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Mar 02, 2004, 05:53 AM
Be afraid!
Cuddles's Avatar
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Question

Asymmetric wing DLG


Hi all
Iíve read about an ďAsymmetric wing DLGĒ in the October number of Thermal talk and I think itís a stunning solution.

ďBy far the most interesting poly at the event was the one flown by Bill Watson. Just when you thought you have seen everything something drastically different comes along. There are very few things in aviation that are asymmetrical but Bill has come up with another. If you look at the photos below, his plane just looks wrong or possibly that there is a distortion in the photo. I can assure you the photo is correct. The first instinct is to say that thing won't work. Well many can attest that it does, and it works quite well. One side of the wing has a wider chord and shorter span while the other side has exactly the opposite. The reason for this is that Bill has offset the fuselage towards the outside of the launch circle to gain more inertia. Unfortunately, I was unable to get the exact specs but I did speak with Bill and he said he made it just to test the idea and did not have plans to fly it in the contest. It flew so well that he managed to make the top ten fly off flying this oddity for the majority of the rounds.Ē

But in those 5 months I havenít seed a thread in this forum in wich this solution has been even mentioned .Why?
Maybe itís just me and Mr Watson that think this solution is good!
Since I would like to adopt this solution for my first scratchbuilt SAL I would like to have some feedback.
Thanx in advance and best regards to you all.
Cuddles
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Mar 02, 2004, 11:33 AM
Be afraid!
Cuddles's Avatar
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Maybe just because it's ugly?
Mar 02, 2004, 01:20 PM
Pompano Hill Flyers
Radian's Avatar

Need pics or links


Pictures and links to this plane would help us to comment.

Radian
Mar 02, 2004, 09:07 PM
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John Gallagher's Avatar
Bill Watson's plane is not the first Asymmetrical dlg flown in competition. Breck Baldwin is a very well known dlg pilot on the east coast. In 2001, he competed with what he affectionatly called the 'three legged dog', including the BASS event. Here's a link to a few photos of his dlg.

http://www.sjsf.org/hlg901.htm
Last edited by John Gallagher; Mar 02, 2004 at 09:20 PM.
Mar 03, 2004, 05:55 AM
Be afraid!
Cuddles's Avatar
Thread OP
Oh my gosh
This is a three legged bastard!!!
Simply wonderful
Thank you very very much John.Iwould like to know some specs and all the theory that is inside this system.
Best regards
Cuddles
Mar 03, 2004, 09:33 PM
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Bill Mixon's Avatar
So.. Where is the picture of the Bill Watson design?

Bill
Mar 04, 2004, 12:47 AM
Dragons, WindMills, all Same
jcstalls's Avatar
Greetings,

Simple search, reveals much.

Jared
Mar 04, 2004, 09:48 AM
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Bill Mixon's Avatar
I've seen that picture and one other with one panel of the wing not totally in the picture. The picture above is from the side, and therefore doesn't show the planform very well. I thought he might have a better picture showing it from the top.
Notice he said look at the pictures below.. But he didn't put a picture...

A design like this will not fly the same at all speeds, so I can't see where the benifit in weight offset will make up for the difference.

Bill
Mar 04, 2004, 10:18 AM
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John Gallagher's Avatar
The three legged dog was heavy. Bill's rendition looks lighter.

There are two questions that need to be answered.
Does the design really give higher launches?
Does the design fly as well as conventional dlg's, including glide, penetration, and thermalling?


John
Mar 04, 2004, 11:35 AM
Be afraid!
Cuddles's Avatar
Thread OP
Good questions,John!
Who will answer?(certainly not me )
But let's keep in mind that my model will be 1 meter span(for transportation).Weight offset had lured me into this solution:
Bill,why you say"A design like this will not fly the same at all speeds"?I can't understand this .
Best regards
Cuddles
Mar 04, 2004, 12:20 PM
Registered User
It won't ever fly as well as a flapped dlg with an airfoil optimized for the use of camber/reflex depending on flight conditions. These asymmetric models are the same as any other conventional poly ship in the sense that they have a fixed airfoil that is the designers best compromise for all flight conditions. I enjoy poly ships of all types but they are at a disadvantage to flapped models which can reflexed for launch and upwind penetration and cambered for minimum sink when working lift.


Greg
Mar 04, 2004, 03:33 PM
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Bill Mixon's Avatar
Quote:
Does the design really give higher launches?
I can see where the mass offset would give higher launches, but the offset on the Watson plane appears to be small. I'd guess a few more feet maybe in launch height. But as Greg mentioned it's not going to be very efficient in the air so the extra height wouldn't really matter.

Quote:
Bill,why you say"A design like this will not fly the same at all speeds"?I can't understand this
Look at the lift / drag properties of a low aspect ratio wing vs those of a high aspect ratio. The outer panel of the three legged dog would perform poorly compared to the inner high aspect ratio panel. You can do the calculations and come up with various airfoils and get it as close as possible for best glide, but it will never be "right".

Bill
Mar 05, 2004, 04:06 AM
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Cuddles's Avatar
Thread OP
Oh...
So this system is useless...
Thanks for the explanation.
Mar 05, 2004, 06:19 AM
Registered User
Not that I think it would be worth doing, but just as an idea, could you make the mount between wing and fuse slide? For example, if you had forward and aft wing bolts and allow the mounts to slide on runners, but spring the mounts back to centre. On launch the fuse would slide out under centripetal force, giving you the extra inertia but as soon as the plane is released the spring would return the fuse to central. This would allow you to use a normal wing but possibly get the advantages of moving the fuselage mass outwards on launch. I've very little idea how badly the aerodynamics of an offset fuse would mess things up on launch and I suspect the system would be far too fiddly and heavy to implement at the sizes that DLG's operate at, but I thought I'd mention it...

Barny
Mar 05, 2004, 12:16 PM
Registered User
Cuddles:

I don't think anyone here has said that the idea is useless. For my part I simply said that it won't outperform a flapped glider throughout a range of potential flying conditions. If you have the interest and inclination to build a hand launch with an asymmetric wing go right ahead. I'm sure that everyone will be interested in your results.

Greg


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