July 1st 1937: your own USAAC/USAAF/USAF?

[tomo pauk]

Perhaps but a "what if" that has the time-traveler arriving in 1937 (or any other year) to make decisions based not only a general knowledge of history but having a computer full of aeronautical and engine knowledge (airfoils, high lift devices, structures, windtunnel tests, foundry practices, advanced heat treatment and so on and so on) distorts things rather quickly.

Fair enough.
The person with a decent knowledge about history of US aviation will know that NACA is the best start when it comes down to aerodynamics, but people back then knew that already. He will also know that (not only) turbo R-2800 was a solid and useful piece of machinery.

Does it? Without turbos you are actually comparing a 1500hp radial at FTL to a 1150 V-12 at FTL with the FTL's only a few thousand feet apart. And in 1939-40 the Army does not know with 100% certainty that the big radial can be successfully turbo charged. This was reason the Army was developing the Allison and the two Hyper engines, the "wisdom" of the mid 1930s was that the air-cooled engines could not stand up to the needs (cooling) of being turbo charged at high altitudes. By 1940/41 the radials had grown a lot more fin area per cylinder, baffling and cowls got a lot better and the radials (with one exception) turned out to handle the problem pretty well.

Unfortunately, the Army thought they are better in engine design than the companies who were in the engine business.
The 'big radial' means 'radial with plenty of cylinders' - 14 or 18? Wonder why it was deemed that a radial wit 18 cylinders will be harder to turbocharge than a radial with 9 cylinders? Not trying to be too harsh or rude, just wonder.

Without dictatorial powers the 'time-traveler' isn't going to get the army to buy a new 2400hp bomber (they already have the B-18 and/or the Lockheed Hudson) or a liquid cooled "attack" machine. And they Already have the Airacuda in progress to "show" what kind of performance might be expected.

I'm not trying to persuade Army to buy a bomber with half a dozen crew members and trainable 37mm cannons, with people in nacelles, nor conversions of transport aircraft. I'm after a bomber that has no extra fat on the air-frame, that will be using current aerodynamic knowledge.

Chances are slim and none.

As long as Slim is still in the town ...

Everybody wants to use the 'Mosquito' as model while conveniently forgetting the Mosquito was "designed" around a 1000lb bomb load and turned out to perform above expectations. Mosquito also came together with the Merlin 21 engine and NO Mosquito was flown with a lower powered engine.

The Merlin XX and 21 were allowed for 1290 HP for take off; +12 lbs boost. Able to carry 2000 lb bomb load.
Merlin 22 and 23 were allowed for 1400 HP for take off, +14 lbs boost. Capable to carry a 4000 lb cookie. The 1600 HP for take off, +18 lbs boost, was allowed for Mk. 24, 25, 31 and 33. Up to 5000 lbs + 500 imp gals.
We might also look at Mosquito with 2-stage engines, on 1280 HP for take off, 5000 + 500 as above.
The V-1710 started offering 1325 HP for take off from mid 1942, and, in turbo setup (weight in the ballpark as the 2-stage Merlin) 1425 HP from mid 1943.

I would also note that a B-26B-D can take-off in about the same distance as an A-20 while weighing 5-7000lb more. Yes the B-25 weighs more empty but some of that weight difference in take-off weight is fuel and bombs. Needing two aircraft to deliver the same tonnage of bombs to a target that a single aircraft can doesn't really show much of a savings.

B-25 was one of better uses of the R-2600. Perhaps it was not such a good idea to produce the Martin 'Baltimores' - on same engines, up to 2000 lbs of bombs at 830-1000 miles? Boston IV and V can do 2000 lbs to 1570/1530 miles, or 4000 to 710/690 miles, due to, finally, proper fuel load. Mosquito with 2-stagers can do 1485 miles with 3000 lbs, and that means 2 x 500 lb bombs are under the wing racks. With Merlin 23, 31 or 33, it is 1620 miles for same payload.
All range figures are for max economic speed.
What would be the figures for B-25s?

And here we hit one of my pet peeves with a lot of these "what ifs". "why don't we have air force XXX build airplane YYY with engine QQQ because it will be a fantastic airplane 2 years later when engine ZZZ shows up. Disregarding that plane YYY will be a piece of crap with engine QQQ.

You do have engine ZZZ (= turbo V-1710) before the Germans attack USSR. With engine QQQ (= V-1710-39) it would have engine power comparable with Pe-2, Ju-88A-1/A-5 or Bf-110C, none being regarded as a piece of crap.

 

[rinkol]

Unfortunately, the Army thought they are better in engine design than the companies who were in the engine business.
The 'big radial' means 'radial with plenty of cylinders' - 14 or 18? Wonder why it was deemed that a radial wit 18 cylinders will be harder to turbocharge than a radial with 9 cylinders? Not trying to be too harsh or rude, just wonder.

The 14 and 18 cylinder engines are constructed with two rows of cylinders. It is very reasonable to assume that the second row will present cooling difficulties, particularly in operation at high altitudes with high boost levels. Also, as the number of cylinders per row increases, the space between the cylinders for routing cooling air decreases. It is interesting to note that even under less severe conditions, BMW had problems with the the early versions of the BMW 139/801 and needed a cooling fan to achieve acceptable operational performance. The R-3350 also had cooling issues with the rear row of cylinders. It took a lot of experimentation and engineering effort to come up with workable solutions for these engines.

Aside from these points, it is reasonable to surmise that later improvements in the efficiency of the superchargers and intercoolers helped a bit.

One of the fundamental problems was that there was a widely held preoccupation with the importance of minimizing the drag of engine installations in the late 1930s. This pushed development efforts on the part of the US military towards liquid cooled engines in configurations calculated to facilitate installation within aircraft wings. Similarly, considerable effort was wasted in Germany on surface evaporation cooling and coupled engines. It was only later that the possibilities for minimizing the drag of air cooled engines came to be fully understood.

 

[m37b1]

SOme of your simple changes are not so simple.

Allison needed a LOT more engineers to work on a two stage system, they had the "idea" in 1938 ( about the time P&W filed patents) but their design/engineering staff was way too small. They also had the minor problem of building new factory facilities so they could co form 2-3 engines per month to hundreds of engines a month ( the same design/engineering staff responsible for engine design was also responsible for production tooling design).

Americans need direct fuel injection much less than the British. American Carbs didn't have the "G" problem and later war American carbs were pretty much throttle body fuel injection, Direct fuel injection also calls for hundreds more precision parts per engine.

High powered aircraft diesel engines were a dream.

Allison: I understand the complexities of engineering and production faced by Allison. Hence the FIRST thing I commented on was budgeting (funding), which was lacking early in the 1710's development. If this change in direction had been implemented in 1937, I don't think it's outlandish to believe that they would have had a decent supercharger ironed out by 1940/1941. (BTW, I would not have stopped turbo development).

DI: My goals for DI, were to promote more even distribution of fuel in large engines, especially radials. You already know the benefits in reliability and efficiency here.

Diesel: As I stated, a dream. But, so were air-cooled, spark-ignition engines reliably producing 1hp/cubic inch in 1937. A diesel bomber engine was worth perusing in my opinion.

 

[tomo pauk]

...
The Merlin XX and 21 were allowed for 1290 HP for take off; +12 lbs boost. Able to carry 2000 lb bomb load.
Merlin 22 and 23 were allowed for 1400 HP for take off, +14 lbs boost. Capable to carry a 4000 lb cookie. The 1600 HP for take off, +18 lbs boost, was allowed for Mk. 24, 25, 31 and 33. Up to 5000 lbs + 500 imp gals.
We might also look at Mosquito with 2-stage engines, on 1280 HP for take off, 5000 + 500 as above.
The V-1710 started offering 1325 HP for take off from mid 1942, and, in turbo setup (weight in the ballpark as the 2-stage Merlin) 1425 HP from mid 1943.
....

To correct myself a bit:
Different sources state the take off power of the Merlin XX and 21 to be either 1280, 1290, or 1300 HP.
The take off power of the Mk. 22 and 23 was sometimes listed as 1390 HP. Production of the Mk.22 and 23 started some time in 1942? The Mk. 24 and 25 - from 1943?
The Mk. 31 and 33, Packard Merlin, going by the Mosquito B.Mk.XX, were cleared for +14 lbs boost for take off power of 1390 HP, not for +18 lbs = 1610 HP. Still capable to carry 5000 lbs + 500 gals.

 

[tomo pauk]

Some other things: how good would be a bomber with 2 x R-2800, but with a wing that is somewhat thinner, but, initially, of greater span/area (about as big as B-26B, ~660 sq ft, vs. ~600 sq ft of the earlier versions)? With only a tail turret, plus some fixed HMGs, 4 crew members max; plus a better flap system? That is, if there is some R-2800 left once the 4-engined bomber starts to use those

What about a more potent cannons, that would be suitable for some tank busting? Derivative of the 37mm AAA, for the A-20 and the like? Self-loading 57 or 75m, hopefully with muzzle brakes?

 

[gjs238]

In order to move a bit from good old Europe: how should the USAF evolved, if you were in charge from July 1st 1937? You say what airframe, engine, armament and electronics get produced, and how much of it. Plausible stuff, of course
You DON'T say what the USN is going to get, but peeking n their plans might save you a month or two of work in some other project.

Build another R-2800 factory as soon as feasible, similar to how another factory was built to produce P-51's.

 

[Shortround6]

You mean in addition to the Ford plant ( deal signed in Sept 1940 with only 8 R-2800 built by P&W already delivered). Or in addition to Nash-Kelvinator (first 6 engines delivered in Dec 1942) or in addition to the P &W Kansas City plant ( 1st engine Dec 1943) and Chevrolet joined in the summer of 1944.

Something interesting is that while P &W East Hartford ( or Connecticut) made all types of R-2800s ( and 3 major factories were built as satellites to the East Hartford Plant.) Ford built only single stage engines ("A" and "B" series) Nash-Kelvinator built only two stage engines ("B" series), The Kansas City plant built only "C" series Single stage engines and as did Chevrolet. At least through the end of 1944.

Please remember that it could take over year from signing a deal to getting the first engine.

 

[gjs238]

Yes. Tomo and I need more R-2800's for our 4 engine bombers, 2 engine bombers, and Army non-turbocharged fighters
Engine delivery needs to start sooner.

 

[Shortround6]

Betting a lot on a rather unproven engine?



And WHICH R-2800 do you want your NEW factory to build? There weren't a lot of differences between and "A" series and a "B" series singe stage engine but the only thing a "C" series engine shared was the bore and stroke.

AS I mentioned, the deal with Ford was signed with only 8 R-2800s delivered, and was signed about 10 months before the 1st two stage engine was delivered.

And what else doesn't get built?

Maybe you could get either Buick or Chevrolet to build R-2800s instead of R-1830s? Buick built 63,568 R-1830s by the end of 1944 and Chevrolet built 54,647 R-1830s by end of 1944 but since it seems like you are planning on doing away with a large number of B-24s maybe you can get by with a lot fewer R-1830s.

Engine deliveries from existing factories cannot start sooner and even if you sign a "deal" at the same time as Ford for a 3rd source what you are signing is a deal for "A" series engines since the others don't really exist. Tooling up ( and machine tools were scarce and being assigned by priority (rationed if you will) for 'experimental' engines often leads to wasted effort as drawings and some tooling have to be changed for the final/production version.

The design of the "A" series engine was only finalized in Feb 1940 with the "bill of materials" released to production.

P&W themselves were expanding rapidly in 1939-40. The "French" wing of 280,000 sq ft roughly doubled the size of the existing plant and the "British" expansion was another 450,000 sq ft started in June of 1940.

 

[gjs238]

Sometimes I wonder if a new P-51 plant had NOT been built in Dallas, Texas, but someone here on this forum suggested that with hindsight that one should have been built, there would be reasons given why this could not have been done.

 

[Shortround6]

You can build new factories and swap production around, you just have to be aware of what else was going on and what some changes might cost. You also cannot speed things up to a point where you are calling for new factories to be in production (or even finish tooling up) before the home factory really has things figured out.

Fortunately for the US the "Dallas" plant was not built with the intention of building P-51s but of building AT-6 and freeing up the Inglewood plant ( which was expanded) and as work was going on the Dallas plant was expanded also ( B-25 production had been shifted to Kansas City). In fact one account has work starting on the Dallas plant 9/28/40. First Dallas P-51C flies 3 months after first Inglewood P-51B. Please also note that the P-51-B was first ordered (400) on the basis of the manufactures "estimate" of performance 3-4 months before the XP-51B flew and it still took 9 months to get a production plane to fly.

Limitations on machine tools, raw materials and even steel I beams were all too common during the war and allocations were being made months in advance. P&W Kansas city plant was delayed over 6 weeks going into production because 6 specialty grinders were re-allocated to Napier to help with sleeve production for the Sabre ( and shipped on the Queen Mary rather than slow freighter). This may have cost several hundred engines.

 

[gjs238]

Great info!
Especially about tooling being diverted into the Napier black hole.
Again with hindsight, we're better off putting our resources into our strengths - the R-2800.

 

[Shortround6]

A big part of the US ( and other countries) problems were budgets. The US didn't increase military spending anywhere near what the European countries did in the late 30s. The US didn't really open up the spending until 1940.

From J. Baugher's Site: "With the R-1830 engine, the Y1P-36 did so well that it won a 1937 Army competition, and on July 7, 1937, the Army ordered 210 P-36As, the largest single US military aircraft order since the First World War. "

This is about a year after the both the Hurricane and Spitfire were being ordered in quantities far exceeding the order for P-36s.

It is also this order for P-36s that helped cement the order for P-40s in the Spring of 1939 as the P-40 used many of the same parts/components/tooling and ONLY Curtiss had a Factory and work force in place and trained to ensure rapid delivery. Army was in the position of P-40s or nothing going into service in 1940. First P-40 of this Spring of 1939 order was not delivered until June of 1940 and Curtiss managed to deleiver 773 planes by the end of the year, Bell managed to deliver 13 P-39s and Lockheed 1 P-38.

First 6 months of 1941 saw Curtiss building around 150 planes per month (898 planes) while Bell only exceeded 15 planes a month in June (37 planes) and Lockheed never got past 4 P-38s a month at this time.

It is not just a question of picking "winners" but being able fund them (and the engines and the rest of the "stuff" ( guns, radios, oxygen equipment, landing gear etc) and plan for them 2-3 years before they see squadron use.

Things were so tight that the Army, in the spring of 1939, owed Allison over $900,000 and without the order for engines for the P-40 there was a very real possibility that GM would have just shut the engine project down ( GM had loaned Allison about 1/2 million at that point). This also explains why Allison wasn't doing a whole lot of work on two stage superchargers, fuel injection or other advanced projects at the time. The Army never did pay up. They made Allison "forgive" the debt in return for permission to export the engine to France and Britain.
Ford got 14.3 million dollars in Sept 1940 just to build the 2nd source R-2800 plant, that sum didn't cover the cost of a single engine. The Plant was tripled in size from the initial construction to what it was in 1944 also. Initial Ford plant was 889,717 sq ft. By Feb 1 1942 plans were drawn up to expand it to 1,426,525 sq ft, but this was not enough and by the beginning of June 1942 the plan called for 2,618,817 sq ft. Another expansion came later.
Basically the US spent a LOT of 1940 and 1941 building the factories that would produce the aircraft and engines in 1942.

Edit. Please note that Curtiss only got $12,872,898 in April of 1939 for 524 P-40 air frames (no GFE like engines).

The funding of government owned but privately managed plants/factories would have been something of a political hot potato before the shooting started.

 

[gjs238]

Perhaps the New Deal should have concentrated more on military R&D, but as you say, a political hot potato.
I imagine lots of unemployed folks would have loved jobs in the defense industry.

 

[parsifal]

From J. Baugher's Site: "With the R-1830 engine, the Y1P-36 did so well that it won a 1937 Army competition, and on July 7, 1937, the Army ordered 210 P-36As, the largest single US military aircraft order since the First World War. "

I wonder if J baugher is th same as our JoeB......

 

[tomo pauk]

JoeB is Joe Brenan (not sure about the number of 'n' letters in his last name). He (joeB) posts at tank-net forum sometimes, and IIRC there was a person asking him whether he is J. Baugher

 

[tomo pauk]

Not that the USA was devoid of powerful engines, but how about a big V-12, say, a bit above 35 L? Chrysler, Continental and Lycoming can give it a try, the best one gets the contract.

When would be a good time to give the turbo-compound engines a chance?

 

[gjs238]

Some time ago I asked about a "big block" version of the V-1710.
The idea is to try the larger displacement approach like our Teutonic friends.
Wonder if it could have made up for some of the V-1710 shortcomings.

 

[tomo pauk]

Not just Teutonic. The RR Griffon have had the displacement of 2,240 cu in (36.7 L). That, along with moderate RPM (2750), good boost and capable superchargers made it a performer.
The US 'big block' should have no problems beating the V-1710. A single-stage version for the P-51, turbo version for the P-47?

 

[Shortround6]

A lot of things depend on how it is designed. Please remember that the V-1710's only real short coming was the fact that it's supercharger did not keep place with the Merlin's. It started out in 1938/39/early 40 just about as good and then fell behind.
A bigger bore engine is a bit harder to cool. A longer stroke cannot turn quite as high an RPM. The "Teutonic friends" didn't use the boost pressure the Allison did or the rpm.

You can build a "big block" 35 liter engine that weighs the same as a 27 liter engine if you limit the RPM to around 80% of the 27 liter engine and you limit the manifold pressure to the same or lower.
Early Allison in the long nosed P-40 used just about 1.3 Ata for 1090hp at 13,200ft (4000 meters).
The next Allison (p-39 or P-40 D/E) used about 1.48 Ata for 1150hp at 11,700ft (3545 meters) and now the supercharge limitation kicks as the engine would make much more power down low with certain models using 1.9 and even 2.0 Ata.

If you want a "big Block" that turns close to the same RPM and uses the same manifold pressure you get something like the Griffon or part way between the Jumo 211 and 213 or the DB 605 which was around 200lbs heavier than the V-1710.