A6M Zero Wings Would Snap Off in A 6G Turn?

[P-39 Expert]

Interesting, the IJN pilots were ripping the radios out of their Zeros because the radio was rubbish.

Explains a lot about Midway. No voice communication between the carriers and their CAP or within the CAP. Couldn't shield their radios from ignition interference. Bad on them.

Hadn't heard about the atmospheric conditions having such a profound effect. Edwards Park in "Angels Twenty" and "Nanette" complained bitterly about AAF radios stating the Japanese radios were much better. Of course he didn't know that most of the Zero radios had been removed. And he didn't know they were in the radio "Black Hole" of the entire world. :}

I wonder if the radar was affected by those same atmospheric conditions? Park said that most radar intercepts were against clouds or a flock of birds.

 

[contrails16]

Hi Contrails 16.

I have seen films of it, but never the actual aircraft. That particular aircraft had a very slightly bent propeller blade and could not fly at full power due to vibration, but there was no chance of getting a new propeller.

At the time, there was absolutely no interest in a flying Japanese fighter at U.S. airshows, so it was eventually sold to a Japanese museum. It was transferred to the Arashiyama Museum in Kyoto in 1973 for display. With unsupervised access allowed to the aircraft, parts were stolen from the Ki-84, and coupled with the years of neglect it could no longer fly. Following the museum's closure in 1991, the aircraft was transferred to the Tokko Heiwa Kinen-kan Museum, Kagoshima Prefecture, where it still is displayed to this day. When they came to get it, they cut the wings off with a chain saw (!) and re-assembled it with non-flyable repairs. It is the only surviving Ki-84.

that is awful!!!!! I didn't know about the chainsaw part! I knew everything else, but wow that they chainsawed the wings off! Who chainsawed the wings, the Americans or Japanese?

 

[GregP]

The Japanese who purchased it. They likely knew it was going to be static and wanted to ensure it never flew again.

In fact, it COULD fly again ... but it would take a new wing spar in addition to the restoration needed. The museum is in a downtown area, so it is nowhere NEAR an airport.

 

[MikeMeech]

I wonder if the radar was affected by those same atmospheric conditions? Park said that most radar intercepts were against clouds or a flock of birds.

Hi

Certainly it did happen, for example during some of the final attacks against the Japanese mainland:

"... the combined US/British Task Force encountered exceptionally severe anomalous propagation, so that the SM-1 beams were trapped just above the sea surface, providing wonderful low cover but no heightfinding; and the USN had neglected height estimation for which the SK was in any case not suitable because of the many lobes at 1.5m wavelength. Type 281 and the elderly type 79 came into their own." (p.251, 'Radar at Sea - The Royal Navy in World War 2' by Derek Howse)

The atmospheric conditions could cause problems depending on the wavelength of different radar equipment, so probably a good idea not to have all ships equipped with the same type during WW2 if possible.

Mike

 

[contrails16]

The Japanese who purchased it. They likely knew it was going to be static and wanted to ensure it never flew again.

In fact, it COULD fly again ... but it would take a new wing spar in addition to the restoration needed. The museum is in a downtown area, so it is nowhere NEAR an airport.

Wow, that pacifism kinda is a double-edged sword I guess. It sucks that they did that. Have they done this to other historic warplanes that you know of ?

 

[GregP]

Not that I know of. That doesn't mean it hasn't happened.

A friend of mine back in the 1990s in Arizona purchased a MiG-15 UTI from the Chinese People Air Museum outside of Beijing, They cut out about a 1-foot section of wiring harness about every 4 feet. For the aircraft to operate, it had to be completely rewired. They also reversed every other check valve in the hydraulic system and it took a couple of weeks of head scratching to get that worked out. When we connected a hydraulic pressure source to it and first tried to operate it, all the controls were frozen in place. Some basic troubleshooting made that easier after we found the first one that was reversed. After that, it was easy.

After the experience, I would never purchase anything of significance from China. They actively sabotaged the aircraft, but did not cut the wing spars. Conversely, they left the cannons armed and we had to call ATF to get them to come over and make everything legal. ATF was not happy and was about as friendly as China was. They cut the guns up into 7 pieces! We had to weld them back together and put them back in place for weight and balance purposes. Without the cannons, the aircraft wanted to rock back onto the tail. I suppose they thought we wanted to fly the aircraft armed! If that were actually the case, why would we have called them in the first place? Seems like a good way to go to jail!

When I say, "we," I mean my friend. I was an interested observer only. Deere Valley Airport was and likely remains a hotbed of warbirds. I helped get the MiG airworthy, but never owned any part of it. I DID get to taxi it once. Interesting as it had no steering. You steer it with the brakes and the nosewheel casters freely. I think many early jets operate that way and some tricycle gear pistons, too. The P-38 and F7F have castering nosewheels and steer with brakes and/or power changes.

If you go to Deere Valley Airport, you can see CJ-6s, PZL TS-11s, MiGs (15 / 17), some AT-6s, used to be a couple of operating F-104s, a couple of A-3s, and 1 or 2 T-33 / CT-133s, coupled with other exotics, mostly aerobats. I've seen Yak-50s and 52s there along with the odd Su-29 / 29 / 31 and some interesting, rare planes like a CW-22 or 23, can't recall which now.

 

[contrails16]

Not that I know of. That doesn't mean it hasn't happened.

A friend of mine back in the 1990s in Arizona purchased a MiG-15 UTI from the Chinese People Air Museum outside of Beijing, They cut out about a 1-foot section of wiring harness about every 4 feet. For the aircraft to operate, it had to be completely rewired. They also reversed every other check valve in the hydraulic system and it took a couple of weeks of head scratching to get that worked out. When we connected a hydraulic pressure source to it and tried to operate it. All the controls were frozen in place. Some basic troubleshooting made that easier after we found the first one that was reversed. After that, it was easy.

After the experience, I would never purchase anything of significance from China. They actively sabotaged the aircraft, but did not cut the wing spars. Conversely, they left the cannons armed and we had to call ATF to get them to come over and make everything legal. ATF was not happy and was about as friendly as China was. They cut the guns up into 7 pieces! We had to weld them back together and put them back in place for weight and balance purposes. Without the cannons, the aircraft wanted to rock back onto the tail. I suppose they thought we wanted to fly the aircraft armed! If that were actually the case, why would we have called them in the first place? Seems like a good way to go to jail!

When I say, "we," I mean my friend. I was an interested observer only. Deere Valley Airport was and likely remains a hotbed of warbirds. I helped get the MiG airworthy, but never owned any part of it. I DID get to taxi it once. Interesting as it had no steering. You steer it with the brakes and the nosewheel casters freely. I think many early jets operate that way and some tricycle gear pistons, too. The P-38 and F7F have castering nosewheels and steer with brakes and/or power changes.

If you go to Deere Valley Airport, you can see CJ-6s, PZL TS-11s, MiGs (15 / 17), some AT-6s, used to be a couple of operating F-104s, a couple of A-3s, and 1 or 2 T-33 / CT-133s, coupled with other exotics, mostly aerobats. I've seen Yak-50s and 52s there along with the odd Su-29 / 29 / 31 and some interesting, rare planes like a CW-22 or 23, can't recall which now.

That's awesome

 

[davparlr]

I believe it was a combination.
Poor shielding on the engine ignition system and not the best radio.

I would note however that a number of aircraft had radio problems and the First P-47s to go into service in Europe did so with British radios (the American ones were pulled out and British ones installed) after a several weeks of trying to get the US radios to work properly.

Both books I've read on early Navy combat, "The First Team" and "The First Team and the Quadalcanal Campaign", indicated that US Navy communications was a problem, often significantly, especially when enemy force reports do not make it back to Command.

 

[davparlr]

When I say, "we," I mean my friend. I was an interested observer only. Deere Valley Airport was and likely remains a hotbed of warbirds. I helped get the MiG airworthy, but never owned any part of it. I DID get to taxi it once. Interesting as it had no steering. You steer it with the brakes and the nosewheel casters freely. I think many early jets operate that way and some tricycle gear pistons, too. The P-38 and F7F have castering nosewheels and steer with brakes and/or power changes.

I believe the P-80/T-33 needed to be steered with the brakes and had a castering nose wheel, which, according to one of my friends, could get cocked.

 

[Conslaw]

This video, from Greg's Aircraft and Automobiles, goes into a lot of the theory of aircraft maneuverability. I didn't watch it like I was studying for a test, but what I took from it was that an aircraft's sustained turn rate is largely determined by its excess power., and on this basis the P-47 rates well for turning ability at high altitude because it keeps its power to higher altitude than most fighters. Similarly, at low altitude it was not great. I don't know whether the Zero had enough excess power to get anywhere near the 6g range on a sustained basis. As far as momentary G forces, like pulling out of a dive, I don't know how they weigh or rate momentary versus sustained "G" forces.

 

[FLYBOYJ]

I DID get to taxi it once. Interesting as it had no steering. You steer it with the brakes and the nosewheel casters freely. I think many early jets operate that way and some tricycle gear pistons, too. The P-38 and F7F have castering nosewheels and steer with brakes and/or power changes.

This is common to the majority of east block combat aircraft and to add to this the brake is a bicycle grip on the stick. This is from a flight manual, you can see the brake handle protruding off the control stick.

 

[FLYBOYJ]

Some comments here...

I don't see the wing of a Zero just "snapping" off. The aircraft had a continual spar but it was spliced together in 2 places, but despite this the wings weren't separate left/ right units. The wing separated from the fuselage as one complete assembly.

Here is a great design analysis of the A6M3 "Hamp," it might have been posted on this forum previously.

Design Analysis of the Zeke 32 (Hamp - Mitsubishi A6M3)

IMO if you were able to get a Zero into an over G condition, I think you would first have certain segments of the aircraft bend to the point where it would perpetuate failure points at the aileron and elevator hinge points, probably the weakest part of the continual structure. Once those areas fail, the whole thing could potentially ball up. There are other factors to consider, as already mentioned, battle damage, but even field repairs could factor in as well as aircraft weight.

 

[wuzak]

This video, from Greg's Aircraft and Automobiles, goes into a lot of the theory of aircraft maneuverability. I didn't watch it like I was studying for a test, but what I took from it was that an aircraft's sustained turn rate is largely determined by its excess power., and on this basis the P-47 rates well for turning ability at high altitude because it keeps its power to higher altitude than most fighters. Similarly, at low altitude it was not great. I don't know whether the Zero had enough excess power to get anywhere near the 6g range on a sustained basis. As far as momentary G forces, like pulling out of a dive, I don't know how they weigh or rate momentary versus sustained "G" forces.

I was going to ask if any WW2 piston fighter could perform a 6G turn. Maybe momentarily, but not sustained?

 

[GregP]

There is some g load factor and turn rate that can be sustained in a level turn at a constant bank angle with the power available at any altitude.

Anything more than that g-level, and you will need to either lose height to sustain the energy required or lose speed and eventually HAVE to lighten the load or stall when you get down near stall speed.

But, a P-51 going, say, 310 mph, could easily snap over into a 6-g turn and stay there until he needs to back off, stall out, or lower the nose. The instantaneous-g I keep hearing about, is that g load above the sustained turn load factor. It starts out high, and slowly loses g-load until it is at the sustained turn rate or the pilot lines up and doesn't need to turn anymore, and so unloads the wing. The higher the g-load, the faster the aircraft loses speed in the turn. When the aircraft reaches so-called "cornering velocity," it is AT speed where the sustained turn is possible.

Someone like BiffF15, FlyboyJ, or DerAdler can very probably word that better.

 

[ThomasP]

Hey wuzak,

If by sustained you mean could it maintain a 6g turn while maintaining altitude indefinitely, the answer is no. The best turning of the higher performing propeller driven aircraft in WWII could (in theory) sustain a level turn at just under 3g at SL.

Most of the WWII aircraft could enter a 6g turn, but none could sustain it for more than a few seconds unless they traded altitude for energy. Even then they would not be able to sustain 6g for very long.

 

[Conslaw]

The US Navy began experimenting with anti-g suits as early as November 1942. In March 1944 came the first combat trials, according to this article. Multiple suits were available to participants of the Joint Fighter Conference in August 1944 for use in aircraft that could accommodate them. What aircraft that would be, I don't know. Definitely the F6F.

 

[drgondog]

This video, from Greg's Aircraft and Automobiles, goes into a lot of the theory of aircraft maneuverability. I didn't watch it like I was studying for a test, but what I took from it was that an aircraft's sustained turn rate is largely determined by its excess power., and on this basis the P-47 rates well for turning ability at high altitude because it keeps its power to higher altitude than most fighters. Similarly, at low altitude it was not great. I don't know whether the Zero had enough excess power to get anywhere near the 6g range on a sustained basis. As far as momentary G forces, like pulling out of a dive, I don't know how they weigh or rate momentary versus sustained "G" forces.

The turn rate is a factor of High AoA CLmax, Excess Power, Velocity, Wing loading, Max G sustainable and of course Drag (parasite, pressure and induced). The reason that everybody wishes to simplify the equations and variables, particularly for reciprocal engines, is that 'it is complicated in real world'.

The important factors of Excess Power include the drag losses (pressure recovery, induced and parasite drag) from Power Available. Pressure drag recovery include carb duct, radiator/ducting cooling drag, and incremental pressure drag within the prop vortex stream over the inboard 1/3 span and fuselage. It is all about deriving Thrust and Drag ------> Thrust >drag = possible acceleration in the turn to the limit of both stall CLmax and G limit at constant altitude or ability to climb with same turn rate and V.,

Propeller efficiency to deliver Thp is squirrely at high power low/speed for different aircraft, turn is asymmetrical compared to loop and differential wing pressure distribution due to different angles of attack of each aileron (or slat) require trim drag increments due to rudder inputs to carve an optimal turn so classic methods of calculating top speed in level flight don't quite apply to turning flight.

The basic equations of Performance taught in USAF/USN aero courses and undergrad school with get you in the ballpark, but you should not get giddy when making comparisons unless to have boatloads of data on the airframe, prop and engine as a function of altitude.

 

[gomwolf]

AFAIK, Zeke's ultimate loadfactor is 7.5 and safty factor is 1.8. Actually, it is their ROC when they start making this plane. So it's endurance in maneuvering is quite good. But Japanese, at that time, has no engineering technology and infomations about structual problems at high speed flight. Most of their mid-air disintegration was occured by flutter at high speed.

So it is not about G, but speed.

 

[GregP]

Zeke / Zero load factor is 6 with safety factor of 2, so 12 g ultimate, but stressed to 6 g for normal operations.

 

[wlewisiii]

Wow, that pacifism kinda is a double-edged sword I guess. It sucks that they did that. Have they done this to other historic warplanes that you know of ?

I'd bet it was more the thinking that "this is the last one. If it flies, it is at terrible risk. If we do this, no one will be tempted to fly and risk crashing it".