Rotax RPMs

[Paul Tomblin]

I'm reading the specs for the Remos G-3. Looks like a nice plane. But
one thing that gobsmacked me was the note that "Max endurance: 6hrs at
4300rpm". Does it really run at 4300rpm? Is the prop geared down from
that? I mean, I normally fly a Lance with a 300hp IO-540, and it's pretty
damn noisy at 2650 rpm. I shudder to think what a prop spinning at 4300
rpm sounds like.

--
Paul Tomblin > http://blog.xcski.com/
"All life is transitory. A dream. We all come together in the same place at
the end of time. If I don't see you again here, I will see you in a little
while in the place where no shadows fall." - Delenn

[Jim Stewart]

Paul Tomblin wrote:
> I'm reading the specs for the Remos G-3. Looks like a nice plane. But
> one thing that gobsmacked me was the note that "Max endurance: 6hrs at
> 4300rpm". Does it really run at 4300rpm? Is the prop geared down from
> that? I mean, I normally fly a Lance with a 300hp IO-540, and it's pretty
> damn noisy at 2650 rpm. I shudder to think what a prop spinning at 4300
> rpm sounds like.

I believe all Rotax 912's have a prop
gear reduction, with ratios of 2:1,
2.24:1 and 2.58:1 available. I couldn't
see any specs for what the G-3 comes
with, but would bet it was either the
2.24 or 2.58.

[Gig 601XL Builder]

Paul Tomblin wrote:
> I'm reading the specs for the Remos G-3. Looks like a nice plane.
> But one thing that gobsmacked me was the note that "Max endurance:
> 6hrs at 4300rpm". Does it really run at 4300rpm?

Yes and yes.

[[email protected]]

A quick Google search yielded this info on the engine used in the
Remos:

http://www.rotaxservice.com/rotax_engines/rotax_912ULSs.htm

[Paul Tomblin]

In a previous article, said:
>A quick Google search yielded this info on the engine used in the
>Remos:
>
>http://www.rotaxservice.com/rotax_engines/rotax_912ULSs.htm

Ok, I'm a little embarassed that I couldn't find that info myself.

Is a reduction gearbox seen as a reliability problem, or isn't that such a
big deal any more?

--
Paul Tomblin > http://blog.xcski.com/
"Oh my G'Quan, they killed Koshi!" - Citizen G'kyle, Babylon Park

[Maxwell]

"Paul Tomblin" > wrote in message
...
> In a previous article, said:
>>A quick Google search yielded this info on the engine used in the
>>Remos:
>>
>>http://www.rotaxservice.com/rotax_engines/rotax_912ULSs.htm
>
> Ok, I'm a little embarassed that I couldn't find that info myself.
>
> Is a reduction gearbox seen as a reliability problem, or isn't that such a
> big deal any more?
>
> --


I haven't flown one, so I can't be certain, but I'm guessing it would at
least seriously hamper the engines ability to windmill during a temporary
fuel starvation, or carb ice situation.

[Phil]

On Nov 29, 3:47 pm, (Paul Tomblin) wrote:
> In a previous article, said:
>
> >A quick Google search yielded this info on the engine used in the
> >Remos:
>
> >http://www.rotaxservice.com/rotax_engines/rotax_912ULSs.htm
>
> Ok, I'm a little embarassed that I couldn't find that info myself.
>
> Is a reduction gearbox seen as a reliability problem, or isn't that such a
> big deal any more?
>
> --
> Paul Tomblin /
> "Oh my G'Quan, they killed Koshi!" - Citizen G'kyle, Babylon Park

I don't think anyone really knows the reliability of this engine and
gearbox. It hasn't been in service long enough. I have been training
behind one in a Flight Design CT, and it is not a noisy engine at
all. When I watch a CT take off I am really struck by how quiet the
airplane is. Also the engine has altitude-compensating carbs, so
there is no mixture to mess with. In flight the engine is very
responsive and smooth. I know a lot of people are put off by the high
rpms, but if the engine is designed to run at those speeds I am not
sure that is really a problem.

My one comment on the gearbox is it has a harmonic resonance vibration
at about 1800-1900 rpm (taxi speeds) which is very noticeable. I try
to avoid that, and bump it up to about 2000, and it's nice and smooth
there.

Phil

[Bertie the Bunyip[_19_]]

Phil > wrote in
:

> On Nov 29, 3:47 pm, (Paul Tomblin) wrote:
>> In a previous article, said:
>>
>> >A quick Google search yielded this info on the engine used in the
>> >Remos:
>>
>> >http://www.rotaxservice.com/rotax_engines/rotax_912ULSs.htm
>>
>> Ok, I'm a little embarassed that I couldn't find that info myself.
>>
>> Is a reduction gearbox seen as a reliability problem, or isn't that
>> such a big deal any more?
>>
>> --
>> Paul Tomblin /
>> "Oh my G'Quan, they killed Koshi!" - Citizen G'kyle, Babylon Park
>
> I don't think anyone really knows the reliability of this engine and
> gearbox. It hasn't been in service long enough.

It's been around almost twenty years now!


Bertie

[Jim Stewart]

Phil wrote:
> On Nov 29, 3:47 pm, (Paul Tomblin) wrote:
>> In a previous article, said:
>>
>>> A quick Google search yielded this info on the engine used in the
>>> Remos:
>>> http://www.rotaxservice.com/rotax_engines/rotax_912ULSs.htm
>> Ok, I'm a little embarassed that I couldn't find that info myself.
>>
>> Is a reduction gearbox seen as a reliability problem, or isn't that such a
>> big deal any more?
>>
>> --
>> Paul Tomblin /
>> "Oh my G'Quan, they killed Koshi!" - Citizen G'kyle, Babylon Park
>
> I don't think anyone really knows the reliability of this engine and
> gearbox. It hasn't been in service long enough. I have been training
> behind one in a Flight Design CT, and it is not a noisy engine at
> all. When I watch a CT take off I am really struck by how quiet the
> airplane is. Also the engine has altitude-compensating carbs, so
> there is no mixture to mess with. In flight the engine is very
> responsive and smooth. I know a lot of people are put off by the high
> rpms, but if the engine is designed to run at those speeds I am not
> sure that is really a problem.

I'd like to get some more information on this.
The Rotax 912 has been in production since
around 1992 and the 912ULS since 1999. Should
be information somewhere.

I've heard that thousands of them have been
sold for drones and unmanned aircraft of various
types.

> My one comment on the gearbox is it has a harmonic resonance vibration
> at about 1800-1900 rpm (taxi speeds) which is very noticeable. I try
> to avoid that, and bump it up to about 2000, and it's nice and smooth
> there.

Yup. That's why there's a yellow band on
the tach. I try to never run my engine there.

[Bertie the Bunyip[_19_]]

Jim Stewart > wrote in
:

> Phil wrote:
>> On Nov 29, 3:47 pm, (Paul Tomblin) wrote:
>>> In a previous article, said:
>>>
>>>> A quick Google search yielded this info on the engine used in the
>>>> Remos:
>>>> http://www.rotaxservice.com/rotax_engines/rotax_912ULSs.htm
>>> Ok, I'm a little embarassed that I couldn't find that info myself.
>>>
>>> Is a reduction gearbox seen as a reliability problem, or isn't that
>>> such a big deal any more?
>>>
>>> --
>>> Paul Tomblin /
>>> "Oh my G'Quan, they killed Koshi!" - Citizen G'kyle, Babylon Park
>>
>> I don't think anyone really knows the reliability of this engine and
>> gearbox. It hasn't been in service long enough. I have been
>> training behind one in a Flight Design CT, and it is not a noisy
>> engine at all. When I watch a CT take off I am really struck by how
>> quiet the airplane is. Also the engine has altitude-compensating
>> carbs, so there is no mixture to mess with. In flight the engine is
>> very responsive and smooth. I know a lot of people are put off by
>> the high rpms, but if the engine is designed to run at those speeds I
>> am not sure that is really a problem.
>
> I'd like to get some more information on this.
> The Rotax 912 has been in production since
> around 1992 and the 912ULS since 1999. Should
> be information somewhere.
>
> I've heard that thousands of them have been
> sold for drones and unmanned aircraft of various
> types.
>

There's been quite a lot of them on certified airplanes in Europe as
well as thousands on homebuilts round the world for quite some time.

It's pretty easy to check how well they work in the real world. Look for
airplanes for sale with the engine installed. If most of the airplanes
with around 1,000 hours on them have engines with about 500 hours on
them, well, you have your answer. But afaik, they work well and last a
long time.

Bertie

[Ron Wanttaja]

On Thu, 29 Nov 2007 21:47:23 +0000 (UTC), (Paul
Tomblin) wrote:

> In a previous article, said:
> >A quick Google search yielded this info on the engine used in the
> >Remos:
> >
> >http://www.rotaxservice.com/rotax_engines/rotax_912ULSs.htm
>
> Ok, I'm a little embarassed that I couldn't find that info myself.
>
> Is a reduction gearbox seen as a reliability problem, or isn't that such a
> big deal any more?

I've run some accident analyses of homebuilts using alternate engines. Out of
~95 homebuilts with Rotax four-strokes that had accidents during 1998-2004,
about 14% of them were due to some sort of mechanical problem with the
powerplant. None of them were due to failures of the gearbox.

BTW, that 14% is about the same as conventional engines....

Ron Wanttaja

[[email protected]]

> I haven't flown one, so I can't be certain, but I'm guessing it would at
> least seriously hamper the engines ability to windmill during a temporary
> fuel starvation, or carb ice situation.

I've never thought of that.

Does anyone with Rotax flight experience know the answer to that?

[Kyle Boatright]

"Bertie the Bunyip" > wrote in message
.. .
> Phil > wrote in
> :
>
>> On Nov 29, 3:47 pm, (Paul Tomblin) wrote:
>>> In a previous article, said:
>>>
>>> >A quick Google search yielded this info on the engine used in the
>>> >Remos:
>>>
>>> >http://www.rotaxservice.com/rotax_engines/rotax_912ULSs.htm
>>>
>>> Ok, I'm a little embarassed that I couldn't find that info myself.
>>>
>>> Is a reduction gearbox seen as a reliability problem, or isn't that
>>> such a big deal any more?
>>>
>>> --
>>> Paul Tomblin /
>>> "Oh my G'Quan, they killed Koshi!" - Citizen G'kyle, Babylon Park
>>
>> I don't think anyone really knows the reliability of this engine and
>> gearbox. It hasn't been in service long enough.
>
> It's been around almost twenty years now!
>
>
> Bertie

Yeah, but other than that 20 year history, there is very little data. ;-)

KB

[Jim Stewart]

wrote:
>>I haven't flown one, so I can't be certain, but I'm guessing it would at
>>least seriously hamper the engines ability to windmill during a temporary
>>fuel starvation, or carb ice situation.
>
>
> I've never thought of that.
>
> Does anyone with Rotax flight experience know the answer to that?

We had the engine stop during a power-off
stall. The idle was set too low. It didn't
start turning again until we started it.

I don't know what would happen at 120 knots,
but I wouldn't count on it windmilling.

[news.verizon.net[_2_]]

Why do you want it to windmill? there is no vacuum system.
> wrote in message
...
>> I haven't flown one, so I can't be certain, but I'm guessing it would at
>> least seriously hamper the engines ability to windmill during a temporary
>> fuel starvation, or carb ice situation.
>
> I've never thought of that.
>
> Does anyone with Rotax flight experience know the answer to that?

[Matt Whiting]

news.verizon.net wrote:
> Why do you want it to windmill? there is no vacuum system.

Quicker restart.

[Thomas Borchert]

Paul,

> Does it really run at 4300rpm?
>

Yes (no offense, but in what hole have you been hiding all those years?
;-))

It is geared down. It is a very, very quiet engine, much quieter than
any Lycosaurus or TCM. Thanks to water cooling which also ends the
shock cooling debate. Welcome to 1990s technology.

--
Thomas Borchert (EDDH)

[Thomas Borchert]

Phil,

> I don't think anyone really knows the reliability of this engine and
> gearbox. It hasn't been in service long enough.
>

Are you kidding? These have been in service in huge numbers for well
over a decade. The original Diamond Katana was introduced with them.
These engines are VERY proven. It may have happened outside the US (and
thus outside the advertising range of "Flying" and thus outside their
editorial coverage), but trust me, it still happened.

--
Thomas Borchert (EDDH)

[Mike Proctor]

>Does it really run at 4300rpm?

You can run it over 5,000 for 5 minutes or so. I usually run about
4,800 in the Evektor Sportstar I fly.

[Bertie the Bunyip[_19_]]

Thomas Borchert > wrote in
:

> Paul,
>
>> Does it really run at 4300rpm?
>>
>
> Yes (no offense, but in what hole have you been hiding all those years?
> ;-))
>
> It is geared down. It is a very, very quiet engine, much quieter than
> any Lycosaurus or TCM. Thanks to water cooling which also ends the
> shock cooling debate. Welcome to 1990s technology.


Actually,there's nothing on it that wasn't on some airplane engine by the
end of the first world war.
They're good engines, but I wouldn;t have one.




Bertie
>

[Bertie the Bunyip[_19_]]

"Kyle Boatright" > wrote in
:

>
> "Bertie the Bunyip" > wrote in message
> .. .
>> Phil > wrote in
>> news:354adc88-de99-4b4d-bbc4-

>> :
>>
>>> On Nov 29, 3:47 pm, (Paul Tomblin) wrote:
>>>> In a previous article, said:
>>>>
>>>> >A quick Google search yielded this info on the engine used in the
>>>> >Remos:
>>>>
>>>> >http://www.rotaxservice.com/rotax_engines/rotax_912ULSs.htm
>>>>
>>>> Ok, I'm a little embarassed that I couldn't find that info myself.
>>>>
>>>> Is a reduction gearbox seen as a reliability problem, or isn't that
>>>> such a big deal any more?
>>>>
>>>> --
>>>> Paul Tomblin /
>>>> "Oh my G'Quan, they killed Koshi!" - Citizen G'kyle, Babylon Park
>>>
>>> I don't think anyone really knows the reliability of this engine and
>>> gearbox. It hasn't been in service long enough.
>>
>> It's been around almost twenty years now!
>>
>>
>> Bertie
>
> Yeah, but other than that 20 year history, there is very little data.
> ;-)
>


There's loads of data..


Bertie

[[email protected]]

On Nov 29, 3:31 pm, "Maxwell" > wrote:

> I haven't flown one, so I can't be certain, but I'm guessing it would at
> least seriously hamper the engines ability to windmill during a temporary
> fuel starvation, or carb ice situation.

If a Lyc or Continental dies due to carb ice, it isn't going to
restart either. It needs air and fuel to generate heat to get the ice
out, and a pilot who lets things deteriorate until the thing is dead
is faced with a forced landing whether it's a direct-drive engine or a
geared engine.
Continental has built geared engines: The GO-300, GO-480, the
Tiara (not too successful), and there are many geared radials. Most
have some RPM range where they're not comfortable, and some direct-
drive setups have the same due to prop resonance. The Cherokee 180
was one of them. There's a yellow arc on the tach: pass through it,
don't linger there. All will be well.
Geared engines are more efficient in terms of weight/HP ratio.
HP is a function of torque times RPM, so raising RPM gets more jam for
a small weight increase in the form of a reduction of some sort.
Gears, V-belts, timing belts, chains; they've all been employed. In
some engines it improves safety by taking the thrust and gyroscopic
forces off the crankshaft and putting them onto something more
suitable.
If it hadn't been for geared engines we wouldn't have had the
P-51, P-40, Spitfire, P-38, Lancaster, and many more. On the other
hand, the other side wouldn't have been such a threat.

Dan

[Stefan]

Matt Whiting schrieb:

>> Why do you want it to windmill? there is no vacuum system.

> Quicker restart.

In the only situation that I can think of in which a quick engine
restart may matter, you really wouldn't want to dive for windmill.
Besides, using the starter yields the desired result at least as quickly.

[Bertie the Bunyip[_19_]]

wrote in
:

> On Nov 29, 3:31 pm, "Maxwell" > wrote:
>
>> I haven't flown one, so I can't be certain, but I'm guessing it would
>> at least seriously hamper the engines ability to windmill during a
>> temporary fuel starvation, or carb ice situation.
>
> If a Lyc or Continental dies due to carb ice, it isn't going to
> restart either. It needs air and fuel to generate heat to get the ice
> out, and a pilot who lets things deteriorate until the thing is dead
> is faced with a forced landing whether it's a direct-drive engine or a
> geared engine.
> Continental has built geared engines: The GO-300, GO-480, the
> Tiara (not too successful), and there are many geared radials. Most
> have some RPM range where they're not comfortable, and some direct-
> drive setups have the same due to prop resonance. The Cherokee 180
> was one of them. There's a yellow arc on the tach: pass through it,
> don't linger there. All will be well.
> Geared engines are more efficient in terms of weight/HP ratio.
> HP is a function of torque times RPM, so raising RPM gets more jam for
> a small weight increase in the form of a reduction of some sort.
> Gears, V-belts, timing belts, chains; they've all been employed. In
> some engines it improves safety by taking the thrust and gyroscopic
> forces off the crankshaft and putting them onto something more
> suitable.
> If it hadn't been for geared engines we wouldn't have had the
> P-51, P-40, Spitfire, P-38, Lancaster, and many more. On the other
> hand, the other side wouldn't have been such a threat.
>
> Dan
>
Again, it goes back much further than that. Hisso had a lot of success with
their geared version of the 8VA back in '17...

Bertie

[Phil]

On Nov 30, 9:34 am, Thomas Borchert >
wrote:
> Phil,
>
> > I don't think anyone really knows the reliability of this engine and
> > gearbox. It hasn't been in service long enough.
>
> Are you kidding? These have been in service in huge numbers for well
> over a decade. The original Diamond Katana was introduced with them.
> These engines are VERY proven. It may have happened outside the US (and
> thus outside the advertising range of "Flying" and thus outside their
> editorial coverage), but trust me, it still happened.
>
> --
> Thomas Borchert (EDDH)

I thought the 912 was fairly new. I can't find a history of the
engine. Anybody know when they first came out?

Phil

[Bertie the Bunyip[_19_]]

Phil > wrote in news:e2b63a34-2301-48d0-a78b-
:

> On Nov 30, 9:34 am, Thomas Borchert >
> wrote:
>> Phil,
>>
>> > I don't think anyone really knows the reliability of this engine and
>> > gearbox. It hasn't been in service long enough.
>>
>> Are you kidding? These have been in service in huge numbers for well
>> over a decade. The original Diamond Katana was introduced with them.
>> These engines are VERY proven. It may have happened outside the US (and
>> thus outside the advertising range of "Flying" and thus outside their
>> editorial coverage), but trust me, it still happened.
>>
>> --
>> Thomas Borchert (EDDH)
>
> I thought the 912 was fairly new. I can't find a history of the
> engine. Anybody know when they first came out?


1987. They gained certification in 1989


Bertie

[Matt Whiting]

Thomas Borchert wrote:
> Paul,
>
>> Does it really run at 4300rpm?
>>
>
> Yes (no offense, but in what hole have you been hiding all those years?
> ;-))
>
> It is geared down. It is a very, very quiet engine, much quieter than
> any Lycosaurus or TCM. Thanks to water cooling which also ends the
> shock cooling debate. Welcome to 1990s technology.
>

Really?

http://www.zenoswarbirdvideos.com/P-51_Variants.html

Seems like water cooling has been around just a little longer than that.

Matt

[Maxwell]

"Stefan" > wrote in message
...
> Matt Whiting schrieb:
>
>>> Why do you want it to windmill? there is no vacuum system.
>
>> Quicker restart.
>
> In the only situation that I can think of in which a quick engine restart
> may matter, you really wouldn't want to dive for windmill. Besides, using
> the starter yields the desired result at least as quickly.

You don't need to dive on a direct drive, the engine continues to windmill
from the time it stalls. In Cessna's you have to slow to very near stall
speed to actually stop the prop. I would suspect the same for all the
Lycoming and Continental powered aircraft.

[Maxwell]

> wrote in message
...
>
> If a Lyc or Continental dies due to carb ice, it isn't going to
> restart either. It needs air and fuel to generate heat to get the ice
> out, and a pilot who lets things deteriorate until the thing is dead
> is faced with a forced landing whether it's a direct-drive engine or a
> geared engine.

Not true, been there and done it.

[Vaughn Simon]

"Maxwell" > wrote in message
...
>I'm guessing it would at least seriously hamper the engines ability to windmill
>during a temporary fuel starvation, or carb ice situation.

A windmilling propeller significantly increases your sink rate when your
engine stops making noise. Do you really want that? ...or would you rather
have more time to sort things out, and/or more landing options within gliding
range?

I know my choice!

Vaughn


>
>

[[email protected]]

On Nov 30, 12:02 pm, Bertie the Bunyip > wrote:

> Again, it goes back much further than that. Hisso had a lot of success with
> their geared version of the 8VA back in '17...
>
> Bertie

Seems to me the Wright Brothers had chain drives on the 1903
Flyer, too. Can't get too much further back than that, unless we
consider some steam-powered attempts in the late 1800s.

Dan

[[email protected]]

On Nov 30, 3:43 pm, Matt Whiting > wrote:
> Really?
>
> http://www.zenoswarbirdvideos.com/P-51_Variants.html
>
> Seems like water cooling has been around just a little longer than that.
>
> Matt

Much, much longer than that. Here's a quote from
http://www.allstar.fiu.edu/AERO/Propulsion1.htm

"The problem involving water cooled engines is the excess
drag and weight that would be added to the plane thereby having a
significant influence in aircraft performance. By 1908 this
degradation of aircraft performance due to liquid-cooled systems was
noticed and air-cooled engines were first introduced. The savings in
weight were substantial. The air-cooled engine weight (on average) was
between 30% and 40% of the weight of the liquid-cooled engine."

[Bertie the Bunyip[_19_]]

wrote in
:

> On Nov 30, 12:02 pm, Bertie the Bunyip > wrote:
>
>> Again, it goes back much further than that. Hisso had a lot of
>> success with their geared version of the 8VA back in '17...
>>
>> Bertie
>
> Seems to me the Wright Brothers had chain drives on the 1903
> Flyer, too. Can't get too much further back than that, unless we
> consider some steam-powered attempts in the late 1800s.

Absolutely true!

Come to think of it, it had a water cooled head as well.



Bertie

[[email protected]]

On Nov 30, 3:54 pm, "Maxwell" > wrote:
> > wrote in message
>
> ...
>
>
>
> > If a Lyc or Continental dies due to carb ice, it isn't going to
> > restart either. It needs air and fuel to generate heat to get the ice
> > out, and a pilot who lets things deteriorate until the thing is dead
> > is faced with a forced landing whether it's a direct-drive engine or a
> > geared engine.
>
> Not true, been there and done it.

There's a shroud around some part of the exhaust system, and air
is forced through it to accumulate heat from the hot exhaust. If the
throttle is closed or nearly so and the aircraft is gliding, the
exhaust system cools off quickly because it's made from very light
material of little mass and large area. If ice forms in the carb, less
fuel and air reach the cylinders, things cool off more, and soon
enough, if the pilot isn't paying attention or doesn't understand,
it's all over.
There have been numerous accidents because the engine began to
lose power so carb heat was applied, it ran rougher so the pilots shut
the heat off, and after the thing died altogether they pulled the heat
on again but it was too late. It reflects a lack of training: the
engine will run rougher both because the mixture gets richer and it's
getting liquid water into the cylinders, which tends to annoy it some.
Applying the heat and leave it until the thing sorts itself out is the
only solution. And go to a higher power setting; partial power might
just get more ice forming. There have been cases where the throttle
froze solid and would not move.
Lycomings have the carb bolted to the oil sump and the hot
oil warms the carb body so that the carb heat system around the
exhaust is really small. In cooler weather the oil may not do the job
and ice will form, especially early in the flight when the oil isn't
too hot. Continentals don't have the carb bolted to such warm stuff
and they'll ice up much quicker.

Dan

[Stefan]

Bertie the Bunyip schrieb:

>> Seems to me the Wright Brothers had chain drives on the 1903
>> Flyer

> Come to think of it, it had a water cooled head as well.

But it wasn't exactly reliable...

[Bertie the Bunyip[_19_]]

Stefan > wrote in news:44133$47513f2d$d9a270c7
:

> Bertie the Bunyip schrieb:
>
>>> Seems to me the Wright Brothers had chain drives on the 1903
>>> Flyer
>
>> Come to think of it, it had a water cooled head as well.
>
> But it wasn't exactly reliable...
>

Sure it was. It did the job it was asked to do. That's the defintion of
reliable.



Bertie

[Matt Whiting]

wrote:
> On Nov 30, 3:43 pm, Matt Whiting > wrote:
>> Really?
>>
>> http://www.zenoswarbirdvideos.com/P-51_Variants.html
>>
>> Seems like water cooling has been around just a little longer than that.
>>
>> Matt
>
> Much, much longer than that. Here's a quote from
> http://www.allstar.fiu.edu/AERO/Propulsion1.htm
>
> "The problem involving water cooled engines is the excess
> drag and weight that would be added to the plane thereby having a
> significant influence in aircraft performance. By 1908 this
> degradation of aircraft performance due to liquid-cooled systems was
> noticed and air-cooled engines were first introduced. The savings in
> weight were substantial. The air-cooled engine weight (on average) was
> between 30% and 40% of the weight of the liquid-cooled engine."

So who wants to buy a Rotax with early 1900s technology when you can
have the newer air cooled technology! :-)

Matt

[Maxwell]

> wrote in message
...

>
> There's a shroud around some part of the exhaust system, and air
> is forced through it to accumulate heat from the hot exhaust. If the
> throttle is closed or nearly so and the aircraft is gliding, the
> exhaust system cools off quickly because it's made from very light
> material of little mass and large area. If ice forms in the carb, less
> fuel and air reach the cylinders, things cool off more, and soon
> enough, if the pilot isn't paying attention or doesn't understand,
> it's all over.
> There have been numerous accidents because the engine began to
> lose power so carb heat was applied, it ran rougher so the pilots shut
> the heat off, and after the thing died altogether they pulled the heat
> on again but it was too late. It reflects a lack of training: the
> engine will run rougher both because the mixture gets richer and it's
> getting liquid water into the cylinders, which tends to annoy it some.
> Applying the heat and leave it until the thing sorts itself out is the
> only solution. And go to a higher power setting; partial power might
> just get more ice forming. There have been cases where the throttle
> froze solid and would not move.
> Lycomings have the carb bolted to the oil sump and the hot
> oil warms the carb body so that the carb heat system around the
> exhaust is really small. In cooler weather the oil may not do the job
> and ice will form, especially early in the flight when the oil isn't
> too hot. Continentals don't have the carb bolted to such warm stuff
> and they'll ice up much quicker.
>

I don't care if you write a novel and include cad drawing. It's still not
true. YMMV

[[email protected]]

On Dec 1, 7:58 am, "Maxwell" > wrote:

> I don't care if you write a novel and include cad drawing. It's still not
> true. YMMV

Maybe you should argue with historical fact instead of novels
or CAD drawings. Might learn something. Here's just one example
from http://www.aopa.org/asf/ntsb/searchResults.cfm?tss=14

MIA07LA028

Narrative Type: NTSB FINAL NARRATIVE (6120.4)
The pilot stated that a few minutes after departing, while at 1,000
feet over the city of Cape Coral, Florida, he said he set the throttle
to a cruise RPM of 2300, and within about a half minute the engine
RPMs dropped to idle RPM. He said he activated the carburetor heat
control and a few minutes later the engine ceased operating. He said
he attempted to restart the engine, but it would not start, so he made
a forced landing on the northbound lanes of a 4-laned street. During
the landing rollout the right wing struck two road signs and the
airplane veered, incurring damage. The 0630, Fort Myers (FMY),
Florida, surface weather observation showed that the visibility was 1
and 3/4 statute miles, and the ceiling as 600 overcast. FAA records
showed that the private-rated pilot/owner of the accident airplane did
not possess an instrument rating. An FAA maintenance inspector
responded to the accident scene, removed the engine cowling, and
conducted an examination of the airplane. No anomalies were noted. In
addition an FAA licensed mechanic conducted a detailed engine
examination under FAA supervision, and no anomalies were noted. Review
of carburetor icing probability charts show that at the time of the
engine failure the flight was operating in conditions conductive to
moderate icing during cruise power settings and serious icing during
glide/descent power settings.

Dan

[Maxwell]

> wrote in message
...
> On Dec 1, 7:58 am, "Maxwell" > wrote:
>
>> I don't care if you write a novel and include cad drawing. It's still not
>> true. YMMV
>
> Maybe you should argue with historical fact instead of novels
> or CAD drawings. Might learn something. Here's just one example
> from http://www.aopa.org/asf/ntsb/searchResults.cfm?tss=14
>
> MIA07LA028
>
> Narrative Type: NTSB FINAL NARRATIVE (6120.4)
> The pilot stated that a few minutes after departing, while at 1,000
snip->

I don't need to research anything Dan, I told you I have experienced it
personally on more than one occasion and found your statement to be false.
Especially in the context that you initially offered it.

Just because your engine has failed completely, and due only to carb ice,
doesn't mean you can't save you bacon with carb heat. Furthermore, a
windmilling engine can be very helpful in supplying the time (and
circulation) required to do so without having to rely on the battery or
starter.

Can I assure everyone that they will ALWAYS be able to clear a frozen carb
with just carb heaT? Hell no. But that has zero to do with the disussion,
WINDMILLING.

[[email protected]]

On Dec 1, 8:49 am, "Maxwell" > wrote:
> > wrote in message
>
> ...> On Dec 1, 7:58 am, "Maxwell" > wrote:
>
> >> I don't care if you write a novel and include cad drawing. It's still not
> >> true. YMMV
>
> > Maybe you should argue with historical fact instead of novels
> > or CAD drawings. Might learn something. Here's just one example
> > from http://www.aopa.org/asf/ntsb/searchResults.cfm?tss=14
>
> > MIA07LA028
>
> > Narrative Type: NTSB FINAL NARRATIVE (6120.4)
> > The pilot stated that a few minutes after departing, while at 1,000
>
> snip->
>
> I don't need to research anything Dan, I told you I have experienced it
> personally on more than one occasion and found your statement to be false.
> Especially in the context that you initially offered it.
>
> Just because your engine has failed completely, and due only to carb ice,
> doesn't mean you can't save you bacon with carb heat. Furthermore, a
> windmilling engine can be very helpful in supplying the time (and
> circulation) required to do so without having to rely on the battery or
> starter.
>
> Can I assure everyone that they will ALWAYS be able to clear a frozen carb
> with just carb heaT? Hell no. But that has zero to do with the disussion,
> WINDMILLING.

So, where do you think the carb heat comes from in a
windmilling engine that has stopped firing because carb ice has
completely iced over the fuel nozzle? Have you ever worked on an
airplane and seen how the carb heat works? Do you think it's electric
or something?

Dan

[Maxwell]

> wrote in message
...
> On Dec 1, 8:49 am, "Maxwell" > wrote:
>>
>> I don't need to research anything Dan, I told you I have experienced it
>> personally on more than one occasion and found your statement to be
>> false.
>> Especially in the context that you initially offered it.
>>
>> Just because your engine has failed completely, and due only to carb ice,
>> doesn't mean you can't save you bacon with carb heat. Furthermore, a
>> windmilling engine can be very helpful in supplying the time (and
>> circulation) required to do so without having to rely on the battery or
>> starter.
>>
>> Can I assure everyone that they will ALWAYS be able to clear a frozen
>> carb
>> with just carb heaT? Hell no. But that has zero to do with the disussion,
>> WINDMILLING.
>
> So, where do you think the carb heat comes from in a
> windmilling engine that has stopped firing because carb ice has
> completely iced over the fuel nozzle? Have you ever worked on an
> airplane and seen how the carb heat works? Do you think it's electric
> or something?
>

You seem to think that within 10 seconds of loosing power from an carb ice
condition, that the engine and heat exchanger on the exhaust have cooled to
the point that it's impossible for them to deice the carb. And the simply is
not true, and I have proven that many times while actually flying in winter
conditions.

[[email protected]]

On Dec 1, 1:50 pm, "Maxwell" > wrote:

>
> You seem to think that within 10 seconds of loosing power from an carb ice
> condition, that the engine and heat exchanger on the exhaust have cooled to
> the point that it's impossible for them to deice the carb. And the simply is
> not true, and I have proven that many times while actually flying in winter
> conditions.

You had claimed that you had had a *complete* engine failure. It is
obvious that you did not, and that the thing was still firing enough
to generate some heat. Here's the quote:

> > If a Lyc or Continental dies due to carb ice, it isn't going to
> > restart either. It needs air and fuel to generate heat to get the ice
> > out, and a pilot who lets things deteriorate until the thing is dead
> > is faced with a forced landing whether it's a direct-drive engine or a
> > geared engine.

> Not true, been there and done it.

Ten seconds is a long time. I am an aircraft mechanic as well as
a CPL and CFI, and I work on those exhaust systems from which the carb
heat is taken. A 172's heat muff is a small open-faced shroud around
one exhaust riser, and collects very little heat. The Lycoming doesn't
need so much, with its carb heated by the hot oil sump. Other
aircraft, especially Continental-powered airplanes, have a shroud
around the muffler; a 150 has two small, stainless-steel mufflers, one
of which supplies carb heat. That muffler is about 14" long and four
inches in diameter and weighs about two pounds. The metal is no more
than .025" thick. Air is passed around it under the shroud all the
time to keep it cool, and when carb heat is applied, that air is
directed to the carb intake insted of being dumped overboard.
If the engine stops firing altogether due to carb ice, that
muffler will cool off so fast it's not funny. It will aready have
cooled greatly if tghe engine was idling for any length of time, and
if carb ice was forming the power loss would just cool it off further.
These aren't automobile exhaust systems with heavy cast manifolds,
where the pipe is minimum .063" and the mufflers are several layers of
sheet steel.
The accident database I pointed out earlier is full of
needless forced landings just because carb ice wasn't understood. So
many folks think it's a threat only in the winter and can't figure out
why it's happening in the summer. It's been experienced at temps as
high as +40°C (100F), with suffficiently high dewpoints. It can happen
down to -20°C, below which all supercooled atmospheric water has
frozen, but some folks have gotten themselves some carb ice by using
the carb heat and melting that moisture, and having it refreeze in the
carb or intake runners. We operate in temps as low as -25°C here but
give up after that. Some commercial operators keep flying down to -40
or lower. The worst icing is found between 0 and +15°C
http://ibis.experimentals.de/images/carbicingfromcaassl14.gif

Dan

Dan

[Maxwell]

There you go Hemmingway, write us another novel. I don't care, post your SAT
scores. It doesn't change the fact.

I have been there and done, and more than once.