Engine configuration

Greetings!

My last post provoked a long and interesting series of threads so I am
emboldened to make another post.

This question concerns the configuration or layout of an engine. I have
noticed that air-cooled engines tend to have an opposed configuration
whereas liquid-cooled engines tend to have a V configuration. Both are
also available inline but I'll take a leap and say these are a minority
(I'm talking about current production engines not historical engines).
There are some liquid-cooled horizontally-opposed engines but I can't
think of any air-cooled "V" engines. Why is this? It suggests to me that
the advantages of the V configuration are specific to liquid cooling. Is
this really the case?

The Wikipedia article on "V Engine" is quite short but it includes this:

"Certain types of V engine have been built as inverted engines,
most commonly for aircraft. Advantages include better visibility
in a single-engined airplane, and lower centre of gravity."

OK, these are two pretty good advantages! There are no disadvantages
listed. So why isn't the Lycoming O-540 or the Continental O-520 an
inverted V?

Regards,

Michael

Michael Henry a écrit :

why isn't the Lycoming O-540 or the Continental O-520 an
inverted V?


They are derived from opposed engines, and the manufacturers thought
easier to retain the same cylinders and cylinder heads as their 4
cylinder counterparts.

There have been a number of aircooled inverted engines in the post WWII
period.

But it is hard to make statistics with Lyco/Cont being the sole small
engine manufacturers for decades.

Best regards,
--
Gilles
http://contrails.free.fr

GTH wrote:
Michael Henry a écrit :

why isn't the Lycoming O-540 or the Continental O-520 an
inverted V?


They are derived from opposed engines, and the manufacturers thought
easier to retain the same cylinders and cylinder heads as their 4
cylinder counterparts.

OK so I just push my question back one generation: why is the O-360 not
an inverted V?

I'm asking more from a theoretical point of view. What is it that makes
the opposed configuration more attractive than the V configuration for
air-cooled engines? Likewise: what is it that makes the V configuration
more attractive than the opposed configuration for liquid-cooled engines?

There are new aircraft engine designs out the the Jabiru as an
air-cooled example and the Orenda as a liquid-cooled example. They
follow the same pattern that has become the norm.

There have been a number of aircooled inverted engines in the post WWII
period.

....and in the pre-WWII period! The deHavilland Gipsy Major being a
notable example.

Michael Henry wrote:

what is it that makes the V configuration
more attractive than the opposed configuration for liquid-cooled engines?

Rotax 4 strokes are opposed, they also make inline 2 stroke air/water
cooled engines too...

In article ,
Michael Henry wrote:

GTH wrote:
Michael Henry a écrit :

why isn't the Lycoming O-540 or the Continental O-520 an
inverted V?


They are derived from opposed engines, and the manufacturers thought
easier to retain the same cylinders and cylinder heads as their 4
cylinder counterparts.

OK so I just push my question back one generation: why is the O-360 not
an inverted V?

I'm asking more from a theoretical point of view. What is it that makes
the opposed configuration more attractive than the V configuration for
air-cooled engines? Likewise: what is it that makes the V configuration
more attractive than the opposed configuration for liquid-cooled engines?

There are new aircraft engine designs out the the Jabiru as an
air-cooled example and the Orenda as a liquid-cooled example. They
follow the same pattern that has become the norm.

There have been a number of aircooled inverted engines in the post WWII
period.

...and in the pre-WWII period! The deHavilland Gipsy Major being a
notable example.

I think one of the factors you're overlooking is vibration.

Certain engine configurations have less vibration due to the arrangement
of the reciprocating and revolving components:

A 90 degree V-8; a straight-6; ...

....and a flat-4.

A V-4 would have more vibration than a flat-4.

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling four feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect if you
sit in the bottom of that cupboard."

Alan Baker a écrit :

I think one of the factors you're overlooking is vibration.

Certain engine configurations have less vibration due to the arrangement
of the reciprocating and revolving components:

A 90 degree V-8; a straight-6; ...

...and a flat-4.

A V-4 would have more vibration than a flat-4.


Right on that one.
Also it is interesting to observe that only *short* crankshaft engines
achieved success in civilian airplanes after WWII : radials, short flat
fours, or sixes.

Inline engines with their longer crankshaft have only survived in
marginal quantities in Eastern Europe.

Best regards,
--
Gilles
http://contrails.free.fr

Opposed engines are simple and strong. Inverted engines are much
more complicated.

First: The cylinder extends into the crankcase so that oil thrown off
the bearings doesn't drain off the case walls and run into the
cylinders. Could cause hydraulic lock, certainly would use a lot more
oil.

Second: That oil can't be stored in the crankcase. There has to be a
separate oil tank, usually on the firewall.

Third: The oil has to be pumped out of the engine into the tank. My
Auster had a Gipsy Major inverted inline, and it had THREE oil pumps:
one to pump oil from the tank into the engine's workings for
lubrication, and two more to scavenge the case; one pumped oil out of
the front, the other out of the back. Because the engine gets tipped
up and down so much in an airplane, two outlets are necessary lest oil
pile up and start running into the jugs at the low end. One pump can't
do them both, or it would be happy to suck air from the high end
instead of pulling the oil out of the low end.

Fourth: The rockers and valve stems need either pressure lubrication
and ANOTHER scavenge pump, or, as with the Gipsy, the covers are taken
off occasionally and filled with oil. A pain, that is.

In spite of all that, I like the looks of the inverted
installation, confirming that, like so much of homebuilding and the
rest of general aviation, emotions usually trump common sense. (Just
look at the beautiful but huge, ridiculously expensive projects some
of us average-income guys start on, and are never able to finish.
Emotions over common sense.)


Dan

On Thu, 13 Dec 2007 20:02:54 +0100, GTH
wrote:

Alan Baker a écrit :

I think one of the factors you're overlooking is vibration.

Certain engine configurations have less vibration due to the arrangement
of the reciprocating and revolving components:

A 90 degree V-8; a straight-6; ...

...and a flat-4.

A V-4 would have more vibration than a flat-4.


Right on that one.
Also it is interesting to observe that only *short* crankshaft engines
achieved success in civilian airplanes after WWII : radials, short flat
fours, or sixes.

Inline engines with their longer crankshaft have only survived in
marginal quantities in Eastern Europe.

Best regards,
***************************************
My first military aircraft was the PT-19A with a 200 HP inverted
Franklin air cooled engine.

Primary reason they are not flying today is the PT-19 had a bunch of
expensive AD's on the wood in the wing.

Don't ever remember the engine over temping and bird did not have any
cowel flaps.

Don't remember any engine failures on field during my Primary Training
period. Chit chat was that it was a good engine.

Big John

On Thu, 13 Dec 2007 18:19:14 GMT, Alan Baker
wrote:

In article ,
Michael Henry wrote:

GTH wrote:
Michael Henry a écrit :

why isn't the Lycoming O-540 or the Continental O-520 an
inverted V?


They are derived from opposed engines, and the manufacturers thought
easier to retain the same cylinders and cylinder heads as their 4
cylinder counterparts.

OK so I just push my question back one generation: why is the O-360 not
an inverted V?

I'm asking more from a theoretical point of view. What is it that makes
the opposed configuration more attractive than the V configuration for
air-cooled engines? Likewise: what is it that makes the V configuration
more attractive than the opposed configuration for liquid-cooled engines?

There are new aircraft engine designs out the the Jabiru as an
air-cooled example and the Orenda as a liquid-cooled example. They
follow the same pattern that has become the norm.

There have been a number of aircooled inverted engines in the post WWII
period.

...and in the pre-WWII period! The deHavilland Gipsy Major being a
notable example.

I think one of the factors you're overlooking is vibration.

Certain engine configurations have less vibration due to the arrangement
of the reciprocating and revolving components:

A 90 degree V-8; a straight-6; ...

...and a flat-4.

A V-4 would have more vibration than a flat-4.

Yea, ever drive a Corsair V4? Even with a balance shaft they are not
smmoth.


--
Posted via a free Usenet account from http://www.teranews.com

In article ,
clare at snyder.on.ca wrote:

On Thu, 13 Dec 2007 18:19:14 GMT, Alan Baker
wrote:

In article ,
Michael Henry wrote:

GTH wrote:
Michael Henry a écrit :

why isn't the Lycoming O-540 or the Continental O-520 an
inverted V?


They are derived from opposed engines, and the manufacturers thought
easier to retain the same cylinders and cylinder heads as their 4
cylinder counterparts.

OK so I just push my question back one generation: why is the O-360 not
an inverted V?

I'm asking more from a theoretical point of view. What is it that makes
the opposed configuration more attractive than the V configuration for
air-cooled engines? Likewise: what is it that makes the V configuration
more attractive than the opposed configuration for liquid-cooled engines?

There are new aircraft engine designs out the the Jabiru as an
air-cooled example and the Orenda as a liquid-cooled example. They
follow the same pattern that has become the norm.

There have been a number of aircooled inverted engines in the post WWII
period.

...and in the pre-WWII period! The deHavilland Gipsy Major being a
notable example.

I think one of the factors you're overlooking is vibration.

Certain engine configurations have less vibration due to the arrangement
of the reciprocating and revolving components:

A 90 degree V-8; a straight-6; ...

...and a flat-4.

A V-4 would have more vibration than a flat-4.

Yea, ever drive a Corsair V4? Even with a balance shaft they are not
smmoth.

Um, somebody check me, but didn't the Corvair come with only one engine:
a flat 6?

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling four feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect if you
sit in the bottom of that cupboard."