The Zero's Maneuverability

[nuuumannn]

The Zero had quite a complex hydraulic system operating the flaps, landing gear retraction and brakes, so much so that the US commentator wrote during a test report on the A6M5 that its hydraulic system was unnecessarily complex. The Zero's gear was robust enough for the punishing regimen of operating from carriers and the rough island strips the type found itself relegated to once the IJN lost its carriers. Oddly however, the Zero didn't have a park brake, which raised criticism in Allied test reports, meaning that on the ground, the pilot had to stamp on the brakes throughout ground runs.

NX712Z 01

 

[RCAFson]

Here's an article from Naval Aviation News, the 1 Oct 1945 issue, which while explicitly referring to the FM series, is applicable to the F4F as well, pages 24-25

Wildcat Factograph

An appalling proportion of the FM's rolling off the production line were wrecked or damaged before a year was out due to accidents with the pilot at the controls, and, without a Jap in sight. The cost of Wildcats thus wrecked, plus the cost of replacing damaged parts of repairable aircraft, has run into many millions of dollars a year, representing the annual labor of thousands of men. In about seven out of 10 cases, boards assigned pilots primary responsibility, and in others they were held partially responsible. An analysis of 1000 pilot caused Wildcat mishaps covering somewhat less than a year, placed three-fourths of them in seven specific categories: groundloops and swerves (27%), hard or bounce carrier landings (14%), failure to lower or lock wheels down (12%), pilot-caused engine failure (7%), hold-off barrier crashes (5%), spins on landing approach (5%), and nose-ups while taxiing (5%). An analysis of all the crashes studied follows.

Groundloops And Swerves -

The difficulty in maintaining directional control on the ground is a most prolific source of trouble in the narrow-geared FM, accounting for one out of every four pilot caused accidents. Every landing in the FM is a potential groundloop; you can't just sit there and let it land itself. Before beginning your approach, be sure your tail wheel is locked, and brakes pumped. To avoid landing in a skid, contact the tower for information on crosswinds and gusts, and be sure the designated runway is the one most nearly into the wind. If your approach is ragged, or if there is danger of slipstreams, you can avoid trouble by taking a wave-off.

After you have landed keep your eyes peeled for embryonic groundloops. Line up with a reference point, avoid depending on the rudder after you have slowed down to 35 knots, beware of over-correcting, and leave that tail wheel locked until you can turn safely.

In carrier landings you can avoid the catwalk by a good approach. If you angle in, land off center, or land with one wing down, you can't expect to stay on the deck.
During takeoffs, in addition to insuring that the brakes are right, and the tail wheel locked, there is that little matter of rudder tab – 2½ marks nose-right in the normal case, but less or more, depending on the direction and the strength of the crosswinds. If it's touch-and-go, apply the throttle for the take-off, promptly, to help maintain control, but smoothly, to avoid torque. When you are taking off from a carrier, make certain that you release both brakes at the same instant, and that you don't get excited and over correct if your FM starts veering toward the catwalk.

Groundloops and swerves while taxiing simply shouldn't happen, but every few days some pilot promotes an accident by attempting a turn with excess speed, by catching his plain's tail in a slipstream, by failing to check his brakes, or by fast taxiing. Many accidents occurring during the take-off or landing, really begin with the pilot asking for trouble by riding his brakes on a taxi strip coincident with excessive throttle, or in a stiff cross-wind.

You can't avoid groundloops in the FM by experience alone. There is no substitute for constant vigilance.

Spins During Landing Approach –

Approximately five out of every seven spin-stall accidents in the FM occur during the landing approach, especially during field-carrier landing practice. The turn to final approach is the point of incidence of the largest portion of these accidents, but the turn to the cross-wind leg and the groove itself also claim a substantial share. Spins during wave-offs are not uncommon, especially following slow, mushing carrier or field-carrier approaches.

Frequently, the stall originates upon hitting an unexpected slip stream; sometimes after slowing down excessively to lengthen the interval between the planes. In other cases, the pilot overshoots the groove, or makes his crosswind leg too close aboard, and finds himself in a tight turn into final with inadequate lift.

The penalties of a slow approach (in the form of spins, colliding with obstructions, undershooting, etc.) are frequent and serious. Hence, insofar as airspeed during the approach is concerned, by all means don't err on the slow side. Rather than attempt a steep bank into the groove to correct over shooting, take a wave-off. But in taking the wave-off, be sure to level your wings as you ease on the throttle and be on the alert for the tendency of the nose to rise.

Pilot-Caused Engine Failure –

The FM single tank fuel system is simplicity in the extreme, but that doesn't stop some pilots from having fuel troubles. One favorite trick is to turn the selector valve to a non-existent "droppable" or "off," while intending to actuate the adjacent flap control. Another is to fly dumbly along with a stuck fuel gauge, apparently the gas to last forever. To keep yourself out of fuel troubles, make sure your tank is topped-off properly before you begin your hop, adjust your mixture, your RPM, and your manifold pressure, so you will end up with the most gas in your flight – not the least; and return to base promptly and at economical speed if your gas gets low, calling the tower for an emergency landing if you have the slightest doubt about the quantity of fuels remaining.

A considerable portion of pilot-caused engine trouble in the Wildcat takes place during the take-off. Throttle-creep sometimes occurs when the pilot removes his hand from the throttle to crank up the wheels, so don't neglect the friction-brake knob. Attempted take-off with the engine loaded up after long idling is another frequent error, the cure being a. always make the 5-second idle mixture check which is discussed in TO 80-44, and b. always clear engine fully after long idling.

During touch-and-go practice (and wave-offs), pilots occasionally get into engine difficulties by failing to adjust prop pitch and mixture controls; also, the sudden jamming on of throttle sometimes causes the FM engine to falter or fail completely in a crisis.

Hold-Off Barrier Crashes –

Hold-off barrier crashes are the fifth most frequent type of pilot cause Wildcat accident. In the typical case, the pilot makes a somewhat fast approach, takes the cut, but fails to fly the airplane down to the deck. Or the pilot may make contact with the deck but fail to force and hold the tail down with the stick. Occasionally an accident has its inception in failure to chop the throttle completely and immediately upon receipt of the LSO's signal.

When the cut is taken, don't "horse" back on the stick immediately. This will float you into the barrier or stall you out high. The stick should not be pulled back until the plane has started to settle. Then it should be eased back to cushion the landing.

Admittedly, it takes some pretty fancy piloting, coupled with keen depth perception, to fly down to the deck without diving, and to get and hold the tail down without floating. But the task is made easier with a good approach, which means immediate response to all of the LSO's signals.

Hard or Bounce Landings –

The shock of hard landings is not readily absorbed by the short oleo struts of the FM landing gear, nor does the short deck of a jeep carrier, from which the FM operates, permit much of a bounce before you find your prop chewing up the barrier. So, in the Wildcat, you have to avoid diving for the deck as you would avoid the plague.
Stay out of trouble by replying promptly to the LSO's signals relative to altitude and speed. When you get the cut, do not drop your nose, for if you do, you are sure to hit hard and bounce into the barrier; or if you luckily have caught a wire, damage your aircraft in the landing area. Hold your nose in the position it is in at the time of the cut. When you commence to settle in this attitude, ease the stick back.

Wheels Up Or Unlocked –

The FM, only Navy combat plane with a hand-cranked landing gear operating mechanism, has its own unique causes of numerous wheels-up landings. The hand crank normally requires 28 turns to get the wheels down. It's a good idea to count your turns, but don't depend upon count alone, for in some cases more turns are required. A point is reached in turning the crank handle at which it becomes difficult to rotate the handle. But don't stop there because hardened grease and grit may be causing the crank to stick.

You must observe the position-of-wheels indicator, but this alone is like-wise not dependable. To make sure your wheels are down and locked, turn the crank as for as it will go, at which point you should feel a definite metal-to-metal indication. If the wheels are full down, the extended position lock will remove all possibility of the wheels retracting during your run-out.
Wildcat pilots have their share of those Dilbert accidents wherein no attempt whatsoever is made to lower the gear, and those cases where lowering of the wheels is not completed after having been interrupted for various reasons. If you make a practice of always going over your check-off list, double-checking your wheels, handle, contacting the tower and of glancing at the runway watch for a wheels-up indication, your chances of forgetting to crank your wheels down are infinitesimal.

The landing gear of this airplane must not be abused. If you make a heavy landing, be sure the gear is inspected before the plane is flown again. Some pilots seem to have adopted a sort of "G" method of lowering the gear, that is, unlatching the hand crank, then pulling the nose up to let the gear lower itself. This may result easily in damage to the operating mechanism, and it is definitely not recommended. Several cases of stripped gears have occurred after the hand crank tore out of the pilot's hand and the wheels "ran away." A properly adjusted friction brake, and a firm grip on the crank handle, prevent this type of accident.

Taxi Nose-Ups

The Wildcat has a very marked tendency to nose up, and must be treated accordingly. Accidents of this nature occur most frequently when you hit the slipstream of another plane, but sudden brakes and gusty crosswinds are also common contributory causes.

To avoid taxi nose-ups in the FM, you must use great care while taxiing behind other planes, particularly at the take-off position, and at other places where engines are being run up. Conversely, whenever you are running up your engine, take care to see that no Wildcat (or any other plane for that matter) is in a vulnerable spot behind you.

END

Probably more than anyone wanted to know.

Rich

I've noted a large number of landing related issues (or indications of such from a greater non-combat attrition rate) on F4F/Martlets in FAA service and it appears that the Sea Hurricane was actually less likely to crash when landing on.

 

[PStickney]

Believe it or not, the early Spitfire main gear track was 5 ft. 8 in., which was narrower than the Bf109's track of 6 ft. 5 in. which happened to be identical to the F4F's track at 6 ft. 5 in.

True - one big difference, however, is that when extended, both the Wildcat's and Spitfire's wheels were close to vertical. The BF-109, with its cantered wheels, will get into some weird self-steering action with any sort of roll. A lot of positive feedback there - sort of like the steering system for the front wheels of a Road Grader.
The deck angle that an airplane sits at is a big factor as well. The P-40 and F4U Corsair could be ground-looping beasts - until they lengthened the fuselage on the later P-40s, and extended the tailwheel leg on the Corsair.
Now I'm going to have to break out my straightedge and protractor.

 

[PStickney]

A very real man does it like that!
View attachment 829305

ANd then has to wait for a couple of weeks for the trucks with the takeoff trolleys and JATO Rocket Units to snake their way through the Allied Fighter-Bomber cover so that they could actually perform a mission after being forward deployed.
That's what happened to the Ar 234 Photo Recon Prototypes that were sent to Belgium (I think it was, offhand) during the Normandy Invasion, since conventional recon aircraft weren't going to get anything. Of course, getting to fly the first operational missions in July 1944 wasn't super productive.
"Wonderful pictures, really. But in order to find out where the Allies are, all I need is a telephone."

 

[MiTasol]

True - one big difference, however, is that when extended, both the Wildcat's and Spitfire's wheels were close to vertical. The BF-109, with its cantered wheels, will get into some weird self-steering action with any sort of roll. A lot of positive feedback there - sort of like the steering system for the front wheels of a Road Grader.
The deck angle that an airplane sits at is a big factor as well. The P-40 and F4U Corsair could be ground-looping beasts - until they lengthened the fuselage on the later P-40s, and extended the tailwheel leg on the Corsair.
Now I'm going to have to break out my straightedge and protractor.

As I said before from my perspective the problem on the 109 is not the canted wheels but the canted shock strut that changes the aircrafts track width as it/they compress and extend.

From what I can see the Wildcat had a worse landing accident rate that the Spit and 109 and the Wildcat is easiest to demonstrate how the track change affects the landing.

For the same reason the F4F/FM2 are very squirrelly on the ground. As you can see from the following factory blue print the wheels do not move straight up and down like on most aircraft (and this is almost true of the Spitfire) the Wildcat track changes considerably from the nominal 76.5 inch track (and the angle of the wheel to the ground also changes though far less). Don't ask me why the blueprint has the landing gear at an angle but the rest of the landing gear installation drawing horizontal. That is the manufacturers decision.
The sideways movement of each wheel from prior to touchdown to maximum oleo compression is just under 8 inches according to my scale rule.
That means the track actually varies close to 16 inches during maximum travel but, far more importantly for the poor blighter landing it if one main gear lands hard before the other touches (because the deck has tilted and/or a crosswind has tilted the aircraft and/or the pilot was just a little off on his approach) the the fuselage can lurch almost 8 inches to the opposite side as the one gear compresses. The pilot has virtually no way of counteracting this lurch and the inertia of the engine will keep the aircraft swinging that way which, unless he can catch it in time, will usually result in a ground loop on land and a visit to the catwalk on a carrier.

As the records in R Leonard 's post 597 show that was a very common accident on FM-2 and that also means on the F4F.

 

[GrauGeist]

True - one big difference, however, is that when extended, both the Wildcat's and Spitfire's wheels were close to vertical. The BF-109, with its cantered wheels, will get into some weird self-steering action with any sort of roll. A lot of positive feedback there - sort of like the steering system for the front wheels of a Road Grader.
The deck angle that an airplane sits at is a big factor as well. The P-40 and F4U Corsair could be ground-looping beasts - until they lengthened the fuselage on the later P-40s, and extended the tailwheel leg on the Corsair.
Now I'm going to have to break out my straightedge and protractor.

As I mentioned earlier, the Bf109's mainwheels had a positive camber (close to 25° as I recall) which influenced what is called "Lateral Force Variation".

Automobiles, like aircraft, are also influenced by LFV - this is why "Toe", "Caster" and "Camber" are key issues addressed in alignment.

The Spitfire and F4F, while having ground handling quirks of their own, did not have the added issues of the Bf109's due to having close to 0° camber.

 

[yulzari]

A difference between the Seafire accident rate and Martlet accident rate is the sheer strength of the fuselage. Many a Seafire landed 'safely' but the fuselage was over stressed and wrinkled becoming beyond shipboard repair. In Korea the FAA engineers chose to ignore the published Seafire damage limits to maintain the operational sortie rate.

One reason for HMS Unicorn was to have at least a Fleet capacity to repair more major damage at sea without impacting the operational carrier operations. A little shore bombardment from the four twin 4" guns was a minor icing on the cake. Even in peacetime carriers lose a lot of aeroplanes when operating at sea.

The Salerno Seafire landing cover was in the worst non storm conditions possible. Hot and windless with little room for carriers to make wind over the decks. Many Seafires were lost or damaged in the operation but maintained the cover over the landings and their accident rate was greatly exacerbated by operating outside their normal limits with landings at high speed and take offs at the margin for the weight with a full warload. Even the tough Martlet would have had a raised accident rate.

However it was the Martlet that was the preferred escort carrier fighter; last meeting modern Luftwaffe fighters in March 1945 with four Luftwaffe fighters downed. FWIW I used to know a wartime FAA pilot who considered the Sea Hurricane the best deck landing choice for bad North Atlantic/Arctic Ocean weather deck landing followed by the Barracuda.

He considered the Swordfish as cheating for a fleet carrier as a high wind speed and a fleet carrier at speed make it difficult to catch up with the carrier with a speed over the deck as a 'fast trot'. Jogging speed we might term it today. The biggest risk at a heaving sea at slow speed was having the Swordfish hit from below by 20,000 tons of ship suddenly pitching up as one reached the cut off point. He lost one of his friends when the fleet carrier had reports of U-Boats nearby and could not leave the fleet so progressed too fast for his friend and their crew to catch up with the carrier and they were lost ditching far from the fleet formation despite being in W/T contact and heading for the carrier's radio beacon.

 

[PStickney]

A difference between the Seafire accident rate and Martlet accident rate is the sheer strength of the fuselage. Many a Seafire landed 'safely' but the fuselage was over stressed and wrinkled becoming beyond shipboard repair. In Korea the FAA engineers chose to ignore the published Seafire damage limits to maintain the operational sortie rate.

One reason for HMS Unicorn was to have at least a Fleet capacity to repair more major damage at sea without impacting the operational carrier operations. A little shore bombardment from the four twin 4" guns was a minor icing on the cake. Even in peacetime carriers lose a lot of aeroplanes when operating at sea.

The Salerno Seafire landing cover was in the worst non storm conditions possible. Hot and windless with little room for carriers to make wind over the decks. Many Seafires were lost or damaged in the operation but maintained the cover over the landings and their accident rate was greatly exacerbated by operating outside their normal limits with landings at high speed and take offs at the margin for the weight with a full warload. Even the tough Martlet would have had a raised accident rate.

However it was the Martlet that was the preferred escort carrier fighter; last meeting modern Luftwaffe fighters in March 1945 with four Luftwaffe fighters downed. FWIW I used to know a wartime FAA pilot who considered the Sea Hurricane the best deck landing choice for bad North Atlantic/Arctic Ocean weather deck landing followed by the Barracuda.

He considered the Swordfish as cheating for a fleet carrier as a high wind speed and a fleet carrier at speed make it difficult to catch up with the carrier with a speed over the deck as a 'fast trot'. Jogging speed we might term it today. The biggest risk at a heaving sea at slow speed was having the Swordfish hit from below by 20,000 tons of ship suddenly pitching up as one reached the cut off point. He lost one of his friends when the fleet carrier had reports of U-Boats nearby and could not leave the fleet so progressed too fast for his friend and their crew to catch up with the carrier and they were lost ditching far from the fleet formation despite being in W/T contact and heading for the carrier's radio beacon.

One of the big reasons why the Wildcat stayed in service particularly for the Escort Carriers was that, with all its quirks, it was "Good Around the Boat". Leroy Grumman was an early Naval Aviator, and know that the biggest danger that a Naval Aviator faced was getting off the ship, and getting back on, and he was willing to lose a bit of peak performance to give that edge.

 

[PStickney]

As I said before from my perspective the problem on the 109 is not the canted wheels but the canted shock strut that changes the aircrafts track width as it/they compress and extend.

From what I can see the Wildcat had a worse landing accident rate that the Spit and 109 and the Wildcat is easiest to demonstrate how the track change affects the landing.

For the same reason the F4F/FM2 are very squirrelly on the ground. As you can see from the following factory blue print the wheels do not move straight up and down like on most aircraft (and this is almost true of the Spitfire) the Wildcat track changes considerably from the nominal 76.5 inch track (and the angle of the wheel to the ground also changes though far less). Don't ask me why the blueprint has the landing gear at an angle but the rest of the landing gear installation drawing horizontal. That is the manufacturers decision.
The sideways movement of each wheel from prior to touchdown to maximum oleo compression is just under 8 inches according to my scale rule.
That means the track actually varies close to 16 inches during maximum travel but, far more importantly for the poor blighter landing it if one main gear lands hard before the other touches (because the deck has tilted and/or a crosswind has tilted the aircraft and/or the pilot was just a little off on his approach) the the fuselage can lurch almost 8 inches to the opposite side as the one gear compresses. The pilot has virtually no way of counteracting this lurch and the inertia of the engine will keep the aircraft swinging that way which, unless he can catch it in time, will usually result in a ground loop on land and a visit to the catwalk on a carrier.

As the records in R Leonard 's post 597 show that was a very common accident on FM-2 and that also means on the F4F.

View attachment 830394


View attachment 830382

View attachment 830383

A good point - another issue I've heard described (Nobody's going to let me fly their Wildcat) is that the rather "Soft" rebound ratio in the struts would cause one wing or the other to dip as the strut on one side or the other compressed. Not that big an issue in an arrested landing, but on a runway, or while taxiing, I can see it causing a reaction from the pilot that gets things into trouble.

 

[Admiral Beez]

I wonder if the IJNAS considered trialing the Hellcat on their carriers. In better fettle of course.

 

[SaparotRob]

First "beute" Hellcat picture I've ever seen.

 

[GrauGeist]

I wonder if the IJNAS considered trialing the Hellcat on their carriers. In better fettle of course.


View attachment 831306

The IJN had the J2M3, which was comparable.

 

[tyrodtom]

The IJN had the J2M3, which was comparable.

Was the J2M3 carrier capable ?

 

[Greg Boeser]

No. It was developed as a land based interceptor. The "J" in J2M.

 

[Admiral Beez]

Was the J2M3 carrier capable ?

I was more thinking of Japan's thoughts on a folding wing fighter. Japan's designers might never have possessed a folding wing fighter for in-depth inspection before.

 

[GrauGeist]

I was thinking along the lines of the J2M being comparable to the F6F in performance.

As an aside, yes, the J2M was designed as a land-based fighter, but the N1K, which was initially designed as a floatplanes (as denoted by the "N" prefix) did have a land-based variant which even included a carrier-based prototype.

 

[Admiral Beez]

As an aside, yes, the J2M was designed as a land-based fighter, but the N1K, which was initially designed as a floatplanes (as denoted by the "N" prefix) did have a land-based variant which even included a carrier-based prototype.

There's also the Aichi M6A. Keep the folding wings but with further outward pivots, replace the floats with retractable undercarriage.

 

[SaparotRob]

The Seiran is gorgeous and I love it. With that said, wasn't it a bit of a light weight? As I haven't penciled in any research time for today, I can't qualify saying you might as well use A5Ms.

 

[GrauGeist]

There's also the Aichi M6A. Keep the folding wings but with further outward pivots, replace the floats with retractable undercarriage.

The M6A1-K had all the features of the M6A1, but had retractable main gear.

 

[Admiral Beez]

The M6A1-K had all the features of the M6A1, but had retractable main gear.

No wing fold, IIRC. There's no place to put the undercarriage.