DIY ultralight, Retro biplane style, twinprop

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spinningmagnets
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DIY ultralight, Retro biplane style, twinprop

Post by spinningmagnets » Thu Oct 26, 2017 10:38 pm


melodious
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Re: DIY ultralight, Retro biplane style, twinprop

Post by melodious » Fri Oct 27, 2017 12:37 am

The propellors to airplane ratio behaves curiously like hubmotor to wheel diameter ratio. At first, I doubted the propellers weren't sized appropriately until he gunned the throttle to 75%. :lol:

If for some reason, she won't fly, it should be a simple swap out of one or more of the battery, controller, motor, propellor variables. :wink:

But why wood vs. a lightweight metal :?: Will it withstand the test of time? Or maybe, it's a prototype proof of concept build? :idea:
Surly Ogre rigid 29er, rear 10T MAC @ 50V 25AH & 40A: 30mph road/gravel/hill machine
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Next: eMTB @10-12s & 8"-12" pneumatic wheels; Got Strapped? d-(',')z

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Re: DIY ultralight, Retro biplane style, twinprop

Post by helno » Fri Oct 27, 2017 7:34 pm

He doesn't have enough power with those engines stock wind.

The same ones were used a while back on a Lazair ultralight and they were marginal even after being rewound for more power. The Lazair is a really light aircraft with a huge wing area so it has very low power requirements.

It is an interesting read.

https://www.rcgroups.com/forums/showthr ... ric-Lazair

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Re: DIY ultralight, Retro biplane style, twinprop

Post by PizzaWizard » Tue Oct 31, 2017 3:50 am

helno wrote:He doesn't have enough power with those engines stock wind.

The same ones were used a while back on a Lazair ultralight and they were marginal even after being rewound for more power. The Lazair is a really light aircraft with a huge wing area so it has very low power requirements.

It is an interesting read.

https://www.rcgroups.com/forums/showthr ... ric-Lazair
He actually did a quick test the other night and live streamed it on youtube. He was able to successfully take off and fly briefly, but I think he mentioned it was underpowered and he was going to add more motors (or something). He also had a pretty rough landing and damaged the fiberglass on the nose of the plane. He took the video down mostly likely because he did the test after sunset which is illegal for ultralights.

melodious
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Re: DIY ultralight, Retro biplane style, twinprop

Post by melodious » Tue Oct 31, 2017 5:28 pm

It flies! So far, he's using non lethal heights of 15-20 feet. It also steers, as he ran out of runway and had to turn back to find his home field. :lol: His battery's capacity really isn't enough to get anywhere. Not only will he need to increase his battery capacity, but will probably need to change to a more powerful engine setup as well.

What's funny is that battery could probably give my Ebike 50+ miles vs. his ~1 mile trial flight. But the plane wins the "best view" award for sure. :P

Surly Ogre rigid 29er, rear 10T MAC @ 50V 25AH & 40A: 30mph road/gravel/hill machine
42" dual diagonal Eskateboard @6s & 90mm wheels
Next: eMTB @10-12s & 8"-12" pneumatic wheels; Got Strapped? d-(',')z

melodious
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Re: DIY ultralight, Retro biplane style, twinprop

Post by melodious » Tue Nov 14, 2017 5:46 pm

Motors & propellers are the same. Added more batteries. He flies it higher & longer. Checks battery capacity after the flight. Informs viewers about ultralight protocol/regulation. I'm sure I've missed some other key points. :mrgreen:

Surly Ogre rigid 29er, rear 10T MAC @ 50V 25AH & 40A: 30mph road/gravel/hill machine
42" dual diagonal Eskateboard @6s & 90mm wheels
Next: eMTB @10-12s & 8"-12" pneumatic wheels; Got Strapped? d-(',')z

helno
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Re: DIY ultralight, Retro biplane style, twinprop

Post by helno » Tue Nov 14, 2017 9:07 pm

It will be interesting to see his in flight power measurements once he adds the instrumentation.

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