Aircraft gearboxes in a boat?

[Shaun Hendricks]

Cruising around allerc for another thread and found these. Anyone try anything like them in a boat?

http://www.allerc.com/product_info.php?cPath=26_56&products_id=1196

That one can swing a 14" air prop. What about turning a 4" boat prop with it?

Nice an inexpensive at ~$20. Looks like it has several mounting points and techniques.

Being dual motor, backup in case of failure?

Just musing here.

[pimp_squeak]

Can't say I have any experience using aircraft gearboxes in boats, but unless you put a thrust washer/bearing in your stuffing tube, wouldn't you have issues with the thrust bearing in the gearbox because the force will be opposite what it would be in an aircraft (pushing the boat, rather than pulling as it would be in an aircraft)

[More HP]

I've been using one of the small hobby lobby gearboxes with ball bearings and a 280 motor in a small scale boat with great results!

I haven't had any prop shaft rubbing or thrust problems, but it's not much of a stump puller anyway, just a frog chasin' play boat.

[Rob_P]

Pimp,

I'm not sure what you are getting at here, any prop shaft thrust issues need to be addressed before the UJ connection to the motor. The motor is only concerned with providing rotation. Any built in thrust bearings in the motor would have no effect.

I have recently looked at using a more simple GWS unit in a boat application (They are great prices). The problem that stopped me moving further was the threaded output shaft on the motor which may need to be replaced in order to fit a conventional UJ. This takes away any price advantage you thought you had.


I'll try and post a link to the dimensional diagram.
http://www.gws.com.tw/English/product/powersystem/028.htm#EPSD-350%20C

Link does not quite work, you need to scroll down the page and click on the diagram

Teh hee....
Look out this wiring note at the top of their page:
RED = High voltage boosts power , but fatally damages the motor


EDIT - Thinking about it now, maybe you could live with the threaded motor output shaft and just thread the bore of the motor side UJ to suit, screw on and then back up with a lock nut.... Just rambling...

[Shaun Hendricks]

I'd probably just cut the threads off or flatten them and attach the u-joint anyway.

Interestingly enough, once you know the threads you could make them work for you by making your own 'wire drive' connector for the threaded end. Setscrew or locktite and you have instant flexible driveline. No U-Joints need apply.

[keith S]

I have used the Master Airscrew units in boats before to run my destroyer and a Dauntless. Worked really well for both to get to speed and for throwing the 5 bladed 2.5" props on the Burk destroer.

[785boats]

Rob_P.
You can buy the brass splined inserts for those red U joints already threaded from 1.6mm to 6.0mm. I think a range of imperial threads is available too. Don't know the brand or where you can get them over there but our LHS sells them here. I find that they have less noise & vibration than the grubscrew type.
All the best.
Paul.

[LtDoc]

Shaun,
Would it work? If you need to gear-down a too fast motor, I don't see why not. I sort of doubt if that second motor is for 'back-up' in case of failure. It's more likely to provide additional 'power', as in using two small ones instead of one larger one? Hey, if it works, it works! Who cares what it was supposed to be used for?
- 'Doc

[boat_builder]

I too have used the Master Airscrew units like Keith S. They have worked really well for me and another one of my other boating buddies. :)