making 2 helicopter rotors spin

[JohnsLegos]

I had put this in another forum on this site but had no responses so I thought I would put it here to see if any one can help. I have these 2 Lego helicopters and want to make the rotors spin using the motor in the front. I put the "gear wall" up using 1x16 Technic beams to see if it would work just for a laugh but I am thinking in the chain direction. The copters are spaced far enough apart so the rotors do not hit and will be secured to the baseplate with bricks so they do not move around. Any thoughts on this? Thanks. 

 

[Milan]

What's the actual question?

Right now, you can improve it by bracing the gears from the other side, too, with another "wall", and let their axles have supports in the both walls.
I would also build a wall/support block under the tail of the left helicopter, right under the gear, and all the way to the base plate. Otherwise, it may shake too much.

[msk6003]

And I will use other moter like PF M,L, C+ M,L. Those 4.5v motor is to weak for that gear wall.

 

[MinusAndy]

Could you not use a pf m motor directly on each rotor? It looks deep enough.

[JohnsLegos]

I am looking to do this at a train meet here in November (I am doing a n all Lego train with different Lego kits in the middle) and do not want the rotors to spin super fast. I just want to show that they rotate. Would 1 pf motor and some chain make them spin slower? And Milan, I was thinking of that too on securing the rear of the big copter down. If I move the gears as shown it pulls it down towards the baseplate a little bit.

[Milan]

19 minutes ago, JohnsLegos said:

do not want the rotors to spin super fast. I just want to show that they rotate. Would 1 pf motor and some chain make them spin slower?

They will rotate according to the gear combinations you use, and the type of motor you use.
If you want slower rotation, you need to make combination of gears in a way that a smaller gear engages a larger wheel (for example an 8t gear engages a 24t gear, which gives you 3 times slower rotation, but also 3 times more power).
If you want faster rotation, do the opposite.
The gear combination you have now will probably rotate them too fast, since you are engaging bigger gears to smaller wheels.

I would suggest to just try and attach the motor(s) you have now, and see how it works. Then we can adjust it until you are happy with it.

33 minutes ago, JohnsLegos said:

If I move the gears as shown it pulls it down towards the baseplate a little bit.

Yes. And it will get worse when they are powered by a motor.

[Jurss]

I would put axle on the long side, and use these to "turn" rotation in needed direction.

[JohnsLegos]

10 hours ago, Milan said:

They will rotate according to the gear combinations you use, and the type of motor you use.
If you want slower rotation, you need to make combination of gears in a way that a smaller gear engages a larger wheel (for example an 8t gear engages a 24t gear, which gives you 3 times slower rotation, but also 3 times more power).
If you want faster rotation, do the opposite.
The gear combination you have now will probably rotate them too fast, since you are engaging bigger gears to smaller wheels.

I would suggest to just try and attach the motor(s) you have now, and see how it works. Then we can adjust it until you are happy with it.

Yes. And it will get worse when they are powered by a motor.

How about using a chain instead of the gears. The photo with the gears was just for a laugh....

[Carsten Svendsen]

3 hours ago, Jurss said:

I would put axle on the long side, and use these to "turn" rotation in needed direction.

This is by far the best option. Just use axles, it's less friction and more quiet than a train of gears or chains

[Milan]

7 hours ago, JohnsLegos said:

How about using a chain instead of the gears. The photo with the gears was just for a laugh....

You can use gears, chains, or as Jurss suggested, a long axle with two perpendicular gears at the end, to reduce friction as much as possible.
Using just a chain wont give you much room to make a reduction system, so the rotors may end up rotating too fast. You can put a reduction system just before the helicopter's input, though.

[JohnsLegos]

7 hours ago, Carsten Svendsen said:

This is by far the best option. Just use axles, it's less friction and more quiet than a train of gears or chains

The part shown in the photo, would that work with the small motor in the opening photo?

[Carsten Svendsen]

15 hours ago, JohnsLegos said:

The part shown in the photo, would that work with the small motor in the opening photo?

You don't need this part if you don't have it, just build something with technic bricks and use 12T bevel gears. Same thing.