New Airplanes in WWI (ISOT)

rom: (John Redman)


(alfred montestruc) wrote

Imagine if you will I take say a 75mm cannon, hone the bore free of
rifling, then cut it into 6" section to make cylinders for a radial
engine. I can make the engine block out of a ductile iron casting,
the pistons, rods, and shaft from forgings of the same alloy as the
gun tube is made from.

I can then machine fins on the outside of the cylinders and bolt them
to the block. See any showstoppers?

The gun tube is not a homogeneous metal casting though. WW1-era guns
were of wire-wound construction, which is as it sounds; i.e. a series
of inner tube segments around which a thick wire was wound under
tension in a tight spiral with a further metal casing on top.
Effectively it was a like a barrel with one long continuous hoop
around it.

You couldn't literally slice one of these into cylinder lengths and
have a usable tube, nor could you machine cooling fins into it, for
obvious reasons.

I saw some film on the History Channel where they showed the wire wrapping
being hammer forged into a single monolithic piece of metal. Granted the film
was from the 1930, but I would guess it was the same in WW2.

Knifesmiths make "Satan's lace" blades using a similar method of hammer
forging rods into a billet.

Dan, U.S. Air Force, retired

(B2431) wrote in message ...
rom: (John Redman)


(alfred montestruc) wrote

Imagine if you will I take say a 75mm cannon, hone the bore free of
rifling, then cut it into 6" section to make cylinders for a radial
engine. I can make the engine block out of a ductile iron casting,
the pistons, rods, and shaft from forgings of the same alloy as the
gun tube is made from.

I can then machine fins on the outside of the cylinders and bolt them
to the block. See any showstoppers?

The gun tube is not a homogeneous metal casting though.

I never said it was any sort of casting. My impression was that
modern era cannon tubes were either forged from billets, or are made
of hot rolled bar stock that was quenched and tempered then machined
to final shape. Casting (especially steel) is something you generally
do only when having lots of flaws in the metal is ok, which is not the
case in a gun tube.

If you must, then you must use a much larger factor of safety and
thicker gun tube.




WW1-era guns
were of wire-wound construction, which is as it sounds; i.e. a series
of inner tube segments around which a thick wire was wound under
tension in a tight spiral with a further metal casing on top.
Effectively it was a like a barrel with one long continuous hoop
around it.

Cite this please, I goggle searched and found not a single refernce to
that.



You couldn't literally slice one of these into cylinder lengths and
have a usable tube, nor could you machine cooling fins into it, for
obvious reasons.


You could if they were hammer forge welded.


I saw some film on the History Channel where they showed the wire wrapping
being hammer forged into a single monolithic piece of metal. Granted the film
was from the 1930, but I would guess it was the same in WW2.

Hammer forging is the oldest form of welding. It is done by black
smiths. Japanese sword smiths use that technique to make the layers
of the samari sword that make it both strong and hard at the same
time.


Knifesmiths make "Satan's lace" blades using a similar method of hammer
forging rods into a billet.


Sounds plausible to me.

Stephen Harding wrote in message ...
alfred montestruc wrote:

"Keith Willshaw" wrote in message ...

"alfred montestruc" wrote in message

Point of fact, I am very sure that alloys needed either existed, or
reasonable substitutes did.

Evidence please

Artillery gun tubes of that era. They were (obviously) subjected to
high stresses for many thousands of repititions. Obviously the
pressures in a gun tube near the breech during fireing of an artillery
gun are much larger than in an IC engine that has a peak compression
ratio of 10:1 at most.

Imagine if you will I take say a 75mm cannon, hone the bore free of
rifling, then cut it into 6" section to make cylinders for a radial
engine. I can make the engine block out of a ductile iron casting,
the pistons, rods, and shaft from forgings of the same alloy as the
gun tube is made from.

I can then machine fins on the outside of the cylinders and bolt them
to the block. See any showstoppers?

Weight? We do want to fly, rather than tow, this thing around.

Duh!

What is the thickness of a cannon barrel wall compared to an
engine cylinder?


Suggest you look up an engineering text on mechanics of materials and
thermodynamics and work out first the pressure on the inside of the
cylender via thermo calcs, then the required thickness via mechanics
of materials, and the strength of the material used.

I'll give you a hint, cast iron (common material used in IC engines in
WWI) will have a useful strength a whole lot lower than most any grade
of steel. Note also that for serious engine applications you need to
keep stresses lower than the endurance limit of the material, else
have fatigue cracks and failures in service.

http://www.anvilfire.com/FAQs/cast_iron.htm


Typical modern gun steels will have tensile stengths of ~150,000 psi,
with yields stress like 130,000 psi and endurance limits in the range
of 50,000psi. While I am sure the steels used at the start of WWI
were not that good, they may well have had endurance limits in the
30,000psi to 40,000 psi range. When you compaire that to the 20,000
odd of the very best cast iron grades one could get, I think you
should see the point.



What happens to the strength of that cylinder when we reduce
its thickness with machined cooling fins?

What would the weight of an engine built in this manner be,
compared to the engines of the day?

They've been making cannons for 600 years. Not certain I'd
want one as a cylinder in my truck, let alone a combat
aircraft.


SMH

On 8 Jun 2004 22:23:24 -0700, (alfred
montestruc) wrote:

Probably a Japanese Zero. The Zero could land and take off on a
relitivly short grass runway as long as the ground is not soft. The
engine should be within their capacity to build, and that is the main
thing, a late 1930's evolved internal combustion aircraft engine with
lots of power.

The airframe had lots of wood and nothing very sophisticated in terms
of metal parts. The 20mm cannons would make it's firepower something
to be feared.

A Zero would be a terror of the sky in 1918, it can outrun and out
climb everything else. A small number with fuel and ammunition can
rout the other side's airforce and do nasty things in ground attack,
and recon especially given their speed and range.

I'd go for a Me163...

Dangerous, yes, but doable...

Cheers,
Richard

"John Redman" wrote in message om...
One would be if the technology behind it were so difficult for the
other participants to knock off that it became and remained dominant
for long enough to provide air supremacy. This assumes that air
supremacy would have been decisively useful, and I'm not sure it would
have been with anything built in 1914-18 (and given that you've used
your trump card to achieve the supremacy in the first place).

Getting the supremacy sounds like a job for a fighter, eg the Fokker
E-I in 1915. Using it decisively sounds like one for a bomber, and if
I think about bombers that have had a decisive effect on surface
campaigns, I struggle to think of any that did not rely on other
factors. Eg the Stuka was arguably a decisive weapon but only if you
had the Bf109 to clear its path, and I doubt if you could have built
one in 1914-8 anyway.

I don't think this is clear.

Lets assume that the Germans get something like a 1920's
fighter and that it will be a year before the allies can copy it.

A sudden decisive air domination means that the allies have
no arial recon ability. Just that alone could change battles.
A fighter from the 1920s can knock out railroad lines
and bridges, which is a large logistics problem.

Basically, a fighter form the 1920s means that the Germans can
mass for an attack without the Allies knowledge and
can reduce the Allies ability to reinforce the attacked spot.

Even if you think the French can overcome these problems, I doubt the
Russians and/or Serbs can. An early fall of Russia gives Germany the
war.

Sure, it's not the nuclear weapons of World War One, but the war
was such a close thing that the teeter-totter can be made to fall
the other way.

Talleyrand
Who is just as willing to argue for the Allies use of airplanes

"Charles Talleyrand" wrote

A sudden decisive air domination means that the allies have
no arial recon ability. Just that alone could change battles.

Debatable - neither side had useful air recon in 1914, but nobody
seriously suggests this affected events. Also, you can do air recon
over a trench system from a balloon, and you don't need fighters to
defend balloons. You just need to protect them with artillery whose
fuses are pre-set to the height at which an attacking scout would
approach.

A few hundred Fokker D-VIIs would secure air supremacy for whichever
side had them, but I question whether this would change land battles.
AFAIK Germany had air superiority for much of the war, and this didn't
materially alter outcomes on the ground.

A fighter from the 1920s can knock out railroad lines
and bridges, which is a large logistics problem.

Which 1920s fighters could lift, and deliver accurately, a payload
large enough to destroy a militarily-useful bridge? Dive-bombing was
invented in the late 1920s largely because bombloads were so small
that you needed either a huge air force, or direct hits, to cause
worthwhile damage. It was the 1940s before small, agile aircraft
became powerful enough to lift a decent payload - Hurricanes armed
with rockets, for instance. Once you had 1,000hp engines, a lot of
things became possible. I can't see a 1,000hp engine much earlier than
when they did arrive - the mid-1930s.

Even if you think the French can overcome these problems, I doubt the
Russians and/or Serbs can. An early fall of Russia gives Germany the
war.

German war planning was the actually other way around though:
seven-eighths of their forces attacked France because the
Schlieffen-Moltke Plan said that that was how you beat Russia. You
beat France first. If you weren't at war with France, well, you
gratuitously took steps to make sure you were, by demanding insulting
guarantees of neutrality.

The Schlieffen-Moltke Plan further specified that you defeated France
by violating Belgian neutrality. Britain specifically asked Germany in
July 1914 whether she would respect Belgian neutrality in a war with
France. Germany refused to do so, because the Schlieffen Plan could
not be modified, so you invaded Belgium even if this resulted in war
with Britain.

Thus, German doctrine in 1914 effectively was that the best chance of
beating Russia was to go to war simultaneously with Russia, France,
and Britain.

Sure, it's not the nuclear weapons of World War One, but the war
was such a close thing that the teeter-totter can be made to fall
the other way.

Unfortunately, including France and Britain in the war ensured defeat;
and the trench stalemate proved impossible for Germany to break even
after Russia was eventually removed from the allied line-up.