Sunday, March 30, 2008

Full span flaps effect on NASA LS417-karoliinamod

I changed the LS(1)-417 so that the trailing edge gap is zero (=sharpest achievable) instead of the large gap present in that airfoil (Janne's Mini-Sytky does not have this gap while Panu's Mini-Sytky has). According to simulation with Javafoil, this decreases the drag quite significantly. The airfoil has good Clmax at the same time with the low drag (approaches almost NLF414F).

I calculated that Clmax of 2.88 is possible with this profile with full span flaps with fowler inboard section. 

Quick calculation with aerocalc shows that the following might be theoretically achievable:

AR 9
Clmax 2.88
Wing area 4.6 m2
span 6.4 m
Wing loading 144 kg/m2 29 lbs/sqft
L/D max 22
Stall speed 55 kts
Max level speed 260 kts 480 km/h with Rotax 914 (90 hp required out of 115, max continuous 100 hp->ok)
best glide speed 150 kts
empty weight 366 kg
mtow 666 kg


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