kevinsky18

kevinsky18

Well Known Member
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. . .
 
kevinsky18 said:
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. . .
Click to expand...

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. :cool:

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
 
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 :)
 
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
 
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.
 
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.
 
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.
 
And good luck selling that airplane. Not that you wouldn't find a buyer, but imho you'd be limiting your market.
 
Don't

Kevin,
I teach no flap landings to all the guys that come here for Transition training in case theirs don't work, as mine have done a time or two. To a man, they're amazed at the flare and flare and flare without flaps......a really long time to burn off airspeed. My other concern would be your inability to add/remove flaps in an emergency landing, in order to vary your glidepath. Slips aren't as good as flaps and your impact forces will be significantly higher at no-flap landing speeds.

My .02,
 
I'm afraid that I have to agree with Steve on this. I can see very little, if any, positives and several negatives.
 
I generally do flapless landings on my -6A and the aircraft has much better manners like this, although vis in the flare is reduced a bit.

Darryl Greenameyer's race winning Legacy has no flaps. One hot ship to land though.

The CT Design aircraft have a substantial reflex flap position available for cruise but use a very different airfoil.

It would be an interesting experiment but unlikely to add many knots or reduce weight much. Certainly though, RVs don't need flaps to land or take off from even medium length runways- say 1500 feet.

I'm always amazed that most RV pilots dump full flap for every landing. No wonder some seem to have so many problems with flap motors.
 
Ross,
I think there is another situation going on with many people with motor burn ups on the flaps. They put full flaps on too early in the game and the airspeed is too high. On another post it was talked about using manual flaps, it caught me that it is really hard to put on manual flaps at too high of airspeed. Dah! that electric motor is having to overcome all the forces to put on the flaps. I agree, most people have to put full flaps on, may not be a good idea in all situations, and the timing for putting on full flaps???
 
Steve,
You bring up a very good point. Since I live on a short strip, I generally use full flaps, but I don't put in the last notch until on short final (about 75 mph). On another note, I have found that the last notch (last 10 degrees) don't lower stall speed. They just add drag.
 
Nuisance said:
...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... John
Click to expand...

I'm pretty sure there's more to it than cutting metal at the end of the wing. I think the ribs are re-spaced in a Harmon Rocket. That would be very hard to do with a pre-punched or match-drilled RV-8. Not worth it IMO.

Karl
 
makes me feel good

;)
rv6ejguy said:
I'm always amazed that most RV pilots dump full flap for every landing. No wonder some seem to have so many problems with flap motors.
Click to expand...

I most of the time put full flaps on any landing.
It saves tires....At lower speeds, I have better control over the aircraft...If something goes wrong, the lower speeds helps me to survive....lower nose helps me see the approach better.......gets me off the active faster.....have more runway to play with...I can grease my landings better.....saves my gear legs....and this all makes me feel goooood :D
 
szicree said:
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.
Click to expand...
Good point Steve.

Why not get someone with an -8 to tape up any gaps and do some before and after test flights for you?
 
You must log in or register to reply here.