Nobler, thin airfoil?

I have a set of a Nobler plans,

The airfoil, is it a NACA 18?

It looks kinda "thin"...

What if I use Larry's StuntRib and get me a set of NACA 20 foils?

Also, maybe a little more tail moment and, if I think it's needed, a litle more elevator area.

Am I insane "or do I really see heaven in your eyes"?...LOL

My idea is not have an OTS, but have a Nobler, but a little "spiced up"...

God bless you!

In Christ,

Ion,

Just get a set of the 68 Gieseke Nobler plans - they have all those modifications already done. If you want to change it into a modern plane, that's already been done too. That one is the "Bear"!

Jim beat me to it! LOL!!
Yep, Geiseke Nobler has the mods you are referring to.
Doug Moon (Ultra Hobbies) has the "original" plans of Bob's plane, IIRC.
Bill

I would presume that punching the airfoil up 2% would make the plane inelegeble for Classic. Unless, of course you can prove that one was built that way in the Classic era.

In this case, the Gieske Nobler fills the bill. But what about a "fat" Ringmaster, for example.

Ion

I think it would be fair to say that, whatever the thickness, the section is unlikely to be NACA 0018 or any others in that specific family.

On several occasions, George stated that he believed that the NACA 00xx series sections were too too thick at the front. Given that all the Nobler drawings that I had seen showed a curved rear section (behind the max thickness point), George's statement about thickness was what started me splicing other sections onto the front of NACA 00xx several years ago.

I have to confess, however, that I went off on other projects and have not checked the actual sections on Nobler drawings to see whether there is a close digital equivalent in the library.

I've got a Brodak Nobler. It ain't no NACA0018 - you can shave with the rotten thing. Turns like the dickens though.

If you're flying well enough to need to modify a Nobler (**raised eyebrow**), maybe you should be building something larger anyway.

I've got a Brodak Nobler wing complete, awaiting the fuselage and the airfoil is surprisingly thin to my eye. I remember building a green box Nobler kit in High School. I don't remember much about how it flew or how long it lasted--no doubt it was heavy--but it seemed there was more airfoil to it.

I have the ribs in the jig for a Tom Dixon kit of the '52 Nobler that has a thicker section. I'm not at all sure what the story is on this variant, although the opinion has been put forward that this is arguably OTS legit because this design (the Dixon kit of the Nobler) was already considered legal in a contest back East.

I hope to bring both of them in around the same weight and if I do it will be interesting to see which one is the better flier.

On one hand, I tend to think by just looking at it that the thicker airfoil will generate more lift.

But as someone pointed out above, the original Nobler design (of which I think the Brodak kit is probably closest, given that GMA worked with Brodak to develop it) is something you modify at considerable peril unless you are highly experienced. Despite my optimism about the Dixon thicker airfoil, I won't be at all surprised if the Brodak version is a better airplane.

In an old issue of Model Airplane News there is a three view of two of the first Noblers and the variances in them, ie, the one he actually built and the MAN 52 version. Neither had an 18% airfoil. One is listed with a 15.xx and the other with a 17.xx %. I forget the actual decimal numbers, but it is a thin airfoil.

Hi guys

I've just measured the root section on the Pat Johnston plan for the '57 Greenbox Nobler--13.57% including the flap.

The tip is 18.19% without any flap because the flap is trimmed to zero at the tip.