The Zero's Maneuverability (1 Viewer)

[MIflyer]

Recently I ran across an issue of Flight Journal that has an article in it by Corky Meyer, the WW2 Grumman test pilot, describing his observations when he flew a captured Mitsubishi A6M5 Type 52A in October 1944 at the famous Joint Services Fighter Conference.

He considered the Zero to be very easy to fly, with especially good stall characteristics, the stall being 20 kts lower than American fighters and with no tendency to drop a wing. Its best climb speed was 20 kts lower than the Hellcat and he was amazed that he could not only pull a tight loop but actually gain altitude in the process, even when starting the loop at only 120 kts. With a 120 kt entry speed the Zero could end the loop 1200 ft higher than it started. A Wildcat has a minimum loop entry speed off 160 kts and would lose several hundred feet by the end of the loop.

He found the cockpit to be very comfortable with excellent visibility, with the seat able to be raised so that the pilot's head protruded over the canopy for great visibility during taxiing. There good locations for the instruments, even though he is 6 ft 3 inches tall, although the rudder pedals were too close in to be very comfortable.

The controls were smooth and well balanced at lower speeds but at above 240 kts (275 mph) both the ailerons and elevator were as if they were "set in concrete." In contrast the rudder was if anything too light, even at higher speeds. The official US tests showed that the ailerons got heavy above 200 kts, and obviously 240 kts was an even worse condition.

The Model 52A had a maximum dive speed of only 355 kts. The Wildcat had a max dive speed of 400 kts, the F6F-3 dive limit was 420 kts and the F6F-5 was 455 kts. The A6M5C featured thicker wing skins that increased the max dive speed to 400 kts. But Corky points out it is hard to see how the increased dive speed would do much good if the controls were still all but immovable above 240 kts.

In contrast, looking at the RAF tests of the Brewster Buffalo, the ailerons were judged to be crisp, powerful, and effective up to 400 MPH, better than the Spitfire and Hurricane. The elevator was also tested at up to 400 MPH and also was found to be effective, as was the rudder. While it did drop a wing in a stall, it unstalled very quickly.

The rather obvious conclusion is that if the Buffalo had been equipped with the 1350 HP R-1820 that was fitted to the FM-2 and the B-17G and the pilot had been careful to stay above 250 mph the Zero would not have been able to dominate the Buffalo so easily.

 

[marathag]

But Corky points out it is hard to see how the increased dive speed would do much good if the controls were still all but immovable above 240 kts.

I believe aileron effectiveness was reduced after the A6M1 so not to twist up the lightly built wing. Stronger wings would alleviate that

 

[cherry blossom]

I tried to find that story about two years ago Mitsubishi A6M Reisen balance tabs but I am still waiting for some Japanese reading expert to give me the details.

 

[PAT303]

I find all these comparisons pointless because the design of western aircraft was set to meet the different philosophies of western fighting, the RAF USAF could have made their version of the A6M but they considered that design approach wrong, and history shows that they were right.

 

[MIflyer]

I believe aileron effectiveness was reduced after the A6M1 so not to twist up the lightly built wing.

I have heard that, too. Another thing mentioned by Corky was that when they first pulled it out of the hangar it was making "tin canning" type noises. The USN officer in charge of the Zero said that when it warmed up in the Sun those noises would go away.

My Ercoupe is not what you would call heavily built but it does not make tin canning noises when it is sitting there cold.

 

[Juha3]

I find all these comparisons pointless because the design of western aircraft was set to meet the different philosophies of western fighting, the RAF USAF could have made their version of the A6M but they considered that design approach wrong, and history shows that they were right.

Was it so simple. Zero and Ki-43 designs put too much emphasies to lower speed manoeuvrability but look Grumman F8F Bearcat, light structure to allow excellent vertical manoeuvrability. And A6M's very long range single engine fighter with capacity to fight enemy fighters with equal terms, something e.g. the USAAF found to be an important asset.

 

[PAT303]

Was it so simple. Zero and Ki-43 designs put too much emphasies to lower speed manoeuvrability but look Grumman F8F Bearcat, light structure to allow excellent vertical manoeuvrability. And A6M's very long range single engine fighter with capacity to fight enemy fighters with equal terms, something e.g. the USAAF found to be an important asset.

It was simple, the A6M was made as light as possible allowing nimble handling and long range, to the detriment of pilot protection and aircraft survivability. The RAF USAF Luftwaffe aircraft design emphasised pilot protection, communication, airframe robustness with hitting power of their weapons as priority. Supermarine could have stripped the Spitfire likewise Grumman the Wildcat of all armor, self sealing tanks, bullet proof windscreen, radio, IFF equipment plus anything else that inhibits maneuverability and used the weight saving to carry more fuel but the BoB for instance would have not ended the way it did if they decided to follow that route.

 

[SaparotRob]

Different times, different missions. The Zero was maximized for range. The Pacific is big. The U.S. is big. The USAAC had to have longer ranged planes than anyone else needed just to get from one end of Texas to the other. That had to be a major influence of Japanese and U.S. inter-war designs. The nature of the war changes. The F8F was a newcomer. Why would the U.S. even bother with yet another production line, supply chain and more blue paint? What did the F8F bring to the table that the Hellcat and Corsair couldn't do? Climb really fast to intercept kamikazes. Kamikazes weren't on anyones radar in 1941. I know the F8F was real bear of a plane but for escort, reconnaissance, strike missions, the other two were good enough. It could get off the flight deck and climb to intercept kamikaze swarms. IMHO the F8F is kind of a niche airplane.

 

[Thumpalumpacus]

I tried to find that story about two years ago Mitsubishi A6M Reisen balance tabs but I am still waiting for some Japanese reading expert to give me the details.

Paging Shinpachi , maybe he can help you?

 

[GregP]

Don't think the F8F was ever intended for escort.

It was simple, the A6M was made as light as possible allowing nimble handling and long range, to the detriment of pilot protection and aircraft survivability. The RAF USAF Luftwaffe aircraft design emphasised pilot protection, communication, airframe robustness with hitting power of their weapons as priority. Supermarine could have stripped the Spitfire likewise Grumman the Wildcat of all armor, self sealing tanks, bullet proof windscreen, radio, IFF equipment plus anything else that inhibits maneuverability and used the weight saving to carry more fuel but the BoB for instance would have not ended the way it did if they decided to follow that route.

According to the original designer, Jiro Horikoshi, the weight was not "as light as possible." The weight was set by the power to weight ratio desired and the available horsepower anticipated from the engines that were envisioned for service. The Zero never had more than just under 1,200 hp and performed very well for a military aircraft of that power level. The Zero started life with 780 hp (Zuisei 13) and 1,000 was anticipated. They weren't far off as 940 (Sakae 12) 1,130 hp (Sakae 21 and 31) was the max used in the A6M series up until the A6M8. It's hard to credit the 1,560 hp A6M8 with anything since they only made and flew 2 prototypes that never saw combat.

 

[MIflyer]

Well, the US did build lightweight fighters that had little or no armor. We just did not produce them in large numbers. And that P-66 sure looks like a Zero.

However, as the article from Corky shows, building an airplane that was lightweight and did not use armor did not simply leave the pilots at risk. Such an approach also placed additional restrictions on the aircraft. The Zero was nimble but at speeds over 220 Kts it was almost a sitting duck, neither able to roll into a turn quickly nor flip into a climb or a dive.

 

[PAT303]

Don't think the F8F was ever intended for escort.

According to the original designer, Jiro Horikoshi, the weight was not "as light as possible." The weight was set by the power to weight ratio desired and the available horsepower anticipated from the engines that were envisioned for service. The Zero never had more than just under 1,200 hp and performed very well for a military aircraft of that power level. The Zero started life with 780 hp (Zuisei 13) and 1,000 was anticipated. They weren't far off as 940 *Sakae 12) 1,130 hp (Sakae 21 and 31) was the max used in the A6M series up until the A6M8. It's hard to credit the 1,560 hp A6M8 with anything since they only made and flew 2 prototypes that never saw combat.

So having the overall weight dictated by only have a max of 1200hp didn't put emphasis on the aircraft to be as light as possible?

 

[PAT303]

Well, the US did build lightweight fighters that had little or no armor. We just did not produce them in large numbers. And that P-66 sure looks like a Zero.

However, as the article from Corky shows, building an airplane that was lightweight and did not use armor did not simply leave the pilots at risk. Such an approach also placed additional restrictions on the aircraft. The Zero was nimble but at speeds over 220 Kts it was almost a sitting duck, neither able to roll into a turn quickly nor flip into a climb or a dive.
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Which one of those lightweight fighters was in frontline service and where did they serve?, having no pilot armor or protection especially SS tanks didn't leave the pilot at risk?.

 

[SaparotRob]

Don't think the F8F was ever intended for escort.

I hope you didn't think I said the Bearcat was used for escort. I meant quite the opposite.

 

[tyrodtom]

I've read about Saburo Sakias account of a prolonged combat between him and several Hellcats late in the war when he returned to combat status after recovering partially from his injuries.

I don't remember the number of Hellcats, maybe 6, that he couldn't outrun, but he constantly avoids by banking and rolling out of the way, while the Hellcats pilots were low on experience, and constantly got in each others way, which certainly helped.
But Sakia said nothing about flying along at his best maneuvering speed while trying to get away, that would seem counter-intuitive. But he was extremely exhausted after he finally did get away.
A test pilot flying a aircraft is in a calm, controlled environment , a pilot in combat has the advantage of adrenalin, you can do things when you're scared, or excited, that you'd never think you could do.

 

[Thumpalumpacus]

The Zero was nimble but at speeds over 220 Kts it was almost a sitting duck, neither able to roll into a turn quickly nor flip into a climb or a dive.

What's your source for this if you don't mind?

 

[buffnut453]

Which one of those lightweight fighters was in frontline service and where did they serve?, having no pilot armor or protection especially SS tanks didn't leave the pilot at risk?.

I think that his point is that lack of armour DID put pilots at risk but had other consequences on agility at high speeds.

I had to read the post a few times to grok the point being made.

 

[PAT303]

What's your source for this if you don't mind?

The RAAF test mentioned the controls were incredibly hard to move at high speed, when flying a Spitfire or P40 the rule was keep your speed up because the A6M then couldn't turn with you.

 

[yulzari]

One should bear in mind that altering the A6M ailerons to remain effective at higher speeds will impact the weight of the wings etc. to bear the additional forces twisting the wings. You cannot get a free lunch so have to cope with just a cheap lunch. In the case of the A6M you get an excellent main course but no pud to follow. The later versions managed to add an amuse bouche or perhaps a small starter but still no pudding.

 

[MiTasol]

Well, the US did build lightweight fighters that had little or no armor. We just did not produce them in large numbers. And that P-66 sure looks like a Zero.

However, as the article from Corky shows, building an airplane that was lightweight and did not use armor did not simply leave the pilots at risk. Such an approach also placed additional restrictions on the aircraft. The Zero was nimble but at speeds over 220 Kts it was almost a sitting duck, neither able to roll into a turn quickly nor flip into a climb or a dive.
View attachment 795357View attachment 795358View attachment 795359View attachment 795360

The early P-36 and P-40 aircraft were totally lacking in both armour and self sealing tanks so they were no better than the A6M at that time. They were first fitted to P-36 and P-40 aircraft ordered for Britain and France. I suspect the first P-38s and 39s may have also lacked those items although the British and French demands and experience were starting to penetrate the US design philosophies by the time Pearl Harbor happened.

The British Tomahawks had fairly light seat armour which was heavier on the D/E aircraft and heavier again as the models progressed. Likewise their frontal protection grew with each model except that they removed the coolant tank armour on the D and subsequent aircraft.

As for the P-66 looking like an A6M all I can say is that you must think the Hurricane looks like the Mustang.