Archive for the ‘ flap ’ Category

>Slotted flap design

>Slotted flap slot design

AERADE Reports Archive, search keyword slotted

http://aerade.cranfield.ac.uk/ara/dl.php?filename=1947/naca-tn-1395.pdf

http://aerade.cranfield.ac.uk/ara/dl.php?filename=1947/naca-tn-1463.pdf

http://aerade.cranfield.ac.uk/ara/dl.php?filename=1950/naca-tn-2149.pdf

http://aerade.cranfield.ac.uk/ara/dl.php?filename=1949/naca-report-942.pdf

Slotted flap design

Slotted flap slot design

AERADE Reports Archive, search keyword slotted

http://aerade.cranfield.ac.uk/ara/dl.php?filename=1947/naca-tn-1395.pdf

http://aerade.cranfield.ac.uk/ara/dl.php?filename=1947/naca-tn-1463.pdf

http://aerade.cranfield.ac.uk/ara/dl.php?filename=1950/naca-tn-2149.pdf

http://aerade.cranfield.ac.uk/ara/dl.php?filename=1949/naca-report-942.pdf

Idea: fowler slotted flapelevators, how to improve the efficiency of a tandem wing aircraft

I have been thinking how the efficiency of a tandem wing aircraft could be improved. In tandem wing aircraft the front wing determines pretty much how high total Clmax the aircraft is going to have which translates then to the required wing area. To maximize the efficiency, because flaps can not be used in the rear wing, the Clmax of the front wing is desirable to be as high as possible. Usually on tandem wing and canard aircraft the Clmax of the front wing is around 2.0 and the elevator is a single slotted flap.

It may not be mechanically very practical, but theoretically it could be possible to increase the Clmax of the front wing by adding more high lift devices into it. There could be a fowler flap implemented so that it increases the wing area substantially while the single slotted elevator flap remains working as usual in the trailing edge. The problem is that how you do that when the whole elevator system moves as consequence when the flaps are lowered or raised (the fowler is either inside the wing or protruded out of the trailing edge). But if this was practical with any other means than using servo motors for the elevator too, it could increase the available lift from the front wing somewhat. A challenging thing in this obviously is that the shear web that connects the spar caps goes through the front wing, and the flap system can not break the integrity of the shear web. More limiting factor also is that the chord length of a tandem wing aircraft front wing is low and there is not that much space for the high lift device.

Anyway, it would be interesting to try this out with a radio controlled model.

I hereby license this invention under the terms and conditions of GNU General Public License, version 3, or any later version. (C) 2008 Karoliina Salminen. All rights reserved. By reading this text, you aknowledge this and agree with the terms and conditions of the GPL license.

>Idea: fowler slotted flapelevators, how to improve the efficiency of a tandem wing aircraft

>I have been thinking how the efficiency of a tandem wing aircraft could be improved. In tandem wing aircraft the front wing determines pretty much how high total Clmax the aircraft is going to have which translates then to the required wing area. To maximize the efficiency, because flaps can not be used in the rear wing, the Clmax of the front wing is desirable to be as high as possible. Usually on tandem wing and canard aircraft the Clmax of the front wing is around 2.0 and the elevator is a single slotted flap.

It may not be mechanically very practical, but theoretically it could be possible to increase the Clmax of the front wing by adding more high lift devices into it. There could be a fowler flap implemented so that it increases the wing area substantially while the single slotted elevator flap remains working as usual in the trailing edge. The problem is that how you do that when the whole elevator system moves as consequence when the flaps are lowered or raised (the fowler is either inside the wing or protruded out of the trailing edge). But if this was practical with any other means than using servo motors for the elevator too, it could increase the available lift from the front wing somewhat. A challenging thing in this obviously is that the shear web that connects the spar caps goes through the front wing, and the flap system can not break the integrity of the shear web. More limiting factor also is that the chord length of a tandem wing aircraft front wing is low and there is not that much space for the high lift device.

Anyway, it would be interesting to try this out with a radio controlled model.

I hereby license this invention under the terms and conditions of GNU General Public License, version 3, or any later version. (C) 2008 Karoliina Salminen. All rights reserved. By reading this text, you aknowledge this and agree with the terms and conditions of the GPL license.

Idea: fowler slotted flapelevators, how to improve the efficiency of a tandem wing aircraft

I have been thinking how the efficiency of a tandem wing aircraft could be improved. In tandem wing aircraft the front wing determines pretty much how high total Clmax the aircraft is going to have which translates then to the required wing area. To maximize the efficiency, because flaps can not be used in the rear wing, the Clmax of the front wing is desirable to be as high as possible. Usually on tandem wing and canard aircraft the Clmax of the front wing is around 2.0 and the elevator is a single slotted flap.

It may not be mechanically very practical, but theoretically it could be possible to increase the Clmax of the front wing by adding more high lift devices into it. There could be a fowler flap implemented so that it increases the wing area substantially while the single slotted elevator flap remains working as usual in the trailing edge. The problem is that how you do that when the whole elevator system moves as consequence when the flaps are lowered or raised (the fowler is either inside the wing or protruded out of the trailing edge). But if this was practical with any other means than using servo motors for the elevator too, it could increase the available lift from the front wing somewhat. A challenging thing in this obviously is that the shear web that connects the spar caps goes through the front wing, and the flap system can not break the integrity of the shear web. More limiting factor also is that the chord length of a tandem wing aircraft front wing is low and there is not that much space for the high lift device.

Anyway, it would be interesting to try this out with a radio controlled model.

>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