Article of Interest

[schrome]

www.eaa.org/experimenter/articles/2011-10_sonerai.asp



Ed

[oahupilot]

error 404 the link appears to be dead

[schrome]

Try this...

www.eaa.org/experimenter/articles/default.asp

...then look for "Roger Godfrey's Sonerai IIL" about 20 bullets down.

[wbpace]

It is certainly an interesting article. If I understood it correctly, he extended the wing span by 4 feet. Yeah, that would likely improve rate-of-climb, but I would expect it to also increase drag (and thus reduce max airspeed). I wonder if the chord was reduced at all to reduce wing loading. I'd love to see a follow-up article comparing the performance of the two wings.

[schrome]

I believe Ivan uses a Riblett airfoil. Maybe he could give us a before/after comparison?

[peterzabriskie]

Hi folks, Roger is a great guy and we talked at length the last two Airventures I made it to. We still email a little. He told me if he did it over again he would not lengthen the wings. He was striving for a Sonerai that would carry two people with decent rate of climb. The Riblett 35A415 airfoil he uses is two inches thicker at the spar and that alone is enough to get the performance he was looking for. He said he does sacrifice a little cruise speed but it is not appreciable and he is not going anywhere in a hurry anyway. He also did lot's of neat little things like a fairing for his tailwheel to clean up the drag.
-Pete

[hans]

Did Riblett also do a 35A412 airfoil ? I've read mixed reactions about Riblett's work; is his catalog worth the purchase?

cheers
Hans


EDIT: apparently he did, trying to find more data now...

[godfrey]

Hi Guys,
I wrote the original article for "Contact" magazine and it was reprinted in the "Experimenter" with a few additions. I can perhaps react to a few of the comments I have seen about the article. Making the wings longer with the original airfoil does not improve climb or lifting ability of the Sonerai II. A friend here in Iowa built three sets of wings for his Sonerai II. First he built the standard wing with the original airfoil. He thought the performance was poor with some of his friends in with him. Perhaps he had big friends I never met them. He built the second set of wings adding two feet to the length of each wing and used the original airfoil. He said the plane was slower and did not climb any better or land any slower. He said unkind things about the original airfoil. Then he built a third set of wings with a Ribblet airfoil, kept most of his original speed, got a much better take off, climb and landing performance. Talking to him led to my building a Ribblet wing. One fellow commented he had heard different things about Ribblet airfoils. I'm not surprised, Ribblet did lots of research on airfoils most of which came out of the 1930's. His research is solid and his book is excellent. On the other hand I have heard he is not shy about telling designers that they have used entirely the wrong airfoil on their design. Someone told me John hates him, probably the recipient of some unwanted advise. The question I get the most often is on speed of one wing verses the other, I can't really answer that with any degree of accuracy. I made too many other changes at the same time I replaced the wing. I added wing root fairings. gear leg fairings, brake fairings, a tail wheel fairing, horner wing tips, and nine inches to the vertical stabilizer and rudder. I also went to a 2180VW from an 1834. The prop hub on the 2180 was longer so the new nose is a little more streamlined.
Roger Godfrey

[schrome]

...and the airplane really looks good too. Congratulations, Roger!

Ed