# XP-65/F7F Development



## Zipper730 (Jan 23, 2017)

I was thinking about a couple of things regarding the XP-65 and the later F7F: I'm not sure if my timeline is right.

From what I remember 

The USN issued a requirement for an interceptor program: This produced the XF5F, XFL-1, and F4U, of which the latter one.
The USAAF procured a long-ranged escort fighter in the form of the XP-65 which was to use 2 x R2600 with either a twin-stage supercharger or turbocharging, a pressurized cockpit, and 37mm cannon; they also procured the XP-50, which was an XF5F with a nose-gear and turobcharging.

The USN issued specifications for a heavy twin-engined naval fighter using 2 x R2800's with superchargers, and cannon armament
The USN & USAAF requirements were joined together.
I know the designs were eventually so different that Grumman was unwilling to pursue both, and decided to just develop the USN design, which became the F7F Tigercat.

What I'm curious about is the following

Why didn't they just use R-2800's with either 1 stage supercharging (F7F), or two-stage supercharging, or a turbocharger?
Why did the USAAF want 37mm cannon: They were brutal when they hit, but fired slowly, had bad ballistics, and permited only 40-45 rounds; the 20mm hit greatly harder than the 50 calibur, had similar refire rate, ballistics were a little inferior but acceptable at 400-yards for most purposes
Why did the USN just put 4 x 20mm in the nose and disregard the 0.50? That was more than enough...


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## wuzak (Jan 24, 2017)

Regarding the engines, the project timing probably didn't allow consideration of the R-2800.

According to this, the project started in 1939. At which point the R-2800 was still relatively early in development, while the R-2600 was in production.

The XF6F also used an R-2600.

As for the guns, the aircraft was to shoot bombers down. So the more guns the merrier.

The USAAC/F did have a fascination with the 37mm cannon. Probably because of its destructive power.


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## GregP (Jan 24, 2017)

You are asking questions that I doubt younger people can answer. There are a few in here who stubbornly think the U.S.A. should have bought foreign weapons, particularly the DH Mosquito.

But the attitudes of the time would preclude that from ever happening at the time when it might have been really useful. That being said, even if we could post the real-world reasons for the items above, very few people today would accept the reasoning behind them. Everyone wants to take apart the decisions and replace them with whatever decision seems best using the infallible power of hind-sight and knowledge of everything we know today after years of digging and changes in attitudes.

I believe the desire for large cannons was simple: they wanted any hits on a bomber to have maximum stopping power, and didn't really think much about fighter vs. fighter combat. That was a necessary evil for the planners.

Same with the four 20's: Having four 20 mm cannons "fixes" the slow firing cannon issue and allows more hits on bombers.

I seriously doubt anyone in here has detailed knowledge of the number ot turbine wheels that were avilable for use at what time in WWII, and the supply of metals required for the hot section was likely the simple deciding factor. If someone DOES know, maybe they'll share it.

The valves in an Allison were sodium-filled Stellite, and that required tungsten and molybdenum. The supplies weren't unlimited and ALL military piston engines needed valves, so they got first priority for the alloys. Turbine wheels came further down the food chain. Other makers also needed wear-resistant valves, and Allison was forced to share that with Rolls-Royce and, eventually, commerical competitors. That was NOT a welcome decision by Allison or GM, but helped the war effort overall.

I don't know why the engine makers didn't experiment more with 2-stage superchargers, but it most likely is due to their primary customers wanting turbochargers instead. Everyone was sort of waiting for the "breakthough" in turbocharging and it never did get to a stage of development that was as reliable as 2-stage superchargers. I think charge coolers were a big issue: inter / after coolers that could drop the etemperature of the compressed air and/or air/fuel mixture and delay detonation.

If you go look up the history of the R-2800, you will find a LOT of master-rod designs, a lot of failures before "getting it right," a lot of cooling fin designs, and a lot of hard work. Early R-2800s weren't necessarily great engines. The White book, "R-2800 Pratt and Whitney's Dependable Masterpiece" is a great source. The timeline doesn't exactly allow for early use in large numbers. "B series engines were built from 1943 and "C" series were from 1945. An "A" series engine has very few parts in common with an "E" series engine.

The R-2800 first flew in 1940, but the "B" series is what started them down the right path. That said, actual development times for the Grumman Cats wasn't bad at all.

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## tomo pauk (Jan 24, 2017)

Yay, KJ Lesnick is here 



GregP said:


> You are asking questions that I doubt younger people can answer. There are a few in here who stubbornly think the U.S.A. should have bought foreign weapons, particularly the DH Mosquito.
> 
> But the attitudes of the time would preclude that from ever happening at the time when it might have been really useful. That being said, even if we could post the real-world reasons for the items above, very few people today would acceot the reasoning behind them. Everyone wants to take apart the decisions and replace them with whatever decision seems best using the infallible power of hind-sight and knowledge of everything we know today after years of digging and changes in attiudes.
> ....
> The valves in an Allison were sodium-filled Stellite, and that required tungsten and molybdenum. The supplies weren't unlimited and ALL military piston engines needed valves, so they got first priority for the alloys. Turbine wheels came further down the food chain. Other makers also needed wear-resistant valves, and Allison was forced to share that with Rolls-Royce and, eventually, commerical competitors. That was NOT a welcome decision by Allison or GM, but helped the war effort overall.



Oh boy. Talk about mis-informations and off-topic drumming.



> I don't know why the engine makers didn't experiment more with 2-stage superchargers, but it most likely is due to their primary customers wanting turbochargers instead. Everyone was sort of waiting for the "breakthough" in turbocharging and it never did get to a stage of development that was as reliable as 2-stage superchargers. I think charge coolers were a big issue: inter / after coolers that could drop the etemperature of the compressed air and/or air/fuel mixture and delay detonation.



Bristol, Junkers and P&W experimented with 2-stage superchargers before the war of 1939. 



> If you go look up the history of the R-2800, you will find a LOT of master-rod designs, a lot of failures before "getting it right," a lot of cooling fin designs, and a lot of hard work. Early R-2800s weren't necessarily great engines. The White book, "R-2800 Pratt and Whitney's Dependable Masterpiece" is a great source. The timeline doesn't exactly allow for early use in large numbers. "B series engines were built from 1943 and "C" series were from 1945. An "A" series engine has very few parts in common with an "E" series engine.
> The R-2800 first flew in 1940, but the "B" series is what started them down the right path. That said, actual development times for the Grumman Cats wasn't bad at all.



January of 1942 saw 220 copies of R-2800 'B' engines produced by P&W, and 65 by Ford. In 1942, more than 11000 (eleven thousand) of R-2800 B series of engines produced.
The R-2800 C series were produced in numbers from mid-1944, with 3100+ delivered in 1944.

In 1941, more than 1700 R-2800 were produced.


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## wuzak (Jan 24, 2017)

GregP said:


> You are asking questions that I doubt younger people can answer. There are a few in here who stubbornly think the U.S.A. should have bought foreign weapons, particularly the DH Mosquito.



That has nothing to do with the topic at hand.

Not to mention the initial moves in procuring the XP-65/F7F predated the first flight of the Mosquito.

Or the fact that they were designed around a completely different requirement.




GregP said:


> The valves in an Allison were sodium-filled Stellite, and that required tungsten and molybdenum. The supplies weren't unlimited and ALL military piston engines needed valves, so they got first priority for the alloys. Turbine wheels came further down the food chain. Other makers also needed wear-resistant valves, and Allison was forced to share that with Rolls-Royce and, eventually, commerical competitors. That was NOT a welcome decision by Allison or GM, but helped the war effort overall.



Oh no, even more technology Allison was forced to share with that dastardly British Rolls-Royce company. Oh, how badly were Allison screwed?

Except that Allison invented neither stellite steel or sodium filled valves. The former was invented by a steel company (go figure) and the latter by the USAAC Engineering Division (who would also develop the "hyper" cylinder) under Sam Heron - an Englishman.

So Allison would have had to buy licences to make their own, as would Rolls-Royce.

Assuming Rolls-Royce used stellite and hadn't developed their own high temperature wear resistant steel.

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## tomo pauk (Jan 24, 2017)

Zipper730 said:


> ...
> From what I remember
> 
> The USN issued a requirement for an interceptor program: This produced the XF5F, XFL-1, and F4U, of which the latter one.
> ...


Item 2 is wrong re. USAAF wanting a long-range escort fighter with XP-65 - doctrine for long range escort did not existed in 1941 in the USA.





> What I'm curious about is the following
> 
> Why didn't they just use R-2800's with either 1 stage supercharging (F7F), or two-stage supercharging, or a turbocharger?
> Why did the USAAF want 37mm cannon: They were brutal when they hit, but fired slowly, had bad ballistics, and permited only 40-45 rounds; the 20mm hit greatly harder than the 50 calibur, had similar refire rate, ballistics were a little inferior but acceptable at 400-yards for most purposes
> Why did the USN just put 4 x 20mm in the nose and disregard the 0.50? That was more than enough...



The US 20mm was not a done deal by 1941, while the 37mm was, and it had a role for the primary purpose of USAAC fighters of 1941 - killing the enemy bombers close and above the USA and it's territories.
Re. USN request - having just 4 x 20 mm on two big, powerful, heavy and expensive R-2800 probably lookes as a vaste, only one R-2800 was more than capable to haul those 4 cannons. USN was never sold on the 37mm M4 cannon.


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## GregP (Jan 24, 2017)

It is right on topic guys. He was asking why some things happened the way they did and what I wrote is exactly on-topic. I'm amused that Tomo is ttelling me it's mis-information. That's funny. It's like me telling him why things happened the way they did in Poland. Thanks for a good one, Tomo.

And I didn't say nobody experimented with 2-stage superchargers, I said I didn't known why they didn't pursue it MORE, and still don't. I was taking about U.S. manufacturers, not British manufacturers. And nobody in here can tell me unless they were there. Perhaps the ones that were developed were pretty good for the radials, but I've never been happy with the auxiliary supercharger that Allison used. It worked, but the unit on the Merlin is much better designed. There was considerable room for improvement.

Allison's main beef was sharing bearings and we've had threads on it before. Valves that wear longer were important, and made their way around to everyone. It was inevitable, and even Allison knew it. I'm glad they did, and I bet everyone else is glad they lasted longer than WWI valves, too. I still don't see anyone posting the amount of metals that were avilable and when. It's is possible they could have made more of anything, but the supply of tungsten and molybdenum were limiting factors and the bombers were allocated the major supply of turbos in the U.S.A. You surely weren't going to make them from mild steel or magnesium!

I'm not too sure the very early R-2800s were all that reliable or long-lasting. Not too many are still flying around as with later series engines. We fly at least 3 on a regular basis and a few more occasionally and none are "A" series engines. I can say the same for most of the R-2800s that come around, and that's more than just a smattering. Most people who get one rebuilt want late master rods. It's sort of like getting an Allison rebuilt as an early dash number ... they still want 100-series internals, including the 12-counterweight crankshaft.

The actualy development timelines weren't bad at all, looking at when things were ordered and the priority places on them. We essentially declared was at the start of 1942, and many new things were coming into service not all that much later. I'm not sure it was possible to make things happen any faster and the planes we had on hind were required to carry the fight until new ones were ready. The only real way to speed it up would have been to order the new planes before we were in the war. Then development COULD have been moved back in time enough to matter. I'm doubting this one was realistically ever going to happen because of the ecomomic situation at the time in the late 1930s.

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## fastmongrel (Jan 24, 2017)

GregP said:


> Other makers also needed wear-resistant valves, and Allison was forced to share that with Rolls-Royce and, eventually, commerical competitors. That was NOT a welcome decision by Allison or GM, but helped the war effort overall.



Rolls Royce were using valves that were sodium cooled and with Cobalt alloy friction surfaces on the R racing engines in 1931. Stellite was old news by the 1920s and Dr Heron was experimenting with Sodium cooled valves at the Royal Aircraft Establishment in 1917.

Any engine company that didnt know about the above by 1939 was staffed by morons.

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## Zipper730 (Jan 24, 2017)

wuzak said:


> The USAAC/F did have a fascination with the 37mm cannon. Probably because of its destructive power.


True, but shooting is only one part of the equation... anybody can shoot a gun, not everybody can make it hit something.



tomo pauk said:


> The US 20mm was not a done deal by 1941, while the 37mm was, and it had a role for the primary purpose of USAAC fighters of 1941 - killing the enemy bombers close and above the USA and it's territories.


I guess there was the P-67 too...


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## GregP (Jan 24, 2017)

Stellite was invented by Elwood Haynes up in Canaada in Deloro in 1909. He became a millionaire in 1912 and moved back to Indiana and took the Haynes Stellite Company with him, just up the road from Allison Engineering. The other Stellite company with Haynes original partner, Michael O-Brien was eventuallly sold and still exists in Germany today as the Kennametal Stellite Company. Haynes' museum is still in Indiana, with some of his original inventions and developments. Haynes was primarily using it for cutting teeth in saws and cutlery, but the wear resistance wasn't tried in poppet valves until the move back to Indiana. Coincidentally, Elwood Haynes also had an automotive interest and worked in Indiana to help devlelop them. Allison Engineering was among his first customers for them, and helped develop these. They propagated, but Allison was never happy about sharing developments. Later they were forced to share also bearing patents, which was their primary source of WW2 displeasure. But all along, developments they made were shared by others. Allison didn't develop these alone, they partnered with Haynes. Allison kept theirs in-house and Haynes shared with the industry, as had always been his intent. Allison didn't develop in partnership after that ever agian while James Allison was alive.

You can make out of that whatever you want.

The questions above were mostly concerned with why things developed the way they did. In point of fact, I tried to address why the Navy wanted 37 mm cannons, why they went to four 20s, and why 2-stage superchargers weren't better-developed in the USA, which was and IS because the main U.S. engine customers in the U.S. miltary were favoring turbochargers. I also said I didn't see how it was possible to field the R-2800 any earlier, and still don't. It basically got into service when it could get there.

Had the U.S.A. or even US companies been able to cooperate with Rolls-Royce on a standard 2-stage supercharger for the Allies, we might have had some better aviation engines sooner. I'm not sure either side would have been willing to do that without the war being on. It' s like one of those what-ifs about whether or not the Germans could have really gotten jets into the fray sooner.

There some unlikely circumstances which might have allowed it, but not realistically. We got stuck with the superchargers we had in the real world, and that's as good as they got. So we went with what we had when we had it.

Guys, nobody writes things exactly like someone else does, and this has gotten to the point of not being fun anymore.

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## wuzak (Jan 24, 2017)

Greg, I have requested some documents form the UK National Archives, the title of which is:

Secrecy agreements re. manufacture of Allison bearings at aero factory, between Austin Co. & various employees

Which certainly sounds like they were made under licence agreement.

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## wuzak (Jan 24, 2017)

Unfortunately those documents are not available at the Nation Archive, but rather the British Motor Industry Heritage Trust. So I can't get copies of the files.


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## wuzak (Jan 24, 2017)

Zipper730 said:


> wuzak
> 
> I didn't realize the R-2800 and R-3350 were concurrent designs. I thought (for some reason) that the R-2800 and R-2600 were concurrent.



The R-2800 was slightly behind the R-2600 in timeline. The R-3350 was slightly behind the R-2800.


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## wuzak (Jan 24, 2017)

Zipper730 said:


> The RAF early on had 8 x 0.303's in the Spitfire and Hurricane, followed by 12 x 0.303's for the Hurricane and Typhoon, followed by 4 x 20mm for the Hurricane, Typhoon, and Tempest.



And? So? Therefore?


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## Zipper730 (Jan 24, 2017)

Wuzak,

The point I'm getting at was that 4 x 20mm was fine


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## Shortround6 (Jan 24, 2017)

A few observations for now.

1. On the subject of guns. The US Army was enamored of the 37mm gun for a number of reason, part of it was because it was home grown, although they certainly did at least test several other options including Danish Madison cannon. The actual truth is that a _LOT _of the pre-war cannon promised a lot more than they delivered in regards to reliability. Also most of the cannon on offer had rather low rates of fire in the mid to late 30s. It was only in the very late 30s that the Hispano got to 600rpm. So.... a 37mm at 140rpm or a 20mm at 400-450rpm? 
Another reason was the size of anticipated targets. The USAAC having built the XB-15 and XB-19 and with America's isolationist policies one theory was that any air attacks would be from similarly sized aircraft. There were several design studies between the XB-19 and the B-29 and as another indicator here is a drawing of the unbuilt Martin XB-16;





six Allison engines. And don't forget, the Army started initial design talks that would lead to the B-36 in the Spring of 1941. against such aircraft bigger than 20mm guns have an obvious attraction. 
As a further note on the Army and Navy on guns, they did not always play well together. During the 1930s when the need for light automatic cannon for AA use was becoming glaring apparent the Army proceed with their own 37mm AA gun while the Navy designed and built the infamous 1.1 in (28mm) machine cannon. However the Navy changed direction sometime after summer of 1940 when they got their hands on a twin mount 40mm Bofors and started plans for production even before getting a licence, I don't know when the Army joined in but by 1943/44 the 40mm Bofors was in widespread Army use and the Army 37 AA gun was on the way out. 

Please remember that if you are buying weapons to respond to what your enemy is actually using in combat you are 2-4 years too late. The designers and procurement people are trying to anticipate needs 2-5 years into the future. 

The engine question R-2600 vs R-2800 vs R-3350 gets really convoluted but lets try to sort through things.
1. None of these engines were worth much at high altitude *without* an auxilary or two stage supercharger. Even with a two speed supercharger FTH was around 12-14,000ft and engine power was several hundred HP below take-off power. A Series R-2800 had 1850hp for take off but only 1500hp at 14,000ft. The R-2600 was proportionally worse. If you want a low altitude plane you are all set, if you want to escort turbocharged bombers then single stage supercharged radials won't work. 
2. The Wright engines have a bit of a twisted path. The R-2600A did predate the R-2800A and at some point they did design and build a handful of R-3350 engines. However to get to 1700hp Takeoff with the R-2600 required a total redesign including changing the crankcase from aluminium to steel. This R-2600B slots in between the R-2800A and B in timing. The R-3350 was placed on hold while the R-2600 was sorted out (and while Wright went down the R-2160 Tornado rathole) and was taken back out, dusted off and redone using a lot of the knowledge gained in working on the R-2600B. 
Perhaps a list of dates on when the *5th *engine was accepted will help put things in perspective.
R-2600A............March 1938
R-3350BA..........Oct 1939
R-2800A............March 1940 
R-2600BA.........June 1941 
R-2800B............Oct 1941
R-3350BB..........Aug 1942
Please note that for the R-3350BA it took from 1938 to the end of 1942 to build 77 engines. Lack of demand or lots of teething troubles? 

Sodium cooled exhaust valves were pretty much a world wide industry standard by 1941. at least according to Wilkinson's "aircraft Engines of the World" granted it may have mistakes but about the ONLY high powered aircraft engines NOT using sodium filled exhaust valves are the Bristol sleeve valve engines. Even such US powerhouses as the Continental R-670 and Lycoming R-680 used sodium cooled exhaust valves and some sources say they were used on the Ranger inline 6 and V-12.

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## Shortround6 (Jan 25, 2017)

Zipper730 said:


> What I'm curious about is the following
> 
> Why didn't they just use R-2800's with either 1 stage supercharging (F7F), or two-stage supercharging, or a turbocharger?
> Why did the USAAF want 37mm cannon: They were brutal when they hit, but fired slowly, had bad ballistics, and permited only 40-45 rounds; the 20mm hit greatly harder than the 50 calibur, had similar refire rate, ballistics were a little inferior but acceptable at 400-yards for most purposes
> Why did the USN just put 4 x 20mm in the nose and disregard the 0.50? That was more than enough...


I think we have answered most of the questions. I would add in regards to the engine question that it was not so simple to _ADD _two stage supercharging to an existing fighter design. One text book claimed about 10 cubic feet of volume was needed for a _1000hp _engine for the supercharger AND intercooler AND ducts. Since horsepower is pretty much a function of airflow a 2000hp engine is going to need nearly double the volume, there is some savings in scaling up but no, you are not going to cram 2000hp worth of airflow into 12-14 cubic feet. On bombers with large wings and engine nacelles there was a lot of room to put things. On fighters you pretty much designed for one type of engine from the start. Please note that the Spitfire and P-51 and Mosquito all used substantially larger radiator sections to fit in the intercooler radiators than the single stage engined planes. 

Finding information on the thinking of the Navy on the armament is hard. However sticking four 20mm cannon in the nose requires a bit of thought. The F7F as designed carried the 20mm guns and ammo pretty close to the center of gravity. 800 rounds of 20mm ammo weighs around 560lbs so you have to be careful where you put it or the flying characteristics of the plane change as the ammo is used.
You also have the ongoing saga of the high rate of fire .50 cal gun. The Belgians (The FN company) claimed a rate of fire for their 13.2 mm version in 1938/39 of close to 1200rpm. The US Army and Navy were getting 600rpm at the time and that with short belts. the .50 was boosted to about 800rpm fairly easily but then followed a succession of contracts/projects by several different companies to boost the rate of fire to 1200rpm or above. Some companies had several different projects all with the pretty much the same goal. After 15-20 projects and a number of broken and blown up guns and 2 1/2 to 3 years they finally got the M3 machinegun. 
Now in the planning for future fighters to fly 2-3 years down the road _which _.50 cal machine gun were they planning on using? they one they already had or the one they were hoping to have after pouring all that time and money into it? Four of the fast firing guns almost equal the rate of fire of 6 of the standard 800rpm guns so a fighter with four 20mm guns and four .50s had a very formidable armament. 
Also please note that on the F7F the 50.cal guns were located pretty much under the pilot and the nose gun ports required long blast tubes to reach the actual guns. Again they had to keep the ammo close to the center of gravity.

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## Shortround6 (Jan 25, 2017)

As far as Stellite goes, James Allison died in Aug of 1928. What the Allison company did or did not do with stellite's development before then seems to have little bearing on it's use in the 30s and 40s. 

A pair of books that shed considerable light on the state of the art of aircraft engine construction of the beginning of WW II are "Aircraft Engines" By A.W.Judge. Volumes I and II. first published in 1941. there are later editions. 
The 1941 edition has a 14 page section just on valves and valve gear. And for all of us arm chair engineers (who think we know better than real engineers) it is full of details like alloy mixes, Brinell hardness, yield strengths and so on. 
Stellite was used for a facing on the valves and valve seats although sometimes an alloy called "Brightray" was used. Stellite buttons were sometimes welded on to valve stems to increase wear resistance. There were quite a number of alloys used for valve seats but many were faced with Stellite or Brightray (or perhaps other propitiatory alloys). Some alloys were developed to mimic the expansion rate of aluminium alloy cylinder heads so there was less chance of the insert dropping out at high temperature.

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## fastmongrel (Jan 25, 2017)

Rolls Royce developed quite a few Ferrous and Non Ferrous alloys for their own use and worked closely with companies like Firth Brown steel, High Duty Alloys Ltd, Henry Wiggin and Co (Brightray for exhaust valves similar to Stellite) and Reynolds Tubes Ltd. 

I imagine the US aero engine builders did the same working closely with specialist companies. Allison were fortunate to be part of the giant GM corporation who had laboratories working on alloys for cars.


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## Zipper730 (Jan 26, 2017)

Shortround6 said:


> A few observations for now.
> 
> 1. On the subject of guns. The US Army was enamored of the 37mm gun for a number of reason, part of it was because it was home grown, although they certainly did at least test several other options including Danish Madison cannon.


The Madsen was a 23mm cannon, if I recall correctly


> The actual truth is that a _LOT _of the pre-war cannon promised a lot more than they delivered in regards to reliability. Also most of the cannon on offer had rather low rates of fire in the mid to late 30s. It was only in the very late 30s that the Hispano got to 600rpm. So.... a 37mm at 140rpm or a 20mm at 400-450rpm?


I see your point


> Another reason was the size of anticipated targets. The USAAC having built the XB-15 and XB-19 and with America's isolationist policies one theory was that any air attacks would be from similarly sized aircraft.


By 1937 or 1938 weren't we aware what the Germans were doing at all?


> As a further note on the Army and Navy on guns, they did not always play well together. During the 1930s when the need for light automatic cannon for AA use was becoming glaring apparent the Army proceed with their own 37mm AA gun while the Navy designed and built the infamous 1.1 in (28mm) machine cannon.


Infamous?


> However the Navy changed direction sometime after summer of 1940 when they got their hands on a twin mount 40mm Bofors and started plans for production even before getting a licence, I don't know when the Army joined in but by 1943/44 the 40mm Bofors was in widespread Army use and the Army 37 AA gun was on the way out.


40mm would have been better as I think it had a higher muzzle velocity...


> The engine question R-2600 vs R-2800 vs R-3350 gets really convoluted but lets try to sort through things.
> 1. None of these engines were worth much at high altitude *without* an auxilary or two stage supercharger. Even with a two speed supercharger FTH was around 12-14,000ft and engine power was several hundred HP below take-off power.


Wait, I can't speak for the R-2600 but the R-2800 could do around 23,800...


> If you want a low altitude plane you are all set, if you want to escort turbocharged bombers then single stage supercharged radials won't work.


Okay


> Please note that for the R-3350BA it took from 1938 to the end of 1942 to build 77 engines. Lack of demand or lots of teething troubles?


That was teething trouble...


> I would add in regards to the engine question that it was not so simple to _ADD _two stage supercharging to an existing fighter design. One text book claimed about 10 cubic feet of volume was needed for a _1000hp _engine for the supercharger AND intercooler AND ducts.


You would want that there from the start


> Finding information on the thinking of the Navy on the armament is hard. However sticking four 20mm cannon in the nose requires a bit of thought. The F7F as designed carried the 20mm guns and ammo pretty close to the center of gravity. 800 rounds of 20mm ammo weighs around 560lbs so you have to be careful where you put it or the flying characteristics of the plane change as the ammo is used.


I think I understand, you could make an airplane with a wildly varying CG...


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## Shortround6 (Jan 27, 2017)

Zipper730 said:


> By 1937 or 1938 weren't we aware what the Germans were doing at all?


There was a lot of secrecy before WWII, for example the Germans did display a DB 600 engine at the 1938 Paris airshow. even though it was months after the fuel injected DB 601 set a number of records. The Fuel injection was _NOT _put on display and even photographs were not published in common magazines. A number of German aircraft were not publicized much, if at all, until they had been in production for a while. 


> Infamous?


Yep, over complicated and requiring more than it's fair share of maintenance. 
1.1"/75 caliber gun - Wikipedia



> 40mm would have been better as I think it had a higher muzzle velocity...








Army 37mm AA gun. MV 2600fps with 1lb 5oz projectile. 

40mm Bofors gun MV 2870fps with 2lb projectile. The Bofors was better, both fired at about 120rpm. 



> Wait, I can't speak for the R-2600 but the R-2800 could do around 23,800...


Not with a single stage supercharger. Navy engines with 2 stage superchargers could make 1650hp at 22,500ft no ram and no water injection but were B series engines.


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## Zipper730 (Jan 27, 2017)

Shortround6 said:


> There was a lot of secrecy before WWII, for example the Germans did display a DB 600 engine at the 1938 Paris airshow. even though it was months after the fuel injected DB 601 set a number of records. The Fuel injection was _NOT _put on display and even photographs were not published in common magazines. A number of German aircraft were not publicized much, if at all, until they had been in production for a while.


I thought the Ju-87, Ju-88, and He-111 were common knowledge in basic shape


> Army 37mm AA gun. MV 2600fps with 1lb 5oz projectile.
> 
> 40mm Bofors gun MV 2870fps with 2lb projectile. The Bofors was better, both fired at about 120rpm.


The 40mm sounds like a better choice if you're going to push for a heavier gun (at this point in time, had we procured any Bofors equipment? I ask because they're Swedish...)


> Navy engines with 2 stage superchargers could make 1650hp at 22,500ft no ram and no water injection but were B series engines.


I don't know how the B's differed from earlier set-ups.


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## wuzak (Jan 28, 2017)

Zipper730 said:


> To be clear though: The P-40 used the 0.50 calibur ammo it did because the P-36 did and it was a P-36 with inline, and the P-47 was based on limited wartime experience, correct?



0.30" and 0.50" on early models being replaced by all 0.50"s on later models - because they were the standard guns the USAAC/F used.


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## Shortround6 (Jan 28, 2017)

Zipper730 said:


> I thought the Ju-87, Ju-88, and He-111 were common knowledge in basic shape


That is true but how much did the US know about the Do 19 or Ju 89? Or what was supposed to replace them? 
The USAAC was worried about planes that could reach the US, not planes that had trouble flying past one European country. The Russians had flown 6 and eight engine aircraft in the early/mid 30s and the French had flown 6 engine monoplane flying boats in the Mid 30s. Very large planes were possible even if very expensive. The USAAC was trying to plan ahead. 



> 40mm seems a better choice if you're going to go huge.


 it was but then the 40mm bofors didn't exist when work started on the 37mm AA gun. Some countries tended to "stick" with certain sizes of cannon barrels because some of the barrel making machinery and ammo making machinery carries over. The US 37mm AA gun used the same size ammo as the 37mm AT gun even if some of the projectiles weren't exactly interchangeable. Please note the 37mm aircraft gun used different ammo. 



> To be clear though: The P-40 used the 0.50 calibur ammo it did because the P-36 did and it was a P-36 with inline, and the P-47 was based on limited wartime experience, correct?


The .30 cal ammo was the standard rifle ammo and the .50cal was a *standard caliber and gun *for the Army and navy. It was quite possible to convert a water cooled AA .50 gun to an aircraft machine gun with the proper barrel, barrel jacket and buffer assembly. The US had been putting .50 cal guns in fighter planes since the 1920s. Or had least had the option. One of the cowl guns cold always have been a .50 even if not always installed. Standerdizing ont eh .50 allowed for a considerable savings in logistics over using different guns for different purposes even if the .50 was not ideal in some situations. 



> I don't know how the B's differed from earlier set-ups.



P & W engines were described by a letter designation as to the model of the power section ( crankcase, crankshaft, cylinders, etc) Reduction gears and superchargers could vary on the same series engines. B series engines included single speed superchargers used in conjunction with turbos in P-47s, two speed single stage supercharges used in B-26 bombers and others, and single speed speed superchargers with the "two" speed auxiliary supercharger used in the F4U, F6F and P-61. The A series were only massed produced with the 2 speed supercharger. Experimental "A" series engines used other supercharger set ups but none saw service use. The later "C" series engines (NO common parts with the "B") also had multiple supercharger set ups, pretty much the same ones as teh "B" although details changed.

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## XBe02Drvr (Jan 28, 2017)

Zipper730 said:


> I think I understand, you could make an airplane with a wildly varying CG...


"Couldn't keep the pipper on target! Soon as I touched the trigger, pipper rose sharply off target." At GE, we got complaints like this as soon as the first cannon equipped F-4Es were tested. The cannon (and ammo drum) were WAY out in front of everything except the radar dish, and at 100 rds/sec, the CG was shifting faster than the pilot could compensate. (Didn't have today's fly-by-wire active-stability computers then!)
Solution: redesign the feed mechanism and drum to capture the spent brass and feed it back into the vacated portion of the drum. ("Elbows and a__holes" on the production floor trying to incorporate the design changes without slowing production.) Unfortunately this changed some parameter having to do with vibration modes or resonant frequencies or something like that, such that once the cannon was fired, the radar was OTS UFN.

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## Niceoldguy58 (Jan 29, 2017)

Shortround6, unfortunately that drawing is NOT of the Martin XB-16, but rather of the Materiel Division Model 319. The attribution of many designs in the 1934-1938 range are woefully inaccurate. This and more will be finally cleared up in 2018.

The AAC had a nearly obscene love for the 37mm gun, planning to fit it to nearly everything from fighters to bomber gun turrets. I even have official drawings of a wing redesign on the P-51/A-36 to fit an internally-mounted 37mm. Pretty much every Attack aircraft from at least the A-26 on through the A-41 had multiple 37mm's fitted in at least the design process if not the prototypes.

I've been attempting to put together the story of the 37mm for a long time. Despite anything said about hitting power, etc., my gut feeling is that there is an unstated "not invented here" underlying attitude by the Army/Army Air Corps that negatively impacted the 20mm. The 20mm WAS discussed, up to and including being fitted to the P-40 (separate consideration from the Madsen 23mm externally mounted). In WWII, only the Navy fitted 20mm to its aircraft, with the USAF lagging until the 1950s.

As for the weapons mounting in the F7F/XP-65, I surmise that the streamlining of the nose of the aircraft made it impossible to mount weapons around the nose wheel. The wings were certainly large and deep enough to mount numerous .50cals or a smaller number of 20mms. I don't know too much about the XP-65, but that is one where I don't know of any interest in mounting 37mms. Then again, the AAC wasn't involved in the XP-65 long enough to look at that mounting seriously.

Regarding engines, I recommend people obtain the Kilner Board Reports which resulted in the R-40A and R-40B programs. One of the key items in those reports was concern that the AAC was relying too much on one engine type in its Specifications and the designs submitted, specifically the Allison inline. This resulted in two different directions of design, one being the universally unsuccessful "X" engines and the other greatly expanded development of radial engines mentioned earlier in this thread. Fortunately, Pratt and Whitney had plunged into radial technology with both feet, resulting in the R-2800 and eventually the R-4360. Wright had also done so with the R-2600 and the trouble-prone R-3350.

The Navy, of course, had turned to radial engines exclusively earlier in the 1930s, which frankly makes many of the entries for the eventual F7F project a bit peculiar. I recommend your looking at the section on this program found in _American Secret Projects _by Tony Buttler and Alan Griffith (me) which goes into some length about all the entries and includes 3-views.

I hope this is useful.

AlanG

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## tomo pauk (Jan 29, 2017)

Hello, Alan,



Niceoldguy58 said:


> The 20mm WAS discussed, up to and including being fitted to the P-40 (separate consideration from the Madsen 23mm externally mounted). In WWII, only the Navy fitted 20mm to its aircraft, with the USAF lagging until the 1950s.



The USAF was installing the 20mm on P-38, P-51 (four per aircraft), P-400 (version of P-39), P-61 and A-20 (four in the nose).


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## Shortround6 (Jan 29, 2017)

First, hank you for the correction on eh XB-16. But is does show the USAAC was interested in very large aircraft at the time. Wither for offence or for planning for defense against. 

Chinn's "The Machine gun" volume 3 pages 31-39 and pages 351-380 had a history and technical details of the US 37mm automatic cannon, but few, if any, mentions of policy or thinking behind requirements, or much for test results except for broken parts or malfunctions (on the 37mm those mentions are few or non-existent).
Quite a bit of work was done on developing disintegrating link belt feeds and feeding from left or right of the gun/s as opposed to the AIrcobra style feed. 
There were three basic guns with a host of modifications/prototypes. Basically the M4 as used in the Aircobra. The M9 which was an aircraft version of the M1A1 37mm AA gun (using the same ammo as the AA gun) and the M10 which was basically a fast firing M4 (up to 165 rpm but using the same ammo as the M4). How many of the M9 and M10 were actually installed in service aircraft might be in dispute as apparently development took longer than expected and the M4 had to be used in some cases. 

The Hyper engine/s started in 1932 with Continental working essentially as the Army's machineshop. Lycoming joined in around 1935/36 (with a few ex Continental engineers), P & W started the X-1800 in 1938 (?) In 1938 Allison built a total of 14 engines.


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## Niceoldguy58 (Jan 29, 2017)

Tomo, you are quite correct about the fighters/attack ac sporting the 20mm. I had totally forgotten about them and was writing in a hurry. My apologies.

Shortround6, I will bow to your recitation of the dates for commencement on the Hyper-engines. I took some time to actually look back into my notes instead of relying on an aging memory filled with DH-4 info today and looked at the number of single and multi-engine designs that were originally intended for one of these engines. There were quite a few.

Many thanks for the corrections.

AlanG


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## Shortround6 (Jan 29, 2017)

You are bringing much information to the table also. Much appreciated. 

Now in fairness I would note that while Continental and Lycoming _started _in those year progress was near glacial in speed and for a number of years the only hardware was one and two cylinder test rigs. Complete 12 cylinder engines only being assembled in 1939 or 1940 so the Allison did sort of become the defacto liquid cooled engine for a number of projects. Or filled in for prototypes while the "wonder" engines were still being worked on in the shops. 
As you are well aware, what was planned or hoped for often fell well short of being accomplished in a timely fashion which makes trying to sort out intentions or policy a bit difficult.


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## Zipper730 (Dec 16, 2017)

wuzak said:


> Regarding the engines, the project timing probably didn't allow consideration of the R-2800.
> 
> According to this, the project started in 1939. At which point the R-2800 was still relatively early in development, while the R-2600 was in production.
> 
> The XF6F also used an R-2600.


Had the USN or USAAF procured an aircraft with a new engine before this time? Regardless, as the F6F evolved, the R-2600 was replaced with the R-2800...



GregP said:


> It is right on topic guys. He was asking why some things happened the way they did and what I wrote is exactly on-topic. I'm amused that Tomo is ttelling me it's mis-information. That's funny. It's like me telling him why things happened the way they did in Poland. Thanks for a good one, Tomo.
> 
> And I didn't say nobody experimented with 2-stage superchargers, I said I didn't known why they didn't pursue it MORE, and still don't. I was taking about U.S. manufacturers, not British manufacturers. And nobody in here can tell me unless they were there. Perhaps the ones that were developed were pretty good for the radials, but I've never been happy with the auxiliary supercharger that Allison used. It worked, but the unit on the Merlin is much better designed. There was considerable room for improvement.
> 
> Allison's main beef was sharing bearings and we've had threads on it before. Valves that wear longer were important, and made their way around to everyone. It was inevitable, and even Allison knew it.


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## wuzak (Dec 16, 2017)

Zipper730 said:


> I'm not sure I understood the rationale behind the Hyper-engine development. I get that they wanted a horsepower for every cubic inch of displacement, but I'm curious why they developed so many engine proposals when they had so little money to fund them (particularly after the early 1930's when there was little demand for inline engines outside of airships and military designs).



You are missing another part of the equation - the aim was also to get 1hp per pound of weight.

As for funding, the hyper program was funded by the USAAC Materiel Division. The basic cylinder was developed by Sam Heron at Wright Field, Ohio.

Who did you think funded them?

As to why there were so many developments (well, there were the Continental and Lycoming engines, and the Chrysler one came later) is probably because those developments were substantially or wholly funded by the US Army.

This funding model may have delayed progress. Because each new development had to be approved by the Army, thus there was a lot of bureaucracy.

The Continental hyper engine program started before the Rolls-Royce PV-12, yet Continental were still doing single engine development when the Merlin went into service with the RAF in the Hurricane.

Also, there was no purpose to their design beyond military use.


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## MiTasol (Dec 16, 2017)

Niceoldguy58 said:


> In WWII, only the Navy fitted 20mm to its aircraft, with the USAF lagging until the 1950s.
> AlanG



P-38 all models and P-39D-1 had 20mm cannon


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## tomo pauk (Dec 16, 2017)

So did the P-61s and P-51s/Mustang II. Plus a batch of A-20s that Soviets received.


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## pbehn (Dec 16, 2017)

20mm cannon were the RAFs preferred armament on fighters from around 1939/40, Hurricane Typhoon Tempest Whirlwind and Spitfire all had cannon, various reasons why they weren't universal but it was a policy.


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## Zipper730 (Dec 17, 2017)

wuzak said:


> You are missing another part of the equation - the aim was also to get 1hp per pound of weight.


That makes more sense actually...


> As for funding, the hyper program was funded by the USAAC Materiel Division. The basic cylinder was developed by Sam Heron at Wright Field, Ohio.
> 
> Who did you think funded them?


Well you said USAAC Material Division...

As for the cylinder-design: Why not just use an off the shelf cylinder while the new one is being developed? It might require restrictions on the engine, but at least the rest of the machinery can be run and ironed out.


> As to why there were so many developments (well, there were the Continental and Lycoming engines, and the Chrysler one came later) is probably because those developments were substantially or wholly funded by the US Army.


I understand that they funded them, but if you have budgetary problems -- you either have to throttle back all designs you have (and if you have a lot, all go to a crawl), throttle back some selectively (and risk getting accused of impropriety), or cut some designs and allocate funding to the best.


> This funding model may have delayed progress. Because each new development had to be approved by the Army, thus there was a lot of bureaucracy.


So it had to go up a lot of layers to make approval or rejection; then go back down all those layers?

Also, was this a 1-way system (Army tells them what to do, the company does it), or 2-way (Army tells them what to do, Company does it; Company submits ideas of their own/Army listens and tells them yes/no).


> The Continental hyper engine program started before the Rolls-Royce PV-12, yet Continental were still doing single engine development when the Merlin went into service with the RAF in the Hurricane.


I'm still surprised it took them so long to realize other engine developments at the time (NACA cowling for starters, improved radiator designs) meant the flat cylinder was unneded.


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## XBe02Drvr (Dec 17, 2017)

Zipper730 said:


> As for the cylinder-design: Why not just use an off the shelf cylinder while the new one is being developed? It might require restrictions on the engine, but at least the rest of the machinery can be run and ironed out.


Zipper, some of the things you say stretch the limits of credulity, but this one hits the absurdity button so hard clenched jaws can't keep my mouth shut!
Clearly you've never gotten your hands dirty with any of this stuff. An engine is an integrated system that has to fit and work together, and the cylinder is where it's happening. You can't design a crankcase, crankshaft, con rods, gearbox, accessory case, carburetion system, etc, around a cylinder that doesn't exist yet in any definite form. Sure, you can design around what you imagine it will be, but the development process has a funny way of throwing a monkey wrench into that. Then you have to redesign everything. If you "temporarily" bolt a set of "off the shelf" cylinders (provided you even have suitable substitutes) into this dream engine of yours, you're still going to have to re-engineer everything once you know the final configuration and dynamics of the developed cylinder design. Think you can sell that concept to Material Command in an era of shrinking budgets and isolationist thinking? Good luck!
Cheers,
Wes

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## Shortround6 (Dec 17, 2017)

Zipper730 said:


> I'm still surprised it took them so long to realize other engine developments at the time (NACA cowling for starters, improved radiator designs) meant the flat cylinder was unneded.



It took more than that. And do try looking up the NACA cowling, it was an ever evolving item all on it's own. It did NOT spring into being in a single month or even year fully done and in final form. The early ones had no internal baffling, Like between the cylinders of the engine, no adjustable slots or flaps on the exit (no adjustment of airflow for speed or power output/actual cooling need) And so on.

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## pbehn (Dec 17, 2017)

What I find interesting reading about engine development is how nothing was or is as simple as it seems. The Vulture should have been a simple development as it used much of the Peregrine design, however it wasn't successful because, well because things are never that simple. Then, as a company gets everything sorted, there is a need for something better. Just when RR got the Merlin to produce 2000 BHP someone said "Hey that's great but can you cut down the frontal area?

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## XBe02Drvr (Dec 17, 2017)

pbehn said:


> What I find interesting reading about engine development is how nothing was or is as simple as it seems.


Reminds me of the crusty old Chief Avionics Technician who woke us up on the first morning of antennas and transmission lines phase in A School.
"Any you maggots got any clue to what the letters F M stand for?"
(Class hotshot): "Sure, Chief that's Frequency Modulation, where the carrier wave is modu--"
"Wrong, Sailor! You believe that bullpucky? What, you some kinda engineer or somethin? Any right thinkin' tweet knows it stands for f--kin' magic! You think those test rigs them engineers design with all their fancy formulas actually WORK when they build 'em? 'Course not! They tweak this and try that, and finally go back to their drawin' boards in  and tell the techs to tear down and dispose of the rig. Well no tech worth his salt tears down a perfectly good rig without first applying a little "FM" just to see what might happen. Sooner or later, word filters up to Engineerin' that the techs have a new toy down in the shop, and it works good. That, son, is F. M.!"
The jump from theory to function can be a big one and seldom goes as planned.
Cheers,
Wes

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## pbehn (Dec 17, 2017)

XBe02Drvr said:


> Reminds me of the crusty old Chief Avionics Technician who woke us up on the first morning of antennas and transmission lines phase in A School.
> "Any you maggots got any clue to what the letters F M stand for?"
> (Class hotshot): "Sure, Chief that's Frequency Modulation, where the carrier wave is modu--"
> "Wrong, Sailor! You believe that bullpucky? What, you some kinda engineer or somethin? Any right thinkin' tweet knows it stands for f--kin' magic! You think those test rigs them engineers design with all their fancy formulas actually WORK when they build 'em? 'Course not! They tweak this and try that, and finally go back to their drawin' boards in  and tell the techs to tear down and dispose of the rig. Well no tech worth his salt tears down a perfectly good rig without first applying a little "FM" just to see what might happen. Sooner or later, word filters up to Engineering that the techs have a new toy down in the shop, and it works good. That, son, is F. M.!"
> ...


I was taught ultrasonic testing by a guy who pioneered it post war, his name still thows up results on google searches, C.J. Abrahams. Once in the practical class a guy said "I have found a defect" and got a prompt slap "upside the head". Mr Abrahams informed his student that he had found an indication, it is engineers who decide what is a defect, not technicians.

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## XBe02Drvr (Dec 17, 2017)

pbehn said:


> it is engineers who decide what is a defect, not technicians.


On a dark, pitching, wet, windswept deck, you're third in line for catapult two, on a hot scramble with bogies inbound and your AI radar fails its BIT checks, you've got more than an INDICATION! And no engineers to be found; you better hope your tech has his FM on.
Cheers,
Wes

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## wuzak (Dec 17, 2017)

wuzak said:


> As for funding, the hyper program was funded by the USAAC Materiel Division. The basic cylinder was developed by Sam Heron at Wright Field, Ohio.
> 
> Who did you think funded them?





Zipper730 said:


> That makes more sense actually...
> Well you said USAAC Material Division...



Huh?

In a previous post you said _they_ didn't have the money to develop so many engines. Who were the _they_ you were talking about?

In any case, I should have just said the USAAC funded the programs.




Zipper730 said:


> As for the cylinder-design: Why not just use an off the shelf cylinder while the new one is being developed? It might require restrictions on the engine, but at least the rest of the machinery can be run and ironed out.



What existing cylinder?

The Curtiss Conquerer/V-1570 from 1924?

You don't build a next generation engine based on last generation cylinder designs.




Zipper730 said:


> I understand that they funded them, but if you have budgetary problems -- you either have to throttle back all designs you have (and if you have a lot, all go to a crawl), throttle back some selectively (and risk getting accused of impropriety), or cut some designs and allocate funding to the best.



In the beginning there was only the Continental hyper engine supported by the USAAC. Lycoming started their development a year or two later, using their own funds for development until the USAAC started funding them a few years later.

Chrysler started their program some years later, not sure how they were funded.

In any case, the USAAC was initially funding only one hyper engine for the first few years.




Zipper730 said:


> So it had to go up a lot of layers to make approval or rejection; then go back down all those layers?
> Also, was this a 1-way system (Army tells them what to do, the company does it), or 2-way (Army tells them what to do, Company does it; Company submits ideas of their own/Army listens and tells them yes/no).



I don't know about the number of "layers", but funding had to be approved before Continental would move onto the next development stage.

Most likely 2 way, but he who signs the check has the last say.




Zipper730 said:


> I'm still surprised it took them so long to realize other engine developments at the time (NACA cowling for starters, improved radiator designs) meant the flat cylinder was unneded.



NACA cowlings held little interest for developers of in-line engines.

The theory with flat engines was that the engine could be buried in the wing of a multi-engine aircraft, and only a small protrusion carrying the prop shaft would be external. The theory was that the drag would be reduced in this manner.

It was found, however, that the difference between a normal nacelle and the buried configuration was minimal.

So, the Continental was developed into an inverted vee.

And Lycoming realised that the engine would not be powerful enough for future aircraft, so they put two of their flat 12s together to get the H-2470.


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## Zipper730 (Dec 17, 2017)

wuzak said:


> In any case, I should have just said the USAAC funded the programs.


Yeah...


> What existing cylinder?


That's a good point: I just was wondering if it was possible to use off the shelf components.


> In the beginning there was only the Continental hyper engine supported by the USAAC. Lycoming started their development a year or two later, using their own funds for development until the USAAC started funding them a few years later.


Okay, so Lycoming was partially on internal funds, and later on USAAC funding?


> Chrysler started their program some years later, not sure how they were funded.


Which engine was this?


> In any case, the USAAC was initially funding only one hyper engine for the first few years.


Okay...


> I don't know about the number of "layers", but funding had to be approved before Continental would move onto the next development stage.


Did this have to reach Congress each time?


> Most likely 2 way, but he who signs the check has the last say.


That's good


> The theory with flat engines was that the engine could be buried in the wing of a multi-engine aircraft, and only a small protrusion carrying the prop shaft would be external. The theory was that the drag would be reduced in this manner.


And the nacelle protrusion was minimal so it wasn't worth it. When did they realize this?


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## pbehn (Dec 17, 2017)

XBe02Drvr said:


> On a dark, pitching, wet, windswept deck, you're third in line for catapult two, on a hot scramble with bogies inbound and your AI radar fails its BIT checks, you've got more than an INDICATION! And no engineers to be found; you better hope your tech has his FM on.
> Cheers,
> Wes


Different fields and different discussions. What is a problem in one place, is not in others but sometimes is a disaster one time and one place. With regard to my post , what is defective is decided by engineers, I attach a link discussing a 6 inch crack in a pipeline. There is, I would stake my life on it no crack, especially a 6 inch crack in any pipeline. All pipe line specs are simple in this regard "No cracks are allowed" and that doesn't have a minimum size limit. On an operating pipe line no cracks can be allowed but in other areas of pipeline technology like pump stations they are allowed up to a certain limit and other technologies are developed to cope or monitor. The previously mentioned C.J. Abrahams developed fixed ultrasonic systems which monitor cracks to see if they are propagating or "as built" in a casting.

Pipeline which brings half of UK's North Sea oil is shut | Daily Mail Online


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## wuzak (Dec 17, 2017)

Zipper730 said:


> Did this have to reach Congress each time?



Doubt it went to Congress at all, except, maybe, for yearly appropriations.

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## wuzak (Dec 17, 2017)

Zipper730 said:


> Which engine was this?



This Beast.












Chrysler IV-2220 - Wikipedia

Which flew in this

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## Shortround6 (Dec 17, 2017)

The Army's "method" of funding these programs was to specify a certain goal or performance level. Like saying a test cylinder had to run at a certain level of power for a specified time. Let's assume a goal 75hp for the cylinder (ultimate goal would be about 100hp per cylinder) for 20 hours. If the engine failed ( broke connecting rod for example) at the 19th hour the Army would pay nothing until the engine was repaired, rebuilt and the test started again from zero hours and successfully completed. No extra funds would be paid for the rebuild or the extra hours of testing. Then the Army could decide the next test would be at the same level of power for more hours or raise the power level or decide that a bigger valves are required or some other change and issue a new contract with details of the new test. You could have a number of different tests/contracts in one year. 
Anything over and above what the Army wanted/ was willing to pay for, was at the manufacturer's risk. Like building a two cylinder test rig, very useful for figuring out the crankthrow and connecting rods on any engine using two cylinders per crankthrow. Army did move to two cylinder test rigs. 
Army apparently didn't think of the complications of sticking 6 pairs of cylinders together. To be fair a lot of engine designers failed to appreciate the complexities of adding cylinders or running engines at different rpms that originally designed for. Or the fact that higher rpm engines over more opportunity for harmonic vibration. As a result the army didn't "fund" a 12 cylinder engine until very late in the development cycle.

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## Zipper730 (Dec 18, 2017)

wuzak said:


> Doubt it went to Congress at all, except, maybe, for yearly appropriations.


Thanks


> Chrysler IV-2220 - Wikipedia


That engine started development in 1940: Which seems well after the Continental O-1230/IV-1430 and Lycoming O-1230 designs; Pratt & Whitney submitted several ideas as well right?



Shortround6 said:


> The Army's "method" of funding these programs was to specify a certain goal or performance level. Like saying a test cylinder had to run at a certain level of power for a specified time. Let's assume a goal 75hp for the cylinder (ultimate goal would be about 100hp per cylinder) for 20 hours. If the engine failed ( broke connecting rod for example) at the 19th hour the Army would pay nothing until the engine was repaired, rebuilt and the test started again from zero hours and successfully completed. No extra funds would be paid for the rebuild or the extra hours of testing. Then the Army could decide the next test would be at the same level of power for more hours or raise the power level or decide that a bigger valves are required or some other change and issue a new contract with details of the new test. You could have a number of different tests/contracts in one year.


I'm curious about two things: Firstly, how did the USN compare? Secondly: Could the US Army alter the contract partway along?


> Army apparently didn't think of the complications of sticking 6 pairs of cylinders together. To be fair a lot of engine designers failed to appreciate the complexities of adding cylinders or running engines at different rpms that originally designed for.


Why?


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## pbehn (Dec 18, 2017)

Shortround6 said:


> The Army's "method" of funding these programs was to specify a certain goal or performance level. Like saying a test cylinder had to run at a certain level of power for a specified time. Let's assume a goal 75hp for the cylinder (ultimate goal would be about 100hp per cylinder) for 20 hours. If the engine failed ( broke connecting rod for example) at the 19th hour the Army would pay nothing until the engine was repaired, rebuilt and the test started again from zero hours and successfully completed. No extra funds would be paid for the rebuild or the extra hours of testing. Then the Army could decide the next test would be at the same level of power for more hours or raise the power level or decide that a bigger valves are required or some other change and issue a new contract with details of the new test. You could have a number of different tests/contracts in one year.
> Anything over and above what the Army wanted/ was willing to pay for, was at the manufacturer's risk. Like building a two cylinder test rig, very useful for figuring out the crankthrow and connecting rods on any engine using two cylinders per crankthrow. Army did move to two cylinder test rigs.
> Army apparently didn't think of the complications of sticking 6 pairs of cylinders together. To be fair a lot of engine designers failed to appreciate the complexities of adding cylinders or running engines at different rpms that originally designed for. Or the fact that higher rpm engines over more opportunity for harmonic vibration. As a result the army didn't "fund" a 12 cylinder engine until very late in the development cycle.


Perhaps it wasn't immediately obvious that a demo of one or two cylinders working on a test bed gave very limited information on how a complete engine would work at 25,000 ft.

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## tomo pauk (Dec 18, 2017)

pbehn said:


> Perhaps it wasn't immediately obvious that a demo of one or two cylinders working on a test bed gave very limited information on how a complete engine would work at 25,000 ft.



Or even at all. 
Cue the Ford V-1650 - two cylinder test mule worked great, however the complete V12 produced less than half of projected power.


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## pbehn (Dec 18, 2017)

tomo pauk said:


> Or even at all.
> Cue the Ford V-1650 - two cylinder test mule worked great, however the complete V12 produced less than half of projected power.


Let me guess. The test mule was fed compressed air at room temperature and the mule wasn't driving the compressor?


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## tomo pauk (Dec 18, 2017)

Pretty much.
The supercharger was a gem, though, at least in idea (several patents were issued to the Ford people) - a 2-stage turbo-supercharger. Ie. there was no gear-driven supercharger stage, thus leaving more power for the prop.


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## Jugman (Dec 18, 2017)

There was only one engine called "HYPER" and that was the Continental I-1430. This turm has since come to mean any of the high performance liquid cooled engine of the period. But no period document will do so.

It should be noted that, unlike the other liquid cooled engines, the I-1430 was actually designed by the army. Continental was a subcontractor hired to build and develop the engine. This is why they spent four years on single cylinder testing. There was a considerable amount of extra red tape in the way.


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## pbehn (Dec 18, 2017)

In terms of developing an engine I believe the industry as a whole was learning about learning. It may have seemed reasonable to some to only finance one cylinder for research or possibly a twin, but for example Rolls Royce were developing the Crecy engine through the thirties and forties (a sleeve valve two stroke) by the time the project was abandoned a total of 6 complete V12 engines and 8 additional V twins had been made. I don't see how you can conduct long term reliability and short term maximum power tests on the same piece of "kit" doing one invalidates the other.

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## wuzak (Dec 18, 2017)

Engine development starts with a single cylinder development engine to this day.

The Crecy was based on Ricardo's single cylinder test engine, though with some changes.

The V2 development engines were produced to test the sleeve drive mechanism, which could not be done with a single cylinder engine. At least the first V2 was before the first V12.

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## wuzak (Dec 18, 2017)

Jugman said:


> There was only one engine called "HYPER" and that was the Continental I-1430. This turm has since come to mean any of the high performance liquid cooled engine of the period. But no period document will do so.
> 
> It should be noted that, unlike the other liquid cooled engines, the I-1430 was actually designed by the army. Continental was a subcontractor hired to build and develop the engine. This is why they spent four years on single cylinder testing. There was a considerable amount of extra red tape in the way.



The I-1430 was based on the Army's "hyper" cylinder design.

This meant hemi head and 2 valves per cylinder.

The O-1230/H-2470 was developed based on the same architecture, as was the Chrysler IV-2220.


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## pbehn (Dec 18, 2017)

wuzak said:


> Engine development starts with a single cylinder development engine to this day.
> 
> The Crecy was based on Ricardo's single cylinder test engine, though with some changes.
> 
> The V2 development engines were produced to test the sleeve drive mechanism, which could not be done with a single cylinder engine. At least the first V2 was before the first V12.


I don't doubt that at all, I was just making the point about the scale of research needed. Research may be based on single or twin cylinder prototypes but not just one and that research just gives background info for a multi cylinder engine.


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## Shortround6 (Dec 18, 2017)

Jugman said:


> There was only one engine called "HYPER" and that was the Continental I-1430. This turm has since come to mean any of the high performance liquid cooled engine of the period. But no period document will do so.
> 
> It should be noted that, unlike the other liquid cooled engines, the I-1430 was actually designed by the army. Continental was a subcontractor hired to build and develop the engine. This is why they spent four years on single cylinder testing. There was a considerable amount of extra red tape in the way.



The Lycoming may not have been referred to at the time as a "Hyper" engine but it was developed at almost the same time, to the same goals, using very similar architecture and principals. And by Continentals main rival. 
The Chrysler was around 8 years later and use somewhat larger cylinders. In fact the cylinder was about 1 cu in larger than a Merlin Cylinder  
I would agree that the Chrysler's claim to be a hyper engine is very, very dubious. 

I don't believe the Allison was ever referred to as a "Hyper" engine.


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## Shortround6 (Dec 18, 2017)

A lot of companies started with one cylinder test rigs. What happens after that depends on the engine. V-12s, V-8s, flat engines can get some good information from a two cylinder rig. The two cylinders act on one crank throw and will test the connecting rod and bearing set up. 
Radials see a lot less benefit from two (or three?) cylinder test rigs. P & W for example sometimes built one row test engines of two row radials as it allowed testing of the master rod/slave rod set up. and any vibration problems of the single row (adding the 2nd row introduced a whole bunch of new vibration problems) 
For the V-12 building a V-4 or V-6 won't really tell you much. The crankshafts will be too short and too stiff to reveal the problems that will show up with a full length crankshaft. 

I have no idea if RR ever built a 4 cylinder test rig for the Vulture.


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## Zipper730 (Dec 19, 2017)

pbehn said:


> Let me guess. The test mule was fed compressed air at room temperature and the mule wasn't driving the compressor?


The compressed air was to simulate flow off the supercharger?



tomo pauk said:


> The supercharger was a gem, though, at least in idea (several patents were issued to the Ford people) - a 2-stage turbo-supercharger. Ie. there was no gear-driven supercharger stage, thus leaving more power for the prop.


Fascinating idea...



Jugman said:


> There was only one engine called "HYPER" and that was the Continental I-1430.


I actually thought it applied to the O-1230/I-1430 and O-1230 as well...


> It should be noted that, unlike the other liquid cooled engines, the I-1430 was actually designed by the army. Continental was a subcontractor hired to build and develop the engine.


Why would somebody do this? It seems quite counterproductive...



wuzak said:


> The I-1430 was based on the Army's "hyper" cylinder design.
> 
> This meant hemi head and 2 valves per cylinder.
> 
> The O-1230/H-2470 was developed based on the same architecture, as was the Chrysler IV-2220.


Actually, many of the people at Continental quit and went to Lycoming


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## Jugman (Dec 19, 2017)

There was more to the hyper cylinder than the hemispherical combustion chamber. Only the O-1080/I-1430 actually used Heron's design. The hyper name _only _shows up in connection with the Continental engine in official correspondences and reports. None of the other engines ( such as the O-1230 or the R-2160) thought of today as hyper engines were ever called that. I don't know when this trend of calling all the high power experimental liquid-cooled engines hyper engines started, but it wasn't used during ww2.


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## pbehn (Dec 19, 2017)

Zipper730 said:


> The compressed air was to simulate flow off the supercharger?


Yes, but that is the problem, any simulation has gas flowing at a temperature, pressure and flow rate with a level of fuel to air mixture. The whole problem at the time was getting superchargers or turbos to deliver that level of flow, pressure and temperature at the optimum level of mixture at altitude. This apart from a single cylinder on a test bed bears only a passing resemblance to twelve of them linked together under a close fitting cowl at 25,000 ft. with one lubrication and cooling system.


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## Jugman (Dec 19, 2017)

Zipper how is it counterproductive? Wright field didn't have the engineering resources or manufacturing capacity to build an engine on there own. As a dedicated engine design and manufacturing company Continental had experience in doing this sort of deal for other companies.


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## pbehn (Dec 19, 2017)

Jugman said:


> Zipper how is it counterproductive? Wright field didn't have the engineering resources or manufacturing capacity to build an engine on there own. As a dedicated engine design and manufacturing company Continental had experience in doing this sort of deal for other companies.


Once war is declared every institution involved in military equipment are subcontractors and or project managers for the only client which is the government. Any institution connected to the government can hire the experts required to design something and commission some other organisation to put it into action. .


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## Shortround6 (Dec 19, 2017)

Jugman said:


> There was more to the hyper cylinder than the hemispherical combustion chamber. Only the O-1080/I-1430 actually used Heron's design. The hyper name _only _shows up in connection with the Continental engine in official correspondences and reports. None of the other engines ( such as the O-1230 or the R-2160) thought of today as hyper engines were ever called that. I don't know when this trend of calling all the high power experimental liquid-cooled engines hyper engines started, but it wasn't used during ww2.



Heron may have been gone by the time Continental was brought into the act.

Heron had designed an air cooled cylinder to be used on top of a Liberty crankcase and crankshaft. (or underneath, Allison made a small run of inverted air-cooled Liberty engines) but the smaller bore dropped displacement from 1650 to 1410 cubic inches. 5in reduced to 4 5/8ths. 

Early attempts to prove Riccardo wrong and the need for sleeve valves included building a water jacket around one of the cylinders from the air cooled Liberty and spraying water on the cylinder heads. The results were encouraging enough for the next step to be taken. A complete water jacket covering both cylinder walls and head. At this point they decided to shorten the stroke to allow for higher rpm. They selected a 5in stroke as this would give a displacement of 1008 cubic in (84 cu in per cylinder) for hyper cylinder #1. This was tested in 1933.In 1934 the Army had become worried that other engines of larger displacement might be more powerful than their engine and had Continental develop Hyper Cylinder #2 of 118.8 cu in inches or 1424 cu in for the complete engine. Stroke was kept the same but the bore went to 5.5 inches making this engine one of the few oversquare aircraft engines of the era. 
Work on the Lycoming started in the Fall of 1932 and the single cylinder test rig was running in the spring of 1934 and was of 102.8 cubic inches (5.25 bore X 4.75 in stroke) another over square engine. 
It was pretty much in direct competition to the Army/Continental engine while the Allison used larger displacement and less rpm as a path to power. 142.5 cu in cylinders.

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## wuzak (Dec 19, 2017)

Jugman said:


> There was more to the hyper cylinder than the hemispherical combustion chamber. Only the O-1080/I-1430 actually used Heron's design.



Yes, it was an oversquare cylinder, with a bore:stroke ratio of 1.1, whereas most of the time, like the Merlin and V-170, where undersquare (stroke bigger than bore).

It was also designed to run with high coolant temperatures - 300°F/149°C, though this was revised back to 250°F/121°C as it was realised that the reductions in radiator size were offset by the increases in the oil cooler size.




Jugman said:


> The hyper name _only _shows up in connection with the Continental engine in official correspondences and reports. None of the other engines ( such as the O-1230 or the R-2160) thought of today as hyper engines were ever called that. I don't know when this trend of calling all the high power experimental liquid-cooled engines hyper engines started, but it wasn't used during ww2.



That may be the case, but the O-1230, H-2470 and IV-2220 shared some general characteristics with the Hyper Cylinder.

Others, such as the R-2160, had less in common. And the Pratt & Whitney H-24 sleeve valve engines had nothing in common.


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## Zipper730 (Dec 20, 2017)

Jugman said:


> There was more to the hyper cylinder than the hemispherical combustion chamber. Only the O-1080/I-1430 actually used Heron's design. The hyper name _only _shows up in connection with the Continental engine in official correspondences and reports. None of the other engines ( such as the O-1230 or the R-2160) thought of today as hyper engines were ever called that.


Now that's interesting...


> Zipper how is it counterproductive? Wright field didn't have the engineering resources or manufacturing capacity to build an engine on there own. As a dedicated engine design and manufacturing company Continental had experience in doing this sort of deal for other companies.


That's not what I meant: I found it strange that Continental pretty much had the army draw up the blueprints, and they build it. Generally, one tells the manufacturer what they want, and occasionally stipulate certain things; then the contractor builds it and updates the buyer...



pbehn said:


> Yes, but that is the problem, any simulation has gas flowing at a temperature, pressure and flow rate with a level of fuel to air mixture. The whole problem at the time was getting superchargers or turbos to deliver that level of flow, pressure and temperature at the optimum level of mixture at altitude. This apart from a single cylinder on a test bed bears only a passing resemblance to twelve of them linked together under a close fitting cowl at 25,000 ft. with one lubrication and cooling system.


Couldn't you test the engine on a mountain? The US has some that go over 10,000


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## Shortround6 (Dec 20, 2017)

Zipper730 said:


> That's not what I meant: I found it strange that Continental pretty much had the army draw up the blueprints, and they build it. Generally, one tells the manufacturer what they want, and occasionally stipulate certain things; then the contractor builds it and updates the buyer...



The "Hyper Cylinder" got it's start in the experimental area of Wright Field. Sam Heron was working for them at the time. He left at some point in the Early 30s and by 1934 he held the position of Director of Aeronautical Research at the Ethyl Corporation (makers of the Tetraethyl Lead used in fuel).
But Wright Field didn't have the resources (casting/foundry equipment, large machine tools, etc) for engine fabrication. 
Unfortunately the Army was reluctant to give up their baby and in fact kept it on life support way too long. It wasn't canceled until 1944 or 45? 



> Couldn't you test the engine on a mountain? The US has some that go over 10,000



You could but why?
Dr Sanford Moss did test a turbo charger on Pike's Peak in 1918






But by 1940 most large aircraft engine manufacturers had test houses where they could control the atmosphere in terms of pressure/density and temperature to simulate high altitude flying. They could also pipe in pressurized air to test the basic engine (power section) and not be limited by supercharger development at certain stages in the program.

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## XBe02Drvr (Dec 20, 2017)

Zipper730 said:


> Couldn't you test the engine on a mountain? The US has some that go over 10,000


Get real, Zipper! Do you have any idea what an engine test cell entails? Or the difficulties and expense of building on a 10K+ mountaintop where there aren't any roads and the terrain is too steep for conventional construction equipment and it's the middle of a depression and an isolationist mentality nation isn't even convinced the need is there?? How about a couple of Sikorsky Skycranes? Piece of cake, right? GET REAL!!
I suggest you read up about the project of building a weather station on top of Mt. Washington in NH. And tatt was only a 6K mountain. And that was considered a national priority at the time.
And what relevance does a 10K test cell have to an engine whose target performance arena is 20-30K?
Cheers,
Wes


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## Jugman (Dec 20, 2017)

Continental didn't have the army do anything -well Continental _did_ have the army draw-up a signed contract for every expense made by Continental- the Army came up with the basic design and needed someone to make it.

Prewar there was no such thing as a "pay-as-you-go" R&D contract. _IF_ you had a contract with the services you had to deliver a discrete thing to them and it had to pass all contractual requirements. Then and only then would the funds be _authorized_ and if those funds aren't there, you may or may not actually get paid in the end. GM/Allison didn't break even on the V-1710 until around 1942. That's twelve years into the project with sales much higher than one could have expected prewar.

With this in mind, I think, at least initially, the O-1430 was meant as nothing more than an experiment. There is no easy way to do this under the system that was in place at the time. By doing much of the design in-house, the army could get exactly what they wanted cheeper and faster. Well in theory they could. This obviously didn't happen and the hyper engine had one of the most, if not the most, protracted development cycles
of any engine of the era.


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## Shortround6 (Dec 20, 2017)

Add ended up as junk. 

The amount of strength needed in the crankshaft/crankcase may have been severely underestimated in a number of engines as power grew due to boost or increase rpm. The separate cylinder construction became a bigger liability as engine power went up.


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## Zipper730 (Dec 20, 2017)

XBe02Drvr said:


> Get real, Zipper! Do you have any idea what an engine test cell entails? Or the difficulties and expense of building on a 10K+ mountaintop where there aren't any roads and the terrain is too steep for conventional construction equipment and it's the middle of a depression and an isolationist mentality nation isn't even convinced the need is there??


I'd almost swear there was a case where an engine of some sort was run on a mountain...



Jugman said:


> Continental didn't have the army do anything -well Continental _did_ have the army draw-up a signed contract for every expense made by Continental- the Army came up with the basic design and needed someone to make it.
> 
> Prewar there was no such thing as a "pay-as-you-go" R&D contract.


When did that start?


> With this in mind, I think, at least initially, the O-1430 was meant as nothing more than an experiment. There is no easy way to do this under the system that was in place at the time.


What about NACA? They were equipped for experiments...


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## pbehn (Dec 20, 2017)

Zipper730 said:


> I'd almost swear there was a case where an engine of some sort was run on a mountain...
> 
> When did that start?
> What about NACA? They were equipped for experiments...


Yes Zipper, but that is not true science. You can run an engine at 10,000 ft up a mountain but what does that tell you? You need it to be in its air frame with its cooling system, breathing system etc. You need to build a wind tunnel that supplies air to completely simulate conditions at 10,000 ft, but at the time there were no real problems at that level, you cannot build facilities at 20-25,000 ft because people die there and it costs a fortune. The solution is more research and more science, Aeroplane and its engine technology moved at a lightening pace between 1910 and 1940, from airplanes being designed in back rooms and built in garages to having all the worlds government throwing money at all its issues. NACA aerofoil profiles were not a private venture.

The trick is to find out what you can discover from a test like a single cylinder prototype and what you cant.

Stanley Hooker who made big strides in the development of supercharger for Rolls Royce also has this in his Wikipedia page,

"One major outcome of his work introduced a generalised method of predicting and comparing aircraft engine performance under flight conditions. The status of this work was summarised in an internal Rolls-Royce Report in March 1941 and made public by the Rolls-Royce Heritage Trust in 1997.[7]"

That is how science works, you find out what you know and what you can extrapolate from that and also what you cant. A single cylinder tells you some things about an engines performance but very little about how twelve or more linked together will do.

The P 51 was designed with the best aerodynamics known at the time, but after introduction its engine air inlet, its cooling air inlet and its tail were modified, that does not mean mistakes were made that means they did not know everything but did their best with what they knew.

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## Shortround6 (Dec 20, 2017)

Zipper730 said:


> I'd almost swear there was a case where an engine of some sort was run on a mountain...


 See above posts. 

Going on "location" helped in 1918 but you still have a truck load of variables.
Temperature on some of those mountains can change 20-30 degrees in just a few hours. Air density is not constant any more than it is constant at sea level. Dealing with rain or snow sure isn't going to speed things up either. In the high mountains it can snow in the summer. Doesn't stay but screws up any tests scheduled for that day. They had 15-22 years to develop climate controlled test labs right on the factory grounds after 1918 to help eliminate the variables and permit a test schedule that was more independent of the weather. 
It made getting spare parts easier in case something broke. 





Instead of us spoon feeding it to you;
Superchargers

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## Jugman (Dec 21, 2017)

I don't know the exact date "pay-as-you-go" was initiated but I do know that the R-4360 the first engine project to use it. Also with this system all IP rights were transferred to the military. At least as far as manufacturing right were concerned. 


NACA wasn't setup to do, nor was it their mission to do the kind of work the army needed.

SR6 I agree the use of completely separate cylinders was a bad idea . For poppet-valve engines the loss of a mono head and the rigidity it provides is much to pass up. For sleeve-valve engines I actually thing they're an improvement as you have all the disadvantages -and them some- anyways.


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## pinsog (Dec 21, 2017)

XBe02Drvr said:


> Get real, Zipper! Do you have any idea what an engine test cell entails? Or the difficulties and expense of building on a 10K+ mountaintop where there aren't any roads and the terrain is too steep for conventional construction equipment and it's the middle of a depression and an isolationist mentality nation isn't even convinced the need is there?? How about a couple of Sikorsky Skycranes? Piece of cake, right? GET REAL!!
> I suggest you read up about the project of building a weather station on top of Mt. Washington in NH. And tatt was only a 6K mountain. And that was considered a national priority at the time.
> And what relevance does a 10K test cell have to an engine whose target performance arena is 20-30K?
> Cheers,
> Wes



Sir, I would imagine Zipper is a younger person that doesn’t have the experience or knowledge of the rest of the group. Instead of berating him and talking down to him, try talking to him like he’s your grandson. Obviously he is interested and would like to learn, so let’s be kind and teach him, enjoy the opportunity to pass on your knowledge. Remember that none of us was born knowing anything, we all had to learn 1 step at a time.

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## fubar57 (Dec 21, 2017)

@pinsong read all the rest of his posts with _*multiple bloody quoting*_, quite frustrating and annoying. Plus he has been warned about it from the Mods on at least 2 occasions. Almost destroys the threads that I am interested in learning from. Much of what he asks can be found in less than a second using Google


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## pinsog (Dec 21, 2017)

Fubar57, you certainly have a point and I have seen some that wouldn’t or couldn’t learn. I guess I just try to work pretty easy with anyone and everyone, that whole ‘I talk to others like I want to be talked to’ thing.


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## XBe02Drvr (Dec 21, 2017)

Pinsog, your point is well taken, and I apologise. As Fubar says, we have a history with our Zipper, and sometimes go a little over the top in dealing with his questions. Thanks for calling me on it. I was out of line.
Cheers,
Wes

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## pinsog (Dec 21, 2017)

XBe02Drvr said:


> Pinsog, your point is well taken, and I apologise. As Fubar says, we have a history with our Zipper, and sometimes go a little over the top in dealing with his questions. Thanks for calling me on it. I was out of line.
> Cheers,
> Wes



Thank you sir. We can all get annoyed sometimes. Have a good day.


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## wuzak (Dec 21, 2017)

Jugman said:


> I don't know the exact date "pay-as-you-go" was initiated but I do know that the R-4360 the first engine project to use it. Also with this system all IP rights were transferred to the military. At least as far as manufacturing right were concerned.



Is that true?

I thought that the R-4360 was a private venture that was supported by the military.


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## Jugman (Dec 21, 2017)

Initially it was but Congress didn't like the idea of the services footing the r&d bill and industry reaping the rewards. 

As the system worked in the UK prewar and during the war, it was next to impossible to lose money on R&D once government funding was secured. So they weren't completely out of line.

But like I said I'm not sure exactly how much IP was given away. White says all of it but he doesn't say if P&W retained any rights to it.


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## pbehn (Dec 21, 2017)

Jugman said:


> Initially it was but Congress didn't like the idea of the services footing the r&d bill and industry reaping the rewards.
> 
> As the system worked in the UK prewar and during the war, it was next to impossible to lose money on R&D once government funding was secured. So they weren't completely out of line.
> 
> But like I said I'm not sure exactly how much IP was given away. White says all of it but he doesn't say if P&W retained any rights to it.


If you read the history of Frank Whittle and the UK development of jet engines it is almost impossible to tell the difference between state and private investment and while USA spending on the military was higher than the UKs the percentage of state spending was much higher in UK, in the UK during the war the government controlled everything. Whittle worked for the RAF but had to form a company whos only possible clients were the government.


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## Peter Gunn (Dec 22, 2017)

Shortround6 said:


> *SNIP*
> 
> Instead of us spoon feeding it to you;
> Superchargers



Excellent link, the pictures alone are a treasure, I love when a project is well documented photographically. Thanks again.


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## pinsog (Dec 22, 2017)

Instead of us spoon feeding it to you;
Superchargers[/QUOTE]

Cool article. Love the pics. I bet the driver was wishing that old truck was turbocharged before he got to the top of Pikes Peak!!! (Truck running wide open, in gear as driver walks beside it smoking a cigarette)

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## Zipper730 (Dec 22, 2017)

pbehn said:


> Yes Zipper, but that is not true science. You can run an engine at 10,000 ft up a mountain but what does that tell you?


During early testing it would give a basic idea of what the engine would do at different altitude if there were an inadequate number of test-celles


> The trick is to find out what you can discover from a test like a single cylinder prototype and what you cant.
> 
> Stanley Hooker who made big strides in the development of supercharger for Rolls Royce also has this in his Wikipedia page,
> 
> "One major outcome of his work introduced a generalised method of predicting and comparing aircraft engine performance under flight conditions.


From what I read: He joined RR in 1937, started working on superchargers in 1938.



Shortround6 said:


> Going on "location" helped in 1918 but you still have a truck load of variables.


Good point


> They had 15-22 years to develop climate controlled test labs right on the factory grounds after 1918 to help eliminate the variables and permit a test schedule that was more independent of the weather.


We had test cells available in 1933?



Jugman said:


> I don't know the exact date "pay-as-you-go" was initiated but I do know that the R-4360 the first engine project to use it.


Not sure when the design started but it might have been around 1942: It was first run in 1944...


> Also with this system all IP rights were transferred to the military. At least as far as manufacturing right were concerned.


Did that change?


> NACA wasn't setup to do, nor was it their mission to do the kind of work the army needed.


That's true, but...

NACA's job was to develop the field of aerospace engineering and propulsion engineering
Their work generally was based on coming up with new airfoil/airframe, new engineering and engine concepts: They did however test ideas out.



pinsog said:


> Sir, I would imagine Zipper is a younger person that doesn’t have the experience or knowledge of the rest of the group.


I'm 34


> Obviously he is interested and would like to learn


Correct


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## pinsog (Dec 22, 2017)

Hello Zipper. I’m 47. I think many of these guys are retired and a lot of them are in the aerospace industry or ex military. I’ve learned tons myself. Listen to them, research on your own and ask questions on stuff you don’t understand. Above all, enjoy yourself!!!! Have a great day

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## Jugman (Dec 22, 2017)

Zipper730 said:


> Not sure when the design started but it might have been around 1942: It was first run in 1944...



The official start date for the R-4360 was in November 1940. Major funding came some time later.



> Did that change?



It has been modified but I have no knowledge with regards to when or why.



> That's true, but...
> 
> NACA's job was to develop the field of aerospace engineering and propulsion engineering
> Their work generally was based on coming up with new airfoil/airframe, new engineering and engine concepts: They did however test ideas out.




NACA's job was to advance the theory of flight not to apply it to practical everyday problems. The army needed expertise in the latter. In any event NACA didn't have the kind of facilities to build an engine from scratch.

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## pbehn (Dec 22, 2017)

Zipper730 said:


> During early testing it would give a basic idea of what the engine would do at different altitude if there were an inadequate number of test-celles
> From what I read: He joined RR in 1937, started working on superchargers in 1938.



The real advantage of running a test up a mountain at 10,000ft is the ability to strap as many sensors on it as you can manage and record their readings. Thermocouples, thermometers, surface pyrometers, barometers, flow meters etc which cannot be done on an aircraft. This is how things work, the information learned will have been used to improved understanding of how engines work and what works at all altitudes.

Hooker was (as another poster pointed out) a mathematician who also studied hydro and fluid dynamics at university. He started working on the Merlin Supercharger initially in response to a request from the Air Ministry for a turbocharged Merlin to power a high altitude Wellington bomber/recon aircraft. His work or the Merlin supercharger initially produced the Merlin 45 and then the 61, but he was a mathematician and an engineer, his improvements to the Merlin were not from years of getting his hands dirty but really knowing the subject of compressing and moving gases in engines, which was equally applicable to jet engines.

The world was changing at a remarkable rate. In 1903 when the Wright Brothers first flew an airplane, Henry Ford also started his car company after leaving what would become Cadillac in the next decade engine production would have passed 1 million units.. You could say that the Wright brothers with their mechanic were the only proven experts in aviation engineering, only 15 years later at the end of the first world war there were more aviation companies and aircraft engine manufacturers than you could wave a stick at. 

!903 was also the year that Stanford Moss wrote his thesis on turbo supercharging


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## MiTasol (Dec 22, 2017)

pinsog said:


> Try talking to him like he’s your grandson. Obviously he is interested and would like to learn, so let’s be kind and teach him, enjoy the opportunity to pass on your knowledge. Remember that none of us was born knowing anything, we all had to learn 1 step at a time.



Right on!!

For the benefit of the many who do not understand the basics of engine design and its direct relationship to aircraft design I recommend reading the 1943 Allison Engine Company publication _*Engine design as related to airplane power : with particular reference to performance at varying altitudes *_which I have just posted at Engine design as related to airplane power : with particular reference to performance at varying alt

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## GregP (Dec 27, 2017)

Very nice article, MiTasol. Thanks!


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## swampyankee (Dec 28, 2017)

I believe that the government still owns the rights to IP paid for with tax money; the DoD can walk over to Pratt or GE and tell either to help the other build either F-22 or F-35 engines, as was done with the F101 engine the F-18.


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## Zipper730 (Jan 3, 2018)

Shortround6 said:


> But by 1940 most large aircraft engine manufacturers had test houses where they could control the atmosphere in terms of pressure/density and temperature to simulate high altitude flying.


While this might sound silly, did any have even basic test-cells prior to that? 

It's just as a sort of time table to figure out what was do-able when...



Jugman said:


> The official start date for the R-4360 was in November 1940.


Thanks! It's nice to be able to have exact (or close to exact) numbers (other members will attest to this).


> NACA's job was to advance the theory of flight not to apply it to practical everyday problems.


I suppose you're right, this is more an applied research area than a theoretical one.

There was something I was reading in an online PDF file which had to do with aircraft fuels and the methods by which aircraft and engine projects were managed in the US & UK.

One of the things that was mentioned was that certain decisions could be made by subordinates, and didn't have to be made from the top: Why wasn't that the case in the US?


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## Zipper730 (Jan 3, 2018)

swampyankee said:


> I believe that the government still owns the rights to IP paid for with tax money


I remember, there was a big hubbub in the 1950's when the F-104 was being built and the USAF wanted to make it their default fighter and Lockheed fought it tooth and nail: It seemed to be an IP issue and frankly, I'm not sure I understand what the problem was: There were construction pools made during WWII and even Korea. I remember you'd see numerous cases of different manufacturers building aircraft (some B-47's were built by Douglas).

I was curious if that changed anything in the big scheme: I don't remember seeing these pools existing anymore by Vietnam or after.


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## XBe02Drvr (Jan 3, 2018)

WWII was a total war national emergency and some of the practices of industrial competition were overridden by wartime needs. This mindset continued for awhile afterwards to a certain extent through the Korean conflict. By the time Vietnam rolled around it was competition as usual and as it was a "guns and butter" war, there was no overriding national emergency.
There still was quite a bit of spreading around of production, but it was in the form of contractors building subassemblies and the manufacturer doing final assembly. Building something as complex as an F4 entirely under one roof would require an impossibly huge and unwieldy plant.
Cheers
Wes


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## swampyankee (Jan 3, 2018)

When I worked at Lycoming in the early 1980s, the Army threatened to pull AGT-1500 production. At that time, GE and Lycoming had a very bitter relationship, and GE had a bigger lobbying budget.


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## Zipper730 (Jan 6, 2018)

XBe02Drvr said:


> WWII was a total war national emergency and some of the practices of industrial competition were overridden by wartime needs.


Which continued through to Korea...


> By the time Vietnam rolled around it was competition as usual and as it was a "guns and butter" war, there was no overriding national emergency.


The F-104 had nothing to do with this?


> There still was quite a bit of spreading around of production, but it was in the form of contractors building subassemblies and the manufacturer doing final assembly.


It is weird that you don't have many contractors building one plane though... that seemed to have ended at some point in the 1950's...



swampyankee said:


> When I worked at Lycoming in the early 1980s, the Army threatened to pull AGT-1500 production. At that time, GE and Lycoming had a very bitter relationship, and GE had a bigger lobbying budget.


So, GE won?


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## swampyankee (Jan 6, 2018)

Zipper730 said:


> Which continued through to Korea...
> The F-104 had nothing to do with this?
> It is weird that you don't have many contractors building one plane though... that seemed to have ended at some point in the 1950's...
> 
> So, GE won?



In this case, no. I think the Army was using it more as a threat during contract negotiations.


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## Shortround6 (Jan 6, 2018)

I believe the M-16 rifle was one of the few modern weapons to be built in multiple factories (although the M-14 was also), 
strange as politics and government contracts are the Government (army) wanted more than one source during the vietnam war, which is understandable. 
However Colt had to turn over not only blueprints of the rifle but information on tools, jigs, manufacturing procedures/techniques and so on. The two other companies that built the M-16 at the time (everybody with lathe in the garage seems to be building them now) both charged more per rifle than Colt. One company charged almost double what Colt was getting per rifle in contract at the same time. 
The strange part (and politics) comes in when at least one senator wanted to investigate Colt for excessive profits but not the other companies.


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## swampyankee (Jan 6, 2018)

Shortround6 said:


> I believe the M-16 rifle was one of the few modern weapons to be built in multiple factories (although the M-14 was also),
> strange as politics and government contracts are the Government (army) wanted more than one source during the vietnam war, which is understandable.
> However Colt had to turn over not only blueprints of the rifle but information on tools, jigs, manufacturing procedures/techniques and so on. The two other companies that built the M-16 at the time (everybody with lathe in the garage seems to be building them now) both charged more per rifle than Colt. One company charged almost double what Colt was getting per rifle in contract at the same time.
> The strange part (and politics) comes in when at least one senator wanted to investigate Colt for excessive profits but not the other companies.



Where was that senator from?

During the F-18 production, I believe in the Reagan Administration, somehow, Pratt & Whitney got the DoD to open them up as a second source. I don't know why this was decided, but I'm 99% sure that lobbying was involved, although I don't know if it was lobbying congress or lobbying the executive branch.


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## XBe02Drvr (Jan 7, 2018)

Zipper730 said:


> It is weird that you don't have many contractors building one plane though... that seemed to have ended at some point in the 1950's...


What's weird about it? The weird thing is aircraft companies building their competitors designs. Nobody wants to devote precious production capacity to build their competitors airplane instead of their own. That's the quick way to "also ran" status in the highly competitive aircraft industry.


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## Zipper730 (Jan 7, 2018)

swampyankee said:


> In this case, no. I think the Army was using it more as a threat during contract negotiations.


It's funny how the Army & Navy have a legendary rivalry, but they'll team together gladly to stick it to the Air Force...


> During the F-18 production, I believe in the Reagan Administration, somehow, Pratt & Whitney got the DoD to open them up as a second source.


Interesting...


> I don't know why this was decided, but I'm 99% sure that lobbying was involved, although I don't know if it was lobbying congress or lobbying the executive branch.


I usually assume it's lobbyists -- follow the money right? However, it's hard to tell honestly...



Shortround6 said:


> I believe the M-16 rifle was one of the few modern weapons to be built in multiple factories (although the M-14 was also), strange as politics and government contracts are the Government (army) wanted more than one source during the vietnam war, which is understandable.


So it was a matter of need and redundancy, and the US Army thought differently than the USAF?


> However Colt had to turn over not only blueprints of the rifle but information on tools, jigs, manufacturing procedures/techniques and so on.


Was this the intellectual property issue Lockheed managed to raise a whole stink on?


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## Zipper730 (Jan 7, 2018)

XBe02Drvr said:


> What's weird about it?


It was a common practice that continued for some time, then *pfft* disapeared.


> The weird thing is aircraft companies building their competitors designs. Nobody wants to devote precious production capacity to build their competitors airplane instead of their own.


Of course, but I'd figure it would homogenize the knowledge base: Effectively, everybody is kept knowledgeable.


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## XBe02Drvr (Jan 7, 2018)

Zipper730 said:


> It was a common practice that continued for some time, then *pfft* disapeared.
> Of course, but I'd figure it would homogenize the knowledge base: Effectively, everybody is kept knowledgeable.


It was never a natural or comfortable practice in an industry that had traditionally been cutthroat competitive. It was imposed by the government due to the national emergency of the war. Yes it did "homogenize the knowledge base", but that was of benefit only to the government, as aircraft companies viewed the "knowledge base" as proprietary property. New information that companies were given to enable them to manufacture their competitors plane was usable only for that purpose. They were not allowed to use it in their own designs.
Cheers
Wes


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## Zipper730 (Jan 7, 2018)

XBe02Drvr said:


> It was never a natural or comfortable practice in an industry that had traditionally been cutthroat competitive.


Of course, but they were supposed to serve their country in time of war...


> It was imposed by the government due to the national emergency of the war. Yes it did "homogenize the knowledge base", but that was of benefit only to the government, as aircraft companies viewed the "knowledge base" as proprietary property.


True enough, ironically the requirements might very well have provided a balancing force. It's dangerous if either government (USSR from 1917-1991) or business (Italy from 1919 to 1943, Germany from 1933 to 1945) get too powerful.


> New information that companies were given to enable them to manufacture their competitors plane was usable only for that purpose. They were not allowed to use it in their own designs.


You're telling me that defense contractors *never* used this knowledge for their own projects officially/unofficially?


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## XBe02Drvr (Jan 7, 2018)

Zipper730 said:


> You're telling me that defense contractors *never* used this knowledge for their own projects officially/unofficially?


Did you ever hear of a prohibition such as this being embraced and scrupulously adhered to? Of course not!. It has to be enforced just like enforcement of the original Prohibition (of alcohol) and with about the same lack of success. Do you wonder that companies hated being forced to share their hard-won techniques and technical data with their competitors? They had to expend a lot of effort in defending their intellectual property. As they saw it, their fiduciary responsibility to their stockholders was closer to their hearts than any extrapolated patriotic impulses.
Cheers,
Wes


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## XBe02Drvr (Jan 7, 2018)

Zipper730 said:


> It's funny how the Army & Navy have a legendary rivalry, but they'll team together gladly to stick it to the Air Force...


Considering the high-handed way the infant Air Force treated the senior services, are you surprised? No sooner had they achieved Independence, than they started lobbying Congress to abolish the other two services as obsolete and make their remnants subsidiaries of the almighty USAF. Are you surprised the other two services had it in for the Air Force? The Air Force tried to take over Naval and Army aviation similar to the prewar RAF model. And they almost succeeded.
Cheers,
Wes


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## swampyankee (Jan 7, 2018)

XBe02Drvr said:


> What's weird about it? The weird thing is aircraft companies building their competitors designs. Nobody wants to devote precious production capacity to build their competitors airplane instead of their own. That's the quick way to "also ran" status in the highly competitive aircraft industry.



On the other hand, it's guaranteed profits* (virtually all contracts with the US government are; this is a major reason why Lockheed-Martin, Northrop-Grumman, and General Dynamics have essentially no non-government business). Pre-WWII, a company could win a design contract and lose the production contract which was, of course, a much larger prize.



* Although Brewster couldn't manage even that. It must take a particular bad of stupid for the executives of a company _making military aircraft _to fail during wartime.


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## Zipper730 (Jan 8, 2018)

XBe02Drvr said:


> Did you ever hear of a prohibition such as this being embraced and scrupulously adhered to? Of course not!


Thought so...


> It has to be enforced


And the only way it'd ever work is if the odds of being caught were almost 100% and the penalties were fairly stiff.


> Do you wonder that companies hated being forced to share their hard-won techniques and technical data with their competitors?


No, not at all: They did a lot of work to develop it.


> As they saw it, their fiduciary responsibility to their stockholders was closer to their hearts than any extrapolated patriotic impulses.


Well, I figure most CEO's see it as a matter of benefiting themselves first, then stockholders, and if there's any time left, that whole patriotic thing (yeah, I know -- that's kind of cynical, but I should point out that many corporations during WWII did, indeed, knowingly and deliberately, engage in trade with the enemy).


> Considering the high-handed way the infant Air Force treated the senior services, are you surprised? No sooner had they achieved Independence, than they started lobbying Congress to abolish the other two services as obsolete and make their remnants subsidiaries of the almighty USAF.


That's not too far off (and frankly, an excellent summary).


> The Air Force tried to take over Naval and Army aviation similar to the prewar RAF model. And they almost succeeded.


Actually, the RAF at least let the Navy keep their carriers: The USAF wanted to sink every last one (as well as much of the surface fleet).



swampyankee said:


> On the other hand, it's guaranteed profits* (virtually all contracts with the US government are; this is a major reason why Lockheed-Martin, Northrop-Grumman, and General Dynamics have essentially no non-government business). Pre-WWII, a company could win a design contract and lose the production contract which was, of course, a much larger prize.


Even if the design doesn't live up


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## tyrodtom (Jan 8, 2018)

Zipper730, you have a tendency to include little snipppets of information that often turn out to be bs when examined closer.

You need to expand on your claim that many corporations knowingly and deliberately engage with trade with the enemy.


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## Shortround6 (Jan 8, 2018)

And simply having factories in enemy/occupied countries doesn't really cut it. 
How much communication was there between Ford of Germany and Ford of France with Ford In the US _after _Dec 10th 1941 for example. 
And those factories could not simply close their doors and send all the workers home once Germany declared war on the US.


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## Zipper730 (Jan 8, 2018)

tyrodtom said:


> You need to expand on your claim that many corporations knowingly and deliberately engage with trade with the enemy.


Okay...

IBM: Ran a subsidiary called "Dehomag" which was used for making punched-card machines. This was used to help facilitate taking census in occupied territories (as well as ones they already controlled), and was used to help facilitate the Holocaust. IBM was told that this technology was being used to facilitate the war-effort as of 1942. They did nothing.

Ford: Build trucks for the German government. Henry Ford was an ardent supporter of the Nazi's, so even if he had the ability to stop things, he would not have.

Coca-Cola: Well, they didn't do it directly, they created a company called "Fanta". Most people think of orange soda, or possibly grape soda. Originally Fanta was basically Coca Cola made with German ingredients in Germany. This was started in '33 but continued at least into 1942 or 1943 when the war was on.


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## Shortround6 (Jan 8, 2018)

OK, and how, pray tell, was IBM in America going to *stop *Dehomag in Germany from cooperating with the German government/nazis? 

Same with Ford.

Same with Fanta.

Ford of Germany tells the German government "no we won't build any more trucks for you" German official sends 5-10 top managers to concentration camp and asks the remaining managers if they want to to reconsider. Workers are told make trucks or "join" the army. 

The "Home" office has very little control of what a plant in a foreign country does or does not do once war is declared between the two countries. 
Blaming the home office or claiming they "traded" with the enemy it a pretty bogus position.
IF old Henry loaded a freighter with American made (or even Brazilian made Fords) and sailed them to Germany to help the German war effort that would be a different story. Or even if they sent a courier with blue prints of latest improvements to basic engine.

Many French companies made parts/equipment for the Germans after being occupied, does that mean they " knowingly and deliberately engage with trade with the enemy." in a negative sense? 
Yes they knowingly and deliberately engaged in trade with the occupiers of their country but the alternative was death or exile for both management and workers and looting/destruction of the factories. 

Gnome Rhone was a rather classic example. They built a lot of engines for the Germans but it was estimated that they built only about 25% of their potential capacity (or what the Germans thought they could make) which was just enough to keep the Germans from ordering "reprisals" or looting the Factory and sending the machine tools elsewhere. It also kept the workers in France and not drafted into auxiliary labor battalions.


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## XBe02Drvr (Jan 8, 2018)

Zipper730 said:


> Actually, the RAF at least let the Navy keep their carriers: The USAF wanted to sink every last one (as well as much of the surface fleet).


Who needs carriers and a surface fleet when you can have Peacemakers, Stratojets, and THE BOMB instead? It's a no-brainer, right? With "giv'em hell Harry" carrying "the football" and Curt Lemay managing the team, we can keep the entire world too terrified to give us a hard time anywhere any time.
Isn't that our manifest destiny?
Cheers,
Wes


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## XBe02Drvr (Jan 8, 2018)

Zipper730 said:


> And the only way it'd ever work is if the odds of being caught were almost


My dad (4F, unfit for combat) worked as a DCAS (Defense Contract Assurance Service) inspector at Bell in Niagara, NY during the changeover from P39 to P63 production. Part of his job was monitoring the inclusion of technologies that were Intellectual Property of other companies in Bell products. This was a job that needed an engineer, not an English teacher, but engineers were not to be had for what the government would pay, especially since the job didn't come with a draft deferment. He wound up mostly just patrolling for deliberate wastage to up the cost of production (cost-plus contract). He said some of the Soviet liason officers (decorated combat pilots to a man) were mighty colorful characters. They would randomly pick a new plane out of production flight test and go out terrorizing the countryside. (Especially Curtiss production test at nearby Buffalo International!) Naturally they would choose one that didn't have red stars on it yet.
Cheers,
Wes

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## GregP (Jan 8, 2018)

Interesting as it might be, what has any of this to do with XP-65 / F7F Development?


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## XBe02Drvr (Jan 8, 2018)

Sorry Greg, dratted crosswind, drifted off course again! No excuse, sir.
Cheers,
Wes


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## Zipper730 (Jan 8, 2018)

XBe02Drvr said:


> Who needs carriers and a surface fleet when you can have Peacemakers, Stratojets, and THE BOMB instead?


Firstly, nuclear bombs are a weapon only to be used in total war. Wars have various sizes from minor conflicts to world-scale conflicts.

Carriers come into their own in wars that are small/moderate scale where nuclear bombs are not really all that practical: Regardless, the carriers were able to launch aircraft (P2V's and AJ's) off their decks which could carry nuclear bombs (the AJ could be recovered) in a total-war setting, and could carry large numbers of aircraft with conventional ordinance off the coast of an enemy nation. At the start of a war, the carriers are useful because most bombers required some form of escort unless they operated at night, and nearby air-bases might very well be under another nations control and require some negotiation for agreed upon terms of use (a carrier presents no such restriction as long as it stays in international waters).

There is also a general reluctance among politicians to use nuclear weapons unless faced with the imminent threat of attack, or while already embroiled in a war of substantial size: This basically means that when bombers are to be used, they will be carrying conventional ordinance, and because of this, they will need to be employed in massed raids, in large numbers.
Because large aircraft burn up more fuel than small aircraft, and large numbers of large aircraft burn up even more fuel yet, the carrier is actually fairly fuel economical as well: Firstly, because the aircraft are quite small, fly relatively short durations, and require quite a number of missions to equal the fuel consumption of one bomber flying one mission; Secondly, compared to aircraft, ships are fuel efficient for the amount of fuel they burn relative to mass over range: An entire task force might very well use less fuel than a protracted series of city-busting raids carried out over and over again.

The only question remaining is can a carrier defend against a bomber-attack? The Russians WWII vintage bombers weren't all that capable in performance, even if in range; the Tu-4 could get into the 30,000 foot range presumably, where we could still take them out; the B-36 was not really a valid comparison, though they'd end up fielding jet-powered aircraft.


> It's a no-brainer, right? With "giv'em hell Harry" carrying "the football" and Curt Lemay managing the team, we can keep the entire world too terrified to give us a hard time anywhere any time.


Keeping the world terrified of you motivates them to figure out how to counter the threat you pose; this in turn requires you to develop ever more advanced and destructive weapons to carry out the threat, as well as defend against enemy developments.

While it might work out in theory, but it's economically ruinous (basically we won the Cold War because the Soviet Union could not take the economical abuse), and crazy dangerous: As weapons systems become more capable, faster responding, and overall faster, it just takes one wrong move to basically wipe out entire nations worth of real-estate and irradiate much of the Northern Hemisphere.


> Isn't that our manifest destiny?


Manifest Destiny was the belief that it was God's will for America to expand all the way to the Pacific Ocean. This would be expanding the position to conquer the world. Manifest Destiny as it was wasn't well liked by Native Americans and Mexicans, and inserting our noses into the affairs of other nations has created all sorts of problems that are plaguing us to this day.


Shortround6 said:


> OK, and how, pray tell, was IBM in America going to *stop *Dehomag in Germany from cooperating with the German government/nazis?


They could cut off financial aid


> Same with Ford. Same with Fanta.


The same rule applies


> Ford of Germany tells the German government "no we won't build any more trucks for you" German official sends 5-10 top managers to concentration camp and asks the remaining managers if they want to to reconsider.


Well, that's their choice if they wish to reconsider: Under threat of death, I wouldn't necessarily hold it against them if they did; I would hold it against a corporation who continued to supply aid.


> Many French companies made parts/equipment for the Germans after being occupied, does that mean they " knowingly and deliberately engage with trade with the enemy." in a negative sense?


Their whole country is under direct occupation -- they are in a situation where they are forced to comply or risk death. We weren't occupied, and could have cut aid.



GregP said:


> Interesting as it might be, what has any of this to do with XP-65 / F7F Development?


That's a good point


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## swampyankee (Jan 8, 2018)

I _suspect_ that the defense contractors rarely traded directly with the enemy, at least during declared war, but US companies were likely to have knowingly sold military and dual-use products to intermediaries who were trading with the USSR during the Cold War, Iran during the Hostage Crisis, and other places. 

Holding foreign-based subsidiaries to the same standards as domestic companies is difficult, if not impossible: Ford of Germany, Opel (owned by GM), Simca (owned by Chrysler), and whatever others there were under the laws of the countries they were in, not US laws, and can't be held entirely responsible for their actions during wartime. On the other hand, if a company like IBM supplied equipment to Germany during the war (and there is some evidence that they did so), that is an entirely different matter.

This is also a sidetrack to the current discussion, and to the discussion of military hardware being built by second sources. Most military hardware is developed at public expense, and the rights to the design are owned by the organization paying for the development_, i.e._the US government by means of money from taxpayers and the creditors of the US government.


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## swampyankee (Jan 8, 2018)

Zipper730 said:


> Firstly, nuclear bombs are a weapon only to be used in total war. Wars have various sizes from minor conflicts to world-scale conflicts.
> 
> Carriers come into their own in wars that are small/moderate scale where nuclear bombs are not really all that practical: Regardless, the carriers were able to launch aircraft (P2V's and AJ's) off their decks which could carry nuclear bombs (the AJ could be recovered) in a total-war setting, and could carry large numbers of aircraft with conventional ordinance off the coast of an enemy nation. At the start of a war, the carriers are useful because most bombers required some form of escort unless they operated at night, and nearby air-bases might very well be under another nations control and require some negotiation for agreed upon terms of use (a carrier presents no such restriction as long as it stays in international waters).
> 
> ...



*Mankind* was already at the Pacific Ocean; Manifest Destiny was specifically for white Americans, a group that, at the time, barely included the Irish.


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## Zipper730 (Jan 10, 2018)

Whoops, I meant America...


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## tyrodtom (Jan 10, 2018)

America was already sea to shining sea before manifest destiny too.
For some reason citizens of the USA thinks the term Americans apply only to them .


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## XBe02Drvr (Jan 10, 2018)

tyrodtom said:


> America was already sea to shining sea before manifest destiny too.
> For some reason citizens of the USA thinks the term Americans apply only to them .


WHITE citizens of the USA, that is! Native American citizens, African American citizens, Asian American citizens of the US and Latin American citizens of the entire western hemisphere know better.
Cheers,
Wes

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## GregP (Jan 11, 2018)

"Americans" applies to anyone from North or South America, and perhaps residents of "Little America" in the Anarctic. It's really the REST of the world that calls U.S. citizens "Americans," and the press. Almost nobody else I know makes that mistake.


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## Zipper730 (Jan 11, 2018)

tyrodtom said:


> America was already sea to shining sea before manifest destiny too.


If you mean the continent, of course: If you mean the United States, then no.



XBe02Drvr said:


> WHITE citizens of the USA, that is! Native American citizens, African American citizens, Asian American citizens of the US and Latin American citizens of the entire western hemisphere know better.


Sadly, all too true. At least I don't have any problems with people who are Native Americans, African Americans, Asian Americans and Latin Americans. Admittedly I don't currently have any as friends, but I've never selected friends on the merit of their ethnicity.



GregP said:


> "Americans" applies to anyone from North or South America, and perhaps residents of "Little America" in the Anarctic. It's really the REST of the world that calls U.S. citizens "Americans," and the press. Almost nobody else I know makes that mistake.


I'm not really sure how citizens of the US became known as Americans... I guess United Statesian doesn't sound as good.

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## XBe02Drvr (Jan 11, 2018)

Zipper730 said:


> I'm not really sure how citizens of the US became known as Americans... I guess United Statesian doesn't s


How about "Yankees"? A lot of people around the world use the term to refer to us. Not popular with Red Sox fans or our misguided friends in Dixie.
What is a Yankee? If you're in Eurasia/Africa, it's someone from the Americas. If you're in South/Central America, it's somebody from North America. If you're in Canada or Mexico it's someone from the US. In the US it's somebody from the North. If you're in the North, it's New England. In New England, the word "real" gets attached and it's someone from Vermont. In Vermont it's the three counties that constitute "The Northeast Kingdom". Ayup.
Cheers,
Wes

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## fubar57 (Jan 11, 2018)

Topic........................................


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## Zipper730 (Jan 14, 2018)

Let's get back onto topic: The F7F



wuzak said:


> Regarding the engines, the project timing probably didn't allow consideration of the R-2800.
> 
> According to this, the project started in 1939. At which point the R-2800 was still relatively early in development, while the R-2600 was in production.
> 
> The XF6F also used an R-2600.


Okay, I did some research and the F4U used an R-2800 and it flew in 1940...


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## Zipper730 (Jan 14, 2018)

I was looking into the use of the 37mm M4 versus the M3 (anti-tank) and found the biggest difference: The M3's barrel was 154.3" versus the M4's 89.5"; Other differences would include the ammo weight: The M3's total weight was 1050g, versus the M4's 900g; the mass of the projectile itself was 750g for the M3, and 608g for the M4. 

A longer barrel helps accuracy because of rifling, and the effect of spinning the bullet up to speed: What effect does it have on muzzle velocity and explosive gas force?


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## tomo pauk (Jan 14, 2018)

The cartridge for the M4 sported less propellant charge than for the M3 gun. More propellant = needs longer barrel.


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## Zipper730 (Jan 14, 2018)

tomo pauk said:


> The cartridge for the M4 sported less propellant charge than for the M3 gun. More propellant = needs longer barrel.


Would the gun not spin up to speed without one, or would it somehow blow up the barrel?


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## tomo pauk (Jan 14, 2018)

I don't think that blowing up a barrel was that easy with US/Western standards of the day. Barrel lenth, thickness/strength and rifling is directly depnedant on projectile size and weight, as well as amount and type of propellant used. No point in having a gun barrel being to long if the amount of propellant is modest.


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## wuzak (Jan 14, 2018)

Zipper730 said:


> Would the gun not spin up to speed without one, or would it somehow blow up the barrel?



I think he is saying that the propellant needs to burn out before it exits the barrel.

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## Zipper730 (Jan 14, 2018)

wuzak said:


> I think he is saying that the propellant needs to burn out before it exits the barrel.


So, the M3 needed the full length?


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## pinehilljoe (Jan 14, 2018)

GregP said:


> You are asking questions that I doubt younger people can answer. There are a few in here who stubbornly think the U.S.A. should have bought foreign weapons, particularly the DH Mosquito.
> 
> ....
> The R-2800 first flew in 1940, but the "B" series is what started them down the right path. That said, actual development times for the Grumman Cats wasn't bad at all.



License built or purchased Mosquito's would have helped the Night Fighter Squadrons.


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## Zipper730 (Jan 14, 2018)

pinehilljoe said:


> License built or purchased Mosquito's would have helped the Night Fighter Squadrons.


For the USAAF? Yes, for the USN, it'd be okay unless you lost an engine.


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## pbehn (Jan 14, 2018)

pinehilljoe said:


> License built or purchased Mosquito's would have helped the Night Fighter Squadrons.


License built would have taken too long and purchased meant choosing the USA night fighter needs over other priorities, at the time almost everyone wanted more mosquitos.


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## Shortround6 (Jan 14, 2018)

Zipper730 said:


> So, the M3 needed the full length?


Spin has sod all to do with anything in this discussion. Use the appropriate rate of twist in the rifling and you can spin any projectile at the right speed to stabilize. Lower velocity just calls for a quicker twist in the rifling. 





The AA/AT/tank gun round used a LOT more propellant than the 37mm aircraft gun. firing it out of short barrel would have resulted in a LOT of muzzle flash and a considerably lower muzzle velocity compared to the full length barrel, even if better than the short round.

Please look up the actual differences and not focus on quicky comparisons like barrel length. You can get .357 magnum revolvers with barrels from 2-2 1/2 inches to 8 inches. Huge change in velocity. You can also fire .38 specials in a long barreled revolver and sometimes equal a .357 from a short barrel. 

Most (all?) cannon were much more restricted in the ammo they fired than small arms. They didn't want to make up new firing tables/charts for different velocities/projectiles.

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## Shortround6 (Jan 14, 2018)

Zipper730 said:


> For the USAAF? Yes, for the USN, it'd be okay unless you lost an engine.


Mosquitos could stay in the air on one engine. 
many large twin bombers (especially British ones) could *not*, but the Mosquito was not one of them.

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## wuzak (Jan 14, 2018)

Shortround6 said:


> Mosquitos could stay in the air on one engine.
> many large twin bombers (especially British ones) could *not*, but the Mosquito was not one of them.



And, if lightly loaded, could do aerobatics on one engine.

Geoffrey de Havilland Jnr famously did so when demonstrating the prototype.


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## XBe02Drvr (Jan 15, 2018)

Shortround6 said:


> Mosquitos could stay in the air on one engine.
> many large twin bombers (especially British ones) could *not*, but the Mosquito was not one of them.


I challenge you to get your single engine Mosquito onto a pitching carrier deck at night and walk away from it! Zipper's right this time.
Cheers,
Wes


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## XBe02Drvr (Jan 15, 2018)

Shortround6 said:


> The AA/AT/tank gun round used a LOT more propellant than the 37mm aircraft gun. firing it out of short barrel would have resulted in a LOT of muzzle flash and a considerably lower muzzle velocity compared to the full length barrel, even if better than the short round.




Ye gads! Can you imagine stuffing an M3 and what, maybe 12-15 M63 rounds into a fighter plane? The breech would be practically in the pilot's lap, and where would you stuff the ammo? But you might wind up with a trajectory that would nearly match your .50s.
Cheers
Wes


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## Shortround6 (Jan 15, 2018)

XBe02Drvr said:


> I challenge you to get your single engine Mosquito onto a pitching carrier deck at night and walk away from it! Zipper's right this time.
> Cheers,
> Wes


USN nightfighter squadrons used single engine planes during WW II. Loose the engine and you don't even make it back to the carrier to ditch alongside (or by destroyer.)
Any twins used (Marines used some Venturas) as night fighters were land based.


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## Shortround6 (Jan 15, 2018)

There was an enlarged 37mm aircraft gun using the big 37mm ammo. Most sources say it was used only on PT boats.





While the barrel was only about 15in longer it weighed twice as much and the Breech mechanism also weighed almost double what the small 37 did. (405lbs for the complete gun). It may have been planned for the P-63 but if any were fitted it was for testing only.


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## tomo pauk (Jan 15, 2018)

XBe02Drvr said:


> Ye gads! Can you imagine stuffing an M3 and what, maybe 12-15 M63 rounds into a fighter plane? The breech would be practically in the pilot's lap, and where would you stuff the ammo? But you might wind up with a trajectory that would nearly match your .50s.
> Cheers
> Wes



Soviets did it.
Their NS-37 cannon fired ammo that was more powerful than the ammo the US anti-tank guns. Used both against aerial and ground targets, rate of fire 250 rds/min (almost twice the M4 from P-39s was capable for). The LaGG-3-37 and Yak-9K used the cannon.
NS-37 37mm cannon
American M9 cannons was of similar properties, but I don't think that it was ever used in combat.


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## tyrodtom (Jan 15, 2018)

The magazine certainly looks similar ( maybe enlarged) to the 37 mm magazine used on the P-39.


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## *SkyChimp* (Jan 15, 2018)

> I believe the M-16 rifle was one of the few modern weapons to be built in multiple factories (although the M-14 was also),
> strange as politics and government contracts are the Government (army) wanted more than one source during the vietnam war, which is understandable.
> However Colt had to turn over not only blueprints of the rifle but information on tools, jigs, manufacturing procedures/techniques and so on. The two other companies that built the M-16 at the time (everybody with lathe in the garage seems to be building them now) both charged more per rifle than Colt. One company charged almost double what Colt was getting per rifle in contract at the same time.
> The strange part (and politics) comes in when at least one senator wanted to investigate Colt for excessive profits but not the other companies.




At the risk of bringing this topic further off topic, the other companies probably would have to charge more for copies of the M16 than Colt. Colt owns the Technical Data Package (TDP) for both the M16 and M4 carbine. The US Govt may share the TDP with other producers, but those producers must pay Colt a royalty for every gun they manufacture using Colt's TDP. Presently, Colt doesn't have a contract with the US Govt to produce the rifle or carbine. I believe the present contract is with FN in South Carolina. Yet, Colt makes money off that contract in the form of royalties.


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## XBe02Drvr (Jan 15, 2018)

Shortround6 said:


> Loose the engine and you don't even make it back to the carrier to ditch alongside (or by destroyer.)


Statistically the same engine installed in a twin has nearly twice the inflight failure rate as it does in single engine applications. Don't ask me why. Carrier aviators of the time all took their chances with a single engine.
Cheers,
Wes


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## wuzak (Jan 16, 2018)

XBe02Drvr said:


> Statistically the same engine installed in a twin has nearly twice the inflight failure rate as it does in single engine applications. Don't ask me why. Carrier aviators of the time all took their chances with a single engine.
> Cheers,
> Wes



Wasn't that more to do with the size of the aircraft and the size of the aircraft carrier?


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## XBe02Drvr (Jan 16, 2018)

wuzak said:


> Wasn't that more to do with the size of the aircraft and the size of the aircraft carrier?


Well, that's definitely a concern, but in the case of the Mossie, it's a tail dragger, not especially known for it's low speed handling and even worse with assymetric thrust. Its ability to execute a waveoff on one engine in dirty configuration from carrier approach speeds would have been dubious at best. The alternate scenarios are: 1, a crash on deck (heavy, fast, combustible, UGLY SCENE), or 2, a VMC roll into the drink alongside, likely hitting the water nose down inverted and rolling. There's a reason why pretty much all carrier based large twins have historically been trike gear machines, operated from angle decks, and attempted engine out landings only in the most dire emergencies. The protocol in case of an engine failure is bingo ashore.
Cheers,
Wes

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## BiffF15 (Jan 16, 2018)

A nice long piece of pavement is so nice... And a hotel with a bar... And per diem... And AF guys are such p---ies...


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## XBe02Drvr (Jan 16, 2018)

BiffF15 said:


> A nice long piece of pavement is so nice... And a hotel with a bar... And per diem... And AF guys are such p---ies...


We had the East Coast F4J RAG squadron ACM training detachment on base, while nearby McDill AFB had the F4E Replacement Training Squadron. They used to visit us from time to time for "short field practice" on our 8500 foot runways. They would always send a truckload of mechanics and wheel, tire and brake assemblies to wait in the hot brake area for every landing.
Their landings were entertaining to watch, often floating a third of the way down the runway before greasing on at about Navy/Marine approach speed. We always had a crew out there to do quick resets of the overrun arrestor gear. It's hard to imagine that hunk of iron as a floater, but the AF managed to do it.
Once on the ground, they clustered together in their immaculate flight suits under the supervision of their training cadre and stared about them like Parisian sophisticates suddenly transported to a peasant village in India. They refused all offers of hospitality or sustenance as if they feared contamination or infestation, got back in their jets and went home. A true intercultural exchange!
Cheers,
Wes

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## pbehn (Jan 16, 2018)

Even as a Brit I have heard of the perils of landing at a rival force's airfield by misfortune or worse, by accident, aircraft covered in graffiti and the butt of everyones jokes.


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## XBe02Drvr (Jan 16, 2018)

pbehn said:


> Even as a Brit I have heard of the perils of landing at a rival force's airfield by misfortune or worse, by accident, aircraft covered in graffiti and the butt of everyones jokes.


This was no accident or misfortune, but a deliberate training exercise. And forget graffiti, along with the mechanics came Air Police who quickly established a perimeter around the aircraft and crews while they conducted their debrief. Woe betide the poor sailor or officer who might try to approach. "Untermenschen need not apply!"
Cheers,
Wes


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## soulezoo (Jan 17, 2018)

BiffF15 said:


> A nice long piece of pavement is so nice... And a hotel with a bar... And per diem... And AF guys are such p---ies...


Hey now! I didn't complain! And besides, it's expensive down under!

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## GregP (Jan 17, 2018)

The Mossie was one of the worst twins on one engine ever conceived. Vmc is 175 knots! Doesn't mean it was bad; it means it needed two engines or else land straight ahead when an engine fails if you are slower than Vmc.

It had a lot of really good qualities, but single-engine operations weren't one of them.


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## XBe02Drvr (Jan 18, 2018)

GregP said:


> The Mossie was one of the worst twins on one engine ever conceived. Vmc is 175 knots! Doesn't mean it was bad; it means it needed two engines or else land straight ahead when an engine fails if you are slower than Vmc.
> 
> It had a lot of really good qualities, but single-engine operations weren't one of them.


The function of the second engine is to deliver you to the scene of the accident.
Cheers,
Wes

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## pbehn (Jan 18, 2018)

XBe02Drvr said:


> The function of the second engine is to deliver you to the scene of the accident.
> Cheers,
> Wes


If it got me close enough to the carrier to parachute out I wouldn't mind.

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## Zipper730 (Jul 15, 2018)

*Regarding the F7F*

I'm curious about the R-2600/R-2800 thing: If the R-2800 first was available in 1940 what was the issue with procuring them? The USN was okay with buying them for the XF4U and the program started back in 1938 right? Were they buying the R-2800 back then or were they to use a different engine?

*Regarding the 37mm cannon*



Shortround6 said:


> There was an enlarged 37mm aircraft gun using the big 37mm ammo.


If I recall it was the M9


> It may have been planned for the P-63 but if any were fitted it was for testing only.


It was proposed for the XA-41 as well interestingly. Though it was quite heavy, it had a faster muzzle velocity and delivered a heavier projectile which would be useful.



tomo pauk said:


> Their NS-37 cannon fired ammo that was more powerful than the ammo the US anti-tank guns.


How did they get it down to such a light weight. These figures indicate around 330 pounds vs 405


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## Shortround6 (Jul 15, 2018)

Zipper730, a lot of this stuff is easily available.

go to http://www.enginehistory.org/

click on reference and scroll down to 

Problems of Accelerating Aircraft Production During World War II 

at the end there are production totals by factory and by models/types of engines similar engines get lumped together. 
Like in 1940 P & W built 17 R-2800 production engines. In 1941 they built 1471 A series engines. 
Please note P& W stopped production of the A series in Jan of 1941 and shifted to the B series. 

It takes time to tool up and get in production. 

Russian guns were built to different standards. They expected to junk the gun and replace it (assuming the gun lasted long enough in combat) with many fewer rounds fired than the US or Britain did.


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## Zipper730 (Jul 15, 2018)

Shortround6 said:


> It takes time to tool up and get in production


Yes, I'm aware of that: What I was trying to get to was basically this

The XF4U-1 was a new design in 1940, it's origins were back in 1938
The R-2800 was first available in 1939, and first reached the 10,000 levels in 1942
The F4U-1 was first available operationally in 1942-1943
The F7F didn't first fly until late 1943
Everything took time, I get that but my point is that it didn't stop Vought with going with the R-2800. It seems it would be better to claim that the R-2600 might have been better trusted as a design as it had a track record where the R-2800 had none.


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## Shortround6 (Jul 15, 2018)

The XF4U first flew with some sort of a bastard A series engine. It may or may not have had a working two stage supercharger in the first few flights. I believe the XF-4U prototype flew with at least 3 different engines if not 4.
Vought and P & W were both part of United Aircraft corporation and Vought _may_ have had better knowledge of the status of the R-2800 compared to Grumman.

I would note the R-2800 didn't _fly _in any form or in any airframe until July of 1939 and that was a modified Vultee attack bomber.
Please look at the production numbers again. Of the 17 R-2800s built in >1941< 8 of them were in Dec. An engine sitting in crate on the loading dock in Harford Ct doesn't do any good to an Aircraft factory over a hundred miles away and needing two if not 3 railroads to get there. (or a ferry)

A lot of manufacturers placed a lot of hope/trust in P&W in 1940-41. Things could have gone very wrong. Ford was spending over 14 million dollars of Govt money to build a factory for the R-2800 when fewer than a dozen had been built or run.

edit> that should be 17 engines in 1940 not 1941. Ford Broke ground on the new factory in Sept of 1940.

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## Zipper730 (Jul 17, 2018)

Didn't the F6F start with a turbocharged R-2600?


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## GregP (Jul 17, 2018)

That is too easy to answer, Zipper. You KNOW that answer yourself.


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## Zipper730 (Jul 18, 2018)

Greg,

No: I know the R-2600 was installed in the prototype. I'm pretty sure there was a turbocharger as well and I vaguely remember seeing figures that indicated 400+ mph.

I'm guessing it either didn't work well enough because they didn't pursue it.


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