Horner Wing Tips

[jiott]

I ordered the Horner style wingtip upgrade, but haven't put them on yet and am having second thoughts. They are a lot longer than the standard ones and seem more vulnerable to getting damaged.

Does anyone have any opinions on how much better they really are and what are their real advantages? They obviously extend the wingspan and so would reduce stall speed, but how much? Do they also reduce cruise speed (more drag)? Would they make the plane more unstable in turbulence? Do very many of you have this option? Pros and cons.

Thanks,
Jim

[chefwarthog]

Very interesting Question you have, I was looking ahead to intall those on my futur plane so, will follow in any reply.

[HighWing]

Jim,

I doubt you will find many with before and after experience. From what I have heard over the years, there is not much difference performance wise. The droop tips are a bit more forgiving in ground loops as they can act as an outrigger. Lots of folks have scuffed them, and then trimmed the opposing tip to match and flew on. I have flown in numerouis group flights with guys with the droop tips and with the Horners and no particular person comes to mind as being the slow guy. I bought the option back in the day because I liked the look better.

With my first build, I was trying initially to fit it in my garage and trimmed the wing tips substantially to reduce their impact on overall folded length. It was pretty easy to do, but I found that I had to use a sanding flapper wheel to thin out the lower skin so it would take a shorter radius turn to mate up with the lower rib capstrip. After I thinned down to about one bid to allow the bend tight enough to fit, I layed up a couple of layers of glass on the inside in the thin area and then fastened it to the wing and it cured in the new position - didn't have to touch the outside. The nearest I can determine is that it was just short of 8-1/2" edge to wing rib.

If you do decide to go with the Horners, I can give a tip I did on the current project. You will likely trim a bit off the inboard edge to fit the tips. Save the material and when you are ready to glue up the trailing edge. Take some of the scrap, cut two pieces about a half inch wide and the length of the glue joint on the trailing edge. Scuff everything and Hysol the four layer sandwich and clamp with with a couple of pieces of angle extending off the trailing edge. Clamp everything up nice and tight and you will get a trailing edge the same thickness as the aluminum edge, straight as a string and the laminate will give enough stiffness that it will stay straight. A little micro will fair in the rough spots on the edge.

Lowell

[jiott]

I was hoping for a few more opinions on this to help me make up my mind.
Thanks Lowell for your response.

Jim

[t j]

My opinion is the Horner style wing tips look much better than the shorties. I would install them. If you decide later you don't like them for some reason you can probably trade someone.

[Dorsal]

As stated above there are probably not many who have used both and I suspect the differences are not large. I have the Hoerner style, I like them but not really based on anything. I also used the scrap technique as mentioned by HighWing, works well. One more thing I did was to build out my own mounts for lights which I felt was a bit cleaner than the supplied mounts.

[jtpitkin06]

Hey if it’s an opinion you want… here goes!

Hoerner wing tips


[Note: Dr. Sighard Hoerner frequently has his name misspelled as “Horner”.]

If Hoerner tips were the answer to everything aerodynamic; then, that’s all you would see installed on every aircraft. Yet, you see many different tips on wings. Certainly the manufacturers could make a Hoerner tip for the same price as a rounded tip. Hoerner tips have been around for over 60 years. So what’s up?

If you install Hoerner tips, you may see some improvement; or, you may see some degradation in performance. How you terminate the wing does make a difference. Only a flight test will tell you if the difference is what you wanted. I seriously doubt anyone put the Kitfox Hoerner tip or any other tip in a wind tunnel and did any comparative testing. I would simply call all the available wing tips “style fairings” with no expectation of aerodynamic improvement.

Now, if someone has flown a Kitfox with both sets of wingtips and has definitive flight test data, we’d like to hear from them.

Many people incorrectly identify a drooped wing tip as a Hoerner wing tip. A true Hoerner tip does not droop downward, The bottom surface of the wing is blended and sloped up at approximately 45 degrees to a sharp junction of the upper surface.

Styling has a lot to do with wing tip design. For a while there were only rounded tips, then Hoerner tips sloping up, then droop tips sloping down, and winglets projecting upward. There is also the Airbus solution… put two winglets on the tip and go both up and down!!!

Many times the results are surprising. Recently an owner of a KR-2 installed new tips. He extended his wing span almost two feet to lower the stall speed and improve low speed handling. He expected the aircraft to be a bit slower in cruise. The extension did lower his stall speed and to his surprise the cruise speed went up, too.

If you are looking for “style”, then put on whatever you think has the look you like. If you are looking for performance and lower stall, then you are in for a long series of flight tests and several different tips and each tip rigged at different angles.

John Pitkin
Greenville, TX

[Dorsal]

Well stated

[desertfox1]

The Factory tested both tips on the same plane. I wasn't
there so it is only third party reporting. I was told by the
pilot doing the tests that both tips were an improvement
over a flat covered end rib. However, without a boom for
accurate speed measurement the difference between the
two tips couldn't be measured. So..deciding which tip to
use probably is what looks best to you. The "Hoerner" tip
adds span, wing area and weight. Looks great on the
Speedster wing. I recently completed a short wing 'Fox
with the new tips and had to trim a couple inches off the
flaperons to make it look right. Ah well, Experimental.

Phil

[jiott]

Thanks,
This is the kind of thing I was looking for.

Jim