US Army Hyper Engine

[Zipper730]

A little project called the Double Wasp. Hard to argue with the decision.

So it was either the H-2240/H-2600 or the R-2800? That seems like a no-brainer...

That said, I do remember some plans for a few aircraft such as the XP-49 and XP-54 that used it

 

[Shortround6]

X-1800/
XH-2600

1 built and running in 1940. Expected entry into service in 1942, Power was not developing as projected. Program stopped in 1940 and P & W concentrated on air cooled engines.
Work started on the R-4360 28 cylinder radial in the fall of 1940 as P & E thought they might get it into service in the upcoming war. They were not sure they could do the same with the liquid cooled engines.

 

[Zipper730]

X-1800/XH-2600
View attachment 541306
1 built and running in 1940. Expected entry into service in 1942, Power was not developing as projected. Program stopped in 1940 and P & W concentrated on air cooled engines.

So the program continued on inertia into 1942, but was effectively dead in the water otherwise?

Work started on the R-4360 28 cylinder radial in the fall of 1940 as P & E thought they might get it into service in the upcoming war.

Which they actually did. As for the R-4360, if I recall, the cancellation of the XH-3130/3730 was the reason they started this design. I could be wrong, but when did the XH-3130/3730 start?

 

[Shortround6]

So the program continued on inertia into 1942, but was effectively dead in the water otherwise?

No, the expected entry into service was established well before 1940. When the program ran into difficulties and P&W realized they weren't likely to meet the expected deadlines they dropped the whole project.

A lot of these high powered engines were a lot more difficult to design and build that was originally thought.

 

[Zipper730]

No, the expected entry into service was established well before 1940.

You said projected entry date was 1942...

Regardless, the engine development started around 1938?

When the program ran into difficulties and P&W realized they weren't likely to meet the expected deadlines they dropped the whole project. . . . A lot of these high powered engines were a lot more difficult to design and build that was originally thought.

Just out of curiosity, in what ways?

 

[Jugman]

The X-1800 stands for Experimental 1800hp. It started life as a 1800hp "H" engine the same size as the Sabre. P&W raised their hp goal to 2000hp and the size to 2600 early in the projects life. The H-2600 was ultimately canceled because it was felt that their efforts would be better spent on developing a larger radial. The R-4360.

 

[Zipper730]

The X-1800 stands for Experimental 1800hp. It started life as a 1800hp "H" engine the same size as the Sabre. P&W raised their hp goal to 2000hp and the size to 2600 early in the projects life.

The proportions add up pretty close.

The H-2600 was ultimately canceled because it was felt that their efforts would be better spent on developing a larger radial. The R-4360.

Technically there was the X-1800/X-2240/2600, and then the H-3130/3730, which I'm not sure how much later development started. I'm guessing the R-2800 proved able to do what the H-2240/2600 could, and the R-4360 could do what the H-3130/3730.

 

[Shortround6]

Most of the large multi-cylinder engines (more than 18 cylinders) went nowhere with only a few 24 cylinder engines being an exception. Reviews are mixed on the R-4360, it was always a bear for maintenance and may have been one of P&W least reliable engines. Not that major parts broke, but a host of minor issues. It should have been simple, take a bunch of R-2800 cylinders (heads, valves, rocker arms, pistons, rings etc) and instead of two rows of 9 use four rows of 7. And yet it took about 3 times the amount of money to develop the R-4360 as it did the R-2800. They had 3500 hours of run time in testing on the prototype and development engines of the "A" series R-2800 before the engine passed it's 150 hr type test. The R-4360 had 15,000 hours on 23 engines before it became "reliable", a condition that might be argued by many early crew chiefs and mechanics.
The cost of the Sabre in either man hours or money has never been revealed.

 

[pbehn]

The cost of the Sabre in either man hours or money has never been revealed.

Most of it down to Napier being Napier, RR managed to produce the Eagle which was almost the same without the dramas.

 

[johnbr]

This is pw-r-4360 no-1.

 

[TheMadPenguin]

Frankly we should create an engine page just of all the engine concepts that were up in the air during this period... this is one from Packard btw

StatsAllPackardAero.pdf

"up in the air"... lol
And the ones that didn't make it off the ground (or design table) to compare what was rejected vs what worked...

 

[Shortround6]

Most of it down to Napier being Napier, RR managed to produce the Eagle which was almost the same without the dramas.

I am not sure the cost, at least of the R & D of the Hercules or the rest of the Bristol sleeve valve engines has ever been revealed, Would Love to be proven wrong on this.

 

[pbehn]

I am not sure the cost, at least of the R & D of the Hercules or the rest of the Bristol sleeve valve engines has ever been revealed, Would Love to be proven wrong on this.

From what I remember reading (something linked from here) the problem wasn't Napier being unable to produce a reliable engine it was unable to produce lots of them. They were capable of constantly increasing power output on a few hand built motors and even pass reliability tests. However mass producing the sleeves, valves etc was beyond them.

 

[TheMadPenguin]

There were all kinds of theories as to what efficient aircraft should look like in the 30s. including
View attachment 541016

What aircraft is this?

 

[swampyankee]

What aircraft is this?

One of Burnelli's designs, possibly the UB-20