E-Help Twin Testflight

[@ThomasGrillo]

Back in the 70s, as a kid, I envisioned something like this, but pilots were afraid of having props too close to the arms and hands. Kinda wish I'd ignored them, and patented it, now. Mind you, my vision of this called for gas engines. Thanks for sharing this. Very cool! :)

[@AcrodesignerLNSNI]

Put two RC model airplane gas engines there and it will be a cool airplane. For not getting into the prop disc there is a limiting line in the pilot harness. Of course not a healthy configuration.

[@ThomasGrillo]

@@AcrodesignerLNSNI Well, not long after, I learned about ducted fan props, so that would've been the best solution, right there. I like the idea of model airplane engines. However, these days batteries have become so good, we're edging ever closer to the point they will, one day, surpass the efficiency of a gas engine in some cases. :)

[@AcrodesignerLNSNI]

@@ThomasGrillo When batteries at high C rate is 2 kg per kWh it will be compete with gas in aviation. Today practical batteries are at 8 kg per kWh

[@ThomasGrillo]

@@AcrodesignerLNSNI Still a ways to go, then. Thanks.

[@ariffbasri]

Amazing job!

[@AcrodesignerLNSNI]

Thanx :-)

[@eco_guardian]

So amazing

[@edilbertosantana8307]

Nice PROJECT,, IF IS a hang glider pilot with care, and have have Good study of that ..atention So Will be no problem.Good work ..congratulation ..

[@Avianthro]

Electric propulsion for aircraft of this type does make sense, but only under one condition: They also need to be super quiet. Why have an electric motor that's natrually super quiet but with noisy props?? The direction to go is a high-pitch prop with a diameter as large as practical in the tail (a la Mosquito harness) turned by a motor that's as slow as possible. Electric motors are far easier to engineer for low RPM high torque in a light and compact design, without redux drives, than are combustion engines. The prop will have a very low disc loading for an aircraft of this weight and should be able to turn very slowly with a highly pitched blade...the strategy of the old Lockheed YO-3A. We can then have a super-quiet birdlike flying machine.

[@AcrodesignerLNSNI]

We had E-Help with big diameter 130 cm prop geared down to 2200 rpm. However, problem is practicallity. The big prop needs a long legged under carriage. And in flight impose a huge torque on the glider that makes handling a bit bad. So it seems like butter zone for all practical, good handling and still good performance 4 amps per kilo thryst at 52 volts is around 90 cm prop diameter. It is tip speed that makes noise. Below mach 0,5 pretty quiet but above 0,7 starts getting hard noise. At 0,8 pretty bad and at sub sonic terrible.

[@Avianthro]

@@AcrodesignerLNSNI Wow! Thanks for sharing that you've already done some experimentation in the direction of slower-turning props! Interesting...Hmmm...I guess if I were doing an electric propulsion system for a hang-glider, since my top priority would be making the unit a silent as possible, aiming for being as silent as a bird, I might then try to develop either a system with twin motors with counter-rotating props in pusher config mounted directly to the wing's TE or I'd try to design a contrarotating propset and mount it on the CL TE with a long enough shaft to make sure it doesn't endanger pilot's legs. (There are already contrarotating prop gear boxes for the little indoor RC pattern-flying planes.) It seems so sad to me that we have the silent motor but we can't get the prop silent, almost, too. The YO-3 was amazingly quiet even though it was not electric. Surely, if there's a will, there's a way to do even better with electric on a hang glider, right?

[@robincelius8376]

Cool set-up. Wonder how it would be to control the thrust on each engine with weight-shift in both roll and pitch.

[@AcrodesignerLNSNI]

Interesting thought. However, the risk of assymmetric thrust and a spin situation in case of one engine out would be harder to adress then. With two motors on one ESC it is easier. Manouvering is not an issue with this setup as the glider is pretty easy handling anyway.

[@tonymerrifield583]

What is the plan for a battery fire?

[@Okiem.dyslektyka]

what range without altitude change? more or less?

[@AcrodesignerLNSNI]

About 300 meter climb and/or 5 km range on 1 kWh

[@harryk247]

Raider, I want to suggest that you put the motors at the center of gravity cg. Then try it again in glide mode and thermal glide. By having the motors and batteries located at the cg, the nose heavy problem is solved. Anything you add at the cg point will not affect the aerodynamics of the glider, as far as the glider is concerned, it is in balance. Harry

[@AcrodesignerLNSNI]

Yes, it would probably fix the nose heavyness. However, it is still not a very efficient thermalling glider as there is too much drag and stuff hanging out in the breeze. So for thermalling it is way more efficient to go back to single engine and lighter small gliders. As Pink (Bautek Astir) and the various versions of E-Help

[@javierfloresclaudio4932]

Hi from México... How much that motors ??? Where can i to Buy It ??? Can i to instal on a Falcón 195 ???

[@AcrodesignerLNSNI]

It is Turnigy Rotormax 150 motors from Hobbyking that I have rewound stator from 150 KV to 105KV. Motors used to cost some 400 usd each

[@danilocarno]

... What a nice project, a question: How do I steer right and left on the floor when maneuvering? Maybe I understand: you want to turn left then from the most powerful to the right engine?!?!?! Nice job, a cordial greeting

[@AcrodesignerLNSNI]

DANILO GEROSA Standard Wills Wing swivel wheels for tandem glider. Steers on a handle on the right wheel

[@danilocarno]

... Thanks Reidar, next month I will buy a Wills Wing Sport 2-175. And because I'm 64 years old and less air in the lungs I see that your idea of 2 engines is very good. Did you try to turn off one of the two engines during the flight? It would be interesting to know the behavior of the wing in the event of this type of emergency. I think I can mount 2 DA-200 Desert Aircraft engines (19 HP each), very good for remote control airplanes and weighing 5 kg each. www.desertaircraft.com/products/da-200 So I think this grandfather can fly. Many thanks Reidar, good day and follow flying like that. DANILO

[@AcrodesignerLNSNI]

Hi. I never trird to cut off one engine and probably that would be pretty critical swing. Instead the two electrical motor stator windings are paralelled into same ESC to avoid excactly that. Then it is impossibel to run only one motor. The gas engines You mentioned I know from a RC tug project we are doing now and two of those sure have enough power. Will be pretty noisy for the pilot though and must be quick to cut off the running engine in case one quits.

[@danilocarno]

Thanks Reidar, all this makes me think that it's best to switch to an electrical configuration: 2 motors connected to a single ESC. What I see dangerous is that if you leave the control bar and due to the traction of the engines the wing is projected immediately to the brake position with respect to the flight direction, that is, it has the same effect as to push your arms forward to exercise the 'Brake action as in a landing, so you immediately get lost in livelihood. Thank Reidar, we are in touch a cordial greeting.

[@AcrodesignerLNSNI]

Thanks Danilo. Yes, letting go of the control bar at full throttle two engines turning at 20 kg thrust each would be pretty bad. Would probably climb very steeply and stall at some point. Thats why the motor cable pull cord thing. To stop the thing in case the pilot and glider are not at same place.

[@mopedinthemalverns6661]

Doesn't hte engine need to be on the pilot ie on the hang point not on the A frame?

[@AcrodesignerLNSNI]

As close to the center of mass as possible. And that is about right over the pilot back

[@nritonga3874]

how much power each motor of this plane?

[@AcrodesignerLNSNI]

About 5 kW each

[@nritonga3874]

@@AcrodesignerLNSNI what is the smallest power of each motor that can be used?

[@AcrodesignerLNSNI]

@@nritonga3874 Depend on the weight of the pilot and size of glider. I am 85 kg and tandem glider is at about 35 kg, wheels are very heavy for tandem aerotow maybe 10 kg so the power needed to get that thing airborn is maybe 2x6 kW. If pilot is light weight, glider small singel surface and wheels made small. Then maybe 2x4kW is plenty. Mind the propeller efficiency though. Some high rpm RC model airplane solutions tend to be optimized for high airspeed models and not our slow flying heavy hanggliders. We need lower rpm, higher torque and big diameter prop at tip speed max 250 m/s. Above that will just cost efficiency.

[@iamamazingist]

very nice ..

[@mehmedalierisir4845]

How many kw each motor??

[@Flyit37075]

It looks like you run both motors off a single turnigy delux 250 amp ESC ? Any special way to set up, or did you just pigtail and solder the motor wires after checking them for correct motor direction

[@AcrodesignerLNSNI]

No special setup at all. The Turnigy 250 delux ESC from hobbyking straight out of the box. It is a really good ESC and very well adapted to the Rotormax 150 motor even when rewound to 105 KV and two motors run in cascade - that is parallell motor cables. As long as both motors are pretty same electrical characteristics and same props it works very nicely. Hold back one of the props for assymetric load and then the ESC will be confused and start running erratic. Then just stop and restart and all good again.

[@NoTengoIlusiones]

Hi again, I know you're in testing and love the Lubin type Shuchanek open face helmet. But if the props are in front I beleive it's an important safety measure to wear full face with mask... at least you have some ' canopy ' protection. ( not for arms/ shoulders) but face is more sensitive. Cheers

[@AcrodesignerLNSNI]

NoTengoIlusiones On this one a limiting line that prevents face or arms to move forward into prop discs did the job. Also the motor plug is pulled out if moving forward. Regarding full face helmet I’m not a fan of it because for hanggliding You need a very good feel for airspeed and most full face helmets are bad for that. You simply fly better with better feel.

[@NoTengoIlusiones]

Reidar Berntsen Thanks for reply. I remember this since for towing ( Nordic static line system) we put a rule in the club to wear wheels for towing + Goggles + full face helmet in case of falling of cart, or unexpected slack in towing line hitting you. I've flown with many helmets and right now I've two: Icaro 4fight full face and Lubin carbon open face. I can tell you that the major difference(in use) is weight. Icaro is so well designed that you forget you have a full face !! ( I've flown many years with Charly Insider and it's completely different). For riding my bike I use open face for the reasons you've mentioned ' feel the traffic. Cheers

[@packindarkies2103]

Wow. How's the angle of attack during cruise?

[@AcrodesignerLNSNI]

About handsoff and normal during cruise. Motor off a bit nose heavy, and opposite at full takeoff power

[@Владимир.иванович.сибирякСторо]

👍👍👍👍👍😀

[@Flyit37075]

what would you estimate flight time to be with this set up ?

[@AcrodesignerLNSNI]

20 minutes

[@Flyit37075]

I have been following your work, your like a rock star to some of us. So excited to see your developments. I am in the process of setting up 4 , 90mm EDF in a harness . I bench tested them last weekend at 9 lb thrust static. Do you feel that 36 lb thrust is sufficient to flat land foot launch a Falcon 4 / 195 in light headwind ? , or will that be a struggle or a flop. Really appreciate your input. Jeff

[@AcrodesignerLNSNI]

+Jeff Reynolds 36 ibs on that big 190 footer will be about what it takes to cruise. Depending on Your body weight above or under 80 kg. Above 80 do not try a flatland start. Too much drag in that wing to overcome high aoa periode in start. Fly it off from a ramp rather. Fuel burn/ ampere draw is high with ducted fans. Looked at the numbers before and it is not so efficient as props, big diameter props that is

[@Flyit37075]

Thank Reidar, yep I'm 6, 3" 104kg, my goal is flat land foot launch so I will most likely set up the 150cc rotomax as per E help video 1. try to incorporate two EDF as additional booster for flatland foot launch. Cant find a mossy around these parts. Don't want to shell out retail for new mosquito NRG 6K $ USD. I have seriously thought about 2 100cc rotomax maybe 24" props, as twin pushers off harness, one counter rotating. Your thoughts ?

[@fernandodanielalvarez3195]

good video, very good quality, it would be better to have a video with a camera at the end of the hang glider looking forward and do not see the hang glider and not see the person, so it looks like a person will fly for those beautiful places

[@AcrodesignerLNSNI]

Fernando Daniel Alvarez Well, often the cam pos is more for tech study after to see how things worked or not worked. In this case to study the pitch trim impact this motor config had on the glider.

[@Mike-01234]

Lithium polymer batteries on your back what if they catch fire. I think rather just have an E powered ultralight.

[@Vedrozhil]

hang gliding in general is a dangerous thing 8)

[@godspeedlion]

Wow

[@CabrioDriving]

What if batteries explode and these are on your back? You can't do nothing then. It is a design problem hard to solve. You can't land on batteries bellow you, you have a risk when these are on your back as well. If the batteries would be bellow you, you have a chance to drop them like a bomb;) But then, how to land. what if you had these batteries inside arms of your glider? hmm

[@AcrodesignerLNSNI]

Cabrio Driving In The Alps The metal tray is designed and tested for blowing one 14s block without spreading to others. However, batteries are most at risk when charging, not decharging. Over 4 years we have blown a few batteries without drama. Did not even land because of it. Just continoued flight.

[@kevinjames5510]

Hello there, great work i was wondering why not build 18650 packs ( for your projects in general), if I'm not mistaking Panasonic ncr18650b has more energy density then regular lipos packs like those. Also LipoFe will basically never catch fire, are lighter and has more energy density then lipos. They are basically in the price range of what you guys are using now. What C rating do you need? AWESOME stuff by the way i don't even fly (just RC) but more affordable solutions like these can get more people into it for sure, whats your fly time with average thermals? (Including on the obviously more efficient e HELP models.) Again great work, thanks for sharing, I've watched a few videos of yours as we share some interests. - Kevin

[@AcrodesignerLNSNI]

18650 is way too low C rating. Need too many and heavy of them for not abusing C rate wise

[@freeflyer]

The more the better 😂

[@tmacarle]

OMG, that is a great idea. Let's put blades right out in front of our heads.

[@AcrodesignerLNSNI]

Thomas Macarle ...and top it up with a LithiumPolymer fireworks on Your back LOL !!

[@leiferiklangvand9888]

No, no, no! Hanggliding is ment to be without engine.

[@AcrodesignerLNSNI]

He he, I know. Thats why I do 99% of my flying without motor. However, as an engineer it is fun to play with powered flight clos to my home

[@kurdishallahuakbar4111]

WTF MANNE