How to motorise 1/72 Tu-95 Bear engine?

[Dermo245]

Hi everyone,

No, it's not April 1st! This is probably a shot in the dark but does anyone have any experience of knowledge of motorising props on a 1/72 model?

Me and another modeller are planning an F-14/Tu-95 diorama build where the Tomcat intercepts the big Bear. For the Bear, we were thinking of motorising the props....just to make it more difficult for us!

Clearly, the contra-rotating thing only addsmassively to the difficulty...so we might go for a single motor instead (and just power one set of blades)

Any ideas on types of motor to use or set up would be really appreciated.

Thanks in advance,

Dermot

[Alex Gordon]

There was something in Fine Scale Modeler (American spelling...) a few years ago where one of our chums used a mobile phone vibrator motor minus the eccentric weight to drive the propellor on a 1/72nd scale Spitfire.

I don't know if these can be sourced from Maplin or RS or the like but this might give you a start.

[Dermo245]

Thanks Alex.

Think I might have that issue....will dig it out of the library!

Cheers,

Dermot

[Rob G]

Trumpeter's 1/48th Westland Wyvern uses a small planetary gearbox to drive the contra-props (Turn the front one by hand, rear one goes the opposite direction. Kinda cool.). There may be something similar available online. Remember that you can extend the shafts back into the nacelle, so you won't have to cram it all in behind the prop. Flexi shafts are an option, as well, if you can't get a straight line to the prop drive.

EDIT: After a mission involving deep stash diving (I must admit to not expecting to come back), I dug out a 48th Wyvern and a 72nd Trumpeter Bear... the 48th g/box fits into the Bear's nacelle with room to spare. There'll need to be some engineering done, but nothing that couldn't be conquered. I'm not sure how good Trumpeter are at replacement parts, but they may be worth approaching.

For the record, the nacelles on a 72th Bear are huge. Lots of room for all sorts of gubbins. If you want photos, I can manage that.

Edited November 21, 2014 by Rob G

[Dermo245]

Thanks Rob and that's really helpful. I drew the long straw on this and I'm building the other 'half' of this build - my colleague (lucky him) gets to do the engines!

Will see how we get on with Trumpeter...nothing ventured, nothing gained and all that!

Thanks too for the deep stash dive...I know how much fun the can be...

All the best,

Dermot

[Rob G]

I've been looking around, because I love contra-props... Instead of waffling about with planetary gearboxes, a possibly better option would be to use 2 motors, running direct to the props. That would simplify the engineering a lot.

Or, even more simply, one motor with an extended shaft, gears on the each end - the inner prop shaft is driven from the rear gear.

These are R/C aircraft threads, but they've got some good ideas...

http://www.rcgroups.com/forums/showthread.php?t=661210

http://www.rcgroups.com/forums/showthread.php?t=246407

Edited December 4, 2014 by Rob G

[Dermo245]

Nice one, thanks!