VI: no Allison V-1710
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- #22
That 1400 HP figure is indeed for take off (1500 for the last version), so it will need turbo to help out with altitude. The R-2800 didn't power an USAAF fighter in combat before 1943.
Shortround6
Major General
Which latest version? it was not built according to : https://www.enginehistory.org/Piston/P&W/R-2180/R-2180Index.pdf
While the R-2800 didn't power a fighter(army or Navy) in combat until 1943 it certainly powered B-26 bombers in combat starting in June of 1942.
Since the R-2180 used the same size cylinders as the R-2800 for a quick and dirty estimate of power use the R-2800 figures and multiply by 7/9ths. (0.777).
This also points out the production problem, until more factories are built R-2180s can only be built at the cost of R-2800s not built.
This assumes you have an equal supercharger set up and equal cooling, it also assumes equal RPM which, for the early engines didn't happen. The unbuilt 1500hp version did use the same RPM as the 1850hp R-2800s.
The cancelation of the R-2180 had very little to do with government funding and a lot to do with P & W wishing to devote more resources to the R-2800 which had been in development for several years when the R-2180 was dropped. Given enough orders P & W might well have continued with it but they knew it wasn't large enough to compete with Wright's R-2600 and P & W wanted an engine that could beat the R-2600, not play junior partner to it.
P & W had dropped the R-1535 even though the Navy liked it because the Navy was the only customer and P & W knew the engine market was shifting to bigger engines. So this was not the first time that P & W vision of the future was better than the Military's.
edit, so just for laughs lets stick a two speed R-2180 in the nose of a Curtiss Hawk, Using 7/9ths the power of an Early B-26 engine you have a whopping 1166hp at 1400ft from a 1750lb engine that is 51.6 in in diameter. Better than a regular P-36 but not so good compared to a P-40. Now figure the drag of a 1939-41 cowling and not one from 1942/43.
P-39 turns into this
While the R-2800 didn't power a fighter(army or Navy) in combat until 1943 it certainly powered B-26 bombers in combat starting in June of 1942.
Since the R-2180 used the same size cylinders as the R-2800 for a quick and dirty estimate of power use the R-2800 figures and multiply by 7/9ths. (0.777).
This also points out the production problem, until more factories are built R-2180s can only be built at the cost of R-2800s not built.
This assumes you have an equal supercharger set up and equal cooling, it also assumes equal RPM which, for the early engines didn't happen. The unbuilt 1500hp version did use the same RPM as the 1850hp R-2800s.
The cancelation of the R-2180 had very little to do with government funding and a lot to do with P & W wishing to devote more resources to the R-2800 which had been in development for several years when the R-2180 was dropped. Given enough orders P & W might well have continued with it but they knew it wasn't large enough to compete with Wright's R-2600 and P & W wanted an engine that could beat the R-2600, not play junior partner to it.
P & W had dropped the R-1535 even though the Navy liked it because the Navy was the only customer and P & W knew the engine market was shifting to bigger engines. So this was not the first time that P & W vision of the future was better than the Military's.
edit, so just for laughs lets stick a two speed R-2180 in the nose of a Curtiss Hawk, Using 7/9ths the power of an Early B-26 engine you have a whopping 1166hp at 1400ft from a 1750lb engine that is 51.6 in in diameter. Better than a regular P-36 but not so good compared to a P-40. Now figure the drag of a 1939-41 cowling and not one from 1942/43.
P-39 turns into this
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swampyankee
Chief Master Sergeant
- 3,994
- Jun 25, 2013
This particular R-2180 -- there were two -- was from a different developmental strain than the R-2800. The later R-2180 had R-2800 and R-4360 DNA. Like Curtiss-Wright, many Pratt & Whitney engines had common bore and stroke.
Shortround6
Major General
Perhaps?
The R-2180E (post war) certainly had the DNA (shared parts) between the R-2800 C and the R-4360. But since the R-2800 C shared only the bore and stoke and few odd parts with the R-2800 B one is allowed to wonder if the early R-2180 and the R-2800 A shared any parts or DNA
One thing is for certain, the R-2180 Twin Hornet didn't share any parts with the R-1690 Hornet despite the name.
- Thread starter
- #26
We will need it to be built
Without the V-1710 in the picture, the USA will need to invest that money in production facilities of radial engines instead.
Benefit of the R-2180 is that it is smaller than R-2600 (same as with V-1710 vs. R-2600), so it can be installed in places the R-2600 will not easily fit. Let alone the R-2800.
It is 1166 HP at 14000 ft? That's 25% more than what best P-36 had at that altitude. Granted, the take-off weight will jump by ~400 lbs (7-8%).
P-39 turns into this
Rumor has it that American radials were a bit better than Italian
Reluctant Poster
Tech Sergeant
- 1,611
- Dec 6, 2006
The liberty and 1A2500 were separate cylinder engines which were obsolete long before WWII. There are no examples of successful separate cylinder aero engines in WWII. The 1A2500 was considered to be inferior to the Curtiss D12. The D 12 successor the Conqueror would have been a better bet.
The IV-2220 first ran in December 1942. In no way could it have been ready for WWII. The V-770 was too small to be of any use in combat aircraft. The less said about the I-1430 the better.
The much simpler tank version of the Ford engine entered service trials in May 1942 with many problems
M4 Sherman
It wasn't cleared for service until June 1943. It is difficult to believe the more complex aero version would have a shorter gestation period.
i find it difficult to believe that its cast crankshaft would have withstood the rigors of 1700 hp in aero service. When Ford introduced their massive Super Duty gasoline V8s in the 50s they used forged cranks. Their big high performance V8s of the 60s also used forged cranks
Shortround6
Major General
We run into a funding/timing problem here, General Motors/Allison funded the construction of the Allison production facility in 1939 after getting the order for the P-40 engines In April/May of 1939. How much the plant was expanded later I don't know, however GM did support Allison with not only engineers but with extensive subcontracting in later years, Cadillac for instance making crankshafts and connecting rods.
The US government didn't start funding engine factories until the summer of 1940. Ford got 14 million just to build the factory that built R-2800s in Sept of 1940, payments for the engines was separate. P & W was quadrupling the size of their Harford factory in 1938-40 due to the French and British orders. A major help but the US needed many times the factory capacity.
US engine production roughly tripled every year during the war (until 1944 at which point the end was in sight). This is what makes changing some of the historical production plans rather questionable. The US government wasn't going to fund factory construction until the summer of 1940 so the choice of engines to made by the engine makers wasn't in the hands of one person or agency. Different companies made decisions on which engines to build based on what they thought the future markets would buy. Wright flushed about 6 million dollars down the toilet with the R-2160 Tornado program and wasted thousands (if not tens of thousands) of engineering hours that could have been better spent on the R-2600 and R-3350 in retrospect.
If Allison is removed from the picture in 1938/39 (or before) you have to pick an engine and start building plant/s for it in 1939 or you have a shortfall of thousands of engines in 1941-42. when the factories started in late 1940 begin to really come on line. However, pick the wrong engine and it is going to take longer to transition to the engines used in 1943 and after.
Wright 1600hp R-2600s and 1700hp R-2600s were never made in the same factory (except for a few experimentals), factory tooled up for the 1600 version needs a thorough retooling to make the 1900hp version used in the late war SB2Cs and TBMs (in fact all the 1900hp engines were built in the plant that made the 1700hp version)
Actually the R-2180 is less than 1 in smaller in diameter than the R-2800 in most versions. Length depends on supercharger and accessories on the back. It is lighter than the R-2600 and R-2800.
Take-off weight will jump by 600 lbs or more, you need a bigger propeller and a larger oil cooler for starters. bigger engine mounts etc.
Very few P-36s (or Hawk 75s) got 2 speed superchargers. when P & W did get around to two speed superchargers (they offered the two stage supercharger before the 2 speed
the R-1830 was good for 1050hp military at 13,100ft. True but if the Allison dies early both the P-38 and P-39 die along with it in addition to the P-40.
and no a P-38 with twin turbo R-1830s isn't going to come close, not until the drag problem is sorted out and that is going to take until 1942 just for the prototype forms, production in large numbers won't show up until 1943.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
The list of engines I posted (including Packard's L-12 development timeline) was to illustrate that Allison wasn't the only "inline" engine producer out there.
Now assuming that Tomo intended that GM's Allison division went into decline at some point in the 30's (perhaps due to the depression?), then the other engine manugacturers would have certainly stepped up their development in the vacuum left by Allison. Especially since the Army and the USN were a good source of money in a cash-strapped economy.
I would speculate that Packard would have taken the lead and their marine version engines (3M, 4M and 5M) were quite impressive.
Now assuming that Tomo intended that GM's Allison division went into decline at some point in the 30's (perhaps due to the depression?), then the other engine manugacturers would have certainly stepped up their development in the vacuum left by Allison. Especially since the Army and the USN were a good source of money in a cash-strapped economy.
I would speculate that Packard would have taken the lead and their marine version engines (3M, 4M and 5M) were quite impressive.
Shortround6
Major General
Packards chief aircraft engine designer died in a plane crash in 1930.
Packard also got out of the aircraft engine business (or shifted to radial diesels) after the US navy said they would no longer buy liquid (water) cooled engines.
The PT boat engines were developments of the aircraft engines.
However the design was somewhat out of date.
Please note that 1200-1350hp at sea level was no great trick from a 2500 cu in engine. the Trick is making 1200-1350hp at 12,000 to 16,000ft in 1940-41 and making 1200-1350hp at over 20,000ft in in 1942.
Packard also got out of the aircraft engine business (or shifted to radial diesels) after the US navy said they would no longer buy liquid (water) cooled engines.
The PT boat engines were developments of the aircraft engines.
However the design was somewhat out of date.
Please note that 1200-1350hp at sea level was no great trick from a 2500 cu in engine. the Trick is making 1200-1350hp at 12,000 to 16,000ft in 1940-41 and making 1200-1350hp at over 20,000ft in in 1942.
wuzak
Captain
One of Allison's early contracts was building servicing the Liberty V-1650 post WW1, and then converting some to inverted air-cooled V-12s (Allison VG-1410).
As for producing inline engines, Packard built:
3 x X-2775 between 1927 and 1935
258 x 1A-2500 for aircraft. Marine engines didn't even get started until 1941?
29 x 1A-1500s built from 1924
And a prototype L8.
In contrast, Rolls-Royce built
327 x Condor from 1918 to 1930, including one which was converted to compression ignition and one that ran a turbo
4750 x Kestrel from 1926 to ~1940
100 x Buzzard from 1928 to ~ 1930
19 x 'R' from 1929 to 1933?
20 x Goshawk (steam cooled Kestrel) from 1932 to 1935
538 x Vultures from 1937 to 1941
301 x Peregrine from 1938 to 1941
Plus however many Merlins were built between its inception and WW2.
You may point to the Liberty L12, Over 20,000 of them were built by several manufacturers, including Packard, Ford and Buick. Over 13,500 L12s were built before the end of WW1, and all but a few hundred were built before the end of 1919.
Packard weren't so much producing engines in the interwar period, but keeping their toe in the water.
This might seem like a naive and a bit provocative as a question, but would not having the V-1710 (or other water cooled inline engine) really changed US aircraft development? The major aircraft that are associated with this engine (P-40,P-39/63,P-38) all seem to have had limited development during the course of the war. The one major change to the P-40 was to re-engine the airframe with the merlin, the P-39/63 found its greatest success through lend-lease and not US forces, and the P-38 was saved by a switch in theater operations where the engine shortcomings were over come. Not to say anything about the constant effort to re-engine it with the Merlin as well. I haven't included the Mustang/Apache in this because its really a plane designed to RAF standards and still required a new engine. Otherwise, air cooled radial engines are the dominant power plant in aircraft design to US forces design criteria. I wonder, which aircraft would have evolved to fill gaps eft by the P-40/P-39/P-38 if they had not been developed around the V-1710. I posted earlier that designs like Grumman's F5F/P-50 might have filled the niche vacated by the P-38. That's my two cents.
swampyankee
Chief Master Sergeant
- 3,994
- Jun 25, 2013
In defense of Allison, the P-38's problems in the European theatre were the result of significant problems in the aircraft's detail design, including the engine induction system, cockpit heating, aileron authority, and Mach tuck. None of these were the responsibility of Allison. There may have been one problem that was actually Allison's authority, but the listed problems would be just as bad with just about any V-12 engine, e.g., the Merlin. They may not have occurred on some alternate-history radial-engined P-38 equivalent, but the P-38's problems originated in Lockheed's design office, not Indianapolis.
wuzak
Captain
No V-1710 means no P-40.
No P-40 means no P-51.
No P-51 means no P-51B, C, D, k or H. Means more bombers get killed, more 8th AF crew die and the daylight bombing campaign is far less effective, It may even end up being absorbed into night bombing with the RAF.
Shortround6
Major General
Well, this is revisionism. . The P-38 was used in the Aleutian Islands first, hardly a tropical climate even if not as bad as some might think. A few went to England in the fall of 1942 but use was extremely limited, too limited to uncover an engine shortcomings before they were re-assigned to the North Africa Invasion, P-38s would not return to NW Europe for around a year.
time line goes like this.
Aug 28th, 42. The First fighter group in England is ready for combat.
Aug 29th, 42. Two P-38s of the 94th squadron, First fighter group attempt to intercept German aircraft over England, no cntact.
Sept 2, 42. The First FG flies 1st mission from England, 32 aircraft on a fighter sweep over France. 340 sorties made in the next few days.
Sept 14th, 42 the four fighter groups if the 8th AIr Force are transferred to the 12th AIr Force and allotted for shipment to North Africa for operation Torch.
Sept 16th, 42. the P-38 groups in England are fully operational.
Oct 15th, P-38s fly their first B-17 escort mission from England.
Oct 31st, 42 The P-38Fs in England are withdrawn from combat status to be ready for torch.
Nov 14, 42 the First and 14th Fgs with P-38Fs transfer from England to North Africa, one 14th group squadron stays in Iceland.
Nov 16th, 42, the 14th fighter group is operational in North Africa.
It is not until Oct 15th 1943 that a fighter group with P-38s will be operational in England for use as bomber escorts. So where does the "switch in theater operations" that saves the P-38 come in? P-38s were on Guadalcanal (small numbers) in late Aug of 1942.
BTW the constant effort to re-engine it with the Merlin was all paper engineering studies, no metal was ever cut on any of these proposals let alone a plane completed.
considering they actually built the XP-49
with Continental XI-1430 engines one has to wonder just how serious those Merlin proposals were.
Not unless you can figure out a way for those barn door radials to not create drag.
1st major change was when they yanked the radial R-1830 and stuck in the Allison. The Allison was the 4th or 5th engine change on the Hawk airframe (or 6th depending on when the first R-1820 went into it)
Shortround6
Major General
wuzak
Captain
North American builds P-36 beater with laminar flow wing and R-1830 engine
And then Bristol realise it would be better with a Hercules and then re-engineer it with the best model, which enable the P-36 beater to fly half as much again as a Spitfire V!
Thanks for your reply, Wuzak. I'm not so sure the no P-40 means no P-51, although if there is no V-1710 to power the airframe there might not be the transition to the Merlin. I've always thought the P-51 was designed in pretty much the perfect set of circumstances. It wasn't contracted by the USAAF and didn't have that oversight during initial design. The designer, Smued, had filed away a kind of outline of best ideas for a future fighter that he was able to draw upon and the lack of oversight let him put as many advances in the design as possible. Given the RAF's preference (tradition?) for inline power plants who's to say the Merlin wouldn't have been incorporated from the start. Just my thoughts.
Greetings Shortround,
Thanks for your reply and for calling me out. (meant sincerely without irony or any other such nonsense) As I stated starting the thread a bit naive and provocative. I certainly agree that the P-38 had a much more significant and expanded role than my post indicated and I was probably being "revisionist" to spur the dialogue. My understanding (which can certainly be way off base) was that Lockheed had explored getting Merlins to test on the P-38 airframe, but were turned down tiring shortage of available engines and this never went anywhere. My impression of the P-38 (and feel free to correct this) is that it was best in warmer environments where there were less issues with the turbo icing and seizing hence my statement that it needed to be in a different theater of operations.
Thanks Again!
