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Old Aug 19, 2014, 07:07 PM
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winnipeg
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Flying wings and thermals: YES YOU CAN!

Just pulled off a 30 minute thermal duration flight in front of witnesses with this flying wing. Some specs: Span , 60 inches. Weight 62 OZ's. Wing loading, 13.3 oz sq. ft. Flew hands off, a big help at the 1500-2000 feet altitude it was at for the duration.
Caught the thermal a couple of minutes into the flight at 500 feet and started working it mostly as a joke, never thought I could get any altitude with this heavy thing. Imagine my surprise as it went through 1000 feet after a couple of minutes!
Would like to see what a dedicated motor glider or pure glider flying wing could do, could be some serious competition for the conventional gliders.
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Old Yesterday, 04:03 AM
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Nice looking bird you have there!
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Old Yesterday, 04:14 AM
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thats not a flying wing
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Old Yesterday, 07:43 AM
I don't like your altitude
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Originally Posted by helljunkie13 View Post
thats not a flying wing
Yes it is;plank configuration.The tail boom is the longest I've seen,but still a flying wing.
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Old Yesterday, 07:47 AM
I don't like your altitude
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Originally Posted by builder View Post
Just pulled off a 30 minute thermal duration flight in front of witnesses with this flying wing. Some specs: Span , 60 inches. Weight 62 OZ's. Wing loading, 13.3 oz sq. ft. Flew hands off, a big help at the 1500-2000 feet altitude it was at for the duration.
Caught the thermal a couple of minutes into the flight at 500 feet and started working it mostly as a joke, never thought I could get any altitude with this heavy thing. Imagine my surprise as it went through 1000 feet after a couple of minutes!
Would like to see what a dedicated motor glider or pure glider flying wing could do, could be some serious competition for the conventional gliders.
That's a beauty!Any particular reason for the long boom?
Have a look at the Nurflugal forum,one or two wings on there designed with thermal flight in mind.
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Old Yesterday, 07:57 AM
buyer of the farm
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Originally Posted by Stupot46 View Post
Yes it is;plank configuration.The tail boom is the longest I've seen,but still a flying wing.
Technically it passes as a literal test. In fact it violates the spirit of a flying wing and is nothing but a conventional layout without a horizontal stabilizer, which it would probably fly better if it had one.

I wouldn't want one. It's not a wing in spirit. Whether it thermals or not is irrelevant. This is just a cheat.
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Old Yesterday, 08:19 AM
I don't like your altitude
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Originally Posted by Rockin Robbins View Post
Technically it passes as a literal test. In fact it violates the spirit of a flying wing and is nothing but a conventional layout without a horizontal stabilizer, which it would probably fly better if it had one.

I wouldn't want one. It's not a wing in spirit. Whether it thermals or not is irrelevant. This is just a cheat.
So where do you draw the line?
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Old Yesterday, 10:12 AM
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Anything that relies on the main wing for pitch stabilization and does not use a horizontal stabilizer is considered a flying wing. It doesn't matter if it has a vertical stabilizing fin or not or where and how they are located. For example, the Messerschmitt 163 Komet, a very successful full size design, or the Alula, a very popular light lift slope wing.
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Old Yesterday, 10:33 AM
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Originally Posted by Rockin Robbins View Post
it violates the spirit of a flying wing and is nothing but a conventional layout without a horizontal stabilizer, which it would probably fly better if it had one.
It's a spiritual issue?
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Old Yesterday, 11:23 AM
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Old Yesterday, 12:12 PM
I don't like your altitude
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It's a spiritual issue?
Thuringia
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Old Yesterday, 12:42 PM
buyer of the farm
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So where do you draw the line?
I'd draw the line at the fuselage, the elimination of which is the reason for selecting a flying wing to begin with. That design is an emasculated conventional design for the purpose of claiming it's a wing. The essence of the flying wing is the WING!

When the Convair B-58 Hustler came out, this was ten years after the famous Northrup N-1M, N-9M, XB-35, and XB-49 flying wings. The B-58, a standard layout delta was NEVER referred to as a flying wing. The reason? They didn't consider it so.

The Dictionary of Aeronautical Terms, by Dale Crane, third edition, page 224 says "A flying wing is a tailless, fixed wing aircraft that has no definite fuselage, with most of the crew, payload, and equipment being housed inside the main wing structure." This is in reference to real aircraft, not model aircraft but why should definitions differ between model and full-size?

It seems that flying wings (get a clue from the name!) are so cool that everybody is jostling for room under the umbrella. My Radian is not a flying wing if I rebalance it, set up ailerons as elevons and remove the horizontal stabilizer. Yet it would have the same layout as the above plane. It would certainly fly worse than the original Radian and the only excuse for the mutilation would be so I could claim to have a flying wing and bask in the cool aura thereof. I'd be a fraud.

A true flying wing may have vertical surfaces, but those surfaces are so close to the CG that they have no function in yawing the plane, stabilizing its direction or turning it if you stick a rudder on it. The only thing you get is drag. The Flite Test boys mounted rudders on a chevron flying wing and turned the heck out of them. They were great air brakes but didn't yaw the plane. Then they installed thrust vectoring in the horizontal direction with plus and minus about 30 degrees of rotation. They vectored all over the place to no visible effect on the flying wing. Flying wings don't fly like conventional planes. When you hang a stick out the back and mount a weather vane on it, you are talking conventional aerodynamics, not flying wing aerodynamics.

Flying wings are stabilized in yaw by differential drag. With no yaw, drag on the two wings are equal. But through the use of toed-in vertical surfaces on the end of the wings or simply cutting a straight up and down notch at about a 45 angle in the end of the leading edge of the wing, ala CrashTestHobby.com Assassin, when the plane yaws more drag is created in the leading wing while drag is reduced in the trailing wing. The drag differential cancels out the yaw, reestablishing straight ahead flight. This is all unexpected and probably counterintuitive, like many things relating to real flying wing flight.
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Old Yesterday, 01:54 PM
buyer of the farm
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It's a spiritual issue?
ALL flying is a spiritual issue.
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Old Yesterday, 04:21 PM
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I'd draw the line at the fuselage, the elimination of which is the reason for selecting a flying wing to begin with.
But what if all your stuff won't fit in a 10% thick airfoil? I'm repairing a full size airplane right now that everybody has been calling a flying wing for the last 40 years yet this airplane actually has two complete tails with both vertical and horizontal units see attachment. In addition we couldn't fit a full size person into the 19% airfoil so it has a stubby fuselage and not as nice looking as the one in the picture. It definitely is preferable to avoid having any non-lifting surface but one should remember that even Northrop and the Horten brothers usually had an assortment of bumps and/or fins on their airplanes. Also Northrop named the Avion model 1 "the Flying Wing" and trademarked that name even though the Model 1 had a twin boom tail. So, really, what's the point of being a purist? Remember we don't get rid of the tail, we just hide it


Quote:
That design is an emasculated conventional design for the purpose of claiming it's a wing. The essence of the flying wing is the WING!
Everybody's got to start somewhere... look at the Avion M1

--Norm
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Last edited by nmasters; Today at 08:37 AM. Reason: gramar &speln'
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Old Yesterday, 06:27 PM
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So Rockin, all Zagi's and their variants are not real flying wings because they use fins, and/or pods and fairings for equipment that could qualify as a fuselage? Good luck telling thousands of people that.


Stupot, The reason for the "long" boom is for good yaw stability at low airspeeds. It's actually only 14 inches, just looks longer in the pictures. I still get a bit of a wobble if I'm not smooth on the sticks at low speed, the fin could probably be 25% larger for optimum performance.
This is actually my first wing without a lot of sweep, I was testing out the platform against previous versions which had a fair amount. Conclusion: Not enough of a difference in performance to worry about, the airfoil seems to be the determining factor as far as efficiency goes.
It also is different from the rest in that the square center section is hollow, I plan to eliminate the fuselage in future versions and house the equipment inside a swept wing. This is done for efficiency sake, one less source of parasitical drag, but I'm not a fan of wing tip fins so I will have to do a work around for that.

You usually never get something for nothing in aviation, hollow wings have their own structural disadvantages. Probably as much time is spent on making a strong hollow wing as you would building a fuselage, something to think about if you like to prototype something fast using foam core wings.
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