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

Need 9.5X8 or 10X8 Prop 30K RPM

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Old 08-30-2006, 08:12 PM
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rcflyer1970
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Default Need 9.5X8 or 10X8 Prop 30K RPM

I need 9.5X8 or 10X8 Prop 30K RPM, I'm finishing a scratch build prop jet, I have a new OS77DF engine going in it, first run it turned a 9.5X7 Pylon D1 at 25K on 10% on the bench, it sounds under proped slightly at least with the stock pipe length, anyone know where to find larger hi rpm props?
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Old 08-31-2006, 11:31 AM
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Default RE: Need 9.5X8 or 10X8 Prop 30K RPM

That sounds a lot under-propped....

For prop-jet use I'd probably lug that engine down closer to 18-20K rpm ground peak. It all depends on your pipe length and prop selection.

Any of the APC D-1 series props would likely fit the bill....

8.8x8.5 8.8x8.75 8.8x9 8.75x8W 8.75x9W are worth trying.

For a bit bigger blade, try LP09580 9.5X8N


However, a word of caution. All of these props regularly turn over 20K rpm in flight on the Q-500 engines. I believe that 23000-25000 is probably not a huge problem.

Most definately do NOT spin any of the APC C-1 or C-2 series 9" or 10" props anything close to 20K rpm !!! However, with great caution

In the past, some folks have utilized the 11 and 12" props, clipped in diameter. At least this way the prop hub is much larger. Approach this method with extreme caution.

However if you seek to go anything much over 20000, I highly recommend using carbon fiber composite props. There are some available from Europe that the speed-trail guys use which may be of a size you will with to try. Other than that, you have to design and mold your own.

Bob
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Old 08-31-2006, 12:58 PM
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Default RE: Need 9.5X8 or 10X8 Prop 30K RPM


ORIGINAL: bob27s

That sounds a lot under-propped....

For prop-jet use I'd probably lug that engine down closer to 18-20K rpm ground peak. It all depends on your pipe length and prop selection.

Any of the APC D-1 series props would likely fit the bill....

8.8x8.5 8.8x8.75 8.8x9 8.75x8W 8.75x9W are worth trying.

For a bit bigger blade, try LP09580 9.5X8N


However, a word of caution. All of these props regularly turn over 20K rpm in flight on the Q-500 engines. I believe that 23000-25000 is probably not a huge problem.

Most definately do NOT spin any of the APC C-1 or C-2 series 9" or 10" props anything close to 20K rpm !!! However, with great caution

In the past, some folks have utilized the 11 and 12" props, clipped in diameter. At least this way the prop hub is much larger. Approach this method with extreme caution.

However if you seek to go anything much over 20000, I highly recommend using carbon fiber composite props. There are some available from Europe that the speed-trail guys use which may be of a size you will with to try. Other than that, you have to design and mold your own.

Bob
Thank's, yes sounds like it needs more prop it snaps to 25K instantly[X(], I have allmost all the D1 sizes they make, I will order a LP09580 9.5X8N if it's a D1 , I didn't know APC made that size, I think I need around 9.5 to 10 inch prop since the wing is 60 inch, I can shorten the wing 8 inches without touching the ailerons, I may clip it later after some test flights, I will try the APC and if it's in the ballpark I will order a couple Carbon props with a little more pitch since the dive speed and higher nitro may push the D1 props well beyond the safe zone. I don't want to overprop the 77 because I want to put my OS65VRDF in and compare performance since it's a direct bolt in.
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