Archive for March, 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

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%)

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.

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.