Monocopter

[mi-nan]

I seen a monocopter on the web recently and it got me thinking. I have a set of r/c helicopter wood blades. Would one of them work for a monocopter? Here are a couple of pictures of the finished project just before launch. I flew it on a G-33. I didn't account for the centrifugal force on the motor tossing the case when I friction fitted the motor. I found the case and I plan on trying again. The second tube houses a parachute.

 

[Lentamental]

Looks good. My only question is why use a parachute? The whole point of the design is that it inherently helicopters, so doesn't need a separate recovery system.


As for monocopters, I have had some very mixed results. My first one, copied straight out of the NAR handbook a few years back, absolutely sucked. It went up 10', and over 20', nearly hitting the people loading their rockets on the next set of pads. I then took that design and totally rebuilt it, building up an aerofoil around some central struts, streamlining the nosecone, cutting down the weight by 30%, and generally making the whole thing much more aerodynamic. The result was spectacular, flying up at least 100'. However, when I went back to launch it again this past month, after 5-7 years of sitting in my closet, it did not fare so well. it took off at a pretty serious angle, flying right over the crowd, and falling to the ground with several seconds still on the ejection charge. It landed pointing the engine straight at a small child :y: luckily when it spit the engine it missed...

 

[mi-nan]

The bigger monocopters I have seen on video fall out of the sky like a stone when they stop spinning. The don't really auto rotate so I used a parachute to help slow its decent.

 

[troj]

The bigger monocopters I have seen on video fall out of the sky like a stone when they stop spinning. The don't really auto rotate so I used a parachute to help slow its decent.

I think it depends a lot on the design of the monocoptor, as well as the materials they're made of.

Ed Miller sells a monocoptor kit that does one of two things -- sometimes it auto-rotates back down, and sometimes it flutters back. Either way, it recovers safely without a parachute.

But, it has a good-sized "wing" that's made purely of light balsa. Your helicoptor blade is likely a lot more dense, in addition to not being large enough to generate much drag on the way down, so the parachute is a good idea.

-Kevin

 

[JAL3]

The bigger monocopters I have seen on video fall out of the sky like a stone when they stop spinning. The don't really auto rotate so I used a parachute to help slow its decent.

A guy in my club, Ken Kryzak, is a monocopter enthusiast. His usually autorotate or flutter down. Some of his more recent designs use changing pitch to accomplish the autorotation.

This is one of his older ones on a G33. It had about a 5 foot span and fluttered down: https://www.flickr.com/photos/23694991@N03/2953710058/

A more recent effort used a cam to change the pitch. an explanation of it is here: https://www.flickr.com/photos/23694991@N03/3957063377/in/set-72157608222928932/

I really like this last one but the pin sheared on takeoff making for an exciting time. :y:

 

[rstaff3]

You must have built it strong. My experience with a G-powered monocopter, despite epoxy and carbon straps, resulted in re-kitting. Good job.

I agree that a chute shouldn't be required. However, I've built and watched a lot of them and very few actually autorotate back down. My philosophy in rocketry says that, just because you don't need something doesn't mean, you don't want it

PS - Anybody wanting to get into monos should take a look at Art Applewhite's products.

 

[JAL3]

PS - Anybody wanting to get into monos should take a look at Art Applewhite's products.

I'll second that! His Helix line is very simple but works well. Then he has some others as well including plans for an MMX version.

 

[kramer714]

https://www.youtube.com/watch?v=qiLpPQXSO7g

The will continue to fly if you have a good balance weight on them. Mine flies from a G and keeps spinning all the way to the ground, graphite airfoil, graphite counter balance and fiberglass motor tube.

I think an RC blade would work well!

 

[JAL3]

https://www.youtube.com/watch?v=qiLpPQX

The will continue to fly if you have a good balance weight on them. Mine flies from a G and keeps spinning all the way to the ground, graphite airfoil, graphite counter balance and fiberglass motor tube.

I think an RC blade would work well!

Clciking the link is giving a "malformed Video ID error" from YouTube.:confused2:

 

[kramer714]

fixed the link

https://www.youtube.com/watch?v=qiLpPQXSO7g

plus picture