Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

K&B 7.5 DF prop

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Old 04-01-2003, 06:05 PM
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JeffH
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Default K&B 7.5 DF prop

I have a k&b 7.5 cc df engine that I am putting on a Whiplash. What do y'all think is best for this combo. Also, what pipe length with that associated prop. While in the fan, I turned the motor 24,500 peak and flew at 23,500. I doubt if I will get a prop to turn quite that fast and still have enough low end grunt to get the plane flying from the hand launch.

any help would be appreciated!
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Old 04-03-2003, 01:04 PM
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MMallory
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Default K&B 7.5 DF prop

Jeff,

You want to keep the R's up on that engine. I have one on my Dust and it turns over 21k on the ground. Launching isn't a problem with the Dust. For the Whiplash you will want someone to hold the plane overhead and gently push it forward and level. Once the plane is trimmed you can go with the Frisbee type launch.
A good starting prop should be in the 8x8, 8x9 range.

Mark M.
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