Windward Performance Duckhawk

[TheSoarer151]

As of recent, I've been able to fly this glider thanks to the generosity of its owner. If the Condor administration is interested in developing it in a planepack, I have access to pictures, polars, sounds, and anything else that could be of interest. It could be a nice addition to Plane Pack 3 as it is competitive against the Diana 2 with its 50-1 glide ratio.

Best Regards,
Daniel Sazhin

[Andy1248]

So as everyone heads to Google to find out what this is:

http://windward-performance.com/duckhawk/

[OXO]

Hmmm... No winglets?

[simsoarer]

Maybe in plane pack 3 or condor v2........lol

[TheSoarer151]

Nope no winglets. The wing is so thin at the tip that their benefit would be marginal at best since the glider can thermal around 45 knots empty anyway (in my case with an 8.2 lbs/square foot wing loading). Furthermore, since it has a redline of 200 knots, the necessity for strengthening the outer portion of the wing would be very significant and would add more weight than any miniscule addition in performance.

There are three versions of the Duckhawk. All of them go to a wing-loading of at least 12 lbs/square foot. The one at the bottom end has a VNE of 160 knots, then the one which I am flying which has a maneuvering speed of 160 knots and VNE of 200 and lastly the one that has a VNE of 225 knots. It is a very sweet handling glider, empty and loaded with almost no tendency to drop a wing. The flaps and gear are electrically driven. Both are due to weight constraints as mechanical systems are heavier and in the case of the flaps, the flaps can handle greater loads and flutter constraints better than a human ever could. Right now, the system is driven by a toggle switch that gives you infinite range between 20 degrees of flap down to -4 degrees. In the future, it will have an "automatic" mode which is driven by an angle of attack sensor wherein the flaps will constantly change to be in the most efficient position at all times.

I think it would be a great addition to Condor.

Regards,
Daniel

[OXO]

Ther seems to be very little data on their site. Is there a polar?

[Olympia]

I take that as a joke. You have plenty other planes to get ready without bothering with yet another bathtub. Get real and get working!

[TheSoarer151]

OXO,

There is a theoretical polar provided by the factory which is in the manual. The glider has not been directly tested yet. However, for what it is worth, the observations provided by the factory polar translate very well into real flight. For instance, the polar indicates an almost non-existent drag bucket and that it has a wide range of thermalling speeds as a result. This works very well. Overall, compared to the ASW27 polar, it gains in the lower speed and the high speed ends. In the middle, it is slightly better. I have access to all technical data or could facilitate a discussion with the engineers at Windward Performance for you guys to get everything you need. Another interesting example is that Greg Cole went through his computer models and told us to thermal it with 17 degrees of flaps rather than 15. Bill Thar and I thought it was kind of insane to thermal with so much flap and then I tried it and wow! Those two degrees really grooved it in well into the turn.

Also as another observation, its huge advantage not only comes in straight line performance, but also in handling. It is as docile if not more than the LS4, even loaded. I've had the wing drop exactly once and that was due to a very sharp gust in a thermal and the recovery was very easy and quick. It is astonishing on such a laminar flow wing that the flow can be broken in such a predictable manner such to create such docile characteristics. Windward did this by having five airfoils throughout the wing.

One interesting thing about the glider is that it carries only 26 gallons of water, half of the 27. This is because the wings are so small that they simply did not have enough room to load it up more. In my case this gets the wing-loading to almost 11 lbs/square foot. However, if you load the glider up with more fixed ballast, it can go up to 12 lbs/square foot. I wonder how you guys would account for that.

Best Regards,
Daniel

[TheSoarer151]

This is an image of the polar. Bear in mind that the empty weight of this glider is 450 lbs and the gross is 960 lbs.

Best Regards,
Daniel