Kestrel DG200 canopy mod.

At 21:45 11 June 2009, Jonathon May wrote:
In England Don Austin has put a one-piece canopy on a kestrel,it looks
like
a next generation ship,he dosen't know when to stop though, he also put
suspension,a disc brake and wing tips.

At 18:46 11 June 2009, Bruce wrote:
JS wrote:
Whilst you're waiting for the fix from Streifeneder, try different
flap settings on tow.
Jim
Now there's a lateral suggestion.

I shall take your suggestion and try it - but I still want the new
canopy.

Bruce

Take care with the flap setting, the limit speeds for positive flap are
very restrictive but one stage of positive does allow you to see the tug.

Bruce

I'm almost certain that I have seen at least one 17 meter Kestrel with
an aft hinged canopy. I don't know if this was a factory (Glasflugel)
canopy or an owner modification. Perhaps this could be adapted to
accommodate the 19 meter canopy as well.

Paul
ZZ















Bruce wrote:
OK

Anyone out there with experience in converting the T59D / 401 Kestrel
canopy from the awful removable thing with a hoop exactly where you want
to watch the tug, to a single piece.

Apparently there is an approved mod using a DG200 canopy.

Second question is - would there be anyone with such a canopy /frame
assembly for sale. As I understand it you need the entire DG hinge and
pedestal part too.

FWIW - I am considering modifying a Mark 2 Slingsby T59D Kestrel 19m -
though to the best of my knowledge the canopy and cockpit is identical
on the various Kestrels.

Any advice gladly received.

Cheers
Bruce

My name is Stephen, and recently purchased a Kestrel T59D in great shape. The Kestrel's handicap (Kestrel .89 versus Discuss .93) being in the neighborhood of more expensive ($250,000) aircraft--seems like a pretty good bet to put money into the old girl--albeit a 50 year old glass ship.

The bird is in amazing shape, yet needs some love in certain areas.

Being nearly seven feet tall as a pilot... options are to cut a hole in the bottom of the aircraft--which negates need for new brakes. Of course, I could opt for one of those new-fangled, sexy looking single canopies with a six inch larger bubble. Yeah, yeah, that is the ticket... Look cooler, go faster, and receive small increase in performance. Mmmmm... That is probably the better choice.

My hit list is simple...

1) Trailer gets new Timbren Axle-less axles. A two tone paint job--gray lower, white upper--with red seperation stripe and alloy designer rims. Electric brake upgrade, with new radial tires.

Inside will be painted, scabs and wounds from years of use fiberglassed over, and mounting hardware updated.

(About $3000 of love to make a 36 foot long viable and attractive for competition.)

2) Canopy modification... Going to reproduce Don Austins work for canopy. Would love to find that guy and actually ship my aircraft to him for design changes and review. The canopy is the biggest potential loss of L/D on the Kestrel--with any leak of air pressure devastating the laminar flow around the nose to wing section.

(Planning on $4000 of love, could go up to $6000 depending on cost of DG frame and hinge costs)

3) Wingtips... Have research done on benefits and size required. Again, mimicking Don Austins work in England, with small tweaks because of research values found to be optimal. Really curious as to the reality of theoretic values vs real world application of that theory in Don Austins bird--he loves the darn thing, so it must be exceptional.

(Planning on $6000 to $8000 of love on winglets. Improving L/D by 4--making former 44:1 closer to 48:1 with windshield mods, turbulators, and wingtips.)

4) Brakes and suspension... Improved brakes... Why improve brakes on a plane that is known to spin on the ground if you manage to fly it in hot? Because, the standard brakes are just too damn ineffective. Good speed control is important in any plane--add sixty five feet of wingspan and you have a wild bronking buck on your hands. The damned thing is designed to fly, and it wants to. The suspension will absorb the more aggressive landings, instead of my rumpus--connected--to--me (medical term, yeah.)

Again, stealing as much as Don Austin will let me from his experiences... Thinking maybe I should let him do all the work. If only I could find him. Plus the cost and hassle of shipping the bird... Really looking for a talented shop in the United States that is adventurous and not outrageous in price tag.

I will be the first to admit, I will have $30,000 into my sailplane... It will however run circles around others at competition, with the competitors spending $300,000 to arrive at the same place my $30,000 took.

Finish lines never lie...

Anyone know Donald Austin? Tell him I am going to need his help to compete in the 2020 year.

Personal Best to all you dedicated fliers out there,

Stephen

The first thing you need to do if you want a 19m go well is check the profile accuracy, Slingsby never managed to get it as good as the Germans. That’s why the 10 gained only one L/D point after adding 2 meters. Striefeneder used to do the canopy mod, but when I asked them said it was too expensive to be worthwhile, I’ve got a photo somewhere of one that was done, and it looks great. It won’t give you any better performance though.
In the UK several have been legally modified to 20M span. A slingsby Vega canopy fits exactly, as the front was from the Kestrel. Just a canopy frame and bubble without labour will be well more than you have budgeted.

At 21:29 15 November 2019, Charlie Quebec wrote:
The first thing you need to do if you want a 19m go well is check
the
profi=
le accuracy, Slingsby never managed to get it as good as the
Germans. That=
=E2=80=99s why the 10 gained only one L/D point after adding 2
meters.
Stri=
efeneder used to do the canopy mod, but when I asked them said it
was too
e=
xpensive to be worthwhile, I=E2=80=99ve got a photo somewhere
of one that
w=
as done, and it looks great. It won=E2=80=99t give you any better
performan=
ce though.
In the UK several have been legally modified to 20M span. A
slingsby Vega
c=
anopy fits exactly, as the front was from the Kestrel. Just a canopy
frame
=
and bubble without labour will be well more than you have
budgeted.


Don is starting to show his 80+years,I have not seen him at the
gliding club this year.

On Friday, November 15, 2019 at 2:15:05 PM UTC-8, Jonathon May wrote:
At 21:29 15 November 2019, Charlie Quebec wrote:
The first thing you need to do if you want a 19m go well is check
the
profi=
le accuracy, Slingsby never managed to get it as good as the
Germans. That=
=E2=80=99s why the 10 gained only one L/D point after adding 2
meters.
Stri=
efeneder used to do the canopy mod, but when I asked them said it
was too
e=
xpensive to be worthwhile, I=E2=80=99ve got a photo somewhere
of one that
w=
as done, and it looks great. It won=E2=80=99t give you any better
performan=
ce though.
In the UK several have been legally modified to 20M span. A
slingsby Vega
c=
anopy fits exactly, as the front was from the Kestrel. Just a canopy
frame
=
and bubble without labour will be well more than you have
budgeted.


Don is starting to show his 80+years,I have not seen him at the
gliding club this year.

Don is legendary, even stateside.

Because of him, I am endeavoring to make a Kestrel T59D fit a 279 pound, nearly seven foot tall pilot. Bought the plane and cannot even fly it until I get some mods done.

Have to make a 6 inch taller canopy. Have to move my body back two inches into the wing root--trading off my body weight as the wings water ballast.

I will be a rocket in the skies. Even the trailer will look amazing when I am done. I have a reasonable, yet serious budget to finish this airplane--I am so big in size, have had to plan this for years. If it was not for Bob, probably would not have ever entertained this large and risky of a project.

Figuring I am only a test pilot for the first fifteen minutes-then if all things work, I get to find out how well.

If anyone runs into Don, send him prayers from Stateside. The man has gone where very few venture, and I would like to recreate some of his work--only with my new data.

I think I can reach 48:1 with that aircraft.

Stephen G. Elder
Chief Operation Officer
Precision Innovation
Black Ops Division
(951) 515-6029

You will be 16kg + parachute over the maximum pilot weight 110kg, ( this is also the limit for the harness as standard) and out of the CG range without adding tail ballast, and worst of all, after that, significantly over the max weight of the none lifting parts. The Canopies are not blown, as they get too thin as they stretch, they are formed by forcing a plug upwards into the hot plastic.
Not trying to rain on you parade, but you should know this.

On Friday, November 15, 2019 at 1:29:43 PM UTC-8, Charlie Quebec wrote:
The first thing you need to do if you want a 19m go well is check the profile accuracy, Slingsby never managed to get it as good as the Germans. That’s why the 10 gained only one L/D point after adding 2 meters. Striefeneder used to do the canopy mod, but when I asked them said it was too expensive to be worthwhile, I’ve got a photo somewhere of one that was done, and it looks great. It won’t give you any better performance though.
In the UK several have been legally modified to 20M span. A slingsby Vega canopy fits exactly, as the front was from the Kestrel. Just a canopy frame and bubble without labour will be well more than you have budgeted.

I am having the fairing looked at, agreeing with you wholeheartedly. I am trying to put off doing paint and fiberglass work as long as I can--with the fiberglass being one of the birds better features.

Did people find the 20M mod worth the effort and expense??? I know lugging around 19M wings at close to 120 pounds a piece is going to get old.

Please do tell me more about where I can get a Vega Canopy--wanting to add six inches to the bubble, so I fit, being close to seven feet tall and 279 pounds. If I can get the attaching hardware--I will blow the bubble myself--so I was discounting the price, doing what I have skills to do.

Biggest thing for me, since I am updating the canopy anyway is to make egress and entry much more easy.

Thinking winglets offer the longer wing aspects, with many desirable traits having them. At 20M of wing, not sure there is much advantage left for winglets.

On Thursday, June 11, 2009 at 2:45:37 AM UTC-4, Bruce wrote:
OK

Anyone out there with experience in converting the T59D / 401 Kestrel
canopy from the awful removable thing with a hoop exactly where you want
to watch the tug, to a single piece.

Apparently there is an approved mod using a DG200 canopy.

Second question is - would there be anyone with such a canopy /frame
assembly for sale. As I understand it you need the entire DG hinge and
pedestal part too.

FWIW - I am considering modifying a Mark 2 Slingsby T59D Kestrel 19m -
though to the best of my knowledge the canopy and cockpit is identical
on the various Kestrels.

Any advice gladly received.

Cheers
Bruce

As usual ,I agree with Martin; I owned a K19 ( a 1972 model)for ten years and only sold it because I wanted to go 15M class.
It will indeed land very short if needed; landing flap, 45 kts and tailchute
as you flair will get you down inside 100M.
However, as supplied by Slingsby, there were a few things I wanted to change.
The cusp on the elevator added to provide "feel" at higher speeds made it
impossible to trim over 80 kts; cut it off to K17 elevator size;
anyway, I hated the trim system on the stick and locked it out except
for long glides.
The coupling of wheel brake to air brakes meant you had neither full
and ineffective airbrakes nor adequate wheel brake. Added separate brake lever.
The factory ballast bags held far too little (120 lb ??)
Made my own vinyl bags holding 250lb but the dump was too slow and wetted
the brake drum. Added a down tube ( also a filler tube) to the gear doors.
I reckoned that the max AUW was predicated on a rough field take-off
so not a problem from a smooth grass field.
For a chance at 750 km in Ontario I needed the weight ( add 50lbs inn the O2
tank holder) for cruise at 80-90 kts, and as Moffatt observed for the Nimbus 2
the higher wing loading makes it a different glider.
Proof of the pudding, on a good but not exceptional Ontario day, I passed
the 500KM mark past TP 2 in 4 1/2 hrs. For a 1970s design it was pretty good.
John Firth
an old no longer bold pilot.
PS never checked the profile accuracy but filled in the over spar dip.

On Thursday, June 11, 2009 at 2:45:37 AM UTC-4, Bruce wrote:
OK

Anyone out there with experience in converting the T59D / 401 Kestrel
canopy from the awful removable thing with a hoop exactly where you want
to watch the tug, to a single piece.

Apparently there is an approved mod using a DG200 canopy.

Second question is - would there be anyone with such a canopy /frame
assembly for sale. As I understand it you need the entire DG hinge and
pedestal part too.

FWIW - I am considering modifying a Mark 2 Slingsby T59D Kestrel 19m -
though to the best of my knowledge the canopy and cockpit is identical
on the various Kestrels.

Any advice gladly received.

Cheers
Bruce

Further to my earlier comments on desirable mods., I just remembered an important one.
As received new from the factory, 1972, I discovered that despite the vne
of 145 kts ( from memory); at sowewhere around 90 kts, a kick on the pedals would instigate rudder flutter, quite disturbing but killed by pressure
on both pedals.
AS in yugoslavia in 1972 , we never got to fly near Vb, let alone vne,
this was not a concern.
However, when I was repairing this glider 4 years later, I discovered
a reason for this flutter.
Normal composite fuselage construction uses plies at 45 deg to the axis
which yields the maximum torsional stiffness for the laminate.
My fuselage as laid up by the gnomes of Kirbymoorside, had plies running
parallel to the axis, ie 1.4 x less torsionaly less stiff.
(the first rudder flutter mode is torsional)
Moreover, the mass balance on the rudder was at the bottom , the wrong place
for torsional mass balance; it should be near the top.
Nothing I could do about the layup, but moving and adding to the mass
balance near the top of the rudder moved the flutter propensity
above 110kts, unlikely in a proper final glide.
These faults may have been corrected for later serial #s but I suggest
flutter testing in small increments above 85 kts.
John Firth Ottawa.