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Why?
Work it out. Merlin. 45s are available by the time the R-2800-5 is. British don't have time or engineering capacity to even install Merlin XX.
Was that really a problem of time or capacity? I thought that was simply a case of (imo botched) priorities, the engines going to the Hurricane II and other projects instead.
According to some the Merlin XX was 4in longer and wouldn't fit easily.
The Hurricane needed the XX. To stay in the game at all.
Spitfire got the MK XII at about the same time. Merlin 45 is pretty much a XII with a XX supercharger without the 2 speed drive. There is only so much engineering time available (that includes draftsmen making the drawings).
Wasting it trying to put a low altitude radial on the Spitfire sure seems like a waste of resources.o
Why not? Merlin 45 was inadequate to make Spitfire competitive vs. the 109F-4 and even the troublesome Fw-190s (=prior late 1942).
The 1-stage R-2800 turns Spitfire into a 1850 HP machine in 1941, 2000 HP machine in 1942. By the time Germans sort out the 801D, the 2 stage Merlin can get into the fray; the radial remaining in production service.
As for the British/Supermarine/RR having no time or engineering capacity to install the XX into Spitfire, that's not the serious statement, right?
Agreed. The power egg from Beaufighter, trialed at that Miles fighter, seem like a neat thing to be attached to the Spit. It also ditches the under wing radiator, not a bright spot on the Spit.
Too bad that, by that decision, Spitfire V became 2nd, and then, fast, only the 3rd best fighter in ETO.
Yet it was plenty of engineering time to fiddle with Sabre/Typhoon saga? Granted, not the same companies, but the costumer was the same. The hard pressed Soviets managed to find the time to re-engine the Lagg-3, Italians can do it (3 companies at short time), but the British somehow can't pull it?
The sentence from above still stands. Making a handful of the Spitfire Mk XIIs seem to imply that there was need to the fighter that can do well under 20000 ft.
I am not sure this argument comes through in application. The Fw-190A with the 801D engine was capable of doing 330-340 mph at SL with 1700-1800 hp. The contemporary F4U-1, was capable to doing 350 mph at SL with 2000 hp. The F4U is about 2000 lb heavier than the Fw-190 and has 50% more wing area. It seems the the more efficient cowling design, if it existed, helped little to overall aircraft efficiency.The question here is were on this curve or path of cowling development would a 1940/41 R-2800 cowling fall? better than the P-36 but not as good as the Fw 190 or P&W experimental cowling ( or later F8F and Fury cowlings)? add the 1.7% to a few percent for not as good a basic design of cowl ( XP-42 went through how many variations and the P-66 itself went through a few) and add in the cooling drag. You are going to need more cubic feet of air going through the cowling to cool an 1850-2000hp engine than a 1600-1700hp one. This is were the big changes in drag for radial engines came from. They had figured out the external shape pretty early. It is the internal airflow/baffling/and exit that changed dramatically. Cowlings like the Fw 190 and F6F and later used the exhaust for two purposes, one was exhaust thrust and the other was to use a flow of air created by the exhaust to suck air through the cowling. The F4U-1 just dumped it's exhaust out the bottom through two pipes.
Granted cowlings can be "tweaked" as a design progresses even through (or especial through) the prototype stages but I have a hard time seeing service cowlings as good as the Fw's in Dec of 1941 or even the Spring of 1942.
Why not? Merlin 45 was inadequate to make Spitfire competitive vs. the 109F-4 and even the troublesome Fw-190s (=prior late 1942). The 1-stage R-2800 turns Spitfire into a 1850 HP machine in 1941, 2000 HP machine in 1942. By the time Germans sort out the 801D, the 2 stage Merlin can get into the fray; the radial remaining in production service.
As for the British/Supermarine/RR having no time or engineering capacity to install the XX into Spitfire, that's not the serious statement, right?
That "not a bright spot" on the Spitfire may have been one of the "secrets" ( purely unintentional ?) of it's ability to be upgraded. As they added heavier engines in front of the center of gravity the added bigger radiators, oil coolers, and finally inter coolers behind the center of gravity. I am sure it didn't balance out exactly but it sure made things a lot easier than adding ALL the weight on one side of the CG.Agreed. The power egg from Beaufighter, trialed at that Miles fighter, seem like a neat thing to be attached to the Spit. It also ditches the under wing radiator, not a bright spot on the Spit.
Yet it was plenty of engineering time to fiddle with Sabre/Typhoon saga? Granted, not the same companies, but the costumer was the same. The hard pressed Soviets managed to find the time to re-engine the Lagg-3, Italians can do it (3 companies at short time), but the British somehow can't pull it?
The sentence from above still stands. Making a handful of the Spitfire Mk XIIs seem to imply that there was need to the fighter that can do well under 20000 ft.
Was it inadequate compared to the Bf 109F-4? It was inadequate against the Fw 190s.
The Merlin 45 weighed about 1400lb. The R-2800 about 2300lb. Sure, the Spitfire carried a coolant system and radiator which added to the weight, but it would probably not amount to 1/3 of the difference. Also, all the extra weight would be up front, the Spitfire's coolant system's weight isn't all up front.
The R-2800-5 is 6" longer than the Merlin 45 as well. A lot of re-engineering.
The P-51 was 35" wide at the widest point. I believe that the Spitfire was narrower than that. The cowl on the R-2800 would be 54-55" in diameter.
I believe the issue was not enough XXs for both. The Hurricane needed the extra power more.
Remember also that Supermarines were working on the Griffon Spitfire as well - their first proposal for that engine installation was in 1939.
Aside from making the Spitfire more ugly, you have to ask if it improves the aero any? It certainly has a double whammy effect on weight balance - longer heavier engine up front with a front mounted radiator. It would need some balance weights.
Behind the Fw 190 and P-51A/Mustang I?
The problem here is timing. The Griffon Spit was in the works before the Fw 190 appeared. The Merlin 61 was already bench testing when the Fw 190 appeared, and had already been slated for the Spitfire - and probably why the work on installing a Merlin XX was stopped. The R-2800 Spitfire would not, I'm sure, be available before the Spitfire IX (mid 1942) or the XII (late 1942) and wouldn't have the performance of either.
You keep keying off the take-off power. The power at combat heights was much different. The Merlin 45 was good for 1230hp at 18,000ft at 12lb boost. What was the R-2800-5 good for at that altitude? Under 1400hp?
We are going round and round on the radial engine drag. We know that the P-36 had 22% more than the P-40. even if the FAT-fire has only 14% more drag than a normal Spitfire ( a 1/3 improvement for a even bigger engine) you are down to the power/drag of the Spitfire V. When the British clear the Merlin 45 for 16lb of boost it makes about 1500hp at 11,000ft. A little down from the P&W "A" but then the MK V has a lot less drag. The British aren't really interested in under 10,000ft fighters at the end of 1940 and most of 1941.
I don't know why they couldn't get the XX engine into a Spitfire easily but Edger Brooks keeps saying they couldn't without a lot of rework. Engineering changes and time are not just stuffing one engine into one airframe but designing and building the jigs and fixtures needed to make the parts in an interchangeable manner rather than "filing to fit" which is the cheapest fastest way to build one or two aircraft. A lousy way to build several hundred.
That "not a bright spot" on the Spitfire may have been one of the "secrets" ( purely unintentional ?) of it's ability to be upgraded. As they added heavier engines in front of the center of gravity the added bigger radiators, oil coolers, and finally inter coolers behind the center of gravity. I am sure it didn't balance out exactly but it sure made things a lot easier than adding ALL the weight on one side of the CG.
Russians, or more properly the Lagg "team" didn't have much choice. Either get the LA-5 going or stop production of the Lagg-3 and start building Yaks.
British were pulling it off, as noted they had been working on alternative engine installations already. How many different engine installations do you want them to work on at the same time?
And it isn't just a question of doing it at all, it is a question of doing it fast enough to actually do some good.
July 1939, sees the Italian air force request the Reggiane company install a DB 601 in a Re.2000. Not to be left out Aeronautica Macchi import a DB 601 engine and started work in Jan 1940, they get a prototype flying in August 1940, (not bad) and as a result of good flight tests is ordered into production. First production example roles out in March 1941, (14-15 months after start) first issue to Squadrons in May-June. 1941. 17-18 Months after start.
When do the British get the bright idea of sticking an R-2800 in a Spitfire to be in service in early 1942? If they can pull it off, what else doesn't get done?
There may be a need for a fighter that can do well under 20,000ft. An R-2800 powered Spitfire is not it. By the time you are done you have a new plane. You need the wing tanks from the MK VIII, A rear tank of some sort, different propeller, or late model 4 blade/5 blade several years early and/or new landing gear. You need the bigger tail, you may need to raise the cockpit so the pilot can see over the engine. And so on....
When the Notlesitung for the DB-601E was allowed (start of 1942), it was inadequate.
The German take on light planes carrying heavy powerful radials: the Bf-109V-21, or maybe Bf-109X? Pictures can be found easily, this page might be a good start:
Thanks for the assessment, Vincenzo. IMO, the performance difference between the F-4 (with 'Notleistung' blocked) and Mk.V was not so big? As to the A-0 being a trial plane, well, putting your gold-worth experienced pilots into a plane that is only partly combat suitable is/was not very wise.
I believe the Bf-109V-21 used a P&W R-1830. Heavy powerful radial ????
On the power issue. BMW information from the 1946 "Jane's" corrections welcome. followed by information from an article in Nov/ and Dec 1942 editions of "Aviation Magazine". Article available at the AEHS website. of P&W information from company Data sheets at the AEHS website.
BMW 801C take off and sea level emergency power 1600hp/2700rpm/1.32AtA. 1380hp/2700rpm/1.3AtA at 15,100ft.
Climbing power, 1460hp/2400rpm/1.25 at sea level. 1310hp/2300rpm/1.25AtA at 14,500ft.
Max Cruise, 1230hp/2300rpm/1.15AtA at sea level. 1170hp/2300rpm/1.15 ATA at 15,000ft.
From the magazine, engine report seems to be on a Do 217E engine. Maximum power for takeoff for 3 min. -- 1,580bhp. @ 2,700 rpm. @ 4.7 psi. manifold pressure.
Maximum power (emergency) – 1.585 bhp. @2,550 rpm. @ 15,750 ft. @ 4.5 psi manifold pressure.
Maximum cruising power (continuous) – 1,280bhp. @ 2,300 rpm. @ 18,500 ft. @ 2.2 psi manifold pressure.
Size of engine given as 50in with 52in being the diameter of the cowling.
"Jane's" numbers for the 801D
T-O and Emergency at sea level. 1700hp/2700rpm/1.42ata. 1440hp/2700rpm/1.42ata/18,70ft.
Climb power 1500hp/2400rpm/1.32ata sealevel and 1360hp/2400rpm/1.32ata /17,000ft.
Max cruise 1300hp/2300rpm/1.2ata /sea level and 1215hp/2300rpm/1.2ata/18,000ft.
...
A-20 stays with the R-1830s, so Martin can use the R-2600s?
The key things are timing and availability. In 1941 USA can install in it's fighters:
-V-1710 'C' series engines, either turbo (1150 HP up to 25000 ft), or non-turbo (1040 HP at 13800 ft). Neither -39, nor the engines with 9.6:1 supercharger drive ratio are available (not counting prototypes) before early and late 1942 respectively
No argument.-R-1830, single stage or turbo
-R-2800 single stage, 'A' series
-Wright engines (R-1820 and R-2600)
Comparing a R-2800 from Jan 1941 with V-1710 from late 1942 (full throttle at 15500 ft) is funny, to say at least.
I think I got us of topic or crossed threads
so I am bringing back to this one from the "different Corsair" thread.
but:
Cutting engine power by 25% is going to leave you with some rather reduced capability A-20s. And it might not free up the engines you want.
Actual not quite right. the -39 was being installed in production aircraft in mid to late 1941. Prototypes had flown in 1940 and orders for hundreds of P-40s with -39 engines had been placed in May of 1940. This is where the "timing and availability" come into play as it could take months if not over a year from the placement of an order to the delivery of the aircraft at the factory with several more weeks/months before the aircraft show up in action.
The Flying Tiger aircraft were sold to China in Jan 1941, arrived in Rangoon, Burma in June of 1941 and went into action Dec 20th 1941 as a somewhat extreme example.
As of Dec 1 1941 there were 74 P-40Es in the Philippines.
The First Allison with 9.60 gears was the F6R in 1940 but it didn't get very far, second ( 3rd) were the F14 and E12 of which 54 were built in late 1941 but these are the ones that had trouble with the supercharger gears and had to be rebuilt with 8.80 gears while a new gear housing and gears were worked on for the later F20R engine. We have difference between what was planed and what was deliverable.
Only if you kill the B-26.
R-1820 is available but a bad choice. The R-2600 is available in numbers but that is the 1600hp "A" engine as used in the A-20 and some other aircraft. about 443 of the 1700hp "B" series were built in 1941 (206 in Dec), this is the engine used in the B-25 and it was built in a different factory (except for 147 built in 1942) than the "A" series engine and used a steel crankcase instead of aluminium among other changes.
Trying for the early R-2800 powered fighter (single stage) without redoing the production schedules of the engines calls for lower powered A-20s, lower powered B-25s and lower powered B-26s ( if any B-26s at all).
Not so funny, Allison was not only promising the 9.60 gears for Nov/Dec of 1941 they were building small runs of engines and running model/type tests. The supercharger gears failed. Other improvements (like nitrided crankshafts) were incorporated in production engines of other models.
IF in the summer of 1941 Allison is promising 1125hp at 15,500ft (having first proposed such an engine in 1940) and P&W has built NO "B" seies engines and only 500-600 "A" series engines (let alone actual installed them in aircraft) AND you expect Packard Merlins to start showing up in Dec/Jan (engines were ordered in Sept of 1940) WHEN do you design/work on the R-2800 powered fighter? USAAC had ordered over 700 P-47s with turbo R-2800s in the fall of 1940.
The timing and availability of the engines does not come out in favor of a "simple, single stage" R-2800 powered fighter.
Another thread talks about America having too many types of aircraft. This is a case of trying to design a specialized aircraft to be produced for a very limited amount of time until it is obsolete.
The B-26 looks like a better way to use R-2600s than A-20, even if they make only 1600 HP at take off.
The Douglas Havoc I was good for 462 mi, with 325 gals and 2080 lbs of bombs; the A-20A was good for 525 mi with 388 gals and 2400 lbs of bombs. So we loose 10% of range, unless 'my' A-20 minus' is outfitted with 350-360 gals?
Agreed, you are right here.
My addition - the -39 engine does not offer anything in performance over the A series R-2800, at any altitude - the A has 40% more power above 14000 ft.
Yep, they gave a good account with 'sharp nosed' Curtiss.
It also calls for an early US-built fighter that can actually clash with Axis fighters while not suffering too big a performance advantage (while outperforming Japanese fighters, and able to actually climb to kill Japanese 2-engined bombers), that would be available for the Allies from summer of 1941. It calls for a carrier-borne fighter that will do it's task, even if the unexperienced controller puts it 3000 ft under the incoming bomb run, somewhere in South Pacific in 1942.
In other words, Allison has only prototypes of the '9.60' engines to promise/show, before mid 1942. In the defense of Allison, the are overtaxed with many versions of their engine, many things will be abandoned or get late.
As for when we should order the fighters - on Feb 1st 1938, the USN holds a design competition for a new fighter, to what Vought proposes a fighter with R-2800 in April 1938. The US Army issued 'Circular Proposal 39-640' in March 1939, to what Martin responded with future B-26. So, the design of the new fighter might commence in 1938.
Not a specialized aircraft, neither of a limited time of usability.
For example, Grumman might decide that there is no much point in developing a fighter that would be only slightly better than F2A, and go for the new P&W engine to power their new fighter. Six HMGs, 200-220 gals, 250-280 sq ft wing. If they keep the wing thickness at 15% (root), it can replace F4F, F6F, F8F (once the 'C' series arrives).