threedee by Scorpio

29 Dec 11 - Motor replaced

N of launches / Time 33 6 hour 32 mins
Wingspan 36 " 92 cm
Wing Area 303 in 19.5 dm
Flying Weight 1 lb. 7 oz 650 g 1 lb. 6 oz 630 g
Wing Loading 10.9 oz / ft 33.3 g/dm 10.6 oz / ft 32.3 g/dm
Wing Cube Loading 7.5 - just above a "Trainer" 7.3 - just above a "Trainer"
Motor

Typhoon 15 brushless (High-End Technology)

KD A22-20L 1000 RPM/V Brushless Outrunner Motor
Propeller APC-E 10" x 5"  
Batteries 3S 1800mAh Shark Power 20C LiPo (36A max.) or 3S 1800mAh FlightPower EVO20 20C LiPo
Speed Controller

Hacker Master 30-3P - 30A - 6 to 10 cells - BEC & Brake - Programmable cut-off voltage

Receiver / Battery Webra Nano S6 - 6ch - PPM - 35 MHz
Servos Ailerons - 2 x Hitec HS-56HB
Elevator - Hitec HS-56HB
Rudder - Hitec HS-56HB
Static motor parameters  25.3A (14C) @ 9.9V giving 9150 rpm, 250W and approx. 180W/lb.  Thrust is calculated at 1185g (41 oz.).  
Flight performance Vertical climbs completely effortless, although the model likes to go offline in the climb. The model can now complete almost all manoeuvres except knife edge (too little rudder authority)  

25 May 09 - Whilst flying yesterday the motor failed.  I've stripped the motor and the rear bearing and stator can wobble side to side, allowing the magnets to touch the stator.  I'm not sure exactly what has happened as it's difficult to see and I can't work out how to disassemble the motor further.  It looks like I'll have to find a replacement motor.

14 Mar 07 - I have been suffering occasional spells of flutter, which I have narrowed down to the hatch.  I will have to add some stiffening to it to prevent recurrence.

9 Sep 06 - The model has been modified by fitting a hatch in the underside of the fuselage and to take a 3S Shark Power 1800mAh (20C) pack.  This meant re-bending the undercarriage legs, to go around the pack, which means a narrower track to maintain ground clearance.  I also decided to replace the Ramoser Technik & Design VarioPROP with an APC-E 10" x 5" propeller as it is a lighter solution.

3 Dec 04 - I fitted the 3S Kokam cells some time ago and decided I really should update this page. The weight increase due to the new page is only about 5g (0.17 oz.) and therefore negligible. The power to weight ratio, however, has increased by 58% with the loss of 33% of the original battery capacity. The model now leaps off the grass and will climb vertically almost without limit. I measured the thrust the propeller produces and it is 960g (33.9 oz., giving a thrust to weight ratio is 1.46:1 - pretty damn good.

18 Jul 04 - Just completed the model and checked it through. I am thinking of getting a 3S pack of the new 2000 mAh cells (15C) which will be heavier but give more power due to the increased voltage and current sink capability (30A max.).

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