WW2 without V-1710: options for the Allies?

[Shortround6]

What V8 did the Chrysler XV-2220 put together to make the V-16 ?

None, the engine was designed as a V-16 but with the "back to back" arrangement to help solve torsional vibration problems with the long crankshaft. This was not unheard of as I believe several straight eight racing engines of the 1930s were built the same way, or at least used two 4 cylinder engine blocks with the cam drives (and accessories/super charger) driven from between the blocks. The Crankshaft was also supported by a bearing on each side of the center "section". The Chrysler XV-2220 actually took the power for the propeller from the center of the engine and ran a shaft forward under the front half of the engine to the reduction gears.

See: Chrysler IV-2220 - Wikipedia, the free encyclopedia

It didn't "fly" until 26 July 1945, developing new engines was never as easy or quick as it seemed to start with. Building large low stress engines in the late 20s/early 30s that gave 1/3 -1/2 hp per cu in of displacement wasn't that hard. Trying for 1.0 hp per cu got an awful lot harder.

 

[Shortround6]

A few notes/comments.

1) Chrysler hasd the XV-2220 V-16. It was two V-8's coupled back to back, made 2,500 HP and flew in the XP-47H.

As noted above it doesn't fly until the summer of 1945, Since Chrysler doesn't even put pencil to paper until a few weeks of the Merlin "deal" (summer of 1940) even a much faster development won't do much good. Best estimate might be production examples showing up in the summer of 1943. Given the length and weight of this piece of machinery it WILL NOT substitute for the Allison in any existing airframe.

2) Continental had the IV-1430 V-12 of 1,500 HP.

Continental, due to poor Government funding, doesn't build the first 12 cylinder engine until 1939. A number of single and two cylinder test rigs up until then. It doesn't get or even aim for 1500hp until well after 1940. And it needs a turbo to even attempt 1500-1600hp. It does no good for the P-38,P-39, P-40.

4) Lycoming had the O-1230 flat-12 of 1,000 HP. Not sure if this could have been made into a 1,500 +HP class engine.

It is rather doubtful. It was rated at 1200hp for take off and at altitude with a Turbo. Without turbo and using a supercharger that is NOT sea level rated it may be stuck at 1150-1200hp even with 100/130 fuel. It is longer than the Allison even if bent and weighs just as much.

5) Lycoming also had the XH-2470 of 2,300 HP. This was two O-1230 engine mounted sude by side vertically driving a single gearbox.

It also weighed about 2400lbs, No substitute for the Allison in existing airframes. It was also rated at 2300hp for take-off and at 1500ft Military power in low gear of a two speed single stage supercharger, but 1900hp at 15,000ft in high gear. Which gives us 950hp at 15,000ft for the O-1230 or any bent (V or inverted V) versions of it. The XH-2470 is also too late in timing for the critical 1941-42 period of Allison use/deployment.

Or they could have developed an entirely new engine to a specification.

It take usually about 3 years minimum to develop a new engine and sometimes 3 years for a major modification of an existing engine so the Specification needs to be written in 1938 or so to have any effect (and actually 1937 or before to affect the 3 P-38, P-39 and P-40) .

A little more time line on the two hyper engines. The Lycoming, in spite of starting later and due in part to Lycoming sinking over 1/2 million dollars of their own money into the project advanced faster and in 1937 passed a 50 hour 1000hp development test was was flying in a a Vultee XA-19A test bed in 1938.

The Continental passes a 1000hp 50hr development test in 1939.

In 1937 the Allison had passed a 1000hp 150hour type test. and yet still had problems in the summer of 1940 at 1040-1090hp at altitude.

 

[Balljoint]

On the other hand, once the war is won who wants a 'made in America' Rolls Royce? I think it was tried once and no-one bought them!

I recall reading somewhere that the Merlin royalty got to be rather substantial. Of course, once the war was won the surplus supply would have swamped what demand remained. Still the Allison P-82 still didn't have the high altitude performance of the Merlin version.

 

[Shortround6]

I believe he is referring to to a car operation that was set up in 1921 in Springfield MA, and lasted until 1931. One source says that 1243 cars were built from 1926 through 1931 which is hardly "nobody bought them" for a car that could cost as much as $18,000 at the time. Many luxury car makers didn't make it through the depression.

>From Rolls-Royces own web site; " Rolls-Royce of America Inc. manufactured nearly 3000 Silver Ghosts and Phantoms before succumbing to the Depression."<

 

[wuzak]

Just to add to what Shortround said:

1) Chrysler hasd the XV-2220 V-16. It was two V-8's coupled back to back, made 2,500 HP and flew in the XP-47H.

The IV-2220 V-16 was about 40" longer than the Rolls-Royce Griffon, which was of similar capacity and power. The Chrysler also weighed as much, or more.

Honestly, the reduced frontal area afforded by the IV-2220 was wasted in a P-47 - may have well used the H-2470 (but thta had been cancelled by then).

2) Continental had the IV-1430 V-12 of 1,500 HP.

I read once (I think it was in a Graham White book) that Continental spent more time on single cylinder development than Rolls-Royce spent on developing the Merlin to production.

In any case, when flown in the XP-49 and XP-67 it maybe made 1050hp. As the story has it, the McDonnell test pilot deliberately over-speeded the engines to destroy them. Also lost the XP-67 prototype in the subsequent fire.

There are claims that in late war testing the IV-1430 was able to make over 2200hp.

3) Continental had the V-1790 V-12. Early power was just over 700 HP and they didn;t proceed further with it.

That would seem to be a tank engine? Substantially heavier than a Merlin or Allison without a supercharger.

4) Lycoming had the O-1230 flat-12 of 1,000 HP. Not sure if this could have been made into a 1,500 +HP class engine.

5) Lycoming also had the XH-2470 of 2,300 HP. This was two O-1230 engine mounted sude by side vertically driving a single gearbox.

Maybe it could have made 1500hp. At the same stage Merlins would be making 2000-2200hp on the same fuels.

I think it was Lycoming themselves that came to the conclusion that the O-1230 wasn't big enough or powerful enough for modern aircraft. So they doubled it.

It was a troubled engine program, and was cancelled mid war.

As SR says, not a substitute for a V-1710, but possibly could have worked for the P-47 (instead of the Chrysler).

 

[Shortround6]

The IV-2220 V-16 was about 40" longer than the Rolls-Royce Griffon, which was of similar capacity and power. The Chrysler also weighed as much, or more.

Yes, the Chrysler was more a replacement for the R-2800 or R-3350 than for the Allison.

I read once (I think it was in a Graham White book) that Continental spent more time on single cylinder development than Rolls-Royce spent on developing the Merlin to production.

Not really Continental's fault. They were acting like a prototype shop for Wright Field who was dictating the design features and pace of development. Continental put little if any of their own money in the design and only completed projects, steps as the Army issued new contracts and paid for them. A very high degree of micro management.

That would seem to be a tank engine? Substantially heavier than a Merlin or Allison without a supercharger.

Got that right, it was an air-cooled engine. 2332 pounds dry, first used in the T-30 Heavy tank which showed up at Aberdeen Proving ground in April of 1948, Hardly an Allison substitute pre-WW II or in the early years. This version was gasoline fueled, later versions were converted to diesel and powered quite a number of US tanks.

 

[wuzak]

Other types of US LC engines under development before or during the war were:

Wright R-2160 Tornado
Pratt Whitney X-1800
Pratt Whitney XH-3130/XH-3730
Lycoming XR-7755

None of which could serve as a V-1710 replacement.

 

[GregP]

Hey guys,

The Allison V-1710 was designed in 1929 and was running in 1930. If it had failed, there was PLENTY of time for alternate designs. Where the hell are you guys coming from?

The XA-11 flew in 1936. Had it not worked, what exactly do you think they would have been doing for the next 5 years? Knitting? The Bf 109 flew in 1935 with a Rolls-Royce engine and then went through a Jumo until the DB was ready, and went to war before 1940. Are we too stupid to DO that? Right ...

Saying it took years is RIGHT ... and we would have HAD years unless we did nothing when the Allison failed. I rather think it would have been noticed and a reaction would have been forthcoming on an alternate engine or three.

You are free to characterize us as people of non-action at the time, but I might remind you that BMW started out producing radials of US design, as did the Japanese. If the Allison had failed, there would have been a replacement coming along. Bet on it.

 

[nuuumannn]

In any case, we would have developed an American engine for our planes before adopting the Merlin unless wartime expediency had required we use Merlins. That could have been the case if the allisons had failed.

I agree with you there, Greg, but I don't necessarily agree that a foreign engine, such as the Merlin would not have been bought if a suitable American alternative could not be found in peacetime. There are a number of examples in aviation alone where foreign technology has been adopted by the USA outside of WW2; the Airco D.H.9, the Fokker F-VIIb, the English Electric Canberra and the Hawker Siddeley Harrier for example. Using the F-VIIb trimotor as a point, as a result of this aeroplane, trimotors became the configuration of choice for airline manufacturers and operators alike and it wasn't until the death of Knute Rockne in a F-VIIb that the trimotor fell out of favour and arguably led directly to the Boeing 247 and Douglas DC-1.

The argument that because American aircraft didn't use Merlins in large quantities is evidence that they would not have if there was no alternative is flawed; all it does is demonstrate that the USA had alternatives of its own and did not require a foreign engine. Sure, I can see the isolationist stance pre-war, but historical precedent dictates that if America has a need for something and it cannot produce it at home, it will go abroad if need be.

The thing with this particular 'what if' scenario is that stating that the USA would definitely not get a foreign engine is as unknown as predicting that it definitely would. Evidence eixsts to prove that the USA might if it had to. But, yes, I agree; a home grown alternative would be examined and pursued.

 

[wuzak]

Hey guys,

The Allison V-1710 was designed in 1929 and was running in 1930. If it had failed, there was PLENTY of time for alternate designs. Where the hell are you guys coming from?

The V-1710 was only delivered in small numbers by the outbreak of war in Europe (1939).

It was still being tweaked here and there.

Another poster suggested that Allison's finances weren't looking too clever in the late 1930s. Possibly Allison could have folded if not for GM's support.

Saying it took years is RIGHT ... and we would have HAD years unless we did nothing when the Allison failed. I rather think it would have been noticed and a reaction would have been forthcoming on an alternate engine or three.

The IV-1430 was started at a similar time as the V-1710 (~ '30/'31), yet failed late in the war ~'43/'44.

Just because it was running before then doesn't mean it is going to be a success.

 

[GregP]

Allison COULD have failed, true. Some engines DID fail. But saying we could not come up with an alternative V-12 or V-16 is ludicrous.

The Allison completed its US 150-hour type test in April 1937. The Merlin didn't.

At the end of the war, an overhaul a Merlin took the USAAF an average of 320 hours. An Allison overhaul took and average 191 hours. Source: Army Air Forces in World War II

In American service the Merlin rarely got more hours before TBO than the Allison. Can't say what the Birtish or Russian got. Source: WWII overhaulers visiting the Planes of Fame. Can't vouch for or refute what they said, but DID work for a shop overhauling ALlison for 1.5 years. We had ALlisons out tgehre FLYING with 1,100+ hours on them and still running strong. I have seen Merlins fail at 25 hours ... but have also seen ONE Allison come in with low oil pressure at 250 hours.

Turned out it was flogged at an airshow abd 60 inches of boost with only 2.5 hours on the engine. The oil pressure waws within spec, but lowered than before the aerobatic flight. We attributed this to inadequate break-in. When reworked (not repaired ... the oil pressure was still within spec) and broken in properly (under warranty despite the abuse), the engine is NOW flying fine many hundreds of hours later with no trouble.

There is nothing wrong with the Allison that the USAAF didnlt require. Allison twice offerd to make ot a 2-stage supercharged wngine and was turned down by the USAAF. Finally they allowed Allison to produce an auxiliary supercharger, but a 2-stage, engine-mounted unit similar to the 2-stage Merlin would have been both lighter and better.

 

[bob44]

Hey guys,

The Allison V-1710 was designed in 1929 and was running in 1930. If it had failed, there was PLENTY of time for alternate designs.

Yes, if the Allison would have been a total failure, it should have been realised well before the start of the war in Europe.
Giving time to make it right, or the possibilities of developing another inline or adapting a foreign design.

 

[Shortround6]

As I have said before in this "what If" When the Allison fails to show up is critical.

Fails to be invented/designed in 1930-34 is one thing, plenty of time to come up with an alternative.
1935-37 things get a little dicier.
Allison is being developed and then turns to crap in 1938-39? Things get a lot more difficult for the US.
Allison does everything just as done Historically but can only build 11,500 engines in 1942 ( which still ten times what they built in 1940) instead of 14,900 leaving the US 3400 engines short? what is the US alternative?

Please remember that the Army paid for a NEW factory to build Continental I-1430s. The Factory wound up building P W R-1340s for several years and then switched to building Merlins in 1944. So things did not always go according to plan.

It turned out that the Allison was a better basic engine than the Merlin but that was by NO MEANS a known fact even in the summer of 1940. By the summer of 1940 3-4000 Merlins had been built compared to under 200 Allisons and the Allison's being built had to be operated at reduced power until they could be reworked.

Telling us how great Allisons are NOW is a waste of space. Most Allisons flying now use either the 12 counterweight crank or late production 6 counterweight cranks don't they? By 1942 Allison crankshafts were both shot peened and nitrided which add tremendously to their life over the crankshafts being produced in 1940. The basic block castings were also strengthened and even the casting process was changed to increase strength and reduce the scrap rate. Allison got rid of the early reduction gear (long nose) used on ALL early P-40 engines because it was a weak point (and they had been told so before it went into production).

The Allison was a very good design and the Allison company (and GM) deserve great praise for both building it in the quantities they did and in improving the basic engine so the later ones were so much better than the early ones ( but don't forget that both P &W and Wright were also improving their engines).
This doesn't change the FACTS that a number of the alternative engines were problematic and had built in flaws that could NOT be gotten rid of without MAJOR redesign and time. In fact it just helps point out how lucky/skilled/smart the Allison design team was.

As far as the US not using British designed engines? How many US Jets used British designed (or based) engines from 1945-1960 and beyond?

 

[GregP]

Your post is a waste of space to me, but that's not a challenge to a fight, it is a simple retort to your words.

Passing the type test IS military acceptance of the design. It could NOT have failed in 1938 - 1939. It could have failed in April 1936 but didn't.

We're talking piston engines in WWII, not post-war cooperation on jets after we won a world war together, defeating the most powerful enemy ever created to date.

BIG difference in attitudes and possibilities. By 1940, all that was needed was more Allisons with some inevitable development associated with ALL piston engines of WWII. I just wish the development had included a government-funded, 2-stage, integral supercharger ... but it didn't. That's life. By the end of the war, the HP from a Merlin or an Allison was formidable.

Ah well, therein lies a tale of it's own.

 

[wuzak]

Greg, you have to admit that, V-1710 aside, the development of liquid cooled engines in the US proved to be problematic.

None of them came to an acceptable standard.

btw, while the Merlin didn't complete the US 150 hour test in 1937 it didn't really have to. It was subjected to, and passed, the British equivalent (the 114 hour type test). Not sure when it first did that, though.

 

[gjs238]

13,708 Merlin-powered P-51's counting the two conversions from P-51A to P-51B.

So, if the V-1710 was a failure, and there was no Mustang, then what would have become of those 13,708 Merlins?

 

[Shortround6]

Your post is a waste of space to me, but that's not a challenge to a fight, it is a simple retort to your words.

Nobody is debating if the Allison or Merlin is the better engine today or even which was the better engine in 1942.

Passing the type test IS military acceptance of the design. It could NOT have failed in 1938 - 1939. It could have failed in April 1936 but didn't.

Really? Jumo 222 passed a type test, R-R Vulture passed a type test, Napair Sabre passed a type test, Wright R-3350 passed a type test. None were anywhere near ready for squadron service. Production Allison's in 1940 were operated a higher power level than the V-1710 that passed the type test in April 1937.
Engine that passed the Type test in April 1937 was rated at 1000hp/2600rpm/40 in for take-off and 1000hp/2600rpm/40 in at sea level military power. Engines in production in the Summer of 1940 were rated at 1040hp/3000rpm/42in for take-off and 1040hp/3000rpm/14,300ft /41in? Military power. But hey, whats an extra 400rpm on a 1937-40 aircraft engine, right?
The 1040hp engine used in the P-40s took 7 tries and 5 engines to pass it's 150 hour model test. It didn't pass until August 1940. The engines already built were restricted to 950hp at 2770rpm for take-off, 950hp at 2770 rpm for Military power to 8,000ft and 838 hp at 2600rpm to 8,000 until brought back to the Allison Factory and re-worked.
Please note that the V-1710-33 engine used in the early P-40s didn't pass it's model test until a point in time about 1/2 way BETWEEN initial talks Between the US, Britain, Ford/Packard and Packard signing the agreement.

Allison's success was by no means a sure thing in 1940 let alone 1937. The US was fortunate that Allison's people were as good as they were and they were able to Bring the Allison along as they did, meeting and exceeding the challenges they met on the way.

 

[Shortround6]

There are "type" test and "model" tests, which sometimes overlap. A "type" test is often done by a government body (Army/Navy/National aeronautics board, etc) Model tests are often done by the manufacturer but may have "observers" from the customer or regulating agency in attendance. Corrections welcome on this.

The engine has to pass a "type" test to be 'accepted' and/or be declared "airworthy". Governing bodies can decide if engines with modifications/changes can operate on the basis of the original "type" test or if a new test is needed, changes in rated power levels would usually require a new test, changing the carburetor or magneto or something like probably wouldn't. WEP settings don't require a full 100/114/150 hour test. They do require a certain amount of time be spent at the WEP settings ( for the US that was 7 1/2 hours total at the WEP power level but done 5 min at a time with cool down periods between each "burst".

The Merlin did "fail" it's US type test which was run between August 12, 1941 and Nov 1 1941 and included a 20hr penalty run over and above the 150hr test. The engine did complete the 150 hours but on tear down was found to have 3 cracked pistons, chrome plating coming off the cam followers, worn impeller shaft, sheared rivets in the supercharger clutch plates and a few other problems. Due to the war situation it was decided to "pass" the Merlin. The Allison's tested in 1939-40 "might" have passed a "relaxed" test but out of the 5 engines at least one broke a crankshaft and another (or 2?) cracked a block. Engine that passed had a crack in the cylinder head cooling passage.

Building high powered aircraft engines was not an easy thing. These engines had power to weight ratios comparable to or exceeding many race car engines of the day and were built in large quantities instead of handfuls and were required to last much, much longer than the race car engines.

 

[gjs238]

In the absence of the V-1710, wonder if a "new" R-1830 powered fighter would have been viable.
At least until the R-2800 powered fighters came online.
Such a beautiful job was done on the P-51, wonder what those boys could have done with the R-1830.

 

[Shortround6]

Again, we have a moving "target" or moving "base line".

In the Spring of 1939 the XP-40 demonstrated 22% less drag than the P-36 and since the XP-40 was the 10th production P-36 airframe we can assume the differences aside from the engine were pretty minimal. By late 1942 P&W had gotten the drag difference down to about 8% on the factory test mule pictured earlier. And/or done a better job of using exhaust thrust? Better radial installations were done but they come even later.

What kind of radial installation can you get (reasonably expect) in 1940-41 for the R-1830? somewhere in between 8 and 22% more drag than the Allison? assuming that the engine/radiator installations on the XP-40 and Allison P-51s were equal. If the P-51 installation is better that leaves the radial with further to catch up. An R-1830 powered Mustang may be a much faster plane than a P-36 but that does NOT mean it was up to world standard in 1942.