Lycoming intake preheater

Anyone know the reasoning for running the intake tubes through the hot oil
in the sump?

Dale Larsen wrote:
: Anyone know the reasoning for running the intake tubes through the hot oil
: in the sump?

1. Make oil not so hot
2. Make package more compact
3. Reduce power
4. Decrease detonation margin.

1&2: good
3&4: notsogood

--
************************************************** ***********************
* The prime directive of Linux: *
* - learn what you don't know, *
* - teach what you do. *
* (Just my 20 USm$) *
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wrote:

Dale Larsen wrote:
: Anyone know the reasoning for running the intake tubes through the hot oil
: in the sump?

1. Make oil not so hot
2. Make package more compact
3. Reduce power
4. Decrease detonation margin.

1&2: good
3&4: notsogood

--


And help reduce suceptability to carb icing.

Richard Riley wrote:

On Sun, 06 Jun 2004 17:46:41 GMT, Richard Lamb
wrote:

:And help reduce suceptability to carb icing.

I've always heard that, but how?

Carb ice, AFAIK, results from the air cooling as it accellerates
through the venturi, and from the temprature drop from the gasoline
evaporating. Both of those things happen in the carb, before the
fuel/air mix goes through the hot oil-bath intake tubes.

I'm sure there's some heat conducted from the hot oil pan to the carb
itself, keeping it a little warmer. But does carb ice form downstream
of the carb, within intake tubes, in a Cont?


Probably just via conduction of the intake pipes.
They do get quite warm...

All I said was 'reduce suceptability' - not prevent.

Even Lycomings need carb heat at times, but they don't seem
to be as critical as Continentals.

Richard

Richard Riley wrote:
: On Sun, 06 Jun 2004 17:46:41 GMT, Richard Lamb
: wrote:

: :And help reduce suceptability to carb icing.

: I've always heard that, but how?

: Carb ice, AFAIK, results from the air cooling as it accellerates
: through the venturi, and from the temprature drop from the gasoline
: evaporating. Both of those things happen in the carb, before the
: fuel/air mix goes through the hot oil-bath intake tubes.

: I'm sure there's some heat conducted from the hot oil pan to the carb
: itself, keeping it a little warmer. But does carb ice form downstream
: of the carb, within intake tubes, in a Cont?

That's pretty much the explanation I've heard/accepted. I'm not too familiar
with the Cont. induction system, but I think the carb body isn't heated by bolting it
to the oilpan. I've gotten carb ice in my Lycoming O-360 a couple of times... usually
in classically expected conditions (40-50degrees, foggish, low MP at low altitudes so
lots of expansion)

-Cory

--
************************************************** ***********************
* The prime directive of Linux: *
* - learn what you don't know, *
* - teach what you do. *
* (Just my 20 USm$) *
************************************************** ***********************

Some engine design need to heat the intake side to prevent condense in the
tubes that lead to engines that run rough, this is a normal design on carb
engines, even in cars. it also prevent ice in the tubes but that is not the
main goal, even cars use warm air to heat the intake air in the carburator
and tube, manually changed (winter/summer) or by a thermostat

Jan Carlsson
www.jcpropellerdesign.com

"Dale Larsen" skrev i meddelandet
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Anyone know the reasoning for running the intake tubes through the hot oil
in the sump?