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Ribblet Airfoils

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Schmleff

Well-Known Member
Joined
Jan 2, 2006
Messages
2,714
Location
Waupaca, WI / USA
I know that some of you have Ribblet airfoils on your Sonerai. The SII project I have has a Ribblet airfoil built for it. In my paperwork, it seems that the builder had worked with Harry Ribblet directly to come up with the correct airfoil for the plane.

My question is this. Have you other Ribblet guys spoken directly to Harry?
 
Yes I have spoken to Harry many times over the phone & several times at Oshkosh in person. If you call him he will answer any of your questions.
Which airfoil does your plane have? My plane has a Ribblett airfoil Ga37 415 if I remember correctly. My plane will not stall or drop a wing with power off & stick pulled all the way back...just a mush under 60MPH. From the speed of my plane compared to other Sonera2, there must have been very little speed lost (as Harry said it would be)

Ivan in Sugar Land, Texas.
 
Unfortunately, I am not comfortable with the way these wings were built (or designed, its how the spar is set up) and have a set of standard sonerai wings that will go on it.

I asked about Harry since I want to talk to him about an airfoil for another project I am working on.
 
Ivan I talked to Roger about his Riblett wings and he said that the spar was built up similar to the normal Sonerai spar but wider/with wider sparbox and that wings the same length as Sonerai wings would gve the desired results in lift. Did your wing construction work along the same lines as Sonerai wing construction, with the exception of the shape of the ribs and spar width?
-Pete
 
yes, the wings are built like a standard sonerai wing, but the airfoil is thicker and he tapered the spar to fit a standard sonerai spar box. I will snap a few picts when I get home and post them.
 
My wings are 1-1/2 thicker than the standard wings. My spar box is also 1-1/2" thicker than the standard spar box. I moved the main spar back 2" which is the same as moving the wing forward 2" I had an engineer look & approve my wing modifications cost $400.00) Moving the spar back is not good but the extra wing thickness nullified the problem. I had to also lower the spar box 3/4" My calves barely clear the top of the spars. If I had to do it all over again I would have chosen the Ga37 312 which is the same thickness as the Sonerai airfoil. The Ga37 312 is the equivalent of the Sonerai airfoil but with the nose cuff for milder stall.

Ivan in Sugar Land, Texas
 
lqbanotxano said:
The Ga37 312 is the equivalent of the Sonerai airfoil but with the nose cuff for milder stall.

This could imply that the stock airfoil may have a not-so-mild stall. Just so that newcomers to the site don't get the wrong impression, my Sonerai with its standard airfoil stalls straight and predictably at 48 mph. I consider its stall behavior to be rather mild.

-Scott
 
Pete

Everybody that I have spoken to that is flying says that the standard Sonerai airfoil is fine. I am a tinkerer & like to come up with different solutions to the same problems. Example...for the past few months I have been working on a new cowling. The cowling will be a "holy cowl" in 4 pieces, with 11 degree diffusers, snorkel air intake, snorkel oil cooler intake, box baffling, prop extension. Sure it will be neat to have a "holy cowl" Sonerai like the fast RV8's, Harmon Rockets & Lancair. But...look at all the flying time I have lost.....every weekend for the past 4 months.

Stick to the plans or you will never finish.

Ivan in Sugar Land, Texas
 
Copy that. I was just intrigued by the performance that Roger got out his Riblett wing. Carrying two 200 lbs people and maintaining good climb and landing characteristics. I will be flying solo exclusively so the point is mute for my construction. It is interesting though what the shape of the wing can do for performance though. "Holy cowl" yea...that sound like more work than I want to get into...like the rear drive engine...and the aux fuel tank...etc... ;) Cheers, Pete
 
Not to mention the fact that two 200 pounders should be good friends in a Sonerai. It is quite cozy and you may be touched in places your not quite used too. :D

Tim
 
Apart from Ribblet Foils, what other airfoils have been tried on Sonerai aircraft?
 
Has anyone tried out NACA 23012 on a Sonerai. It has unique characteristics suitable for the everyday home builder and performance on par with the 64(A)212
 
N127PZ said:
I was just intrigued by the performance that Roger got out his Riblett wing. Carrying two 200 lbs people and maintaining good climb and landing characteristics. I will be flying solo exclusively so the point is mute for my construction. It is interesting though what the shape of the wing can do for performance though...

Count me among the guileless neophytes, albeit a geriatric one, who remain fascinated by the Riblett airfoil approach. Mike Shuck (on his yahoo-airfoil site) has probably done as much independent analysis of these airfoils as anyone. It goes without saying that Harry was probably the most vocal advocate of his own motif, not to mention a bit of a thorn in the side when it came to standard NACA airfoils whether turbulent or laminar (and more than once he expressed his dislike of the 23012 and progeny). At least with Harry, one could actually chat with him – I met him once briefly, and called him several times on projects of mine (that I never completed). Even when he was clearly sliding downhill fast, he still found time to come to the phone – he seemed to love chatting about wings and foils.

Harry’s general mantra was what he called soft-stall, low trim-drag foils while retaining rather sizeable CLs. There clearly have been enough birds flying with his work to be confident that they are not quirky, indeed reputedly just the opposite – he used a rather rigidly defined nose portion around the camber meanline (I think almost all of his that he published used the 0.5) as verses the vector-radius method which the NACA foils use – NACA having settled on this method back in the 1930s. I’m thinking the 37GA utility laminar series is quite intriguing, and depending on CL actually projected, either the 31X or the 41X so the bucket stays in the usable range. In any case, whether one agrees with Harry’s motif or not, his booklets on foil design (still quite widely available) over the years are very understandable and have done much to take Abbott and Doenhoff and make their empirical evaluations and theoretical calculations understandable by mere mortals.
 
N127PZ said:
Ivan I talked to Roger about his Riblett wings and he said that the spar was built up similar to the normal Sonerai spar but wider/with wider sparbox and that wings the same length as Sonerai wings would gve the desired results in lift. Did your wing construction work along the same lines as Sonerai wing construction, with the exception of the shape of the ribs and spar width?
-Pete

Pete:

Hi, I realize this is a very old post, but I am very interested in the Riblett airfoil for a Sonerai project. I currently have Sonerai II N610BS and it's great, but I want to work another Sonerai IIL as a project.

I'm hoping to find drawings, photos and other tech data on this wing's build and installation on a Sonerai. Any N-number leads on the few Sonerais with this wing would be great, especially if any of them, or any Riblett Sonerai wings are for sale.

Thanks,

Wally
 
Thanks for the great info and links on the Riblett Sonerai wing, I really appreciate you finding that for me!

Blue Skies,

Wally
 
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