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Rotax RPMs



 
 
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  #1  
Old November 29th 07, 09:47 PM posted to rec.aviation.piloting
Paul Tomblin
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Posts: 690
Default Rotax RPMs

In a previous article, said:
A quick Google search yielded this info on the engine used in the
Remos:

http://www.rotaxservice.com/rotax_en...ax_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
  #2  
Old November 29th 07, 10:31 PM posted to rec.aviation.piloting
Maxwell
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Posts: 1,116
Default Rotax RPMs


"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_en...ax_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.


  #3  
Old November 30th 07, 02:41 AM posted to rec.aviation.piloting
[email protected]
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Posts: 373
Default Rotax RPMs

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?
  #5  
Old November 30th 07, 12:12 PM posted to rec.aviation.piloting
news.verizon.net[_2_]
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Posts: 32
Default Rotax RPMs

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?


  #6  
Old November 30th 07, 12:33 PM posted to rec.aviation.piloting
Matt Whiting
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Posts: 2,232
Default Rotax RPMs

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


Quicker restart.
  #7  
Old November 30th 07, 06:58 PM posted to rec.aviation.piloting
Stefan
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Posts: 578
Default Rotax RPMs

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.
  #8  
Old November 30th 07, 10:49 PM posted to rec.aviation.piloting
Maxwell
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Posts: 1,116
Default Rotax RPMs


"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.


  #9  
Old November 30th 07, 04:41 PM posted to rec.aviation.piloting
[email protected]
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Posts: 1,130
Default Rotax RPMs

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
  #10  
Old November 30th 07, 07:02 PM posted to rec.aviation.piloting
Bertie the Bunyip[_19_]
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Posts: 3,851
Default Rotax RPMs

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
 




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