| Prototype Fairchild A10 "Thunderbolt", 65 inch WS, powered by two SC 0.32 engines driving 9*6 props. This is an own design developed on Autocad from a scanned 3 view magazine illustration. (see more Photos below ) |
The expense of two ducted fan units and the problems of incorporating fuel cells in such small engine nacelles prohibited the initial desired design, so twin tractor units were used. The use of a data base I developed in Excel determined that 19 ozs of lead weight was required in the nose to apply the correct CG. The total weight worked out at 8.5 lbs pushing the wing load up to almost 30 oz/sqft giving me concerns about takeoff and landing speeds. I decided to build in flaps/airbrakes and set each aileron about 4 degrees up (in the neutral position) to hopefully add to the 2 degree washout already built into the tips permitting (gulp) slower landing speeds.
After setting and trimming the engines taxiing trials proved to be very encouraging, the power from the two 0.32 engines was pleasantly surprising, indeed a lot of elevator down was needed to prevent what appeared to be an eager desire to get airborne.
So the time had come for a maiden flight, having never flown multiengined craft before, I conscripted the services of George, our club instructor, did I hear you say "chicken", well your correct so there. Just as well since on the second circuit the port engine cut but by reducing throttle the remaining engine handled the situation quite well (without the aid of rudder) and was landed nicely straight down the middle of the strip. After retrimming the engines the subsequent flights allowed George time to assess and trim the craft, suggesting a much reduced throw on the elevator. All his recommendations, although minor, were implemented.
The next few runs involved testing the flaps on takeoff and airbrakes for landing, all of which I'm pleased to say were very uneventful yet very effective.
The craft will now fly in the gentlest of breezes (demonstrated by George) at a slow walking pace and at about 12 ft above the runway with no sign of stalling, whilst at the other end of performance curve, conducts barrel rolls and loops without effort. With flaps the takeoff distance is about 30 yards whilst landing is almost spotted.
In the air, when emulating the full size craft, it looks and flies good. The sound of the two engines gives the whole package a nice bonus.
George remarked "It flies like a trainer, I really like flying this"........ I think it got his juices flowing.
See below for more Photos



