From: Rotary Engine <rotaryeng@earthlink.net>
Subject: R-3350-93 not nice
To: "AAA Put this in the To box" <rotaryeng@earthlink.net>
Date: Sunday, December 28, 2008, 9:37 PM
Just to keep the TCP discussion alive, I recently got this
about some sort
of variant on the R3350. What versions had PRT vs TC vs
none at all? Who
made them, both CW and P/W, and ? Marc Wiese

Subject: R-3350-93


Marc, I flew the 3350-93 for 2000 hours on Lockheed 1049
and 1649 Connies in
the AF. That engine was a mechanical monster. At the time
the air lines
majored the engine at 1000 hours but budget limited us to
life of the engine
until failure. We never had an engine live past 1000 hours.
I had 33 engine
losses in 36 months, all of them far,far out over the North
Atlantic and
over the ice cap. Less than 3 good strong engines was a
ditch condition! I
was once down to 2.5 engines that did not end pretty on
Cape Cod. Our wing
had several aircraft with engine fires over the water and
the Connie had a
magnesium main spar that burned readily! We lost four
aircraft into the N.
Atlantic with high losses. Not a happy time!

Chuck

Chuck who? Was he a flight engineer?

You hear different stories from different people. Some say
they never had
problems. Curtiss Wright claimed the TBO was 3000 hours. I
think a lot
depended on the skill of the flight engineer. Some say they
lost an engine but they still  made it to their destination.
Curtiss Wright claimed 9000 engine were built with over 7.5
million accumulated flight hours. Don't forget that
technology was 60  years ago. I think Hurant below was a
flight engineer.


Paul Lamar

-------- Original Message --------
Subject:     R3350
Date:     Sun, 7 Dec 2008 10:26:32 -0600
From:     h karibian
To:     <rotaryeng@earthlink.net>



The 3350 was leaned to 10% BMEP under a certain threshold
of power (I don't
remember what it was) because of the power enrichment valve
in the
carburetor. Above that power setting, but below METO
(maximum continuous
power setting below takeoff power) and climb power, you
used "Auto Lean".
The two injection pumps, initially, were connected with a
synchronizer bar
that would change with temperature and vibrations but were
later replaced
with flow dividers that equalized the fuel to each
cylinder. The engines
were BMEP or manifold pressure limited on takeoff,
whichever limit was
reached first, and you shifted to high blower when you ran
out of throttle
at low blower in climb. Karibian

Bob Buck (wrote Weather Flying and an interesting
autobiography) was a
captain and chief pilot for TWA and flew Connies (among
lots of other
types).  My recollection of his comments were that the
engine
reliability was crummy when running in the high ratio
blower setting,
but was excellent when running in low blower.  I don't
believe the
problem was in the TC, but more likely in thermal
management.  He said
that TWA's operation just lived with the reduced
performance (slower
cruise speed) at high altitude - running low blower.  He
flew some of
the longest Connie missions - from the west coast of the US
to London.


Regards,

Matt-

Curtss Wright had a lot of problems with the exhaust
valves. Most of the TC
development money was spent making them live. If an exhaust
valve broke
up parts of it would go out through the exhaust pipe and
take out a turbine.
The flight engineer was instructed to shut down the engine
to prevent
further damage. The Air Force Connies had large radomes
that increased
the drag so performance on 3 engines was more marginal.

Need I mention the rotary has no exhaust valves :)

Here is a another good book on the subject.

"Lockheed Constellation" by Stringfellow &
Bowers Motorbooks ISBN 0-87938-379-8.
Therein the descriptions of the TWA nineteen hour non-stop
flights from San
Francisco to London and twenty three hours, nineteen minute
flights London to
San Francisco are described.

-----------------------------------------------------------------------
A couple of things. As I recall the Air Force engines used
carbs which were much
harder to insure equal mixture in each cylinder. Proper
mixture was critical to the life of the exhaust valves and
turbine as it is today. Commercial RS3350TC engines used
fuel injection with an auto lean option. Here are a few jpgs
on the subject. Modern aircraft engine's exhaust valves
would last longer with EFI auto leaning. Mistral has auto
leaning on their rotary engines.


Paul Lamar

Paul,
Chuck is a pilot friend of mine who owns/flys a plane like
mine. I don't
know what his flight crew status was (I'll ask) but it
appears from his
messages that he was in the AF flying Connies with an
engine variant that
you shifted from low to high blower at about 7500 feet.
Marc

The AD-1 through AD-4 Douglas Skyraiders had straight carburetor
engines (no PRT's) with manifold pressure regulators, which we
regularly set to overboost for the pleading pilots because the
one carrier cruise I was on, the skipper ran the flight deck,
instead of the Air Boss, and he insisted all deck launches be
made from the calibrated deck point rather than give the
following planes more deck run. The bomb laden planes would
disappear off the bow and not reappear until they were quite
a ways ahead, still staggering for altitude.
When I joined a civilian cargo airline I was surprise at how
little the ex-airline flight engineers I met knew about
operating the R-3350 turbo compound engines.

Hurant Karibian