Arplast Prop - Question

[rehler]

I received my new Arplast prop for my Rotax 912S engine, which is the same used on the Magni gyros. The bolts are 8mm but the holes on the prop flange that line up with them are 13mm (way too big!).

Are there some bushings used to fill the gap around the bolts? If so, where do I get them - from Rotax or from Arplast?

Or is there some other way to attach the prop hub?

Ken

[rehler]

Thanks to Greg Gremminger I got the answer (six expensive special nuts sold by Rotax). I don't know how anyone can build a gyro without the help of the people on the Conference. This is wonderful.

[mceagle]

The special nuts are actually driving dogs for the propeller. They take away the shear loads from the bolts and give a much larger surface area driving contact.

[rehler]

Tim,

The "driving dogs" are a great idea. After I saw them in the Rotax catalog I could see what they were and how they worked.

Now I have to drill out the holes in my prorotator drum from 8 mm to 13 mm to fit the driving dogs. Nothing is simple, but I am looking forward to getting back in the air soon. It's been 7 months since my last flight - when my crank shaft broke in October!

[Doug Riley]

Warp Drive sells the drive bushings for the 912/914 -- at least they do if you buy a prop from them. Don't know if they'll sell them as a stand-alone product.