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Aug 28, 2002, 12:17 AM
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71in J3 Piper Cub Conversion take off.....Yes!


Black Horse Piper Cub J3**Same as the Graupner Piper Cub in HL site
Span 71 in
Area 700 Sq
AUW 7lbs
Motor Mega 30/3 with Graupner Belt 2.5:1
Prop 12x7
Estimated AMP: 27amp @ 450watts
16 RC2400
Flight time about 10 mins.
Loading: 23oz

Lighten some part by drilling the swiss cheese holes on the fuse. Also remove the fuse and wing lower panel covering. That reduce some 5 oz. The plane come with all the HW and I use them all except the engine mount. Some cooling hole for the firewall and reinforcement on the wing joint area, and some modification for battery mount and Iím done.

First flight was scary hairy. I forgot to pull up elevator to keep the tail on the ground. It topple over in less than 10 feet run. Clean up the sand and ready again.

Rudder control was good and after awhile, tail came up and off she goes. It was head heavy so I need to hold the elevator up until my buddy trim it for me. I canít even let go of the stick. It just nose down. With no headwind, it take off in about 60 feets. It take off with elevator low rate, about 1cm throw. I adjusted the CG slightly rearward when I reached home.

The flight was graceful. Climb was good, say 30 degree and flight speed is decent say 40mph. Putt around and its flight truly scale. However the plane have pretty bad adverse yaw. Differential help a bit plus the coupled rudder. So with less than 70watts/lb it still flew well. Maybe of its size and speed, I always felt that it will stall. But at any time with the motor on, it will maintain its altitude. BTW, I also use the standard servo for Elevator and rudder. HS81 for the aileron. I could save another 2 oz there. But it fly! And I can cruise around on Ĺ throttle. Thatís probably around 16-18amp. Landed after 10 mins flight.

Landing was no event. I line it up far and maintain the low altitude approach and as it about to touch down, I flare the elevator and the front wheel touch down first follow by the tail, so pretty scale if you ask me. For grass landing, I will go for tail touch down first .

I converted Air Combat Spitfire 2 weeks back. That one on Kyosho MM with 10 cell. AUW 4lbs, and its fast with 300watt. Funny though the loading almost the same as my cub above.


Thanks for reading! I know the cub has been converted to death, hope this did not bore y'all.
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