"David Billington" wrote in message
...
On 04/12/2019 14:26, Jim Wilkins wrote:
"Gunner Asch" wrote in message
...
On Mon, 25 Nov 2019 09:04:53 -0800, pyotr filipivich
wrote:

Steam transportation required stronger boilers,
As I understand it. one of the critical features of steam engines
(smooth round cylinders which allowed a tight fit) came as a
result
of
development in the armaments trade: the ability to bore out
cannon
barrels.
And so forth.

airplanes needed lightweight engines.
Although I have plans for a steam powered aeroplane. (circa 1908
iirc)
Go to YouTube for videos of the flight of the Bessler Steam Plane.

Flew quite nicely.

Gunner
Advances in material science enabled flash boilers to be light
enough
to fly, but the lower thermodynamic efficiency of water-based steam
engines made them impractical due to higher fuel weight. Their only
real advantage is that they can burn cheaper solid fuel such as
wood
or coal.
https://en.wikipedia.org/wiki/Engine_efficiency
" In effect, diesels ran six times as far as steamers utilizing
fuel
that cost only twice as much. This was due to the much better
thermal
efficiency of diesel engines compared to steam."

Mass-produced gasoline aircraft engines reached 34% efficiency by
recovering exhaust energy with turbines. Steam engines can only
achieve that with bulky and fragile condensers that were never
practical on locomotives, let alone aircraft. Also unlike ships and
power plants there's no reliable water source to cool the condenser
up
there, and air condensers weren't the answer because the engine
needs
to be able to dissipate the most heat at takeoff in hot ground air.
Without a condenser steam engine efficiency runs to 10% or less.

Condensing steam locomotives were produced successfully and used in
dry parts of the world where water was hard to come by

https://en.wikipedia.org/wiki/Conden...eam_locomotive


"The system was satisfactory for tram engines (which were very
low-powered) but would not have worked for larger railway
locomotives."

http://cs.trains.com/trn/f/740/t/209...rt=ASC&pi332=2
"South African Railways was famous for its condensing 4-8-4's, which
were built to support steam operation through a desert where water was
unavailable. The condensing gear, which was mounted in the tender,
had its own maintenance needs above and beyond that of the rest of the
locomotive. SAR also had otherwise identical conventional 4-8-4's for
service elsewhere, which implies that the condensing gear existed only
for a special situation."

Their disadvantages were tolerated when necessary to solve more
serious problems. Somewhere I read that their maintenance was quite
high, due partly to cracking from hammer blow. Your small loading
gauge severely restricted what could be hung on the outside in the air
flow.