Ken,
  You should visit your local hobby shop and have a look at their SIG 
catalogue. Among all the wonderful items they carry, they have included 
several info sheets that provide just the info you need. They also include 
the prop shaft size along with the thread info. Super information to keep 
handy. 
  I have used a 7x4 on my OS .10 FSR, a 9x4 on my OS SF25, an 11x6 on my 
Webra Silverline .61 
  Hope this helps a little,
Steve
--- Maximus 2.02
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