Kyosho ARTF Spitfire electric conversion
First flight sunday 12th August 2001.
An easy conversion from the original ARTF kit designed for a 2 stroke 40.
I inserted a platform to support the battery pack, shaped so the front can slide into a slot cut in the firewall. The pack is held in place by a second ply plate to which the two seven cell packs wired in series are attached with cable ties and separated by balsa strips to aid cooling. This slots into the firewall and has a small captive bolt that comes through the first platform and is secured by a nylon lined nut.
The motor mount is very straightforward the way I did it, having messed around with various mounts on the firewall ( very difficult to move the motor far enough forward and line it up with the cowl) I noticed the cowl is beautifully moulded in tough fibreglass. I therefore ditched the motor mounts and treated it just like an electric glider, whilst adding two vertical pine strips either side of the firewall to securely screw the cowl to. Works like a dream and has enabled me to line the spinner up perfectly.
The retracts are Graupner type 94 mechanical driven by a Hitec servo, both fit perfectly, no hassle and well worth it in my view.
Other servos are HS 85 in the wings and HS225 for rudder and elevator.
Motor is a Mega Brushless 22/30/4 with 14 Sanyo 2400 cells and a Jeti 40 Opto controller, I have used a Hitec Super Slim 7 channel PPM receiver. The prop is an 11x6 Cam prop and at full power on a fresh charge pulls about 40 amps and 10,700 rpm. That makes about 100w/lb which makes for excellent performance. Flight times of around 7 minutes.
All up weight is 2,85 Kg (6 lbs 4oz), about 400 gms (14oz) more than the glow version with a 40 2-stroke. The wing area per Kyosho is 36,5 DMē (56,6 sq in)
I am absolutely delighted, excellent take off from a grass strip, the retracts work fine and the performance is excellent. I didn't try anything fancy, but it is clear that this is going to be a favourite. Precise controls, not too fast (quite a thick wing section) , this bird will really hang in the air. I wanted to try a stall test but chickened out when almost standing still, must try harder !Only hiccup is on landing, twice now I have tipped the plane on it's nose. Undignified (particularly when being filmed) no damage though. I suspect I can resolve this be better technique (slower, and on all three wheels), if not I may put in larger wheels but this would mean some more surgery on the wing and I am not keen.
I will be doing a bit more cosmetic stuff, and lots more flying!
I suspect all of this Kyosho series are good candidates for conversion.