Originally Posted by Confabulous
Speaking of x-plane and microlights, I wondered what the maximum level flight speed of a 450kg VLA would be, so I designed a rough model. It has an 80hp engine (neglecting cooling drag for the moment, also with retractable gear and a NACA23-016 shaped fuselage (carbonfibre, 0.012 Cd without any antennae, pure aerofoil shape)) the wings are NACA23016 (root) and NACA0009 (tip) with 1 degree of washout. Horizontal tail surfaces don't exist, the elevator is part of the aerofoil-shape fuselage. It's taildragger until I can figure out how to curb the psuedo-groundloop behaviour of the nosedragger!
Some interesting results...
(All results are at MAUW)
212KTAS at METO (1800ft, ISA standard)
184KTAS at 75% (1800ft, ISA standard)
1700fpm ROC @ 86KIAS
Stall is elevator limited at around 55kts (power off, flaps up)
Stalls at 28kts (power on, flaps down)
Just an excercise, but an interesting one!
(And yes, I know the Cd is very low, should be around 0.017, but it's only a rough model)
Whilst a typical real-world microlight of that sort of size and shape will probably give you something like:
- 75-100kn CAS maximum level cruise
- Climb ~800-1100 fpm at sea-level
- Stall at ~33 knots power off, flaps down
- Stall at ~30 knots power on, flaps down
- Stall may be elevator limited clean, but is likely to be around 38 knots.
G