First I should mention that the performance goals were very carefully
considered. One of the primary goals was to have extremely safe low
speed handling qualities. Good cross country performance was also
important. In most places it is uncommon for glider pilots to exceed
80 knots for very long. These high speed excursions have very small
effect on the overall speed of a task. Time spent climbing has a more
pronounced effect on task speed. So good climb was important, as well
as good performance in the "normal" speed range around 60 knots. It
was decided that it would be okay to trade some of the "high" (above
80 knots) speed performance to acheive the low speed handling
qualities. (The DuckHawk has nearly the exact opposite goals although
low speed handling is always important.)

I have flown with quite a few different types of gliders. Most of the
time, everyone was running around at about 60 knots, and there wasn't
any appreciable difference between anybody, so I think that Greg Cole
did a good job of finding out how most people fly and designing the
SparrowHawk to match. Not to mention, he far exceeded the overall
handling qualities of any other glider I have flown.

The only sailplane that I have flown side by side with through the
whole speed range was a DG-202. At low speeds, the SparrowHawk's sink
rate was less (I have yet to see a German glider that can outclimb the
SparrowHawk). At 50 - 60 knots, there was essentially no difference.
We flew along for a quite a way at 60 knots to be sure. So if you
believe DG's numbers, the SparrowHawk has a best L/D of better than
42:1!

At 70 knots, we saw the first indication that the extra wing loading
and flaps on the DG were helping it. The biggest difference in sink
rate between the DG and the SparrowHawk was at 80 knots.
Interestingly, at 90 and 100 knots, while the SparrowHawk still had a
higher sink rate than the DG, the difference was less than it was at
80 knots. I have been told that the airfoil on the DG is known to get
a separation bubble at high speeds, so this isn't all that surprising
I guess. I have also made a run at 70 knots for a few miles with an
ASW 24. It also had a little advantage at this speed, but he only
went about 1/2 mile farther before he turned back too. The biggest
reason for the difference I think is that I am flying at about 5 lb./
sq.ft. versus on the order of 8 lb./ sq. ft. So far there are 3
SparrowHawks with water ballast tanks. It will be very interesting to
see how they compare with similar wing loadings.

Doug Taylor

ps. I should note that while I have never claimed to be unbiased
about the SparrowHawk, I had no connection with the manufacturer
beyond friendship. That has changed as they recently hired me to help
get more planes out the door. So in a sense any future posts from me
about the SparrowHawk might have to be considered commercial.

(Gus Rasch) wrote in message . com...
Carbon fiber drivers,

I've heard alot of praise so far, and probably well deserved. I must
admit a growing fondness of the lightweight. But...

Has anybody measured the polar outside of the factory? Anybody fly
one side by side with something of similar performance to get a sense
as to whether the numbers are close/accurate? I am especially
interested in the upper end of the speed spectrum.

Grant4ever