Kestrel 19 info wanted.

[Glidingstuff[_2_]]

Hi all

Anybody got any links to a Kestrel 19 T59D owner group,pages etc?

I have obtained a broken one for a long term project and want to obtain any info that is available re parts, mods and drawings.

I remember from somewhere talk of a one piece canopy ala DG mod.

Any info much appreciated.

E-mail me at p_buchanan(at)rocketmail.com

Cheers

Paul

[C-FFKQ (42)]

Hi Paul,

I own a T.59D (1789) and love it :) A bit heavy to rig, but it handles my size and weight.

There is a Yahoo! group called "Kestrel401" that caters to the Kestrel crowd. It's not very active, but the people are fairly decent and responsive. You'll find the various approved mods there, as well as the TNs and ADs (there are 2 annual-check ADs). The PoH is also there. The various mods were designed by the factory as they went through series production (there are 4 series), including enlarging the rudder and adding an anti-balance tab to the elevator (standard in series 2 and later). There was one (two?) modified to have a double-panel spoiler, but it wasn't approved for general use and apparently didn't do much except make more noise.

Some support for the type is available through Glasfaser at www.streifly.de.. Slingsby is now known as Slingsby Advanced Composites and has various drawings for the Kestrel... at a price.

The Kestrel has no life limits, it's "on condition" for everything, although the rudder actuator has a slight design flaw (annual AD to check the weld joints: any cracks and it's to be replaced... not sure if there are any replacements available).

There are a few other Kestrel owners that follow r.a.s. so others may chime in.

Good luck getting your Kestrel back into the air!

- John

[Colin Roney]

At 22:29 27 May 2018, C-FFKQ 42 wrote:
>Hi Paul,
>
>I own a T.59D (1789) and love it :) A bit heavy to rig,
but it handles my
>=
>size and weight.
>
>There is a Yahoo! group called "Kestrel401" that caters
to the Kestrel
>crow=
>d. It's not very active, but the people are fairly decent
and responsive.
>=
> You'll find the various approved mods there, as well as
the TNs and ADs
>(t=
>here are 2 annual-check ADs). The PoH is also there.
The various mods
>wer=
>e designed by the factory as they went through series
production (there
>are=
> 4 series), including enlarging the rudder and adding an
anti-balance tab
>t=
>o the elevator (standard in series 2 and later). There
was one (two?)
>modi=
>fied to have a double-panel spoiler, but it wasn't
approved for general
>use=
> and apparently didn't do much except make more
noise.
>
>Some support for the type is available through
Glasfaser at
>www.streifly.de=
>.. Slingsby is now known as Slingsby Advanced
Composites and has various
>dr=
>awings for the Kestrel... at a price.
>
>The Kestrel has no life limits, it's "on condition" for
everything,
>althoug=
>h the rudder actuator has a slight design flaw (annual
AD to check the
>weld=
> joints: any cracks and it's to be replaced... not sure if
there are any
>re=
>placements available).
>
>There are a few other Kestrel owners that follow r.a.s.
so others may
>chime=
> in.
>
>Good luck getting your Kestrel back into the air!
>
>- John

G-DCTL has a one piece canopy.

[[email protected]]

"modified to have a double-panel spoiler, but it wasn't approved for general use and apparently didn't do much except make more noise"

Is more airbrake really needed on a Kestrel? I've never had a chance to fly one but seriously considered buying one several years ago and the pilots I talked to who had flown them seemed to think the brakes were fine and the landing flap setting made it even easier to do a steep approach - and then if you still needed more you could deploy the chute. Everyone who I talked to loved the ship.

One peculiarity of the Slingsby Kestrel, at least as certified in Canada, that I remember from that research is that a parachute, specifically a "back type parachute" is listed on the TCDS as required equipment. I've never seen that on any other glider. The German ships all seem to include a back type parachute or a back cushion of a specified thickness as required equipment but the Slingsby TCDS just flat out says you've got to carry a parachute.. I wonder if it was a typo that no one caught back in the early 70's when they were certifying it in Canada.

[C-FFKQ (42)]

On Monday, 28 May 2018 02:51:06 UTC-4, wrote:
> Is more airbrake really needed on a Kestrel? I've never had a chance to fly...

YES. Even the PoH mentions that the airbrakes aren't very effective! At best, they add about 1.5 kt of sink on my ship.

There are 35-degree landing flaps and, if needed, the drogue chute (I practice with it at my home field); the airbrakes are used to fine-tune the approach. Lots of planning and adjusting in the circuit to make a decent approach.

[[email protected]]

The brakes on the Kestrel are too far back on the wing to be very effective.
The Slingsby Kestrels had poor sutface accuracy too, thats why the extra 2 meters of wing only improved the LD by one point.
The ultimate ineffective use of span.

[BruceGreeff]

On 2018/05/29 02:16, wrote:
> The brakes on the Kestrel are too far back on the wing to be very effective.
> The Slingsby Kestrels had poor sutface accuracy too, thats why the extra 2 meters of wing only improved the LD by one point.
> The ultimate ineffective use of span.
>
If you reprofile the wings accurately and clean things up the glide does
improve. But it is still an old airfoil, so don't expect wonders. I
measured best glide at ~1:45 (after reprofile and adding with winglets.)

Still a wonderful aircraft. Comfortable, good handling predictable and
strong as a a house.

The one piece canopy is a DG200 unit. The complete kit is available from
Striefenedder - but seriously expensive.

As mentioned before - the airbrakes are not the most effective. But the
landing flaps work well, and like any open class glider, energy
management in the pattern is important. With full landing flap, full
airbrakes and the drogue chute out - if you can see it over your toes,
you probably can't reach it.
Too fast and it will float forever.

Jokes aside - the approach is very steep once the drag chute is out, but
I have only ever practiced a couple of times with it. The landing flaps
are enough...

[Mike Koerner[_2_]]

So there I was… just a foot or so off the ground with a full regiment of hay bales charging at me.
I was landing in a field just south of Big Pine - a farm field. The north side of the field had been recently cut and cleared. The south side was populated by hay bales. The wind was from the south. There was a road and high-tension power lines along the north side. The plan was to come in over the power lines and land in the first half of the field, short of the hay bales… without using the drag chute.
The thing about the drag chute on the Kestrel is that there two separate actuation cables with similar “T” handles but very different functions. One, labeled “Deploy”, presents the chute to the airstream whereupon it opens up and immediately generates enormous drag. The other, labeled “Jettison”, disconnects the chute at the point where the shrouds attach to the sailplane’s tail, whereupon there is no more drag.
The thinking behind this design was, no doubt, that you might misjudge your pattern with the chute such that you are not able to make it over a fence or trees at the approach end of the field. Rather than punish you for this misdeed, the plane allows you to jettison the whole thing, land without it (if you have enough room to do so) and walk back later to pick it up.
Of course, once you jettison it, there is no way to deploy it again during that flight. In fact, and this is the tricky bit, if you select jettison first and then subsequently deploy it, you will get both a deployment and jettison simultaneously, with no significant effect on drag.
All this means is that it’s important to select the correct control for any given occasion.
The other thing to realize about the drag chute on the Kestrel is that it is stunningly effective. You have to push the nose down when it opens to keep the plane flying. My brother, and partner in this particular aircraft, had warned me about this. He had also warned that the chute might not always open. It might get stuck. Or it might have already been inadvertently jettisoned (there was no way of knowing until the chute was deployed).
His advice was, if you elect to use the chute, do so on downwind so you can adjust your pattern for a steep descend if it opens, or not if it doesn’t.
I had practiced with the chute at the home field until I was comfortable with it use, but on this occasion, I decided it wasn’t needed. Alas, that is, until well into the flair. It seems that after the steep descent over the power lines I was carrying a bit more speed than expected. And though the hay bales had, from the air, looked to be widely scattered, from down here they seemed to have formed up into an impenetrable rank, at least for a 19-meter wing.
At that point I elected to deploy the chute to slow things down a bit - avoid engagement. As mentioned previously, this requires that I pull the correct handle, which means looking down in the cockpit to make my selection.
The self-preservation instincts of humans would be a fine subject for a grand dissertation. For our purposes, let it suffice to say that if you put your head down for any significant length of time while zooming over the ground at low level, you will instinctively pull back on the stick, at least a little.
Apparently, I ballooned up a bit before locating the correct handle. The chute opened immediately as evidenced by a sudden jerk. By the time I got my head back up looking out the canopy the plane had come to a complete stop about 8 feet in the air. I felt like one of those cartoon characters that walks off a cliff and has a moment to realize it before they start to fall. I had enough just enough time to say “Uh oh”; then WHAM!
Fortunately, the only damage was a broken axle. It had been cut down to about half its diameter just inside the fork as a weak link. The wheel was jammed up into the well sideways but still sticking out enough to protect the doors.
Hannes Linke turned a new axle for me and I was back in the air and off on new adventure by the next weekend.

[[email protected]]

I contacted Striefeneder about this a couple of years ago, they told me they no longer supply this mod.

[Frank Whiteley]

On Thursday, May 31, 2018 at 1:17:11 AM UTC-6, BruceGreeff wrote:
> On 2018/05/29 02:16, wrote:
> > The brakes on the Kestrel are too far back on the wing to be very effective.
> > The Slingsby Kestrels had poor sutface accuracy too, thats why the extra 2 meters of wing only improved the LD by one point.
> > The ultimate ineffective use of span.
> >
> If you reprofile the wings accurately and clean things up the glide does
> improve. But it is still an old airfoil, so don't expect wonders. I
> measured best glide at ~1:45 (after reprofile and adding with winglets.)
>
> Still a wonderful aircraft. Comfortable, good handling predictable and
> strong as a a house.
>
> The one piece canopy is a DG200 unit. The complete kit is available from
> Striefenedder - but seriously expensive.
>
> As mentioned before - the airbrakes are not the most effective. But the
> landing flaps work well, and like any open class glider, energy
> management in the pattern is important. With full landing flap, full
> airbrakes and the drogue chute out - if you can see it over your toes,
> you probably can't reach it.
> Too fast and it will float forever.
>
> Jokes aside - the approach is very steep once the drag chute is out, but
> I have only ever practiced a couple of times with it. The landing flaps
> are enough...

If left out overnight, dew may run down rudder and get the drogue chute wet thus is may freeze solid in before or in flight, depending on the location and season. Sealing it with tape overnight, or removing it and reinstalling before flight will avoid this.

Applies to all gliders with drogue chutes.

Frank Whiteley

[[email protected]]

Should be better than 45 after reprofiling, my 17m DG200, same airfoil is 45 factory, the 17m kestrel was 43, and the 19m was 44.

[john firth]

On Sunday, May 27, 2018 at 3:56:52 PM UTC-4, Glidingstuff wrote:
> Hi all
>
> Anybody got any links to a Kestrel 19 T59D owner group,pages etc?
>
> I have obtained a broken one for a long term project and want to obtain any info that is available re parts, mods and drawings.
>
> I remember from somewhere talk of a one piece canopy ala DG mod.
>
> Any info much appreciated.
>
> E-mail me at p_buchanan(at)rocketmail.com
>
> Cheers
>
> Paul

Installing a separate wheel brake lever allows the spoilers to be fully extended
without being restricted and you can apply full pressure to the brake.
Make the deploy/dump handles distinctly different to touch.
BTW a wet drogue chute may be slow to deploy; repack it every flight.
JMF

[Phil Chidekel]

On Friday, June 1, 2018 at 8:56:36 AM UTC-4, john firth wrote:
> On Sunday, May 27, 2018 at 3:56:52 PM UTC-4, Glidingstuff wrote:
> > Hi all
> >
> > Anybody got any links to a Kestrel 19 T59D owner group,pages etc?
> >
> > I have obtained a broken one for a long term project and want to obtain any info that is available re parts, mods and drawings.
> >
> > I remember from somewhere talk of a one piece canopy ala DG mod.
> >
> > Any info much appreciated.
> >
> > E-mail me at p_buchanan(at)rocketmail.com
> >
> > Cheers
> >
> > Paul
>
> Installing a separate wheel brake lever allows the spoilers to be fully extended
> without being restricted and you can apply full pressure to the brake.
> Make the deploy/dump handles distinctly different to touch.
> BTW a wet drogue chute may be slow to deploy; repack it every flight.
> JMF

Did they couple the spoilers and the wheel brake in the Kestrel 19? The 401 that I fly has a separate lever for the wheel brake... located just below the stick.

The handle for deploying the drogue chute (again, 401 S/N 48, not T59) is located on the left cockpit wall, vaguely similar in position to the release handle in the new Schleicher gliders. This is within easy reach from the spoilers/flaps, and I have been practicing grabbing it on the ground without looking. The jettison handle is on the lower right side of the instrument pod. Is this unchanged for the T59?

Needless to say, all of these handles can get pretty busy in the flare/rollout.

[Frank Whiteley]

On Friday, June 1, 2018 at 7:19:36 AM UTC-6, Phil Chidekel wrote:
> On Friday, June 1, 2018 at 8:56:36 AM UTC-4, john firth wrote:
> > On Sunday, May 27, 2018 at 3:56:52 PM UTC-4, Glidingstuff wrote:
> > > Hi all
> > >
> > > Anybody got any links to a Kestrel 19 T59D owner group,pages etc?
> > >
> > > I have obtained a broken one for a long term project and want to obtain any info that is available re parts, mods and drawings.
> > >
> > > I remember from somewhere talk of a one piece canopy ala DG mod.
> > >
> > > Any info much appreciated.
> > >
> > > E-mail me at p_buchanan(at)rocketmail.com
> > >
> > > Cheers
> > >
> > > Paul
> >
> > Installing a separate wheel brake lever allows the spoilers to be fully extended
> > without being restricted and you can apply full pressure to the brake.
> > Make the deploy/dump handles distinctly different to touch.
> > BTW a wet drogue chute may be slow to deploy; repack it every flight.
> > JMF
>
> Did they couple the spoilers and the wheel brake in the Kestrel 19? The 401 that I fly has a separate lever for the wheel brake... located just below the stick.
>
> The handle for deploying the drogue chute (again, 401 S/N 48, not T59) is located on the left cockpit wall, vaguely similar in position to the release handle in the new Schleicher gliders. This is within easy reach from the spoilers/flaps, and I have been practicing grabbing it on the ground without looking. The jettison handle is on the lower right side of the instrument pod. Is this unchanged for the T59?
>
> Needless to say, all of these handles can get pretty busy in the flare/rollout.

Prior owner of my 19 had the knob attach bolt fail on landing/takeoff inboard flap handle and the lever disappeared into the panel. IIRC, it was corrosion related. Something to maybe check occasionally.

Frank Whiteley

[Tony[_5_]]

ah yes the highest L/D to Lever ratio of any sailplane ever built!

[BruceGreeff]

On 2018/06/01 09:28, wrote:
> Should be better than 45 after reprofiling, my 17m DG200, same airfoil is 45 factory, the 17m kestrel was 43, and the 19m was 44.
>
Hi Mike

Unfortunately when they built the 19m they did not understand
aerodynamics so well I suspect. So they added a metre of thick draggy
wing at the root, and left the relatively high lift wingtips in place.

So - what you get is lots of extra profile drag. Best I could get off
GPS traces on long final glides in winter when the air is nice and still
- a little under 1:46... Maybe it is that she is 40+years old (1971 was
a LOOONG time ago). Maybe I am pessimistic. With properly profiled
airfoil but without additional mylar seals on the flaps - only internal
seals. I can honestly claim 1:45 is an achievable glide ratio. On a good
day it is maybe 1 better. But I never counted on that. The single piece
canopy may improve the sealing enough to make a difference there - the
amount of noise the canopy generates indicates that it is a source of
significant drag.

Keith modified a T59D by reprofiling the entire wing, and removing the
outboard 1.5m on each side, and reprofiling that part with thinner,
lower incidence airfoil and polyhedral plus a winglet. That got the
owner more like 1:51 - but the cost to do it commercially would be
prohibitive.

[[email protected]]

Its is my recollection that 1/2 meter was added at the root and the tip.
Airfoils 101, a thicker airfoil has a wider but shallower low drag bucket.

[[email protected]]

Anyone know how much the wings weigh?

[Frank Whiteley]

On Tuesday, April 23, 2019 at 7:17:11 PM UTC-6, wrote:
> Anyone know how much the wings weigh?

Mine are 208lbs and 206lbs.

[john firth]

On Sunday, May 27, 2018 at 3:56:52 PM UTC-4, Glidingstuff wrote:
> Hi all
>
> Anybody got any links to a Kestrel 19 T59D owner group,pages etc?
>
> I have obtained a broken one for a long term project and want to obtain any info that is available re parts, mods and drawings.
>
> I remember from somewhere talk of a one piece canopy ala DG mod.
>
> Any info much appreciated.
>
> E-mail me at p_buchanan(at)rocketmail.com
>
> Cheers
>
> Paul

Glide ratio; Slingsby modestly claimed 44 so the testing shows it
up close to the Nimbus 2, the competition in 1972.
G.Burton claimed that the wing root fillet solved the root flow
separation ( on the 17); 250 lbs of ballast made it go noticeably better.
( first 750KM in N. America)
John F

[john firth]

On Sunday, May 27, 2018 at 3:56:52 PM UTC-4, Glidingstuff wrote:
> Hi all
>
> Anybody got any links to a Kestrel 19 T59D owner group,pages etc?
>
> I have obtained a broken one for a long term project and want to obtain any info that is available re parts, mods and drawings.
>
> I remember from somewhere talk of a one piece canopy ala DG mod.
>
> Any info much appreciated.
>
> E-mail me at p_buchanan(at)rocketmail.com
>
> Cheers
>
> Paul

Not sure what was done on later models, but an independant wheel brake lever
(my mod) allowed full spoiler deployment; still indaequate!
JMF

[Paul T[_4_]]

I think the Kestrel 17 was measured at 41.1 by the idafleig - so 44.1
for the 19 is maybe about right - the 301 was I think measured at 39.1-
maybe more- the production 19's had 0.5m added at the root and 0.5m
at the tip. Manufacturers can claim all sorts of performance figures -
many are incorrect or 'theoretical' - surprised thought the idafleig
measured a js1c at 63:1. as Uys Jonkers recently stated in a video.

[[email protected]]

Thanks, Frank, for wing weights. Kicking tyres on a ship for sale. I have a little bit of time in an 18m with cg hook so 19m with nose hook doesn't sound intimidating - but curious for input on unassisted launching vs. variables such as x-wind, unmowed turf, etc.