SparrowHawk - Can it run with the big dogs?

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

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

(Doug Taylor) wrote in message . com...
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,


Sounds like you are saying it wouldn't do well in SW USA. It's a
pretty poor day in Arizona that doesn't see ballasted standard class
ships running above 80kts and 95kt inter-thermal speeds are common.

Andy

"Andy Durbin" wrote in message
om...
(Doug Taylor) wrote in message
. com...
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,


Sounds like you are saying it wouldn't do well in SW USA. It's a
pretty poor day in Arizona that doesn't see ballasted standard class
ships running above 80kts and 95kt inter-thermal speeds are common.

Andy

Andy's right. Damn, Doug, I carry more ballast than your gross weight.

My 500Km XC last week averaged 105 Kts interthermal cruise with 24%
thermalling, M=2Kts on the glide computer and 500 pounds of water in the
wings. I can dump that ballast and continue at 6 pounds wing loading.

Big wings rule. Good performance from little wings is an illusion.

Bill Daniels
Nimbus 2C (III)

(Andy Durbin) wrote in message . com...

Sounds like you are saying it wouldn't do well in SW USA. It's a
pretty poor day in Arizona that doesn't see ballasted standard class
ships running above 80kts and 95kt inter-thermal speeds are common.

Andy

Same here in Northern Illinois, show me someone who's doing 60...
They shouldn't try to sell a 5lb/sqft. lightweight as a 15-m class replacement

Herb, J7

In article kCGwc.58852$Ly.35225@attbi_s01, says...
I have flown with quite a few different types of gliders. Most of the
time, everyone was running around at about 60 knots,


Sounds like you are saying it wouldn't do well in SW USA. It's a
pretty poor day in Arizona that doesn't see ballasted standard class
ships running above 80kts and 95kt inter-thermal speeds are common.

Andy

Andy's right. Damn, Doug, I carry more ballast than your gross weight.

My 500Km XC last week averaged 105 Kts interthermal cruise with 24%
thermalling, M=2Kts on the glide computer and 500 pounds of water in the
wings. I can dump that ballast and continue at 6 pounds wing loading.

Big wings rule. Good performance from little wings is an illusion.


Some pilots are magicians, though, aren't they?

Now, now, Bill: you're just teasing us, aren't you? 20 Meters is needed
to get "good performance"? Do you really think a ballasted SparrowHawk
would fly at 60 knots in Arizona conditions?

Doug was reporting on comparisons with gliders flying in the SAME air,
not air separated by 1500 miles!

I'm curious: what is the maximum span that qualifies as "little wings"?
--
-------
Eric Greenwell USA

"Eric Greenwell" wrote in message
t...


Do you really think a ballasted SparrowHawk
would fly at 60 knots in Arizona conditions?

--
-------
Eric Greenwell USA

No, I think it would fly as fast as it could to escape the 10+ knots sink
between thermals and hit the ground before it got to the next one. Ballast
a Sparrowhawk? With what, an eyedropper?

I'm kidding, Eric, but small wings do work best in a narrower range of
thermal strengths and wing loading. In monster Southwest thermals, tight
turning radius is discounted since even the biggest and heaviest gliders can
center them. Big wings also provide the reach needed to get to the next
thermal that may be 20 miles away.

The Sparrowhawk will have a BIG advantage when the thermals are too small
for the bigger gliders to center them.

I like the idea of LIGHT gliders that are easy to rig but make them big and
strong to carry a lot of ballast. Contrary to conventional wisdom, wingspan
is the easiest and cheapest way to get more performance.

Bill Daniels

Bill Daniels wrote:

The Sparrowhawk will have a BIG advantage when the thermals are too small
for the bigger gliders to center them.

It sounds like an average European weather

/Janos