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Old Nov 27, 2012, 03:01 PM
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North Britain
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Cool
Facts About Flying Wings

Another one from the stuff my old mate sent to me a while back, only came across it the other day. Must be going senile to have missed it.

Looks as if it's a bit of Northrop publicity blurb extolling the virtues of the flying wing.
No real technical content, but an interesting read all the same.

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Old Nov 27, 2012, 04:43 PM
I don't like your altitude
Stupot46's Avatar
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Thanks for that,a good simple explanation of the controls.
According to this,every plane in the air should be a wing
Stuart
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Old Nov 28, 2012, 09:14 AM
less is more
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This is great Derfy! That's what I call marketing material. Can only guess at it's publication date. 1940's apparently. No author, no publisher, no date. Must be from the "War Department".

Cool

Kent
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Old Nov 28, 2012, 12:33 PM
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Cool find, Derfy, some of those illustrations are from the B-49 pilot's handbook which I think is still available from the Planes Of Fame museum gift shop. From the picture of a passenger version I'd guess that this might be the brochure to drum up post war business that they were sending out to the airlines

--Norm
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Old Nov 28, 2012, 04:22 PM
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And then the Govt TOOK all the documentation and MADE THEM
CHOP UP all the remaining FW's and smelt em down !

All cuz Jack didn't want to throw in with Consolidated.

Oh yeah, we definitely need More Gov't !

Bob
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Old Nov 28, 2012, 05:42 PM
Herk
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Northrop was obsessed with a great concept, but needed a bit more technology than what was available.

Through a very indirect connection I finally got to one of the N9M resurrection crew at Planes of Fame Museum where it was re-created.

He said that they have always flown the restored plane with the CG at 9 inches forward of the main wheel axle. The documents show that the axle is at 103 inches from nose, so CG is at 94 inches.

My calculations indicate that gives a 2% static margin based on a 25% MAC neutral point.

The Northrop drawings show a CG location of 99 inches from the nose which gives a SM of -2.5% which I could not get to fly.

Anyway I was pleased to finally find out that they are flying the full scale restoration at about the same SM that I arrived at with my little roadkill version.
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Old Nov 29, 2012, 10:17 AM
less is more
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I understand that one of Northrup's wings had a yaw instability problem. Could it be that the CG just needed to be pushed forward in order to tame that beast?

Kent
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Old Nov 29, 2012, 12:18 PM
Herk
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Quote:
Originally Posted by Knoll53 View Post
I understand that one of Northrup's wings had a yaw instability problem. Could it be that the CG just needed to be pushed forward in order to tame that beast?

Kent
I don't think they ever complained about yaw instability.

The issue you are referring to is probably the bomber's problem with Dutch roll. It had a mild case of that while flying in cruise conditions. It was an issue that appeared to affect bombing accuracy. They had come up with a fix for it, but Symington used it as a way of diverting the program away from Northrop and to the B-36.
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Old Nov 29, 2012, 01:03 PM
I don't like your altitude
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Herks,I recall you cast doubts on the drawings at the time,Good to see your conclusions verified.
Stuart
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Old Nov 29, 2012, 07:14 PM
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Symington and Odlum's pull killed Jack NORTHRUP's wings.

Jackie Cochron was his wife and they had lots of PULL in DC.

Another Gov't Overreach kind like Solindra et al yada yada yada
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Old Nov 30, 2012, 03:44 PM
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North Britain
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Quote:
Originally Posted by HerkS View Post
...The Northrop drawings show a CG location of 99 inches from the nose which gives a SM of -2.5% which I could not get to fly...
Don't really want to put the cat among the pigeons , but have a look at the attached graph.

Could this in some way explain Northrop's CG?

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Old Nov 30, 2012, 04:29 PM
Herk
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Virginia USA
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Quote:
Originally Posted by Derfy View Post
Don't really want to put the cat among the pigeons , but have a look at the attached graph.

Could this in some way explain Northrop's CG?

Well - yes that's a very interesting chart and the explanation behind it could possibly add quite a bit of useful information to the mix. In the NACA wind tunnel testing of the full size N9M prototype the data included indicated that they reckoned the NP was at 30% of the MAC.

The N9M version that I was discussing has an AR ~ 7, quarter chord sweep angle is ~22 degrees and the taper ratio is ~.25.

If sigma signifies taper ratio (sorry I don't have the book) then the graph would indicate that the the author recons the NP for that design is ~.28 vice .25MAC. That would somewhat explain Northrop's thinking. Though it doesn't quite get the theoretical value back to 30%.

Could you please extract a bit of the background explanation for the chart, and confirm that sigma does signify TR.?
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Old Nov 30, 2012, 05:04 PM
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Quote:
Originally Posted by HerkS View Post

...If sigma signifies taper ratio (sorry I don't have the book) then the graph would indicate that the the author recons the NP for that design is ~.28 vice .25MAC...
Herk, unfortunately I don't have the book either. Downloaded the image eons ago from I don't no where and only rediscovered it recently on my hard drive. I'm sure I was looking into Vortex Lattice Method (VLM) stuff at the time, so I'll investigate that morass tomorrow and post anything that I find.

As for sigma, I'm sure we can assume that it refers to the taper ratio.

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Old Dec 01, 2012, 07:50 PM
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Valparaiso, IN
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A flying wing airliner

Back in the late 50's, I recall an aero engineering prof at Purdue describing an airliner version of Northrop's flying wing. He said passengers sat stadium style and had a magnificent view. Well, part of that did come true. Flying coach today is as about as comfortable as a stadium seat - in the bleachers.
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Last edited by Jim Deck; Dec 01, 2012 at 07:51 PM. Reason: spelling
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