Light twins not using contra-rotating propellers

Mark Levin wrote:
Hello,

As was pointed out to me the Beechcraft Baron does not use contra-rotating
propellers. A bit of research showed me that most U.S. built light twins do
not use them either.

One twin that I have experience with, the Seminole, does have counter
rotating props.

"Mark Levin" wrote in message
...

On 30-Nov-2006, RomeoMike wrote:

One twin that I have experience with, the Seminole, does have counter
rotating props.

Out of curiosity does this have a marked effect on it's operation compared
with the other twins you've flown?
Any procedures different because of it?

Most aircraft engines rotate counter clockwise as you are in front of the
aircraft looking at it. It is desirable for single engine operations, the
downward stroke of the propeller be next to the fuselage. For this the
right engine would need to rotate clockwise (as looking back from the
front). Most twins don't do this and right engine only handling become
"difficult".

Danny Dot


ml

Mark Levin wrote:


Out of curiosity does this have a marked effect on it's operation compared
with the other twins you've flown?
Any procedures different because of it?

My solo multi time is limited to light twins. The most noticeable
difference in "normal" flight is the decrease or absence of left turning
tendency in high AOA situations such as TO and climb because P factor
and torque from one engine cancels those factors from the other engine.
The other main difference with counter rotating props, of course, is the
lack of a critical engine. In other words, no more asymmetrical thrust
is produced if one engine fails compared to the other.Therefore, turning
tendencies are less when practicing critical engine out procedures (or
Vmc demos) than they would be in the conventional set up. I wouldn't say
that any procedures are different. One still practices the same things.
There is still a lot of asymmetric thrust in engine out scenarios. A
multi instructor once told me that a twin is like any other airplane,
but when it loses an engine it becomes a sled. I would add, "even if it
has counter rotating props."























































































and

The symmetric thrust in normal operation is the main
difference, Vmca is still present anytime the engines are
not on the centerline. Having the engines effect the thrust
line the same makes the speed at which you stall, spin and
die the same, it doe snot eliminate the danger.



"RomeoMike" wrote in message
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| Mark Levin wrote:
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| Out of curiosity does this have a marked effect on it's
operation compared
| with the other twins you've flown?
| Any procedures different because of it?
|
| My solo multi time is limited to light twins. The most
noticeable
| difference in "normal" flight is the decrease or absence
of left turning
| tendency in high AOA situations such as TO and climb
because P factor
| and torque from one engine cancels those factors from the
other engine.
| The other main difference with counter rotating props, of
course, is the
| lack of a critical engine. In other words, no more
asymmetrical thrust
| is produced if one engine fails compared to the
other.Therefore, turning
| tendencies are less when practicing critical engine out
procedures (or
| Vmc demos) than they would be in the conventional set up.
I wouldn't say
| that any procedures are different. One still practices the
same things.
| There is still a lot of asymmetric thrust in engine out
scenarios. A
| multi instructor once told me that a twin is like any
other airplane,
| but when it loses an engine it becomes a sled. I would
add, "even if it
| has counter rotating props."
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| and

Jim Macklin wrote:
The symmetric thrust in normal operation is the main
difference, Vmca is still present anytime the engines are
not on the centerline. Having the engines effect the thrust
line the same makes the speed at which you stall, spin and
die the same, it doe snot eliminate the danger.


Guess you're not disagreeing with me, so maybe you meant to respond to Mark.

Probably, sometimes keeping the thread and the thought
processes all in order, a strain.

Did I really get the typo below that says, deer mucous [sort
of]?



"RomeoMike" wrote in message
...
|
|
| Jim Macklin wrote:
| The symmetric thrust in normal operation is the main
| difference, Vmca is still present anytime the engines
are
| not on the centerline. Having the engines effect the
thrust
| line the same makes the speed at which you stall, spin
and
| die the same, it doe snot eliminate the danger.
|
|
| Guess you're not disagreeing with me, so maybe you meant
to respond to Mark.

Mark Levin wrote:

On 30-Nov-2006, RomeoMike wrote:

One twin that I have experience with, the Seminole, does have counter
rotating props.

Out of curiosity does this have a marked effect on it's operation compared
with the other twins you've flown?
Any procedures different because of it?

the Duchess also have counter rotating props. The difference is that
it doesn't have 'critical engine' and should behave similarly whether
you loose the left or right engine.

--Sylvain