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Rotary Wing
Discuss helicopters and other rotary wing aircraft from any era.
Animating the blades of an MRC HTL-4 in 1/35
pnance26
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Member Since: January 22, 2016
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Posted: Friday, October 05, 2018 - 06:58 AM UTC
Thanks, everybody for all the ideas!

I found a very teeny tiny small motor that may work for the rear rotor. I will have to build some kind of hiding device... and then again, it may still be too large but I will have to way and see.

Also, there is 1/16" aluminum tubing that the wire can run inside down the top of the tail boom to hide that mechanism.

I just ordered all of it so maybe next week we can resume.

There will be a main rotor motor and a tail rotor motor. I know they should run in synch but this may be the best I can do!

Will post photos as I go along!
HeavyArty
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Posted: Tuesday, September 11, 2018 - 09:57 AM UTC
Another option is to put a motor on the main rotor, and simulate the tail rotor with a clear disk with a couple blurred blades to simulate motion. The tail rotor spins much faster than the main rotor anyways. Aircraft modelers use the disks all the time to simulate props in flight.





Apparently some companies make PE prop blur pieces too.




Here's one as a tail rotor.
Jessie_C
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Posted: Tuesday, September 11, 2018 - 08:41 AM UTC
The real helicopter has a 45 degree gearbox at the 'bend', and a 90 degree gearbox at the tail rotor. both of these have pretty much a 1:1 gear ratio. I really doubt that there's very much in the RC world which can be in scale. 1/35 is extremely small when compared to a flying model. You may need to make your own out of watch parts or the like.
pnance26
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Posted: Tuesday, September 11, 2018 - 08:40 AM UTC
That's the one!

Thanks for the photo!
HeavyArty
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Posted: Tuesday, September 11, 2018 - 07:23 AM UTC
I have used small motors and gears to animate both a 1/32 UH-1D and AH-1G. These had room to hide all the components inside the fuselages.

The main issue is that the Bell HTL-4 (Bell 47/H13) has no fuselage to hide the parts (second motor, gears, rubber bands, etc.) for the tail rotor. My guess would be some parts from a small drone or radio controlled mini-helicopter may work. You will need to find a small shaft that can be the tail rotor shaft and a 90 degree gearbox for the rear as well.

USCG/USN HTL-4
Kevlar06
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Posted: Tuesday, September 11, 2018 - 06:19 AM UTC
Patrick!! Where ya been buddy?!? Well, you could use the gearing and motors found in those tiny RC drones. Or you could use a separate motor wired into the tail boom-- perhaps a telephone pager motor-- (vibrator) which are tiny. Another option might be to use two rubber bands, one the length of the boom, the other shorter to accommodate the 45 degree angle to the rear rotor shaft, with a transfer pulley. I've been contemplating motorizing a twin rotor CH47 for some time now, and the weight requirements mandate I use a telephone pager motor (vibrator) so I think I've settled on the rubber band method to eliminate weight--(reduces the motor and wiring components from two motors to one). If the boom is open, which I think it is on your model, you could just rig the rubber bands to brass prop shafts of the correct diameter replicating the kits prop shaft. You can make a lot of neat stuff using K&S brass tube. Good to see you back!!
VR, Russ
pnance26
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Posted: Tuesday, September 11, 2018 - 03:59 AM UTC
I hope I can mine the collective for some advice... and I know there are very few brand new ideas in modeling ever, so here goes.

I have an MRC 1/35th scale Bell HTL-4 with pontoons. I would like to animate the main and tail rotors and I understand they both are driven off one main shaft so they spin in synch.

I have obtained a Tamiya motor that fits perfectly inside the "motor" housing on the kit. So the main shaft is ok. But here is where I run into problems.

1) I need to make the tail rotor shaft rotate which I understand the engineering needed to do that... but the tail rotor is not straight out from the motor on this particular helo. It has a 45 degree bend from the main tail shaft up to the rotor itself so...
2) Is there anything in an "off the shelf" cheap RC helo that I can use to accomplish my goal and
3) What scale would 1/35th be in the RC world?

I would love all the input and feedback anyone can give. I am in no hurry so fire away!

Thanks in advance!