Performance Evaluation Wanted
To convert the Wing Mfg A-26 I elected to use two Gary Wright Endoplasma/GP Gear Box systems to power the plane. MotoCalc claims the configuration should work well. So here is the results:
MotoCalc estimates the thrust would be 112.7 oz. I measured 64 oz! To measure the thrust I set the plane tail first on my digital scale and had two friends gently balance the plane. Under full power the plane weight decreased 4 lbs. Not the seven (7) MotoCalc estimated.
So my questions are; Do you believe MotoCalc, do you think my thrust measurement is valid, what would you do to check for problems in my configuration?
System info:
Motor: Kyosho EndoPlasma 16T; 3785rpm/V; 2.5A no-load; 0.022 Ohms.
Battery: Sanyo HR-4/5FAUP; 10 series x 2 parallel cells; 1800mAh @ 1.2V; 0.006 Ohms/cell.
Speed Control: GP- C-50; 2 controls (separate); 0.003 Ohms; High rate.
Drive System: Great Planes Gearbox 4.6:1 3-Blades; 2 motors (parallel); 11x7 3-bladed (Pconst=1.11; Tconst=1) geared 4.6:1 (Eff=95%).
Airframe: A-26 EndoPlasma; 748sq.in; 147.6oz; 28.4oz/sq.ft; Cd=0.048; Cl=0.46; Clopt=0.6; Clmax=1.11.
Stats: 70 W/lb in; 56 W/lb out; 26mph stall; 36mph opt @ 73% (16:01, 123°F); 41mph level @ 82% (13:12, 129°F); 963ft/min @ 17.7°; -309ft/min @ -5.6°.
Your help and ideas will be appreciated.