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

[XBe02Drvr]

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 problem with any heavy G load, momentary or sustained, is that the air is seldom glassy smooth. Any "bump" in the air, whether due to thermal action, mountain wave, or shears or vorticity, or even somebody else's wake turbulence, while near the flight load limit will flex the structure into its plastic range, where it won't immediately fail, but will accumulate stress cracks which weaken its reserve strength. Repeated excursions will increase its range of flexibility and lower the plastic threshold at which damage accumulates. Eventually you have a "clapped out" aircraft that has a dramatically lowered ultimate G load.
Now put said aircraft in a high G maneuver and start punching .50 cal or 20 MM holes in critical structural members, and you're likely to see some pretty drastic consequences. Contrary to popular conception, the first things to fail are apt to be the horizontal stabilizer or the engine mount structure, either of which will generate a pitch up or down that instantly overstresses the wings.
I'm not an engineer, so I may have misused some of the terminology here. Any of you who are, feel free to correct me on this. (In "everyday language" if you can.)
Cheers,
Wes

 

[Big Jake]

It's all academic - in WW2, before the g-suit, pilots would pass out way before the aircraft reaches its design max load. I recall asking a pilot, during a test flight after a major repair, to pull 4g on a T-6. When he came back I asked how it was and whether he pulled the g's and his reply was that he tried but felt he's passing out and never reached 4. By the way, I wasn't worried about the 4g - in 1944, for some reason, the USAAF took a T-6 and tested its structure to find out how strong it is. At 8g the first damage occurred - a twisted outer wing. They stopped the test, happy with the results.

 

[XBe02Drvr]

before the g-suit, pilots would pass out way before the aircraft reaches its design max load.

When I had my nighttime inadvertent IMC upset in the T34, I came out of cloud base at about 1200 MSL in a fully developed graveyard spiral at around 200 Kts. In the subsequent panicked bank and yank, I don't believe I ever lost consciousness, as I distinctly remember seeing a faint glow in the water below me and realizing it was my nav lights reflecting, but the G meter recorded 7Gs. I almost pulled a JFK Jr, but the wings stayed on my plane.
BTW, the rotating beacon on a T34, which sits on the fuselage immediately aft of the canopy, is a real vertigo generator when you suddenly find yourself inside a cloud at night with no IFR ticket under your belt.

 

[contrails16]

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".

Aero Detail #24 says that it's rumored the wings were severed in order to make storage easier while it was being transferred between museums sadly.

 

[Peter Gunn]

When I had my nighttime inadvertent IMC upset in the T34, I came out of cloud base at about 1200 MSL in a fully developed graveyard spiral at around 200 Kts. In the subsequent panicked bank and yank, I don't believe I ever lost consciousness, as I distinctly remember seeing a faint glow in the water below me and realizing it was my nav lights reflecting, but the G meter recorded 7Gs. I almost pulled a JFK Jr, but the wings stayed on my plane.
BTW, the rotating beacon on a T34, which sits on the fuselage immediately aft of the canopy, is a real vertigo generator when you suddenly find yourself inside a cloud at night with no IFR ticket under your belt.

Wes, I'm on the fence here, after reading many of your posts (with great interest BTW) I'm not sure if I'd want to even walk near an aircraft with you back in the day or not, let alone fly in it with you. I mean, the above story is certainly a candidate for new unmentionables as they say, but on the other hand, it takes a great pilot to get out of that situation.

I kid, I'd have flown with you any day.

 

[BiffF15]

It's all academic - in WW2, before the g-suit, pilots would pass out way before the aircraft reaches its design max load. I recall asking a pilot, during a test flight after a major repair, to pull 4g on a T-6. When he came back I asked how it was and whether he pulled the g's and his reply was that he tried but felt he's passing out and never reached 4. By the way, I wasn't worried about the 4g - in 1944, for some reason, the USAAF took a T-6 and tested its structure to find out how strong it is. At 8g the first damage occurred - a twisted outer wing. They stopped the test, happy with the results.

Big Jake,

There is a large variation in what contributes to a persons relaxed G tolerance. The big variables that drive it are the hardness of the arteries, the distance from the heart to the head, and how much they have recently been doing high g flying. Four is on the low side in my experience. A short stocky smoker will have a much higher limit than a tall lanky runner (runners have unique problems based on the flexibility of their arteries which stretch and allow pooling of blood. Not good as the hydraulic pressure drops which the opposite of what's needed.).

In combat, with adrenaline coursing in large amounts through ones body, as Wes spoke to above, your tolerance would rise tremendously. The Blue Angels fly a 7.3 G jet in their routine (F-18). They do it without a G suit (not smart but that's another conversation).

Cheers,
Biff

 

[Icorps1970]

Did any piston-powered, single-engine, single-seat, monoplane fighter tear off its wings under loads that the pilot could physically sustain?

It was not necessary to sustain the load, just achieve it, no pilot in WW-II is going sustain 6-8 gs for any length of time. While the official version was "turbulence" Robert S. Johnson stated that Zemke "pulled the wings off his P51". I suspect that he got this direct from Zemke after the war but have no way of knowing this was the case. Its thought that McGuire pulled a wing(s) off his P38 since he had flown back with wrinkled wings a couple of times previous. We have no idea if this happened to others since losing a wing would make bailout difficult.

 

[DerAdlerIstGelandet]

Wes, I'm on the fence here, after reading many of your posts (with great interest BTW) I'm not sure if I'd want to even walk near an aircraft with you back in the day or not, let alone fly in it with you. I mean, the above story is certainly a candidate for new unmentionables as they say, but on the other hand, it takes a great pilot to get out of that situation.

I kid, I'd have flown with you any day.

 

[XBe02Drvr]

I'm not sure if I'd want to even walk near an aircraft with you back in the day or not, let alone fly in it with you.

I've been fortunate in my flying days to have the opportunity to seek out (and fall into) a variety of aviating experiences, influenced by Chuck Yeager's quote: "The pilot with the greatest experience will be the survivor". This is true of many, if not most fliers, but most aren't willing to discuss their dumbshits and their screwups in public. I think there's a lesson to be learned, and perhaps a little amusement to be had from each of these indiscretions from the days of young and foolish. Guess I'm the eternal instructor at heart.
Lesson learned. I never again flew on a hazy, puffyCU, sliver-moon night until I had my instrument ticket. Those bright red reflections racing around the plane just beyond the wingtips tumbled my internal gyro instantly, and the worn, uncalibrated, rapidly precessing gyros in the plane didn't help either. I knew what a graveyard spiral was, and realized I was in one, but couldn't fly out of it because the instruments just weren't making sense. I succeeded a couple times but couldn't maintain stable flight because I was so disoriented. I'd get briefly stabilized, wait for the mag compass to settle down (gyro compass totally tumbled and going in lazy circles), then try to turn back on course and lose it again. Eventually it dawned on me to turn the rotating beacon off, but that was only just before dropping out of the clouds and seeing the hard and shiny water staring me in the face. Boat and island lights gave me an instantaneous attitude reference, and I wasn't looking at the altimeter when I leveled out but I was LOW!
I don't know if the 7Gs was from the pullout, some gyration in the cloud, or my rather shaky landing back at Boca Chica. And I don't care!
Cheers,
Wes

 

[XBe02Drvr]

View attachment 590314

Ice is da man! Maverick's a loose cannon.

 

[pinsog]

When I had my nighttime inadvertent IMC upset in the T34, I came out of cloud base at about 1200 MSL in a fully developed graveyard spiral at around 200 Kts. In the subsequent panicked bank and yank, I don't believe I ever lost consciousness, as I distinctly remember seeing a faint glow in the water below me and realizing it was my nav lights reflecting, but the G meter recorded 7Gs. I almost pulled a JFK Jr, but the wings stayed on my plane.
BTW, the rotating beacon on a T34, which sits on the fuselage immediately aft of the canopy, is a real vertigo generator when you suddenly find yourself inside a cloud at night with no IFR ticket under your belt.

I'm sitting on my back porch next to the pool sipping on a Coke and I still crapped my pants just reading your story.

 

[wuzak]

Big Jake,

There is a large variation in what contributes to a persons relaxed G tolerance. The big variables that drive it are the hardness of the arteries, the distance from the heart to the head, and how much they have recently been doing high g flying. Four is on the low side in my experience. A short stocky smoker will have a much higher limit than a tall lanky runner (runners have unique problems based on the flexibility of their arteries which stretch and allow pooling of blood. Not good as the hydraulic pressure drops which the opposite of what's needed.).

In combat, with adrenaline coursing in large amounts through ones body, as Wes spoke to above, your tolerance would rise tremendously. The Blue Angels fly a 7.3 G jet in their routine (F-18). They do it without a G suit (not smart but that's another conversation).

Cheers,
Biff

Does seating posture also play a part?

IIRC the British found testing the Bf 109 and Fw 190 that the seating position was slightly more reclined, with the legs outstretched, than in the Spitfire and Hurricane, which gave a slightly better tolerance to G-forces.

 

[BiffF15]

Does seating posture also play a part?

IIRC the British found testing the Bf 109 and Fw 190 that the seating position was slightly more reclined, with the legs outstretched, than in the Spitfire and Hurricane, which gave a slightly better tolerance to G-forces.

Wuzak,

Yes, seating position can play a big part. The F16 has a reclined seat and the pilots knees are above the waistline IIRC. Positive G force pushes the blood lower in the body when it needs to stay higher (heart, brain, eyes). The Eagle sits very upright which is tougher G wise but much easier on the neck.

Between WW2 and now we figured out the L-1 straining maneuver to help keep the blood from draining and pooling in the lower extremities. Added a G suit at the end of WW2 that went almost unchanged until about five years ago. New G suit is like a pair of pants and works extremely well. Extremely expensive as well, think it runs about 5k per pair...

Cheers,
Biff

 

[pinsog]

Wuzak,

Yes, seating position can play a big part. The F16 has a reclined seat and the pilots knees are above the waistline IIRC. Positive G force pushes the blood lower in the body when it needs to stay higher (heart, brain, eyes). The Eagle sits very upright which is tougher G wise but much easier on the neck.

Between WW2 and now we figured out the L-1 straining maneuver to help keep the blood from draining and pooling in the lower extremities. Added a G suit at the end of WW2 that went almost unchanged until about five years ago. New G suit is like a pair of pants and works extremely well. Extremely expensive as well, think it runs about 5k per pair...

Cheers,
Biff

$5,000 per pair??!! So if you have an incident like XBe02Drvr told above you have to have them cleaned instead of just throwing them away?

 

[XBe02Drvr]

$5,000 per pair??!! So if you have an incident like XBe02Drvr told above you have to have them cleaned instead of just throwing them away?

There's still your flight suit (AKA, "poopie suit") between your high priced "sweat pants" and the scene of the action. Even back in my day (early 70s) G suits were cleaned, not thrown away. A couple of PR (Aircrew Survival Equipmentmen, "parachute riggers" in the vernacular) drinking buddies lived just down the hall in the barracks.

HISTORICAL NOTE: PRs started out between the world wars as simple parachute riggers, but as aircraft performance advanced, so their responsibilities expanded to include helmets, oxygen gear, life rafts, survival kits, aircrew personal sidearms, etc through WWII. Then along came jets, and G suits, ejection seats, cockpit safety systems, emergency communications radios, and the like joined the mix. Downright busy folks, and the finest seamsters in town if you need to get your sails patched or a set of reefpoints put in.

 

[pinsog]

There's still your flight suit (AKA, "poopie suit") between your high priced "sweat pants" and the scene of the action. Even back in my day (early 70s) G suits were cleaned, not thrown away. A couple of PR (Aircrew Survival Equipmentmen, "parachute riggers" in the vernacular) drinking buddies lived just down the hall in the barracks.

HISTORICAL NOTE: PRs started out between the world wars as simple parachute riggers, but as aircraft performance advanced, so their responsibilities expanded to include helmets, oxygen gear, life rafts, survival kits, aircrew personal sidearms, etc through WWII. Then along came jets, and G suits, ejection seats, cockpit safety systems, emergency communications radios, and the like joined the mix. Downright busy folks, and the finest seamsters in town if you need to get your sails patched or a set of reefpoints put in.

That is a fantastic technical explanation, which I have come to expect from you and several others here, BUT I can assure you if I had been in that aircraft with you, assuming I survived the ensuing heart attack and stroke I would have had as we spun out of the sky, they would have taken a single look at my suit and either buried me in it or thrown it away!!!!!

"Scene of the action" love that! I'm laughing like an idiot while my wife is staring at me!

(Keep the personal stories coming guys, they are as good as any information that comes out of the debates and I personally love reading them)

 

[XBe02Drvr]

I can assure you if I had been in that aircraft with you, assuming I survived the ensuing heart attack and stroke I would have had as we spun out of the sky, they would have taken a single look at my suit and either buried me in it or thrown it away!

I wouldn't have wanted to be along for that ride either. When you're a hostage and not driving the bus, you have time to indulge in heart attacks and strokes, but when you've got the stick in your sweaty hand, you're too damn busy for such luxuries.
I've got to hand it to the T34, she's a rugged, intuitive flyer. If I'd been flying JFK Jr's Saratoga, I wouldn't be here today. And I was a low-timer, barely 160 hours, the previous 60 in the T34. In today's world nobody would let me near a Saratoga (or a T34) with so little time.

 

[nuuumannn]

Did any piston-powered, single-engine, single-seat, monoplane fighter tear off its wings under loads that the pilot could physically sustain?

Not so much wings, but the Bf 109F lost its tailplane during trials and pilots were killed as a result, let's not forget the Hawker Typhoon's tendency for its tail section to snap off under load.

This is true of many, if not most fliers, but most aren't willing to discuss their dumbshits and their screwups in public.

Engineers too!

 

[davparlr]

It is weird that you brought this up as I watched a pretty good video last night that delves deeply into the structural strength of the the A6M and other aspects of the fighter as well.

One complaint I have about the video was that the author went out of his way to list reasons the Zero was so successful against the Spitfire including inexperienced pilots, he failed to mention that there is a good possibility that the Zero was so successful against the P-39 was also the inexperience of the AAF pilots this early in the war.

 

[P-39 Expert]

One complaint I have about the video was that the author went out of his way to list reasons the Zero was so successful against the Spitfire including inexperienced pilots, he failed to mention that there is a good possibility that the Zero was so successful against the P-39 was also the inexperience of the AAF pilots this early in the war.

Yep.