point. Pal of mine had it happen and the out of balance forces ripped the motor out of the firewall actually shearing the aluminium mounting and the ply bulkhead. Twisted up all the 3 wires up to the ESC and pulled that forward out of its velcro mounting in the time it took him to close the throttle. Luckily the bec wire was still attached to the Rx and he could land as a glider. The canopy was popped off 1/2 a mile away when it happened due to the twisting of the fuselage. Took us half the day to find it in the next field. Also it took FMS 5 months to replace his damaged fuselage and I advised him on some quality prop blades which are carbon and will not shear across the pivot holes. HTH John M 1 Quote Link to comment Share on other sites More sharing options...
John Tee Posted July 16, 2022 Author Share Posted July 16, 2022 Mine has a black one!😃 John Quote Link to comment Share on other sites More sharing options...
John Minchell Posted July 20, 2022 Share Posted July 20, 2022 JT, All the same I would be inclined if it were mine, to put a Graupner Cam, Aeronaught or other quality prop or even splash out on an RFM for peace of mind. Up to you of course. Quote Link to comment Share on other sites More sharing options...
John Tee Posted July 20, 2022 Author Share Posted July 20, 2022 Thanks I will look into that. Any comments on the CG? John Quote Link to comment Share on other sites More sharing options...
John Minchell Posted August 10, 2022 Share Posted August 10, 2022 Been ill so sorry for the delay in replying. Not my model, but he says the CG is as per instructions and is ok. However he is one of the best pilots I know and can fly anything and very well too. Quote Link to comment Share on other sites More sharing options...
MattyB Posted August 10, 2022 Share Posted August 10, 2022 A quick Google indicates somewhere between 43-50mm back is what others are using... https://www.rcgroups.com/forums/showthread.php?2360052-FMS-Fox-Glider-V2 TBH on a dead straight wing like this I would jsut use one of the many good calculators online, they won't give you the perfect position (only flight testing does that) but they will always get you close enough to validate if a manufacturer has made a mistake or not... https://www.ecalc.ch/cgcalc.php Quote Link to comment Share on other sites More sharing options...
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