Maneuverability vs Speed

Wild_Bill_Kelso · Jun 21, 2023

Shortround6 said:
The OK for 1940 supercharger but failed to improve supercharger over the next 3 years.

Well except for the 3,000 two speed merlin ones they made in 1942 and 43

Shortround6 said:
Spitfire V used single speed supercharger and the Spitfire VI used a single speed, single stage supercharger (granted they didn't build very many of them)
The Spitfire VI had a pressure cabin, extend wings, 4 bladed prop, 364mph at 22,000ft and a service ceiling of 40,000ft. All with a single speed, single stage supercharger.

And how did the Spitfire VI perform at lower altitudes? Or the V for that matter? Superchargers, as you well know, could be tuned for different altitudes. With the Spit V they had the normal, LF with cropped impeller and (usually) cropped wings, and high altitude versions with the extended wingtips (which rolled like a Lancaster)

It was helpful to have a lighter airplane, but it didn't solve the need for an adjustable supercharger of some kind. As you well know.

Shortround6 said:
But Hooker was already working on the two speed, two stage supercharger.

There was no real magic about multi-speed superchargers. But they needed to be big enough to get the job done. Using a small impeller was not going to get the job done no matter how many speeds you used.

Correct.
Nobody else was trying to use an 8300-8500lb fighter with a 1150hp engine.

That is a bit of an exaggeration, as you probably are aware. And it weighed less than a P-51A with the same exact engine.

Shortround6 said:
Once it got above 12-13,000ft on the D-E-K s that is all the power you had,
and once of got above 17,000ft (in level flight) you had 1125-1150hp on the M & Ns.

http://www.wwiiaircraftperformance.org/P-40/A29-412-climb-WEP.jpg

This is for the stripped P-40N-1, 4 guns, no electric start, forward wing tank removed, etc.

you can put lipstick on a pig, The pig may be able to move pretty quick for a short distance. It is still a pig.

Except it wasn't 1150 hp at the lower altitudes, in fact it was over 1,500 hp

Which makes you wonder why that particular 'pig' was the 5th highest scoring US fighter, more than the F4U or F4F, more than the Spitfire in US use plus the P-39 combined.

Shortround6 · Jun 21, 2023

For the Zero in Europe thing.

The A6M2 held about 141 US gallons of fuel in internal tanks.

The Zero's secret was big drop tank (84-87 US gallons) and an absolutely miserly fuel burn at 180kts. 16.4 US gallons per hour.

Trouble is that at 190kts it went to 24.04 gph and at 200kts it went to 26.15gph. Still very good but with the tank gone and trying to cover hostile ground at much more than loiter speed you don't get anywhere near the ranges they got in the Pacific.

PAT303 · Jun 21, 2023

Shortround6 said:
Trouble is that at 190kts it went to 24.04 gph and at 200kts it went to 26.15gph. Still very good but with the tank gone and trying to cover hostile ground at much more than loiter speed you don't get anywhere near the ranges they got in the Pacific.

And with a 30 miles per hour deficit in top speed and unprotected fuel tanks getting chased by 8 gunned Spitfires loaded with very effect De Wilde ammunition is not going to be fun either.

Wild_Bill_Kelso · Jun 21, 2023

Shortround6 said:
For the Zero in Europe thing.

The A6M2 held about 141 US gallons of fuel in internal tanks.

The Zero's secret was big drop tank (84-87 US gallons) and an absolutely miserly fuel burn at 180kts. 16.4 US gallons per hour.

Trouble is that at 190kts it went to 24.04 gph and at 200kts it went to 26.15gph. Still very good but with the tank gone and trying to cover hostile ground at much more than loiter speed you don't get anywhere near the ranges they got in the Pacific.

Maybe not, but still much better range than any mark of Bf 109, MC 200, MC 202, Hurricane, or Spitfire, and definitely still better than a P-40. Not sure about a P-38.

The only even medium range fighter the Germans had in the Med was the Bf 110, and it wasn't that long legged (nor could it really handle fighting with most of the single-engined Allied fighters. If you had A6Ms stationed in Sicily or Crete I think those British convoys would have been in trouble. Even more so if you had some Japanese torpedo bombers.

On the Russian Front, on the Axis side, an A6M would be facing aircraft with poor high altitude performance that didn't normally loiter at high altitude, so if it needed to cover some distance I would think they could cruise at say, 18 or 20,000 ft at their best cruise speed, and speed up if needed (with a dive) if they saw enemy planes approaching. That is to some extent what they did in the Pacific.

On the Russian side (facing the Axis) they couldn't get away with that, but they would still have the considerable range advantage (2 or 3 times) over the Bf 109, and about twice that of a Fw 190.

I admit though, a Fw 190 would probably give an A6M2 or A6M3 serious trouble. A6M5 might be able to hold it's own though that is debatable.

Wild_Bill_Kelso · Jun 21, 2023

PAT303 said:
And with a 30 miles per hour deficit in top speed and unprotected fuel tanks getting chased by 8 gunned Spitfires loaded with very effect De Wilde ammunition is not going to be fun either.

I'm not convinced A6M was really outmatched by Spitfires until Mk VIII or IX. (I wouldn't say the other way around either mind you, Spit V could hold it's own with an A6M under normal conditions)

but also keep in mind in any tropical Theater, including the MTO, Spit V is going to be using those Vokes filters until (IIRC?) some time in 1943.

Shortround6 · Jun 21, 2023

Wild_Bill_Kelso said:
but also keep in mind in any tropical Theater, including the MTO, Spit V is going to be using those Vokes filters until (IIRC?) some time in 1943.

True but in any place except Australia the MK Vs were allowed to use 12-16lbs of boost depending on the date.

And a British test site got a Vb tropical up to 337mph at at 17,400ft with a loaded 90 imp gal drop tank underneath.
Without the drop tank they got 354mph.
And they were using only 9lbs of boost.

" This aircraft was fully tropicalised; this included an air cleaner installation whose fairing produced an external bulge beneath the nose, and tropical radiator and oil cooler installations. In addition various items of desert equipment were carried"

Spitfire Mk.VB (Tropical) AB.320 Report

SaparotRob · Jun 22, 2023

PAT303 said:
The P40 is the most underrated fighter of the war, as stated in another thread, it was the willys Jeep of fighters.

As well as its cousin across the pond, the Hurricane.

Wild_Bill_Kelso · Jun 22, 2023

Shortround6 said:
True but in any place except Australia the MK Vs were allowed to use 12-16lbs of boost depending on the date.

And a British test site got a Vb tropical up to 337mph at at 17,400ft with a loaded 90 imp gal drop tank underneath.
Without the drop tank they got 354mph.
And they were using only 9lbs of boost.

" This aircraft was fully tropicalised; this included an air cleaner installation whose fairing produced an external bulge beneath the nose, and tropical radiator and oil cooler installations. In addition various items of desert equipment were carried"

Spitfire Mk.VB (Tropical) AB.320 Report

354 mph is decent, and I think some marks of Spit V made better speed than that in North Africa. But so did P-40s and P-39s in the Pacific, and they were by no means guaranteed victory over an A6M or Ki-43. Nor was a P-51A even a P-38.

In North Africa, for comparison, P-40E made 345- 360 mph, P-40K made 350-360, P-40F made 360-370 mph, MC 202 made 360-372, Bf 109F made ~375-380 mph depending on who you believe and on filters etc., 109G2 and G4 maybe 375-385 mph, 109G6 ~405 mph. P-38G was making 404 mph

Only the P-38 and G-6 probably have enough of a speed advantage there to really have a marked advantage over a A6M, but only the P-38 could match it for range.

Shortround6 · Jun 22, 2023

Wild_Bill_Kelso said:
On the Russian Front, on the Axis side, an A6M would be facing aircraft with poor high altitude performance that didn't normally loiter at high altitude, so if it needed to cover some distance I would think they could cruise at say, 18 or 20,000 ft at their best cruise speed, and speed up if needed (with a dive) if they saw enemy planes approaching. That is to some extent what they did in the Pacific.

On the Russian side (facing the Axis) they couldn't get away with that, but they would still have the considerable range advantage (2 or 3 times) over the Bf 109, and about twice that of a Fw 190.

The Russian aircraft are not quite that bad. OK maybe the Lagg-3.
The Yak 1 & 7 are good for around 350-360mph at 5000meters or so. Which gives them a bit better capability at around 20,000ft than a P-40. They were a lot lighter (up to one ton lighter) Not being as good as the 109F is one thing, being as bad as a P-39/P-40 at altitude is something else.
An LA-5 in 1942 was supposed to be good for about 360mph at 20,000ft.
There were still Mig-3s around. 397mph at 25,500ft (OK perhaps 370-380 in service with part of the Canopy missing)

Soviet ranges are usually for rather high cruising speeds, Early Lagg-3s held about 124 US gallons of fuel which was estimated to be good for 438 miles (705km) at 0.9 of max speed.
I don't think they got it but that 0.9 cruising speed shows up a lot in Soviet descriptions. Might be too go to be true but the Soviets were definitely cruising faster than a lot of British- American planes. The Early Yaks were good for around 405-415 liters of fuel. These panes were not much bigger than a 109.

The A6M2 held about 536-537 liters of fuel internal, If you force them to run hard you are not going to get 3 times the range of 109, probably not even twice the range.
You have about 34% more internal fuel and the big drop tank, oh wait..................surprise, the Japanese tank is only 12% bigger than the German drop tank.

Basically the A6M2 has about 21% more fuel than 109 does if both have drop tanks.

Spindash64 · Jun 22, 2023

P-38 is admittedly a bit of a hard counter to the Zero: significant higher speed, excellent climb, comparable range… it even holds up surprisingly well against the Zero in horizontal maneuvering. Obviously the Zero has a far lower stall speed, but with Fowler Flaps deployed, the 38's Power OFF stall drops to 86mph Calibrated. Power on stall speed is significantly lower for the P-38 relative to the difference in other fighters, due to greater wing area effected by propwash. In addition, the lack of net torque combined with its benign stalls means it is in less danger of losing control at very low speeds.

It would still be incredibly foolish for a P-38 pilot to play the Zero's game, but if the 38 got lucky enough to end the fight quickly, there's a nonzero chance of him getting away with it

Shortround6 · Jun 22, 2023

Wild_Bill_Kelso said:
354 mph is decent, and I think some marks of Spit V made better speed than that in North Africa. But so did P-40s and P-39s in the Pacific, and they were by no means guaranteed victory over an A6M or Ki-43. Nor was a P-51A even a P-38.

There are no Guarantees, There are only improved odds. And the A6M2 in many places around the globe did not have good odds or at least not the odds they enjoyed in early 1942 vs the Allies in the the SW Pacific/Asia.

It also not just about speed. Spitfires had much better climb than the American planes. More power/Less weight.
If gives the Spitfire options that the P-40 did not have. Spitfire still should not get into a turning fight with Zero.

PAT303 · Jun 22, 2023

Wild_Bill_Kelso said:
I'm not convinced A6M was really outmatched by Spitfires until Mk VIII or IX. (I wouldn't say the other way around either mind you, Spit V could hold it's own with an A6M under normal conditions)

As SR posted earlier a 1940 MkII is a very different animal to a 1942 Darwin MkV.

PAT303 · Jun 22, 2023

Shortround6 said:
Spitfire still should not get into a turning fight with Zero.

Below 200mph like every other aircraft, stay above that and especially above 250mph and the Zero loses it's trump card.

Reluctant Poster · Jun 22, 2023

Wild_Bill_Kelso said:
I am well aware, but how many day-fighters were accompanying RAF Bomber Command on their raids?

You are defining air combat as day fighters which a very narrow view.

Reluctant Poster · Jun 22, 2023

GregP said:
If someone is going to bomb your city (or base, etc.) and you have limited warning time, the ROC is more important than fuel. If you can't get to the enemy, he will bomb his target. If you CAN get to your enemy, then getting there with more fuel is the best option, assuming enough ammunition to make a difference.

So, ROC doesn't take a back seat to more fuel unless you can get to altitude in time to stop the bombing attack. If you can't get there in time, all the fuel and / or ammo doesn't count, at least for that particular attack.

I would also add that radar systems of WWII had difficultly in determining altitude. There are several examples in the carrier battles of 1942 of F4Fs patrolling at the wrong altitude and being unable to intercept due to their sluggish rate of climb.

Reluctant Poster · Jun 22, 2023

GregP said:
Yeah, that's max speed with the engine about to explode ... at WER. Hardly anyone used that as a regular matter of course. If they did so frequently, they were likely a POW soon thereafter. WER was saved for really bad circumstances, when you needed to escape.

Again, a quote from a real WWII pilot, "WER was for test pilots over the home airfield and company sales pitches."

I am curious as to the use of WER by RAF pilots on V-1 duty. Speed is paramount and you are over friendly territory. Does anyone have data on Merlin and Sabre engine life for that duty.

GregP · Jun 22, 2023

Elvis said:
Roll rate alone doesn't neccessarily make for a fighter with the agility of a Zero.
Look at the P-40. Superior roll rate to a lot of fighters, and yet NO ONE hails its agility as a fighter. Most just seem to harp on it being an overweight turd that couldn't fight its way out of a paper bag.

Yet it is judged as about even with the Bf 109 at under 12,000 feet by almost all who flew it.

GregP · Jun 22, 2023

PAT303 said:
Sorry but I disagree, the British could see the bombers forming up before they crossed the channel, they also tracked them right across into British airspace before scrambling the fighters at the last minute because they didn't have the fuel to do otherwise resulting in them almost always climbing up from underneath, numerous BoB pilots have stated this, with another 30G tank behind the seat the fighters could have launched earlier and been at altitude before the bombers crossed the channel or had time to climb higher still to engage the top fighter cover, not just that with another 20 minutes of fuel the fighters could have been vectored to better positions to attack instead of straight up, lastly the extra fuel wouldn't inhibit the fighting qualities of the Spitfire because it would be gone before entering combat, just like any other fighter with aux or drop tanks. The only time a fighter has too much fuel on board is if it's on fire.

First, it's OK to disagree.

Perhaps you've never been to the UK. In the summer there are some nice days. But there are all too many during which you cannot see very far across the channel due to weather. When I was there, I could see well across the channel less than than 1/3 of the time when we wanted to see the channel. Now, I don't have the weather reports from the Battle of Britain timeframe, but I'd bet you couldn't count on seeing enemy bombers from very far away since it was IFR a good slice of the time. The ETO was largely an IFR theater of operations, especially in fall and winter.

I've never seen a report saying the British were short on fuel during the BOB. In fact, they introduced 100-octane fuel at that time. It increased the top speed of the fighters by some 20-30 mph at altitude, and everyone was happy about that.

Thumpalumpacus · Jun 22, 2023

GregP said:
See, what did I tell you ...

And, actually, it depends on what your objective is. If someone starts a war, your objective is to either win or get him/her to the peace table and talking. If you get the upper hand then, by all means, go ahead and win. If you don't, your objective usually shifts to the peace table to get the war to stop when it starts going badly for your civil population.

You know the difference between a single and a home run? It's in the follow-through.

If one has the upper hand and doesn't follow through, one is doing a criminal disservice to those who are doing the fighting and dying. A real-world example is the German decision at Dunkirk to halt pursuit.

Wild_Bill_Kelso · Jun 22, 2023

Reluctant Poster said:
You are defining air combat as day fighters which a very narrow view.

No, it's just that we were discussing day fighters. Night fighters are a very different context, and usually, different aircraft too (typically though not always twin engine aircraft). Maneuverability isn't so much of an issue with nighttime air combat either.

Maneuverability vs Speed

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