1936 to mid-42: fast 1-engined bombers instead of slow types?

[GrauGeist]

While the Pe-2 was a solid performer , the comparable Tu-2 had much better range.

 

[K5083]

"
Even though it's kinda big the Caproni Ca.335 looks like a pretty good candidate too. Apparently there was also a more powerful dive bomber version

Caproni Ca.355 - Wikipedia

en.wikipedia.org


"


Dear /Wild Bill. About those Capronis. One of your links was to the elegant 335, fast, rangy, lousy payload. The second link was to the 355, which is the one I called a slug. And it is, the RA decided to use Ju87 instead.
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[Wild_Bill_Kelso]

While the Pe-2 was a solid performer , the comparable Tu-2 had much better range.

Right, but the Tu-2 came a bit later and for whatever reason seems to have been fairly slow to produce. By the time the Soviets had a decent number of them available, jets were flying around.

It's a bit analogous to the A-20 / DB-7 I keep mentioning, because I think it's a good example of a fast bomber even though two engined. The original versions had a light payload and very short range.... and relatively poor protection. But it was fast. The US wasn't very interested in them, initially it was a French order that got the ball rolling. The British, in spite of reservations about range and payload, adopted the type and started using it especially in the Middle East. It proved useful. The US brought some to the Pacific, where it again, proved useful in spite of limitations.

Each iteration got tougher, better protected, and longer ranged. The A-20G was a completely different, and far more capable beast than the original DB-7, with almost double the range, payload, internal protection, and defensive armament. Toward the end of the war, Douglas made the A-26 Invader, which was very fast (though at the time, perhaps less so compared to the fastest fighters) and heavily armed, well protected, and fairly long ranged. Of course by that point there were jets...

Engines got better through the war, the designers got better at figuring out how to cram more fuel into the airframe without destabilizing it, they got better at the defensive guns.

An early war light bomber is going to be either limited in range or slow, pick your preference. It can have dive bombing capability but that will make it slower, too slow (until you get to the level of an Aichi B7, by which time you are in the jet age)

Bomb loads similarly will start out small, (how many early bombers had bomb bays which were too small or configured such that they couldn't carry even medium sized bombs?) but it turns out even a humble bomb load, delivered over and over by a fast and relatively difficult to hit bomber can be useful. And as time goes on, the designers will figure out how to make it carry a larger and larger payload.

No design is going to tick all the boxes. What you want for an early war military aircraft is one which is good at something, and can be improved substantially over time. Hard to predict the latter, and I also don't think everyone knew which features were going to be really important. I think it turned out that speed was one of the important features.

 

[Wild_Bill_Kelso]

Speaking of jets - early jets had very short range and flying time, and didn't typically carry large payloads...

 

[tomo pauk]

An early war light bomber is going to be either limited in range or slow, pick your preference. It can have dive bombing capability but that will make it slower, too slow (until you get to the level of an Aichi B7, by which time you are in the jet age)

Dive bombing requirement does not automatically mean the aircraft is slow.

 

[Wild_Bill_Kelso]

Dive bombing requirement does not automatically mean the aircraft is slow.

I think it automatically means it's slower, all other things being equal. However, clearly toward the end of the war they figured out how to make it work in at least some cases, as we see in B7A, D4Y and several others, mostly that either didn't really arrive in time or had serious flaws (lack of protection on the D4Y). It just makes everything harder.

I am a 'fan' of dive bombers, in the sense that I do think they were more accurate than other bomber types, at least until wire guided or radio guided missiles / glide bombs became available, and I think bombing accuracy was and is extremely important. Much more than bomb load. Wire and radio guided munitions also had some issues of course.

However, it was very, very hard to make a good dive bomber that was also fast. Many types designed to be dive bombers either couldn't quite make the cut (wings ended up taking a set or bending, or even falling off during dive pull-out), or they were good at bombing but quite slow (Stuka, D3A, SBD, Skua, Albacore I'm lookin at you), or the 'dive bombing requirement' kind of made the design impossible to get working (He 177 is the classic example) or severely delayed it. Because it's such a tricky needle to thread.

Or it worked, and they were pretty fast, but eventually due to stress on the airframe pulling out of dives they had to pull back to something like not quite proper (i.e. very high angle) dive bombing. This would be for example Ju 88 and Pe 2. Or, closest thing to a single engine dive bomber - the A-36, which I think was actually a little more important than is given credit, but which they retired after some mysterious wing collapsing incidents and the realization that many of them were 'taking a set' etc. after repeated strikes.

I think what ultimately ended dive bombers for land warfare was this issue of making them fast, combined with the fact that fighter bombers like P-40s or Corsairs or Typhoons or Fw-190s could do shallow angle dive bombing and hit targets a lot better / more often than medium to high altitude level bombers could, but still survive a strike. And rockets of course though that is debated somewhat. And FBs could then fight afterward, at least some of the time, and tended to be pretty good at surviving being attacked by fighters after they dropped their bombs. And they were usually fast so could get out of the AO quickly, another important feature. So as we know, fighter bombers kind of took over the niche from dive bombers.

I think dive bombers still retained a role in naval warfare, and for all it's many, many flaws the SB2C was a fairly fast dive bomber which seemed able to hit targets. It's biggest drawback as a naval aircraft, aside from all the horrible teething issues, was range. I think basically it needed to be about 5 feet longer but wouldn't have fit on the elevators on a CV.

But fighter bombers and mast-height bombing done by light and medium bombers like A-20s and B-25s proved somewhat surprisingly effective at sinking ships too. Probably in a CVs vs. CVs battle out to sea, out of range of land based aircraft, you still want the extra edge in accuracy that the dive bombers give you. Especially if your torpedoes aren't so great. Making proper torpedo bombers that can fly fast is also another huge challenge obviously.

 

[Shortround6]

Part of what ended dive bombing for land targets was better AA guns. Obviously this varied from air force to air force depending on the opposition and also varied a lot from year to year.

Navies hung on bit longer, but navy targets were usually higher value and worth more losses.

Fighter bombers took over because they were harder targets to hit by AA even though they weren't as accurate. But trading a tank or pill box or artillery piece for a dive bomber was often not a good trade.

 

[Wild_Bill_Kelso]

Part of what ended dive bombing for land targets was better AA guns. Obviously this varied from air force to air force depending on the opposition and also varied a lot from year to year.

Navies hung on bit longer, but navy targets were usually higher value and worth more losses.

Fighter bombers took over because they were harder targets to hit by AA even though they weren't as accurate. But trading a tank or pill box or artillery piece for a dive bomber was often not a good trade.

Right, and I think this comes down to speed, basically. Agility and size as well. Most dive bombers were big and slow.

The A-36, as one of our few examples of a fast dive bomber used in land warfare, was able to function in a very dangerous environment (Italy) and hit targets from tanks to bridges at a fairly consistent rate and had a useful role as a result. It was more accurate than regular fighter bombers, but capable of surviving fairly well even in low level strikes, with suitable tactics.

 

[tomo pauk]

I think what ultimately ended dive bombers for land warfare was this issue of making them fast, combined with the fact that fighter bombers like P-40s or Corsairs or Typhoons or Fw-190s could do shallow angle dive bombing and hit targets a lot better / more often than medium to high altitude level bombers could, but still survive a strike.

P-40s and Corsairs were used as dive-bombers, the Corsairs using the extended U/C as dive brakes.
P-47s were also used as dive bombers as-is, deemed successful by the USAAF. Steep angles, no dive brakes:

 

[Wild_Bill_Kelso]

P-40s and Corsairs were used as dive-bombers, the Corsairs using the extended U/C as dive brakes.
P-47s were also used as dive bombers as-is, deemed successful by the USAAF. Steep angles, no dive brakes:

View attachment 694823

Steep but not, from what I understand, dive-bomber steep. It's called 'shallow angle dive bombing'. More accurate but not the same as say, what a Stuka does.

 

[Wild_Bill_Kelso]

The claim of 100 yards CEP in that document is impressive though! I saw a Navy study a while back that showed the SBD had a significantly smaller CEP than Corsairs did, but they were still pretty good (and harder to kill)

 

[tomo pauk]

Steep but not, from what I understand, dive-bomber steep. It's called 'shallow angle dive bombing'. More accurate but not the same as say, what a Stuka does.

Where exactly is the angle of the dive specified on the posted page?

 

[nuuumannn]

The Battle kinda was intended to do that and it wasn't capable of it.

The Battle was capable of doing what it was designed to do, the designers nor the RAF simply forgot to tell the Germans that. The use of a single-engined day bomber harks back to pre-war policy and the Battle was designed as a replacement for biplane Hinds and so forth, but its days were numbered simply because by the age of high-speed all-metal monoplanes, the concept became flawed. Demonstrating this was the fact that Battles were shot down in large numbers. The danger of operating such tactics in heavily defended airspace also warranted a change of tactic. Following this, the ground attack aircraft, exemplified in the Hurricane IIc became an effective strike weapon. The RAF Desert Air Force under Coningham represented a shift in doctrine, eventually leading to CAS and tactical strike in the RAF's Tactical Air Force, again led by Coningham, which made much more sense than the pre-war day bomber concept. There simply was no place for that concept on a modern battlefield.

 

[Wild_Bill_Kelso]

Where exactly is the angle of the dive specified on the posted page?

I get it from memoirs of pilots and various detailed accounts of battles, mostly MTO, China and Pacific, with Hurricanes, P-40s and Corsairs. The angle they usually mentioned is about 45 degrees. Much steeper than that and they would have needed a bomb cradle to swing the bomb past the propeller arc, and the airspeed would get too high for pullout.

 

[tomo pauk]

I get it from memoirs of pilots and various detailed accounts of battles, mostly MTO, China and Pacific, with Hurricanes, P-40s and Corsairs.

Text is specific about P-47s, in ETO.
See here for 90 deg dive bombing by P-47:

 

[Wild_Bill_Kelso]

Text is specific about P-47s, in ETO.
See here for 90 deg dive bombing by P-47:

View attachment 694996

Wow, fascinating, I stand corrected. Sounds like they worked it out. Do you know the date of this memo?

 

[tomo pauk]

Wow, fascinating, I stand corrected. Sounds like they worked it out. Do you know the date of this memo?

1944? The part of the doc has no date IIRC.
Pages are grabbed from the '8th pt. 4' report found here.

 

[Macandy]

What ended dive bombing was -
The radar guided director that could accurately track aircraft with fast changing bearings in all three axis. A dive bomber was a very hard target for regular directors.
The VT shell.
Reliable stand off anti ships weapons.

 

[Wild_Bill_Kelso]

That's about what I'd expect.

I was looking for some interview excerpts mentioning detail in dive bombing but drew a blank, most of what I earmarked etc. was to do with air to air combat.

I found a couple of nice videos though.

This is a pretty typical (except in the highly successful outcome) account of a dive bombing mission with a P-40 in the MTO. Pilot was on his fourth mission.



RAF P-40s dive bombing Monte Casino (in this one you can kind of make out the dive angle)

 

[Wild_Bill_Kelso]

What ended dive bombing was -
The radar guided director that could accurately track aircraft with fast changing bearings in all three axis. A dive bomber was a very hard target for regular directors.
The VT shell.
Reliable stand off anti ships weapons.

And yet, dive bombers were used by US Navy to the end of the war.

The stand off anti-ship weapons could be very effective, but they seem to have found countermeasures against them that also worked.