question about engines

Ok,this is probably an obvious question to many of you, but I'll ask
anyway. I usually fly in C172s and C182s with the Lycoming oil cooled
engines that many of you are probably familiar with. I still see planes
with the large radial engines (for instance, like what you would see on
a Dehavilland Beaver) flying around. I had thought maybe these were
just old planes that were well taken care of and still flying after all
these years.....BUT... It seem like the radial engines are popular in
bush flying, and I even see a number of seaplanes with Kenmore Air
(local small airline/airtaxi) with them in use.
1) are these engines still be manufacture on any new planes?
2) Are there any significant advantages to them over the "newer"
engines?

After doing some hunting around for info, I've gotten many varied
answers, but nothing concrete. The main answers I've gotten indicate a
power advantage and the benifits of air cooling father than liquid.
Anything else any of you can think of?

Thanks for your thoughts.!

The crankshaft is very short, stiff and strong. The radial
engine does not use a long whippy camshaft, rather it uses a
cam wheel. The fuel induction system often is into an
impeller which mixes the fuel-air mixture.

In the USA, very few of these engines have been built since
the end of WWII, but they built a huge number.

The air cooled radial is easier to produce in large hp
engines, the in-line engine crankcase casting is more
difficult to make as is the crank and cam shafts. Air
cooling has advantages in arctic weather.

Russia and Poland still have open production lines on radial
engines and western supplies still use WWII P&W and Wright
produced radial engines.

The trend in high horsepower aircraft engines is to the P&W
PT6 series on ag and seaplanes and bush planes.
They sound good.


"Cirrus" wrote in message
ps.com...
| Ok,this is probably an obvious question to many of you,
but I'll ask
| anyway. I usually fly in C172s and C182s with the Lycoming
oil cooled
| engines that many of you are probably familiar with. I
still see planes
| with the large radial engines (for instance, like what you
would see on
| a Dehavilland Beaver) flying around. I had thought maybe
these were
| just old planes that were well taken care of and still
flying after all
| these years.....BUT... It seem like the radial engines are
popular in
| bush flying, and I even see a number of seaplanes with
Kenmore Air
| (local small airline/airtaxi) with them in use.
| 1) are these engines still be manufacture on any new
planes?
| 2) Are there any significant advantages to them over the
"newer"
| engines?
|
| After doing some hunting around for info, I've gotten many
varied
| answers, but nothing concrete. The main answers I've
gotten indicate a
| power advantage and the benifits of air cooling father
than liquid.
| Anything else any of you can think of?
|
| Thanks for your thoughts.!
|

I am not sure if anyone in the U.S. is still building "new" radial
engines, but the WACO YMF-5 built and sold by Classic Aircraft
Corporation has a 275 hp Jacobs R-755 B2, 7-cylinder radial engine that
is remanufactured to new engine tolerances. The work is done by Radial
Engines, Ltd. in Guthrie, Oklahoma.

I will leave it to the A&P guys as well as others with more experience
than me (that would be about all of you here *S*) to compare and
contrast the differences between a new engine and a remanufactured
engine. But if you want a radial . . . you can buy one.

As for the YMF-5, I know it's all in the eye of the beholder, but there
is some lucky stiff near me who flies one, and each time I see or hear
the thing, in the air or on the ground, there is true lust in my heart.

Blue skies . . .

John

Jim pretty much hit the nail on the head.
During WWII there were a huge number of radial engines produced, more than
were needed. The surplus engines were readily available until recently.
The current trend of ag and seaplane operators switching to PT6's is
primarily a direct result of the depletion of the inventory of WWII era new
pickled engines. As they became harder and harder to obtain, operators were
forced to choose between overhauls, rebuilds, new radials, and PT6s. Our ag
operator was simply not satisfied with high price and high maintenence of
the new raidals nor the quality of the overhauled and rebuilt engines,
cylinders, and other components and has began the switch to PT6s.
Jim Burns

"Cirrus" wrote

I usually fly in C172s and C182s with the Lycoming oil cooled
engines that many of you are probably familiar with.

It would be unfair to call them oil cooled engines. Yes, the oil is important
to cooling, but the air flowing across the cylinders and heads is also very
important. That is why some planes with flat engines have cowl flaps that move,
and very tight fitting baffels around the cylinders and heads.

I still see planes
with the large radial engines (for instance, like what you would see on
a Dehavilland Beaver) flying around. I had thought maybe these were
just old planes that were well taken care of and still flying after all
these years.....BUT... It seem like the radial engines are popular in
bush flying, and I even see a number of seaplanes with Kenmore Air
(local small airline/airtaxi) with them in use.

2) Are there any significant advantages to them over the "newer"
engines?

The higher HP is a major reason, since you rarely see flat engines with HP
ratings of more than a bit over 300 HP. There are many radial engines that are
much larger than that.

Another very larger reason for bush pilots using the radial engines are
toughness and ease of repair. In WW II, it was not uncommon for a plane to have
a jug or two shot completely off, all of the oil pumped overboard, and still
have it return to land back onboard the carrier, still running.

Also, it is common for a bush pilot to have a radial engine failure out of range
of home base, land, have a jug removed, taken back to a shop, repaired, and put
back on the plane in the field, and flown out, or just have a new jug and piston
flown in and switched out.
--
Jim in NC

Another very larger reason for bush pilots using the radial engines are toughness and ease of repair.

What (in the design) makes this so?

Jose
--
"There are 3 secrets to the perfect landing. Unfortunately, nobody knows
what they are." - (mike).
for Email, make the obvious change in the address.

"Jose" wrote in message
...
Another very larger reason for bush pilots using the radial engines are
toughness and ease of repair.

What (in the design) makes this so?

Ask the US Navy, for many years. The radial engine is the only type that would
be considered aboard aircraft carriers.

I would think that the major thing is the construction of the crankshaft, and
the great toughness that it has to have, to withstand that many pistons, of high
horsepower, on one throw.

If a jug blows off, or seizes, it thrashes the rod until there is nothing left
banging around. If a multi throw crankshaft had to do the same thing, it would
usually bent or break, thus stopping all horsepower from being produced.

A jug on a radial is also more out in the open, than an opposing engine, and
especially more so than an inline engine, thus making a changeout easier.

I'm sure there are other factors that I am missing, but those are the ones that
come to mind quickly, from what I have read.
--
Jim in NC

On 7 Dec 2006 09:30:44 -0800, "John" wrote:

I will leave it to the A&P guys as well as others with more experience
than me (that would be about all of you here *S*) to compare and
contrast the differences between a new engine and a remanufactured
engine. But if you want a radial . . . you can buy one.

Last I had heard Harrison Ford ended up with a brand spanking new
(disregarding "calender" time) R-985 on his Beaver.

Wonder how much it cost him...

Back in the good old days, when they o-hauled a 985 they stamped the
total time on the front crankcase plate. Have seen a couple plates
that had some scary rows of numbers on them.

TC

"John" wrote in message ps.com...
:
: I am not sure if anyone in the U.S. is still building "new" radial
: engines, but the WACO YMF-5 built and sold by Classic Aircraft
: Corporation has a 275 hp Jacobs R-755 B2, 7-cylinder radial engine that
: is remanufactured to new engine tolerances. The work is done by Radial
: Engines, Ltd. in Guthrie, Oklahoma.
:



http://www.wacoclassic.com/intro.html

http://www.radialengines.com/

Jim and everyone, thanks for your great replys- I really appreciate it.
And Morgans, thanks for pointing out the oil cooled+Air cooled cessna
182 engine distinction. I actually knew that in the back of my head,
but should have been paying more attention....


Cheers everyone,
Jamie