Improved Skua for FAA?

Shortround6 said:

You can blame the government at least partly.

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To a point. The specification offers parameters, it doesn't stipulate design cues. N.11/40 did stipulate the use of the Sabre in a power egg arrangement. Blackburn was solely responsible for the design and structural elements of the Firebrand. The only competitor was the Hawker P.1009 Sea Typhoon, which would have been problematic too based on the work required on the Typhoon as it happened, with detachable rear fuselage and high ingress of carbon monoxide into the cockpit, to say nothing of the issues with the Sabre, which, to be fair were not fully understood at the time the specification was written.

Admiral Beez said:

So, do we think Petter seconded to Blackburn in 1936 can help the Skua?

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Not by much, design is almost certainly completed that year and the aircraft is well on the way to receiving a production contract, which took place in 1936. If you want Petter to go in, get him in sooner to aid in design cues. He could have made it smaller for starters, but whatever the choices he makes, they'd be advanced. Whether they'd be practicable or not in the real world remains to be seen, he was definitely a thinker, but if the Whirlwind is anything to go by he would overthink things. However, the Lysander was an entirely conventional aircraft, which means he could have gone down that route...

Admiral Beez said:

I can't think of any other carrier aircraft made by Blackburn that wasn't rubbish. I suppose the Ripon, Baffin and Dart deserve some kudos.

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I mentioned this earlier, the Dart through to the Shark were equal to if not better than foreign contemporaries on carrier decks. These aircraft were largely the work of Maj F.A. Bumpus, who was the chief engineer at Blackburn, with George Petty as his assistant between the Great War and WW2. Petty took over from Bumpus in 1937, although was given lead on the design of the Skua. Bumpus had worked with Robert Blackburn himself as well as Admiralty personnel during and subsequent to the Great War, so he had a handle on what the navy expected from its aircraft designs. The outlandish Blackburd was designed by Harris Booth of the Admiralty Air Department, so Bumpus can't be held responsible for that, but his were generally sound workable designs.

Petty took design duties of the Skua and was responsible for the Botha, a terrible aeroplane, which, Petty did believe was underpowered at the time of design and suggested to the Air Ministry that the Hercules should be its powerplant, not the Perseus, but this was turned down, although investigative work was done on the Botha II powered by Hercules. Probably still would have been bad. Once again, Petty was responsible for the Firebrand and Firecrest. I'm sensing a pattern here...

Interesting to note that the Buccaneer was designed by B.P. Laight.

Macandy said:

The rebuilt Essex class were fitted with a 1.5" steel flight deck, not because they 'wanted to mimic' the Illustrious design, it was simply needed as a strength deck to operate the much heavier jets.

The Midway design was a disastrous dead end, terrible ships with an awful and vicious roll thanks to being so top heavy with the pointless heavy armoured deck.

No US carrier after the Midway dead end used an armoured flight deck. They all use steel strength decks of 1.5"-2", a simple design requirement due to their huge size.

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CV-41 Midway before her 1967-70 second modernization had no rolling issues.

CV-42 FDR had no rolling problems at any time in her career... neither did CV-43 Coral Sea.

GreenKnight121 said:

CV-41 Midway before her 1967-70 second modernization had no rolling issues.

CV-42 FDR had no rolling problems at any time in her career... neither did CV-43 Coral Sea.

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Right from the start, the class proved to be very cramped and wet ships, seriously overweight, and with a nasty snap roll in any seaway thanks to all that top weight.
That roll never got better, only worse. The design was quickly discarded and the Forrestal Class were clean paper designs with lighter and stronger, but bigger hulls,

Hey Macandy,

I think you are getting her post-1966/70 rebuild seakeeping issues confused with her handling qualities as built.

As built, she had no problematic roll - nasty or otherwise. The top weight you are referring to (ie armoured flight deck) was taken into account in her original design, and as completed her period of roll under all normal conditions was considered good.

As far as being wet goes. As built she had a lower freeboard than the follow-on supercarriers, so if you are saying that she was wetter compared to the later supercarriers then you are correct. But her freeboard as built was comparable to her predecessors and contemporaries.

Some freeboards (height from WL (Water Line) to FD (Flight Deck)
Illustrious CV as built ~42'
Independence CVL as built ~45'
Essex class CV as built ~55'
Enterprise/Yorktown CV ~55'
Midway class CVB as built ~53'

As far as being cramped goes. She was built with the ability to carry over 130 aircraft, but she only ever carried that many on her first operational deployment to the Med in 1947. Before her 1955/57 rebuild she normally operated around 80-90 aircraft, the same as for the Essex class during most of WWII. (80 aircraft was the ~size of a normal carrier air group at the time.)

Edited

Wetness represents an interesting issue for the Midways.

According to Friedman "US Aircraft Carriers. An Illustrated Design History", it was recognised well before the Pacific Fleet encountered the June 1945 typhoon, which damaged the flight decks of several carriers, that the Midways would be wet. This was due to their length in proportion to their freeboard. Added to that, as completed they rode lower in the water than initially planned as they were badly overweight due to all the extras added during their build (especially 40mm & 20mm AA guns, radars etc). But that was a problem common to most of the warship classes designed up to the early wartime years. If only ship designers could have foreseen the explosion in topweight for more guns, radar and in the case of carriers, aircraft.

But he makes no mention of rolling being a problem during the early part of their careers.

Photo of Midway in a Med gale.


CVB-43 Coral Sea being less advanced in her build was modified to extend her side plating up to meet the underside of the forward flight deck and had a transverse bulkhead installed to link the side plating up. This was later applied to the other two ships. Note this is not the Hurricane bow fitted in the 1950s modernisations. CVB-43 also completed with only 14 of 18 5"/54 AA guns in a weight reduction effort. Changes to her bow are visible here.


Another thing to bear in mind is that these ships operated in the Atlantic initially (it was 1954 before any of them ventured into the Pacific as they were too wide for the Panama Canal at that time) with its generally rougher weather than US fleet carriers encountered in the Pacific during WW2.

Friedman goes on to say:-
"The ships were also wet, both on the hangar and the flight decks. For example, they tended to plunge into heavy seas rather than ride over them, so that green water broke over the forward end of the flight deck. The latter was leaky, making the hangar deck wet in the rain as well as in heavy seas. Flight deck wetness was particularly significant because US operating practice required aircraft to be parked for extended amounts of time at the forward end of the flight deck."


As for them being cramped, well that was a sign of the times. All navies found that crew sizes grew significantly during WW2. Midway was still a 1941 design although she didn't complete until 1945. Designed for a total complement (ship & air) of 3,583, by 1947 this had grown to about 4,100 with more in prospect as jets and new weapons came across the horizon. And much of that accomodation was on the gallery deck which increased the need for air conditioning in tropical climes, being under the Armoured flight deck. The latter was also a problem encountered by the British Armoured carriers in the tropics during WW2 and especially for Victorious after her reconstruction.

The real problem with carriers however is not the height of the flight deck above the waterline, but the height of the hangar deck above the waterline. If water, whether from the ocean or firefighting, gets onto the hangar deck it can very quickly have a seriously destabilising effect due to the free surface effect. See the USS Franklin damage report section 9.

By way of comparison with earlier classes and the Forrestal/America/JFK and CVN here are the figures for the classes taken from Friedman:-

Essex - hull depth (to main/hangar deck) 54ft 8.25in. Depth to flight deck 81ft 7in
Midway - hull depth (to main/hangar deck) 57ft 6in. Depth to flight deck 84ft 0in.
Forrestal - hull depth 97ft 4in (note in this class the flight deck not the main/hangar deck was the strength deck so the hangar formed part of the hull)
Enterprise CVN-65 - hull depth 99ft 6 in
Nimitz - hull depth 100ft 6in

BUT:-
1. the draught of an Essex was about 23ft while that of a Midway was about 33ft. So the main/hangar deck of a Midway rode some 7ft closer to the waterline than an Essex or the best part of the depth of a whole deck.

2. a Midway had a hangar height of 17ft 6in. In later classes that increased to 25ft and then 26ft 6in in the Nimitz. That accounts for over half of the increase in hull depth.

Hey EwenS,

I think you made a typo? The draft of the Essex was ~28' 0" at full load, not 23' 0".

I only get a difference between the Essex and Midway (both as designed and ~built) of 3' 8" to 4' 1" to the Flight Deck, and 3' 2" to 3' 8" to the Hangar Deck.

Midway as built
Hull depth was 84' 0" to Flight Deck, and 57' 6" to Hangar Deck
32' 2" draft at 55,450 tons design displacement
34' 6" draft at 60,100 tons design full load displacement
so 51' 10" to 49' 6" freeboard to Flight Deck
and 25' 3" to 23' 0" freeboard to Hangar Deck

Essex class as built
Hull depth was 81' 7" to Flight Deck, and 54' 8" to Hangar Deck
26' 3" draft at 33,400 tons design displacement
28' 0" draft at 36,380 tons design full load displacement
so 55' 4" to 53' 7" freeboard to Flight Deck
and 28' 5" to 26' 8" freeboard to Hangar Deck

I stand corrected re my statement "Crew accommodations, as built, were considered superior to those of the Essex class". I had not run across the habitability issues mentioned by Friedman. I am wondering if what I was remembering was from after the SCB rebuilds?

So, how about we just focus on making the Skua smaller, lighter and more streamlined?

Admiral Beez said:

So, how about we just focus on making the Skua smaller, lighter and more streamlined?

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Why?
It was never going to be an effective fighter if it stayed with two seats.
It was the size and weight of a Dauntless. except it already had folding wings.

The problem wasn't the plane itself. It was the use of the plane.
Accept that two seat aircraft with a 900hp radial engine was never going to be a decent fighter and move on.
It could be decent strike aircraft and it could be decent scout/recon plane.

part of the problem with the size is that you need a certain size wing to get into air with desired bomb and fuel load if you use the Perseus (or Mercury) engine.
You also need a certain size wing to the the desired landing speed. Not sure how you make the plane much lighter. You are already using an engine of about 1000lbs. Unless you give up dive bombing you can't make the structure much lighter. And so on. Most planes were built to do certain jobs and the designers had a number of factors to consider. The best designs got the compromise right. Try for too much speed and you may have too high a take-off and landing speed. Or use too big an engine and you need more fuel for the range desired.
Sometimes the customer has to compromise. Maybe you can accept less range. landing 10% faster may mean a lot more wrecked airplanes.

Shortround6 said:

Why?

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Why? To make it a better dive bomber, and forget the fighter spec.

Admiral Beez said:

Why? To make it a better dive bomber, and forget the fighter spec.

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Did you have a problem with post #8454 in the Humpty Dumpty thread too?

Admiral Beez said:

Why? To make it a better dive bomber, and forget the fighter spec.

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OK, what do you want it to actually do?

My own opinion would be to mount a Pegasus engine (around 100lbs?) in the Skua to handle a bigger bomb load (improved bomber) and to handle increased weight of protection (armor and fuel tank protection). I have pointed out, several times, that the weight of four .303 guns and ammo isn't going to make much difference. Leave them in for strafing/flak suppression or take them out. Taking the guns out is only worth about 12 sq ft of wing area so you aren't going to change the size of the plane much at all.
There isn't much of anything else you can take out that is only a fighter part of the specification. Dive bombers need pretty much the same strength as a fighter for structure.
The Dive bomber needs at least as good a radio as the fighter, probably better.

The only thing you might want is more fuel for more range.

You already have a limited bomb capacity so you can't go any smaller.

More streamline you might be able to do but unless you change the engine the Perseus isn't going go very fast no matter what you do.
An extra 10-20mph isn't going to make much difference to survival.

AFAIK the only item of the Skua's fighter role was the guns and sight. It was a strike/dive bomber that could stray far away from the carrier in night and day and still find it again with the TAG in the rear seat with his token VGO. The prey was expected to be long range reconnaissance and bombers against whom it could bring to bear the same 4 guns as the Gladiator. The fighter role was incidental. More power would allow a larger bomb load/fuel load. What it would do for the fighter role would, again, be incidental. At the time of design the production available power units could not both make a fighter with useful performance versus a peer and carry a useful bomb load off a deck. Later power units could do so. At the time you could either go for a defensive fighter or an offensive strike aeroplane. Hence the Nimrod and the Osprey using the same engine for each role not a single unified design trying to do both. The Royal Navy went for the offensive choice. At that time it was looking at active service in the Atlantic with the Mediterranean being the province of the French navy. Hence it was not expecting to meet pure fighters. The US Navy was concerned more about the Pacific where they expected to meet a peer Japanese fleet so would meet peer fighters so needed their own fighters. No one expected the Luftwaffe to be operating out of Norway and the Biscay coast let alone across the Mediterranean together with the Italians. What their Lordships sought for fighters was fleet self defence against long range bombing and torpedo attacks so the short range Hurricane and Spitfire were their aim but were trumped by RAF home defence priorities so had to make do with the interim Sea Gladiator. In many ways the Fulmar was a better Skua.

To make a better fighter Skua is simply not possible. A better Skua, maybe. For a better fighter you want an entirely different airframe. Ideally not made by Blackburn……. Until Norway falls there was no telling argument for a wide ranging pure naval fighter for the Royal Navy. Certainly there were arguments for them, but not conclusive ones until it was certain that the Royal Navy would have to operate in seas subject to land based fighter opposition.

yulzari said:

To make a better fighter Skua is simply not possible.

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It is a shame that for its first all metal, monoplane, retractable and wide-track undercarriage, folding wing carrier aircraft the Air Ministry decided to pursue a dive bomber. Had they used these same resources and the above design elements to pursue a single seat fighter for service in 1938 they might have had a something quite impressive. Yes, we'll need to sort out a means for a single man to run the homing beacon receiver. The Swordfish and later Albacore can dive bomb, there's no need for the Skua.

yulzari said:

Until Norway falls there was no telling argument for a wide ranging pure naval fighter for the Royal Navy.

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Until the Skua the Royal Navy always had a single seat fighter (Pup, Camel, Nightjar, Flycatcher, Nimrod, Sea Gladiator). And yes with the exception of the Flycatcher they were all adaptations of RAF designs rather than pure naval fighters, but the RN's carriers always fielded single seat fighters that were to some degree competitive with their land based counterparts, until the Skua and then Fulmar/Firefly.

Admiral Beez said:

It is a shame that for its first all metal, monoplane, retractable and wide-track undercarriage, folding wing carrier aircraft the Air Ministry decided to pursue a dive bomber. Had they used these same resources and the above design elements to pursue a single seat fighter for service in 1938 they might have had a something quite impressive. Yes, we'll need to sort out a means for a single man to run the homing beacon receiver. The Swordfish and later Albacore can dive bomb, there's no need for the Skua.

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For 1938 service you need an engine, the Merlin III barely qualifies. A lot of 1938 production was the Merlin II that pretty much the same except for the prop shaft.
to sort out the homing receiver may require different radio gear. What was available in 1942 may not have been available in 1940 let alone in 1938, or it may have been. Right know we don't know.

There was a fair amount of debate on dive bombing. It to was changing/evolving. In 1937-38 you are doing daylight dive bombing (and for quite a bit after) because you don't have radar or good altimeters. The AA guns on ships were constantly evolving, sometimes slowly but things were changing. A plane like the Skua could approach quicker than a biplane. It could dive faster than a biplane (but not too quickly so as to maintain accuracy) and it could exit the target area quicker than a biplane. It could spend much less time in range of the AA guns.
You could use Biplanes to dive bomb, and here there were several different types of biplanes
US biplane dive bomber of 1937

There was a fixed landing gear Vought that could do 180mph at sea level and 200mph at higher altitudes.
The Swordfish could drop bombs while diving (and pull out) but it is not quite the same thing.

The RAF was all over the place with dive bombing.
Once the US went to monoplanes they used dive brakes to control the speed of the plane in the dive. For best accuracy you want the steepest dive you can manage and you need a certain number of seconds on a steady course (or minor corrections) and nearly a steady speed to aim the bomb. The dive brakes on the monoplane also limited the dive speed so that the bomb could be dropped at a lower attitude and still allow the pilot to pull out without hitting the ground or blacking out for so long that control of the aircraft was lost. Many dive bomber pilots did black out momentarily while pulling out.
The Fairey Battle was said to be strong enough to dive bomb. That is not quite the same thing. No dive Brakes and the propeller wasn't really suited for dive bombing. The Henley had no dive brakes and aside from the prototype had the wrong propeller but by that time they were target tugs. Dive bombing using Swordfish and Albacores was done, but it says a lot more about the crews than the men who procured the aircraft.
Please note the Germans were trying to fit dive brakes on many of their "dive bombers", they often didn't work but at least they realized they should have them.

Admiral Beez said:

Until the Skua the Royal Navy always had a single seat fighter, yes with the exception of the Flycatcher they were all adaptations of RAF designs rather than pure naval fighters, but the RN's carriers always fielded single seat fighters that were competitive with their land based counterparts, until the Skua and then Fulmar/Firefly.

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In the early 30s the British biplanes fell behind the land based counter parts. The Nimrod needs to be compared to the French D 510 or the Boing P-26 if you are comparing to land planes. perhaps the Nimrod was a match for the He 51 and Arado 65. The P-26 would have been hopeless as a carrier fighter.

Shortround6 said:

In the early 30s the British biplanes fell behind the land based counter parts. The Nimrod needs to be compared to the French D 510 or the Boing P-26 if you are comparing to land planes. perhaps the Nimrod was a match for the He 51 and Arado 65.

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Agreed. And it's to the Nimrod's successor where the resources for the FAA's first all metal, monoplane, retractable undercarriage, folding wing aircraft should have been focused. We can still use the Skua's Perseus engine, and start with the Mercury until the former is ready.

When it comes to dive bombing, you need to be clear about two things:-

1. exactly what do you mean by "dive" bombing? The term is usually restricted to aircraft that can dive at angles of 50+ degrees, not necessarily the full 90 degrees normally thought of. Japanese Val tactics normally used a 50-55 degree (it could be 45-70 degrees) dive with bomb release at 2,600ft (or as low as 1,900ft). For the USN SBD squadrons it was usually 50-70 degrees with bomb release at 1,900-2,500 ft, pulling out by 1,500ft.

2. what is your purpose? In the late 1920s and 1930s the main purpose for both the RN and the USN isn't to sink ships, let alone battleships. It is to tear up the enemy's carrier decks (to "mission kill" them in today's parlance) and to wipe out the AA gun crews on escorting ships to, in the case of the RN at least, allow the torpedo bombers to do their stuff. If lighter shps sink then so much the better, but sinking them is not the primary purpose.

So bombs up to 500lb are perfectly adequate for that purpose. It is the USN that begins to want 1,000lb weapons in its 1933 design requests that entered service from Dec 1937 in aircraft such as the SBC-4 and the Vought SB2U Vindicator. I've still to dig out a reason for that. In fact with that being the purpose are you better off with multiple 500lb hits or a single large 1,000lb hit? Once carriers gain armoured flight decks of course the game changes.

And how many carriers were sunk in WW2 by dive bombing alone? None. Numbers were sufficiently damaged that they had to withdraw for repairs or be scuttled. But it was generally torpedoes that let enough water into their hulls to finally put them underwater.

Dive bombing isn't easy, even against stationary targets. During Operation Bronte in 1948 the FAA was testing 1,000lb and 2,000lb armour piercing bombs against the Nelson anchored in the Firth of Forth. To penetrate her 6" deck armour it was calculated that the 2,000lb had to be dropped from at least 4,000ft. After missing with 39 bombs from 8,000ft the bombing height was reduced to 6,500ft before a hit was obtained with bomb number 42 from an actual dropping height of 5,900ft.

When the FAA bombed the Tirpitz in 1944 using, amongst other weapons, 1,600lb US made AP bombs, which it was estimated needed to be dropped from 2,000+ft. Hits with these weapons were very few (and not every aircraft was carrying one) and only one penetrated her main armoured deck and then didn't explode. One of the criticisms levelled at the pilots was that they were bombing from too low an altitude for the bombs to have enough penetrating power.

Admiral Beez said:

Agreed. And it's to the Nimrod's successor where the resources for the FAA's first all metal, monoplane, retractable undercarriage, folding wing aircraft should have been focused. We can still use the Skua's Perseus engine, and start with the Mercury until the former is ready.

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And that ignores the basic problem of how does the fighter of the 1930s, however good you make it, find its target independently when there is minimal / no direction from the warships below? And with increasing speeds of attacking aircraft, warning times got less regardless of how fast the fighter was.

That was the issue that drove the decisions that the RN made in the 1930s about reliance on ship's gunfire and armoured flight decks to protect its strike aircraft.

And the issue wasn't unique to the RN. The same converstion went on in the USN. There were even those in the USN that doubted that carrier fighters had a future. It is summed up neatly in this quaote from Friedman "Fighters over the Fleet".

" In Admiral 1934 Reeves (sic) himself wrote that he saw little point in continuing fighter development merely 'to keep up with the Joneses'. This was hardly a denial of the value of carrier air power, but rather an acceptance that the carriers were strong offensively but weak defensively."

Ultimately the USN chose to pursue a new fighter in their 1935 competition that led firstly to the Brewster F2A Buffalo that entered service in the second half of 1939, to be followed by the Grumman F4F a year later.

EwenS said:

When it comes to dive bombing, you need to be clear about two things:-

1. exactly what do you mean by "dive" bombing? The term is usually restricted to aircraft that can dive at angles of 50+ degrees, not necessarily the full 90 degrees normally thought of. Japanese Val tactics normally used a 50-55 degree (it could be 45-70 degrees) dive with bomb release at 2,600ft (or as low as 1,900ft). For the USN SBD squadrons it was usually 50-70 degrees with bomb release at 1,900-2,500 ft, pulling out by 1,500ft.

2. what is your purpose? In the late 1920s and 1930s the main purpose for both the RN and the USN isn't to sink ships, let alone battleships. It is to tear up the enemy's carrier decks (to "mission kill" them in today's parlance) and to wipe out the AA gun crews on escorting ships to, in the case of the RN at least, allow the torpedo bombers to do their stuff. If lighter shps sink then so much the better, but sinking them is not the primary purpose.

So bombs up to 500lb are perfectly adequate for that purpose. It is the USN that begins to want 1,000lb weapons in its 1933 design requests that entered service from Dec 1937 in aircraft such as the SBC-4 and the Vought SB2U Vindicator. I've still to dig out a reason for that. In fact with that being the purpose are you better off with multiple 500lb hits or a single large 1,000lb hit? Once carriers gain armoured flight decks of course the game changes.

And how many carriers were sunk in WW2 by dive bombing alone? None. Numbers were sufficiently damaged that they had to withdraw for repairs or be scuttled. But it was generally torpedoes that let enough water into their hulls to finally put them underwater.

Dive bombing isn't easy, even against stationary targets. During Operation Bronte in 1948 the FAA was testing 1,000lb and 2,000lb armour piercing bombs against the Nelson anchored in the Firth of Forth. To penetrate her 6" deck armour it was calculated that the 2,000lb had to be dropped from at least 4,000ft. After missing with 39 bombs from 8,000ft the bombing height was reduced to 6,500ft before a hit was obtained with bomb number 42 from an actual dropping height of 5,900ft.

When the FAA bombed the Tirpitz in 1944 using, amongst other weapons, 1,600lb US made AP bombs, which it was estimated needed to be dropped from 2,000+ft. Hits with these weapons were very few (and not every aircraft was carrying one) and only one penetrated her main armoured deck and then didn't explode. One of the criticisms levelled at the pilots was that they were bombing from too low an altitude for the bombs to have enough penetrating power.

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I may have posted this before. Regardless the USN was unhappy with their AP bombs. This is from the USN BuOrd history:


I have also attached the USN Study "Striking Power of Airborne Weapons". It is interesting to note that they don't even consider 500 lb bombs in their analysis of damage to any vessel larger than a destroyer.

Another point of interest is that the distance of what is considered a near miss can vary considerably with bomb size

Blast radius is another factor



What is more puzzling to me is why the Japanese often used SAP bombs. They are not capable of penetrating the main armored deck of an aircraft carrier and theie much smalleer explosive charge reduces their effectiveness particularly in the case of a near miss.

EwenS said:

And that ignores the basic problem of how does the fighter of the 1930s, however good you make it, find its target independently when there is minimal / no direction from the warships below?

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The same way the RN's fighters before the Skua, and those of the USN, IJNAS and Aéronavale did before the introduction of radar, Mark I eyeball with limited (if any) radio comm back to the mothership for reinforcements.