Marine Engine / Life at Full Power
pa...@kahuna.nrl.navy.mil
This responce from Mercruiser service on the rec.boats group should be of
interest to the battle over auto/marine engine conversions being usable
at high power settings.
In article <4tiebd$m...@newsbf02.news.aol.com>, mcse...@aol.com (MCSERVICE) wrote:
...snip...
>
>Don't believe one of the other responses to your massage about only being
>able to run at WOT for a few minutes ot the engine will self destruct.
>That's just NOT TRUE. Part of our testing to qualify an engine requires it
>to run at WOT under normal prop load for hundreds of hours with no
>failure. The relative few hours of WOT operation that a recreational
>boater operates at is no problem for a sterndrive engine.
>
>Larry Engelbert
>Director - MerCruiser Service
>mcse...@aol.com
Robert Van Zant
>I would submit that it's time to move on to topics of conversation
>beyond this Lamar/myth/scare tactic because there is no evidence to
>support his contention.
My nomination for 'Understatement of the Year' award.
bob
Charles K. Scott
In article <4tnk9u$e...@ra.nrl.navy.mil>
pa...@kahuna.nrl.navy.mil () writes:
Many thanks pa...@kahuna.nrl.navy.mil, to me this is icing on the cake.
I'd like to summerize, if I may, the events leading up to this firball
we've had for the last year over whether auto engines can or cannot be
used in aircraft. The most vehement naysayer has been Paul Lamar. He
made several statements based on his mechanical engineering education
(hey that's what he's stated several times) to the affect that auto
engines just cannot work a an aircraft powerplant.
From memory, there was the statement that they would explode like a
hand grenade. He also stated that the main bearing webs would "crumble
to dust". And we now have the current "the cranks can't take it"
thought. There was this whole nuther issue of horsepower ratings which
I will not get into during this post.
Paul also claimed to have been a member of the original Chapparal
effort which changed the way racing built cars and paved the way to the
current use of aerodynamics in auto racing although at that time he was
called an aerodynamicist, not a mechanical engineer. With that kind of
background you'd think he'd remember that the engines the Chapparal
used were Chevy's and they were often required to put out very high
horsepower for periods sometimes as long as 24 hours at a time
(Sebring, for example).
Many of us have repeatedly asked Paul to give us some (any) examples of
auto engines being used in airplanes and blowing up or breaking the
crank, to no avail. He had no reasonable examples. He cited one of
the first Cirrus homebuilts to fly which had a V-8, but checking on the
incident revealed that it overheated and burned. He also cited the
Pond Racer. It's likely the Pond Racer did blow an engine but it was
racing in the Unlimited Catagory at Reno at the time and racing
conditions, as we all know, are not directly comparable to GA type
operations.
On the other hand we have what appears to me to be overwhelming
evidence that the V-6, and V-8's appear to suffer no ill effects, other
than the expected higher wear rate, when used to power airplanes. The
most obvious evidence would be the examples of people who did install
and are now using them in their airplanes, some of them for over 1,000
hours in flight with no reports of cranks breaking, web's
disintegrating, any major mechanical difficulties or even any abnormal
wear. We also have reports from companies and individuals developing
V-8's for the homebuilt and experimental aviation market who put many
hundreds of hours of dyno time on the engines with either normal wear
recorded or no wear. We have the FAA certifying one engine
(Lexus/Hamilton which is running at relatively high rpm and putting out
over 300 hp if I remember correctly) and working with at least one
other company to certify another (marine HO350). We have the evidence
that Chevy V-8's have been used for years powering prop driven airboats
down in Florida and other swampy areas without any reports of engine
destruction of any kind.
I would submit that it's time to move on to topics of conversation
beyond this Lamar/myth/scare tactic because there is no evidence to
support his contention.
Corky Scott
BAF523
<slrn5051g4....@van.inc.net>
>>I would submit that it's time to move on to topics of conversation
>>beyond this Lamar/myth/scare tactic because there is no evidence to
>>support his contention.
> My nomination for 'Understatement of the Year' award.
>bob
=======
I second that!
Bruce A. Frank