Variable Pitch Propellor

This topic has 9 replies, 6 voices, and was last updated 14 February 2013 at 10:51 by Charles Marks.

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12 February 2013 at 23:14 #111933
Charles Marks
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@charlesmarks
Does anyone know of plans or designs for making a variable pitch propellor?

I am considering making one of about 2" to 2 1/2" blade dia.

My current thinking is that if I can make one then I can set the revs on a ST D10 and control direction and speed from one RC servo. In this way I avoid Stevenson reversing linkage and reduce chance of boiler running out of water due to engine manoeuvres (stopping/starting, low revs etc.).

Thanks,

P.S. I think I've 'searched' for an existing thread but have drawn a blank. If my searching is dodgy please forgive me and point me in the right direction.
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12 February 2013 at 23:14 #4084
Charles Marks
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@charlesmarks
Plans/Designs
13 February 2013 at 10:23 #111948
Chris Trice
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@christrice43267
Check out the tail rotors of any radio controlled model helicopter for ideas.
13 February 2013 at 10:47 #111952
JasonB
Moderator
@jasonb
Yes RC tail rotors would be your best bet . But not all use variable pitch these days the electric flight ones tend to have a variable speed motor so look at the glow powered ones.
13 February 2013 at 17:51 #111995
Charles Marks
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@charlesmarks
Thanks Chris and Jason for your prompt responses.

I have continued my rummaging in the WWW and come up with the following which others may find of interest:

http://steamtug.orconhosting.net.nz/ for plans/drawings and construction notes

http://www.avocetconsulting.com.au/modeleng/Boats.htm#_top for a photo of a different type

http://cnavale.quennetier.free.fr/spip.php?article17 for a very well engineered example but in French. I'd love to have the drawings for this one but it seems rather larger than 2 1/2 dia.

http://www.harbormodels.com/site08/info_pages/variable_pitch_2.htm for an advert for a commercial item, not sure if it's still made/available

page 114, 'Model Marine Steam' by Stan Bray for two photos and a paragraph.

If anyone has any other info I'd be pleased to hear from them.
13 February 2013 at 18:02 #111998
peter ravenscroft
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@peterravenscroft57700
hi charles

stan brays book on steam boats has a gearbox so that you can go foward and astern using 1 servo maybe be some help

regards

peter
13 February 2013 at 19:03 #112003
Durhambuilder
Participant
@durhambuilder
Another option may be a kitchen rudder.

http://en.wikipedia.org/wiki/Kitchen_rudder

type kitchen rudder into Google images for a few examples both full size and model.

Edited By Durhambuilder on 13/02/2013 19:05:31
13 February 2013 at 23:25 #112040
Charles Marks
Participant
@charlesmarks
Peter,

Thanks for reminding me of the gearbox option – possibly a fall back.

Durahambuilder,

Kitchen rudder is new to me. What a fascinating device. Effective control of speed, direction even in reverse and the nearest thing to marine brakes as your likely to find! Thank you.
13 February 2013 at 23:36 #112041
jason udall
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@jasonudall57142
?KORT nozzle?
14 February 2013 at 10:51 #112068
Charles Marks
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@charlesmarks
Thanks Jason,

Kort nozzle is another possibility but as far as I can tell the Kitchen Rudder achieves the same but without having to arrange for the propellor drive to be articulated.

Thank you.
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