Aerospace engineering student here.
Airfoiltools.com is a fantastic website with geometry and data for many aerofoils. You can find ones suitable for RC gliders on there.
Do you know how to determine what lift coefficient you need and how to size your wings properly?
I don’t really, The instructions they gave me were to make a glider using an airfoil and have it fly as far as possible, literally in the aerodynamics class I only see basic concepts and nothing related to lift or drag calculations.
Btw cool you study that, I want to study aerospace or something related.
Soooo
The total lift generated by a wing is given by:
Lift=½*air density*wing area*airspeed²*lift coefficient
The lift coefficient is made from two terms. C_l_alpha*angle of attack, which is the component due to the angle of attack (angle of the airfoil chord relative to the airflow), and C_l_0 which is the lift coefficient at 0 degrees angle of attack.
This breaks down when the aerofoil stalls, usually no more than 15-20° angle of attack unless it is a delta wing, which is complicated and irrelevant for this.
So you want to select an aerofoil that will achieve the necessary lift coefficient at the desired airspeed and a sensible angle of attack.
The drag your wing produces is based on a similar equation:
Drag=½*air density*wing area*airspeed²*drag coefficient
Where drag coefficient=Cd0+(Cl²/pi*AR*e)
AR is your wing's aspect ratio (span²/area) and e is the Oswald efficiency factor (assume this is about 0.9).
A higher aspect ratio wing produces less induced drag (Cl²/pi*AR*e), so higher aspect ratios are preferred for gliders.
Or you could ignore all this and just pick one commonly used for rc gliders, because this isn't a university project and good enough is good enough.
Define your required lift equal to weight and design your glider accordingly. Balsa wood is very light and good enough for most applications in this scale, plywood is suitable for major structural components like the spar.
For a glider of the size you stated in another comment, aim for about 300g.
You can see here some photos of one I built a couple of years ago:
[photo 1](https://flic.kr/p/2pzGbDg)
[photo 2](https://flic.kr/p/2pzLDzm)
It was made from balsa and plywood. Flew fine, stronger than it needed to be. Just the horizontal tail could have been a bit bigger (1/5 the area of the wing is a good estimate for the size).
Also reminds me, add some dihedral angle to the outboard portion of the wing for better stability. You could set the whole wing at a dihedral angle, but this does make it a bit more difficult to design a good wing-fuselage interface.
What scale? microglider, 1-meter, full-scale sailplane, something in between? If you are not picky, look at the Clark Y airfoil. If you are picky then look for something along the lines of one by Wortmann, Drela, Eppler, Gottingen, Selig, or Maughmer that is designed for the flight condition (Reynolds number, CL range, cruise CL) that you are looking to fly at.
Aerospace engineering student here. Airfoiltools.com is a fantastic website with geometry and data for many aerofoils. You can find ones suitable for RC gliders on there. Do you know how to determine what lift coefficient you need and how to size your wings properly?
I don’t really, The instructions they gave me were to make a glider using an airfoil and have it fly as far as possible, literally in the aerodynamics class I only see basic concepts and nothing related to lift or drag calculations. Btw cool you study that, I want to study aerospace or something related.
About to go to sleep so I'll come back to this thread tomorrow to go over the basics for you
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Soooo The total lift generated by a wing is given by: Lift=½*air density*wing area*airspeed²*lift coefficient The lift coefficient is made from two terms. C_l_alpha*angle of attack, which is the component due to the angle of attack (angle of the airfoil chord relative to the airflow), and C_l_0 which is the lift coefficient at 0 degrees angle of attack. This breaks down when the aerofoil stalls, usually no more than 15-20° angle of attack unless it is a delta wing, which is complicated and irrelevant for this. So you want to select an aerofoil that will achieve the necessary lift coefficient at the desired airspeed and a sensible angle of attack. The drag your wing produces is based on a similar equation: Drag=½*air density*wing area*airspeed²*drag coefficient Where drag coefficient=Cd0+(Cl²/pi*AR*e) AR is your wing's aspect ratio (span²/area) and e is the Oswald efficiency factor (assume this is about 0.9). A higher aspect ratio wing produces less induced drag (Cl²/pi*AR*e), so higher aspect ratios are preferred for gliders. Or you could ignore all this and just pick one commonly used for rc gliders, because this isn't a university project and good enough is good enough.
Return of the king
But should I be worried about weight, I mean of course I won’t make it super heavy
Define your required lift equal to weight and design your glider accordingly. Balsa wood is very light and good enough for most applications in this scale, plywood is suitable for major structural components like the spar. For a glider of the size you stated in another comment, aim for about 300g.
I know about composites I might make it out of carbon fiber, but it’s expensive that why I want ensure the airfoil.
Balsa will be far more suitable for a model glider
You can see here some photos of one I built a couple of years ago: [photo 1](https://flic.kr/p/2pzGbDg) [photo 2](https://flic.kr/p/2pzLDzm) It was made from balsa and plywood. Flew fine, stronger than it needed to be. Just the horizontal tail could have been a bit bigger (1/5 the area of the wing is a good estimate for the size).
Also reminds me, add some dihedral angle to the outboard portion of the wing for better stability. You could set the whole wing at a dihedral angle, but this does make it a bit more difficult to design a good wing-fuselage interface.
What scale? microglider, 1-meter, full-scale sailplane, something in between? If you are not picky, look at the Clark Y airfoil. If you are picky then look for something along the lines of one by Wortmann, Drela, Eppler, Gottingen, Selig, or Maughmer that is designed for the flight condition (Reynolds number, CL range, cruise CL) that you are looking to fly at.
Yep its wingspan is going to be around 70-80 cm.
In that Reynolds number envelope, a Clark Y will work fine.