Graupner CAM folding prop - RC Groups
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May 11, 2006, 09:18 PM
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jbrandon's Avatar

Graupner CAM folding prop

I recently purchased a Graupner CAM folding prop and assembled it and have found the blades quite stiff when the shoulder screw is tightened to a reasonable amount, donít know exactly how much. But when I feel it is tight the blades are very stiff and I am afraid they will not swing back when power is off.

I have sanded some on the pivot of the blade but am afraid to take too much off.

Just how much can be taken off to reliable folding? Or should I even worry about the stiffness?
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May 11, 2006, 09:37 PM
Registered User
Just be sure it is a 8mm hub set/ 8mm root thick bladesset you got.( cos some spinner comes with 6mm wide hub set and Graupner produces some 6mm thick root blades as "gear prop')

Don't worry about strength after bit of sanding, +/=0,0xmm is not a problem.Just make it to dangling freely.
Even in my some 2000w power set up, I need to sand a bit to fit blades to rfm spinner set.
For extra assurance, you may add a bit of thread lock glue on the bolts which go through the blades.

May 11, 2006, 09:42 PM
Registered User
Normaly I would not reply to this post, as I have heard from you before. (pantera)
put some blue locktite on the threads, and tighten only till the blades start to
offer a little drag, they should be almost able to flop back and forth !
the blades will self center on there own. At this very moment I am working on
my tenth glider, a bandit, and all the props are set up the same.
May 11, 2006, 10:03 PM
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jbrandon's Avatar
Thanks for the information...
May 12, 2006, 06:48 AM
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Andy W's Avatar
Yup, loctite on the threads, and tighten until they just start to bind, then loosen up a little.
May 12, 2006, 11:46 AM
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pilotpete2's Avatar
Hi All,
One point to consider, if this is a Graupner plasic hub where the screws for the blades thread in the plastic, don't use Loctite
May 20, 2006, 08:38 AM
Registered User
hellow I had same problem with my prop and being new to the game i had no idea what to do? so i just gave the screws a pinch until the props folded back ok. I had a few flights all was ok when on the next flight I heared a loud noise, the glider was quite a height and the noise only happend under power? so i landed and found no canopy and one blade missing, also the servo tray loose The model had vibrated itself silly due to the prop all seems common sence now to use some lock tight on the threads but to a newcommer who flies on his own not all is so clear?Idont know why the manufactures dont give some advice on there products you would think it would be in there interest. Oh and by the way there is the cost of the model only £500 Quid and i cant afford to loose that sort of money for the sake of a drop of thread lock.
May 20, 2006, 03:26 PM
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Tony Oliver's Avatar
It's only a hinge pin you're putting in. All you need to do is screw it home - don't tighten it up at all. I put a dab of PVA glue in the screw thread which sets slightly rubbery and never comes loose. It needs only slightly more pressure than usual to remove the bolt.
Last edited by Tony Oliver; May 20, 2006 at 03:32 PM. Reason: finger trouble
May 20, 2006, 07:42 PM
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pilotpete2's Avatar
There are many style folding prop hubs, some are garbage, the good ones like Freudenthaler Aeronaut use machine screws with nylock nuts, so that you can set the blades so that they are free with no slop, but the screws won't loosen and throw a blade.
I like Tony's idea of using the PVA where the bolt threads in to the yoke, but Loctite is risky being used around plastic, like the blade shoulder Locktite destroys most plastics that it comes in contact with, and it doesn't take much.
May 20, 2006, 08:40 PM
Registered User
Will the LOCKTITE really corrode the Graupner CAM??? Never heard that before and I use RED locktite on ALL of my prop set, not a trace of corrosion had been seen. Or are we talking the same thing? --Graupner CAM.
I think Locktite the bolt end part is really IMPORTANT, I just had a blade being thrown from a rfm twisted spinner / stratairs 17x19 in my RW yesterday, LUCKILY it happened at the end of motor juice. MORE LUCKS indeed I could spot the tiny blade in the shrub ONE PIECE, and so is the plane.<besides sheer LUCKs, I use 7cells on this plane is somehow the cause of the lucks, I had experienced 2 other similar cases, but in 8S power combo, no lucks>
Ok, btt, will those Locktite corrode plastic/ carbon filled nylon...?

May 21, 2006, 01:28 AM
Slope and thermal
I use Graupner CAM folding prop (the CFK version).

The prop hub is metal with a metal screw. Put in the screw but do not tighten at all. The prop should flop back and forth. Use a single drop of blue loctite to stop the screw from coming out. The loctite should not get onto the prop plastic at all.

What I do is:
- First engage the screw so that only one thread turn holds it on for one prop blade side.
- Apply a single drop of blue loctite to the quite deep hole with the srew just in it.
- Do up the screw but do not tigthen.
- Use some tissue to soak up the loctite that was pushed out of the hole by the screw.
- Repeat on the other prop blade.
- Wait at least 24 hours before turning on the motor
May 21, 2006, 10:50 AM
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pilotpete2's Avatar
I really don't know if Loctite will hurt the CAM blades, I just am very cautious about using it near any plastic. I have never used Graupner hubs other than the cheapie plastic ones where the spinner keeps the screws from backing out. As I mentioned in my earlier post, I use the Aeronaut style that use a nylock on the bolts, they have never loosened on me in years of use

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