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Old 02-13-2008, 10:42 AM
pierre smith's Avatar
pierre smith pierre smith is offline
Join Date: Jan 2005
Location: Louisville, Ga
Posts: 7,806
Default Hi Dave..

....thanks for coming here. I added gap seals to a Cassutt racer and picked up quite a bit and I've read that you added them to the -4. If so, what effect did it have on the controls and did you see a significant gain?

Pierre Smith
RV-10, 510 TT
RV6A (Sojourner) 180 HP, Catto 3 Bl (502Hrs), gone...and already missed
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Air Tractor 402 PT-6-20
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Old 02-13-2008, 11:11 AM
Christopher Murphy Christopher Murphy is offline
Join Date: Feb 2007
Location: colorado
Posts: 758
Default high speeds on airframe

Hello Dave,
Your RV-4 is a beauty. I know everyone wants to make their plane faster. What have you done to the airframe that allows you to go that fast( past redline) without concerns of flutter or structure failure? I noticed you use the flat wing root fairings with the rubber grommet. Have you tested the contoured root fairings and if so what difference did you find?

Chris Murphy RV-4
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Old 02-14-2008, 05:58 AM
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rvator51 rvator51 is offline
Join Date: Jan 2005
Location: Peoria, AZ
Posts: 999

Hi Dave,
Wondered if you could comment on your muffler system and what components you used and what effect the muffler system has on your speed?

Thomas Velvick
Goodyear, AZ (KGYR)

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Old 02-19-2008, 07:40 AM
dsb dsb is offline
Join Date: Feb 2008
Location: Dahlonega, GA
Posts: 22

Sorry if this question is naive...

But I was wondering how this increased speed/speed mods related to the stock aircraft's Vne... I read an article where an RV-4 pilot inadvertently induced some control flutter, and that was at a considerably lower speed than 260mph.

BTW, can someone point me to a source that states what the Vne actually is? I've read a few POH's that put it at ~210mph TAS, but I can't say that I've read where D.V. said what it is...

On a different note, any ideas of the drag reduction due to the raised turtle deck?

Very interesting stuff, I read the time line/modification article and am simply amazed...

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Old 02-19-2008, 12:11 PM
arffguy arffguy is offline
Join Date: Jan 2005
Location: Elk Grove, CA
Posts: 357
Default I wish I was as studious as Dave

Yes, the manual for the RV-4 says that VNE is 210. I think that Dave is extremely careful when going faster than that. One thing is that I think Van's is slightly conservative (probably with good reason) and that it is generally considered by some people that the RV is overbuilt. The only two people I have seen fly it are Dave and his wife while he was in the backseat. I don't know what speed he normally cruises at when alone but when flying with a group of "normal" RV's I am sure matches their speed. Keep in mind that this extra speed is most likely why he added a counterbalance weight to the rudder.

As far as the speed increse with the turtleback mod, he did that along with some other mods so was unable to determine an exact number, if I recall this correctly.

One other thing, a friend of mine who has ridden in the plane says that it gets quite warm in there, even with the tinted canopy, since the cabin air apparently comes through the engine compartment first.

P.S. Thanks Dave for offering to clear up some of the info sheet stuff. The stuff over my head more relates to the use of the mathmatical formulas and such. I didn't go to engineering school or anything like that
Mike F
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Old 02-19-2008, 03:54 PM
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dpansier dpansier is offline
Join Date: Jan 2006
Location: Green Bay, WI (GRB)
Posts: 360

Take a look at building tip #4 on the following link, it will answer some of the questions that have been posted.
D. Pansier
Green Bay, WI (GRB)

Antennas for Experimental Aircraft
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