Self-launching sailplane conversion

Things that fly
SlowCo   10 MW

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Re: Self-launching sailplane conversion

Post by SlowCo » Aug 31 2022 11:08am

Very nice. Hope it will get you up safely in the air soon. How will the prop be positioned correctly to be able to retract it back into the hull?

AC5ME   10 mW

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Re: Self-launching sailplane conversion

Post by AC5ME » Aug 31 2022 12:08pm

The electronic braking provides about 15lbs of force measured tangent to the rotor, I'm hoping this will be sufficient to prevent windmilling but I don't know until I do some flight testing. I have a mirror in the cockpit to verify the prop is vertical, I hope I can rotate the motor slowly enough to stop it there reliably.

SlowCo   10 MW

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Posts: 2197
Joined: Jan 05 2015 5:43pm
Location: The Netherlands

Re: Self-launching sailplane conversion

Post by SlowCo » Sep 01 2022 2:54pm

I hope you'll make a video of the first flight and post it here. Very interested.
And if you haven't seen this thread already it is worth reading: viewtopic.php?f=30&t=113852&start=125

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red   10 mW

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Re: Self-launching sailplane conversion

Post by red » Nov 13 2022 10:06am

AC5ME,

Sorry, I can't help with the actual conversion, but you seem to be on-track. I send best wishes. I have some input that you may want to consider.

For the flight testing, I am hoping that you can tow up in the usual sailplane manner, and then conduct your performance testing while airborne, with no need to test the self-launching aspect on a do-or-die basis at first.

Assuming you are familiar with "Ground Effect," I would suggest a very long runway for testing, maybe even with enough length to launch and land without turning, if necessary. Build up some excess airspeed in Ground Effect, before commencing the initial climb.

In case your prop-stopper does not work as expected, you may want the ability to lower the motor and prop almost down to the fuselage, and have it held there. This trick may allow the prop-stopper to operate as it should, if it did not do the job with the power pole upright. A mechanical prop-stopper (made from flexible plastic) may do the job for you, if needed, but use that option only if all else fails. Once the prop is stopped, you can lower the motor and prop completely.

Seems like you will be making heavy demands on the batteries, on a continuing basis. I would want a sailplane parachute on my back as a matter of routine, but that's just me.

Interesting project. Best wishes. Please keep us posted.

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