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Parajet rubber mounts (prop)


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i must be missing something here... my prop doesnt have any rubber mounts???

where do they fit??.. my prop fits directly onto the reduction with bolts and spring washers??

or do you mean exhaust mount rubbers??

It is a parajet mod to stop prop vibration and it also pushes the prop back about 30mm to give a bit more clearance prop to frame

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ahhh.... i do use a 3 blade yes... but didnt get them with my 2 blade either??...

you need these guys http://www.gmt.gb.com/products/automotive-products/automotive-products.php

parajet buy the exhaust mounting rubbers from here (( well the exhaust ones have gmt written on them so i presume so )) ... i bought some myself slightly bigger than std to space the exhaust off the frame more as it was touching and vibrating... carefull to pick the right one, they do about 4 varying densities of rubber for the same mount!! or nylon

may get some myself and try the prop thing...as sometimes it feels like my fillings are gonna drop out!!

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My mod was the same as Toms (in the pic above) in addition there is a hard rubber surround that covers these six before the prop goes on.

My Macro also had prop to cage hits but Parajet sorted it out with this mod and l havn't had a prop to cage strike since.

IMHO if this mod isn't done to Macro owners they are liable to a cage/prop strike.

Yes the prop disc is slightly outside the cage circumference but as long as you have a clean take off and definately do not turtle you should be ok.

As for vibration, check all the obvious. Prop symatry, belt tension etc etc.


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  • 2 months later...

Have ordered 12 of these today direct from gmt, only need six but the postage was a flat £9 :shock: so seemed worth getting two lots

The part number is B30/15M820 68 M8x8 these were the highest load rated ones I could find.

I was giving my motor a once over yesterday while watching the rain out the window :( I had forgotten about the mounts and two of them were ready to fail :shock: one of my exhaust brackets had split in half aswell :( just goes to show the importance of regular inspection off ALL parts :oops::oops:

Tom :dive:

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i cant really backup what im saying here...

but i do feel more comfortable with the prop mounted directly to the reduction drive...i have concerns - probably unfounded about these mounts....

if the bolt went straight thru, then yes.. but i just worry about the steel coming off the rubber...and ... well you can imagine what could happen...

does anyone care to comment on this??,,,if only to put me at ease!!!

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I don't think failure under normal operating stresses is an issue as the loads involved are split across 6 mounts. (as long as they are in good condition*)

The issue is making sure they get inspected regularly (before every flight) this is not a problem for me as I have to break my motor down to fit in the car so I can inspect them then.

Not scientific I know :D

Tom :acro:

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Aslong as it isn't spinning, being pulled over backwards (turtled) shouldn't break your prop. I've done it twice. Once photographed or filmed in that pose ( by a gloating friend) you will feel determined not to let it happen again. Or get a quick release harness so you can escape before the camera starts to roll


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  • 3 weeks later...

Ok I have binned the rubber mounts for good.

Several people including my old man who is an airworthiness engineer for the laa have pointed out that having rubber mounts holding a prop on really isn't a good idea.

Solution... I turned up a spacer to get the same offset as the mounts and got some M8x90 stainless bolts to go straight into the hub.

Pete B has put the idea off a quick release system into my head so may look at machining something up along those lines.. cheers Pete :D:D

I still have the rubber mounts if anyone wants them for another purpose?


Tom :D



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