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

OT/ Need aero help

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Old 05-05-2009, 01:36 PM
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asmithnc
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Default OT/ Need aero help

Hey guys.... as you can see below this is not an airplane but it wants to fly like one. At higher speeds it likes to lift the front sponsons and the large surface area is acting like a kite. I need your help with tring to slow the flow of air on the top deck so the nose won't lift. Or other suggestions would be nice.

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Old 05-05-2009, 01:42 PM
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Default RE: OT/ Need aero help


ORIGINAL: asmithnc

Hey guys.... as you can see below this is not an airplane but it wants to fly like one. At higher speeds it likes to lift the front sponsons and the large surface area is acting like a kite. I need your help with tring to slow the flow of air on the top deck so the nose won't lift. Or other suggestions would be nice.

Quick flip

Unless this is an unfinished version, I think you need to spoil the airflow, as right now you have a huge flate plate and no wonder it is lifting. What about experimenting with some triangle stock or some kind of fence on the leading edge of the deck? Is the deck at some kind of angle of attack at speed?

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Old 05-05-2009, 01:49 PM
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Default RE: OT/ Need aero help

Hi!
First you have the engine too far rearward! This makes the C of G critical at high speeds and the front lifts suddenly, making the whole thing flip over!
Second put a wing up front! Like on a Formula one car to get down force!
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Old 05-05-2009, 08:07 PM
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Default RE: OT/ Need aero help

Thanks for your input.
First I would like to say that this boat (kit) was never designed for this much power or speed. I guess that why I'm doing it.
Second the engine will go on another boat designed for higher speeds.
Since I can do nothing on the engine placement I need to look into aero. I'm a machinist and thought this problem would come up so I made spoilers. I forgot I had them until the F1 wing thingy came up (Go WEBER). Will they work or do I need to make something else.



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Old 05-06-2009, 09:40 AM
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Default RE: OT/ Need aero help

Hi!
Looks Ok to me! But see to that you make it (them) adjustable
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Old 05-06-2009, 11:20 AM
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ORIGINAL: jaka

Hi!
Looks Ok to me! But see to that you make it (them) adjustable
Thanks and yes I did think about it. LE add washer for higher degree and TE you can also add washer for more air flow.
After watching the video I did notice the angle of attack is bow high. I will also make add on rear sponsons to raise the bow to lower the attack on the bow. I'll just do one at a time to see what works.
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