Prop sync and noise in twins

Mxsmanic wrote in
:

Dudley Henriques writes:

We had a Cessna 337 on our line for charter use at one time. It had a
sync gauge. Strangely enough, whenever I had occasion to fly this
bird I always ended up syncing the props by ear. You could easily
feel if one of them was out even by a small amount of RPM.

Logically the smallest differences would also be the most annoying,
since they would result in such slow variations. And in theory you
should be able to eliminate them by adjusting RPM manually. But since
the Baron has a prop sync switch it occurred to me that perhaps the
RPM levers aren't precise enough to make it easy to sync the props
(?).

I'm still not clear on whether or not this switch actually moves the
prop levers or what.

I know, send me $200 and I'll tell you fjukktard


Bertie

Bertie the Bunyip wrote:

I know, send me $200 and I'll tell you fjukktard


Bertie

Just be sure to spend it on some counselling, ok?

Same here Dudley..

I have a "few " hours in a 310... I just set them manually, they
stayed in sync very well

I have 2500 hrs on the boat, no auto sync, although they make them.

You engage it once the vessel is moving fwd in gear, then use one
throttle (usually the Starboard) and the Port engine tracks the
master..

The 1st sign of engine trouble is the engines going out of sync
without any aparent reason...

Cheers!

Dave





On Mon, 21 May 2007 22:46:39 -0400, "Dudley Henriques"
wrote:


"Dave" wrote in message
.. .
Yes... it can be REALLY irritating..

I have a twin engine boat, same issue... VERY annoying.. to me, and
many others..

Some don't seem to mind.. (?)

Not only the noise, but the vibrations , when out of sync, can be very
annoying as well...

Dave

We had a Cessna 337 on our line for charter use at one time. It had a sync
gauge. Strangely enough, whenever I had occasion to fly this bird I always
ended up syncing the props by ear. You could easily feel if one of them was
out even by a small amount of RPM.
Dudley Henriques

"Mxsmanic" wrote

I note that the Baron (and presumably other twins) has a prop sync switch
that
somehow synchronizes the prop speeds on both engines. From recordings
I've
heard of the interior noise of the aircraft, it does sound as though props
that are just slightly out of sync can produce a very irritating
intermittent
noise as they move in and out of phase.

Slightly out isn't as bad as way out IMO. One of our guys likes to fly with
that wow-wow-wow-wow going on for hours and it drives me nuts when I'm the
passenger. It's all I can do to prevent myself from reaching over and
adjusting the props myself.

Also, how does the prop sync work? Does it actually move pitch or
throttle
levers or something?

In our aircraft there are pulse generators that monitor engine rpm and feed
a computer. The computer directly controls the right engine prop governor.
The system only works if the engines are already within 50 rpm of each
other. Even then, the system can take up to a minute to sync the props -
it's much easier and quicker to do it manually. Ours has never worked all
that well and we really don't use it, or need it for that matter.

BDS

On 2007-05-22 05:53:03 -0700, "BDS" said:



Slightly out isn't as bad as way out IMO. One of our guys likes to fly with
that wow-wow-wow-wow going on for hours and it drives me nuts when I'm the
passenger. It's all I can do to prevent myself from reaching over and
adjusting the props myself.

Bob Stevens ("There I Was") tells the story of one Bedcheck Charlie
during WW II "who could never sync his props." The irritating noise was
considered even more obnoxious than the bombs he dropped, particularly
since he also never hit anything.




--
Waddling Eagle
World Famous Flight Instructor

Mxsmanic wrote in
:

I note that the Baron (and presumably other twins) has a prop sync
switch that somehow synchronizes the prop speeds on both engines.
From recordings I've heard of the interior noise of the aircraft, it
does sound as though props that are just slightly out of sync can
produce a very irritating intermittent noise as they move in and out
of phase.

If you want to simulate that accurately, just talk while your's jerking off
with your sim

Berti e

On May 22, 9:31 am, Bertie the Bunyip wrote:
Mxsmanic wrote :

I note that the Baron (and presumably other twins) has a prop sync
switch that somehow synchronizes the prop speeds on both engines.
From recordings I've heard of the interior noise of the aircraft, it
does sound as though props that are just slightly out of sync can
produce a very irritating intermittent noise as they move in and out
of phase.

If you want to simulate that accurately, just talk while your's jerking off
with your sim

Berti e

Perhaps you could drill a hole in your "English As A Third Language"
textbook and hump the snot out of it.

Leave it open so you might learn something in that 5 second interval
betwixt engage-disengage-ment as you peer out the airport hotel window
for a little (OH!) plane spotting.

EatMe wrote in
ups.com:

On May 22, 9:31 am, Bertie the Bunyip wrote:
Mxsmanic wrote
:

I note that the Baron (and presumably other twins) has a prop sync
switch that somehow synchronizes the prop speeds on both engines.
From recordings I've heard of the interior noise of the aircraft,
it does sound as though props that are just slightly out of sync
can produce a very irritating intermittent noise as they move in
and out of phase.

If you want to simulate that accurately, just talk while your's
jerking off with your sim

Berti e

Perhaps you could drill a hole in your "English As A Third Language"
textbook and hump the snot out of it.

Leave it open so you might learn something in that 5 second interval
betwixt engage-disengage-ment as you peer out the airport hotel window
for a little (OH!) plane spotting.


Oh dear. someone is trying to **** me off.


Well, could be fun..

Bertie