highspeed
Well-Known Member
I've been tossing around several ideas and concepts for some time. While waiting for payday to roll around so I can order Raymer's book, I have stepped up my research. I'm using this thread to think out loud; comments, suggestions, and opinions are welcome.
My concept is a lightweight single-seat sportplane in the AR-5 to Midget Mustang size range cruising at at least 140 mph. Since the engine is usually the single heaviest (and most expensive) component, selecting the engine will be critical as the airplane will largely be designed around it. With a lightweight airframe at a gross weight of 700 pounds i think 65 horsepower is a realistic minimum. A maximum horsepower of 100 hp should give excellent performance even if the weight is near 1000 pounds. Several aircraft engines are available in that range. The small Continentals come to mind (A-65, C-85, O-200). One issue with these is cosmetic. They are wide engines, necessitating cheek bulges a'la the Midget Mustang and RV3/4. Then there's the Rotax offerings, which have proven reliability, but a high cost. Even though Mike Arnold flew the AR-5 on a 2-stroke, I'm not entirely comfortable with the thought of a 2-stroke, given the risk of sudden stoppage. I know some people are designing around things like Generac V-twins, but I'd really have to play around with some configurations to see if my goals could be met with those power levels.
For construction methods I'm heavily leaning to wood construction. I worked with wood growing up since my dad has been woodworking for longer than I've been alive. I am comfortable fabricating with wood. Aluminum would be my second choice, and composites a distant third. I've done some fiberglass work before and did not really enjoy it. Any comments are welcome. I'll continue to update with thoughts and design updates as I get there.
My concept is a lightweight single-seat sportplane in the AR-5 to Midget Mustang size range cruising at at least 140 mph. Since the engine is usually the single heaviest (and most expensive) component, selecting the engine will be critical as the airplane will largely be designed around it. With a lightweight airframe at a gross weight of 700 pounds i think 65 horsepower is a realistic minimum. A maximum horsepower of 100 hp should give excellent performance even if the weight is near 1000 pounds. Several aircraft engines are available in that range. The small Continentals come to mind (A-65, C-85, O-200). One issue with these is cosmetic. They are wide engines, necessitating cheek bulges a'la the Midget Mustang and RV3/4. Then there's the Rotax offerings, which have proven reliability, but a high cost. Even though Mike Arnold flew the AR-5 on a 2-stroke, I'm not entirely comfortable with the thought of a 2-stroke, given the risk of sudden stoppage. I know some people are designing around things like Generac V-twins, but I'd really have to play around with some configurations to see if my goals could be met with those power levels.
For construction methods I'm heavily leaning to wood construction. I worked with wood growing up since my dad has been woodworking for longer than I've been alive. I am comfortable fabricating with wood. Aluminum would be my second choice, and composites a distant third. I've done some fiberglass work before and did not really enjoy it. Any comments are welcome. I'll continue to update with thoughts and design updates as I get there.
