Diesel in a homebuilt?

[Lou]

Not that I plan to do this but I was wondering, if one was going to
plan to install a diesel in a homebuilt, what diesel would one put
in?
Lou

[Scott[_7_]]

Lou wrote:
> Not that I plan to do this but I was wondering, if one was going to
> plan to install a diesel in a homebuilt, what diesel would one put
> in?
> Lou
V-16 Caterpillar. :)

[Bill Chernoff]

Subaru is coming out with a diesel boxer style engine. I wonder what it
weighs?

[denny]

At Team Tango we have a builder who is planning to install a Delta
Hawk In a Tango 2. He has been waiting for several years and will
receive one of the first production engines when they begint to ship.
This year, again, they say this fall (and this time its for real). I
am not aware of any other diesels designed for airplanes that are
actually in play these days, but I haven't kept up on SMA, Thielert.
I have heard of financial problems at the companies. I would havae
financial problems trying to pay for one.

[Peter Dohm]

"Lou" > wrote in message
...
> Not that I plan to do this but I was wondering, if one was going to
> plan to install a diesel in a homebuilt, what diesel would one put
> in?
> Lou

Your location is not obvious from your email. In most of the world, diesels
are available in a wide variety. In the US, where fuel consumption is only
estimated from total mass flow and emission content at the exhasut, the
choices are currently quite limited, and I am really not very happy with any
of the choices. The 2 liter VW (Passat) is an all iron engine, and about
all I know is that it is about 100 pounds heavier than its gasoline
stablemate--which is partially aluminum. There are also V6 diesels offered
in the Mercedes E320 and the Jeep Liberty, but I know even less about them.
There are probably others that I haven't seen, and Isuzu has said that they
will be back in the diesel market when the regulations have stabilized.

Personally, I really do like the diesel idea--so I plan to take a very close
look if/when any of the lighter small diesels (such as the 2 liter Mercedes)
become available here.

Of course, there are a couple of avitaion diesels (Thielert being the most
widely known) that will bolt right in--but you have to fly a lot to save the
initial cost difference back in fuel.

You can correctly surmise from the above, that I tend to think in terms of
automotive conversion as soon as the disucssion drifts away from the smaller
Lycoming and Continental engines--and thier clones.

Peter

[Morgans[_2_]]

"denny" > wrote

> He has been waiting for several years and will
> receive one of the first production engines when they begint to ship.
> This year, again, they say this fall (and this time its for real).

Want to put any money down on him getting an engine this fall, or not?

I have been hearing that they are going to be shipping this "(X)" for at
least 3 years, now.
--
Jim in NC

[[email protected]]

On May 18, 9:46 pm, Lou > wrote:
> Not that I plan to do this but I was wondering, if one was going to
> plan to install a diesel in a homebuilt, what diesel would one put
> in?
> Lou

Currently there is the delta-hawk in the USA. There is an english 2-
cylinder 2 stroke of ~100hp that is based on the Jumo engines. There
are a couple of German companies, one with a couple of certified gear
reduced diesels, and there is an experimental diesel based on the
Mercedes smart engine. Also there is the new Subaru diesel, and the
latest pump-dues engine from VW. Ford also has a tight little
european TDI in the 1.5L range, but I don't know what the figures on
it are. I believe Lycoming makes a TDI for military applications,
(UAV's) )but I've not seen it offered commercially. In a nutshell, if
you aren't going delta-hawk, you will be looking overseas since
domestic diesel tech is about a decade behind the curve.

Of all of them the Jumo style engine in the UK peaks my interest, but
it's probably cost prohibitive. It has a lower parts count, and is
based on technology that has worked in aviation since the 30's. The
flip side is their aren't very many documented installations.

The automotive TDI's have direct injection systems that are computer
controlled. Essentially they reduce cylinder pressure by injecting
several pulses per stroke to simulate a gasoline combustion cycle.
This makes for a lighter engine, but you are dependent on common rail
injection, computer controls and greater sensitivity to fuel
contamination. ( I am speculating on the fuel contamination based on
injector design) Switching to mechanical injection on these engines
substantially derates them.

I am futzing around with a design based loosely on the old Packard
diesel with some modern features from other engines. At the moment is
is just a few CAD sketches, and I doubt if it will ever become a
reality. But I am convinced the Packard design coupled with turbo-
normalizing and modern casting/machining technology would provide the
lowest parts count, with the highest reliability.

[Mike Isaksen]

"Lou" wrote ...
> Not that I plan to do this but I was wondering, if one was
> going to plan to install a diesel in a homebuilt, what diesel
> would one put in?
>

What about the Light Sport Aircraft from InDus (???).
I think it's called a Thorpedo(???).
Memory says they flew one into Sun N Fun with a British made diesel
installed. They plan to market it outside the USA.
Go to ByDanJohnson dot com, he usually has the latest LSA stuff on his site.

[jan olieslagers[_2_]]

Lou schreef:
> Not that I plan to do this but I was wondering, if one was going to
> plan to install a diesel in a homebuilt, what diesel would one put
> in?
> Lou

Elaborating on earlier replies:

I know of two English designs, both aircraft-specific, both two-stroke:
see www.wilksch.com or www.dair.co.uk
Both are very rare, I never met one except on the maker's demo-planes.
I suspect their pricing is a bit prohibitive.
Also I seem to remember a third English design but have no details.

A couple of car conversions are flying in France, see one at
http://membres.lycos.fr/dieselis (in French only, regrettably)
and another at http://gazaile2.nmr7.free.fr/
both seem to suffer from engine weight.

In Germany, Thielert markets a heavily modified Mercedes diesel,
but this aiming at bigger planes. This engine powers the DA-40
and DA-42, highly successful in Europe these days.

And I once met a guy in Belgium who adapts Subaru petrol engines
mainly for autogyro use, I hope for the day he sets to work
on the Subaru diesel.

[stol]

On May 18, 9:31*pm, "Morgans" > wrote:
> "denny" > wrote
>
> > He has been waiting for several years and will
> > receive one of the first production engines when they begint to ship.
> > This year, again, they say this fall *(and this time its for real).
>
> Want to put any money down on him getting an engine this fall, or not?
>
> I have been hearing that they are going to be shipping this "(X)" for at
> least 3 years, now.
> --
> Jim in NC

They promised me mine in Augest of 2002, December at the latest. You
all know "the rest of the story".

[clare at snyder dot ontario dot canada]

On Mon, 19 May 2008 06:50:16 +0000, jan olieslagers
> wrote:

>Lou schreef:
>> Not that I plan to do this but I was wondering, if one was going to
>> plan to install a diesel in a homebuilt, what diesel would one put
>> in?
>> Lou
>
>Elaborating on earlier replies:
>
>I know of two English designs, both aircraft-specific, both two-stroke:
>see www.wilksch.com or www.dair.co.uk
>Both are very rare, I never met one except on the maker's demo-planes.
>I suspect their pricing is a bit prohibitive.
>Also I seem to remember a third English design but have no details.
>
>A couple of car conversions are flying in France, see one at
>http://membres.lycos.fr/dieselis (in French only, regrettably)
>and another at http://gazaile2.nmr7.free.fr/
>both seem to suffer from engine weight.
>
>In Germany, Thielert markets a heavily modified Mercedes diesel,
>but this aiming at bigger planes. This engine powers the DA-40
>and DA-42, highly successful in Europe these days.
>
>And I once met a guy in Belgium who adapts Subaru petrol engines
>mainly for autogyro use, I hope for the day he sets to work
>on the Subaru diesel.

Thielert just went bankrupt from what I heard last week.
** Posted from http://www.teranews.com **

[Peter Dohm]

<clare at snyder dot ontario dot canada> wrote in message
...
> On Mon, 19 May 2008 06:50:16 +0000, jan olieslagers
> > wrote:
>
>>Lou schreef:
>>> Not that I plan to do this but I was wondering, if one was going to
>>> plan to install a diesel in a homebuilt, what diesel would one put
>>> in?
>>> Lou
>>
>>Elaborating on earlier replies:
>>
>>I know of two English designs, both aircraft-specific, both two-stroke:
>>see www.wilksch.com or www.dair.co.uk
>>Both are very rare, I never met one except on the maker's demo-planes.
>>I suspect their pricing is a bit prohibitive.
>>Also I seem to remember a third English design but have no details.
>>
>>A couple of car conversions are flying in France, see one at
>>http://membres.lycos.fr/dieselis (in French only, regrettably)
>>and another at http://gazaile2.nmr7.free.fr/
>>both seem to suffer from engine weight.
>>
>>In Germany, Thielert markets a heavily modified Mercedes diesel,
>>but this aiming at bigger planes. This engine powers the DA-40
>>and DA-42, highly successful in Europe these days.
>>
>>And I once met a guy in Belgium who adapts Subaru petrol engines
>>mainly for autogyro use, I hope for the day he sets to work
>>on the Subaru diesel.
>
> Thielert just went bankrupt from what I heard last week.

True, as also reported on AvWeb, but...

I am obviously a slow learner, becuase it has taken me a bit more that a
half century to learn that "bankrupt", like the term "scape goat" from the
old testament, does not necessarily mean what we have been conditioned to
first presume. I really know less than nothing about German law, but in the
US "bankrupt" can mean just about anything from "they're toast" to "the
accountants require a further audit before proceding". To my eye, as a
layman, the story in AvWeb looked more like they just demanded a further
audit.

I am glad that I don't have any money, or scheduled production, at stake;
especially since any presumption that I might make would have little basis
in fact.

Peter

[Morgans[_2_]]

"Peter Dohm" > wrote

> Your location is not obvious from your email. In most of the world,
> diesels are available in a wide variety. In the US, where fuel
> consumption is only estimated from total mass flow and emission content at
> the exhasut, the choices are currently quite limited, and I am really not
> very happy with any of the choices. The 2 liter VW (Passat) is an all
> iron engine, and about all I know is that it is about 100 pounds heavier
> than its gasoline stablemate--which is partially aluminum. There are also
> V6 diesels offered in the Mercedes E320 and the Jeep Liberty, but I know
> even less about them. There are probably others that I haven't seen, and
> Isuzu has said that they will be back in the diesel market when the
> regulations have stabilized.
>
> Personally, I really do like the diesel idea--so I plan to take a very
> close look if/when any of the lighter small diesels (such as the 2 liter
> Mercedes) become available here.

One thing that everyone should keep in mind, is that automotive diesels run
on diesel fuel, and everyone wanting diesel engines for their airplanes is
going to want to use jet fuel.

Jet fuel does not have the good lubricating properties that diesel fuel has,
and may tend to wear out the automotive fuel pumps in short order.

I read somewhere that Thielert spent half of what they spent on
modifications to the engine, in designing a fuel pump that would be durable
enough.

Something to keep in mind.
--
Jim in NC
--
Jim in NC

[Dave S]

Morgans wrote:

>
> One thing that everyone should keep in mind, is that automotive diesels run
> on diesel fuel, and everyone wanting diesel engines for their airplanes is
> going to want to use jet fuel.
>
> Jet fuel does not have the good lubricating properties that diesel fuel has,
> and may tend to wear out the automotive fuel pumps in short order.
>
.....
>
> Something to keep in mind.

This issue was discussed on the Canard Aviation forum a year or so ago.
What I dont remember was if there were lubricity additives that could be
used to make up for this jet a shortcoming (something you spray in the
tank, like they do with Prist for anti-icing)

[Dave S]

Peter Dohm wrote:

> I am obviously a slow learner, becuase it has taken me a bit more that a
> half century to learn that "bankrupt", like the term "scape goat" from the
> old testament, does not necessarily mean what we have been conditioned to
> first presume. I really know less than nothing about German law, but in the
> US "bankrupt" can mean just about anything from "they're toast" to "the
> accountants require a further audit before proceding". To my eye, as a
> layman, the story in AvWeb looked more like they just demanded a further
> audit.
>
> I am glad that I don't have any money, or scheduled production, at stake;
> especially since any presumption that I might make would have little basis
> in fact.
>
> Peter
>

Essentially when the legal troubles broke regarding their creative
accounting, the note holders on their loans/bonds called their share
back in (demanded immediate payment).

The company isn't in a position to do that, so it goes in default.. So
you can have a good product, with an otherwise good company, get screwed
over by a few bad apples and place the company in receivership.

I would think the folks who hold the interest in the company could
replace the management and keep on trucking...

Im hoping thats not just wishful thinking.
Dave

[jan olieslagers[_2_]]

Dave S schreef:
> Peter Dohm wrote:
>
>> I am obviously a slow learner, becuase it has taken me a bit more that
>> a half century to learn that "bankrupt", like the term "scape goat"
>> from the old testament, does not necessarily mean what we have been
>> conditioned to first presume. I really know less than nothing about
>> German law, but in the US "bankrupt" can mean just about anything from
>> "they're toast" to "the accountants require a further audit before
>> proceding". To my eye, as a layman, the story in AvWeb looked more
>> like they just demanded a further audit.
>>
>> I am glad that I don't have any money, or scheduled production, at
>> stake; especially since any presumption that I might make would have
>> little basis in fact.
>>
>> Peter
>>
>
> Essentially when the legal troubles broke regarding their creative
> accounting, the note holders on their loans/bonds called their share
> back in (demanded immediate payment).
>
> The company isn't in a position to do that, so it goes in default.. So
> you can have a good product, with an otherwise good company, get screwed
> over by a few bad apples and place the company in receivership.
>
> I would think the folks who hold the interest in the company could
> replace the management and keep on trucking...
>
> Im hoping thats not just wishful thinking.
> Dave

from ther website www.thielert.de
<literal copy & paste>
The publication of the annual report will be postponed due to the fact
that the annual financial statements for the years 2003, 2004 and 2005
are probably incorrect and possibly void.
</copy>

Sounds like creative accountancy indeed.
The product is bound to be allright.
Detail: Thielert is apparently a holding company
(Thielert AG) with several subsidiaries.
The aviation subsidiary Thielert Aircraft Engines
was reported failing April 24th, parent company
Thielert AG went into receivership April 30th.

[jan olieslagers[_2_]]

Morgans schreef:

> One thing that everyone should keep in mind, is that automotive diesels run
> on diesel fuel, and everyone wanting diesel engines for their airplanes is
> going to want to use jet fuel.
>
> Jet fuel does not have the good lubricating properties that diesel fuel has,
> and may tend to wear out the automotive fuel pumps in short order.

The lubricity aspect is certainly important. But I'm not so sure
everybody will be wanting to use Jet A1. Just like many recreational
fliers bring their own mogas to the field, I can imagine pilots
bringing jerrycans of off-road diesel (coloured red in my country,
and in many other European countries I believe).
Those with a trailered plane can just stop at a petrol station, of course.

Ideally, both diesel and Jet-A1 could be used.
But with today's fuel prices, everyone makes his own compromise.

[Lou]

> Ideally, both diesel and Jet-A1 could be used.
> But with today's fuel prices, everyone makes his own compromise.

I'm going to show my ignorance again but Diesel and
Jet a1 can be used in a diesel engine?
Lou

[Uli]

Lou wrote:

> I'm going to show my ignorance again but Diesel and
> Jet a1 can be used in a diesel engine?

i would refer to the engine's manual to be safe; this can differ from engine
to engine. thielert's centurion 2.0 is certified for both, jet-a1 and
diesel. however, airplane manufacturers may restrict that; diamond's da-40
tdi is certified for jet-a1 only (according to the manual of an aircraft
equipped with the centurion 1.7).
the centurion 4.0 engine is designed for jet fuel only.

another aspect i'm not familiar with is if fuels sold as "diesel" are the
same in europe and the usa. thielert's internet site mentiones diesel fuel
according to european standard EN 590.


uli

[stol]

On May 19, 10:08*pm, "Morgans" > wrote:
> "Peter Dohm" > wrote
>
> > Your location is not obvious from your email. *In most of the world,
> > diesels are available in a wide variety. *In the US, where fuel
> > consumption is only estimated from total mass flow and emission content at
> > the exhasut, the choices are currently quite limited, and I am really not
> > very happy with any of the choices. *The 2 liter VW (Passat) is an all
> > iron engine, and about all I know is that it is about 100 pounds heavier
> > than its gasoline stablemate--which is partially aluminum. *There are also
> > V6 diesels offered in the Mercedes E320 and the Jeep Liberty, but I know
> > even less about them. There are probably others that I haven't seen, and
> > Isuzu has said that they will be back in the diesel market when the
> > regulations have stabilized.
>
> > Personally, I really do like the diesel idea--so I plan to take a very
> > close look if/when any of the lighter small diesels (such as the 2 liter
> > Mercedes) become available here.
>
> *One thing that everyone should keep in mind, is that automotive diesels run
> on diesel fuel, and everyone wanting diesel engines for their airplanes is
> going to want to use jet fuel.
>
> Jet fuel does not have the good lubricating properties that diesel fuel has,
> and may tend to wear out the automotive fuel pumps in short order.
>
> I read somewhere that Thielert spent half of what they spent on
> modifications to the engine, in designing a fuel pump that would be durable
> enough.
>
> Something to keep in mind.
> --
> Jim in NC
> --
> Jim in NC

Jim is on target here. The latest scheme is for truckers to aquire JET
A through several tricky means and then blend mineral oil into it at
the rate of 1 quart for 100 gallons of fuel. That adds the lubricity
into it to prevent wear on their fuel systems, the Jet A is not dyed
red so the tax man can't find out and they are able to purchase 10,000
gallons of jet at about half the cost of diesel. Word on the street
is the oil of choice is Aeroshell 100, because of the ashless
dispersents that are blended into it, supposably that prevents weird
things happening to the fuel injection system. Lets see, @ 6 bucks a
quart for the oil that makes it cost 6 cents a gallon to reformulate
Jet A to diesel... Sounds sweet to me. <G>

[Peter Dohm]

"Morgans" > wrote in message
...
>
> One thing that everyone should keep in mind, is that automotive diesels
> run on diesel fuel, and everyone wanting diesel engines for their
> airplanes is going to want to use jet fuel.
>
> Jet fuel does not have the good lubricating properties that diesel fuel
> has, and may tend to wear out the automotive fuel pumps in short order.
>
> I read somewhere that Thielert spent half of what they spent on
> modifications to the engine, in designing a fuel pump that would be
> durable enough.
>
> Something to keep in mind.
> --
> Jim in NC
> --
As of a few months ago, lubricity was a very serious problem in Ultra Low
Sulpher Diesel fuel, because the quickly implemented refining process tended
to strip most of the lubricants from the fuel. I have no idea whether that
caused it to have better, or worse, lubricity than Jet-A, but there are a
couple of high pressure lubricants offered specifically to solve the
problem--plus some "home brew" fixes.

BTW, the solution mentioned elsewhere in this thread is new to me; but
diesel airport vehicles have run on Jet-A as long as I can recall and AFAIK
all of the military Hummers are specified as diesel.

Comments???

Peter

[jan olieslagers[_2_]]

stol schreef:
>they are able to purchase 10,000 gallons of jet at about half the cost of diesel

????!!!! In what part of the world is Jet A1 cheaper than (uncoloured)
diesel ????

[Lou]

On May 20, 10:49 am, jan olieslagers >
wrote:
> stol schreef:
>
> >they are able to purchase 10,000 gallons of jet at about half the cost of diesel
>
> ????!!!! In what part of the world is Jet A1 cheaper than (uncoloured)
> diesel ????

Wow, I'm learning a lot.
Lou

[stol]

On May 20, 9:49*am, jan olieslagers >
wrote:
> stol schreef:
>
> >they are able to purchase 10,000 gallons of jet at about half the cost of diesel
>
> ????!!!! In what part of the world is Jet A1 cheaper than (uncoloured)
> diesel ????

The USA ..............

[Jim Logajan]

stol > wrote:
> On May 20, 9:49*am, jan olieslagers >
> wrote:
>> stol schreef:
>>
>> >they are able to purchase 10,000 gallons of jet at about half the
>> >cost of
> diesel
>>
>> ????!!!! In what part of the world is Jet A1 cheaper than
>> (uncoloured) diesel ????
>
> The USA ..............

In what year? ;-)

The facts, as best I can find:

Airnav provides an average retail price for Jet-A on a per state basis:
http://www.airnav.com/fuel/greatdeals/pocket?type=A

National average for Jet-A appears to be around $5.25/gal or so.

The U.S. DOE provides an average retail price for diesel on a regional and
national basis:
http://tonto.eia.doe.gov/oog/info/wohdp/diesel.asp

National average for diesel appears to be around $4.74/gal or so.

Of course that is retail price. No clue on wholesale. Still, Jet-A appears
to be more expensive at retail so I'd be surprised if wholesale prices for
for both would invert that relationship to the extent claimed. Not
impossible, just not credible absent supporting material.

[[email protected]]

On May 20, 12:08 am, "Morgans" > wrote:
> "Peter Dohm" > wrote
>
> > Your location is not obvious from your email. In most of the world,
> > diesels are available in a wide variety. In the US, where fuel
> > consumption is only estimated from total mass flow and emission content at
> > the exhasut, the choices are currently quite limited, and I am really not
> > very happy with any of the choices. The 2 liter VW (Passat) is an all
> > iron engine, and about all I know is that it is about 100 pounds heavier
> > than its gasoline stablemate--which is partially aluminum. There are also
> > V6 diesels offered in the Mercedes E320 and the Jeep Liberty, but I know
> > even less about them. There are probably others that I haven't seen, and
> > Isuzu has said that they will be back in the diesel market when the
> > regulations have stabilized.
>
> > Personally, I really do like the diesel idea--so I plan to take a very
> > close look if/when any of the lighter small diesels (such as the 2 liter
> > Mercedes) become available here.
>
> One thing that everyone should keep in mind, is that automotive diesels run
> on diesel fuel, and everyone wanting diesel engines for their airplanes is
> going to want to use jet fuel.
>
> Jet fuel does not have the good lubricating properties that diesel fuel has,
> and may tend to wear out the automotive fuel pumps in short order.
>
> I read somewhere that Thielert spent half of what they spent on
> modifications to the engine, in designing a fuel pump that would be durable
> enough.
>
> Something to keep in mind.
> --
> Jim in NC
> --
> Jim in NC

Not I,

And I dare say there are a few other fellows on this board who are
looking at SVO, Biodiesel, and Ethanol as practical alternatives.
Ethanols lower energy density means you have to carry more of it, but
since it is more resistant to detonation you can run substantially
higher compression ratios. I don't imagine it will be too long before
the bean patch is replanted with corn or rape seed and fuel is boot-
legged right on the tarmac.

In central and south america ethanol has been in aviation use for a
while. Biodiesel has better temperature tolerances than SVO, but it
still isn't serviceable without additional engineering due to gelling.
Given that is the case, there is basically no gain from using
biodiesel over SVO so personally, I think SVO is the way to go. It has
better energy density than ethanol, the flip side of course is that it
has a very high and variable gel temperature. But an engine designs
specifically for SVO _can_ design around this problems, and would
still accept biodiesel and pump-diesel easily. kerosene.... once in a
while. But not recommended.

Germany has a national fuel standard for SVO, and Elsbett has done
extensive work in solving injector coking problems associated with
SVO. So with SVO the engine is heavier, but offset by lower fuel
load, and a slightly shorter TBO, but given the price of 100LL, the
shorter TBO is offset by the fuel savings. Fuel availability would
actually be easier logistically speaking than the current system, once
it is adopted.

The only issue, is that the _only_ company to design an engine
specifically for SVO at this point is Elsbett. There are dozens of
kludges being sold for cars, but no ground-up designs. Funny that
people go to all the trouble of innovating a new engine, and don't
innovate where the fuel is concerned.

-Matt

[clare at snyder dot ontario dot canada]

On Tue, 20 May 2008 15:49:09 +0000, jan olieslagers
> wrote:

>stol schreef:
>>they are able to purchase 10,000 gallons of jet at about half the cost of diesel
>
>????!!!! In what part of the world is Jet A1 cheaper than (uncoloured)
>diesel ????
>
Stale dated jet A is often available at a discount.Apparently.
** Posted from http://www.teranews.com **

[Philippe[_2_]]

Lou wrote:

> Not that I plan to do this but I was wondering, if one was going to
> plan to install a diesel in a homebuilt, what diesel would one put
> in?

Diesel, yes but automotive conversion are at the heavy side.

Some homebuilt wilksch equiped are in progress in France. I know one
Murphy Rebel.

Smaller, the GazAile II but you can't find the small engine outside of
Europe.

Delta hawk V4 if you want bigger is the alternate choice.



--
Volem rien foutre al païs!
Philippe Vessaire Ò¿Ó¬
** Posted from http://www.teranews.com **

[Bill Daniels]

"Lou" > wrote in message
...
> Not that I plan to do this but I was wondering, if one was going to
> plan to install a diesel in a homebuilt, what diesel would one put
> in?
> Lou

FWIW, I'm heading down to the hangar this morning to work on a 10 liter
Cummins 360HP 2100RPM aviation turbo diesel. Of course, we leave the
engine on the ground while using it to launch gliders.