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04-09-2007, 06:40 PM
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Join Date: Jan 2005
Location: Kamloops, BC, Canada
Posts: 163
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RV-8 with no flaps??
In the spirit of experimental aircraft has anyone built an RV-8 without functioning flaps?
I?m thinking in terms of a racer: The flap sections would be flush riveted under the main skins and onto the rear spars. Less weight, less mechanical parts, no gaps to catch air. Possibly designed with a slight negative inclination to promote higher cruise speeds.
Thoughts. . .
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04-09-2007, 06:56 PM
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Join Date: Mar 2006
Location: Sandpoint, Idaho
Posts: 487
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Quote:
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Originally Posted by kevinsky18
In the spirit of experimental aircraft has anyone built an RV-8 without functioning flaps?.... Possibly designed with a slight negative inclination to promote higher cruise speeds.
Thoughts. . .
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I'm pretty sure that Bruce Bohannon's Fly'n Tiger doesn't have flaps. I think he was just going for simplicity... not that he needs them. His strip is 2200 and he's stopped well before mid-field without using brakes. It's disgusting.
I would be careful with the reflexed flaps. My understanding is that there are only a couple of airfoils that are helped by reflexing flaps. I don't think the RV's airfoil is one of them.
Karl
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RV-8 #80240 SOLD
1999 BMW R1100RS
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04-09-2007, 07:29 PM
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Join Date: Jun 2006
Location: Castaic, CA
Posts: 549
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Dont some Maules have provisions to put in a few degrees of negative flaps to improve cruise speed? Whos going to try that on their RV 
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Mike Sumner
Castaic, Ca
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04-10-2007, 07:56 AM
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Join Date: Jan 2005
Location: Kamloops, BC, Canada
Posts: 163
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Yes the new M7 maules have a negative setting for flaps to improve cruise speed.
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04-10-2007, 08:06 AM
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Join Date: Feb 2006
Location: Pagosa Springs, CO
Posts: 130
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I tried reflexing the flaps during my early flight testing...I found the best speed was when the flaps followed the contour of the wing template (i.e. no reflex at all).
If you want to experiment, how about just cutting off the outside bay of the wings, like Harmon did to the -4 when he made it into a rocket? Just leave enough flange to attach the wing tips again (of course you will have to move the outside aileron hinge in one bay and cut the airleron down too.
There is a long tradition of clip-wing racers going back to the '20s at least.
John
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04-10-2007, 08:30 AM
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Join Date: Jan 2005
Location: Kamloops, BC, Canada
Posts: 163
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Clipping wings would be a bit more than what I would be willing to do at this moment.
I may consider the no flap option with a neutral setting.
The no flap option has the potential to add a bit of extra speed, a bit of extra climb, reduce weight and increase useful load. With the only penalty being a slightly higher approach and landing speed and of course no flaps for soft or short field maneuvers. But I think the RV-8 with close to 200hp isn?t going to have much of an issue with short fields and or even soft for that matter.
Handling characteristics for a no flap build would be very predictable as they would mimic all the published and proven numbers with zero flap settings.
Clipping wings on the other hand is a much bigger step into the unknown. It may provide a distinct increase in cruise speed but the costs would be higher. It would reduce weight but it would also reduce lift and thus cancel out useful load gains. All your proven speeds would now be out the window. And instead of reducing fabrication and simplifying the build it would increase fabrication and make the build more complex as all the control links ect would have to be modified.
I think the no flap option is an interesting option worth further investigation.
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04-10-2007, 08:48 AM
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Join Date: Nov 2006
Location: maple grove,mn
Posts: 244
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no flap take off and landing
a no flap landing at gross wieght could be scary
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04-10-2007, 11:06 AM
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Join Date: Jan 2005
Location: Kamloops, BC, Canada
Posts: 163
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Well I'm sure there has been more than one or two landings at gross weight with no flaps in an RV-8. In fact if I had flaps I would still at least practice all maneuvers without flaps on a semi regular basis as a matter of prudence.
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04-10-2007, 11:36 AM
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Join Date: Jan 2005
Location: SoCal
Posts: 2,061
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The flap attach hinge and upper fairing is about the cleanest on the aircraft so it's hard to imagine getting any real speed gain here and you definitely make the plane more difficult to land. As far as reducing complexity, it's next to nothing. I just can't see the point in it.
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Steve Zicree
Fullerton, Ca. w/beautiful 2.5 year old son 
RV-4 99% built  and sold 
Rag and tube project well under way
paid =VAF= dues through June 2013
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04-10-2007, 11:38 AM
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Join Date: Mar 2005
Location: ...
Posts: 2,049
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And good luck selling that airplane. Not that you wouldn't find a buyer, but imho you'd be limiting your market.
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Dan Checkoway RV-7
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