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

Idea: Full span flaps

Full span flaps with flapped ailerons:

In board wing has 60% span fowler flaps. Outboard wing, the remaining 40% consists plain flap type flaperons with similar mechanism than used in Mini-Sytky.

deltaClmax_fowler = 0.6 * 1.67 + 0.4 * 0.9 = 1.362

For airfoil with Clmax 1.2 the maximum Clmax on landing configuration is thus 1.32 + 1.362 = 2.68

This allows smaller wing area and higher wing loading to be used without sacrificing takeoff and landing performance too much.

Another variation with single slotted flaps:

deltaClmax_singleslotted = 0.6*1.18 + 0.4*0.9 = 1.06

+1.06 in Clmax still is a very good value and better that would be obtained with full span flaperon (+0.9). For airfoil with Clmax of 1.32 this yields Clmax of 2.37.

This idea has not been tested in practice and is not guaranteed to work.

Effects on aircraft:

Aircraft with 60% span plain flap and Wortman FX 38-153 (no full span high lift device):

Clmax = 1.3 + 0.9*0.6 

deltaClmax = 0.54

Clmax => 1.84

86 hp required for 200 kts cruise

wing loading: 92 kg / m2

wing area: 7.2 m2

stall speed: 55 kts

design cruise: 200 kts

Cdtot = 0.011 (with boundary layer suction)

Same aircraft with full span flaperon and Wortman FX 38-153:

Clmax = 1.3+0.9 =  2.20

Same aircraft parameters:

76 hp required for 200 kts cruise

wing loading: 110 kg / m2

wing area: 6 m2 

Aircraft with full span flaps with slotted inboard section:

Clmax = 1.3 + 1.06 = 2.36 

Same aircraft parameters:

74 hp required for 200 kts cruise

wing loading: 118 kg / m2

wing area: 5.6 m2

Aircraft with full span flaps with fowler inboard section:

Clmax = 1.3 + 1.362 = 2.66

70 hp required for 200 kts cruise

wing area: 5 m2

wing loading: 134 kg / m2

For the most extreme case theoretical savings over usual configuration:

Power = 86-70 = 16 hp (18%)

wing loading: 134-92 = 42 kg/m2 (31%)

wing area: 7.2 m2 - 5 m2 = 2.2 m2 (30%)

Karoliina model 1 iteration 1

Karoliina model 1 concept iteration 1

200 kts with Rotax 914

Specs:
2 places: side by by side staggered seating (co-pilot a bit behind pilot)
Configuration: Pusher with Y-tail.
Engine: Rotax 914 115 hp (100 hp continuous), Propeller: Woodcomp SR3000
Body: 60% laminar flow body.
Body laminarity target: 100% laminar flow with suction.
Landing gear: Trigear, retractable nosegear, Steve Wright noselift. Main gear connected to wing spars at 90 degrees angle.
Wing configuration: Conventional, midwing position
Wing loading: 82 kg/m^2 (16.8 lbs/sqft)
Airfoil: NASA NLF(1)414F.
Flap config: Single slotted flaps with external hinges
AR = 10
L/Dmax = 19.8 at 115 kts
L (wing chord) = 0.8 m
wing area = 8 m^2
wing span = 8 m
Re min (stall) = 1829224
Re cruise = 4217074
Re max cruise = 5586254
empty weight = 366 kg
gross weight = 666 kg
fuel capacity = 140 liters
max cruise speed = 200 kts 370 km/h at 7000 feet
stall speed = 50 kts 92 km/h
approach speed = ~70 kts 130 km/h
drag coefficient target = < 0.016 (total drag). Lower is better. With 100% laminar flow body, a much lower drag coefficient might be possible, this figure is conservative.