Sea Hurricane and the prohibitive weight of folding wings

[PFVA63]

Hi,
I wonder if the canon armament of later Hurricanes might add a bit of complexity with regards to any existing concepts there may have been for folding wings for earlier marks of the plane?
Pat

 

[ThomasP]

Hey PFVA63,

When I did the drawings mentioned above, I used the 'C' wing internal structural views to check if a simple break-wing fold was feasible at the point where the outer wing is fastened to the inner wing. I used a large load-bearing aluminum casting (using what today is included in the 2000 series alloy) to replace the mating end structures/surfaces of each of the wing sections. I did not see any reason why the 'C' wing would cause any problems. Incidentally, for my version of the SeaHurricane I replaced the armament with the standard Spitfire outfit of 1x 20mm and 2x .303 in each wing. This decreased the armament installation weight by about 80 lbs and allowed the ammunition load to be increased to 180 rpg for the 20mm, giving it the ~same firing time as for the .303 cal MG with 330 rpg.

 

[nuuumannn]

The Sea Hurricane was always intended as a stopgap measure so the resources and will power to design folding wings just weren't there.

Note that at that same time Hurricanes were being mounted on CAM merchant ships, a use in which they were considered to be expendable.

These pretty much nail why not more effort was put into the Sea Hurricane regarding folding wings in service. In fact, the Hurricane on CAM ships was the first incarnation of the Hurri at sea and was initially a conversion of war weary Mk.Is. These were operated by the RAF, not the navy and a training unit was established at Speke especially for the purpose. The inclination to put the Hurricane on carriers was simply an expedient until the Firebrand was ready, which wasn't promised until early 1942, besides, Cam was already working on the Sea Typhoon (P.1009), which was intended as a back-up in case the Firebrand wasn't ready in time. Even then, the Sea Typhoon was promised until early to mid 1942.

Onvce the decision was made to finally give the FAA the Sea Spitfires it had wanted since before the war, the fate of the Sea Hurricane as an ongoing project was sealed. Although in saying all that, I'm pretty certain that given the inclination, Hawker would have been able to do it without too much impact on the Hurri's performance. If the Sea Typhoon drawings that survive are anything to go by, the wing would have folded to sit along the fuselage side, with the leading edge up.

 

[MIflyer]

The USAF used to put an "O" in front of the serial number of aircraft in service over 10 years old; that stood for "obsolete.."

 

[pbehn]

Military aircraft are made obsolete by the opposition.

 

[MIflyer]

According to the book "The Seafire: the Spitfire that Went to Sea" the Seafire III folding wings added 125 lb to the structure.

 

[MIflyer]

Maybe the reason the Sea Typhoon never got anywhere was the discovery that Typhoon basically could not ditch with any significant probability that the pilot would survive.

And the poor ditching characteristics were not due to that big radiator scoop. As one Typhoon/Tempest pilot pointed out, the Tempest had the same scoop and ditched just fine. Something about the wing of the Typhoon caused it to act like the Flying Sub.

"Military aircraft are made obsolete by the opposition."

Which includes bureaucrats on the same side.

 

[Admiral Beez]

Maybe the reason the Sea Typhoon never got anywhere was the discovery that Typhoon basically could not ditch with any significant probability that the pilot would survive.

And the poor ditching characteristics were not due to that big radiator scoop. As one Typhoon/Tempest pilot pointed out, the Tempest had the same scoop and ditched just fine. Something about the wing of the Typhoon caused it to act like the Flying Sub.

"Military aircraft are made obsolete by the opposition."

Which includes bureaucrats on the same side.

The radiator could be moved if necessary, like on the Hawker Tornado below. I don't see what in the wing would make it a bad ditcher.

 

[MIflyer]

Yes, but a pilot who flew both Typhoon and Tempest in combat and actually managed to ditch a Typhoon and survive said the Tempest ditched fine but the Typhoon was a deathtrap, and the difference was the wing. The Tempest wing was much thinner than the Typhoon's, although the significance of that relative to ditching escapes me.

He managed to ditch a Typhoon damaged over France in the Channel by getting things set up just right and dragging the tail first. He had a lot of time to prepare while it was still flying and had many hours in Typhoons, both as ferry pilot and in combat.

When it came to getting hit over France and making it back home it seems that the Whirlwind was better than the Typhoon - even though the props on the Whirlwind would not feather.

 

[Admiral Beez]

When it came to getting hit over France and making it back home it seems that the Whirlwind was better than the Typhoon

Having a second engine, even without feathering a disabled one, likely improved one's chances.

It must have been harrowing to land a single engine Whirlwind with the drag on one side and a Peregrine running full tilt on the other, with the added concern of a lack of fuel tank sharing dramatically reducing range whilst leaving a half full and heavy tank on the damaged side.

It's an odd thing that Petter didn't include a fuel bypass or sharing valve. Was this a common omission in British twin-engined aircraft of the era? Did the Mosquito or Blenheim have the ability to share fuel between engines?

 

[MIflyer]

Yes, and often as not the one that was not turnin' was burnin' for at least part of the trip. But I guess maybe the Whirlwind could be ditched with more success than was typical for the Tiffie.

Not having featherable props sounds like an unacceptable situation but it seems that was the norm for British built aircraft in the RAF until about the middle of 1942. The Manchester was the only British built twin engined aircraft in that time frame that had featherable props. That was the reason they chose the Manchester to simulate a glider trying to slip past the radar; they could feather both props and have a good chance of surviving it.

 

[fubar57]

 

[Kevin J]

My thoughts are as follows. It's not until Italy enters the War, the Germans gain bases in Norway, the West Coast of France, and the IJN deploy the Zero in China that it becomes clear that a Sea Hurricane is required. The Sea Gladiator is a match for the A5M, Cr 42, the Skua for the early Ju 87B Stuka, Ar 196 and Cr 32. The Fulmar for the A5M, Cr 42. So starting Summer 1940, you develop a Sea Hurricane, no FW. Introduction January 1941 is about right. You need an interim folding wing fighter so buy the Martlet I/II because a Spitfire I/II with arrestor hook and catapult spools maybe FW will probably only do about 335 mph, same as the F4F-3/4. A Sea Hurricane with a FW, perhaps arrives mid 1942, same speed as Martlet IV, deployed later in 1942. So you don't need a FW Sea Hurricane. The only way you get a Sea Hurricane earlier if Richard Sorge is working for UK and we know about Zero when it first flies, France isn't defeated in 1940 and Italy remains neutral.

 

[K5083]

I don't think production decisions usually depended on ditching characteristics.

Sir Sydney Camm (and he should know) reckoned that the naval gear, folding wings, strengthening, catapult points and hook cost 500lb on the Sea Fury. I guess it would be less on a fully-navalised Sea Hurricane but that aircraft was a stop-gap and I suppose the extra time and trouble of doing the wing was considered unnecessary.

 

[Admiral Beez]

I don't think production decisions usually depended on ditching characteristics.

Sir Sydney Camm (and he should know) reckoned that the naval gear, folding wings, strengthening, catapult points and hook cost 500lb on the Sea Fury. I guess it would be less on a fully-navalised Sea Hurricane but that aircraft was a stop-gap and I suppose the extra time and trouble of doing the wing was considered unnecessary.

Lipstick on a pig by now, but would the Griffon have helped the folding-wing Sea Hurricane regain sufficient performance?

 

[xylstra]

Interesting note about concern over the added weight of a folding wing mechanism.

"The provision of a folding wing was examined in 1940. But the desperate need for aircraft designers for next-generation aircraft, as well as concerns over the Hurricane's ability to accommodate the extra weight, soon saw this idea abandoned. " http://www.armouredcarriers.com/hawker-sea-hurricane-variants

I didn't think the Hurricane was considered nearly overweight in standard spec. Did the Seafire or Wildcat gain a lot when the fold was added?

Seafire
Seafire Mk IIc with 36 ft 10 in wingspan, 2x20mm 4x.303, and Merlin 46. Empty weight 5,300 lb (2,404 kg)
Seafire Mk. III with folding wings, 32 ft 2 in wingspan, and Merlin 55M. Empty weight: 5,450 lb (2,472 kg)

By shortening the wingspan, the weight between the two Seafires goes up by only 150 lbs. IDK how much of this 150 lb. increase is due to the engine upgrade.

Would the Sea Hurricane really have become overweight if folding wings were added? Mind you, the Hurricane IIc weighs 5,745 lb (2,606 kg) empty - by the time the Seafire got near that empty weight it was Griffon-powered.

I think the question is a little mis-directing. It's not so much a question of overall weight increase (within reasonable limits) but rather, the distribution of any additional weight. Concentration of the latter outboard in the wing may adversely affect the aircraft's roll-rate in turn limiting the aircraft's combat manoeuvrability - disastrous for a fighter!

 

[GreenKnight121]

I think the question is a little mis-directing. It's not so much a question of overall weight increase (within reasonable limits) but rather, the distribution of any additional weight. Concentration of the latter outboard in the wing may adversely affect the aircraft's roll-rate in turn limiting the aircraft's combat manoeuvrability - disastrous for a fighter!

Which is one reason Leroy Grumman wanted a fold that was right next to the fuselage... unlike the fold-points on aircraft with upward-folding wings (which mostly had wide-set landing gear).

 

[jetcal1]

Lipstick on a pig by now, but would the Griffon have helped the folding-wing Sea Hurricane regain sufficient performance?

New engine and cooling system, re-stressed airframe? Me thinks it's called a Tornado.

 

[yulzari]

Lipstick on a pig by now, but would the Griffon have helped the folding-wing Sea Hurricane regain sufficient performance?

Well Hawkers did the design for putting a Griffon in a Hurricane. If the Sea Hurricane became the standard Admiralty fighter it would be a way to keep it in service with minimum production line changes rather than a new type. Not advocating it but if the Sea Hurricane began pre war it would just be another (major) update and it was the Admiralty who wanted the Griffon in the first place.

 

[K5083]

If we're goimg to re-engine the Sea Hurricane, why not the Bristol Hercules? Available at 1400hp+ in the right timescale, and air-cooled for those long waits on deck. I know Hawker looked at a herc-hurricane, but I don't know why they didn't at least fly a test bird.