Merlin powered carrier fighter other than Seafire

[tomo pauk]

It is not the took off that stressed the LG and airframe, but the arrested landing and the aircraft will be heavier yet with an airframe modded for that. Additionally the view over the nose is terrible and it would have been very difficult to land on a carrier.

P-40 have had its' shortcomings, flimsy construction was not one of them.
I've listed the weights of the interesting U/C gears, and P-40 can simply retain the heavy 630-700 lbs ones for CV duties, rather than reduce the strength (and weight at ~550 lbs) as they have done for later marks. Should do as good as Hellcat's 10% heavier U/C.
The view over the nose was maybe not the greatest thing, somewhere between Hurricane and Spitfire (no fuel tank between pilot and engine in P-40).
The P-40 does not have 'water brakes' - down protruding coolers, like P-51, Hurricane or Spitfire. Should be safer plane to ditch in.

The difference in drag at climbing speeds is minimal and offset by the lower wing loading.

The Spitfire I, on normal boost and with CS prop, was at 2800+ fpm range at lower altitudes, vs. 2600+ for the Hurricane I, same conditions, of course same engines.

Yes, and I stand by that statement.

Okay

See the Grumman specs for the F4F-3:

and note the performance for the overload fighter at 7432lb.

and then look at the specs for the F4F-4:
and note the performance at 7426lb and then note the discrepancy between the F4F-4 and F4F-3 at near identical weights! The time to climb to 20K ft has gone from 8.4min in the F4F-3 to 12.7min in the F4F-4 yet the weights are the same! Grumman "sexed up" the performance stats for the F4F-3/4 and then had to back away from them as it was obvious that actual service aircraft, in combat, could not hope to match Grumman's claims, and USN/USMC pilots said so in no uncertain terms.

Grumman 'sexed up' climb rating for the F4F-3. The speed rating was as it was said by Grumman, for both F-3 and F-4.

Because, for a land based aircraft it was probably made little difference to a Merlin III fighter with CS prop, so they left the TO rating at 6.25lbs, especially since pilots knew that they were authorized to use higher TO boost if it became necessary.

Could be.
Perhaps someone with a good book about the Merlin could shed some light on this and other issues?

 

[RCAFson]

P-40 have had its' shortcomings, flimsy construction was not one of them.
I've listed the weights of the interesting U/C gears, and P-40 can simply retain the heavy 630-700 lbs ones for CV duties, rather than reduce the strength (and weight at ~550 lbs) as they have done for later marks. Should do as good as Hellcat's 10% heavier U/C.
The view over the nose was maybe not the greatest thing, somewhere between Hurricane and Spitfire (no fuel tank between pilot and engine in P-40).
The P-40 does not have 'water brakes' - down protruding coolers, like P-51, Hurricane or Spitfire. Should be safer plane to ditch in.

So the P-40 gains weight for the LG and then additional weight for the retractable hook, and that hook must be able to withstand a lot more force than on a HSH.

The Spitfire I, on normal boost and with CS prop, was at 2800+ fpm range at lower altitudes, vs. 2600+ for the Hurricane I, same conditions, of course same engines.

The Spitfire I at 2800fpm (6050lb)was about 5% lighter than the Hurricane 1 (6317lb) . At similar weights (as per the Sea Hurricane 1B/ Spitfire Vc with HSH 1% heavier) there is very little difference in climb rates:

Hurricane 1/merlin 45 @ 6645lb = 7.1min to 20k ft and 2940fps at 14400ft. (Secret years, p303)
Spitfire Vc/Merlin 45 @ 6965lb = 7.9min to 20k ft and 2650fps at 14900ft. ( http://www.spitfireperformance.com/aa878.html )
The other climb trials reported by Williams and in The Secret Years show some variation by weight but probably average to a similar result as for the Hurricane 1/merlin 45/

Grumman 'sexed up' climb rating for the F4F-3. The speed rating was as it was said by Grumman, for both F-3 and F-4.

the -3/4 use the same engine yet at the same weights the -3 is stated to about 10-12mph faster. The logical conclusion is that -3 performance was actually about the same as Grumman finally admitted for the F4F-4 at ~7426lb in Oct 1942.

 

[Greyman]

Perhaps someone with a good book about the Merlin could shed some light on this and other issues?

Emergency boost for take-off probably isn't in the Pilot's Notes for any single-engine fighter, but I'm sure it happened.

 

[Juha]

The fact is that Hurricanes did very poorly against Zeros and Oscars during the early part of war in FE, even CW Brewster Buffalos achieved better exchange rate than Hurricane and with its under fuselage radiator Hurri was a lousy ditcher. Difficult to see why would USN/USMC have been interested in Hurricane.

Juha

 

[FLYBOYJ]

with its under fuselage radiator Hurri was a lousy ditcher. Difficult to see why would USN/USMC have been interested in Hurricane.

Juha

Great point!

 

[wuzak]

The Spitfire I at 2800fpm (6050lb)was about 5% lighter than the Hurricane 1 (6317lb) .

Yes, it is.

At similar weights (as per the Sea Hurricane 1B/ Spitfire Vc with HSH 1% heavier) there is very little difference in climb rates:

Why do you expect a Sea Hurricane to be similar in weight?

Hurricane 1/merlin 45 @ 6645lb = 7.1min to 20k ft and 2940fps at 14400ft. (Secret years, p303)
Spitfire Vc/Merlin 45 @ 6965lb = 7.9min to 20k ft and 2650fps at 14900ft. ( Spitfire Mk V AA.878 Report )
The other climb trials reported by Williams and in The Secret Years show some variation by weight but probably average to a similar result as for the Hurricane 1/merlin 45/

Was there actually any Hurricane Is fitted with Merlin 45s? Or is that a manufacturer's estimate for the Hurricane I/Merlin 45?

The Spitfire Vc as tested had the 2 x 20mm + 4 x 0.303" armament option. What armament was in the Hurricane I/Merlin 45?

Hurricane II Z-3564 Trials Report has the climbing performance of the Hurricane II as 2710ft/min @ 8300ft and 2160ft/min at 15,700ft at +9.8psi and +9.4psi boost respectively. Time to 30,000ft is 17.0 minutes.

Of course with the 45 in place of the XX some 65lbs will have been saved (from engine weight), but there will be a loss of low down climbing perfromance.

The weight as tested here was 7333lb: http://www.wwiiaircraftperformance.org/hurricane/z3564-weights.jpg

Not sure if that was the 8mg or 12mg version.

Time to climb for Spitfire Vc AA.878 was 14.3 minutes at normal rating with +9.0psi boost.

(Time to climb to 30,000ft for Spitfire I N.3171 was 16.4 minutes with Merlin III and maximum boost during the climb test of +6.4psi, FWIW. Spitfire Mk I N.3171 Trials Report)

 

[RCAFson]

The fact is that Hurricanes did very poorly against Zeros and Oscars during the early part of war in FE, even CW Brewster Buffalos achieved better exchange rate than Hurricane and with its under fuselage radiator Hurri was a lousy ditcher. Difficult to see why would USN/USMC have been interested in Hurricane.

Juha

The key point is to examine similar tactical situations.

The Hurricane was a lousy ditcher but the survival rate of pilots who had to ditch was pretty good. Including combat and ditching of 8 aircraft only one of 8 Sea Hurricane Ia pilots was lost in action.

 

[RCAFson]

Why do you expect a Sea Hurricane to be similar in weight?

The Sea Hurricane 1B (per the data card) was 7015 Ib versus a Spit Vc at 6965lb. A Sea Hurricane IIA would weigh about the same as a Hurricane IIB.

Was there actually any Hurricane Is fitted with Merlin 45s? Or is that a manufacturer's estimate for the Hurricane I/Merlin 45?

Hurricane I P3157 was used as a test bed for the Merlin 45 in Dec 1940, and was the aircraft whose performance is stated above.

The Spitfire Vc as tested had the 2 x 20mm + 4 x 0.303" armament option. What armament was in the Hurricane I/Merlin 45?

The Hurricane 1 had 8 x .303mgs.

Hurricane II Z-3564 Trials Report has the climbing performance of the Hurricane II as 2710ft/min @ 8300ft and 2160ft/min at 15,700ft at +9.8psi and +9.4psi boost respectively. Time to 30,000ft is 17.0 minutes.

Of course with the 45 in place of the XX some 65lbs will have been saved (from engine weight), but there will be a loss of low down climbing perfromance.

The weight as tested here was 7333lb: http://www.wwiiaircraftperformance.org/hurricane/z3564-weights.jpg

Not sure if that was the 8mg or 12mg version.

Time to climb for Spitfire Vc AA.878 was 14.3 minutes at normal rating with +9.0psi boost.

(Time to climb to 30,000ft for Spitfire I N.3171 was 16.4 minutes with Merlin III and maximum boost during the climb test of +6.4psi, FWIW. Spitfire Mk I N.3171 Trials Report)[/QUOTE]

Climbing trials tend to vary depending on tested weight. As i stated, a Sea Hurricane IIa weighs about the same as a Hurricane IIB. The Spitfire V climb tests are also done with climb RPM boosted to 3000rpm above 20k ft (depending on test) which improves boost and climb over the Merlin XX which was held at 2850rpm during the test even though 3000rpm, above 20k ft. during climb was also permitted on the Merlin XX.

 

[wuzak]

The Sea Hurricane 1B (per the data card) was 7015 Ib versus a Spit Vc at 6965lb. A Sea Hurricane IIA would weigh about the same as a Hurricane IIB.

So, about 7300lb?

Hurricane I P3157 was used as a test bed for the Merlin 45 in Dec 1940, and was the aircraft whose performance is stated above.

OK. Didn't know that happened.

Even so, the time to climb performance is apparently less than the Spitfire I with the Merlin III, going by time to 30,000ft.

Also, since you are showing the performance of the Hurricane I with the Merlin 45, is it not logical to compare that to a Spitfire VA, also with the 8 mg armament?

In that case, Spitfire VA X.4922 was tested at a weight of 6450lb (all up weight in service) and had a peak climb rate of 3140ft/min @ 14,400ft and time to climb of 12.9 minutes to 30,000ft.

Spitfire Mk VA X.4922 Report

Climbing trials tend to vary depending on tested weight. As i stated, a Sea Hurricane IIa weighs about the same as a Hurricane IIB. The Spitfire V climb tests are also done with climb RPM boosted to 3000rpm above 20k ft (depending on test) which improves boost and climb over the Merlin XX which was held at 2850rpm during the test even though 3000rpm, above 20k ft. during climb was also permitted on the Merlin XX.

The Spitfire V tests with Merlin 45 used 3000rpm for combat climbs and for normal climbs above 25,000ft. At 26,000ft and 3000rpm the Merlin 45 is using a mere +2.8psi boost in AA.878!

 

[OldSkeptic]

Sea Hurricane?

Needs a wing fold for the US. Needs more fuel.

P-39 needs?

A new Airplane? The Airabonita used tail dragger gear and a bigger wing and light armament (cowl guns were .30 cal) which in fact was never installed and still failed carrier qualification at 6742lbs gross and 5352lbs empty. Service P-39s went around 6200-6300lbs Basic (empty equipped= guns,armor, radios, etc but NO fuel,oil,ammo) figure 7300-7400lbs for clean without wing guns (?). And that is with 120 gals fuel.

P-40?

see Zeno's or Flight manuals. P-40E needed 1050ft of runway at 7500lbs 0 wind. The Army fighters need a more runway than the navy fighters. In some cases a LOT more. The fact that Army fighters were flown off carrier decks in ferry operations (with less than full fuel tanks and little or no ammo, in fact in some cases with some guns removed) does NOT mean they are suitable for day in/day out carrier operations with just a few minor "tweaks". For Navy use they NEED full guns and ammo, full tanks if not drop tanks.

AN F6F can take-off in less distance carrying a drop tank and a 1000lb bomb than a P-39 can clean.

Allison(or Merlin single stage Mustang)?

When does it show up and what gets delayed because you are basically sticking a new wing on it? leading edge slats, new flaps, extended wing tips (which still have to meet the "G" load requirement). And according to one chart ( and it could be in error?) an Allison powered P-51A (clean) needs around 340 feet more runway than a P-40E (Clean). P-51Ds needed less runway even when heavier because they had more power.

Admiral Fletcher could request or suggest anything he wanted. He was not an aviator and may not have had a good understanding of what made good carrier planes, He knew what he had wasn't working (lacking performance) and was looking for a quick solution. There wasn't one.

By and large agree, but to add:

The P-40 performance was (even with a Merlin) woeful. The Hurricane was obsolete in 1940, performance also woeful.
P-51 landing performance was poor, for a carrier lethal (yes they tested it).
P-39 already woeful in performance ....

For all of them their performance would also deteriorate when 'navalised' (extra weight and all that).

So there was not an airframe, except the Spitfire, that could even have a hope in hell of matching ETO land based aircraft (note that none of the pre late 44 USN fighters could either, the Hellcat, for example, could just about match a Spit Mk V ....with a 2 year separation in time).

 

[tomo pauk]

The speed of the P-40F (Merlin aboard) was in the ball park with Sptfire V, on same boost. The RoC was lower, due to greater weight of the P-40. The P-40F have had more fuel, though (part of the greater weight) - 131 imp gal vs. 84 imp gal for the Spit V.

So the P-40 gains weight for the LG and then additional weight for the retractable hook, and that hook must be able to withstand a lot more force than on a HSH.

The P-40 does not gain any weight for the LG beyond 695 lbs - it is already a strong (and heavy) piece of the A/C. The later marks used lightened LGs, 1st by ~150 lbs, than by another 100 lbs, due to use of magnesium rims. The navalized P-40 can retain the early, strong LG. Arresting gear weighted 36-37 lbs for the Hellcat, per AHT.

the -3/4 use the same engine yet at the same weights the -3 is stated to about 10-12mph faster. The logical conclusion is that -3 performance was actually about the same as Grumman finally admitted for the F4F-4 at ~7426lb in Oct 1942.

The -4 have had two extra HMGs and their chutes, that will cost some speed. The -4's wing will also cost some speed due to wing fold joint.

Emergency boost for take-off probably isn't in the Pilot's Notes for any single-engine fighter, but I'm sure it happened.

Probably it happened. It is really too bad that Merlin does not have the equivalent of the 'Vee's for victory', that will dig deep and really show us the wartime usage, beyond the manuals.

 

[oldcrowcv63]

Hurricanes were available in North America, in some numbers prior to Dec 1941 so one or more of these could have been converted to a Sea Hurricane for deck landing trials.

If one or more could be procured, no doubt it could be accomplished but I expect the motivation to do so was seriously lacking and I suspect all production was in response to a customer demand so it may have been difficult to get one or a few released… my pure speculation.

Actually, not that many (a couple hundred maybe) and the F4F-F didn't begin production till Jan 1942, IIRC.

XF4F-4 first flight was 14 April, 1941 with USN delivery in May. As noted previously, first production F4F-4's appeared at the end of 1941 with 5 delivered to the USN. Production of folding wing Martlet II's for the RN's FAA began October 4, 1941!! with 48 delivered by year's end.

We're talking maybe a dozen HSHs per CV, and I think the USN was resourceful enough to tackle that problem.

That would appear to be a reasonable number assuming that, with all the uncertainties discussed and to be discussed, that it's concluded to be an effort worth making…Although, it is a bit light for typical assigned CAP numbers in late '42 which seemed to have ranged from between 35 to 50+ F4F aircraft from multiple carriers. If a dozen HSH were embarked after the introduction of the F4F-4, what would be the impact on the air wing for a Yorktown class carrier?

There are real examples of this drawn from the literature often cited here. For example, on April 1, 1942, VF-6 operated with mixed type squadron equipped with 23 F4F-4 and 4 F4F-3s. On April 7, this was changed to 22 F4F-4 and 5 F4F-3 (the -3s were hung from the overhead). Most relevant was the air wing composition on April 28 when the Enterprise and Hornet then presumably operating air groups nominally composed of ~27 F4F-4, ~36 SBD and ~15 TBD also carried respectively 10 and 11 VMF-212 F4F-3s 1 SNJ (on Enterprise) bound for Efate. Based on subsequent events, that appears to be perhaps over a dozen more aircraft than the maximum operating air wing size would prove to be… In late 42, operational composition apparently changed again to be something like 36 F4F-4, ~24 SBD and ~12 TBF. In other words, the CV type could typically comfortably operate about 72 to a maximum of about 78 aircraft although it might carry as cargo another dozen or so hung from the hangar overhead.. The options for embarking a dozen HSH appear to be either to reduce the strike component by a similar number or reducing the number of op-ready F4F-4 by about 5 F4F-4 for every 2 HSH. That suggests a choice that a Yorktown class carrier can either embark 30 F4F-4 or a dozen HSH. That can't be correct! if we take just area and look at the nominal fixed-wing carrier airwing at the start of the war it was 72: 18 VF, 36 VSB 18 VT. One F4F-3 has an area of 1,092.5 sq. ft. vs the HSH's 1,290 sq. ft. The F4F-3 has 85% of the footprint of the HSH so 18 F4F-3s corresponds to 15 HSHs. In the final analysis it looks like a dozen HSH's would displace all but about 10 to 15 F4F-4s.

Since escort missions absorbed about 10 F4F, it looks like a dozen HSH would constitute the standard CAP. Mixing types for CAP would create air-ops cyclic problems for the aircraft with dissimilar endurance. Hanging Drop tanks on the HSH at the late stage in the war would not even out the problem since the CAP F4F-4 would also typically be carrying a drop tank. It just seems like if increased performance is what you are looking to achieve, you are going to pay penalties that may be unacceptable on a regular basis. I think there is more on this to be discussed.

It wouldn't have taken a whole lot of clairvoyance in mid 1941 to see that the FAA was short of fighters, and that the USN would be too in a shooting war, so a joint Cdn/USA project to produce Sea Hurricanes would have made some sense, especially as the conversion kit had already been engineered in the UK and the Hurricane was in production in Canada (albeit in small number prior to large scale Packard production). Not a completely likely scenario, but not completely implausible either.

Sorry RCAFson, but I think this is the most unrealistic of statements. Considering the opinion of the west regarding the IJN's capability as a potential adversary and the resultant procurement of large numbers of obsolescent aircraft for future use in the Pacific theater as war clouds gathered, by virtually all the western allies, I can't imagine anyone saying or thinking, "We (the USN) are going to be faced with (what appears to be) a crisis in carrier fighter performance in late 1942 facing the IJN." That would suggest the A6M's performance wasn't the shock that is well recorded in the histories of that period. Even hollywood accepts that!

The ideal fighter might have been a Sea Hurricane II with 4 x .5in with 350rpg (or 8 x .3in with 500rpg) and a couple of 15g internal wing tanks in lieu of the outer guns on the Mk IIB wing. This would have given the FAA and USN a useful addition to the F4F that was carrier ready and also well suited to base defence.

I'd expect the USN to opt for the 4x .50" armament since that was a familiar suite, but am wondering about that comparison to the HSH established performance with its standard quip and ammo load.

 

[oldcrowcv63]

I do find this notion of a USN HSH-bolstered air-wing interesting, although it seems extremely speculative and unlikely to have been effected in time to contribute to changing any of the events of 1942 in a substantial way, I can think of at least one instance when it might have proven very beneficial to the outcome. I am not convinced the events in mind could not have been altered by a differently configured F4F, but need better information on aircraft climb performance than I now have. I have one source of performance on the HSH, and that is here:

K5083 - Technical Data Part II - Mk. II

Any Help?

Any other sources, I should be looking at?

 

[Greyman]

Probably it happened. It is really too bad that Merlin does not have the equivalent of the 'Vee's for victory', that will dig deep and really show us the wartime usage, beyond the manuals.

Had a look at a few of my Pilot's Notes and there is indeed provision for 'pulling the plug' on take-off for many fighters.

 

[wuzak]

I do find this notion of a USN HSH-bolstered air-wing interesting, although it seems extremely speculative and unlikely to have been effected in time to contribute to changing any of the events of 1942 in a substantial way, I can think of at least one instance when it might have proven very beneficial to the outcome. I am not convinced the events in mind could not have been altered by a differently configured F4F, but need better information on aircraft climb performance than I now have. I have one source of performance on the HSH, and that is here:

K5083 - Technical Data Part II - Mk. II

Any Help?

Any other sources, I should be looking at?

Thanks for the link Oldcrow.

If that data is accurate, the Sea Hurricane IIB was 20mph slower than the Hurricane IIB in level flight (320mph vs 340mph), but only marginally slower to 20,000ft. This would make it no faster than an F4F?

In any case, would the USN be after an incremental performance increase or a quantum leap? The latter is suggested by history, where the F4F was replaced by the far more capable F6F and F4U.

The Sea Hurricane coudl not offer that.

 

[oldcrowcv63]

The question on my mind is whether a small difference in climb rate might have made a difference in the total number of CAP that managed to actually engage the initial IJN VB attack on the Hornet during the Santa Cruz Battle. Seven of the defending CAP missed the intercept during their climb to meet the inbound IJN VB Chutai of seven VALs that ultimately scored three hits on Hornet. What makes the judgment difficult is the seven climbing F4F actually passed over the seven VALs which were about a thousand feet below them. if they had reached their intended altitude a bit earlier they might have been in horizontal flight and been able to make both an earlier detection and set up a more effective beam attack instead of the tail-chase which actually evolved. The initial CAP intercept by Eight F4F was effective taking most of the seven IJN VB at least temporarily out of the fight despite absorbing the attention of all escorting A6Ms but these F4F's had been orbiting at 10,000 feet when alerted. The other seven F4F mentioned above were newly launched from Hornet.

The question is: in what A/C configuration was the CAP deployed. Was it in a "fighter" or "overload-fighter" configuration. if the latter, full tanks, maximum ammo load and 6 guns, then some improvement in performance might have made a difference. If the CAP was in the 'fighter' configuration then it was probably performing about as good as an F4F-4 could perform so perhaps even a small improvement might make a difference. Could the HSH provide the margin? I suspect the only hope of finding out is from Rich Leonard or perhaps the ship's or squadron's logs.

This is so speculative with so many variables, its impossible to say for sure whether better performance would have made a difference in this situation… but (this) one can't help wondering.

 

[oldcrowcv63]

Thanks for the link Oldcrow.

If that data is accurate, the Sea Hurricane IIB was 20mph slower than the Hurricane IIB in level flight (320mph vs 340mph), but only marginally slower to 20,000ft. This would make it no faster than an F4F?

In any case, would the USN be after an incremental performance increase or a quantum leap? The latter is suggested by history, where the F4F was replaced by the far more capable F6F and F4U.

The Sea Hurricane coudl not offer that.

You are most welcome. I think RCAFson might have some additional, relevant sources against which these numbers might be compared. I think the real potential benefit of a HSH IIB would be as RCAFson suggested as an interceptor because of its superior climb rate compared to the F4F-4.

 

[oldcrowcv63]

The money shot:

 

[RCAFson]

Thanks for the link Oldcrow.

If that data is accurate, the Sea Hurricane IIB was 20mph slower than the Hurricane IIB in level flight (320mph vs 340mph), but only marginally slower to 20,000ft. This would make it no faster than an F4F?

In any case, would the USN be after an incremental performance increase or a quantum leap? The latter is suggested by history, where the F4F was replaced by the far more capable F6F and F4U.

The Sea Hurricane coudl not offer that.

The Sea Hurricane 1b offered better performance below the F4F-4s critical altitude:

Naval air combat typically took place a relatively low altitudes, but if higher altitude was required then a higher climb rate would be most beneficial while the IIA would have been better at all altitudes.

Just plug the Zero maximum speeds from here:
http://www.ww2aircraft.net/forum/av...r-other-than-seafire-39549-4.html#post1118596
into the above to see what I mean

 

[tomo pauk]

Again the chart with F4F-4 with Cyclone???