Engine configuration

"Darrel Toepfer" wrote in message
. 18...
"Bill Daniels" bildan@comcast-dot-net wrote:

I can think of two inverted "V" air cooled aero engines that were
produced in quantity.
One is the German Argus As 10C 240HP used in the Me 108 and the Storch
and the other is the American Ranger V-770 inverted V12.
See: http://www.oldengine.org/members/die...ord/Ranger.htm
and http://en.wikipedia.org/wiki/Argus_As_10

LOM's are still in production: http://www.moraviation.com

I thought the original question was about inverted "V" engines. While the
LOM and Mikron engines are excellent products, they are inverted I-6 and I-4
engines, not a "V".

BTW, neither the LOM or the Ranger engines suffer from 'hydraulic lock'
which seems to be mostly related to P&W radials. I owned a Ranger inverted
in-line 6 which powered a PT - 19 and it never even smoked on start. I also
flew a Zlin with a LOM I-6 and it didn't give problems.

I think the inverted engines allow a nicer looking cowl and they do improve
the pilots visibility forward and down.

Bill Daniels

"Bill Daniels" bildan@comcast-dot-net wrote:

I thought the original question was about inverted "V" engines. While
the LOM and Mikron engines are excellent products, they are inverted
I-6 and I-4 engines, not a "V".

Bootstrap a couple of them together! ;-)

Didn't we discuss an old US tank engine in here? It was 5 or more
engines geared together. Lots of unique engines in tanks, air cooled gas
radials, 90 degree "V" diesels, etc...

BTW, neither the LOM or the Ranger engines suffer from 'hydraulic
lock' which seems to be mostly related to P&W radials. I owned a
Ranger inverted in-line 6 which powered a PT - 19 and it never even
smoked on start. I also flew a Zlin with a LOM I-6 and it didn't give
problems.

I think the inverted engines allow a nicer looking cowl and they do
improve the pilots visibility forward and down.

Yep...

From what I've seen historically, the engine configuration had to do
with 5 factors:


1. how to machine it, feed it, and get it lit (this was the major
issue before WW 1)
2. how to keep it cool (hence the popularity of the radial, which was
originally designed to power the Langley aerodrome)
3. because everybody else did it that way
4. cost
5. how to cram it into the airframe

Number 3 now seems to be the most popular reason to use an air-cooled
flat.

Harry

"Bill Daniels" bildan@comcast-dot-net wrote in message
...

"Darrel Toepfer" wrote in message
. 18...
"Bill Daniels" bildan@comcast-dot-net wrote:

I can think of two inverted "V" air cooled aero engines that were
produced in quantity.
One is the German Argus As 10C 240HP used in the Me 108 and the Storch
and the other is the American Ranger V-770 inverted V12.
See: http://www.oldengine.org/members/die...ord/Ranger.htm
and http://en.wikipedia.org/wiki/Argus_As_10

LOM's are still in production: http://www.moraviation.com

I thought the original question was about inverted "V" engines. While the
LOM and Mikron engines are excellent products, they are inverted I-6 and
I-4 engines, not a "V".

BTW, neither the LOM or the Ranger engines suffer from 'hydraulic lock'
which seems to be mostly related to P&W radials. I owned a Ranger
inverted in-line 6 which powered a PT - 19 and it never even smoked on
start. I also flew a Zlin with a LOM I-6 and it didn't give problems.

I think the inverted engines allow a nicer looking cowl and they do
improve the pilots visibility forward and down.

Bill Daniels

This is not my area of occupational or other specialty, but...

I think that you will find that the hydraulic lock, and also the lower plug
fouling problem in the bottom cylinders, is a common problem shared by all
of the radials that I have seen and is not exclusive to Pratt and Whitney.

Basically, the issue is that the oil storage tank is located at the top of
the engine compartment, well above the crankshaft, which has both a major
advantage and a major dissadvantage. The advantage is that the oil will
gravity feed into the intake of the pressure pump--making it very easy to
maintain full oil flow and pressure at any altitude without any requirement
for any additional pump to lift the from the tank to the pressure pump. (I
have no idea whether any reciprocating engines even actually had such a need
at any altitude that they were flown, but it is theoretically possible with
some combination of maneuvering loads and very high altitude.) There is an
additional benefit in that there is no delay between starting the engine and
pumping pressurized oil to the bearings. However, the well known
dissadvantage is that the oil from the storage tank will slowly drain
downward through the clearances of the oil pressure pump and through the
main and big end bearings, and into the lowest cylinders. Over time,
ranging from hours to days, it will fill the "bottoms" of one or more
pistons and drain slowly between the pistons and cylinder walls, between the
ring gaps, and into the combustion chambers of one or more cylinders. The
resulting pools of oil in the combustion chambers then cause the familiar
spark plug fouling and, in extreme cases, hydraulic lock.


As to the matter of inverted Vee engines: Personally, I like them; but I
really don't see any advantage over a "flat" engine, and only a slight
advantage over an upright Vee with offset reduction drive.
In short: Why fix what aint broke?

I hope this helps.
Peter

On Dec 13, 4:53 am, Michael Henry wrote:
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

VF-4 Wisconson industrial engine is an air cooled V configuration.

On Thu, 13 Dec 2007 21:53:23 +1000, Michael Henry
wrote:

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?

The practical difference in visibility between an inverted-V and a horizontally
opposed engine is minor, especially when the airplane they're used on has
tricycle gear vs. a taildragger. An inverted-V engine has a significant
visibility advantage over a radial, but they're no longer common in light
aircraft.

Same holds true for the lower CG: The inverted-V is much better than a radial,
but not that much better than the horizontally opposed engine. If you're
speaking of an air-cooled engine, much of the mass is in the crankcase, anyway,
irrespective of which way the cylinders poke.

And as you say: There are no disadvantages *listed* in a short Wikipedia
article. That does not mean there are no disadvantages. Access to the carb and
other elements that mount below the crankcase is probably more awkward; the
spark plugs may be more susceptible to oil fouling. For that matter, the
inverted-V may have the same problems with hydro lock as a radial...probably in
itself enough of a reason to favor horizontally opposed.

Ron Wanttaja

Ron Wanttaja wrote:
On Thu, 13 Dec 2007 21:53:23 +1000, Michael Henry
wrote:

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?

The practical difference in visibility between an inverted-V and a horizontally
opposed engine is minor, especially when the airplane they're used on has
tricycle gear vs. a taildragger. An inverted-V engine has a significant
visibility advantage over a radial, but they're no longer common in light
aircraft.

Same holds true for the lower CG: The inverted-V is much better than a radial,
but not that much better than the horizontally opposed engine. If you're
speaking of an air-cooled engine, much of the mass is in the crankcase, anyway,
irrespective of which way the cylinders poke.

And as you say: There are no disadvantages *listed* in a short Wikipedia
article. That does not mean there are no disadvantages. Access to the carb and
other elements that mount below the crankcase is probably more awkward; the
spark plugs may be more susceptible to oil fouling. For that matter, the
inverted-V may have the same problems with hydro lock as a radial...probably in
itself enough of a reason to favor horizontally opposed.

Ron Wanttaja
Is this thread dead yet?

Actually, there is a real structural advantage to the flat engine over
the V. The block can be lighter in the opposed configuration, for the
same strength.

Charlie

On Dec 18, 7:36 pm, Charlie wrote:
Ron Wanttaja wrote:
On Thu, 13 Dec 2007 21:53:23 +1000, Michael Henry
wrote:

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?

The practical difference in visibility between an inverted-V and a horizontally
opposed engine is minor, especially when the airplane they're used on has
tricycle gear vs. a taildragger. An inverted-V engine has a significant
visibility advantage over a radial, but they're no longer common in light
aircraft.

Same holds true for the lower CG: The inverted-V is much better than a radial,
but not that much better than the horizontally opposed engine. If you're
speaking of an air-cooled engine, much of the mass is in the crankcase, anyway,
irrespective of which way the cylinders poke.

And as you say: There are no disadvantages *listed* in a short Wikipedia
article. That does not mean there are no disadvantages. Access to the carb and
other elements that mount below the crankcase is probably more awkward; the
spark plugs may be more susceptible to oil fouling. For that matter, the
inverted-V may have the same problems with hydro lock as a radial...probably in
itself enough of a reason to favor horizontally opposed.

Ron Wanttaja

Is this thread dead yet?

Actually, there is a real structural advantage to the flat engine over
the V. The block can be lighter in the opposed configuration, for the
same strength.

Charlie

Opposed engines have less drag than a radial or vee. Opposed
engines are easier to see over.

Buy they sure look funny in a warbird replica.

Dan

a écrit :

Opposed engines have less drag than a radial

Agreed

or vee

Why would it be so ?
An opposed engine is much larger just behind the prop, when a Vee is
more easily streamlined.
Would you care to elaborate ?

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

On Dec 20, 6:49 am, GTH wrote:
a écrit :

Opposed engines have less drag than a radial

Agreed

or vee

Why would it be so ?
An opposed engine is much larger just behind the prop, when a Vee is
more easily streamlined.
Would you care to elaborate ?

Best regards,
--
Gilleshttp://contrails.free.fr

A vee takes up as much flat-plate area as an opposed, because
it's not likely to be cowled so the slipstream can flow through the
vee between the cylinder banks. The opposed and vee both have
crankcases and cylinder banks that are in the way, and the case of the
vee tends to be larger, forming a three-armed affair rather than the
two of the opposed. Some opposed engines have been very tightly cowled
for racing purposes, with the carb and such behind the engine instead
of under it.
Most vee-engines have some sort of reduction so that higher
hp can be obtained from a smaller configuration. These can be smaller
than opposed engines for the same hp, but they'll be heavier, too. A
direct-drive vee is pretty big. The Argus was one.
The inline engine is much more easily streamlined, but its
crank is longer and so has to be larger in diameter to obtain the
stiffness required, and as it gets larger it gets heavier.

Dan