SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
Effective camo. I didn't even notice the tail.
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Effective camo. I didn't even notice the tail.Seems to be a FM-2.
Seems to be a FM-2.
In the example in the picture, the wingtips meet just above the cockpit. Wings folding closer to the fuselage than halfways in, will result in the tips meeting higher up, and thus require a higher hangar. Unless you're Grumman.As a structural engineer, I would want to place the fold as far out as possible, given that the weight of the fold and lock fittings will increase dramatically the further inboard you do the fold. I don't know why, but I would guess the folds on the Zero's wings was done solely to make it fit on the carrier's elevator system.
But I guess the crew chiefs and carrier operations officers could be inclined to argue for a fold further in to fit more of them on the carrier. But I would think that that would have been part of the requirement spec from the beginning in that case. But given where they put the fold it probably wasn't. But if the customer wants the fold at the wing root, well then that would be where I would put it. Because the customer is always right isn't he?
In the example in the picture, the wingtips meet just above the cockpit. Wings folding closer to the fuselage than halfways in, will result in the tips meeting higher up, and thus require a higher hangar. Unless you're Grumman.
Wing tips aside, the non-folding wing on the A6M was such as wasteful use of hangar space. The only bespoke (vs. converted land-based aircraft) monoplane, retractable undercarriage carrier fighters without folding wings I can think of are the Brewster Buffalo and the A6M. I suppose there's also the early F4Fs, but they switched to folding asap. I wonder what Jiro Horikoshi would have designed if he was required to include folding wings. Maybe he could reduce the A6M's superlative endurance as this seems superfluous.For sure, the B5N fold saves a lot of space in the hangar and means you can get it up and down a smaller elevator. Maybe the B5N was designed to fit on smaller elevators on other carriers or simply to save space? Who knows? But looking at the attached picture of the Hiryu's elevators, it looks like the elevators were of different size and the Zero's fold was done to make it "elevatorable" on smaller type elevators.
View attachment 829377
Considering there were only 3 navies in the world building "bespoke" carrier fighter planes of any type in 1939/40 (and the F4F was using fixed wings at the time) then the fixed wing was the 'standard' of the day. It took time to get into folding wings.The only bespoke (vs. converted land-based aircraft) monoplane, retractable undercarriage carrier fighters without folding wings I can think of are the Brewster Buffalo and the A6M. I suppose there's also the early F4Fs, but they switched to folding asap.
Perhaps Nakajima had the manpower to design the folding wing. Put a thinner version of their B5N's folding mechanism onto their Ki-43 Hayabusa. Thought it seems that every Japanese fighter is designed around a monolithic, single piece wing.I believe Jiro designed the A6M's fold using the most minimal calculations.
In 1939-40? No. Keep it fixed wing like the F4F. But by 42-43, yes, like how the F4F (and even the Seafire) moved to folding wings.Now you want it to fold into a smaller space below deck?
Because it is the lightest way to design a wing.Thought it seems that every Japanese fighter is designed around a monolithic, single piece wing.
I believe Jiro designed the A6M's fold using the most minimal calculations.
Having the fold placed at the maximum allowable width, means less reinforcing which in turn means less of a weight penalty.
The tips could also be easily moved by ground crew, eliminating the need for a hydraulic system and the weight that it would add to the airframe.
Wouldn't that be the "Hamp"?
Didn't know that. But now that you mention it, it looks pretty narrow on the Spitfire as well. Wonder why we hear about so many problems on the BF 109 but not the Spitfire?.......
The ground handling issues stem from the gear geometry and extreme camber of the tire's contact with the ground.
To at least partly exonerate the poor pilots, it must be stated that most of these FMs had to operate on and from the restricted decks of Escort Carriers.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