50+:1 15m sailplanes

Kirk Stant wrote:

The whole Sparrowhawk thing scares me to death! When I'm bashing
around at 130 knots, I want my glider to have a certain structural
authority!

Why do you think the SparrowHawk doesn't have "structural authority"?

Same thing when landing on some strange desert airstrip
for the first time.

Are you suggesting that the 15 meter LS-6 you fly would be easier to
land safely than the 11 meter SparrowHawk? Why would that be? Besides
being a lot smaller span (an asset when landing out, I think), the
SparrowHawk I flew landed slower than the 15 meter gliders I've flown.

And don't get me started on the whole unregulated
ultralight glider thing!!!
IMPORTANT SAFETY TIP FOR ANY NON-LICENCED
"PILOT" DROOLING OVER A SPARROWHAWK BROCHU Get the training, take
the damn test, get a licence,

Excellent advice, and echos what SparrowHawk people recommend.

and fly a real glider

I beg your pardon, but what isn't "real" about the SparrowHawk? From the
FAA registration database:

N-number : N40437
Aircraft Serial Number : 004
Aircraft Manufacturer : COLE GREGORY M
Model : SPARROW HAWK
Aircraft Year :
Owner Name : COLE GREGORY M
Owner Address : 2988 NE ROCKCHUCK DR
BEND, OR, 97701-6515
Type of Owner : Individual
Registration Date : 12-Jun-2003
Airworthiness Certificate Type : Not Specified


--
-----
change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Eric Greenwell wrote in message ...

I beg your pardon, but what isn't "real" about the SparrowHawk? From the
FAA registration database:

N-number : N40437
Aircraft Serial Number : 004
Aircraft Manufacturer : COLE GREGORY M
Model : SPARROW HAWK
Aircraft Year :
Owner Name : COLE GREGORY M
Owner Address : 2988 NE ROCKCHUCK DR
BEND, OR, 97701-6515
Type of Owner : Individual
Registration Date : 12-Jun-2003
Airworthiness Certificate Type : Not Specified

Eric,

Sorry, no disrespect intended, in your case the N number absolutely
makes it real. I have no problem with a registered glider flown by a
licenced pilot, which is obviously what you are - and from what I've
read it sounds like you are having a lot of fun. My fear if for the
unlicenced pilot flying an unregistered (or deregistered?)
Sparrowhawk. That is a dangerous situation, in my opinion. Push the
Sparrowhawk as a 1-26 replacement - or the saviour of fun soaring in
the US, fine, go for it!; sell it as an ultralight that "anybody" can
fly is scary! And sure, the manufacturer can insist on training, but
what happens when that Sparrowhawk is resold? Off comes the
N-number...

I guess I should shut up until I've been able to put my grubby little
paws on a real live Sparrowhawk. Or better yet a Duckhawk - can't
wait to fly against one of those and see if it is really a
breakthrough concept! Time - and a few competitions - will tell!

Kirk

Kirk Stant wrote:

Eric,

Sorry, no disrespect intended, in your case the N number absolutely
makes it real. I have no problem with a registered glider flown by a
licenced pilot, which is obviously what you are - and from what I've
read it sounds like you are having a lot of fun.

I don't own one, but I have flown one a couple of times, and have talked
with a couple of the owners quite bit.

My fear if for the
unlicenced pilot flying an unregistered (or deregistered?)
Sparrowhawk. That is a dangerous situation, in my opinion.

Not if the pilot is competent, of course, but I think I know what you
mean: potentially, the pilot might be untrained and outside the usual
network of oversight, such as biennials. Windward Performance knows
this, and if you look at their website, you will see that they don't
push this aspect of the glider. Windward Performance wants this to be a
successful glider, and crashes are bad news.

Push the
Sparrowhawk as a 1-26 replacement - or the saviour of fun soaring in
the US, fine, go for it!; sell it as an ultralight that "anybody" can
fly is scary!

As I said, they don't do this. Remember that Greg Cole, the designer,
makes his living designing real aircraft (e.g., he was the principal
engineer on Lancair's certified Columbia 300 and currently consults for
Adam Aircraft). It's my understanding every current customer will be a
licensed glider pilot by the time they take delivery (most of them were
before they ordered one, anyway).

Practically speaking, it's expensive enough that it's very unlikely that
an inexperienced person is going to by one, anyway.

And sure, the manufacturer can insist on training, but
what happens when that Sparrowhawk is resold? Off comes the
N-number...

If someone wants to fly, say, a 1-26 without a license or training,
there is little to stop them. Buy one, take it to dry lake, and car tow
it. Determined ignorance, stupidity, or arrogance can easily work
outside the system.

I guess I should shut up until I've been able to put my grubby little
paws on a real live Sparrowhawk. Or better yet a Duckhawk - can't
wait to fly against one of those and see if it is really a
breakthrough concept! Time - and a few competitions - will tell!

I'm waiting until they have a chance to put that motor in the SparrowHawk...

--
-----
change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

On Sun, 11 Jan 2004 09:40:25 -0800, Eric Greenwell
wrote:



I'm waiting until they have a chance to put that motor in the SparrowHawk...

Take a look at the movie clip of the Silent IN with the Jet engines. I
ran some numbers on the engines over the weekend and I'm convinced
I've seen the future of soaring.

Mike Borgelt

In article ,
Mike Borgelt wrote:
On Sun, 11 Jan 2004 09:40:25 -0800, Eric Greenwell
wrote:



I'm waiting until they have a chance to put that motor in the SparrowHawk...

Take a look at the movie clip of the Silent IN with the Jet engines. I
ran some numbers on the engines over the weekend and I'm convinced
I've seen the future of soaring.

Mike Borgelt

I've come to much the same conclusion as Mike. I'd use a single
more powerful turbine (maybe the 1500) instead of 2, but
the numbers seem to work for even fairly short fields.

The heat on the tail scares me though. Hmmm...how do we
get rid of the glider tail?

On 11 Jan 2004 14:39:20 -0700, (Mark James Boyd)
wrote:

The heat on the tail scares me though. Hmmm...how do we
get rid of the glider tail?

Why would you want that?
Many have tried it, an noone came even close to a conventional layout
(the compromise design Genesis was the only one that offered similar
handling wualities and performances as a conventional glider).

Having no tail is less of an advantage if your wing has twice the
drag...
Bye
Andreas

On 11 Jan 2004 14:39:20 -0700, (Mark James Boyd)
wrote:

In article ,
Mike Borgelt wrote:
On Sun, 11 Jan 2004 09:40:25 -0800, Eric Greenwell
wrote:



I'm waiting until they have a chance to put that motor in the SparrowHawk...

Take a look at the movie clip of the Silent IN with the Jet engines. I
ran some numbers on the engines over the weekend and I'm convinced
I've seen the future of soaring.

Mike Borgelt

I've come to much the same conclusion as Mike. I'd use a single
more powerful turbine (maybe the 1500) instead of 2, but
the numbers seem to work for even fairly short fields.

The heat on the tail scares me though. Hmmm...how do we
get rid of the glider tail?


The guys with the Silent don't seem to have a problem with the heat on
the tail - the two AMT 450 turbines seem to be mounted parallel to the
centerline. If this still worries you a V tail as on HP gliders or the
Salto is the easy answer.

I first thought of using the AMT1500 but when you do the numbers two
AMT450s (and soon the XP versions with about 10% more thrust) are
quite adequate for a 400kg glider. 50 feet at 500m takeoff run under
standard day sea level conditions seems doable, over 500 fpm rate of
climb at about 90 knots, single engine out climb of close to 200fpm at
70 knots. It makes a pretty good sustainer. (A real "turbo"!) Fuel
consumption on one engine is about 0.5kg/min , two is 1kg/min. Given
that a 2000 foot launch will only take about 4 minutes it is about as
fuel efficient as a launch behind a Pawnee.

Imagine self launcher with engine out capability and a decent climb
speed where you have significant energy for manouever even if both
engines fail!

Don't worry about ducting - extend the engine(s) on a short pylon.
They weigh so little and don't vibrate that this will be a very
lightweight structure, easy to extend and retract, solves any local
structural heat problems and the hole in the glider is so small, that
there will be minimal structural reinforcement required. The AMT 450
is 5.1" diameter and 10.7" long and weighs about 2.4kg (5 pounds or
so).

Great for motorising motorless gliders as the weight in the fuselage
is minimal. Convert part of the water tanks/bags for jet
fuel.60Kg(75liters) will give you one hour.

Now look at a Sparrowhawk

70kg empty

add say 10 kg for 1 x AMT450XP pylon and structural reinforcing

30 kg for 1 hours fuel.

add typical say 100 kg for pilot and chute etc

Only 210Kg!

One AMT 450 will self launch this adequately.
Two smaller engines may still be optimum for slightly increased thrust
and engine out capability.

Hope the Windward Performance guys have a plan to increase production
because if this works they might be swamped by customers.


These small turbines are still being developed - they will get better.
Engine pressure ratios are still only 4:1 or so, fuel consumption can
be improved.

Mike Borgelt

In article ,
Mike Borgelt wrote:
On 11 Jan 2004 14:39:20 -0700, (Mark James Boyd)
wrote:

In article ,
Mike Borgelt wrote:

I've come to much the same conclusion as Mike. I'd use a single
more powerful turbine (maybe the 1500) instead of 2, but
the numbers seem to work for even fairly short fields.

The heat on the tail scares me though. Hmmm...how do we
get rid of the glider tail?


The guys with the Silent don't seem to have a problem with the heat on
the tail - the two AMT 450 turbines seem to be mounted parallel to the
centerline. If this still worries you a V tail as on HP gliders or the
Salto is the easy answer.

I've never seen a turbine airplane design that allows the hot exhaust
to reach a control surface of the aircraft. The fact that the Silent
flew a few times in this configuration is not convincing to me.
If the owner would put it on a stand in a hangar and
run it for an hour with his face right in front of the rudder/stab,
I'd change my tune. I don't have any hard facts or figures,
but my intuition sets off some warning flags here...

I first thought of using the AMT1500 but when you do the numbers two
AMT450s (and soon the XP versions with about 10% more thrust) are
quite adequate for a 400kg glider.

The larger engine isn't for more thrust than two engines, but
just for the lower complexity of using one engine. Two engines are
best used in aircraft with high wing loading that carry
passengers through turbulence. Two engines in a light-wing
loaded aircraft is just unneccesary, IMHO. Engine failure is
a non-issue due to the glide ratio, and the reliability of turbines.
The added weight, wiring, two starters, fuel lines, etc. seem
silly if a single turbine can be used instead.

Great for motorising motorless gliders as the weight in the fuselage
is minimal. Convert part of the water tanks/bags for jet
fuel.60Kg(75liters) will give you one hour.

Figuring out how to manage fuel from two tanks is a minor
complexity, and being able to dump fuel should ensure
one doesn't fly "chinese style" (won weeng lo).
It does seem using the fuel as ballast is an excellent feature,
but I'd want to really think hard about fire dangers.
Perhaps use less flammable fuel? I guess there is quite a
variety of fuel choices available...

Now look at a Sparrowhawk
One AMT 450 will self launch this adequately.
Two smaller engines may still be optimum for slightly increased thrust
and engine out capability.

More power than adequate = better. One can always throttle
back for fuel savings. I suspect the designers used two
engines instead of one because the 1500 may not be readily tested/
available rather than due to the need for redundancy. Again,
I've flown some twins and they have their uses; a powered glider
isn't a good match for two turbine powerplants
(just overkill/expense)...

Hope the Windward Performance guys have a plan to increase production
because if this works they might be swamped by customers.

The Sparrowhawk may be ideal for this application, but other
light gliders also have comparable potential. And I personally
would want to see a competitor which could taxi well.
A self-launch glider which has trouble taxiing is less
interesting to me personally than something more flexible.
Besides, the noise may get one banned from the gliderport and forced
to use a gasp towered airport... ;P

Mark James Boyd wrote:

snip
The heat on the tail scares me though. Hmmm...how do we
get rid of the glider tail?

Duhhhhh... run the jet engine a little too long!? :-)

On Mon, 12 Jan 2004 07:46:52 +1000, Mike Borgelt
wrote:


Take a look at the movie clip of the Silent IN with the Jet engines. I
ran some numbers on the engines over the weekend and I'm convinced
I've seen the future of soaring.


Search for a glider called "Huetter 30 TS"... (look here, for example:
http://vintagesailplanes.de/Huetter30TS.htm). First flight was in
1960.

It later became the Libelle and Salto... but it failed miserably with
the turbine engine although it was a very good glider. Noise, fuel
consumption and bad climb rates were the killer factors.


Bye
Andreas