Why the Skua Only Carried a 500lb Bomb

[SaparotRob]

Of course, your mileage may vary.

 

[RCAFson]

Eric Brown discusses the Skua:


View: https://www.youtube.com/watch?v=X1bB4EhKVOo

 

[marathag]

Ouch.
Too bad FAA didn't have SBDs, that was without such bad habits, and was maneuverable

He could have done to the ME-109s what Swede Vejtasa did in his Dauntless against Zeros

 

[planespotting]

(This has been hastily completed after accidentally posting a half-written version, so I may have missed some obvious things?)

I like your moxie!

*confused Scotsman* Whit's a moxie?

As you can see, I'm not that well outfitted between the ears ...

Air-cooled?

From my point of view - no.

My view also.

But you would have had to steal them at gunpoint (.455 Webley?) from Bomber command as they were the engine of choice for the Hampden and Wellingtons of 1939/40 and part of 1941.

Versions of the Pegasus were also used for pretty much every British naval aircraft that isn't a Skua, too - the Swordfish, the Walrus, the Sunderland...

And is there something about radial design that makes it more useful to keep several similar Bristol radials in production, when there's a push for RR to ditch the Kestrel, Peregrine and Vulture to streamline production on the Merlin?

Me, I'd go for a 'big Spitfire' instead of 'small Fairey Battle' in order to make a 2-seat fighter for the FAA; also the engine must be the Merlin XX, not the Merlin VIII. Sorta Supermarine Type 305, but with backseater in place where turret was to go, and with fuel tank between the crew members. Drop tank installation - mandatory.

(historically, the Type 305 was Supermarine's design from August of 1935 for the spec F9/35 from 20th May 1935; obviously, the engine will not be the Mk.X back then, but Mk.II if we're lucky)

Logical. Does the big airframe have advantages in terms of fuel space that outweigh its size? You now have me pondering the resemblance between the rear cockpit on the actual two-seat Spitfire and the navigator's canopy on a Wellesley...

If the Pegasus was in short supply, and Hampdens were sitting around less engines for that reason, then maybe the solution could have been to use Daggers instead? Especially if deHavillend could be consulted on cooling improvements. A ex dH engineer told me many years ago that they looked at the Napier cooling design and concluded that it needed to concentrate more on getting lower pressure exits than on high pressure entry and he thought that dH could have made it work fine and they had plenty of air cooling practical experience.

Would this apply to the Napier Sabre too?

There are the specifications for what performance is required, then comes testing to see what the actual results are. The data I posted is from "Performance Tables of British Service Aircraft", Air Publication 1746 dated August 1939 but covering until 1941 or so. No graphs, just figures. Includes US built types. Signed off by the Permanent Under-Secretary of State. Since the RAF was only giving one top speed they largely chose 15,000 feet. To determine how much better or worse the Skua did versus the requirements means digging out the details of RAF specification O.27/34.

Thanks - I suppose I'm suspicious of these things because of the sort of "if we'd actually worked up to full power at design load, we calculate that we'd have met the design speed" statement that was used for ships' sea trials slightly earlier in the century (a topic I know marginally more about, though only through reading people like Friedman)...

And high altitude was well above 10,000 feet by the time the Skua was around.

As I said, I was showing my rank amateurishness in my choice of phrasing - what I meant was, as a practical height for intercepting Heinkels, wasn't designing the Whirlwind for 15,000ft fairly high-end at the time...?

Engines tend to stay in production while they have customers, in Q2/1939 apart from a few Taurus and Hercules, Bristol engine output was roughly 1 Perseus to 2 Pegasus to 4 Mercury.

Interesting - any idea whether the Mercury was in production for the Lysander at this point, or just the Blenheim?

The Perseus seems to have had things expected of it in the mid-1930s, with expected economy and an improved cowling being cited when it was swapped onto the Short Empire flying-boat, but (at the risk of oversimplifying in a hasty edit) would it be wrong to say it ended up being something of a second-choice motor? The original slim-fuselage M.15/35 torpedo-bomber seems to be its only design application, and everyone agreed it wasn't good enough for the resulting wide-body Beaufort and Botha (but the Botha had to keep it anyway)...

263 squadron describes its 24 October 1943 attack on the Munsterland as a low level one, the weather that day was bad. Similar restrictions apply to the Whirlwind and the Battle, mostly related to the G forces in any pull out from a dive.

There are a lot of contradictory explanations for why the original attack was ordered at low level - I'd suspected it was a combination of using 500lb bombs (though I've never seen that specified) and wanting to avoid flak...

The dive-bombing attacks on Münsterland were the subsequent ones, at least according to the the Corduroy book, but as I'm hastily editing this up when I posted a draft by accident, I've not dug through anything else on that yet...

It has been a long time since I read the USSBS reports, the bomb accuracy and notes about duds etc. are in various reports, like the attacks on oil industry targets. Many of the reports are available online.

Thanks anyway - I'll see what I can find!

While a re-engining of the Skua may be technically possible, the question would be why you would want to in 1939 considering how aircraft roles for the FAA had developed between 1934 & 1939..

The short answer would be that it would have been an interim solution; it's a proper carrier airframe that's already tooled-up in production, catapult-strengthened, tailhook-equipped, designed to belly-land at sea, with a lot of fuel, and folding wings, and if you can get a better fighter out of it with a better engine, surely that's useful?

That said, the details of what they were wanting are appreciated, and I've not yet looked into the practicalities of the Albacore's dive-bombing capability (the Barracuda illustrates the question I'm trying to ask, though - yes, it's a heavier dive-bomber, but it's not ready until mid-1943, and the whole point of what I'm asking about is getting something in the timeframe of the Sea Gladiator or Fulmar)...

So it appears another reason for the orders for the Fulmar replacing the Skua in the fighter role was a lack of alternatives within the timescale required.

That's sort of the point I'm making - they're looking everywhere for a decent carrier fighter, except the existing airframe, which could stand a better engine and a less intrusive canopy - think of the downrating of the Miles Kestrel to the Miles Master, only in reverse...

Thanks for the info on the US alternatives, though!

What I have re: performance -

Skua L.2888 (8,450 lb) 6,500 ft.
Gills fully closed, rich mixture, 2750 rpm
228 mph

"The correction for position error has not been finally agreed and for this reason the speeds above are approximate only, but are considered to be accurate to within +/- 3 m.p.h."

25 Feb 1939, A. & A.E.E.

Finally, something that looks like it's based on an actual flight test! I'm guessing that the "position error" is to do with measuring its actual performance on the ground during trials...?

Eric Brown discusses the Skua:


View: https://www.youtube.com/watch?v=X1bB4EhKVOo

Thanks!!

View attachment 717103Ouch.

And that answers the question. Ouch indeed. The Skua simply isn't very manoeuvrable, and... would I be right to think that stall-speed wouldn't be ideal for deck-landing?

 

[RCAFson]

View attachment 717103Ouch.
Too bad FAA didn't have SBDs, that was without such bad habits, and was maneuverable

He could have done to the ME-109s what Swede Vejtasa did in his Dauntless against Zeros

And yet the less than 190 Skuas that entered squadron service shot down several dozen EA (mostly Luftwaffe TE bombers off Norway), and these kills were verified via Axis/Luftwaffe combat and loss records.

None of Swede Vejtasa's SBD-> Zero kill claims were verified via IJN records:

A minute after Sellstrom's furious attack, it was the turn of Scouting Five on anti–torpedo-plane patrol to feel the sting of Zuikaku fighters. Deployed loosely in pairs, the eight SBDs turned up between the two groups of Zuikaku torpedo planes, but in position to intercept neither. There was no way the SBDs, cruising at 1,500 feet, could overhaul faster-moving torpedo planes with altitude advantage. The kankō were past before the SBDs could react. Some of the VS-5 pilots never even saw them. Suddenly there was trouble. Birney Strong glanced up to behold the sickening sight of three Zeros peeling off into an overhead attack on his dispersed SBDs. They were the three fighters of Lieut. Tsukamoto's Zuikaku 14th Shōtai, surprised to find nine "Curtiss bombers" (as the Japanese called the Dauntlesses) flying in their area. Their amazement brief, they tore into Strong's division. On the first pass, Tsukamoto and his wingmen shot off the tail of Ens. Kendall C. Campbell's SBD, then blasted a second Dauntless from the sky. They kept the surviving SBDs too busy to join forces for their mutual defense. Joining in the fight were PO1c Kanō's three Zuikaku Zeros, and they went after Woodhull's four SBDs as well. For the next several minutes, the Zuikaku Zeros made life miserable or impossible for Scouting Five, eventually accounting for four SBDs, flown by Lieut. (jg) Earl V. Johnson, Ens. Samuel J. Underhill, Ens. Edward B. Kinzer, and Ens. Campbell. In return Scouting Five claimed four Zeros shot down, one to Lieut. (jg) Stanley W. Vejtasa (later a renowned ace with Flatley's Fighting Ten). The Japanese, however, lost no fighters in this combat. (Lundstrom, First Team Vol 1)

Eric Brown was not a fan of the SBD describing it as:
"woefully underpowered and painfully slow". The Skua had been largely withdrawn from service before the SBD-2 appeared


Also, to be fair he said this about the SBD stall:

If the performance of the Dauntless was "sedate", particu-
larly with external load, at least it had few vices. It was a
pleasant aircraft to fly and its controls were light and respon-
sive unless it was heavily laden, and its stail, which, power off,
ranged from about 68 knots (126 km/h) at 10,000 Ib (4 536
kg) to some 62 knots at about 8,500 lb (3 856 kg), was totally
innocuous. But it did have one bad habit and that was a
vicious g stall, particularly off a tight left-hand turn, reminis
cent of that of the Fw 190. It would snap inverted without
warning, the nose falling through the horizontal and a spin
ensuing if corrective action was not taken immediately, (Wings of the navy)

 

[tomo pauk]

Versions of the Pegasus were also used for pretty much every British naval aircraft that isn't a Skua, too - the Swordfish, the Walrus, the Sunderland...

And is there something about radial design that makes it more useful to keep several similar Bristol radials in production, when there's a push for RR to ditch the Kestrel, Peregrine and Vulture to streamline production on the Merlin?

Me, I'd advocate for Bristol just making one or two small radials by 1935-ish. Pegasus is a given; where the Pegasus cannot fit install Mercury; ditch Perseus and Taurus (bar as prototypes).

Logical. Does the big airframe have advantages in terms of fuel space that outweigh its size? You now have me pondering the resemblance between the rear cockpit on the actual two-seat Spitfire and the navigator's canopy on a Wellesley...

Big airframe will be more amenable for increased fuel load vs. size. Problem with big airframe is that bigger size means bigger drag, and bigger drag means a slower A/C, that will tend to use the fuel in a more prodigal fashion.
People wanting to have long range/long endurance fighters in ww2 will need to recall that droppable fuel tanks were in use already inn early 1930s, and act accordingly.

 

[SaparotRob]

Moxie means chutzpah.

 

[RCAFson]

And that answers the question. Ouch indeed. The Skua simply isn't very manoeuvrable, and... would I be right to think that stall-speed wouldn't be ideal for deck-landing?

The 72 knot stall speed was 'all up' LG and flaps raised. Stall speed was ~66 knots in landing condition with flaps and LG extended according to Wings of the Navy.

Flying to the Limit states:

The Skua stalled at about 75 mph IAS with the flaps and undercarriage up and at 69 mph IAS with the flaps and undercarriage down. If the speed was reduced in a glide in the clean configuration, the aircraft tended to self-stall if the pilot did not push the stick forward. There was very little stall warning, with no airframe buffet, but when the stall did occur, a wing would drop, followed by the nose. This tended to occur even if the control column was eased forward, but if the aircraft was mishandled by pulling the stick back, it became quite violent and a falling leaf developed. With the flaps and undercarriage down the aircraft's characteristics were very similar, but it was slightly more mild-mannered. Once the nose had dropped and speed had increased, control could quickly be regained.

 

[marathag]

And that answers the question. Ouch indeed. The Skua simply isn't very manoeuvrable, and... would I be right to think that stall-speed wouldn't be ideal for deck-landing?

yeah, the speed itself isn't bad, but sudden stall behavior you don't want.
Devastator had a 63 mph landing speed, B5N Kate had a 72 mph landing speed

SBD had a 57 knot landing speed with full flaps and low fuel, to 73 knots , if trying to land at max take-off weight.

Leaving flaps up, added 8-11 knots to landing speed
stall behavior seems to have been to drop the left wing, but no warnings on a spin after that.

 

[marathag]

People wanting to have long range/long endurance fighters in ww2 will need to recall that droppable fuel tanks were in use already inn early 1930s, and act accordingly.

Not like Curtiss was keeping that a secret or anything

 

[RCAFson]

View attachment 717136
View attachment 717137
Not like Curtiss was keeping that a secret or anything

Yeah, but neither the USN F2A or F4F had them in Dec 1941. The F4F-4 had to wait until after Midway to get DTs.

 

[Shortround6]

One account of the Skua says it got the Perseus after the two prototypes got Mercury's because all the Mercury's were being allocated to Blenheim's.
In fact there was a shadow factory built to make Mercury's which may explain the preponderance of Mercury engines compared to other 3.

I have no idea if there was any parts interchangeable between the engines (Taurus may have used a few nuts, bolts, washers) the Mercury and Pegasus used the same diameter cylinders. Don't know if the heads were the same or any of the valve gear. The Perseus also used the same diameter cylinders and the same stroke as the Mercury but with the sleeves holding the piston and rings nothing outside the crankcase would be the same and a lot of stuff inside would be different.

The big problem Bristol had in 1939-40 and later was sleeve production. They thought they had it solved in 1938-39 but they could not maintain quality in volume production and since the Hercules and Perseus used the same cylinders (or at least the same size) it turned out that for every 3 Perseus engines you could have built two Hercules (sort of, 27 cylinders vs 28 cylinders) .
This may (Guess by me) the reason that around 1/2 of the Lysanders built had Mercury engines. This includes 150 0f the Canadian production (after the first 75 got Perseus) ALL the Lysanders III, all the Lysanders IIIAs and the 100 TT.MK IIIA target tugs (only ones specially built and not converted.)

 

[Shortround6]

Yeah, but neither the USN F2A or F4F had them in Dec 1941. The F4F-4 had to wait until after Midway to get DTs.

Blame the USAAC bomber Mafia for the USN not having drop tanks
CONSPIRACY !!!!

Still a Curtiss but later than the two photos above.

 

[buffnut453]

View attachment 717103Ouch.
Too bad FAA didn't have SBDs, that was without such bad habits, and was maneuverable

He could have done to the ME-109s what Swede Vejtasa did in his Dauntless against Zeros

Got to love it when we need a time machine to enable the Brits to make a "smart" decision.

First flight of the SBD was 1 May 1940.

First air-to-air kill by a Skua was on 26 September 1939. On 10 April 1940, Skuas sank the Konigsberg. Skuas remained engaged in operations over Norway until mid-June 1940.

Please explain what use the SBD would have been for ANY of these actions...and exactly how many Me109s the blueprint SBD might have shot down.

 

[marathag]

Got to love it when we need a time machine to enable the Brits to make a "smart" decision.

First flight of the SBD was 1 May 1940.

First air-to-air kill by a Skua was on 26 September 1939. On 10 April 1940, Skuas sank the Konigsberg. Skuas remained engaged in operations over Norway until mid-June 1940.

Please explain what use the SBD would have been for ANY of these actions...and exactly how many Me109s the blueprint SBD might have shot down.

Northrop, and then Douglas after the buyout, had been trying to sell attack aircraft to fill that role since the early '30s, military version of the Gamma, gradually improved, until the SBD was reached

Gamma 2E

BT-1 first flight 1935

XBT-1 with R-1535 and XBT-2 with R-1820, both with retractable gear. The XBT-2 flew in 1938, and had designation changed to SBD in 1939.

If the Chinese and Spanish could buy the Gamma in 1937, so could the FAA, and keep up with the improved models.

 

[ThomasP]

Except that the Gamma through SBD did not have folding wings, which was a requirement for the new armoured carriers (Ark Royal through Indefatigable) in order to fit on their elevators and to store a large number in their hangars (plus I am not sure if it would have fit on all of the non armoured carrier's elevators). And as pointed out by Buffnut453, the possibly worthwhile development (the SBD) did not become available until after the Skua was already in service.

Do not misunderstand me, I do not think there would have been any particular problem designing folding wings for the SBD - s simple break-wing mechanism at the joint where the inner and outer wing sections should be doable. The maximum width would then be determined by the tail span at 17' 9". The height with the wings folded might be a problem on the carriers with low 14' hangar height, but the rest of the carriers should be able to stow them.

However, in real life the British carrier strategy was significantly different than the US or Japanese, hence why put the effort into a foreign built airframe that will deliver a 1000 lb bomb, but requires a different supply chain, does not have folding wings and will not fit on any of the planned armoured deck carriers (other than as deck park), and will take up more hangar space than the Swordfish, Skua, Fulmar, or Albacore on the carriers that actually can stow it in their hangars?

 

[RCAFson]

Northrop, and then Douglas after the buyout, had been trying to sell attack aircraft to fill that role since the early '30s, military version of the Gamma, gradually improved, until the SBD was reached
View attachment 717208Gamma 2E
View attachment 717209BT-1 first flight 1935
View attachment 717210 XBT-1 with R-1535 and XBT-2 with R-1820, both with retractable gear. The XBT-2 flew in 1938, and had designation changed to SBD in 1939.

If the Chinese and Spanish could buy the Gamma in 1937, so could the FAA, and keep up with the improved models.

Why would the FAA want a fixed (non folding) wing DB that could not be struck down into most FAA carrier hangars?

BTW, the BT1 had it's own nasty stall characteristics, and the aircraft was sent to NACA for advise. This is from the NACA report:

STALLING CHARACTERISTICS
(Reference table IV)

Models BT-1 and XBT-2

Because of piloting difficulties experienced by squadrons
operating from aircraft carriers with the low-wing model BT-1
airplane, it was necessary that the stalling characteristics of
the airplane in the carrier-landing condition be materially
improved. The most objectionable characteristic was reported
to be a sudden fall-off of the left wing accompanied by rapid
aileron control-force reversal termed aileron "kick" at the stall.
Immediate flight tests were conducted at the plant to investigate
the validity of these reports and to determine a means of possible
improvement. The condition reported was verified by company pilots
and several modifications were found which could be incorporated
in service and would considerably improve the stalling character-
istics...

 

[marathag]

Why would the FAA want a fixed (non folding) wing DB that could not be struck down into most FAA carrier hangars?

BTW, the BT1 had it's own nasty stall characteristics, and the aircraft was sent to NACA for advise. This is from the NACA report:

Just to do what the Japanese did, buy a couple, to see what other were doing.
UK was kind of ignoring what others were doing, and didn't help that the RAF was choosing for FAA
'That's good enough for you, old chap'

Douglas was always improving their product, and helped that they had gained that promising young man, Ed Heinemann as Chief Engineer in 1936, after the takeover of Northrop.

Blackburn, OTOH.....

 

[SaparotRob]

...and exactly how many Me109s the blueprint SBD might have shot down.

All of them?

 

[Shortround6]

hence why put the effort into a foreign built airframe that will deliver a 1000 lb bomb, but requires a different supply chain,

You need a supply change that could deliver a 1000lb bomb, which the RAF could not until well into 1940.

Maybe there was something wrong with the Skua, but they managed to put the 4 gun turret into it to make the Roc and they still claimed it could take a 250lb under each wing plus 4 practice bombs. Moving the bombs out to the wings helped accomadate the 70 Imp gal aux tank. The tare weight was just over 600lbs more than the Skua but they planed to use the same engine.

I don't know what was going on here. I don't know how much freedom Blackburn had or of the Air Ministry was telling them what engine/s to use. Perhaps Blackburn didn't object strongly enough. Most accounts claim with the Botha that Blackburn wanted a more powerful engine (which the Beaufort got) but Blackburn was told to use the Perseus and make do.

I don't know how much freedom Douglas and the other American makers got or if certain airframe makers got more leeway than others.

We do know that many of the British programs were taking longer than planed. Some of the American ones were running not smoothly either.
The Roc overlapped the Skua. But the first Roc flew over 1 1/2 years after the first Skua. They should have know what they were getting. They also should have known that a plane designed to 1939 specification wasn't going to show up in service until 1942. Skua was ordered in July 1936, well over six months Before the prototype flew. There was always a delay between aircraft being completed at the factory and being issued to units and then a further delay before the unit is declared operational. It took Blackburn from Oct 1938 though March of 1939 to deliver the first 51 production aircraft. Thinking you can wait for aircraft that were still on paper in 1939 seems disconnected from reality.
In 1939 The US was issuing the Specifications for the SB2C and the Avenger. While they didn't order an interim aircraft for a torpedo bomber they were ordering the SBD to replace the biplane Helldivers and the Vindicators while they waited for the SB2C.

But as I have said, ordering a dive bomber for the RN that would use a 1000lb means that the RN could expect there would be a 1000lb bomb, of any type, to use.
In retrospect, get team working on the 1000lb bomb/s.
Toss the turret over the side of the Roc.
Stick a Pegasus in the Roc, even a single speed supercharger version.
Convert the later Rocs to this new version and order another batch.
Keeping making Fulmars.