Pratt & Whitney X-1800/XH-2600 & XH-3130/3730

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Zipper730

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Which design was proposed first, and what roles were the XH-3130/3730 designed for?
 
Pratt & Whitney had three liquid cooled engine projects in the late 1930s. The first one was the X-3130. This was an X-24 poppet valve engine with a displacement of 3130 cu. in. for the Navy. The second engine was the "Experimental 1800HP". This was an H-24 sleeve-valve design of 2240 cu. in.displacement. Conceptually it was P&W's take on the Napier Sabre. As built the X-1800 had a displacement of 2600 cu. in. The third engine was the H-3130 an H-24 sleeve-valve design of 3130 cu. in.displacement . This engine came about because it was thought that building two completely different designs was an inefficient use of resources. As built it had a displacement of 3730 cu. in. but the H-3130 designation was retained.
 
The H-3130 was run during 1938 as experimental engine X-86. It was later rebuilt with bigger cylinders as the H-3730 and tested in 1940 as experimental engine X-97. I don't know were the H-2600 falls in the time line. It was an army engine and the other two were navy engines.
 
Which design was proposed first, and what roles were the XH-3130/3730 designed for?

What were they designed for? Aircraft that required engines.

They were deiberately designed to be narrow and to be able to mounted with cylinders vertical or horizaontal, to suit single engine types (vertical) and multi-engine types (horizontal).

The X-1800 was the first choice engine for the R-40C program.
 
Shortround6 said:
The H-3130 was run during 1938 as experimental engine X-86.
Okay
It was later rebuilt with bigger cylinders as the H-3730 and tested in 1940 as experimental engine X-97.
I don't know were the H-2600 falls in the time line. It was an army engine and the other two were navy engines.
For some reason, I thought they were both US Navy engines.

wuzak said:
What were they designed for? Aircraft that required engines.
I was thinking fighters, bombers, patrol planes, etc...
They were deiberately designed to be narrow and to be able to mounted with cylinders vertical or horizaontal, to suit single engine types (vertical) and multi-engine types (horizontal).
So they could be mounted in a skinny or wide layout without issue?
 
So they could be mounted in a skinny or wide layout without issue?

The idea was that the horizontal mounting would be enable the engine to be enclosed in the wing or, at least, present no more frontal area than the wing profile behind it for a nacelle mounted engine.

This was at a time that the USAAC preferred engines that could fit inside the wing of a multi-engine aircraft so that there was minimum disruption to the airflow.

This is also why the Continental O-1430 (later changed the I-1430/IV-1430) and the Lycoming O-1230 (later to be doubled to create the H-2470) were opposed engines.
 
Yep. They are all aircraft that require engines.
True, but bombers tend to require bigger engines :)
The idea was that the horizontal mounting would be enable the engine to be enclosed in the wing or, at least, present no more frontal area than the wing profile behind it for a nacelle mounted engine.
I thought by around 1938 they gave up on the idea of the O-1230/1430 and decided to reconfigure it into the IV-1430.

I'm curious why they asked Pratt & Whitney to develop this design when they had the IV-1430 and O-1230 which could both be doubled up into the IV-2860 and H-2470?

Consider that...
  • The USAAC asked Allison to produce the X-3420 (later V-3420) out of 2 x V-1710's
  • The USN asked Lycoming to take the O-1230 and double it up into the H-2470
  • The USAAC & USN could have teamed up to cosponsor the H-2470 as they did with the V-1710
 
True, but bombers tend to require bigger engines :)

Or more of them.

The B-17 used engines that saw service in versions of the P-36 and F4F, some others as well, probably.
The B-24 used engines that were in the P-36, P-35, P-43, F4F and others.
The Merlin was used in fighters, as well as the Lancaster, Halifax, Wellington, Mosquito, Whitley bombers.


I thought by around 1938 they gave up on the idea of the O-1230/1430 and decided to reconfigure it into the IV-1430.

Not exactly sure when that was changed.


I'm curious why they asked Pratt & Whitney to develop this design

Not sure that the USAAC asked them to design anything.

I believe it was George Mead that had pushed for the development of the sleeve valve engines, after visiting the UK to check out the latest developments in aero engines over there. He was highly impressed with the Napier Sabre, which was then under development.


when they had the IV-1430 and O-1230 which could both be doubled up into the IV-2860 and H-2470?

Consider that...
  • The USAAC asked Allison to produce the X-3420 (later V-3420) out of 2 x V-1710's
  • The USN asked Lycoming to take the O-1230 and double it up into the H-2470
  • The USAAC & USN could have teamed up to cosponsor the H-2470 as they did with the V-1710

I think you mean the O-1430, not the IV 1430.

Not sure where the idea for the H-2470 came from, possibly from Lycoming themselves. It was clear the buried engine mounting gave little benefit over a conventional nacelle mounted engine, and that 1230 was too small for the aircraft in development.

Note that the O-1230 was a private venture engine, and the H-2470 may have well been too, at least initially. At some stage the USN did start sponsoring the program, no doubt after Lycoming pitched the idea.

The 1430 had already been enlarged from just over 1000ci, and was projected to give the same power, or more, as the V-1710. The thinking must have been towards the 1,500-2,000hp class engines.

And yes, the USAAC pushed Allison for an X-3420 engine to give the power they needed for their huge XBLR-1 (XB-15) and XBLR-2 (XB-19) bomber programs.
 
wuzak said:
Or more of them.
True
Not exactly sure when that was changed.
According to Wikipedia (yes I know that mostly invalidates what I'm going to write): "Continental built the first I-1430 engine in 1938 and successfully tested it in 1939"
Not sure that the USAAC asked them to design anything.
It might very well have been an unsolicited contender, but the Army seemed to fund it...
I believe it was George Mead that had pushed for the development of the sleeve valve engines
Which lead to the H-3130?
I think you mean the O-1430, not the IV 1430.
The hyper-engine was the O-1430 which then became the XI-1430. The H-2470 was based on the Lycoming O-1230.
Not sure where the idea for the H-2470 came from
According to Wikipedia...
"It was apparent that the O-1230 engine was uncompetitive with the high-performance air-cooled engines that were then becoming available. The US Navy began funding the development of the Lycoming engine. The funding enabled Lycoming's engineers to attempt rescuing the design by proposing a 24-cylinder H-configuration engine made by stacking two of the O-1230 engines, gearing them together to one common output shaft. The new engine was the H-2470. It weighed in at 2,430 pounds and produced 2,300 hp (1,700 kW) at 3,300 rpm."
At some stage the USN did start sponsoring the program, no doubt after Lycoming pitched the idea.
Was the V-1710 submitted first to the USAAC or vice-versa?
 
Does anybody have dimensions (other than displacement figures) for the X-1800/XH-2600, and H-2470 including...
  • Length
  • Width
  • Depth
  • Bore & Stroke (if possible)
as well as weight?

I have the displacement figures (far as I know) for both (XH-2600: 2597.7 in^3; H-2470: 2467.8 in^3).
 
Did you try wiki as a starting point?

Also, both Pratt and Whitney and Lycoming still exist. Maybe they have historical societies like the RRHT.
 
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I did, it didn't have a complete listing for dimensions.

I got a "Permission Denied" on that site. Can you do a screen-cap?

Strange. The links work for me.

Try the attached images...

I46.jpg
I47.jpg
 

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