Its Friday, I'm just going to leave this here

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Comment by Nikola Rabchevsky on April 29, 2016 at 7:51am

Is there an ICD-10 code for this because you're going to need it?

Comment by Rob_Lefebvre on April 29, 2016 at 8:37am

Ben,  there really is no control at all.

While Roll axis may appear to be roughly controlled, it's not.  I think what we saw in the video are the few times where he managed to maintain balance for a few seconds at a time.  It may be aided somewhat by ground effect, where the side of the rotor disk closest to the ground produces slightly more thrust than the far side.  At altitude, there is simply nothing which prevents it from rolling over entirely, no moment-generating method.

Pitch axis could be controlled by variable speed on the motors, but this will also couple with variable torque.  This is why it spins.

Yaw control vanes may help here, but I'm not sure.

The whole thing is a bit like riding a bull.  Only, the bull has swords.

Comment by Thomas Butler on April 29, 2016 at 1:30pm

First, get a helmet!  Oh yeah he's having fun; until his arm (or head) gets chopped off!

Those wild dismounts will be his end. Especially when his arm falls into the prop! Stupid!

Now lets start helping this fool improve his system rather than making pointless remarks.

He definitely is NOT flying and is riding an air cushion from ground effect...add an EPDM skirt and see how much better your HOVERCRAFT hovers.

To prove flight, he has to go about the ground effect...maybe six or more feet.

How about adding some skids to reduce those bouncy landings?

How about some screening around the prop opening to keep out wayward arms and hands...life saving!

Yaw control...that's a tough one...maybe a transverse mounted 12 inch pusher prop! i.e., tail rotor.

Happy flying!


Developer
Comment by Andy Little on April 29, 2016 at 1:56pm

You could twist the motors to get yaw... 


Developer
Comment by Andy Little on April 29, 2016 at 2:08pm

Just got to add that roll can be controlled by weight shifting.. After all a bicycle should fall over... but you learn how to ride it to stop it falling over. It looks as if this is similar

Comment by Maxime C on April 29, 2016 at 2:46pm

The way you can restore a roll moment on a bike is by having horizontal speed transformed in vertical moment by the mean of the wheel and floor friction and centrifugal force.  Apart from the ground effect mentioned by Rob, you can only on this system rely on centrifugal force, without the pivot point on a bike : way more unstable I guess.

It can be doable, the acceleration threshold that the motors should provide for it must be quite high though, pretty sure the system in the video cannot.

Comment by Maxime C on April 29, 2016 at 2:52pm

Trying to figure it out without pivot point it seems completely unstable : centrifugal force will apply on the aircraft COG no matter where it is moving with pilot position. And sheer centrifugal should not create any restoring moment.

Comment by Acorn on April 29, 2016 at 5:56pm
It's missing something. I just can't quite put my finger on it.

Developer
Comment by Randy on April 29, 2016 at 6:20pm

It's an impressive piece of work. I'm surprised he can fly it at all with, as others have said, pretty much no yaw control.

Comment by JB on April 29, 2016 at 8:31pm

Although I still find it absurdly dangerous, I'll add my few cents.

As per my previous comment it's not flying at all, its only WIG hover. It's likely to need a significant power boost to get it to "fly". But then flying at altitude will not allow for the current control methods (or lack of?) to work.

The natural progression for this design is to add some bits to gain yaw and roll control. And it's a configuration already been done by Malloy for their hover bike concept (and it has a decent BMW motorbike motor to boot):

Theoretically it would be possible to either make a fuel/electric hybrid or add variable pitch and drive train to a single motor, or even share the front/rear motors over two variable pitch props each.

But even though it is possible to make a hoverbike like this, I seriously question why create such a device that isn't optimized for fast forward flight.  If you really want to get some where fast and efficiently then you can't beat wings, especially if they can be tiny because you can use the hover capabilities as a airborne runway. Who wants to fly a slow "flying moped"? To add some speed put on some stubby wings, a pusher prop and make it a quadplane hoverbike! ;-)

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