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Old Oct 06, 2002, 01:41 PM
razor burn can be good
RCZohn's Avatar
aurora illinois
Joined Aug 2002
314 Posts
help on graupner folding prop

ive been building a python and just picked up a graupner 6x3 folding prop and spinner combo for it

the question i have is that after assembling the prop on the plane and pulling out the folding blades, the blades dont fold out all the way and form a straight line instead they make more of a vee with an angle of about 160 degrees or so.

is this the way these props run or do i have to loosen up the cone so the blades swing out more(i have done this but it pulls the cone away from the base thats attached to the motor shaft when i do this)

this is my first plane with a folding prop so i am not sure what to do
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Old Oct 06, 2002, 06:15 PM
razor burn can be good
RCZohn's Avatar
aurora illinois
Joined Aug 2002
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??
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Old Oct 06, 2002, 07:11 PM
3D Wannabe
Kamloops, B.C. CANADA
Joined Jul 2002
609 Posts
RCZohn,

That's pretty much the way mine is on my Terry and it flies great. I don't know what the degree of the props is but they do form a very shallow v when turning even at WOT. Hope this helps you.

Kevin
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Old Oct 06, 2002, 08:04 PM
razor burn can be good
RCZohn's Avatar
aurora illinois
Joined Aug 2002
314 Posts
thanks for the input, anybody else out there got an opinion??
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Last edited by RCZohn; Oct 07, 2002 at 05:08 PM.
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Old Oct 07, 2002, 05:19 PM
razor burn can be good
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aurora illinois
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Old Oct 07, 2002, 07:49 PM
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bosley's Avatar
United States, CA, Twentynine Palms
Joined Jun 2002
1,191 Posts
i HAVE THE SAME PROP AND IF YOU RUN IT AT MAX RPM WITHOUT THE SPINNER IT WILL STILL FORM A SHALLOW V. NOT SURE WHY BUT IT MUST BE INTENTIONAL BECAUSE IT WORKS REALLY WELL.

BOZ
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Old Oct 07, 2002, 08:35 PM
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Craig Logan's Avatar
Manchester, TN USA
Joined Nov 2001
217 Posts
Centrifugal force slings the blades out to their running position, which as bosley points out may be observed without the spinner in place to be somewhat angled back. The airfoil lift force which one would intuitively assume to be strong enough to "pull" the blades to the bottom of the spinner slot is actually very small compared to the centrifugal force slinging the blades outward.

You'll find that the prop works just fine in flight without the spinner, albeit not as streamlined. You'll also find that if your plane has no landing gear and you occasionally ground loop the plane on landing that the spinner slots will eventually crack due to the prop catching the ground and pulling hard against the spinner.
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Old Oct 08, 2002, 05:11 PM
razor burn can be good
RCZohn's Avatar
aurora illinois
Joined Aug 2002
314 Posts
thanks for the advice
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Old Oct 08, 2002, 05:25 PM
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Mike Smart's Avatar
Aylesbury, Buckinghamshire, Great Britain (UK)
Joined Jan 2000
3,036 Posts
RCZohn,

You can always open out the slot in the spinner a little deeper with a modelling knife. I have done this before without any problems.

Mike
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Old Oct 08, 2002, 06:34 PM
razor burn can be good
RCZohn's Avatar
aurora illinois
Joined Aug 2002
314 Posts
i thought about carving the windows in the spinner but was leary bout that ,fearing uneven cutting and uneven blade angles
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Old Oct 08, 2002, 11:21 PM
3D Wannabe
Kamloops, B.C. CANADA
Joined Jul 2002
609 Posts
Mike,

Great tip, I'm going to do that with mine before I fly it next. Thank you for the wonderful idea.

Kevin
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