Solar hang glider
Im trying to figure out a lightweight rigid-wing foot launched hang glider. It will have PV cells to charge a battery for 1 hour and fly powered for 5 minutes,
then glide down (or soar). It is not possible to sustain flight only on PV cells, because their power (3kW max ideal, in practice 2 or less) is not enough for this purpose.
The materials used will be aluminum tubing (spars), plywood and foam (ribs), aluminum sheet (leading edge) and ??? something transparent for covering the wings (have not
looked at it yet, but dont mind that for now)
The building should be straightforward and simple, because I am not sure I can build anything but a simple wing.
IMPORTANT NOTE = The #1 priority is not to glide well. It is to be built easily, be lightweight and strong.
Now there are three configurations that I can think of: monoplane, biplane, and swept biplane.
1.
= Monoplane: This will likely produce the less drag, which is important. But I dont know how to build such a strong wing. The next options are easier because they are biplanes (I am counting or wire bracing). Also, the rudder thing is kind of complex (like the ATOS) and I am not sure I can build something like that.
(I can not build it swept or variable aspect ratio or dihedral so it has to be flat like in the picture).
2.
= Biplane: this is my favorite because I think I could pull this off. Wings are flat (no dihedral), aspect ratio does not change, and there is no stagger (so that the wire bracing is easy and effective). Pitch control is by weight shift, yaw/roll control is with pull-wire rudders. The problem with this is that it will be draggy, but that's Ok I can live with it.
It will also have more wing area than [1] and hopefully will not be much heavier (because of the bracing wires used, thats WW1 stuff).
3.
= Swept biplane: this is better than the previous one, but its harder to build because the wings are swept. I dont think I can do it.
The question is: will number [2] above fly well ? "Well" means be controllable and have no dangerous qualities. I am worried about tip-stalls since the aspect ratio is constant. What happens if such a design tip-stalls ?
All tails are optional and they can not have moving fins (I can not build something that complex). Their size could be made larger or have a vertical stabilizer instead of a V-tail. I just threw them in to show that a tail is possible. But dont take them very seriously.
Thank you for your patience!
PS 1: Those are the specifications:
1. 15 - 20 m2 wing area for plenty of Photovoltaic cells
2. Foot launched and landed.
3. 2.5 - 3.0 kW of PV cell power (ideal max) and 5-7 kW of motor power. Battery 0.5 - 1.0 kWh.
4. It is acceptable to require some downhill to take off from.
5. Fully powered by the motors it should gain altitude easily.
Casual usage will be: take it to the beach, let it charge for 1 hour or less, take off from some hill, power it up to gain altitude for 5 minutes,
then switch to charging the battery and glide/soar. Upon landing you could charge it again and fly again. If charging time is about 1 hour
and flight time is 5 min powered + another 5 min to get down = 10 min, then we have a 1:6 ratio which is not bad I guess. Charging the battery
while soaring will even improve this ratio (for example if you soar for 30 minutes while charging, you could even power it up again for a little while,
or reach the ground with only 30 minutes more left for charging).
PS 2: This is a lifelong dream, I am now 42 and decided to get started about it because it is a recurring dream that I know will never go away.
It might take me a decade or more to build; or then again, it might never be finished. But that's Ok, the point is to work with it and see what happens.
Because as I said, the "disease" will never go away
Im trying to figure out a lightweight rigid-wing foot launched hang glider. It will have PV cells to charge a battery for 1 hour and fly powered for 5 minutes,
then glide down (or soar). It is not possible to sustain flight only on PV cells, because their power (3kW max ideal, in practice 2 or less) is not enough for this purpose.
The materials used will be aluminum tubing (spars), plywood and foam (ribs), aluminum sheet (leading edge) and ??? something transparent for covering the wings (have not
looked at it yet, but dont mind that for now)
The building should be straightforward and simple, because I am not sure I can build anything but a simple wing.
IMPORTANT NOTE = The #1 priority is not to glide well. It is to be built easily, be lightweight and strong.
Now there are three configurations that I can think of: monoplane, biplane, and swept biplane.
1.
= Monoplane: This will likely produce the less drag, which is important. But I dont know how to build such a strong wing. The next options are easier because they are biplanes (I am counting or wire bracing). Also, the rudder thing is kind of complex (like the ATOS) and I am not sure I can build something like that. (I can not build it swept or variable aspect ratio or dihedral so it has to be flat like in the picture).
2.
= Biplane: this is my favorite because I think I could pull this off. Wings are flat (no dihedral), aspect ratio does not change, and there is no stagger (so that the wire bracing is easy and effective). Pitch control is by weight shift, yaw/roll control is with pull-wire rudders. The problem with this is that it will be draggy, but that's Ok I can live with it. It will also have more wing area than [1] and hopefully will not be much heavier (because of the bracing wires used, thats WW1 stuff).
3.
= Swept biplane: this is better than the previous one, but its harder to build because the wings are swept. I dont think I can do it. The question is: will number [2] above fly well ? "Well" means be controllable and have no dangerous qualities. I am worried about tip-stalls since the aspect ratio is constant. What happens if such a design tip-stalls ?
All tails are optional and they can not have moving fins (I can not build something that complex). Their size could be made larger or have a vertical stabilizer instead of a V-tail. I just threw them in to show that a tail is possible. But dont take them very seriously.
Thank you for your patience!
PS 1: Those are the specifications:
1. 15 - 20 m2 wing area for plenty of Photovoltaic cells
2. Foot launched and landed.
3. 2.5 - 3.0 kW of PV cell power (ideal max) and 5-7 kW of motor power. Battery 0.5 - 1.0 kWh.
4. It is acceptable to require some downhill to take off from.
5. Fully powered by the motors it should gain altitude easily.
Casual usage will be: take it to the beach, let it charge for 1 hour or less, take off from some hill, power it up to gain altitude for 5 minutes,
then switch to charging the battery and glide/soar. Upon landing you could charge it again and fly again. If charging time is about 1 hour
and flight time is 5 min powered + another 5 min to get down = 10 min, then we have a 1:6 ratio which is not bad I guess. Charging the battery
while soaring will even improve this ratio (for example if you soar for 30 minutes while charging, you could even power it up again for a little while,
or reach the ground with only 30 minutes more left for charging).
PS 2: This is a lifelong dream, I am now 42 and decided to get started about it because it is a recurring dream that I know will never go away.
It might take me a decade or more to build; or then again, it might never be finished. But that's Ok, the point is to work with it and see what happens.
Because as I said, the "disease" will never go away
