Dive bomber accuracy in perspective.

[davebender]

Ju-87 with average pilot had a 25% chance to place 1,000kg bomb within 30 meters of target.

Ju-88 under test conditions (presumably expert pilot) could place 50% of bombs within 50 meter circle.

What accuracy could be expected from a Vietnam era Skyraider with 2,000 lb iron bomb?

What accuracy could be expected from a modern day A-10 with 2,000 lb iron bomb?

 

[Zipper730]

The CEP figures are usually based on putting 50% of the bombs within a given radius, so the Ju-87 figures don't really give much for CEP computation.

Regardless the Ju-88 had a CEP of 50m or 164'0.5"

No idea about the Skyraider or A-10

 

[BiffF15]

The CEP for the A-10 with iron bombs is probably pretty good due to the death dot (CCIP) or Constantly Computed Impact Point. It's like a red dot sight for aircraft. Dot on, push pickle button, target hit, period dot. As for the Spad, I would think it's a bit better than WW2 iron. The predominate reason is time between WW2 and Vietnam gave room for much improvement in academics, techniques, tactics and procedures. Heck, range rides in the OV-10 would have almost all the BDU-33s falling inside 150' (non-combat dropping understood). The more you drop, the better you get.

Cheers,
Biff

 

[Greyman]

AFDU testing Hurricane II - 250 lb bombs:

low level attacks - 50 feet altitude

• average error varied between 16.5 yards and 22.4 yards
• most accurate form of attack - but unsatisfactory against point targets in action due to 11-sec fuses and bomb ricochet

dive attacks - 3,000 feet down to 1,000 feet (1,500 feet release) & 4,000 feet down to 2,000 feet (2,500 feet release)

• average error was 27 yards and 24 yards respectively
• form of attack judged vulnerable to AA fire, 45 degrees found to be the best angle for attack

AFDU testing of Mustang III - 500 lb bombs:

60 degree adive attacks - 8,000 feet down to 2,600 feet (release at 4,700 feet)

• average MPI error of 27 yards
• distance between bomb impact points 5 to 112 yards, average 46 yards

 

[pinehilljoe]

Ju-87 with average pilot had a 25% chance to place 1,000kg bomb within 30 meters of target.

Ju-88 under test conditions (presumably expert pilot) could place 50% of bombs within 50 meter circle.

What accuracy could be expected from a Vietnam era Skyraider with 2,000 lb iron bomb?

What accuracy could be expected from a modern day A-10 with 2,000 lb iron bomb?

1 in 4 hitting within 30 meters, you can see why the RN lost so many ships around Dunkerque, and Crete.

 

[stona]

AFDU testing Hurricane II - 250 lb bombs:

low level attacks - 50 feet altitude

• average error varied between 16.5 yards and 22.4 yards
• most accurate form of attack - but unsatisfactory against point targets in action due to 11-sec fuses and bomb ricochet

dive attacks - 3,000 feet down to 1,000 feet (1,500 feet release) & 4,000 feet down to 2,000 feet (2,500 feet release)

• average error was 27 yards and 24 yards respectively
• form of attack judged vulnerable to AA fire, 45 degrees found to be the best angle for attack

AFDU testing of Mustang III - 500 lb bombs:

60 degree adive attacks - 8,000 feet down to 2,600 feet (release at 4,700 feet)

• average MPI error of 27 yards
• distance between bomb impact points 5 to 112 yards, average 46 yards

The figures for 'real' dive bombing in 1944/5, by Typhoons and Spitfires, were nowhere near as good as this.

Cheers

Steve

 

[pinehilljoe]

Consider Enterprises Air Group of VS-6 and VB-6, 30 SBDs got 8 hits on Kaga and Akagi, that is better than 1 in 4, similar to Stuka accuracy.

 

[stona]

ORS 2nd TAF examined the accuracy of Typhoon bombers on operations between October 1944 and April 1945. Nine 'pin-point' bombing targets were analysed by plotting both bomb distribution from aerial photographs and examination of the targets on the ground. The average radial error for these attacks was 158 yards with only 50% of bombs falling within 130 yards of the target. The chances of actually destroying such a target are consequently rather slim.
Similar results were found in other surveys. For example a survey of seventeen railway line targets, 320 bombs dropped, found the average line error to be 69 yards with only 50% of bombs falling within 50 yards, either side of the target.

The Typhoons and Spitfires involved in these surveys were obviously not purpose built dive bombers but fighter bombers which employed various dive bombing techniques and this may be reflected in their relative inaccuracy. Their pilots may well have been less well trained in the arts of dive bombing than those from a unit established with this specific role and .at least some of the targets may have been defended. On the other hand these poor results are for targets which were easily visible from the air, such as bridges, railway lines and road or rail crossings. Results for other targets, which might be small and camouflaged, such as gun positions, would inevitably be far worse.

Cheers

Steve

 

[BiffF15]

The figures for 'real' dive bombing in 1944/5, by Typhoons and Spitfires, were nowhere near as good as this.

Cheers

Steve

The differences probably lie somewhere between training and reality. To little of the former and AAA of the latter...

Cheers,
Biff

 

[davebender]

not purpose built dive bombers but fighter bombers
I suspect purpose built dive bombers have features such as a better bomb release mechanism and superior bomb sights. In addition to crew that are fully trained (hopefully!) in that type of mission. Many of them such as Ju-87D and A-10 also have significant armor for protection against ground fire. There are other features too such as stability while diving that improve weapon accuracy.

 

[parsifal]

true divebombing was deadly to the RN until they began to beef up with AA able to reach to the top of the typical dive envelope. Bombs had to be dropped from a certain height so that they achieved sufficient vertical velocity for armour penetration. Varied of course with target, but for Illustrious the typical heights at which the ordinance was dropped was around 3000', not high enough to ensure penetration of the main armoured hangar deck

The record of hit on the Illlustrious were, according to Norman Friedman's British Carrier Aviation, which I think should be a fairly definitive source.

On 10th January there were eight hits:
1. 500lb bomb on S2 pom-pom
2. 1000lb bomb through port forward end of flight deck, bursting above the water outside the ship
3. 1000lb bomb through the aft lift exploding above the lift platform
4. 1000lb bomb through the flight deck on the centreline, exploding above the hangar deck
5. 500lb bomb on the edge of the aft lift, exploding high in the well
6. 1000lb bomb through P1 pompom, hit edge of armour deck but did not explode, did cause fire
7. 1000lb bomb near miss starboard side aft
8. 500lb bomb down aft liftwell.

delivered by 43 Ju 87s, some of which were diverted to attack other ships (15 from memory, no results recorded in the first attack)

As Aa suites increase, Divebomber loss rates began to climb alarmingly. A divebomber is a vulnerable target both during its form up and also during the dive, most vulnerable to CAP during form up and approach, and most vulnerable to attack from Flak during actual dive. beef up either of these defences and the divebomber as a concept is toast.

 

[parsifal]

ORS 2nd TAF examined the accuracy of Typhoon bombers on operations between October 1944 and April 1945. Nine 'pin-point' bombing targets were analysed by plotting both bomb distribution from aerial photographs and examination of the targets on the ground. The average radial error for these attacks was 158 yards with only 50% of bombs falling within 130 yards of the target. The chances of actually destroying such a target are consequently rather slim.
Similar results were found in other surveys. For example a survey of seventeen railway line targets, 320 bombs dropped, found the average line error to be 69 yards with only 50% of bombs falling within 50 yards, either side of the target.

The Typhoons and Spitfires involved in these surveys were obviously not purpose built dive bombers but fighter bombers which employed various dive bombing techniques and this may be reflected in their relative inaccuracy. Their pilots may well have been less well trained in the arts of dive bombing than those from a unit established with this specific role and .at least some of the targets may have been defended. On the other hand these poor results are for targets which were easily visible from the air, such as bridges, railway lines and road or rail crossings. Results for other targets, which might be small and camouflaged, such as gun positions, would inevitably be far worse.

Cheers

Steve

Agree completely however, a bomb 250lb or larger dropped within 50yds of a train, or most other targets except an AFV was likely to destroy the target. Trains were usually attacked in squadron strength, to ensure a kill for the train. Such was the effect on german train movements that by 1944 a train movement in western Europe was a rare thing. The germans didn't restrain themselves like this because they were not afraid of allied airpower....

Rockets were notoriously inaccurate, with about the same lethality as a 5/38" naval shell. During the landings at Gela, in Sicil, it was noted that shells falling within the 50yds radius were usually enough to de-track the attacking tigers, or upend them. a 5/38 however lacked the actual strength to actually knock out a tiger.

For Normandy. the statistics for hard AFV targets being knocked out by rocket firing typhoons were negligible, however the soft support vehicles were generally cut to pieces, and many of the heers precious tanks were lost due to fuel shortages and breakdowns. Aircraft working with the ground forces were deadly, aircraft trying to do their own thing were basically useless. Given enough time, a broken down tank can be repaired, or refuelled.

 

[pinehilljoe]

true divebombing was deadly to the RN until they began to beef up with AA able to reach to the top of the typical dive envelope. Bombs had to be dropped from a certain height so that they achieved sufficient vertical velocity for armour penetration. Varied of course with target, but for Illustrious the typical heights at which the ordinance was dropped was around 3000', not high enough to ensure penetration of the main armoured hangar deck

The record of hit on the Illlustrious were, according to Norman Friedman's British Carrier Aviation, which I think should be a fairly definitive source.

On 10th January there were eight hits:
1. 500lb bomb on S2 pom-pom
2. 1000lb bomb through port forward end of flight deck, bursting above the water outside the ship
3. 1000lb bomb through the aft lift exploding above the lift platform
4. 1000lb bomb through the flight deck on the centreline, exploding above the hangar deck
5. 500lb bomb on the edge of the aft lift, exploding high in the well
6. 1000lb bomb through P1 pompom, hit edge of armour deck but did not explode, did cause fire
7. 1000lb bomb near miss starboard side aft
8. 500lb bomb down aft liftwell.

delivered by 43 Ju 87s, some of which were diverted to attack other ships (15 from memory, no results recorded in the first attack)

As Aa suites increase, Divebomber loss rates began to climb alarmingly. A divebomber is a vulnerable target both during its form up and also during the dive, most vulnerable to CAP during form up and approach, and most vulnerable to attack from Flak during actual dive. beef up either of these defences and the divebomber as a concept is toast.

Eight hits on a carrier size target by about 25 Stukas, that's what I would call deadly accurate.

 

[parsifal]

the attacks on illustrious was essentially a training exercise. the form up point was 10000', well above the CAP which was caught low and out of position. Diving singly or in pairs the Ju-87 would initially descend to 5000' stop briefly. 5000' is the equivalent of point blank range. but still well above effective range of the main LAA weapon available to the RN at that time (40mm pom poms). Peeling off individually from that intermediate, the stukas would then descend even lower to about 3000 feet where the ordinance was released. it was in the runs out of the target area that the late arriving Fulmars finally tucked in and shot a few up.

it doesn't get better than 10 January 1941 for the divebombers

 

[Shortround6]

Many of them such as Ju-87D and A-10 also have significant armor for protection against ground fire.

Depends on the ground fire.

British army AA in 1940 was 4 Bren guns on individual mounts on the back of small trucks per battalion. In 1941 the mounts were changed to twin mounts. Heavier guns were pretty much WW I 3in/20cwt guns that weren't much use against dive bombers. By 1944 a British division had 54 40mm Bofors guns and an assortment of 20m guns. Carrying protection against 20mm guns for a Ju 87 is dubious
and against 40mm guns is impossible.

Grouping the Ju-87 and the A-10 together is laughable. While both do the same sort of missions (sort of) the A-10 weighs empty about 3 times as much as JU-87D, around what a B-26 Marauder weighed, and loaded it weighs about what an early B-17 weighed. For power they are so far apart it is almost impossible to compare. An A-10 has more thrust than an F-100 Super Sabre and about 20% more power than a Canberra bomber. Between the engine power and metallurgy (titanium armor) they is no way that the protection of an A-10 and a Ju-87 are comparable.

 

[pbehn]

What a dive bomber can achieve depends on the target, a trawler/destroyer is much more difficult to hit than a carrier and not just because of its size it can also change direction much more quickly.

 

[stona]

What a dive bomber can achieve depends on the target, a trawler/destroyer is much more difficult to hit than a carrier and not just because of its size it can also change direction much more quickly.

This is correct, but it was not obvious at the beginning of the war. The Royal Navy's "Air Defence Instructions, 1939" forbade fast avoiding action against dive bombers. Many ships' commanding officers took a different view and the matter was referred to the director of the Naval Air Division in 1940. He conceded that avoiding action might cause a reduction in bombing accuracy because it would cause the pilot to adjust his aim, which was not regarded as easy, but in conclusion reinforced the official view that avoiding action should not be taken at the expense of throwing off the ship's AA fire.
Maneuverable ships, like destroyers, might be better able to 'dodge' bombs than others. It has been suggested that the destroyer Gurkha was lost to air attack in the Norwegian campaign because her Captain was a 'gunnery officer' who believed in the efficacy of AA fire and chose to keep a steady gun platform without weaving, thereby also presenting a steady target.
Later 'dodging' became the norm.
Alec Dennis was on board the destroyer Griffin as part of Force B off Crete when attacked (along with Greyhound, Gloucester and Fiji) by JU 87s. Twenty Ju 87s made the first attack comingdown in,
"groups of three, one after the other, dividing their attention among all four ships. It was a classic attack, technically interesting, physically terrifying and, actually, ineffectual."
Dennis described how all the bombs missed as they weaved about at full speed with the cruisers (Gloucester and Fiji) throwing up large amounts of flak.
Clearly evasive action did work. Fiji would later endure nearly 13 hours of air attack before finally being hit. She had run out of ammunition and was defiantly firing practice ammunition, solid shot, at the attacking aircraft!
The destroyer Kipling was attacked 83 times in one three hour period, but was not hit.
The light cruiser Naiad managed to dodge 36 near misses in one ten minute period before eventually being hit.
It was these stories, and many like them, that led Cunningham to write (in 'A Sailor's Odyssey'):
"The hasty conclusion that ships are impotent in the face of air attack should not be drawn from the Battle of Crete."
His colleagues in the USN would soon find reason to agree.

Cheers

Steve

 

[RCAFson]

Fairey Swordfish as divebomber:

The Swordfish was also capable of operating as a dive-bomber. During 1939, Swordfish onboard HMS Glorious participated in a series of dive-bombing trials, during which 439 practice bombs were dropped at dive angles of 60, 67 and 70 degrees, against the target ship HMS Centurion. Tests against a stationary target showed an average error of 49 yd (45 m) from a release height of 1,300 ft (400 m) and a dive angle of 70 degrees; tests against a manoeuvring target showed an average error of 44 yd (40 m) from a drop height of 1,800 ft (550 m) and a dive angle of 60 degrees.
Fairey Swordfish - Wikipedia​

 

[michaelmaltby]

Didn't Louis Mountbatten lose his destroyer Kelly off Crete to a dive bomb down the ship's funnel? Now that's a pickle in a barrel.

 

[stona]

Not quite.
On that day, having survived two earlier attacks, Kelly and Kashmir were attacked by Ju 87s. Kashmir was hit first. Kelly continued to carry out evasive manoeuvres, dodging some bombs, before being hit, in Mountbatten's words, "square on X gun-deck."
He lost control of the ship which started to list badly. He would later write

"I realised the bomb must have torn a gaping hole down near X magazine, as we had lost our stability and were rolling right over. I suddenly saw the water rise on our port side in a raging torrent of over 30 knots and thinking, 'Whatever happens I must stay with the ship as long as I can. I must be the last to leave her alive."

I'd say 'square on X gun deck' was still a pretty good effort, from a German point of view, even if not quite as dramatic as a bomb down the funnel.

I'm not sure what the fate of the fictional Torrin was in that awful film (In Which We Serve) in which Noel Coward plays a thinly disguised Mountbatten, but maybe the bomb down the funnel comes from there?

Cheers

Steve