S 2 clipped wing...

[jeff naul]

What I've been wondering is if I clipped the wing of a sonerai 2 and then add a Hoerner wingtip. Would that give the speed of a clipped wing without losing any of the stability of the long wing? I'm sure this has been discussed but my searching came up with nothing.

 

[smokyray]

Jeff, in similar fashion, the Harmon Rocket is a derivative of the RV4 with shorter wings. You build the wings with 2 less rib bays shortening the span by almost 2ft which effectively increases the wing loading. You also lengthen the fuselage and use thicker metal for strength and literally double the horsepower up front! Many builders opt for the "bat-plane" wingtips afterward, shown below.
Doing this to a S2 might be similar. I removed my Hoener wingtips from my RV4, installed a flat plug in the end of the wingtip and put a small fence on the bottom of the wing at the tip. Performance was virtually unchanged but roll rate increased as well as fit inside the hangar...FYI.
V/R
Smokey

 

[jeff naul]

Thx, Smokey.... I'm kind of spit balling ideas right now.. I'm about to start working on mine again. It's a flying airframe so I have to be able to do it relatively simple. What started it is my tips look like crap. I'm going for all the speed I can get this time around. I was thinking clipping the wing a foot on each side with hoerner tips to keep the stall close to the same. I may hear that a foot off isn't enough to gain much speed. Surely somebody has done it lol...

 

[Chucker]

Smokey,

Pictures of your "small fence?"

Chucker

 

[jeff naul]

The more I have read today I don't think I'll see any gain worth going through all of this work. I think smokeys RV 4 was a good test.. has any of the guys who built hoerner tips on sonerai ever reported any numbers after?

 

[Chucker]

I bought my project with one wingtip already installed. I have played with the idea of simple square tips.

Chucker

 

[oahupilot]

If you go to my gallery or dig through the post, some time ago I posted the CFD analysis of the hoerner tips on a sonerai wing.

 

[Raceair]

Jeff Lange has retro-fitted slick Hoerner tips to his Sonerai, even produced a video on how to do so, and reports that it is way better, he can feel the difference in the way it lands too...He' is at Reno at the moment, but maybe will comment when he gets back

 

[smokyray]

Smokey,

Pictures of your "small fence?"

Chucker

Chucker, I don't have any pictures (I can find, or remember) :-\
However, I first tested the design on my Ugly Stick RC model. I basically extended the chord line from the bottom of the rib to the trailing edge. The height of the fence was set so the wing sat at zero incidence sitting flat on a table after installation. The fence is positioned at the outermost lower wingtip area, outside the aileron end gap. I basically employed "droop wingtip aerodynamics" without adding wingspan.
I fabricated the fence from .040 6061 T4 stock.
Here is a photo of a Wren 460 with a tip fence/hinge fairing very similar to the one on my RV4...
http://www.acmp.com/blog/wren-460-the-ultimate-stol.html
V/R
Smokey

 

[mhflyit]

Joe Curtis was looking into something like this for his S1.

 

[jeff naul]

Ed, I guess the drag boat racer in me wants to hear actual before and after results...not that it feels better... lol... believe me that sounds like I'm being a smart ass but trust me I'm not. I've watched Jeff's video several times taking notes. I don't have good enough data from when I was flying my sonerai to be able to do it now and report back with results to the group... if no one has any good data then I'll just have to wait and try them after I'm flying again.
what are your thoughts on building the counterbalance into the wing and not out in the airflow? Thx, Jeff

 

[Raceair]

I know a couple of the FV guys put the counterbalance into the wing, but I don't know the mechanics of how to get the balance tube into the wing without cutting a large hole in the rear spar shear web. Perhaps it goes out into the tip outboard of the rear spar.

 

[jeff naul]

Ed, my thinking was at the tip and the wing tips cover it. If there is enough room. Awfully thin wing.
So I've been looking at alot of planes with thin laminar flow wings. Pipers mainly. Saratoga, Malibu because there are 2 in my hangar. They have flat flush caps for tips.. so that makes me wonder if a thin laminar flow wing benefits as much from a Hoerner tip V/S say a thicker Cessna wing. My buddy's 152 picked up at least 5mph he said when he put them on. My Zodiac has them... again, big thick wing. Jeff

 

[Schmleff]

Before and after data was not available for mine since I did too many other things at one time. It does land differently than it did with rounded tips. It does not just quit flying like the old tips did.

FWIW, at 970 lbs with full fuel, bags and my fat butt it still out climbs a twin Comanche on a 100 degree day ; )