Wing Tip Shape Summary

Dave Calkins said:

a couple of photos

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A fan of aircraft design on this end for eons including wingtip design. I can't wait to hear performance numbers aka what type of improvement on the top on bottom end. This particular shape I have been doodling for over a year (with other components as well), and trying to figure out how to do in Solidworks, it maybe trickier than it looks, but let that go. This shape dovetails in a way off of the "Elipse Tips" the L-39 racers are using and the later RV-Tips that went from Hoerner to this 1/4 Ellipse style of which there is some data on the web, but it is hard to find.

If you read Harry Riblett's book and look at the Sullivan & Metcoair tips the trailing edge of those tip and Harry's recommendation is trailing edge of the tip be colinear with the wings trailing edge. This tip does that and if I see it correct, it takes the existing 40's trainer bow type tip ( of which we know now may not be the best ) and extends the tip back and make the trailing edge colinear. If this works, how is this not a slam dunk modification/potential STC and or 337 for a host of 40's (and later) fabric favorites?

Reading on aero design especially at the tip and if you look at what Steve Wittman did with his W-10 tip, you get a sense the last 20% or so the vorticies are trying to go span wise, rap up and over and head towards the tip and generally be a pain. Thinking out loud, but by putting area outboard of the aileron to allow this to happen and keep the ailerons happy and delay all the calamity by the trailing edge being all the way aft and perhaps putting the vorticies to work maybe a good thing. The 2 SW-Piper STC's and what the Seabee guys did via their extensions outboard of the ailerons make a heck of a lot of sense if what I am thinking actually is valid.

Tangent subject matter is what Al Bowers and the Prandtl Wing does with that last 20% or so the dramatic twist they use, but that is way off topic, other than the 20%....

My best,
Anthony

Anthony. I agree with you in all points.

This would likely be a drag-reducing tip. But is it a lift-adding tip?

I will add that any droop tip will trap high pressure air on the undersurface better than a “co-linear tip, in my estimation, and in testing done by others’. If those droop tips increase span, so much the better, for slow flight.

This tip style on this airplane provided a cruise speed of 110 mph, as related to me by the previous owner. What prop pitch, what power setting. what accuracy of ASI and tachometer?????? Those are the questions.

I will not have before and after numbers that will be relavent, but I will have an idea if these are horrible, or acceptable.

My hopes for this -14, and for any Cub I build, are for decent slow speed performance.

Thanks for your input. d

Dave it may be interesting to play with washout and those tips. The wing is changed versus stock and should retain air underneath differently as well. Speed at each end of the range, roll and yaw rate vs aileron deflection, slow flight and stall behavior. Are there or will there be VG's? Hopefully not at first until something's learned about the bare wing as-is. Then a comparison versus stock wings if possible from experience or another -14 if there's still one around that's normal.

I read years ago somewhere that the length of the training edge (and ultimately the effect upon aspect ratio) was important for lift and drag. Then tips get added and their design (airfoil or not) becomes a confusing part of all that. This may be a great opportunity to learn.

Gary

I love the Plane Boosters, the name is spot on. I have no doubt they alone can reduce Vx airspeed by 15%, probably 20%. Sometimes I think I like the stock bow tip look better, but the performance gain with the Plane Boosters droop tip is, super plane boosting, gets you off the ground sooner and climbing steeper.

Manufacturers should install and promote the best wing design with new sales. Do they?

Gary

Misspelled it, Booster not Boosters. I just gave a educated guess on % increase in performance, never actually recorded numbers, but google found this old brochure from 50 years ago, it has some data, interesting. Click the two links to download whole pdf brochure
https://www.shortwingpipers.org/forum/attachment.php?attachmentid=13234&d=1522343617
https://www.shortwingpipers.org/forum/attachment.php?attachmentid=13235&d=1522343747

Erickson at dakota cub must have done some wing tip theory, hes sortve sticking to his version of what works.

Just purchased a Wag Aero Sport Trainer and it has, what I believe are Madras wing tips. Never seen them b4.
Can anyone provide info on them. I'm new to the tail dragger seen, and trying to get myself up to speed.
Thanks.

Not quite dead on topic, but...
cam someone post some photos of the tips that come with the Sportsman STOL cuff for C180/185?

hotrod180 said:

Not quite dead on topic, but...
cam someone post some photos of the tips that come with the Sportsman STOL cuff for C180/185?

Click to expand...

https://www.steneaviation.com/products/sportsman-stol-late-kit

Oh, ive checked out stenes website.
Just didnt see any photos where i could really check out the look of the wingtips.

hotrod180 said:

Oh, ive checked out stenes website.
Just didnt see any photos where i could really check out the look of the wingtips.

Click to expand...

We just modified existing tips to fit cuff, or stop cuff before tip and use a plate


Sent from my iPhone using SuperCub.Org mobile app

hotrod180 said:

Oh, ive checked out stenes website.
Just didnt see any photos where i could really check out the look of the wingtips.

Click to expand...

Look here under Sportsman: http://www.aerofairings.ca/parts.htm They are flatter and wider at the rear than Cessna's. Add some wing span. I flew them and never crashed.

Gary

this

mike mcs repair said:

We just modified existing tips to fit cuff, or stop cuff before tip and use a plate

Click to expand...

I really like the look of the stock Cessna tips,
if I was to get a Sportsman cuff I might consider the plate approach.
Not sure I'd like the look of that either though.

If yu want to improve aileron authority and also high AOA flight regime safety, put a Sportsman STOL on your 180.

I think it is the best cuff. Am not sure VG’s are necessary with the Sportsman performance increase.

BC12D-4-85 said:

Wasn't this PA-14 recently for sale with the note the tips had to be removed for some reason? It used to be at Bradley's I believe and I recall seeing it. The idea of the tip design was the length of the wing's rear determined the best lift, something like the Britten-Norman Islander's tips but not upturned just flat.

Gary

Click to expand...

the islander had 2 different wingtips as shown in this line drawing the bigger tips added 4'? and extra fuel

Hi Bugs do you have any pics or details on fitting these tips.

Dave Calkins said:

If yu want to improve aileron authority and also high AOA flight regime safety, put a Sportsman STOL on your 180.

I think it is the best cuff. Am not sure VG’s are necessary with the Sportsman performance increase.

Click to expand...

Agreed on both counts.

MTV

BC12D-4-85 said:

Look here under Sportsman: http://www.aerofairings.ca/parts.htm They are flatter and wider at the rear than Cessna's. Add some wing span. I flew them and never crashed.

Gary

Click to expand...

Its not rocket science. Lots of conversions been done....

I talked to Atlee Dodge a few times over the years. I was mostly asking about flaps and the fit on the body of a PA-12. We got to talking about wing tips. I am a fan of the original Piper wood bow. He liked a squared wing with a flat plate. He said they did some testing and it was more about wing area then tip shape.

On a side note I fly and maintain a couple of glider tug Pawnees. One has a field approved squared wing with a flat plate fiberglass tip. It’s the more popular of the two. The pilots say it just flys nice. The other one has squared wings with Madras tips.

Charlie Longley said:

On a side note I fly and maintain a couple of glider tug Pawnees. One has a field approved squared wing with a flat plate fiberglass tip. .

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Mr. Longley;

Would it be possible for you to post a photo of that wingtip setup please? I'm in the early stages of building and this sounds like what I had been thinking of for my tips. I'd sure like to see other examples. And for the general list membership, well photos of planes are never a bad thing. No worries if you can't or don't wnat to bother, but I'd be interested. Thank you.

RedOwlAirfield said:

Mr. Longley;

Would it be possible for you to post a photo of that wingtip setup please? I'm in the early stages of building and this sounds like what I had been thinking of for my tips. I'd sure like to see other examples. And for the general list membership, well photos of planes are never a bad thing. No worries if you can't or don't wnat to bother, but I'd be interested. Thank you.

Click to expand...

Yep no problem. Here’s a couple of pics from when it was hit by a golf cart and I repaired it-




Here’s a couple of random pics I’ve taken over the years-

The guy that owns Golden Wings Aviation did the mod and still has the molds.
https://www.google.com/search?q=golden wings aviation

Charlie Longley said:

The guy that owns Golden Wings Aviation did the mod and still has the molds.

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Thanks Mr. Longley;

Looks pretty similar to what I had in mind. I'll check in with him and see; might just be cheaper to use his option than to build my own.

I'll keep y'all in the loop

ROA

That's a nice way to end the squared off wing.

Gary