A better Armstrong Whitworth Whitley

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marathag said:
R-R also had to forget a lot of the Ramp Head Merlin too. X Blocks always seemed to be troublesome.
Just a bigger V-12 would have been better for making 2000hp, reliably
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Except a 2000 hp engine running on 87 octane gas would have to be around 54 liters.
Except that a 54 liter V-12 cannot run at 3000rpm for several reasons. Like the rate of fuel burn inside of such large cylinders. 4.5 liter cylinders anyone?
A Mikulin AM-35 was only 46.7 liters.
 
When it comes to making a better Whitley we need to put our minds into a 1939 view. A better engine, the Merlin, had already replaced the Armstrong Siddeley Tiger. The Rolls Royce Vulture had first run two years ago and the Avro Manchester flown in 1939 as was the Short Stirling. The Merlin Whitley was intended as an interim until the 2,000bhp engines took over the bomber power fleet in purpose built heavy bombers. In the expected world the Whitley would soon leave production and Armstrong Whitworth to be replaced by Afro Manchesters on the production line.

There was no place for a better Whitley. Replacing the Tigers with Merlins and adding a 4 gun powered rear turret was as far as it was going to go. That was the better Whitley. As it happens that expected future predicated upon successful Vultures never came to be and the Whitley soldiered on with minor role changes until heavy bombers all went the lesser 4 engined route with Merlins and Hercules and Armstrong Whitworth applied it's metal skills to Avro Lancaster production.

That solution proved very successful and a better (insert 1939 preferred heavy bomber) substantial update would be better applied to Vickers with the Warwick as they are stuck with the geodesic frame and not set up for conventional metalwork.
 
It is very easy with the benefit of 80 years hindsight to say RR should have stuck to what they were experienced with (20 odd years of V12 water/glycol cooled engines) and not waste their time on all the radical (or wacko) designs like using steam cooling (after all a radiator is a far smaller target than the whole wing leading edge and therefore the steam has a far greater chance of leaking when shot at). That would have had the Griffin in service somewhat sooner but may have doomed it as the design defects learned from the Goshawk and Vulture may have been designed in to early Griffins or maybe even early Merlins.

The reality is they, like everyone else of the time, were reacting to the latest science of the day that said these things were not only possible but highly desirable. Look at Pratt and Wright and their products and you will see a similar percentage of failed projects - eg most of the Pratt Hornet engines were never commercial or military successes.
 
Shortround6 said:
Except a 2000 hp engine running on 87 octane gas would have to be around 54 liters.
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The R Racing engine ran 2700HP@3400rpm, 37 liters.
not on 87 Octane of course, but a mix of Acetone, Alcohol, Benzene and Toluene, and a high dose of TEL(4.2cc/gal) and healthy amount of boost for 72" MP
This was for a one hour test.

Before that, used 20%California Gasoline 70% Benzole(mix of Benzene and Toluene) 10% Alcohol and 3.5cc of TEL for 2500HP@3200 with 67" MP
Gasoline got a lot better since 1932, when 87 Octane was introduced to the UK, and all future engine were designed to take advantage of that, and wouldn't need the alcohol for charge cooling as the R needed for thos crazy high power levels.
 
OK, now calculate for 36.3" for the pressure at 16,000ft, to compare to the Merlin III. RR R engine was at sea level.
The 36.3" is the pressure that the 67" supercharger at sea level will give you 16,000ft.
Then drop the RPM to level that would be acceptable for a service engine.
And then allow for the need to use less ignition advance for a service engine (need to idle).
Service Griffon ran at 2750rpm.
The Vulture was an attempt to get big power using 87 octane fuel by using small cylinders and high rpm.
The high rpm proved elusive.
But trying to get big power from a V-12 was going to need better fuel than 87 octane in 1935-38.
 
marathag said:
R-R also had to forget a lot of the Ramp Head Merlin too. X Blocks always seemed to be troublesome.
Just a bigger V-12 would have been better for making 2000hp, reliably
Click to expand...

When the Vulture was expected to be making 1,800hp the Merlin was still only making 1,000hp - 1,200hp.

IF Rolls-Royce could have solved its issues, the Vulture would have been capable of power much greater than 2,000hp given better fuel and improved superchargers, etc.
 

The Vulture ran up to 2,500hp on the test bench, possibly as much as 3,000hp, using 100 octane fuel (probably 100/130) fuel.

The Griffon I, based on the R, was giving about 1,500hp in testing.
 
wuzak said:
IF Rolls-Royce could have solved its issues, the Vulture would have been capable of power much greater than 2,000hp given better fuel and improved superchargers, etc.
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Given enough time, talent and treasure I would have liked to have seen what the Vulture could have become.
yulzari said:
And the Vulture cylinder spacing allowed for the possibility of increasing the bore to Merlin diameter.
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If the 36.7L V-12 Griffon can generate over 2,200 hp, I'd not be surprised to see an enlarged >45L X-24 Vulture exceed 2,800 hp. This would be the most powerful liquid-cooled aero engine of the war. And without the complexities of the Sabre's sleeve valves.
 
wuzak said:
IF Rolls-Royce could have solved its issues, the Vulture would have been capable of power much greater than 2,000hp given better fuel and improved superchargers, etc.
Click to expand...
Given the lack of success that every manufacturer who tried an X-Block, I have my doubts on ever getting a reliable engine
Shortround6 said:
But trying to get big power from a V-12 was going to need better fuel than 87 octane in 1935-38.
Click to expand...

Fuel has always been the limiting factor, the reason that R-R did that witches brew of chemicals in 1931 to get that kind of power.

If 115/145 would have existed in 1931, R-R would have used that fuel to get to 72"MP.

100 Octane gets you to 61"

But all of the Fuel developments were coming out of the USA, despite Ricardo researching it first in the UK.

late 1920s gasoline had Octane under 60 for the straight run fuel from California or Romania, it was lower elsewhere- under 40 for the Pennsylvania Gasoline. So that why the Toluene and other Hydrocarbons were added, to get that effective Octane raised to prevent knock so decent compression ratios could be used. WWI era fuel was equivalent to 40 Octane

USA found that 3cc per gallon of TEL was the same as having the fuel being 50% Benzol, the mix of Benzine and Toluene, but not having the cooling troubles Benzol had when running with Prestone Antifreeze in place of water in liquid cooled engines, and in all aircooled engines, and with carb icing in all engines.

The UK, put most their effort into supercharging, while the US was looking at Turbocharging for high altitude performance, but both needed better fuels
 
marathag said:
Given the lack of success that every manufacturer who tried an X-Block, I have my doubts on ever getting a reliable engine
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Not many tried an X, only Rolls-Royce, as far as I am aware, got one into production.

And Rolls-Royce certainly didn't spend as much time and money on the Vulture as was spent trying to get a reliable production Napier Sabre, nor as much tim eand effort Pratt & Whitney spent on the R-2800 before it went into production.
 

Porsche Type 203 aircooled X-16 Tank Engine
Didn't get sorted out before War's end

EMD 16-338

For US Subs. Not successful.
 
marathag said:
EMD 16-338
View attachment 800714
For US Subs. Not successful.
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The 16-184A engines were noted for their reliable operation and good service life. Some of these engines continued to operate (occasionally) into the year 2000. Approximately 544 16-184A engines were built.
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The 16-184A engine design was used as the basis for the General Motors 16-338 engine built in the late 1940s.
Click to expand...

The 16-338 engines proved somewhat unreliable in service and required excessive maintenance. Some of the 16-338's issues were due to the Navy using standard diesel lubricating oil rather than the special oil specified for use in the engine.
Click to expand...

General Motors / Electro-Motive 16-184 Diesel Engine

The General Motors / Electro-Motive 16-184 was a vertical X-16 marine engine that produced 1,200 hp (895 kW). Because of its stacked cylinder configuration, it was nicknamed a pancake engine.
oldmachinepress.com

So, the predecessor to the 16-338 was a reliable X-16 engine that served for years.
 
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