SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
Wow. I never realized how large the Wildcat is. I've seen them before but never side by side with a Mustang. I was usually looking for the B-17s anyway.
Can we make a faster better performing Wildcat in 1942?
- Thread starter Wild_Bill_Kelso
- Start date
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Shortround6
Major General
F4F production.
1940...............106
1941...............324
1942.............1470
1943.............1547
1944.............3130
Faster/better performing when?
Any major changes are going to cause lost production in 1941-42-early 43
It took around 1/2 year for the F4U and F6F to predominate in 1943.
What engines were in large scale production in 1940-41-42?
edit>
Total production by the end of 1943
F4F...................3437
F6F...................2557
F4U..................2466
1940...............106
1941...............324
1942.............1470
1943.............1547
1944.............3130
Faster/better performing when?
Any major changes are going to cause lost production in 1941-42-early 43
It took around 1/2 year for the F4U and F6F to predominate in 1943.
What engines were in large scale production in 1940-41-42?
edit>
Total production by the end of 1943
F4F...................3437
F6F...................2557
F4U..................2466
The FM2 (late 1943) was the faster, better performing version of the F4F and it took that long to evolve the needed aircooled radial engines. The F4F-3/4 A/B ( Martlet) variants that used lightweight single stage engines had a nominally higher power to weight ratio and did perform a bit better at low altitude in USN testing:
http://www.wwiiaircraftperformance.org/f4f/f4f-4-02135.pdf (see page 3, paragraph 5)
http://www.wwiiaircraftperformance.org/f4f/f4f-4-02135.pdf (see page 3, paragraph 5)
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When is the major question.
If Grumman and/or USN really want to have the best possible F4F, something needs to be axed. Probably the F5F/XP-50 projetcs - lot of effort and resources invested, for no actual gain. Decision for that change needs to be in effect by some time of 1938?
Shortround6
Major General
Possibly but the F5F did next to nothing about the powerplant/problem. Used the same engine/s as the Brewster F2A-2/3 and a number of other aircraft.
Not sure about the XP-50 but that might have been trying to repackage the B-17 powerplant?
That is a major part of the Problem.
Wright was producing the G200 series, in small numbers in the Spring of 1939 and would go on to make thousands of them, but the H series engines 1300/1350/1425hp versions don't start to show up until 10/42-7/44-1946.
We can argue a bit about superchargers.
P&W doesn't get the R-1830 past 1200hp until 1944?
Yes P&W could have done a better installation of the R-1830 in late 42 or in 1943 but F4F was switching over to the Wright Cyclone 9 in late 1943 anyway so what was the point?
The R-2000 doesn't show up until 1942, 1 built in July 1941 and 8 in Dec 1941 and then enough to keep up with C-54 construction. This could have been changed but an R-2000 powered F4F gets you what in 1942?
An extra 150hp for take-off and up to 2000ft. and you loose the high altitude capability. Unless P&W spends time and money on a better supercharger for the R-2000 and it will be ready when?
It doesn't really matter what Grumman does powerwise with the F4F as they are not going to get better engines to power it (F4F with a Packard Merlin?)
Which means maybe a new, skinny low drag fuselage for the F4F and that needs new production jigs and fixtures? delaying production when?
These two aircraft were taking resources away from Grumman, the resources that could've been invested into improving the F4F.
Something might've been done with wheel well covers, as well as more thought-out exit from the intercoolers - add that on the nip & tuck suggested above by different forum members and the 4-gun F4F will be faster by 20-25 mph?
Skinny F4F = all new aircraft IMO. Especially if the V-1650 is thinkered about.
It will be P&W that is supposed to supply engines of better power; granted, something more complicated, like R-2180+turbo will require that Grumman does it job.
What Grumman can take a look power-wise is taking a page from NACA experiments with individual exhausts from late 1941.
Shortround6
Major General
But they didn't perform as well at they got into the higher teens. The difference got greater when they got into the 20s.
There seems to have been a bit of confusion as to the way the planes were intended (designed?) to be used and the actual use in late 1941/early 42
A lot of performance numbers/charts given for an F4F-4 in 'four gun fighter configuration" which not only has the 4 guns but only 200rpg and taking off with 34US gallons missing from the main fuel tank. 106.5 US gal of fuel is rather less than impressive once you look past the speed and climb numbers.
Shortround6
Major General
How much do you want to delay things?
And I have no idea what the Navy was thinking with some of their requirements.
Prototype F4F-3 had four windows in the bottom of the fuselage and production F4F-3 and most F4F-4s had 2 (one each side) and they disappeared on the FM-2s.
Now this meant that the pilot could look down but the fuel tank was just about inline with the windows so this meant that fuselage had to be fat enough for the cockpit and fuel tanks (one behind the other) AND enough space for the Pilot to look down past his seat and the fuel tank and through the windows.
Attaching doors for the landing gear?
Possible but the F4F used hand cranked landing gear to begin with. How much more complication and how many more cranks in the wheel?
You also don't get quite the speed benefit on slower airplanes. You get a percentage increase not a flat 5 or 8mph increase.
P&W had figured this out but not until 1943 which is a little late. Note that the person doing the labeling seems to have forgotten about the intercoolers.
The windows in the bottom of the fuselage AIUI were a hangover from the 1930s doctrine that all USN fighters should be able to carry bombs as well as MG to suppress AA fire on enemy ships and tear up enemy carrier flight decks. The windows allowed the bombs to be aimed. The F4F was designed to carry 2 x 100lb bombs on underwing racks
I'm sacrificing the 2-engined Grumman fighters, so all hands (bar the ones working on Avenger) go to work on perfecting the F4F in 1938-41.
Attach them on the wing/fuselage junction.
Use electric motors.
Gram strategy.
5 mph from here, 5 mph from another detail that has gotten more attention (oil coolers?), 8-10 mph due to more modern exhausts, 4-5 mph due to a retractble tailwheel, 5 mph due to keeping guns number at 4, a few mph with more stremlined windscreen etc. Subtract 5-10 mph to be on conservative side.
NACA figured the benefit of individual exhaust stacks on a radial by the time Pearl harbor was attacked.
- Thread starter
- #52
Wild_Bill_Kelso
Senior Master Sergeant
- 3,231
- Mar 18, 2022
From what I gather the problem with the radial engines was that increased RPM or boost caused too much heat to build up. To solve this problem with the bigger engines later in the war they used water-injection for cooling, right? Could they use water or methanol or whatever to cool an R-1830 or 1820? Without increasing bulk by an enormous amount?
- Thread starter
- #53
Wild_Bill_Kelso
Senior Master Sergeant
- 3,231
- Mar 18, 2022
That's a really interesting point about the windows.
Don't tend to wade much into US stuff, but re the F4F, minimum mods to increase effectiveness: slipper or drop tanks by spring 1942, possibly keep 4 guns on the F4F-4. I too was thinking of the R-2000 engine to increase power but it seems it's to late, can this engine be ready earlier? If it can be ready earlier, if nothing else this should help the heavier F4F-4 at least maintain roughly the same speed/climb as the F4F-3? Put on it the same supercharger as used to the R-1830-86 or whatever mod used on the F4F.
A more roundabout way centers on the F5F which was a complete waste of time indeed. First, instead of the F5F Grumman should get a contract for the TBF, all else being equal this should fly say mid 1940, with deliveries by late 1941. So that means most VT squadrons fly TBF by Midway.
Next, they receive a contract for the F6F with the R-2600 which will fly say summer 1941, deliveries by late 1942 (may or may not be in time for Santa Cruz). Not quite sure of the speed with the R-2600, but if a combat ready F6F-1 can do 360 mph, that's a big jump from the 320 mph or so of the F4F-4, and the Zeros will be even more hard pressed than in OTL from late 1942. Perhaps keep 4 guns on this ATL F6F-1 to reduce the weight a bit for the weaker R-2600.
The F6F-3 then proceeds as planned with the R-2800, with the benefit that the production line is already well estabilished, so they might appear in combat slightly earlier, say summer 1943.
A more roundabout way centers on the F5F which was a complete waste of time indeed. First, instead of the F5F Grumman should get a contract for the TBF, all else being equal this should fly say mid 1940, with deliveries by late 1941. So that means most VT squadrons fly TBF by Midway.
Next, they receive a contract for the F6F with the R-2600 which will fly say summer 1941, deliveries by late 1942 (may or may not be in time for Santa Cruz). Not quite sure of the speed with the R-2600, but if a combat ready F6F-1 can do 360 mph, that's a big jump from the 320 mph or so of the F4F-4, and the Zeros will be even more hard pressed than in OTL from late 1942. Perhaps keep 4 guns on this ATL F6F-1 to reduce the weight a bit for the weaker R-2600.
The F6F-3 then proceeds as planned with the R-2800, with the benefit that the production line is already well estabilished, so they might appear in combat slightly earlier, say summer 1943.
Shortround6
Major General
You are not gaining all that much.
Grumman delayed work on the XF5F-1 to work on the F4F-3.
Contract for the XF5F-1 was signed June 30th 1938, First flight was April 1st 1940.
Grumman Widgeon amphibian work started Aug 1939, first flight June 28th 1940.
Grumman XP-50 contract signed Nov 25th 1939. First flight Feb 18th 1941
It took 6 months to sort out the Avenger contract. BuAer made the recommendation on Nov 3 1939 but contract for two prototypes not signed until April 8th 1940.
Grumman was working through proposals for a bigger fighter with the Design 33 and 33A In Feb 1938 which went through Design 35. After two years they started on Design 50 In Sept 1940, Mock up inspection Jan 12 1941 and contract for two prototypes signed June 30th 1941 for the XF6F-1
BTW Grumman was building the J2F Duck until 1941 when production was transferred over to Columbia Aircraft Corporation and Grumman Goose was in production from 1937 until Oct 1945.
And sometimes it doesn't matter what Grumman was working on if P&W and Wright are not completing their parts of the system. Or if something that the NACA was working on is "perfected" a couple of weeks after production tooling is completed on the existing component. Do you want it perfect or do you want it now?
Yes it can be done, but should you?
That weigh how much?
Which set up?
The NACA tested several set ups much like the set ups used on the A-20 and B-25. They helped at top speed, they hurt at cruise speeds (14 little humps/bumps sticking out into the slipstream.)
I will not get the perfect F4F, at least not on such short notice.
The 'now' part is covered by the historical F4F. The perfected part is what the people in Grumman will be working instead of on the F5F and P-50.
I should.
I don't know the extaxt weight, will be far lighter than the electric motors sometimes used to lift the U/C on other A/C so equipped.
Setup 1 was used on XP-41.
Setup 2 was used on XP-42.
Both were similar (no wonder, the same basic engine was used, although the XP-41 was the one with a better version), and, at least XP-42 setup was with without humps and bumps - it was similar to what Fw 190 used.
Shortround6
Major General
Unfortunately some of these time tables require engines that either were never built or were at least contemplated and either didn't work or never made it through testing.
P&W had been working on their two stage supercharger since 1938, They skipped right over the 2 speed supercharger until sometime in 1940.
The R-2000 supercharger was sort of short of breath. How much was common to the R-1830 I don't know. But the R-1830s were good for 1200hp from sea level to 4900ft in low gear.
The R-2000s were good for 1350hp up to 2,000ft. The R-2000 weighed just about as much as an R-1830 with the 2 speed supercharger and at over 18-19,000ft the two stage engine would give better performance. Putting a similar supercharger on an R-2000 is going to add at least 100lb. Problem is that is just for the dry engine, Trying to put more power through tooth pick props doesn't work well.
Some of the Avenger problems were because of the Navy, why it took 6 months to order the two prototypes after the 7 month design selection process I don't know.
Flight trials began on 7th Aug 1941, Getting the navy to actually order the Prototypes even 3 months earlier might have meant more than 6 Avengers at Midway (still would not have fixed the torpedoes)
Navy also wanted two stage superchargers. What they were expecting to torpedo at 30,000ft I have no idea. Now keep this in mind, Wright announced, but only delivered about 2 two stage R-2600 engines. Which did not work very well and soon disappeared never to be heard from again.
Wright R-2600 engines,
1600hp for take-off. Available in large numbers in 1940-41.
1700hp for take-off, none in 1940, 443 built in 1941, 206 of them in Dec, Production in 1942 is rather sketchy in early part of the year, it takes until June to beat the Dec total, In the worst month of 1942 (Feb) they only built 60 engines between two plants.
1900hp for take-off. Does not show up in double digit numbers until July of 1943.
Now for the reality check.
The 1700hp T-O rating R-2600 was good for 1450hp at 14,100ft no ram.
The engine in the F6F-3 was good for 1800hp at 15,500ft but with ram could hold to 18,700ft
In a British test they got 371mph in low gear at 18,700ft.
I doubt that at 16,000-17,000ft the R-2600 powered Hellcat was going to make 360mph.
What the two stage supercharged R-2600 might have done I don't know, they yanked that engine out of the F6F-1 prototype in about one month.
Seems like November 1st of 1942.
- Thread starter
- #60
Wild_Bill_Kelso
Senior Master Sergeant
- 3,231
- Mar 18, 2022
Wow so the solution may just be get FM-2 into production earlier. That could have been very helpful for the Marines and the FAA as well.
Shortround's point about the 'toothpick propellers' is also interesting. Can you put a broader bladed propeller on an F4F-3 or FM-2?
Shortround's point about the 'toothpick propellers' is also interesting. Can you put a broader bladed propeller on an F4F-3 or FM-2?
