1000-1200 HP: long range fighter vs. interceptor?

[oldcrowcv63]

Reading accounts of P-40E long range missions in early 1942 in SE Asia during the PI campaign and the defense of Java, it looks like combat-loaded P-40s with drop tanks could manage one-way ranges approaching 550 miles without combat and with little reserve. I'd expect the range of the earlier and lighter B C marks to exceed that distance. That would seem to put the P-40B C in the ballpark of 1940-41, contemporary F4F ranges and probably something a bit less than the lighter, lower-performing F2A-1 -2.

 

[tomo pauk]

Hmm... the P-40B + Merlin III/X/XII/XX = our best candidate?

 

[pinsog]

Wasn't the Zero doing this on 950 hp? Didn't the Zero handle all Allied fighters in a 1v1 fight including the Spitfire and Hurricane up until the Hellcat, Corsair and P38 arrived?

 

[Glider]

I don't know the range of the Machi 202 but I do know that it could carry drop tanks and was operational in 1941. It had a good performance, was very agile and I personally would back it against a P40B. Does anyone know about its range with drop tanks?

 

[Aozora]

Looks like there's going to be a rasher of baconed posts, with members egging one another on and generally hamming it up, leading to pork quality threads - it just isn't kosher!

 

[tomo pauk]

I was able to find the range on internal fuel only. The latest series were outfitted with 2 x 33 imp gal tanks. The 551 lbs of fuel amounts to ~77 imp gals, ie. less fuel than Spit. The wing of the MC.202 is as good as unused, re. armament and fuel.

Wasn't the Zero doing this on 950 hp? Didn't the Zero handle all Allied fighters in a 1v1 fight including the Spitfire and Hurricane up until the Hellcat, Corsair and P38 arrived?

Indeed, Zero was able to provide useful service as a long range fighter. It's successes show that an air defense fighter must be a part of well 'designed' and led air defense network, if it's to be successful; if not, the LR fighter has most of advantages.
We can note that Spitfires were able to forestall the attacks at Darwin, once some technical issues were rectified, and it took some time for the air defense network to work properly (giving enough time for the Spits to climb and form the units). It probably took time for Spitfire pilots to employ slashing attacks (boom and zoom) vs. IJN planes, without entering into turning fights with Zero.
The Darwin example also shows that a defending fighter need to have decent amount of fuel, in order to chase down the retreating intruders.

 

[oldcrowcv63]

Strangely enough the P-40E began to show some very modest air-to-air success as an interceptor over Darwin in the late Spring and early summer of '42. USAAF pilots were working out tactics and there is some circumstantial evidence that some flights of defending fighters appear to have thrown armament and ammunition overboard to reduce their weight and improve aspects of their a/c's performance. How widespread this practice became is unknown (and may be unknowable, unless there are any surviving pilots or armorers from that period). But it seems to have amounted to a whittling away of the Zeros reputation of invincibility after the initial shock of its appearance.

That seems to have been the start of the battle of attrition the lightly armored and armed A6M couldn't win.

Especially with the advent of the F4F-4 in the Fall of 1942, which, for all its many performance deficiencies as a fighter and interceptor, could climb to high altitude without the significant loss of performance of the P-40E. The battle of attrition apparently reached its climax on October 18, 1942 over Guadalcanal when CO of the VMF-212, Lt. Col. Harold 'Joe' Bauer exhorted his pilots that "When you see zeros dogfight them" Apparently he recognized or intuited that the quality of IJN Pilots was slowly declining with losses fighting so far from their bases or that the sturdiness of the F4F and improved tactics allowed it to go head-to-head with the better performing A6M…. Of course, the USMC USN pilots had the home team advantage of fighting over generally friendlier geography: Veteran pilots being relatively irreplaceable compared to their aircraft.

However until that time, and until the arrival of the Spitfire, F4U and P-38, the A6M certainly remained a formidable opponent. Not that it wasn't after they appeared but ruling the air combating the new generation of allied a/c wasn't in the cards.

But certainly in 1940-41 it was the most effective long-range escort of its time taking the allies by nearly total surprise and who were only able to respond with obsolescent inadequately performing interceptors unable to counter its attacks.

 

[OldSkeptic]

T
The escort fighter doesn't have to have all the performance of the interceptors because the latter's primary mission is to take out the bombers.

Precisely. Provided good tactics are used by the escort fighter they will always have a tactical advantage over the interceptor. Apart from anything else they will have a height advantage, which they can have reached well before they head over enemy territory (and in a nice fuel consumption minimisation way).

Therefore they don't need (though it always useful) the climb rates of the interceptor. The example of the P-47, especially the early ones, comes to mind. Good speed of course, but it only has to be competitive (again being superior is a bonus).

Therefore back to a MR/LR Spit as an example. Even with (for a MR version) an extra 350 lbs in internal fuel it will still outclimb anything in 1940/41 except a 109.
Careful attention to the cleanness of the planes (taking a leaf out of the PR boys book) can ensure that the speed impact is minimal. Dropping the tank holders as well as the external tanks helps too*.

Careful planning means that the escort fighter is at a good fighting weight and height and running off the drop tanks during the main danger period for escort (lower loaded ones can cover the earlier parts, both going and returning). Therefore taking the Spit on a 300 mile combat mission, the main danger area escorts are only carrying maybe as little as an extra 200-300lbs (and diminishing). That's not enough to close the gap in performance given the escort fighter is already at altitude. 'Boom and zoom' are the primary fighting tactics by escort fighters (at least for the 1st pass), the idea is to break up the interceptors and make bomber attack difficult.

A bunch (of varying in number of course) interceptors trying to form up and get into position for an attack run have a much harder job if they have to look over their shoulder all the time to avoid being bounced by the escorts.

Again to be fair clever tactics by the interceptors can help minimise that (for example full bore head on attacks in the first pass, covering attacks on the escorts first and so on) but it is difficult to beat escorts (again with them following good tactics) without taking significant losses.But then we are into attritional warfare again and if you can outproduce the other side in fighters (and pilots) then you will win over time.
As happened in both the BoB and the Air Battle of Germany.

In the Bob, despite being controlled by the finest air tactician of the war, the RAF still suffered serious losses against the escorts and the bombers themselves. But it could take it, the Luftwaffe couldn't either in escort fighters or in bombers, therefore it lost.

In the ABoG the bombers and the escorts suffered serious losses too, but again the USAAF could take it, while the Germans couldn't (poor German tactics didn't help of course). In that battle the early P-47s suffered serious performance disadvantages, with poor climb and poor level acceleration, but because they had the tactical advantage (height basically) they could still inflict serious attrition on the interceptors, so much so that the defence withdrew attacking the bombers in areas where the escorts could reach (which was actually a serious tactical mistake by the Luftwaffe).

I use the Spit as an example for this period because I cannot see any other alternatives at all in the west at that time (40/41). A P-40, with even a Merlin XX (which wasn't really available then anyway), simply would have inferior performance to a similar engined Spit that carried extra fuel. Before you even put a drop of fuel into the thing it is already much heavier. So I fail to see the logic of saying a fueled up Spit cannot do the job (at least for MR stuff), while an already heavier (and aerodynamically inferior) P-40, which also has to carry the same amount of fuel as well, will somehow be better?

All these depend on good planning and tactics. If the escorts use poor ones then their loss rates will be much heavier (as well as the bombers). If the defenders use poor ones then the escorts job will be much easier. If they both use good/poor ones at the same time then the odds are closer. In all cases we are just changing the attrition rates.


* I mention the racks, because when you look at the P-51s you see the bomb/fuel racks on the wings, these were semi-permanent fittings. These cost it 10mph, which it could afford though other planes couldn't of course, but the alternative was to have droppable racks (as per the Malta Spits for bombs) therefore returning full performance (allowing for the extra fuel weight).

 

[stona]

The problem for the RAF's interceptors during the BoB was time. They didn't have enough time to reach the ever increasing altitudes at which the Germans arrived. It took much longer for a Spitfire to reach 25,000 ft than for a Luftwaffe formation to fly from Cap Gris Nez to Dover, even if it took off as the raid left the French coast. They almost invariably struggled to gain sufficient altitude.
This wasn't a problem for the Luftwaffe later in the war when the USAAF made deeper penetration raids and they made the Americans pay for it.

Cheers

Steve

 

[tomo pauk]

Hi, Old. Agree with pretty much you're said, but these two:

...
I use the Spit as an example for this period because I cannot see any other alternatives at all in the west at that time (40/41). A P-40, with even a Merlin XX (which wasn't really available then anyway), simply would have inferior performance to a similar engined Spit that carried extra fuel. Before you even put a drop of fuel into the thing it is already much heavier. So I fail to see the logic of saying a fueled up Spit cannot do the job (at least for MR stuff), while an already heavier (and aerodynamically inferior) P-40, which also has to carry the same amount of fuel as well, will somehow be better?...

There were P-40s and then there were P-40s. The P-40, P-40A and P-40B were pretty light weight; later models got overweight. The P-40B was featuring the armament weight of the Spitfire I II/Hurricane Is (give or take), the fuel tanks were self-sealing, armor was installed, all while weighting 6835 lbs when 120 US gals was carried (100 imp gals). On that weight, it was capable for 352 mph at 15000 ft. Spit II was good for 345 mph at 15000 ft, on 6172 lbs.
Sick a Merlin III/XII on it and it will be around 360 mph between 15-20000 ft*. And it can be fueled up to 160 US gals (133 imp gals) internally.
BTW, aerodynamic superiority/inferiority involves not just a basic wing shape (Spit was perhaps the world champion in that), but also the layout of cooling system, how good/bad the wheels were covered when retracted etc. - in those things Spit have had space for improvement.

* I mention the racks, because when you look at the P-51s you see the bomb/fuel racks on the wings, these were semi-permanent fittings. These cost it 10mph, which it could afford though other planes couldn't of course, but the alternative was to have droppable racks (as per the Malta Spits for bombs) therefore returning full performance (allowing for the extra fuel weight).

The racks at P-51C and earlier were 'stealing' 12 mph, from P-51D and further only 4 mph.

added: at ~17000 ft, those Merlins were making about 1000 HP, vs. V-1710-33's ~950 HP.

 

[Glider]

Hi, Old. Agree with pretty much you're said, but these two:


There were P-40s and then there were P-40s. The P-40, P-40A and P-40B were pretty light weight; later models got overweight. The P-40B was featuring the armament weight of the Spitfire I II/Hurricane Is (give or take), the fuel tanks were self-sealing, armor was installed, all while weighting 6835 lbs when 120 US gals was carried (100 imp gals). On that weight, it was capable for 352 mph at 15000 ft. Spit II was good for 345 mph at 15000 ft, on 6172 lbs.
Sick a Merlin III/XII on it and it will be around 360 mph between 15-20000 ft*. And it can be fueled up to 160 US gals (133 imp gals) internally.
BTW, aerodynamic superiority/inferiority involves not just a basic wing shape (Spit was perhaps the world champion in that), but also the layout of cooling system, how good/bad the wheels were covered when retracted etc. - in those things Spit have had space for improvement..

But at the same timescale as the P40B the RAF were introducing the Spit V, the Germans the 109F both of which had a seriously better performance.

 

[OldSkeptic]

Thanks Glider, about to post that. By that time 1,200bhp was fading memory for the Spits and 109s.

More ever, basic to escort/interceptor tactics. the optimum coverage was basically 3 groups of escorts (the Germans experimented with this in the Bob and used it successfully at times, hence Park's need to 'peel' off the escorts).

High cover, at least, preferably more, 10,000ft above the bombers (assuming they are coming in about the 20,000ft mark), forward sweep and 'loose close' cover (ie not too close, but as a reserve if nothing else).

The sweep is to break up interceptors forming up (ideally below them), the high cover to swoop down on those that get through, the L/C cover for the remainder and to get those who pass, reform and attack again.
Takes a lot of escort fighters (back to the numbers game again) of course (more so when you have staged escorts). But it presents the defenders with the hardest possible options.

The high cover has to be attacked, or at least disrupted before you can really hammer the bombers. But to do that means gaining even more height and having to get through the sweeps. The timing has to be really good to feed through the anti-escort fighters first, before the bomber killers get there. Even if the defenders have a performance advantage at all those altitudes, it is not going to be that much and not enough to push the kill/loss ratios up enough to really punch through the escorts without taking significant losses (attrition again).

Of course you can also play with clever tricks, sneeking in smaller (thus harder to see) groups of defenders (flight/squadron sizes) which will take a toll on the bombers. Vectoring in from different angles also helps, since it disrupts the escorts and makes their job a lot harder (ideally you hit the bombers from all sides with small'ish groups of defending fighters). Full bore frontal attacks (ideally from a shallow dive) on the bombers and so on.
This may not be optimum way to hammer the bombers, but it is the optimum way to hammer escorted bombers.

That is where the Luftwaffe failed in the ABoG. It's tactics were unimaginative and fragile. Plus they even repeated the RAF's 'big wing' mistakes (and if anyone should have know better it was them) where the sweeps had a field day.
They never tried to disrupt the escorts at early stages (ideally making them drop their tanks too soon). That was one weakness of the staged escort approach. The arriving escorts were vulnerable to being bounced on their approach, not so much to suffering significant losses, but to having to dump their tanks early, before they rendezvoused with the bombers.
Even squadron level attacks would have put real pressure on the escorts (basically cause them to have to increase their numbers significantly as you would need escorts for the escorts, for those approach phases).

They were too dependent on their poorly performing twins (basically 110s), when they were taken out (and the escorts had a field day with them) their successful '43 tactics collapsed (hence their victory at that time was very fragile).

They became bomber obsessed and seemed to be unable to adjust to the new escorted phase, where you need to disrupt and inflict attrition on the escorts too, before you can successfully hammer the bombers.

So in '43 the Luftwaffe won the attrition war, but after that they lost it. Note that it wasn't just the P-51, it was also significant changes in escort strategy and tactics (that great Doolittle again another brilliant air tactician). At the strategic level, their fighter and pilot production was too low to take that attrition, while the Americans could (though at times just) manage it.

So, using my previous post's point, by the Mid 44 period the USAAF escorts had superior tactics and could handle the attrition (their better equipment was a bonus, but of the Mustang was 20 or even 30mph slower it would have not made much of a difference). The Luftwaffe used poor tactics (which accelerated its attrition) and couldn't. So it lost.
To be fair, even with better tactics, their production levels were too low to win, but they could have strung it out longer and inflicted greater losses.

For them to win it would have taken the correct decisions to be made in '42 to build sufficient production and training capacity, numbers and develop the C&C systems and tactics.
They didn't, so their only remaining hope was to hammer the Americans enough in the early stages for them to lose their will to fight, which they partially achieved for a short time, but it was betting high on a pair of twos, the odds were well against them.

 

[tomo pauk]

I have made this proposal:

Hmm... the P-40B + Merlin III/X/XII/XX = our best candidate?

Historical P-40B, with 100 imp gals aboard, was performing as the SpitI/II/Bf-109E. The BoB fighters received the uprated engines and more weight, the P-40 received mostly more weight. The P-40D grossed at 7740 lbs clean, ie. 900 lbs more than P-40B, since it was now carrying 148 US gals of fuel (123 imp gals, 3 more than Spit VIII). The P-40E received 2 more HMGs ammo, with other models following suit. Clean it went to 8290 lbs.
The Spit V with 4 cannons was at 6917 lbs, the ones with 2 cannons were a tad lighter. Comparing it with P-40F (= 364.5 mph at 19,270) , it was some 7-10 mph faster, but RoC was way better for the lighter Spitfire.
The Bf-109 was both more powerful,lighter and smaller, while featuring improved aerodynamics vs. the 109E. No wonder it was able to outperform the P-40 easily.

In case the Merlin XX or 45 is mounted at the P-40B as-is, the weight difference will remain much closer, so the performance will be better. And the plane has much more internal fuel than SPit or 109, making it better for long range work.

 

[OldSkeptic]

Waste of a good engine. A compatible Spit V against a P40F was 10-30mph faster at all altitudes, 500-1000fpm+ better climb rates at all altitudes, higher ceiling ... and was only a single speed engine.. and at 12lb boost, the numbers look even worse with 16lb. The P-40 was a generation behind in aerodynamics.

 

[Shortround6]

Historical P-40B, with 100 imp gals aboard, was performing as the SpitI/II/Bf-109E. The BoB fighters received the uprated engines and more weight, the P-40 received mostly more weight. The P-40D grossed at 7740 lbs clean, ie. 900 lbs more than P-40B, since it was now carrying 148 US gals of fuel (123 imp gals, 3 more than Spit VIII). The P-40E received 2 more HMGs ammo, with other models following suit. Clean it went to 8290 lbs.
The Spit V with 4 cannons was at 6917 lbs, the ones with 2 cannons were a tad lighter. Comparing it with P-40F (= 364.5 mph at 19,270) , it was some 7-10 mph faster, but RoC was way better for the lighter Spitfire.
The Bf-109 was both more powerful,lighter and smaller, while featuring improved aerodynamics vs. the 109E. No wonder it was able to outperform the P-40 easily.

In case the Merlin XX or 45 is mounted at the P-40B as-is, the weight difference will remain much closer, so the performance will be better. And the plane has much more internal fuel than SPit or 109, making it better for long range work.

And the P-40B had crap for armament. A P-40B had two .50 cal in the cowl (with waaaaay too much ammo) and four .30 cal in the wings. It could carry 160 US gallons total inside but the protection of the fuel tanks is doubtful, better than the earlier P-40s but not as good as the "C" Which had tanks that weighed 165lbs more while holding 25 gallons less. Perhaps only the wing tanks were protected?

A. can you fit synchronizers on the Merlin engine? or how much trouble is it?
B. can you keep the cowl mounted .50s with the higher thrust line of the Merlin engine? (prop raised about 6in over the needle nose P-40s)
C. Merlin is about 150-160lb heavier. Prop may be 50lbs heavier.

Of course if you ditch the fuselage .50 cals you can save 370lbs

BTW, "AHT" gives 7352lbs for a clean P-40B and that is with 114lbs of fuel in the rear tank and not the full 342lbs.

Unfortunately it doesn't really appear that the early planes were ALL that much lighter than the later ones considering the "stuff" added to the later ones. Even a "plain" P-40 (no letter) went 6807 lbs with 120 US gallons of fuel (100 imp gal) NO armor, No protected tanks, one .30 cal in each wing and 100lbs worth of .50 cal ammo (?) 166rpg (?) and minimal radio gear (60lbs less than E and up models). Filling the rear tank brought you to 7173lbs.

 

[oldcrowcv63]

Can't help but wonder about the performance of the 49th FG Base Fighter modified Group I II, P-40E (number 48) which was nearly 900 pounds lighter than the standard P-40E with 2 HMGs removed, reduced ammo to 190 RPG and carrying only 87 gallons of fuel with some wing tanks removed. Gross weight was in the vicinity of ~7,200 (according to the USAAF documentation) or ~7,400 lbs (if I assume Empty Weight was AHT's 6,070 lbs). Group III A/C had an additional ~350 lbs (!!!) removed (radio and other furnishings, armor???, SST???) reportedly had a maximum ceiling of 32,000 ft. Would a Merlin have been wasted on the Group I II A/C (or would it have been a game changer? With its 52 gallon belly drop tank, it would have much of the stock P-40E model's endurance restored. I think the Group III notion was discarded after one combat trial.

Late edit, added Useful Load for Group I II a/c: 1,348 lbs. above Empty Weight of either 5,861 lbs (USAAF doc) or 6,070 lbs (AHT).

 

[tomo pauk]

Waste of a good engine. A compatible Spit V against a P40F was 10-30mph faster at all altitudes, 500-1000fpm+ better climb rates at all altitudes, higher ceiling ... and was only a single speed engine.. and at 12lb boost, the numbers look even worse with 16lb. The P-40 was a generation behind in aerodynamics.

Don't know where to start from.
I've already stated/agreed that Spit V was 7-10 mph faster at ~20000 ft than P-40F. If the altitudes and engine power used is not stated, lumping the so-many-mph difference does mean nothing, least for aerodynamics comparison. The difference in supercharger is more of the academic point - it is the horse power what counts here. There is no much point in comparison of the RoC between a planes that were apart in weights by some 30%, on about the same HP - the fat P-40E grew another 450 lbs when 'became' the 'Merlin P-40'.
Again: stick the Merlin 45 in 6800-7600 lbs light P-40B (instead in the 8050-8300 lbs heavy P-40E) and then compare speed RoC vs. 6450 lbs Spit V. Further, install, in the Spitfire V, a protected tank (100-120 lbs?) for 35 imp gals (another 252 lbs; total ~6800 lbs now) and then compare performance.
If the P-40 was a generation behind in aerodynamics, how come P-40/P-40A/P-40B were as fast as Spit I and II above 15000 ft - despite ~50 HP deficit there, and bigger weight?

And the P-40B had crap for armament. A P-40B had two .50 cal in the cowl (with waaaaay too much ammo) and four .30 cal in the wings.

We're trying to envision a long range fighter, and that fighter will not need to kill bombers - that job is for interceptors mostly.
It's armament was far better than what most of pre-1944 Japanes fighter were carrying, it's not that much worse than what RAF used during the BoB, and it is certainly better than what Italian pre-5-series fighters had. For fighter-type targets of 1940-41, it was at least as good as what Bf-109E and 109F1/2 carried.

It could carry 160 US gallons total inside but the protection of the fuel tanks is doubtful, better than the earlier P-40s but not as good as the "C" Which had tanks that weighed 165lbs more while holding 25 gallons less. Perhaps only the wing tanks were protected?

Guess you're right here - the more/better/thicker protection, the less fuel is inside. The -C received drop tank capability, canceling out the loss of internal fuel.

A. can you fit synchronizers on the Merlin engine? or how much trouble is it?
B. can you keep the cowl mounted .50s with the higher thrust line of the Merlin engine? (prop raised about 6in over the needle nose P-40s)
C. Merlin is about 150-160lb heavier. Prop may be 50lbs heavier.

A, B - don't know; the HMGs might go into wings
C - Merlin XX - 125 lbs heavier than V-1710-C15. Merlin 45 (actually, 50M) - 60 lbs heavier (pg. 322, Vee's for victory; all numbers are dry weights).

Of course if you ditch the fuselage .50 cals you can save 370lbs

Not an option

BTW, "AHT" gives 7352lbs for a clean P-40B and that is with 114lbs of fuel in the rear tank and not the full 342lbs.

The P-40B, the test of which is available at Williams' site, is stated at 6835 lbs - the good deal might be a difference in ammo weight (what might be considered normal vs. maximum). The P-40 (no suffix) carried 165 lbs of ammo, vs. 345 lbs for the P-40B - 180 lbs differnce. But we still don't know where from the remaining ~350 lbs are emanating from.
This document states indeed 7326 lbs as 'normal gross weight' vs. 6835 lbs being 'design gross weight'. The 'normal fuel' was stated as 120 gals.

Unfortunately it doesn't really appear that the early planes were ALL that much lighter than the later ones considering the "stuff" added to the later ones. Even a "plain" P-40 (no letter) went 6807 lbs with 120 US gallons of fuel (100 imp gal) NO armor, No protected tanks, one .30 cal in each wing and 100lbs worth of .50 cal ammo (?) 166rpg (?) and minimal radio gear (60lbs less than E and up models). Filling the rear tank brought you to 7173lbs.

The stated 6835 lbs of weight indeed appear an overly optimistic figure for the P-40B, I admit. I've offered the greatest weight here, too, so the comparison is, hopefully, as realistic as possible.

 

[Shortround6]

We're trying to envision a long range fighter, and that fighter will not need to kill bombers - that job is for interceptors mostly.
It's armament was far better than what most of pre-1944 Japanes fighter were carrying, it's not that much worse than what RAF used during the BoB, and it is certainly better than what Italian pre-5-series fighters had. For fighter-type targets of 1940-41, it was at least as good as what Bf-109E and 109F1/2 carried.

Comparisons are hard because the American .50 cal had a truly dismal rate of fire when synchronized. Somewhere between 400-500rpm. A big reason why the US wanted to stick them out in the wing. The Japanese Ho-103 12.7mm fired at 900rpm until late in the war ( late war guns had a number of problems) and while that is the unsynchronized rate of fire their gun didn't suffer the big drop the American gun did, more like a 10-15% loss in rate of fire. While the Ki 43 carried crap for armament the KI 43 and Ki 61 with two Ho-103s and two 7.7mm mgs weren't that far behind the early P-40s. The Italian 12.7mm guns were supposed to cycle at 700rpms, actual synchronized rate??? Both Italians and Japanese used exploding bullets which ups the effectiveness of their ammo a bit. Perhaps the P-40s needed the extra wing guns a bit more? And are the two sllooww firing .50s really worth the 4 extra .303s the British planes carried?

A, B - don't know; the HMGs might go into wings
C - Merlin XX - 125 lbs heavier than V-1710-C15. Merlin 45 (actually, 50M) - 60 lbs heavier (pg. 322, Vee's for victory; all numbers are dry weights).

I have no idea why the Packard Merlin V-1650-1 weighs 60lbs more than than a British Merlin XX but it is there. Not a deal breaker. But 1510lbs vs 1350lbs (about ) for the V-1710-33. And the later P-40s used heavier propellers.

Not an option

Loosing 360-400 rounds of ammo should be (120lbs?) Fitting synchronizers to the Merlin is NOT impossible but not something you want to do in the field without factory support. A lot of times synchronizers were driven by the camshafts which means drilling a hole in the cam cover, fitting a mounting pad for the sychronizer and fitting the drive system to the end of the camshaft. A factory would design a different cam cover and just block off the the port/s for installations that didn't use synchronizers. And we still have the question of if the raised prop will clear the guns.

Fitting one .50 and one .30 in each wing might be a better option.

But you are designing with the benefit of hind sight. YOU KNOW both the Japanese and Italians dropped the ball when it came to better armament. You KNOW the Germans had problems with early 109F armament.

There is no reason (except production capacity) that the Ki 44 couldn't have had four 12.7mm mgs almost from the start. Same for the Ki 61. Germans had been fooling with engine mounted cannon since about 1936. Getting one that worked took until the 109F-4.

 

[tomo pauk]

Comparisons are hard because the American .50 cal had a truly dismal rate of fire when synchronized. Somewhere between 400-500rpm. A big reason why the US wanted to stick them out in the wing.

Well said.

The Japanese Ho-103 12.7mm fired at 900rpm until late in the war ( late war guns had a number of problems) and while that is the unsynchronized rate of fire their gun didn't suffer the big drop the American gun did, more like a 10-15% loss in rate of fire. While the Ki 43 carried crap for armament the KI 44 and Ki 61 with two Ho-103s and two 7.7mm mgs weren't that far behind the early P-40s. The Italian 12.7mm guns were supposed to cycle at 700rpms, actual synchronized rate??? Both Italians and Japanese used exploding bullets which ups the effectiveness of their ammo a bit. Perhaps the P-40s needed the extra wing guns a bit more? And are the two sllooww firing .50s really worth the 4 extra .303s the British planes carried?

It's "Ki-44 and Ki-61" you mean? Agreed, their main punch came from HMGs.
The British battery will score more hits once burst hits target, the P-40B might actually pierce some armor when the burst hits target - might help out negotiate the seat/head armor better, or armored widshield?

I have no idea why the Packard Merlin V-1650-1 weighs 60lbs more than than a British Merlin XX but it is there. Not a deal breaker. But 1510lbs vs 1350lbs (about ) for the V-1710-33. And the later P-40s used heavier propellers.

I've checked out the engine tables found in the AEHS. The V-1710-33 is at 1340 lbs there, vs. 1520 for the V-1650-1. The Merlin 45 is at 1385 lbs, I've checked 3 sources All dry weights.

Loosing 360-400 rounds of ammo should be (120lbs?) Fitting synchronizers to the Merlin is NOT impossible but not something you want to do in the field without factory support. A lot of times synchronizers were driven by the camshafts which means drilling a hole in the cam cover, fitting a mounting pad for the sychronizer and fitting the drive system to the end of the camshaft. A factory would design a different cam cover and just block off the the port/s for installations that didn't use synchronizers. And we still have the question of if the raised prop will clear the guns.
Fitting one .50 and one .30 in each wing might be a better option.

Yep, will save a bit of weight, while relocation of the HMGs will cancel out the firepower lost when a pair of LMGs is deleted.

But you are designing with the benefit of hind sight. YOU KNOW both the Japanese and Italians dropped the ball when it came to better armament. You KNOW the Germans had problems with early 109F armament.

If the fighter armament is tailored according to the perspective target, then hindsight is not needed - a fighter that will contest enemy fighters at enemy airspace will need lighter punch, than a fighter that will contest enemy bombers over own territory.
The Germans did not have problems with 109F-1/F-2, the 15mm cannon worked well.

There is no reason (except production capacity) that the Ki 44 couldn't have had four 12.7mm mgs almost from the start. Same for the Ki 61.

Agreed.

Germans had been fooling with engine mounted cannon since about 1936. Getting one that worked took until the 109F-4.

Until F-1?

 

[stona]

Yep, will save a bit of weight, while relocation of the HMGs will cancel out the firepower lost when a pair of LMGs is deleted.

Any evidence for that assertion?

The reasons for the RAF's eight gun armament were very carefully worked out in the mid thirties, both theoretically and experimentally. I very much doubt that Ralph Sorley would have agreed with your contention.

If you go with an interrupter system then you are also going to end up with different propellers on mid/late war fighters. It's one of the reasons that the Germans stuck with a three bladed propeller system.

The MG 151/15 did NOT work perfectly. Under certain flight conditions the belt jammed and blocked the ammunition feed. A temporary fix was made by front line armourers inserting small wooden blocks but the problem was never completely solved until the advent of the MG 151/20. You could say that the cannon armament worked reliably from about mid 1941.
I think rather more serious issues with wing skin wrinkling, wings coming off, empennages detaching at frame 9 and other problems with the elevators have somewhat overshadowed problems with the armament

Cheers

Steve