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Old Nov 10, 2011, 12:30 AM
G_T
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Airfoil and plane design work for 2012

Hello everyone,

I'm curious what sort of things you would be interested in having me develop over the winter, assuming I end up with the available time? I know there are not really enough Zone V2 wings flying for most people to have an impression of my more recent work so perhaps I'm asking a bit early...

I'm not saying that I'll necessarily do what is asked, but if one doesn't ask, the odds are lower!

So that you all know, I have a vertical stabilizer airfoil in progress specifically for rudderless. It should perform far better than an HT-23 or Edge-Vertical for that application. Different goals, different solution. So no need to ask for that. I should be releasing a prototype version 1 sometime soon for people to test (mostly launch height). I think the new foil will be noticably less draggy on launch; I'm sure it will be less draggy for normal flight and for turns.

Gerald
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Old Nov 10, 2011, 12:42 AM
Team Hong Kong F3K
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Hong Kong
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Thank you for all your work Gerald! I'm still not able to consistently get enough time to work on mine, but I'll still be following whatever you are developing with interest. Looking forward to the rudderless vertical foil
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Old Nov 10, 2011, 03:11 AM
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Hi,

What about something "less conventionnal", a flying wing for example.

Olivier
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Old Nov 10, 2011, 03:33 AM
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Vienna, Austria
Joined Jun 2008
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Hi Gerald,
thanks for all your work and thanks for sharing it as well!

Flap width does not get a lot of attention. Most DLG airfoils simply have 30% wide flaps and that's it. I wonder if it would be possible to design an airfoil with 35% flaps with identical performance but wider and therefore stiffer flaps. Or maybe going narrower would improve performance?

Or maybe even 30% or 35% at the root and 25% at the tip? Narrower and therefore lighter flaps at the tip should improve flutter resistance, and washout would increase with increasing camber which might improve induced drag.

I have no idea whether this all makes sense, maybe there are good reasons why things are as they are.

Regards,
Robert.
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Old Nov 10, 2011, 04:13 AM
flying monkey
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Europe
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Quote:
Originally Posted by G_T View Post
I'm curious what sort of things you would be interested in having me develop over the winter, assuming I end up with the available time?
How about working on your own quiver of planes first, so you don't have to fly old beat-up Taboos or Edge wings that have been rebagged a thousand times ?
Seriously, your work is much appreciated and there are already a lot of airfoils out there that people have not even tried, although they look promising (e. g.the Prototype HM 51-alternative or Poly mild/hot series).

Having said that, there are indeed a few things that could be worth investigating:

-finishing work on EDGE II series
-high wing loading / aspect ratio airfoils
-very wide (multi-surface) flap cords, very narrow flap cords (see Polaris)
-airfoils specifically designed for swept flying wings similar to Christian Behrens' "Little Wing" (maintaining good cl max even with negative flap deflections, rather flat cm vs. alpha curve)
-etc. pp.

Friedmar
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Old Nov 10, 2011, 04:27 AM
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Gerald,

I would be very interested to see what kind of performance can be achieved by airfoils designed for a turbulator (upper site just in front of the flap). To minimize the turbulent area a small flap width of (e.g. 24%) should be used.

I expect that thicker airfoils with higher Clmax and a more straight Cl-alfa are possible. The higher drag coefficient of such airfoils during launch can be compensated by applying a wing with a higher aspect ratio.

Bas
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Old Nov 10, 2011, 05:18 AM
Festina lente
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Schoonhoven, the Netherlands
Joined May 2006
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I like the proposal of Bas. I think thats in the direction of the Twister II, if I'm not mistaken.

But I'm also curious of your CNC machine. I would also like to read flight reports from you own designed and build wings. That will give you the possibility of a more intens connection between theory and practice. Which would encrease the quality of your next designs. I can wait for another design....

I have to finish the pod mold, and assemble the parts I've already made. Then the Zone V2 is ready to fly. Together with my flying buddy we than have a nice fleet of DLG's to compare:

Twister I
Twister II
Supergee
Edge
Zone V2

Can't wait for that day.....
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Old Nov 10, 2011, 05:31 AM
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Quote:
Originally Posted by Berrie View Post
I like the proposal of Bas. I think thats in the direction of the Twister II, if I'm not mistaken.

Berrie,

it is certainly not in the direction of the Twister II.
As far as I am aware no studies are done (yet) to DLG airfoils designed for a turbulator.

Bas
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Old Nov 10, 2011, 05:57 AM
Festina lente
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Sorry for that hypothesis. I supposed that because the TII from Dennis has a turbulator at the outher wings.
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Old Nov 10, 2011, 06:24 AM
Chuck 'Em and Chase 'Em
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United States, NY, Plainview
Joined Aug 2005
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I know they are lousy for thermaling but why not do a design for the sport flyer.

How about a scale job.
The flying wing is cool too.
Personally I have a warm place for canards but as a DLG. I know, have all those issues but so what? think of the challenge! Maybe it cannot hold a candle to a standard config but it sure would be fun to fly and look cool on launch.

DLG Power Thermaler - make it look like a P-51, Spitfire but be able to thermal

I am a little tired of every design looking like every other design. When it comes to slope or thermal, there is a little more variety.

How's about a DLG launched - electric sailplane? I know rediculous but it could allow for an even smaller pack since you could get over 100 ft just from the DLG launch.

How's about a 40" DLG with the expectiations for travel/ kept at the job?

Again, i am suggesting the off the wall, not mainstream path. I like more bagged airfoil design, since that is what I can afford but something for those that pushes the performance up but for the sport flyer adn is different than what is normally flown.

I think I could really enjoy a 40", canard or power thermaler myself.

Frank
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Old Nov 10, 2011, 06:33 AM
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Quote:
Originally Posted by Berrie View Post
Sorry for that hypothesis. I supposed that because the TII from Dennis has a turbulator at the outher wings.
Berrie,

I have also tip turbulators at my Twister 2's. This is done to have a better aileron response when flying against stall speed.
See: http://www.rcgroups.com/forums/showt...ster+2&page=11

I have seen same kind of tip turbulators on the Tantalus, the Turbo 2007, the Sirius, the Polaris and the Salpeter. The airfoils on these planes are, however, not designed for turbulators.

Bas
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Old Nov 10, 2011, 06:34 AM
Chuck 'Em and Chase 'Em
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United States, NY, Plainview
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How's about design something for those who cannot launch so high?
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Old Nov 10, 2011, 07:41 AM
flying monkey
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Europe
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On airfoils designed for turbulators: I know at least two DLG specific airfoils that were designed for a turbulator at 70%. One is by Björn Schürmann (proprietary) and one by Ulf Lehnert (see link for coordinates). Both designers assumed that the aileron gap is sufficient for tripping the air flow which might not always be the case.

Quote:
Originally Posted by Fly2High View Post
How's about design something for those who cannot launch so high?
That has already been designed Frank. It is more or less a stick that requires a lot of ballast:
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Old Nov 10, 2011, 08:36 AM
Father of Fr3aK, DLG Pilot
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USA, OH, Worthington
Joined May 2002
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I've been playing with turbulators on Gerald's Zone V2 near the flapperon gap in the outer section of the wing. Right now it's "playing" but some more serious testing will be done this winter... and btw there's a reason I'm not gap sealing the Fr3aK Zones...

I'll second the notion that you need to work on your quiver first. We don't need you losing interest in DLGs because you don't have good stuff to fly.
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Old Nov 10, 2011, 09:26 AM
Chuck 'Em and Chase 'Em
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United States, NY, Plainview
Joined Aug 2005
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If Gerald wants to design, maybe we should counter his lack of a quiver and help him do what he loves by taking up a collection to purchase a plane for him. this way, we can send some appreciation his way for all his work, get him a plane to fly and allow him to continue doing what he loves most.

win - win - win.

Frank
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