Cessna Anticipates AvGas Demise

"Larry Dighera" wrote in message ...

CESSNA TO OFFER DIESEL SKYHAWK
(http://www.avweb.com/eletter/archive...ll.html#196294)
Cessna will offer the 172S Skyhawk with a Thielert turbo diesel engine
with deliveries to start in mid-2008. In an announcement at AOPA Expo
in Hartford, Conn., Cessna officials said the decision to offer the
diesel came after extensive market surveys and flight testing. "The
Skyhawk is already the best-selling, most-flown airplane ever with
more than 43,000 delivered and this option further expands the market
due to the worldwide availability of Jet A fuel," said John Doman,
Cessna vice president of propeller aircraft sales. Cessna will install
the engines at its Independence, Kan., factory under the supplementary
type certificate already held by Thielert.


Yup, gotta pay for the new improved NAS.
JetA power GA aircraft are going to pay more taxes per gallon than the 100LL drivers, so UnkaSam wants more JetA
sales...

"Larry Dighera" wrote in message news
On Sat, 06 Oct 2007 14:49:21 -0000, wrote in
.com:

Higher compression buns more of the
fuel and captures more of the thermal expansion in the form of
mechanical piston energy. Basic physics.

Diesel engines have a longer TBO than gasoline engines also, don't
they? Given the higher temperatures and pressures, that seems to fly
in the face of basic physics, but I suppose it's a result of lower RPM
operation.

I think those Theilberts are throw away at 1800 hours or something...

The Thielert also has maintenance drawbacks. We checked
into getting some for our 172s, and to maintain them you need either
to take them to an approved repair facility, or go to Texas and take a
two-week (IIRC) course in their maintenance.

A new engine needs a new skill set, simple as that. You wouldn't give
your car to a mechanic who has only repaired Ford T engines so far and
have him check the electronics, either!

There's no TBO. They call it a TBR, where the whole engine is

And where's the disadvantage? You know exactly what it will cost, and
Thielert even refunds you pro rata, should the the engine not make it to
TBR. A fair deal, I would say.

M wrote:

If you have seen the BSFC numbers of the latest and greatest
automobile gasoline engines, they're really not better than a
IO-520. Why? because it's a lot easier to optimize a gasoline
engine for fuel efficiency when it's operated at a narrow RPM range
with little power variation. Automobile engines achieve good fuel
efficiency through electronic engine control only because it's much
harder to gain good efficiency across a much wider RPM range and
throttle setting. From a thermo efficiency point of view, the
gasoline aircraft engines designed in the 50s are very good, if
they're leaned properly (which can be easily done with good fuel
injection and EGT instrumentation), I doubt they can get much better
in fuel efficiency regardless of what electronic you put on them.


Yes, well aircraft engines have a similar problem in terms of
altitude (I know, you have a mixture control) but was also thinking
beyond just the electronics and the methods of injection to
thinhs like pistons, combustion chambers and cams. Those things
have been addressed on most other engines.

But it really doesn't matter because everyone is moving toward
kerosene regardless. Its just one of the several products (as is
gasoline) of the refining process of crude oil.

Blueskies wrote:

I think those Theilberts are throw away at 1800 hours or something...

You think wrongly. It's 2400.

Dan_Thomas_ wrote

The Thielert also has maintenance drawbacks. We checked
into getting some for our 172s, and to maintain them you need either
to take them to an approved repair facility, or go to Texas and take a
two-week (IIRC) course in their maintenance. And buy a bunch of
expensive tools. Any major repairs requires a removal of the engine
and sending it to the approved repair people. Can't take the head off,
for instance, and re-ring a piston or do the valves.
There's no TBO. They call it a TBR, where the whole engine is
replaced with a new one. I can't put my finger on the time but I think
it's around 2400 hours.

Everything but the TBR may be nearly a non issue, if the Thielert has the
kind of no mess reliability I have grown to expect from most diesels. Re
ringing and doing valves are things that an air cooled engine may need
often, but a diesel will probably not need until it is replaced.

Only time will tell how they hold up, once they get into the field with
sufficient numbers. I have a feeling they will be impressive.

I also suspect that the TBR thing could change, also. The factory probably
is going to get all of those replaced engines into their shop, and do a
complete tear-down, and inspection and measurement of every part in the
engine, to get a feel for areas that may need improvement, or possibly could
be made lighter.

I look forward to seeing many Thielerts in the air, and hopefully someone
else will get a product into the air, also. The jet fuel burning IC engine
is GA's best hope for the little guy, IMHO.
--
Jim in NC

wrote:
On Oct 6, 11:24 am, Matt Whiting wrote:
The penalty you pay with diesels is they also tend to be a fair bit
heavier for the same power output.

The Thielert also has maintenance drawbacks. We checked
into getting some for our 172s, and to maintain them you need either
to take them to an approved repair facility, or go to Texas and take a
two-week (IIRC) course in their maintenance. And buy a bunch of
expensive tools. Any major repairs requires a removal of the engine
and sending it to the approved repair people. Can't take the head off,
for instance, and re-ring a piston or do the valves.
There's no TBO. They call it a TBR, where the whole engine is
replaced with a new one. I can't put my finger on the time but I think
it's around 2400 hours.

Dan


Yes, I'd heard that disadvantage also. However, if Cessna starts OEMing
the engine, I suspect it will become a lot easier to get it repaired.
However, if you are in Last Chance, NV, good luck.

Matt

Morgans wrote:
Dan_Thomas_ wrote

The Thielert also has maintenance drawbacks. We checked
into getting some for our 172s, and to maintain them you need either
to take them to an approved repair facility, or go to Texas and take a
two-week (IIRC) course in their maintenance. And buy a bunch of
expensive tools. Any major repairs requires a removal of the engine
and sending it to the approved repair people. Can't take the head off,
for instance, and re-ring a piston or do the valves.
There's no TBO. They call it a TBR, where the whole engine is
replaced with a new one. I can't put my finger on the time but I think
it's around 2400 hours.

Everything but the TBR may be nearly a non issue, if the Thielert has the
kind of no mess reliability I have grown to expect from most diesels. Re
ringing and doing valves are things that an air cooled engine may need
often, but a diesel will probably not need until it is replaced.

Only time will tell how they hold up, once they get into the field with
sufficient numbers. I have a feeling they will be impressive.

I also suspect that the TBR thing could change, also. The factory probably
is going to get all of those replaced engines into their shop, and do a
complete tear-down, and inspection and measurement of every part in the
engine, to get a feel for areas that may need improvement, or possibly could
be made lighter.

I look forward to seeing many Thielerts in the air, and hopefully someone
else will get a product into the air, also. The jet fuel burning IC engine
is GA's best hope for the little guy, IMHO.

Yes, this may be the case, however the TBR has to get closer to 4,000
hours than to 2,400. Most auto and truck diesels will last at least
twice as long as similar size gas engines, so with Lycs and Contis
lasting 2,000 hours fairly routinely, the Thielert needs to at least
double that ... unless the replacement cost is equivalent to an overhaul
of a Lyc or Conti.

Matt

On Sat, 6 Oct 2007 16:42:47 -0400, "Morgans"
wrote in :

Re ringing and doing valves are things that an air cooled engine may need
often, but a diesel will probably not need until it is replaced.

So the diesel is liquid cooled?

Larry Dighera wrote:

Re ringing and doing valves are things that an air cooled engine may need
often, but a diesel will probably not need until it is replaced.

So the diesel is liquid cooled?

http://www.centurion-engines.com/

It's liquid cooled, so no discussion about shock cooling anymore.
It's fully FADEC controlled, so no overheating possible.
It's geared, so a prop strike doesn't affect the engine.
It's fully FADEC controlled, so always best prop pitch to the chosen
power setting.
and and and... in short, everything I would expect from a modern engine.