[JFAIR] Small Flying Lego Machine

[Tamas Juhasz]

Hi!

I posted this moc a while ago in a specific topic as an example, but I never made an own moc topic for it.

JFAIR "contest" has "no rules", and the theme is about really flying Lego things, or things related to fly, so I think it's a good opportunity to present this moc:

http://www.brickshel...ry.cgi?f=500935

The machine has a very small frame (7L beam), and two propellers for propulsion:

http://www.brickshel...y.cgi?i=5432844

Here you can see it flying and raising:

(I don't know it's the first, or not, it just flies. )

I think a flying Lego machine can raise from it's own power. It's easy to throw or spin something with your hand. I made some experiments with pull back motors, because they are pretty powerful compared to their size and have lot of rpm, which is very needed to generate raising force.

So it can raise/flying off only with Lego parts. The motors with the base structure, the flying thing are all 100% Lego.

Yes, it can't raise too high (0,5 m max.), but the flying itself was my goal. Flying time is about 1 sec.

The accelerating unit contains two pull-back motors: http://www.brickshel...y.cgi?i=5432841

(I used these motors, because with (even with overvolted) Lego electric motors it seems, it's impossible to fly without wires between the ground and flying machine. And, If I use wires, then it's not a flying machine, because it's connected to the ground.)

The video was recorded with 600 FPS. We made some 1200 fps videos, but they have pretty low resolution. Camera: Casio EX-F1

Edited July 17, 2014 by Mbmc

[JM1971]

It does fly and looks fun, maybe there is a way to up the flight time so it gains more interest,

PS. those high speed cameras are so cool.

Edited January 13, 2014 by JM1971

[Blakbird]

Cool model on great high speed video! Nice to see that those propellers can generate a bit of thrust if spun fast enough. Looks like you made them counter-rotating to keep it reasonably stable. Personally, I would dispute the phrase "under its own power" because the power to make this model fly was actually supplied on the ground by another device (a pullback motor) which was in turn powered by a non-lego device (you). In this sense, it is more of a glider.

[Lakop]

Great! We used to make things like that in my school days but not with lego.

H

[Tamas Juhasz]

Personally, I would dispute the phrase "under its own power" because the power to make this model fly was actually supplied on the ground by another device (a pullback motor) which was in turn powered by a non-lego device (you).

Interesting point of view, thanks for sharing it. If I thought about this, I'd make a video about the pull back process with some geared down Lego motor. It's easy to make a simple machnism with Lego, which pulls back the motors, and when finished, it connects off. It would be more comfortable, it was pretty wearing to pull them with hand.

If I can innovate the flying part, I'll make this electric back pulling part also.

"Looks like you made them counter-rotating to keep it reasonably stable."

The two propellers turn in the same direction, that's the biggest problem with this, and the reason, why the whole flying thing spins after a while (this decreases the flying time). There is no inverted of this propeller. But other one would be too heavy, which can be inverted (built propeller).

Edited January 13, 2014 by Mbmc

[Phoxtane]

I think that shortening the axles that the propellers are attached to would buy you a hair more height and/or flight time. Are there any propellers that Lego makes that are inverted?

You may even be able to get away with one propeller, and use all four pullbacks geared up to spin the one axle. Then you get even more RPMs and less weight on the flying thing, and don't have to worry about counter-rotation.

Edited January 13, 2014 by Phoxtane

[Tamas Juhasz]

You may even be able to get away with one propeller, and use all four pullbacks geared up to spin the one axle. Then you get even more RPMs and less weight on the flying thing, and don't have to worry about counter-rotation.

That doesn't makes a lot of sense. That would be a single propeller. (before this I made single propellers to fly with these motors) I wanted to get a flying machine with frame/body and one or more propellers.

[JM1971]

Maybe some kind of launch assistance to help it along.

[Gee]

This is awesome!