Why the Skua Only Carried a 500lb Bomb

[yulzari]

The issue with foreign made engines, especially those needing to be supplied and supported across a possibly contested ocean, for the Air Ministry (aka Their Airships) was security of supply as was shown by the US engines purchased for the Beaufort still remaining somewhere under the North Atlantic.

I do agree that the lengthened nose to correct the centre of gravity with the Perseus could allow a heavier engine to be mounted further back but Their Lordships answer was to additionally put a better airframe behind that. To whit the Fulmar.

The Perseus was reliable enough to be used in all sorts of aeroplanes, including ones operating long distances and over the sea. Even the much criticised Taurus saw out its service principally in operations at sea. The issue was not being able to push it further in development so power was reined in to retain reliability. Bristol put their efforts into the much more important Hercules. Would that they had listened to the Poles in 1938, but would be for another thread. If Fairey could put a Hercules into an Albacore it seems plausible that Blackburn could put a Taurus onto a Skua were the demand there.

 

[RCAFson]

Two things are for certain:
The Skua had perfect provision for a more powerful engine, R-1830 or even an R-1820. But the brits were determined to not mix their native airframes with US motors.
Even in the most dire of circumstances, the aeronautical 'socialism' held sway.
The Bristol Perseus was unreliable and a dead end for every aircraft it was motored with, so without more HP there could be no more development.
An American radial would of allowed for a larger bomb, the Skua is larger than generally thought.

Also, in lieu of going for a scout/dive bomber with maneuverability, the FAA never really bought into dive bombing. Of course Taranto had a lot to do with that, but that was never repeated, was it?
Dive bombers continued to be effective in the Pacific. The FAA moved away from the scout/dive bomber and went for torpedo bomber/with shallow dive capability (which means not a true vertical dive bomber, hence less accuracy). The Fulmar and Barracuda essentially took the FAA out of serious combined ops for the rest of the war. Bad strategic and doctrinal thinking. How lucky they were to get away with it.

The early war (pre-USA entry) engines were not always models of reliability either, as the FAA discovered with the Martlet and the RAF with the Buffalo. The USA did intensive engine development from 1939-42, spurred on by UK purchases and then Lendlease.

The Swordfish could and did use near vertical divebombing and they and the Albacore and Barracuda were designed to use a steep 'divebomber' attack profile, when possible when dropping torpedoes. The Albacore and Barracuda were designed expressly for vertical divebombing using wing mounted bombs. Using a centreline bomb the Barracuda was limited to ~75degs due to the lack of a bomb crutch.

The Skua was 'a scout divebomber' designed for use against IJN carriers, but there weren't any Axis carriers in the ETO and 500lb bombs were of limited value against Axis heavy cruisers and battleships.

 

[Shortround6]

The British were nibbling at the American engines if not taking a full bite. They were certainly buying American engines for American planes like the Hudson.

But we get into several things here.
It wasn't so much " aeronautical 'socialism' " as the old boys network but I guess that depends on definitions of "socialism" and/or maintaining a viable competitive industry for future contracts.
The Hudson contract was met with more than a strongly worded letter to the Times in British aviation circles.


As far as re-engining already built aircraft goes. This has been done but not often. Some P-40s (number varies widely in some accounts) had their Merlin's pulled out and replaced by Allisons. Since all the parts needed were in the supply chain it wasn't all that hard.
Small numbers of aircraft that used both R-1820s and R-1830s swapped engines but again, both installations had been done at factories so what needed to be done had already been worked out. French actually swapped engines in some of their Hawk 75s late in the war or post war for training.
This is a bit different than having a factory change engines during a production run. I am not sure about the story on the HP Herefords. Some of the contract was changed during construction. How many were changed after being being built and by who (the Factory or the RAF?) I don't know.

 

[Shortround6]

The Skua was 'a scout divebomber' designed for use against IJN carriers, but there weren't any Axis carriers in the ETO and 500lb bombs were of limited value against Axis heavy cruisers and battleships.

The thing is that nobodies 500AP or SAP bomb was good against Battleships. Not for actually going through the armored deck or turret tops.
And Cruisers are not battleships.
There were darn few cruisers that needed a 500SAP bomb for most of the 1930s.
The last may be with hindsight but good estimates could be made at the time for some ships.

Problem with the SAP bomb was that it was a one bomb for everything solution with it not being the best bomb for much of anything.
Maybe it training easier? Simplified magazine storage in small magazines?

 

[EwenS]

The thing is that nobodies 500AP or SAP bomb was good against Battleships. Not for actually going through the armored deck or turret tops.
And Cruisers are not battleships.
There were darn few cruisers that needed a 500SAP bomb for most of the 1930s.
The last may be with hindsight but good estimates could be made at the time for some ships.

Problem with the SAP bomb was that it was a one bomb for everything solution with it not being the best bomb for much of anything.
Maybe it training easier? Simplified magazine storage in small magazines?

Everyone seems hung up on the dive bomber being used to sink battleships. The point is though that the purpose of the dive bomber in the 1930s was:-

For the USN, to find the enemy fleet first and damage the enemy's carriers sufficiently to prevent their own carriers being put out of action first i.e. to remove the enemy's eyes first. There was an expectation that their own carriers would not necessarily survive that first encounter.

For the RN, again damaging an enemy's carriers but also assaulting the enemy fleet's supporting warships to reduce or destroy their A.A. firepower. That would then ease the passage of the torpedo bombers which would secure enough hits to slow the enemy fleet down for the big guns to do their work.

Doing sufficient damage to an enemy carrier meant knocking holes in the flight deck and having weapons with enough penetrative power to punch through into the hangar spaces to ensure destruction of his aircraft or maybe even deeper.

While carriers of the 1930s might not have had armoured flight decks most had armoured decks of varying thicknesses further down in their structures protecting their vitals. In some cases that was a legacy of their origins as battleships or battlecruisers. But for most later ships it was still being built in. To get down to those levels required a bomb with a certain degree of penetrative power.

The navies of the 1930s were still living in a big gun centric world, expecting to fight the next Jutland or "decisive battle". Aircraft and their carriers were bit players to help that come about. The feeling was that you didn't need to sink an enemy carrier to put it out of action. Knocking holes in its flight deck was good enough to, in today's parlance, mission kill it.

As I've pointed out, the US move to larger 1,000lb HE bombs was to achieve a greater damaging effect on underwater hulls from near misses. It was Dec 1937 before the USN first got aircraft that could carry such weapons, starting with the Vought SB2U Vindicator followed by the Northrop BT-1 in 1938 and the Curtiss SBC-4 in March 1939.

 

[Shortround6]

You are quite right. Dive bombers against battleships in 1930s was not going to work regardless of the bomb. They (the bombs) are too small unless the BB in question was an un-modernized WW I relic. And even a 1000lb bomb has to be dropped from too high an altitude to get good accuracy.

There really weren't many enemy carriers in the 1930s.
By the end of 1937 the Japanese had 5 (barely, the Soryu completed by 2 days) when the Skua was supposed to go into service.
Hosho, no armor
Akagi, certainly, I have no details at the moment it was probably changed several times.
Akagi, the same
Ryujo, after the 1934-36 rebuild it was an 11,000-12,500ton ship? light plating over machinery and magazines, deck armor? how much was known to the British at the time?
Soryu, old book, correction welcome, 1in deck over machinery, 2.2in over the magazines. again what the British (or Americans) knew at the time?

The Hiryu was not completed until July 1939 and was not launched until Nov 1937 which makes her difficult to place in Skua planning.

If the British were planning on taking on the US in 1934-36 that changes the target selection
In 1936-37 any ships in the planning stages or just being laid down should have been the problem of the Skua's successor.

Granted some of the carrier flight decks were somewhat beefer than the upper decks of cruisers and battleships that didn't have 6-8,000lb planes landing on them at 60-70mph.

However there were a bunch of ships that could be targets, heavy cruisers, light cruisers, destroyers, fleet auxiliaries/depot ships, commerce raiders and so on than might not need (or even want) a SAP bomb.
It turns out with hindsight (or anybody that looked into the WW I actions and extrapolated) than battleships could also be mission killed (or severely degraded) by non penetrating HE bomb hits in the superstructure area. As the guns gained elevation and range the fire control equipment (directors and range finders) had to mounted higher above the water line for increased viewing range. These higher control stations could not be armored (or given more than splinter protection) due to top weight.

Kind of an extreme example and yes there were rangefinders down lower but this was no longer 1916 and fights in the haze of the North Sea.
at least 3 of the main turrets had huge rangefinders across the tops of the turrets for redundancy but the top one was 9-10 decks higher up and could see much further over the horizon if conditions permitted. There were separate range finders for the directors for the secondary guns and for the AA guns. Aside from setting fire to that skyscraper (or the aircraft hanger/facilities) there was a bunch of vulnerable stuff outside the armor that needed dockyard repair if damaged.
Combat experience (or hindsight) showed that a ship that lost it's fire control/radar early in the fight usually (always?) lost. This ship with 6 turrets is an extreme example but a dive bomber has a target around 100ft wide and close to 400ft long (guessing) where a hit is going to damage something.

Given the Skua's power I don't mind the 500lb weight limit. I mind the lack of choice to suit the limited bomb to the target type.

 

[SaparotRob]

Love the picture.

 

[Reluctant Poster]

Thank you for the attachment.
It certainly looks like the Navy didn't use the Army AP bombs unless it was in such small numbers that they never renamed them (dropped them in tests?) . I certainly don't know how long the Army had the bombs. No idea if the navy "borrowed" any after Pearl Harbor.

However there was a statement earlier about the Navy not liking AP bombs because of the small bursting charge gave very little results from a near miss ( I am rephrasing this) so it was pretty much hit or miss. Navy preferred the large burster of the GP bomb/s that would cause damage from near missed.

The 5% or under bursters in the Army AP bombs certainly go along with that.
Navy could have had their own test bombs that mirrored the Army ones and were never given a standard designation?

From reading Lundstrom there is no record of the USN using the US army's cobbled together AP bombs. It is interesting to compare the minimal level of effort the US army went to to convert artillery shells, ie simply adding a tail, with the major effort the Japanese went to in converting AP shells into bombs.

Japan 40 cm/45 (16.1") 3rd Year Type - NavWeaps

www.navweaps.com

 

[Reluctant Poster]

With the thick wing still not being recognised as a problem designers, such as Mitchell with the 4 engined Supermarine heavy bomber, took advantage of the RAF standard 250lb bomb to put them in the wings and save fuselage space. Bomb cells not only in the Battle but also the Stirling, Whitley and Halifax. In Supermarine's case the entire bomb load was in the wing bomb cells.

The Supermarine heavy bomber could carry 500 lb bombs in the wing cells. It also had a fuselage bomb bay which could accommodate up to 2000 lb bombs.

https://www.thewatchforum.co.uk/threads/losing-a-winner-the-supermarine-b-12-36-specification-type-317-heavy-bomber.148539/

 

[elbmc1969]

I do agree that the lengthened nose to correct the centre of gravity with the Perseus could allow a heavier engine to be mounted further back but Their Lordships answer was to additionally put a better airframe behind that. To whit the Fulmar.

Not a bomber. <shrug />

 

[RCAFson]

Not a bomber. <shrug />

The Fulmar II was designed to carry a 60IG slipper drop tank and the same attachment points could be used to carry a 500lb bomb. The Fulmar was tested, at Boscombe Down and cleared for the release of a 500lb bombs in dives of 60degs and over 300 knots. IIRC, the Fulmar served briefly as a strike aircraft.

 

[elbmc1969]

The Fulmar II was designed to carry a 60IG slipper drop tank and the same attachment points could be used to carry a 500lb bomb. The Fulmar was tested, at Boscombe Down and cleared for the release of a 500lb bombs in dives of 60degs and over 300 knots.

Sorry, I meant to type "dive bomber." A 60 degree dive and no dedicated dive brakes with the Fulmar's clean fuselage is not a dive bomber. The main problem is that the dispersion in distance in a 60 degree dive is shockingly long.

And while it may have assumed a strike role, it was not designed as a dive bomber and was not designated as such. Saying that it was a dive bomber is equivalent to saying that the F4U Corsair was a dive bomber. It may have been able to carry a 2000lb bomb and a pair of 1000lb bombs, and drop bombs in a 60 degree dive, but it was a fighter-bomber.

 

[Geoffrey Sinclair]

I am not sure about the story on the HP Herefords. Some of the contract was changed during construction. How many were changed after being being built and by who (the Factory or the RAF?) I don't know.

Hampden production, 502 by Handley Page September 1938 to August 1940, 770 by English Electric March 1940 to March 1942, the Ontario and Quebec groups in Canada built 160 Hampdens (80 each) November 1940 to May 1942. Total 1,432. Less 1 for Sweden and L7271 which became the Hereford prototype leaving 1,430 delivered for the RAF, but 75 retained in Canada.

Hereford production, 150 by Short and Harland August 1939 to September 1940. None delivered as Hampdens. Side notes: Hereford Mod 189 was fitting of self sealing fuel tanks (retrospectively) to be done in service by working parties from Short and Harland, minute dated 19 July 1940. Another minute dated 2 July? says 132 Hereford to have new skin panels and stringers by working parties from Short and Harland.

RAF Census February 1943, 1,430 Hampden and 150 Hereford delivered, of which 197 Hampden and 23 Hereford converted to Hampden Torpedo Bomber. As of June 1944 it was 251 Hampden and 23 Hereford converted to Hampden Torpedo bomber. As of February 1943 it meant only 10 Herefords remained, after the 23 conversions, 25 others to instructional airframes and 92 category E.

Several of the Hereford Serial Register pages are missing chunks, so the following cannot be comprehensive, marked converted to Hampden, L6011, L6018 to L6020, L6055, L6069, L6076, L6084, L6096, N9062, N9065, N9070, N9080, N9086, N9090, N9096, N9101, N9105, N9106, total 19 which suggests the RAF census total of 23 is credible. The candidates for the other 4 would be L6059, L6060, L6073, L6074, L6086 to L60901 which have missing serial register entries and N9082, N9083 which have blank serial register entries.

"The Hampden File" by Harry Moyle says 24 conversions, 13 L serials (but only gives 12 serials, missing L6084) and 11 N serials, adding L6049, L6085, L6089, L6090 and N9064 to the serial register list. Combining the two lists gives 24 conversions. It becomes 23 if L6085 is a typo for L6084 or vice versa. Of course the two references contradict each other over L6049, L6084/5 and N9064.

 

[Admiral Beez]

One of the Skua's weaknesses was that it could only carry a 500lb bomb, which was inadequate against battleships

The FAA didn't have a larger AP bomb than 500 lbs, so that's what they designed to. I'm sure with mods to the cradle and careful watch of the max takeoff weights that a 1,000 lb. AP bomb could have been fitted, if it existed. I'd also not assume a 500 lb. AP bomb dropped by a high angle DB is inadequate against battleships. Bismarck may be able to shirk off such a strike, but a Doria or Scharnhorst class? Maybe not.

provided less destructive power against (Japanese) carriers than the 1000lb bombs that were widely used by other dive bombers.

Considering the poor damage control and aircraft handling SOPs, plus lack of protection I imagine the Skua's 500 lb. AP bomb would have done just fine against Japanese carriers. At the Battle of Midway the SBD Dauntless divebombers crippled the IJN carriers with 500 lb. bombs.

One of my fantasy scenarios see four squadrons of Skuas recently retired from the fleet being transferred to Ceylon in Jan-Feb 1942, just in time to encounter Nagumo's Kido Butai and his dual neglect of CAP and situational awareness in March-April 1942. If those nine Blenheims could get through undetected to drop bombs close to Akagi, imagine forty or more Skuas diving from above.

 

[Shortround6]

The FAA didn't have a larger AP bomb than 500 lbs, so that's what they designed to. I'm sure with mods to the cradle and careful watch of the max takeoff weights that a 1,000 lb. AP bomb could have been fitted, if it existed.

It was a semi armor piercing bomb. SAP, not AP. At the time of design and issue to squadrons the RAF didn't have 1000lb bomb of any sort. It also did not have a 500lb AP bomb.
There is no mention of a 500lb HE or 500lb GP bomb being used by the Skua. Each bomb is going to be a bit different in size, both length and width/diameter.

Considering the poor damage control and aircraft handling SOPs, plus lack of protection I imagine the Skua's 500 lb. AP bomb would have done just fine against Japanese carriers. At the Battle of Midway the SBD Dauntless divebombers crippled the IJN carriers with 500 lb. bombs.

Been over this a bunch of times. British and US bombs were not the same. The US used different steel in the casings which could be thinner and allow more of the weight to be devoted to explosives. The US had no 500lb AP bombs at Midway.
They also had no 500lb SAP bombs.
They were using 500lb and 1000lb GP (general purpose) bombs.
US 500lb GP bomb held about 250lbs of HE.
British 500lb SAP held about 90lbs of HE.
British 500lb GP bomb held about 144lbs of HE.

The British did get 500lb MC (medium capacity) bombs later. After the Skuas were out of service.
The Japanese only had two carriers that came close to needing AP or SAP bombs to wreck the flight decks.

 

[Admiral Beez]

It was a semi armor piercing bomb. SAP, not AP.

Whoops, that's what I meant. What was the thinking behind the USN having no AP bombs for their DBs? Were the intended targets the unarmoured IJN flattops? What about the IJN's battleships, were those supposed to be the focus of torpedo bombers?

What did the Stukas that hit HMS Illustrious and Formidable have? Except for lucky lift or funnel hits those would be harder nuts to crack with GP bombs.

 

[Shortround6]

Were the intended targets the unarmoured IJN flattops?

I don't know.
Some people have said that the US Navy used GP bombs (and again, US GP bombs contained around 50% explosive by weight) to the wreck the top sides and because near misses into the water could cause both shock damage and leaks (sprung plates or cracks, depends on distance). A 1000lb GP bomb contained more HE than just about anybody's 18in aerial torpedo so that is not a threat to be taken lightly.
Destroyers had no armor and most cruisers were sketchy or piece work. Some Cruisers had armored magazines but not armored decks over the machinery spaces (or lightly armored).

The US figured that with the available aircraft of the 1930s they couldn't carry a bomb that would go through a new or reworked battleship deck so go for the degradation of the defenses and let the torpedo bombers get the actual kill.

US and Japanese may have had a different take on things than France, Italy and Germany. They were expecting to fight fairly close to home and getting damaged ships home may have been possible. German's certainly got some nearly sinking ships home in WW I. US and Japanese might have thousands of miles to cover to get a damaged ship home. Weeks rather than a couple of days.

For some reason people think that non AP bombs will either break up on impact or bounce off the ship (some bombs did) but that depends on what they hit, how they hit, if the fuses were set correctly and if the fuses function correctly.
And again, not all nations used the same steel for bomb casings.

 

[RCAFson]

The bombs that destroyed the IJN carriers at Midway, did so by igniting the fueled and armed aircraft in their hangars. The explosive filler of the bombs probably wasn't that much of a factor.

 

[Shortround6]

The bombs that destroyed the IJN carriers at Midway, did so by igniting the fueled and armed aircraft in their hangars. The explosive filler of the bombs probably wasn't that much of a factor.

Yes and no.

The bigger the blast the further away things are affected. Tanks ruptured or fuel lines ripped loose, etc.
Same with trying to set off bombs on bomb carriages or in bomb racks. Bombs close to the detonating bomb may detonate if they are close enough.

However the blast pressure goes up more with the square root of the weight of HE (?). that is double the weight does not get you twice the radius. In open air (air burst) the radius may be related to the cube root. In a hanger while some of the force goes into the floor/deck and some the roof/upper deck a lot more will get channeled fore and aft.

The end result may have been the same, it may have taken longer to get there. Or perhaps the Japanese may have been able to deal with the damage/fires from a single 90lb detonation. Or maybe not.

Everybody went for bigger bombs with much more HE as the war went on.

 

[planespotting]

Apologies for tagging a belated tangent onto an interesting discussion, but one thing that probably needs to be ascertained is what the performance of the Skua actually was.

The quoted 225 mph looks suspiciously rounded, and I'm not sure how to establish whether this is a design specification, a figure obtained with the Mercury XII engine on the prototype (830hp on takeoff, 890hp at 6,000ft, 51.5" diameter, and a weight I can't find stated, but presumably approximately 1000lbs) or a service speed with the theoretically draggier and less powerful Perseus XII (830hp on takeoff, 750hp at 6,500ft, 55.3" diameter, 1025lbs).

This 225 mph figure is often quoted as the speed at 6,500ft, i.e. the optimised altitude of the Perseus XII, but this may be an extrapolation based on the assumption that that's the natural height to peg the figure to; in contrast, Peter Caygill's Flying To The Limit, presumably using RAE dociments, says 225 mph is actually a sea-level figure, which looks very like a design specification, but on the other hand, should perhaps improve with altitude. The Roc, with the Perseus XII and a draggy turret, is quoted in the same source at 223 mph at 10,000 feet - would the Skua be expected to do a bit better?

Moreover, as these number suggest, the supercharger on both motors was optimised for a relatively low altitude, so I'd imagine a motor optimised for high-level performance would get a slightly better top-line speed, simply because good power at high altitude translates to higher speed in the thinner, less draggy air.

The question is, what motor? There's definitely room for improvement, if both the engines the Skua was flown with were too light for the airframe, and had to be jettied out two and a half feet ahead of the firewall - does that indicate something about the design process? How much more can be got out of a single-row radial? Would one of the big twin-row radials in the 2,000lb weight class, powerful but half-a-ton heavier and correspondingly thirsty, be practical, or would a Merlin be a better alternative than any of them? The Bristol Taurus, a small twin-row, weighs not much over 1250lbs and gives around 1100hp, but it's optimised for 5,000ft and at closer to 45" diameter, would it be to small? Apparently Alvis had a licensed version of the Gnôme-Rhone Mistral Major with a 52" diameter and a weight of under 1200lbs which gave over 1,000hp on the bench and had a high-altitude supercharger, all tooled-up with nowhere to go because the Air Ministry couldn't think of a good use for it...

And quite apart from engines, there's something to be said for a better propeller - the Skua used a two-speed prop, where the blades could pivot between two settings, one for take-off power and the other either for most-economical cruise or fastest possible dash, I'm not sure which; I've seen it said that it could be manually set at angles between the two extremes, but I'm not sure if that's true, and the general view seems to be that automatic "constant-speed" units handled such variation better than the average pilot, giving both a quicker climb and faster acceleration from manoeuvres in a fight.

And what else could be improved? Is there something to be gained in swapping the back-seater, who only seems to be there for morse-code messages and conversation, for seatback armour and a sleeker cockpit canopy? Can we get something with more fighter-like performance that still dive-bombs? And if so, which fighter does it equate to? The Gladiator? Fulmar? Sea Hurricane?

Everyone should feel free to brutally demolish any nonsense in what I've written - I'm really just an observer from the ground, and may only be showing my ignorance...

But, set up like a row of coconuts, a few more random observations on topics that have been raised in this discussion:

* A 500lb SAP/GP is probably less than ideal in a naval role; but the limited weight can be compensated for by doing what the IJN's Vals did repeatedly, mob targets with a reasonably large number of planes - as to the effectiveness of the tactic against armoured capital ships, the obvious example is USS Nevada, caught by a half-dozen Val hits that would have foundered her if she'd been on the open sea and unable to beach herself; HMS Warspite was sent to the rear for almost year by a couple of 500lb hits from Bf 109s, albeit Graf Zeppelin's specially-trained CAG, the Luftwaffe having decided that they didn't need to bother with the boat... beyond that, there simply aren't many examples, as the IJN switched to useless skip-bombing A6Ms and no-one sent Skuas against Tirpitz... but on the other hand, while the effects of a near miss by a large blast-bomb, raised in the previous Skua thread, certainly look impressive, the punchline there is that no-one actually noticed...

* BuShips damage analysis may not be very reliable at any level more detailed than "big jagged hole in the hangar deck"; I've seen all kinds of things misidentified as hits on opposing capital ships by US Navy battleship main-guns, including a pair of 1,000lb bombs from SBDs (Jean Bart at Casablanca, 1942)...

* The one RAF aircraft that could and did dive-bomb was, of all things, the Westland Whirlwind, which dropped pairs of 250lb in an 80° dive (I think using the trim tabs to recover); why a twin-engined high-altitude interceptor was given this capability I do not know, except that it seems a very Petter thing to do. The problem with overspeeding mentioned in some sources was caused by an unsatisfactory two-pitch prop, which de Havilland solved on a wet wednesday in the Battle of Britain by clocking the blade angle round by about three degrees, but I don't think they ever got a constant-speed unit, which explains why they never met their design performance in the high-altitude interceptor role...

* Speaking of the advantages of large, thin-skinned blast-bombs, and random things that de Havilland did on their own initiative in 1940...

Seems badly assembled bombs would not drop straight or would lose their tails, some Germans actually asked the US investigators post war what experiments were the allies doing with tail less bombs, which gives an idea of how often it happened.

Is it possible that Luftwaffe officers were asking about the fact that Berlin had been reduced to rubble by two-ton drums of HE toted by unusually-shaped flying pianos?

But I get the sense that Pathfinder Force didn't even tell Bomber Command what they were doing, so it's understandable that the USAAF might be confused...
The version I've read is that their lack of aerodynamics actually made them more accurate, as they didn't tend to "fly" like the finned equivalent. Those with more knowledge than me might want to comment on the plausibility of this claim?