Could not resist buying the Panther for Xmas but I have bought the bits i.e. fuselage, wings, tail, landing gear and some clevises. It is going to be a bit experimental using FMS 64mm 11 blade edf, 1800mah Turnigy nanotech plus 4 s 70c battery ( 215gms ). I am increasing the wingspan by 100mm adding inboard extensions and flaps . might add rudder using 9gm servo 01.6kg-cm torque , servo calc recommends 0.14kg-cm for 100x30mm rudder, 70mph 25deg deflection so little weight penalty. Easiest way to do this is join the 2 elevator halves into one with cf flat then use the spare rod tube to install rudder controls. Additional wingspan gives me better wing loading for flaps and rudder with all up weight at 835gms and 67gms/dm2 wing loading . Fms 64mm fan, 40 amp esc, 1150gms thrust ( bare static ) so should get near 1 to 1 actual which will be fine for my grass field. I have removed a chunk of the battery tray to get battery as far forward as possible and while I await the arrival of the fan I have added fly screen to cheater fan holes underneath, turned the canopy black on the inside, carved out some foam and directed the air inside opening up the front canopy window to provide esc and battery cooling and additional input air for the fan all in one go. I will post more photos as I progress.
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Official Freewing 64mm EDF F9F Panther Thread
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Panther Progress, joined the 2 elevator halves together with 6mm flat carbon fiber top and bottom, cut out small amount of foam to allow free movement, rudder ready to fix, note notch to avoid elevator cf joint. also note elevator control on port side to ensure rudder works correctly with nose steering.
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Originally posted by rifleman_btx View PostThe only thing that I didn't like with this one was the lack of rudder. I'm wondering if the weight of adding flaps might hamper performance. This is definitely a build I'm looking forward to seeing complete.
Panther
Fuselage 180g
Wings 056
Tail 037
Front gear, servos, oleos etc 040
Mains gear 030
2 ail hxt900 servos 020
1 10g fms servo elevator 011
2x5gm hk 1440A 010g flaps 35mmx140mm with max def 40 deg torque calc ok
Rx & 40a esc 051
18004s nanotech plus 215
Wing extensions 035gms incl flap hinges , wire and clevis. 4mm cf rod.
FMS 11 Blade 4s Edf unit 135g 1150gms thrust.
Total 820 plus 20gm glue
Say 840gms . Calc with 50mm wide wing extensions ( I think enough to get away with it visually finished in yellow and providing solid base for mains u/c which I will move forward closer to cg to assist take off ) i.e. wingspan 785mm =12.86dm2 = 65.5 gms/dm2 . fms 64mm 4s 11 blade unit , mock up using 3s freewing edf with ballast to get 135gms shows can do it without additional ballast by moving esc and edf and servo and battery positions and achieve cg 35mm back from LE, will weigh again when complete. adding the inboard wing extensions helps with the weight/wind loading issue which will be very similar to Arrows Marlin at 66gms/dm2. Thrust to weight 1.39 to 1 static, allow 30% drop on static thrust gives 805g thrust, 840gm model pretty close to 1 to 1 so should be ok off grass. EDF is same as Arrows Marlin which weighs over 1000gm, I guess we will find out when its all done don`t hold your breath it could be few weeks before edf gets here on slow boat from China.
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Panther wing extensions setup. Balsa flat sections epoxied to outer wings first after propping up tips to suit. dry fit wings with cf tube, create and check temporary tip supports , check measure horizontal stab distance equal at tips from building board surface., put gorilla glue in cf holes of outer wings and on cf tube then epoxy balsa to inner wings, pin and check inner and outer wings distance off deck at front and back, set aside to dry overnight before finishing off wing formers to take 1.5mm thick balsa skins to top of balsa wing extensions, followed by finishing off flaps, hinges, installing flap and aileron servos, final supports for main gear , 1.5mm balsa bottom skin and then matching self adhesive printers vinyl sheet finish and silver paint touch up to Wing leading edge.
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Originally posted by Gilatrout View PostLove the work.
Last edited by paulrkytek; Dec 31, 2021, 11:10 AM.
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Freewing Grumman F9F Panther . original 685mmm span, modified 800mm wingspan 860gms all up take off weight. Wing area of 12.86dm2 = 67 gms/dm2 . 1.15kg manufacturers quoted thrust = 1.45 to 1 at 860gms. FMS 64mm 11 blade edf unit, 2840 3150kv out-runner, 135gms, 40amp esc, 1150gms thrust, 1800mah 4s 70-140c lipo(215 gms). Recalculated cg for modified wing with 15% static margin is 48mm back from LE of intake, set to 38mm back for maiden flight. Modified version has inboard wing extensions with flaps, rudder and sprung nose wheel. Mains wheels repositioned closer to cg. Fod guard to cheater fan, blacked out canopy with open front window to cool battery, esc and make up for fod guard air loss. Ordered fms edf unit to replace duff X-fly unit so it will be February before maiden.
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FMS fan now installed, It is ready for maiden flight, now waiting for replacement lipo, I bought 2 1800mah 70c 4s Nanotech plus lipos, one arrived with one cell down, had to jump through hoops to get warranty return authorised, the chances are they have run out of stock so the wait goes on
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First 2 flights on the Panther today off our newly cut grass field, half flaps take off, eased off the ground after about 30 metres, good climb out, throttle back to 1/2 power, bit of right aileron trim, touch of elevator trim, just 2.5 mins flight, 45% battery left on checker, landing on full flaps, minimum power, no problem. Very happy, the extended wings worked fine, flaps fine, rudder a bonus worth having. Smooth flyer, no bad habits.
Paul
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Originally posted by paulrkytek View PostFirst 2 flights on the Panther today off our newly cut grass field, half flaps take off, eased off the ground after about 30 metres, good climb out, throttle back to 1/2 power, bit of right aileron trim, touch of elevator trim, just 2.5 mins flight, 45% battery left on checker, landing on full flaps, minimum power, no problem. Very happy, the extended wings worked fine, flaps fine, rudder a bonus worth having. Smooth flyer, no bad habits.
Paul
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Originally posted by Marko the jet guy View Post............ The plane is now done except for some gray touch ups on the fuselage. The wings are still yellow but the plane did gain quite a few square inches of area. The CG was also moved back a bit due to the sweep angle. The plane balances very well with an 1800 3S pack on the tray. I will get the touch up done this week and perhaps if the weather gods up here in the New England are good to us we will do some test flights next weekend. Here are some pictures of the transformation.
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