Lego Technic aircraft engine and landing gear prototype

[Andy G]

Hey folks,

Just testing the retractable langing gear system with the engine operating. The propeller pitch control isnt hooked up so I manually change the pitch. havent posted for ages as I had to completely rebuid the wing structure. Really tough to support the nacelle weight. The centre wing box/fuse area needs to be very strong and this took some work, specially given the dihedral angle

Its been hard to build the landing gear perpendicular to the ground given the wing dihedral, but it seems okay now. Gear system is the same as my last video pretty much, but it folds up neater with the downlock actuators on the drag brace.

Andy

[Lost_In_Noise]

This looks to be working properly. How much air pressure does the props generate? Could you make something fly away with it?

[Alasdair Ryan]

Nice prototype,I like the landing gear design.

I cant see that design of lego plane flying in the air,as it has too much weight and also not enough lift.

[Carsten Svendsen]

That looks good. It seems to be really compact, would it be possible for you to take a close-up photo?

[Someonenamedjon]

It looks really good, especially the landing gear!

[Lakop]

That's so good it's frightening.

H

[Someonenamedjon]

That's so good it's frightening.

H

:P

Edited March 12, 2013 by Someonenamedjon

[Andy G]

I

I've been slowly working away on this model aircraft shown below since 2011, but one thing I have been stuck on was how to control the variable pitch propellers remotely. Remote control is required so that only the minimal weight is placed on the wings as a four engine turboprop with a pneumatic gear already has a lot of weight (each wing is 1 kg). I tried using closed loop pneumatics but the compressibility of air meant there was no fine control. Linear actuators would be impractical due to the long drive trains.

Closed loop hydraulics is much better-very fine control with really quick response. Also, because no angular loads are placed on the hydraulic master and slave cylinders there is very little leakage of air in or water out once the system has been bled of air-hence the system stays “rigged” for a long period of time.

I am thinking of attaching a rotation sensor of some type to the motor as a mindstorms sensor. Then, by hooking up a mindstorms motor to the pitch control master cylinder I will be able to produce a fully governable aircraft motor that has similar operational control modes as a real one (reverse, cruise, taxi etc)

Anyway-one day it will be finished!

[dhc6twinotter]

My Piper Super Cub uses a variable pitch mechanism that uses a differential to adjust pitch. It works very well and is very precise, especially if geared down a bit. Might work for your application.

[DrJB]

Looks very nice. While your post is about a certain part of the plane only, would it be possible to share pics for the rest-of-the-plane? Looks like you have a large structure/skeleton, and some of us (I) are rather curious.

Also, as pointed to by dhc6twinhotter, would be interesting to see more of the mechanism that changes the blades pitch.