Re: Continental AV-1790-3 & Allison CD-850-1

On Jul 16, 5:03 pm, Byblow <pstur...@xxxxxxxxx> wrote:
Does anyone here know if the Continental AV-1790-3 was made of
aluminum? I would also like to know if it could have been used before
war's end to power Pershing derivatives.

Continental had been trying to interest the USAAC in aircooled
Flat 12s before the war, and was busy making radials during the war.

That V-12 was a way for Continental to make money postwar,
as turbines were cutting into the radial business.

the GAA/GAF/GAN were all aluminum block DOHC V-8 by Ford,
who also had tried to interest the USAAF in a V-12 aero engine.

The Army was interested in a 400HP V-8, as Continental wasn't
able to make enough radials for tanks, and didn't want a V-12
for the M4 for reason I've never found.

Lets take a side trip. At this time, the British were also looking
for a better tank engine, and turned the Merlin into Meteor by
removing the supercharger, and having aluminum crankcase,
but iron cylinderblocks. a V-8 version was also made, called the
Meteorite. this was roughly equal to the GAA

Back to Ford. They whacked off the end, lost the supercharger
and made a V-8 fed by two carbs.

The cylinders were returned for the heavy Pershings, like
the T29, for a 750hp powerplant, similar to the Merlin.

So there was always a higher power engine available,
had the Army allowed the engine deck to be a foot and a
half longer, which was about the same size needed for the
AV-1790,anyway. Or the 650hp Hall Scott V12 Defender engine
could have been used, but that was a bit heavier

The Crossdrive replaced the Torqmatic tranny, diff, and final
drive. It was shorter than the old unit by about 2 foot. This
allowed the whole thing to fit. It also was a fully regenerative,
which gave better turning ability, rather than the bulldozer
like Cletrac twin stick with fixed turning circle, and easier
on the driver, too. Didn't need Popeye sized arms to steer anymore

However, to stay that short, it was only two speed, where
the Torqmatic had three, and had no converter lockup.
So much of the potential for longer range of the new
engine was lost until it was converted to a diesel and supercharged

If it had been ready for use in Pershings, along with the CD-850-1
crossdrive transmission, would that have made the Pershing a match for
the Panther?

It already was. The Panther had a far weaker gearbox and diff
than the T26, and while the T26 would overheat, it wouldn't
burn itself up like the Panther.
The problem with it was, part of the Army(AGF) didn't think
Tanks should have 90mm guns, another part didn't
want heavier Tanks than the M4(Armor Command). So the
Pershing design sat without a goahead until after Normandy,
Gen Devers requests for the T25 and T26 had been blocked by
Gen McNair since Nov.1943, and were not in combat till well
into 1945