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Posted

Hi,

I have a glider project, but I have no idea on how to do it. I need to do my own design.

The glider that I need should travel greater that 5 meters, and should travel in a straight line.

I tried to make one but its always make turns and travels with a shorter distance. I don't know what are the functions of each part of the glider, or what are the causes why its like that.

Can someone help me with this project??frown.gifsad.png

Posted

I think its too simple for a physics project???

I don't think it's too simple, no...

 

Turns: you should first make your plane more symmetrical, and this needs a clean work. Then, look at your plane, especially the tips of the wing's trailing edge. Try to curve then gently upwards and downwards unsymmetrically; observe how, as a result, the plane rolls then turns. Once you've understood the effect, you can act on these tips to achieve a straigt flight.

 

Observe that all parts of a paper aeroplane, not just the wing tips, have an influence.

 

Worse, paper foldings have a significant thickness which does influence all aerodynamic moments, so if you fold the paper to the wing's upper side instead of lower, you get a plane that behaves a completely different way - often unmanageable. Or for instance, if you close the fuselage's folding with glue, you get a different design with different flight properties - usually it flies badly.

 

Much more difficult is the pitch stability. By curving both tips of the wing's trailing edge upwards or downwards, you pull the plane's nose up or down, which defines the equilibrium speed - but the plane has to have an equilibrium, which is difficult for pitch.

 

In short, the yaw stability of a plane is like an arrow, the pitch is not. When a plane flies exaggeratedly downwards, it accelerates, and the higher speed must achieve a pitch moment that pulls the nose. This is achieved by putting the mass forward and, when aeroplanes have several wings, using a bigger angle of attack at the forward wing - be this one smaller or bigger than the aft wing. Then, stability also needs damping, and this is very far from obvious...

 

For having only one wing, most paper planes are difficult to stabilize in pitch, and tend to oscilate in the vertical plane, or even diverge without oscilation. One design much sounder in this respect is that one:

http://www.zurqui.com/crinfocus/paper/airplane.html

- the tail is sometimes omitted but must be present. It is one major advantage of this model.

- extra flourish at the tail's end is not needed - but may have advantages

- bending the wingtips is not needed. It can be done downwards as well; observe the slower flight then.

It may look less easy to fold, but I very strongly recommend to start (...and finish) with this model as you'll get something usable in a finite time - which isn't the case with a random model. Once you've understood flight mechanics, you can try your own model... I'd say: change as little as you're allowed to. Like: bend the tips downward and observe the difference, or glue the fuselage closed (little glue!) and try to let it fly properly.

 

If some day you have completely understood what makes a good paper plane (which I haven't after thousands of trials) just tell us... There is more physics in it that you can study in months.

Posted

I don't think it's too simple, no...

 

Turns: you should first make your plane more symmetrical, and this needs a clean work. Then, look at your plane, especially the tips of the wing's trailing edge. Try to curve then gently upwards and downwards unsymmetrically; observe how, as a result, the plane rolls then turns. Once you've understood the effect, you can act on these tips to achieve a straigt flight.

 

Observe that all parts of a paper aeroplane, not just the wing tips, have an influence.

 

Worse, paper foldings have a significant thickness which does influence all aerodynamic moments, so if you fold the paper to the wing's upper side instead of lower, you get a plane that behaves a completely different way - often unmanageable. Or for instance, if you close the fuselage's folding with glue, you get a different design with different flight properties - usually it flies badly.

 

Much more difficult is the pitch stability. By curving both tips of the wing's trailing edge upwards or downwards, you pull the plane's nose up or down, which defines the equilibrium speed - but the plane has to have an equilibrium, which is difficult for pitch.

 

In short, the yaw stability of a plane is like an arrow, the pitch is not. When a plane flies exaggeratedly downwards, it accelerates, and the higher speed must achieve a pitch moment that pulls the nose. This is achieved by putting the mass forward and, when aeroplanes have several wings, using a bigger angle of attack at the forward wing - be this one smaller or bigger than the aft wing. Then, stability also needs damping, and this is very far from obvious...

 

For having only one wing, most paper planes are difficult to stabilize in pitch, and tend to oscilate in the vertical plane, or even diverge without oscilation. One design much sounder in this respect is that one:

http://www.zurqui.com/crinfocus/paper/airplane.html

- the tail is sometimes omitted but must be present. It is one major advantage of this model.

- extra flourish at the tail's end is not needed - but may have advantages

- bending the wingtips is not needed. It can be done downwards as well; observe the slower flight then.

It may look less easy to fold, but I very strongly recommend to start (...and finish) with this model as you'll get something usable in a finite time - which isn't the case with a random model. Once you've understood flight mechanics, you can try your own model... I'd say: change as little as you're allowed to. Like: bend the tips downward and observe the difference, or glue the fuselage closed (little glue!) and try to let it fly properly.

 

If some day you have completely understood what makes a good paper plane (which I haven't after thousands of trials) just tell us... There is more physics in it that you can study in months.

Yes, you were right, I think simple things will make me understand big things.

I'm reading yesterday about how to make gliders. Its true that I need to know first all the physics behind it before I make one.

Thanks this really helps a lot!wink.png

 

This link may help. http://www.ge.com/thegeshow/flight/#ch2, or it may be too basic.

Thanks! I enjoyed this, and it help me understand.smile.png

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