Dave K
Member
Here are my initial ideas for an amphibious electric self-launch hang glider/ultralight:
Use an ultralight trike wing or hang glider wing with strut bracing, and mount an electric motor and folding pusher prop to each strut. The concept would be similar to this: Wasp Wing twin engine ultralight hang glider, Keith Sharon's twin engine Wasp Wing. - YouTube
The battery pack and controllers would hang from the strap with the pilot, and add to the shifted weight. Wires would run up the strap, with connectors near the hang point to wires that run down the downtubes and up the struts under the fairing to the motors.
The primary reason for mounting the motors there rather than using a typical powered harness with the prop at your feet is to allow for water takeoffs and landings on floats. Hopefully two motors would provide enough power for this. The reason for an amphibious powered hang glider instead of a regular unpowered one is that I live by a lake and there are other lakes and rivers nearby, and I don't want to have to drive long distances and rely on aerotows or other methods of getting in the air, and also to have the ability to hop around between lakes and other suitable landing areas.
I realize that the struts weren't designed with adding propulsion in mind, but the motor and prop combinations would be very light and would not produce a lot of thrust (maybe 60-90 lbs each). If necessary stronger tubes may be needed and the points where they attach may need to be reinforced.
The point on the strut where the motors attach and the angle the props are directed would be chosen to get the desired thrust line. Ideally the glider trim would be affected by added thrust such that it tended to pitch up somewhat proportional to thrust but still increase in airspeed as power is added. The idea is that there would be a moderate thrust level at which it flies level hands off, and past that it would climb. This is so the pilot would not have to fight the thrust with force on the bar, and to avoid either stalling or diving under power without pilot input. I'm not 100% sure this is possible, however. Since the thrust line would be below where the weight of the pilot hangs and pivots from, it would seem that any thrust would make it want to pivot up significantly, but I doubt it's that simple when aerodynamic forces come into play, and the overall CG is down lower because of the pilot weight and location. If the engines are far enough up the struts there should be a point at which it would behave as I described, and hopefully that isn't so far up (or so low) that it precludes decent sized props. The motors would mount to the struts using a mount that clamps onto them somehow and could be adjusted to find the right point. The motors would be counter rotating to cancel the torque.
Possibilities for launching and landing would be foot launch, wheels, or floats, with different bolt-on "gear" options. Foot launching and landing would be tough with the added weight of the batteries on the pilot's back, and the somewhat heavier wing plus motors, etc. A strong enough experienced hang glider pilot may be able to do it, but the intention would be to mainly use wheels or floats. Wheels robust enough for repeated takeoffs and landings would be needed, like that used on tandem trainers. I'd also like to have floats that could be used with optional wheels that could be folded up/down manually in the air for amphibious operations. There would be a float and retractable wheel mounted to each side where the base tube and down tubes meet, and a float at the back of the keel with a tiny wheel or replaceable skid/fin. Even skis could be fitted for snow/ice.
The most potentially suitable wing that I have identified so far is the North Wing Solairus 16M. It's a topless wing with struts, and it has a weight range of 320-420 lbs gross. That should be about right considering the weight of the wing itself, plus my weight, the harness, motors, props, controllers, and allow for 50-100 lbs of batteries, maybe more. The size of the battery pack used could vary based on the flight plan - from just enough to climb up into a thermal or ridge lift, to enough for an hour or more of sustained powered flight.
Potential motors I have identified are the Turnigy RotoMax 150cc (cheap and has about 13 hp each), The Plettenberg Predator 37, Joby JM1, or Scorpion HK-7050-340KV. This video (E-Help start from flatland - YouTube) shows a single Turnigy Rotomax with direct drive launching a hang glider from level ground. For simplicity direct drive is nice, but the small lightweight motors I'm looking at would be a lot more efficient and generate more thrust with a belt reduction and larger props. The same guy demonstrates this here (E-Help, R&D compare direct driven and geared Mossie version - YouTube). It's a matter of what works in the necessary mounting location without coming too close to striking the wing, ground, or pilot, or being too heavy. For simplicity and aerodynamics I am not planning to use shrouds.
I have ideas for constructing and mounting the floats and other things that I can get into once I have some comfort that this is possible and worth pursuing.
It seems from the first video that this should be possible (from land anyway), but I'm not sure about how practical it is. Please let me know your thoughts on how well this could work and what the potential drawbacks are. Ideas for different motor mounting configurations, different wings, motors, props, controllers, batteries, floats, etc. are all welcome.
I should note that my only flying experience so far is an introductory tandem hang glider ride, and an introductory lesson on a sand dune (and a few minutes at the controls of friends' small planes once airborne). I plan on taking hang gliding instructions before attempting to fly this myself. I have been thinking about and investigating powered hang gliders and ultralights for years (as well as other aircraft), and I'm finally at a point where I'm getting ready to buy/build something and take lessons.
Thanks,
- Dave
Use an ultralight trike wing or hang glider wing with strut bracing, and mount an electric motor and folding pusher prop to each strut. The concept would be similar to this: Wasp Wing twin engine ultralight hang glider, Keith Sharon's twin engine Wasp Wing. - YouTube
The battery pack and controllers would hang from the strap with the pilot, and add to the shifted weight. Wires would run up the strap, with connectors near the hang point to wires that run down the downtubes and up the struts under the fairing to the motors.
The primary reason for mounting the motors there rather than using a typical powered harness with the prop at your feet is to allow for water takeoffs and landings on floats. Hopefully two motors would provide enough power for this. The reason for an amphibious powered hang glider instead of a regular unpowered one is that I live by a lake and there are other lakes and rivers nearby, and I don't want to have to drive long distances and rely on aerotows or other methods of getting in the air, and also to have the ability to hop around between lakes and other suitable landing areas.
I realize that the struts weren't designed with adding propulsion in mind, but the motor and prop combinations would be very light and would not produce a lot of thrust (maybe 60-90 lbs each). If necessary stronger tubes may be needed and the points where they attach may need to be reinforced.
The point on the strut where the motors attach and the angle the props are directed would be chosen to get the desired thrust line. Ideally the glider trim would be affected by added thrust such that it tended to pitch up somewhat proportional to thrust but still increase in airspeed as power is added. The idea is that there would be a moderate thrust level at which it flies level hands off, and past that it would climb. This is so the pilot would not have to fight the thrust with force on the bar, and to avoid either stalling or diving under power without pilot input. I'm not 100% sure this is possible, however. Since the thrust line would be below where the weight of the pilot hangs and pivots from, it would seem that any thrust would make it want to pivot up significantly, but I doubt it's that simple when aerodynamic forces come into play, and the overall CG is down lower because of the pilot weight and location. If the engines are far enough up the struts there should be a point at which it would behave as I described, and hopefully that isn't so far up (or so low) that it precludes decent sized props. The motors would mount to the struts using a mount that clamps onto them somehow and could be adjusted to find the right point. The motors would be counter rotating to cancel the torque.
Possibilities for launching and landing would be foot launch, wheels, or floats, with different bolt-on "gear" options. Foot launching and landing would be tough with the added weight of the batteries on the pilot's back, and the somewhat heavier wing plus motors, etc. A strong enough experienced hang glider pilot may be able to do it, but the intention would be to mainly use wheels or floats. Wheels robust enough for repeated takeoffs and landings would be needed, like that used on tandem trainers. I'd also like to have floats that could be used with optional wheels that could be folded up/down manually in the air for amphibious operations. There would be a float and retractable wheel mounted to each side where the base tube and down tubes meet, and a float at the back of the keel with a tiny wheel or replaceable skid/fin. Even skis could be fitted for snow/ice.
The most potentially suitable wing that I have identified so far is the North Wing Solairus 16M. It's a topless wing with struts, and it has a weight range of 320-420 lbs gross. That should be about right considering the weight of the wing itself, plus my weight, the harness, motors, props, controllers, and allow for 50-100 lbs of batteries, maybe more. The size of the battery pack used could vary based on the flight plan - from just enough to climb up into a thermal or ridge lift, to enough for an hour or more of sustained powered flight.
Potential motors I have identified are the Turnigy RotoMax 150cc (cheap and has about 13 hp each), The Plettenberg Predator 37, Joby JM1, or Scorpion HK-7050-340KV. This video (E-Help start from flatland - YouTube) shows a single Turnigy Rotomax with direct drive launching a hang glider from level ground. For simplicity direct drive is nice, but the small lightweight motors I'm looking at would be a lot more efficient and generate more thrust with a belt reduction and larger props. The same guy demonstrates this here (E-Help, R&D compare direct driven and geared Mossie version - YouTube). It's a matter of what works in the necessary mounting location without coming too close to striking the wing, ground, or pilot, or being too heavy. For simplicity and aerodynamics I am not planning to use shrouds.
I have ideas for constructing and mounting the floats and other things that I can get into once I have some comfort that this is possible and worth pursuing.
It seems from the first video that this should be possible (from land anyway), but I'm not sure about how practical it is. Please let me know your thoughts on how well this could work and what the potential drawbacks are. Ideas for different motor mounting configurations, different wings, motors, props, controllers, batteries, floats, etc. are all welcome.
I should note that my only flying experience so far is an introductory tandem hang glider ride, and an introductory lesson on a sand dune (and a few minutes at the controls of friends' small planes once airborne). I plan on taking hang gliding instructions before attempting to fly this myself. I have been thinking about and investigating powered hang gliders and ultralights for years (as well as other aircraft), and I'm finally at a point where I'm getting ready to buy/build something and take lessons.
Thanks,
- Dave
