Rotax RPMs

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

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.

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.

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

http://www.rotaxservice.com/rotax_en...ax_912ULSs.htm

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

"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.

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?

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.

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?

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