Admiral Beez
Major
The Seafire gets criticized its narrow track undercarriage, but is this fair? The Grumman Wildcat's similarly narrow.
Was the Seafire’s narrow track the issue?
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GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
I think the problem with the Seafire's maingear, is that it took several marks before the land-based maingear was adapted to naval specs.
In other words, the gear was designed for land-based operations unlike the F4F/Martlet.
Being a narrow track wouldn't have been much of a problem but the oleo's action would (too firm, too soft, etc.).
In other words, the gear was designed for land-based operations unlike the F4F/Martlet.
Being a narrow track wouldn't have been much of a problem but the oleo's action would (too firm, too soft, etc.).
Eric Brown:
(After extolling the type's virtues) It was in the critical area of deck landing that the Seafire had significant shortcomings. The view on the approach was poor. Speed control was difficult because the airplane was underflapped and too clean aerodynamically. Furthermore, landing gear had too high a rebound ratio and was not robust enough to withstand the high vertical velocities of deck landing.
(After extolling the type's virtues) It was in the critical area of deck landing that the Seafire had significant shortcomings. The view on the approach was poor. Speed control was difficult because the airplane was underflapped and too clean aerodynamically. Furthermore, landing gear had too high a rebound ratio and was not robust enough to withstand the high vertical velocities of deck landing.
No, the Seafires problem was the arrester gear caused the nose to pitch violently down when it caught the wire causing the struts to fully compress and throw it back into the air before the wire then slammed it back onto the deck breaking the landing gear, look at the photo's of Seafire crashes and notice the nose is berried into the deck on most of them seafire carrier landing - Google Search
The track was never the issue. The fundamental problem was that the original Spitfire undercarriage was designed for grass airfield landings in which cross winds would rarely be an issue, there would be a low vertical velocity at touch down with 'wheeler' landings allowing a decent forward view over the nose. The Spitfire was designed to land at a maximum vertical velocity of just seven feet per second, anything ore than that and the undercarriage would break. Carrier aircraft were usually designed for almost double this figure, the Corsair undercarriage was designed to handle a vertical rate of descent of twelve feet per second, but was obviously much heavier. In the case of the Spitfire, why would Mitchell design a heavy, robust undercarriage that was used for a few seconds of each flight and was useless baggage the rest of the time?
Landing on a carrier almost none of the above applied. The aircraft was simply not designed for carrier operation. There were many issues as a result, but the question pertains to the undercarriage. Making a 'wheeler' landing on a grass aerodrome at speeds well above the stall allowed a good view forward, good directional control after landing and placed the landing loads vertically up the undercarriage legs, where Mitchell intended them to be. It worked well for RAF pilots.
In the case of stalled three point landings*, which is essentially what a carrier landing was, there is a bending component to the loads. This tended to wrench the attachment points free from the spar and collapse the undercarriage. Deck landings were always made in a three point posture at which attitude the wing was at stalling incidence, about 15 degrees. There's not much to be done about that, it is a function of the design of the aircraft, but it had nothing to do with the undercarriage track.
The Seafire suffered an appalling accident rate but what is truly remarkable is that some pilots managed to land them on carriers in a fashion that allowed them to be flown again.
*The Seafire landed at a mere 1.05 Vse, just three knots above the engine on stall speed, a much smaller margin than that for aircraft designed for carrier operations which typically landed at something like 1.25 Vse. Such a small margin was extremely difficult to maintain, as Eric Brown noted. It was much easier to accelerate a Seafire than to decelerate, giving a rather lopsided speed control, which meant that the entire final approach had to be flown just a few knots above the stalling speed. To make it even harder the ASI represented 10 knots with about 1/8" of needle travel!
Land any faster and the Seafire would not hit the deck in a three point attitude at the required three and a half degree descent angle. When the main wheels were first to hit the deck they would push the nose up (because they are forward of the CoG) while the tail was still descending. This obviously increased the incidence of the wing, and lift, and the aircraft would bounce back into the air and float in ground effect into the barrier two or three seconds later. This is what Fleet Air Arm pilots referred to as 'Float, float, prang'.
Landing on a carrier almost none of the above applied. The aircraft was simply not designed for carrier operation. There were many issues as a result, but the question pertains to the undercarriage. Making a 'wheeler' landing on a grass aerodrome at speeds well above the stall allowed a good view forward, good directional control after landing and placed the landing loads vertically up the undercarriage legs, where Mitchell intended them to be. It worked well for RAF pilots.
In the case of stalled three point landings*, which is essentially what a carrier landing was, there is a bending component to the loads. This tended to wrench the attachment points free from the spar and collapse the undercarriage. Deck landings were always made in a three point posture at which attitude the wing was at stalling incidence, about 15 degrees. There's not much to be done about that, it is a function of the design of the aircraft, but it had nothing to do with the undercarriage track.
The Seafire suffered an appalling accident rate but what is truly remarkable is that some pilots managed to land them on carriers in a fashion that allowed them to be flown again.
*The Seafire landed at a mere 1.05 Vse, just three knots above the engine on stall speed, a much smaller margin than that for aircraft designed for carrier operations which typically landed at something like 1.25 Vse. Such a small margin was extremely difficult to maintain, as Eric Brown noted. It was much easier to accelerate a Seafire than to decelerate, giving a rather lopsided speed control, which meant that the entire final approach had to be flown just a few knots above the stalling speed. To make it even harder the ASI represented 10 knots with about 1/8" of needle travel!
Land any faster and the Seafire would not hit the deck in a three point attitude at the required three and a half degree descent angle. When the main wheels were first to hit the deck they would push the nose up (because they are forward of the CoG) while the tail was still descending. This obviously increased the incidence of the wing, and lift, and the aircraft would bounce back into the air and float in ground effect into the barrier two or three seconds later. This is what Fleet Air Arm pilots referred to as 'Float, float, prang'.
- Thread starter
- #6
Admiral Beez
Major
Good points. To be fair though, Not all Seafire landings are prangs
The answer probably would have been an air brake that was deployed during landing with additional power on during landing. If power was reduced the aircraft would then rapidly deaccelerate. If acceleration was required the engine could be increased or the dive brake retracted. Such a solution was in fact used to deal with a different problem known as 'sabre dance' that occurs in swept wing aircraft. The Me 109T I believe used spoilers to solve the issue.
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- #8
Admiral Beez
Major
Was any of this fixed in the later versions? The Seafire was sent to Korea. Could the improvements of the later versions have been realistically incorporated into those of 1942-45?
One would think bigger carriers, a faster approach speed and a stronger arrestor hook would help.
buffnut453
Captain
As with all aircraft, we need to be careful about lumping together different marks and tarring them all with the same brush. Certainly, the early versions had the problems indicated. The Seafire F Mk III entered service in late 1942 was the first truly operationally viable variant to include properly strengthened undercarriage and folding wings. I believe most of the issues with the undercarriage had been resolved by then.
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- #11
Admiral Beez
Major
The later versions used on the smaller and slower Majestic/Colossus class CVLs had their arrestor hook relocated to the tail. Perhaps that helped.
Mike Crosley was not impressed with the Seafire III. he devotes an entire chapter to the effects of instability on various aspects of flight. In the section under 'deck landings' he remarks on its tendency to float 'serenely' over the wires.
"When the pilot cut the power and the slipstream speed reduced, the extra lift given by the positive angle on the elevator also reduced. The tail then lost a great deal of its lift and it too fell - without the pilot doing a thing. As this was equivalent to the pilot pulling back on the stick, in that it increased mainplane incidence and lift, and thus 'float', he always got the blame. It was a case of the 'V Squared' law making a much larger reduction in lift on the tailplane than on the mainplane, when the slipstream over the tail surface fell from perhaps 100 mph during a power-on approach, to about 50 mph after the 'cut'. The reason this did not occur to other aircraft was that there is 'negative lift' on a stable aircraft's tail surfaces, particularly when they are in the landing configuration, so that the 'cut' merely produces a nose down pitch, if any."
Emphasis in the original.
The Seafire III was still a victim of the original aerodynamics of an aircraft designed to land on grass aerodromes, and the aerodynamic compromises made as the aircraft was developed.
The first Seafire to really overcome many of the problems was the Seafire 47. The contra-rotating propellers cured many of the problems of the Seafire XV, which killed many of its pilots. Crosley notes that among the issues finally cured were, aileron reversal, the swing and wing stalling on take off and on going around (bolting for our US readers). Furthermore it required no trimming in the dive and became an excellent rocket and gunnery platform because aiming errors due to skid caused by propeller gyroscope and slipstream yaw effects were eliminated. All Griffon engined Seafires had a CoG further forward which cancelled the need for 'positive weight' and other dangerous palliatives intended to cure instability problems. The heavier engine allowed bigger tail surfaces and finally the Seafire got a sting hook which hung much lower than the original A frame (with its tendency not to lock even after picking up a wire). Unfortunately, an aircraft that did not enter squadron service until early 1948 is hardly relevant to WW2.
"When the pilot cut the power and the slipstream speed reduced, the extra lift given by the positive angle on the elevator also reduced. The tail then lost a great deal of its lift and it too fell - without the pilot doing a thing. As this was equivalent to the pilot pulling back on the stick, in that it increased mainplane incidence and lift, and thus 'float', he always got the blame. It was a case of the 'V Squared' law making a much larger reduction in lift on the tailplane than on the mainplane, when the slipstream over the tail surface fell from perhaps 100 mph during a power-on approach, to about 50 mph after the 'cut'. The reason this did not occur to other aircraft was that there is 'negative lift' on a stable aircraft's tail surfaces, particularly when they are in the landing configuration, so that the 'cut' merely produces a nose down pitch, if any."
Emphasis in the original.
The Seafire III was still a victim of the original aerodynamics of an aircraft designed to land on grass aerodromes, and the aerodynamic compromises made as the aircraft was developed.
The first Seafire to really overcome many of the problems was the Seafire 47. The contra-rotating propellers cured many of the problems of the Seafire XV, which killed many of its pilots. Crosley notes that among the issues finally cured were, aileron reversal, the swing and wing stalling on take off and on going around (bolting for our US readers). Furthermore it required no trimming in the dive and became an excellent rocket and gunnery platform because aiming errors due to skid caused by propeller gyroscope and slipstream yaw effects were eliminated. All Griffon engined Seafires had a CoG further forward which cancelled the need for 'positive weight' and other dangerous palliatives intended to cure instability problems. The heavier engine allowed bigger tail surfaces and finally the Seafire got a sting hook which hung much lower than the original A frame (with its tendency not to lock even after picking up a wire). Unfortunately, an aircraft that did not enter squadron service until early 1948 is hardly relevant to WW2.
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- Thread starter
- #13
Admiral Beez
Major
Given a Merlin instead of the Griffon and a three blade prop instead of the contra-rotating, can we get to a reasonably safe Seafire design whilst still producing it alongside the Spitfire? Moving the hook to the tail and improving the damping of the suspension would be a good start, but there's still the low speed handling issues. What about larger flaps?
And to be fair the F4F suffered because of it's narrow track, especially when used from shore bases.
I suspect the best 'Seafire' design would have been a Sea Hurricane with a less draggy wing and a Merlin 24 engine.
Clayton Magnet
Staff Sergeant
- 902
- Feb 16, 2013
That might just increase the tendency to float, unless some "split" type flaps could be fitted. Perhaps spoilers would be more effective?
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- #17
Admiral Beez
Major
Or a Typhoon with relocated radiator, reliable Sabre and a tail that doesn't tear off.
That would be a Centaurus then, or an Eagle. With a lightened airframe it could be quite a good performer, but should be called by another name, like Fury.
Clayton Magnet
Staff Sergeant
- 902
- Feb 16, 2013
And a navalized version could be called "Sea Fury", hypothetically, of course
- Thread starter
- #20
Admiral Beez
Major
The thick-winged version... we'll call it the Hawker Tornado. Seen below in I believe 1940.And a navalized version could be called "Sea Fury", hypothetically, of course
