Maneuverability vs Speed

[cherry blossom]

At least until there were bases established between Rabaul and Guadalcanal, it has been argued that Zeros often entered combat over Guadalcanal without dropping their drop tanks Zero Model 21 Performance: Unraveling Conflicting Data. This may partially explain why the A6M2 was not as successful over Guadalcanal as might have been expected from its performance.

 

[GregP]

In truth they were all after it all. faster, better rate of roll, turn and climb. The Zero was agile because it was light, it was light to give it a huge range. The Spitfire had a good rate of turn because it had a good rate of climb. All sorts of things were done to the Spitfire improve rate of roll throughout its service ending up with completely different wings. Same for the P-51 and especially the P-38 with powered ailerons etc.

Rate of turn has very little to do with rate of climb. The only thing that links rate of climb to turn at all is excess power, which is need to sustain a steep turn. The rate of turn depends in airspeed and bank angle, but you need sufficient lift and excess power to sustain a level turn if that is your aim. So, while the rate of turn depends on arispeed and bank angle, it assumes sufficient lift and power are available. If not, you will descend while turning (insufficient power) or stall (insufficient lift).

 

[cherry blossom]

Although there is a general agreement in this thread that performance trumps manoeuvrability, defeating more manoeuvrable fighters could be difficult. I found some (translated) comments from Johannes Steinhoff at Johannes Steinhoff – First Aero Squadron Foundation ™ on fighting against Yak-9s:

"I passed one that looked as if it was hanging motionless in the air (I am too fast!). The one above me went into a steep right-hand turn, his pale blue underside standing out against the purple sky. Another banked right in front of the Me's nose. Violent jolt as I flew through his airscrew eddies. Maybe a wing's length away. That one in the gentle left-hand curve! Swing her round. I was coming from underneath, eye glued to the sight (pull her tighter!). A throbbing in the wings as my cannon pounded briefly. Missed him. Way behind his tail. It was exasperating. I would never be able to shoot one down like this. They were like a sack of fleas. A prick of doubt: is this really such a good fighter? Could one in fact, successfully attack a group of erratically banking fighters with the Me 262?"

 

[PAT303]

Never saw that one anywhere in print. Doesn't mean it isn't, I just never saw that written anywhere. They were observed to do that (nose over to escape) on numerous occasions.

Galland was outmaneuvered by Spitfires on at least two occasions causing him to both run out of fuel plus he climbed vertically as steep as he could and fired his guns hoping the smoke from the exhaust and guns plus showering the pursuing Spit in empty casings would persuade it to give up, I don't know his name but one of the leaders of JG26 also mentioned he didn't like it in JG26's biography because of the reasons explained, what you do read about in everything air combat was the split S.

 

[PAT303]

I haven't read that anywhere. I am a pilot and have done that maneuver many times and it is actually quite fun. Akin to a roller coaster drop.

Not at 400+mph in a 109 though

 

[Gary Cain]

Not at 400mph in a 109 were your head touches the canopy in normal flight though

The pilot is well strapped in in a 109, his head can't hit the canopy unless he was rather tall, which would be a rarity. Rall was a good friend, he never mentioned anything that you claim.

So, un named sources, vs the 3rd highest scoring Ace in the world.

 

[PAT303]

If a Bf 109 bunts into a nose over the RAF have just had a tactical victory, the bombers are still up "there" and he isnt.

This is my opinion so take it as such, I think the 109 pilots did bunt over, a more accurate term but only at the very start before rolling into a split S, from a pursuing Spit/Hurricane it would look like a negative G dive as they shot past, like I said my opinion reading pilots notes/reports.

 

[PAT303]

The pilot is well strapped in in a 109, his head can't hit the canopy unless he was rather tall, which would be a rarity. Rall was a good friend, he never mentioned anything that you claim.

So, un named sources, vs the 3rd highest scoring Ace in the world.

Watch from 5:40, the British pilots head is level with the top windscreen frame and he is a small man, the German pilot is larger but look at how much room he has in the Spitfire.

 

[JoblinTheGoblin]

Although there is a general agreement in this thread that performance trumps maneuverability, defeating more maneuverable fighters could be difficult...

It seems that this might have been a key factor in the initial preference for maneuverability that the Japanese had prior to Pearl Harbor, with fast designs such as the Ki-28 rejected in favor of nimbler designs like the Ki-27, a preference bolstered by the experiences of pilots over China. The Japanese just seemed to be 3-5 years, at best, behind the designs of other powers in terms of speed, with the main weakness being engine power. Even the smaller economy of Italy was able to produce the overpoweringly fast Macchi M.C.72 in 1931, with indigenous engine design, albeit with two engines mated together, with a configuration similar to that of the still slower, non-indigenous-engined failure that was the Ki-64, which flew over a decade later. The closest Japanese aircraft with Japanese engines in terms of speed, recorded speed anyways, was the twin-engined Ki-83; I'm unsure about the veracity of the >750km/h speed that has been mentioned on occasion, and of the speeds of late-war aircraft like the Ki-87. On a side note, I've noticed that there is quite a number of Japanese aircraft close to, above, or below 580km/h in terms of maximum airspeed, a bit of an oddity I've noticed (Ki-61-I, Ki-100, Ki-44-I, N1K1-J, Ki-102b, as examples). All this doesn't speak well to Imperial Japan's industrial capacity and self-sufficiency, and calls into question its status as a major power of the time.

I've heard multiple reasons as to why Japanese engines were smaller and weaker. Manufacturer fears of disrupted supply chains due to Allied bombings (one would think that deadlier and more protected aircraft might just have mitigated this ultimately self-imposed existential threat, even if only slightly) is one peculiar reason; weaker industry seems to be an obvious problem, though to what extent? I've read that the lower numbers of skilled mechanics was a factor, with manufacturers generally preferring for simpler and less advanced designs. Inferior metallurgy, if I recall correctly, has also been mentioned in the past as a possible reason. Inferior chemistry, lack of high-octane fuel and lack of a good fuel mixture? The Ta-152's performance did seem to have increased greatly with a nitrous oxide injection, from a cursory search. Any other noteworthy reason?

I mainly bring all this up because I've heard extremely optimistic descriptions of the Imperial Japanese aviation industry, like the Aviation Geek Club, or some other similar website (I couldn't find the article as of posting this), which claimed that Japanese aircraft were unmatched in the world, based on, though not explicitly, Japanese tests involving foreign aircraft, which were typically models years out of date, and possibly in questionable condition.

Pardon the rambling. I am hard-pressed to find a proper resource anywhere online on Japanese aircraft performance, especially in English. At times, it feels like most of the discussion of WWII technology is centered on the war in Europe, or in the case of the Pacific War, the A6M or kamikaze, which I'm (almost) sick of seeing or hearing about at this point.

 

[BarnOwlLover]

Russia also favored smaller, "more traditional" fighters until the jet age, because Soviet industry didn't have the tech to make a really good 1500+hp engine, the Shvetsov M-82 not withstanding (even that was based on the Wright R-1820 Cyclone as far as heritage). Even the Klimov M-105 wasn't insanely reliable, especially in later versions due to being an outdated design (based on the Hispano-Suiza 12Y family), and it only made over 1300bhp. And the Mikulin AM-42 made over 2000 hp, but was only good for the Il-10 ground attack/close support aircraft (and that engine was cobbled together from a BMW VI-based engine block, reduction gear from a Rolls-Royce Buzzard and a supercharger taken design-wise from the Allison V-1710). Turbocharged versions were made for the MiG I-220 series fighters, but the turbos were unreliable.

The Soviets had the talent to design aircraft competitive with the US, England or Germany, but not the industry infrastructure or access to high grade materials until after the war. It can be argued that Japan to a degree had the same issue. Not to mention that Germany was stuck using 87 octane fuel for most of World War II. Stating that for reference, given that I've read here that 87 octane was "the good stuff" for Japan and Italy for much of World War II.

 

[GregP]

Galland was outmaneuvered by Spitfires on at least two occasions causing him to both run out of fuel plus he climbed vertically as steep as he could and fired his guns hoping the smoke from the exhaust and guns plus showering the pursuing Spit in empty casings would persuade it to give up, I don't know his name but one of the leaders of JG26 also mentioned he didn't like it in JG26's biography because of the reasons explained, what you do read about in everything air combat was the split S.

Never said everyone nosed over to avoid getting shot down.

I said many used the nose over as well documented and I never heard anyone say or saw in print they were uncomfortable with nosing over.

When I got my private license, I practiced nosing over in case of power failure on climbout. It wasn't exactly a tough or uncomfortable maneuver in a C-172 or a Cherokee. Of course, the only way to get either of them to 400 mph might to lose the wings going straight down. Even then, you might not get to 400 mph.

Cheers.

 

[GregP]

Not at 400+mph in a 109 though

He also never claimed that?

 

[GregP]

Although there is a general agreement in this thread that performance trumps manoeuvrability, defeating more manoeuvrable fighters could be difficult. I found some (translated) comments from Johannes Steinhoff at Johannes Steinhoff – First Aero Squadron Foundation ™ on fighting against Yak-9s:

"I passed one that looked as if it was hanging motionless in the air (I am too fast!). The one above me went into a steep right-hand turn, his pale blue underside standing out against the purple sky. Another banked right in front of the Me's nose. Violent jolt as I flew through his airscrew eddies. Maybe a wing's length away. That one in the gentle left-hand curve! Swing her round. I was coming from underneath, eye glued to the sight (pull her tighter!). A throbbing in the wings as my cannon pounded briefly. Missed him. Way behind his tail. It was exasperating. I would never be able to shoot one down like this. They were like a sack of fleas. A prick of doubt: is this really such a good fighter? Could one in fact, successfully attack a group of erratically banking fighters with the Me 262?"

What exactly do you mean "performance?"

Maneuverability generally means a tighter turn or lower 360° turn time.

But, to my thinking, acceleration, rate of climb, rate of roll, and armament data are also "performance." If you have a powerful fighter that climbs, rolls, turns, and shoots better than another one that is slightly faster at top speed, I'd take it any day. Top speed is generally WAY overrated. The veterans I have spoken with told me they never got to top speed except in a dive from altitude. The rest of the time they were cruising, climbing, descending or, if in combat, turning kept them from ever getting to top speed ... which is only achieved in a straight line after some acceleration.

Maneuvering envelope, airframe strength, etc. are all part of "performance." Top speed is only one item of about six or so in "performance." Add another one if you include cockpit ergonomics that make the pilot more comfortable in combat. Add another one if you include better visibility.

 

[BiffF15]

The pilot is well strapped in in a 109, his head can't hit the canopy unless he was rather tall, which would be a rarity. Rall was a good friend, he never mentioned anything that you claim.

So, un named sources, vs the 3rd highest scoring Ace in the world.

Gary / Gents,

A well strapped in pilot is not the same as being bolted down. I strapped into the Eagle as tight as I possibly could (not a fan of negative G'), and when pushing forward on the stick or doing a big unload (zero to negative G's) the straps will bite into you lap resulting in you coming out of the seat and hitting the canopy if there isn't enough room. I would also raise my left arm and push against the canopy when doing some maneuvers to keep me planted.

If you talk with guys who flew single seat Eagles they will probably never bring it up, but you will get bruises on your elbows and right bicep from the jet and your harness. Those things are really background noise in the big picture and are rarely mentioned. Also some guys don't like negative flight and therefore avoid it, and Rall may have been one of those guys. I disliked it but used it when necessary.

If you talk with guys who flew carburetored aircraft, it doesn't take much to make the motor cut out. In a dogfight it doesn't take much, but an edge is an edge if it helps you get out of trouble. Guys spoke of being able to tell when an attacker could shoot them or not. It is an acquired skill, and it consists of recognizing when a guy is in range, in plane (where his nose is pointed relative to your flight path), and in lead. Once you get good at that it's a difficult target you become, especially with altitude below you.

Cheers,
Biff

 

[Just Schmidt]

I don't agree that Japanese fighters, at best, were 3 to 5 years behind in speed. From memory:
1940 A6M ca. 530 km/h
1941 Ki 44 I ca. 580 km/h
1942 Ki 61 I ca. 590 km/h
1943 Ki 44 II ca. 605 km/h
1944 Ki 84 I ca. 635 km/h

This seem to be official Japanese figures. Somewhere on the forum there are posts indicating the Japanese measured top speed differently than the allies.

They certainly were behind in engine development, and design philosophy did initially sacrifice a lot for manouverability.

It is remarkable that they introduced the 580 km/h Ki 100 in 1945, but that arose from special circumstances. The coincidence of many being in the 580 to 600 range probably is just that, and it was ( slightly) exceeded already in 1943. Few fighters in the world exceeded 600 before 1942.

That said, Japan certainly was at the lower end of major powers, considering their population and industrial base. But I'm m not sure how to draw the line between major and midling. Considering what they had to work with, I don't think they did that poorly. The did make serious mistakes, as did all the combatants, some were just better able to afford them.

 

[tomo pauk]

Pardon the rambling. I am hard-pressed to find a proper resource anywhere online on Japanese aircraft performance, especially in English

You can take a look in this forum, there is a lot of topics covering japanese aircraft, and many contemporary docs can be found, as well as Allied flight tests and assessments.
Here is also a lot of data: WWII Aircraft Performance

Russia also favored smaller, "more traditional" fighters until the jet age, because Soviet industry didn't have the tech to make a really good 1500+hp engine, the Shvetsov M-82 not withstanding (even that was based on the Wright R-1820 Cyclone as far as heritage).

Why should we discard the M-82? Or AM-38 for that matter?

And the Mikulin AM-42 made over 2000 hp, but was only good for the Il-10 ground attack/close support aircraft (and that engine was cobbled together from a BMW VI-based engine block, reduction gear from a Rolls-Royce Buzzard and a supercharger taken design-wise from the Allison V-1710).

Woah.
Any sources that confirm that AM-42 was a cobbled-together engine with prevailing foreign bits and pieces?

 

[Wild_Bill_Kelso]

Defining maneuverability is potentially a quite useful concept, but very tricky. 20th Century books on military aviation constantly use that term and it was not always clear what was meant. In fact it was often quite misleading.

Personally, I don't think it just boiled down only to turning radius. It's a bit slippery of a concept and does bleed over into 'performance', another rather broad term that is often used. But generally I'd say maneuverability at a minimum means both turn radius and roll rate. I think climb and dive and come into it as well.

In the case of the Zero for example, one particularly lethal technique they had was done if their opponent tried to make a loop, the A6M could climb at a very steep angle loop inside them and shoot right into the cockpit with their nose guns, often killing the pilot (from that angle there was no armor protection). This was a standard technique they used.

H.J. Marseille used to do something similar with Bf 109Fs in North Africa, climbing or diving very steeply to attack - shoot right into the cockpit from above or below. He killed many Allied pilots this way, though most of the other German pilots including the 'experten' said that few could match this technique.

Another more common tactic used by the Finns and the Germans involved a flight of four aircraft splitting into two pairs, each making a climbing turn in the opposite direction. The Soviet fighters lacked the performance to keep up in this turn and would start to lose power or 'E', and would often select one of the two pairs to attack while ignoring the other. The 'free' pair would come up behind the Soviet fighters and shoot them down just as they were concentrating on pulling lead.

In their assessments of aircraft it is notable that the Soviets distinguished between 'vertical' and 'horizontal' turning ability.

When it comes to rolling, turning and diving there are also different measures, which makes quantification tricky.

There is instantaneous and sustained turning.
Medium and low speed turning
Vertical and horizontal turning (if we can borrow the Soviet concept)
Turning with and without partial flaps (some aircraft had specific turn settings for the flaps, or even automatically deploying flaps)
Turning with and without leading edge slats
Maximum climb rate (often at very low speed, unsuitable for combat), climb angle, and (shallow or steeper) climb speed.
Dive acceleration and maximum dive speed.
Maximum possible roll, roll at 30 or 60 lbs force, roll acceleration etc. Some aircraft had boosted ailerons (late model P-38s for example). Roll reversal.

If we could find a way to quantify all these things it could really help make sense of maneuverability.

 

[Wild_Bill_Kelso]

In combat, 'maneuverability', however that is defined precisely, could be used to catch enemy planes (what they would say today as arrive at a shooting solution), to evade enemy planes, and in some cases, to disengage. The same is also true for performance including maximum speed, acceleration, dive and climb.

There is also the factor of handling. Some aircraft were maneuverable in one way or another, but had tricky handling. Others which maybe did not have as good of a turn or roll rate, had better handling (in the sense of, being easier to control without going into a spin or a stall) and as a result were more often pushed to their limits, thus gaining better performance.

I think this was a factor with the P-39, American pilots generally trusting it far less than Soviets, who I think had more experience with 'twitchy' aircraft like the I-16.

Another related factor is structural strength. When pulling high G loads, there is always a risk of structural damage or even catastrophic failure. I have read that some Spitfire and Hurricane pilots during the early war did not pull G in turns because they weren't sure how far they could get away with it. This is another thing where training can come into play. On the flipside of that, some aircraft were too flimsy for hard turns and could collapse or disintegrate during turns or dive pullouts. Many aircraft took sets to their wings and were therefore considered 'war weary' and were scrapped for parts (or sent to the Soviets, rather cynically).

 

[Wild_Bill_Kelso]

Another factor is high speed control, such as ailerons tightening, and the presence or lack of trim tabs to help deal with this. Both the Bf 109 and the A6M had some problems with control tightening at higher speeds and combined with the effects of torque, meant turning was only possible in one direction at higher speeds, something which was eventually discovered and exploited by Allied pilots.

 

[BarnOwlLover]

You can take a look in this forum, there is a lot of topics covering japanese aircraft, and many contemporary docs can be found, as well as Allied flight tests and assessments.
Here is also a lot of data: WWII Aircraft Performance



Why should we discard the M-82? Or AM-38 for that matter?



Woah.
Any sources that confirm that AM-42 was a cobbled-together engine with prevailing foreign bits and pieces?

The AM34 (and later versions) were based on the M17, which was a license built BMW V1 V12. Development did remove it from it's origins (just like the Klimov M100s Shevestov radials diverged from the H-S 12Y and Wright Cyclone respectively), but it was still the starting point. Not to mention an AM42 taken from an Il-10 that was being restored showed the supercharger assembly, which looks like it was cribbed directly (design-wise) from a single stage Allison.

Most Soviet engine tech, even into the early jet era, was often based on foreign designs that were licensed (or copied in the case of the captured German engines) Even the MiG-15 and MiG-17's Klimov VK-1 engines were based on the Rolls-Royce Nene.

There were attempts to adapt the AM42 to the MiG I-220s using a turbocharger to back up the single stage supercharger for improved altitude performance, but the turbo was very unreliable. The Russian's could've had their own P-51 Mustang if they got the turbo to work, or were able to adapt the AM42 to use a two stage supercharger.

Why the M82 as a fighter engine shouldn't be counted is that it was a 1500+ hp capable engine from the start, and later versions could make over 2000 hp under WEP/take off power (though 1850 was the most common rating for like the La-7/9/11). The AM38 was a 1600-1700+hp capable, but at low altitudes (it was the main engine used in the Il-2), and aside from the MiG fighters, no other fighter could use them because of the engine's size and weight. You can't really shoehorn an engine the size and weight of a Rolls-Royce Griffon or Jumo 213 or DB603 into a plane designed for basically a HS 12Y derivative. The racing P-51s Red Baron and Precious Metal used R-R Giffons from Avro Shakelton patrol aircraft, but those were single stage engines, not two stage like most Griffons. Hence, those engines were shorter and lighter than say a Griffon from a Spitfire.

As far as say the Yakovlev fighters, though a Yak-7 prototype was fitted with a M82, as well as a Yak-3 prototype post war, most stuck with the Klimov M105 and later M107 engines. The M105 in its late versions were pushing it in terms of durability and reliability, and the M107s were never particularity reliable. I'd say it's a toss up between the M107 and the Allison V-1710s out of F-82 Twin Mustangs as far as which was better or worse.