John Freck wrote:
"Emmanuel Gustin" wrote in message ...

I know people at work who can assemble an engine. Being
able to assemble an engine is very basic to the 'mechanic'.


How many of them cast their engine block? Or machine the
pistons, valves, etc.?

An aircraft engine is not a car engine. Car engines are heavily
built and with fairly robust tolerances; they are designed to
run almost forever. WWII aircraft engines were running very
close to material limits, and keeping them operational would
be more akin to tuning the engine of a Formula 1 racing car
than to car-type maintenance. They were also extremely complex
by modern standards. These days, assembly of WWII engines is
limited to a handful of specialised workshops.

Why did you write the above? Today, a corporation specialized to
manufacturing small propeller aircraft for the leisure and corporate
market does exist. I bet there is more than one company making
propeller aircraft.
I will Google for a few minutes in a new window.


As soon as you find a "small propeller aircraft" with a
12 cylinder, 1600 cubic inch engine developing 1400 HP with
a mechanical supercharger being manufactured for the leisure
and corporate market, let me know. The largest piston engine
I found in Piper's lineup was a 6 cylinder putting out 300
Horsepower. Not quite in the same league.



So what? Engines would not merely need acurately turned and
milled parts, they would have to be made of the right alloy and
receive exactly the correct heat and surface treatment. To take
an example of a seemingly simple but extremely demanding part,
the sleeves of Bristol sleeve-valve engines were finished to an
accuracy of two ten-thousandths of an inch in bore, with deviations
of cylindrical shape not exceeding 1/1000 inch over the whole
14-inch length of the sleeve. The process involving milling,
grinding, lapping, and nitritiding to harden the surface. Bristol
actually had to design and build their own tools to succeed in this.

Why can't all of that be done near an airport/airbase? You too are
putting forward and defending the odd concept that it is conceptually
unattainable for planes to be assembled near airports. Are you really
thinking things thru?


I don't think that YOU are thinking things through. How many engine
factories do you think you're going to have building Merlins? There
were (many) dozens of airfields spread throughout England. The wasted
manpower to operate these proposed small scale factories would be
astronomical. Now add in every other major component that you want
to have produced locally. You end up using about 40 times the
manpower to build less than half the components. Wars are affairs
of logistics, and trying to build your weapons and equipment in
place is a pretty quick way to fritter away your resources.


Are you too putting forward the concept that the USAAF can't gather,
cultivate, and grow the sort of labor you indicate a fighter plane
makers would have?


It would presumably be POSSIBLE (theoretically, anyways), but
as I noted above, the only people I'd suggest this to would
be the enemy. Aside from the low production rate, you'd need
a labor force many times the size of your actual operational
units. Imagine over a thousand highly skilled engineers,
machinists, etc., to support a fighter squadron, and able to
supply fewer replacements than the existing supply system at
maybe 10 several times the cost, which can't build up a stockpile
and have to halt production for several weeks to
upgrade when they move to a more powerful mark of the same engine.



http://www.naplesnews.com/03/09/florida/e5099a.htm
A manufacture of propeller dirve planes employs 720 workers
at a manufacturing plant. This plant use 99 acres.
It is adjectent to a small airport which is much small that a large
USAAF airbase of WWII.
http://www.azworldairports.com/airports/p2740vrb.htm

I don't understand the conceptual problem some have with warplanes
being assemble, or built, or recycled, or reconstruted, or what have
you
near or on a military base. Many workers at the Piper Plant of Vero
Beach
learned their skills in the US military too. I think a Piper is the
closest thing to
a WWII fighter in commercial production today.


OK, so you've got 720 people and about 100 acres to provide the
propellers for your aircraft - If you've got another aircraft on
the base with a different propeller, you're up to nearly 1500 people
and 200 acres. Now all you need is an engine, guns (don't forget the
ammunition, with its associated chemical industry), airframe,
instruments, canopy, tires, seat belt, etc., etc., ad nauseum. A
single fighter unit would have a support industry on the order of
the entire Ninth Air Force in personnel.

By the way, this small propeller shop you note- I take it that
it provides propellors for the aircraft operating out of that
nearby airport? How many factories did they build to supply the
propellors to the airports at the next city over?

Mike