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

[Wild_Bill_Kelso]

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

 

[K5083]

OK, we've been all round the houses but have we actually found or imagined a single-engined bomber which was not either a tactical aircraft or carrier-borne? Have we found an example of an air force specifying such an aircraft for bombing at a more strategic level after the Battle/Mary/Ann generation? I'd propose that the answer is no, and the reason is that you gain so much in terms of proper bomber capability by having more engines. It's not that it couldn't be done, but that it wasn't worth doing.

 

[K5083]

" Caproni Ca.335 looks like a pretty good candidate too."


Jeez Bill, that looks like an under-powered slug.

 

[tomo pauk]

OK, we've been all round the houses but have we actually found or imagined a single-engined bomber which was not either a tactical aircraft or carrier-borne? Have we found an example of an air force specifying such an aircraft for bombing at a more strategic level after the Battle/Mary/Ann generation?

Thread's title specifies that fast 1-engined bombers are produced instead the slow 1-engined bombers. That includes also the tactical bombers, like the Ju 87, Il-2, Su-2, Ba.65, A-24, PZL.23.

 

[GrauGeist]

" Caproni Ca.335 looks like a pretty good candidate too."


Jeez Bill, that looks like an under-powered slug.

It had fairly good performance reported during it's trials and with a top speed of 330mph, it would have been hard to catch in 1939/1940

 

[Wild_Bill_Kelso]

OK, we've been all round the houses but have we actually found or imagined a single-engined bomber which was not either a tactical aircraft or carrier-borne? Have we found an example of an air force specifying such an aircraft for bombing at a more strategic level after the Battle/Mary/Ann generation? I'd propose that the answer is no, and the reason is that you gain so much in terms of proper bomber capability by having more engines. It's not that it couldn't be done, but that it wasn't worth doing.

It's not a "What was" thread but rather a "What If" thread, which is a general concept people seem to sometimes have a real hard time grasping in here occasionally.

We know they didn't really do this, the question was (I believe) could it have been done. And I think the answer is, yes probably, based on some existing aircraft.

So to your specific question - yes we can imagine it. The closest thing to a reality by the time the war started was really a fighter-bomber or a dive bomber.

Why is Tactical aircraft a bad thing? I think yes most light bombers are of necessity going to be tactical aircraft. So what? Tactical aircraft were of vital importance in the war.

 

[Wild_Bill_Kelso]

" Caproni Ca.335 looks like a pretty good candidate too."


Jeez Bill, that looks like an under-powered slug.

A slug? Really? You got examples of a lot of bombers that are faster than that in 1939?

 

[Shortround6]

A slug? Really? You got examples of a lot of bombers that are faster than that in 1939?

Sort of.

the single-tailed prototype set a speed record over a 100 km (60 mi) circuit on 1 April 1937 by reaching 517.84 km/h (322 mph)
Another record was obtained on 10 April 1937 when it achieved 475 km/h (295 mph) over 1,000 km (620 mi).
This record speed was increased to 554 km/h (344 mph) when the modified prototype, using a double tail, was re-equipped with the definitive engines; the 746 kW (1,000 hp) Piaggio P.XI-RC40s.
This time it broke German records in a 100 km (60 mi) stage at an average speed of 554.4 km/h/344.5 mph (with 1,000 kg/2,200 lb load) on 5 December 1937.
9 December 1937, another world record was set when averaging 524 km/h (326 mph) over 1,000 km (621 mi) with a 1,000 kg (2,200 lb) load.

better known as the Breda B.88

often used as a decoy target to distract allied aircraft attacking airfields.

Prototypes and record setting did not always make for good warplanes.

 

[Wild_Bill_Kelso]

I am fully aware of the production and operational history of the Ba.88, as are most people familiar with the basics of WW2 Aviation history.

Of course it is possible to take a promising looking pre-war design and pile on necessary but heavy wartime gear and make it into a dud. Ba 88 however had some unique design problems and not much room to grow as an airframe, IMO. The same cannot necessarily be said for all pre-war designs.

IMO the biggest problem preventing wider use of fast single-engined bombers was that 1) engines weren't considered reliable enough and were only just starting to become powerful - with the most powerful only available in certain areas, thus the tendency to make twin or three engined light / fast bombers 2) A lot of interest for Tactical bombers was focused on dive bombing, which made everything much more complicated on the design level, and had a direct impact on speed in particular, and 3) I don't think the idea of aircraft with relatively high wing loading was widely accepted yet, and of course as we can see with the Ba-88, had it's own inherent perils.

If you made a promising prototype that can go 300+ mph with a 1,000 load, and handle well, it will still need to handle well after adding another 1,000 lbs so the design needs more room to grow in terms of the airframe being able to handle additional weight. i.e. it's not just a matter of more powerful engines becoming available when and if they do.

 

[Shortround6]

IMO the biggest problem preventing wider use of fast single-engined bombers was that 1) engines weren't considered reliable enough and were only just starting to become powerful - with the most powerful only available in certain areas, thus the tendency to make twin or three engined light / fast bombers

I am in agreement, mostly. By the late 30s the engines were fairly reliable, long lived was different. and in 1939 there was a large discrepancy in power between nations. The US had 1600hp available (just going into production) and the Italians had about 1000hp and everybody else was in-between. This is for engines that were type tested and at least in small scale production ( a dozen or 20 per month)

2) A lot of interest for Tactical bombers was focused on dive bombing, which made everything much more complicated on the design level, and had a direct impact on speed in particular,

Also true. A dive bomber needs a heavier structure than a level bombers.

3) I don't think the idea of aircraft with relatively high wing loading was widely accepted yet, and of course as we can see with the Ba-88, had it's own inherent perils.

Also true. High wing loading means high take-off speeds and high landing speeds which means longer airfields. If you want to use a bigger wing for short field performance you have to accept a bit lower speed. If you have one of the more powerful engines perhaps you can do the trade-off. If you are stuck with a lower power engine perhaps you can't.

The low powered aircraft also often has to decide between fuel (or range) vs bomb load. A big wing allows for greater load with the same engine. A fast, but short ranged bomber may not be able to reach the desired (or intended) targets making it a poor choice for the money spent. You can't always get everything you want and sometimes niche aircraft have to take 2nd place to more general purpose aircraft.

The Breda B. 88, in part, ran into trouble because the engines ran into a wall. They were licensed G-R 14Ks (for the most part) and France had moved on to the 14Ns to get over 1000hp, The Russians were following their own path with the G-R 14K license and went through the M-87 and M-88 engines and they never got them past 1100hp (?).
Without redesigning the whole aircraft The B. 88 was stuck, leave 33% of the bomb load behind? pull one or two of the 12.7mm guns? leave behind several hundred liters of fuel?
A combination?

 

[tomo pauk]

The Breda B. 88, in part, ran into trouble because the engines ran into a wall. They were licensed G-R 14Ks (for the most part)

Without redesigning the whole aircraft The B. 88 was stuck, leave 33% of the bomb load behind? pull one or two of the 12.7mm guns? leave behind several hundred liters of fuel?
A combination?

Other people were making a good, if not excellent use of 1000 HP engines, so we perhaps need to look at the airframe? Fuselage sported the welded steel tubes frame, around what the stressed 'skin' was wrapped. Other people either wrapped the steel tubes with fabric, or were not even thinking about the steel tubes' frame if the aircraft is of the stressed skin design.
Empty weight was at 4650 kg, that we can compare with for example the Ki-46-II (about same dimensions) weighting 3260 kg, or the Ki-45 at 4000 kg. Ki-46-III was at 3830 kg empty.
So yes, unless the aircraft is redesigned, seems like bombs indeed need to remain on the ground.

 

[tomo pauk]

The Russians were following their own path with the G-R 14K license and went through the M-87 and M-88 engines and they never got them past 1100hp (?).

There was a small series of the M-88F engines made, 1250 HP for take off.
The M-82 was a far superior engine, but we know that already.

 

[K5083]

There's nothing at all wrong with a tactical aircraft. Surface forces need support from the air and that's the way to do it. But what is the mission of our what-if bomber if it isn't tactical? Do we expect to invest in it to, for the RAF, fly to the Ruhr from UK bases and be anything more than a nuisance? The Battle kinda was intended to do that and it wasn't capable of it. The RAF went to two then four engines because that was a way to get a suitable tonnage delivered, using a force of thousands. To do it by night you need a navigator and a proper bombsight station. To do it by day you need speed as well. I don't say it can't be done, only that there's no point. And maybe I'm lacking imagination but I can't see any other nation's air arm having a mission for it either outside of tactical.

 

[Shortround6]

There's nothing at all wrong with a tactical aircraft. Surface forces need support from the air and that's the way to do it. But what is the mission of our what-if bomber if it isn't tactical? Do we expect to invest in it to, for the RAF, fly to the Ruhr from UK bases and be anything more than a nuisance? The Battle kinda was intended to do that and it wasn't capable of it. The RAF went to two then four engines because that was a way to get a suitable tonnage delivered, using a force of thousands. To do it by night you need a navigator and a proper bombsight station. To do it by day you need speed as well. I don't say it can't be done, only that there's no point. And maybe I'm lacking imagination but I can't see any other nation's air arm having a mission for it either outside of tactical.

You may be right. Britain was trying to up grade and do it both fast and cheap, they were also trying to skirt a possible international arms treaty that didn't happen. The result for Britain was contract for a lot of Battles and not a good way way out of the contract. Canceling the cintract means that you might have gone to war in 1938-39 with a lot more Hawler Harts still in service.

The Fairey P.4/34 and the Hawker Henley show what happened when the long range strategic part went away. Bombload was cut in 1/2 and range was reduced in an effort to get speed with the same engine. But then the doctrine flipped back the other way and the RAF hid the Henley as target tugs rather than support the army.
, You do have several types of tactical targets, the enemy on a hill right in front of your troops or the enemy artillery in a valley behind the hill or the enemy supply columns/routes 20- 100 miles behind the front lines (which should be in artillery range). RAF hid the Henleys and went back to insisting their job was to bomb the factories before the supplies (ammo, more guns etc) even made it to the rail lines let alone trucks or wagons trundling up to the rear of the front.

The Japanese bought quite a few single engine bombers, 704 Ki-30s from 1938 to 1941 and 854 Ki-32 from 1938 on. Saw a lot service in China and against the Chinese air defenses they did quite well. The Japanese also bought over 2500 Ki-51s for more tactical roles. However China and the rest of Asia and the islands were a vast area and the Japanese needed range to hit targets at a distance rather than moving the aircraft ever few days as the front lines moved.

Russia may have had missions?
Attacking Finland?
The Baltic states?
Attacking Poland?
Bulgaria and Rumania?
Russian missions changed in June of 1941.

 

[ThomasP]

I may be thinking about this the wrong way, but does the FAA's use of their Swordfish and Albacore Sqns operating from land in support of the various ground forces in NA and MTO count as tactical and/or maybe grand tactical? If so, then I think that would be an answer as to whether the single-engine fast bomber would fill a need within the British air doctrine of the time. Maybe?

 

[Shortround6]

I may be thinking about this the wrong way, but does the FAA's use of their Swordfish and Albacore Sqns operating from land in support of the various ground forces in NA and MTO count as tactical and/or maybe grand tactical?

Maybe...................But they sure aren't fast

Now why do we want speed?
Are the short range tactical planes escorted?
Do the short range tactical planes need speed to avoid enemy aircraft if unescorted or does speed help avoid ground fire?
How much warning does the enemy get for short range tactical?
It is grand tactical (supply routes?) how deep time wise, 30 minutes or 1 hour into enemy airspace. Escorted or unescorted? How big a speed difference is enough to give a decent change of survival ?

 

[Wild_Bill_Kelso]

A-20s / DB-7s were very short range when they first went into action. But they proved to be highly useful. Gradually they got longer legs but they were never more than medium range strike planes, yet they were in use to the end of the war IIRC.

The Pe-2 similarly had a fairly short range, especially when carrying a lot of bombs. And yet, it was considered one of the most important strike aircraft in the Soviet arsenal.

Ju-87s were also quite short range initially, but clearly they had quite a useful niche through the middle of the war, in fact it was crucial to the success of the German land armies. It eventually became obsolete - due to being so slow.

When you put bombs on them, the early fighter bombers like Hurricanes and P-40s had quite short range (especially the Hurricanes) but they were noted for their usefulness in the war effort.

The Tactical battlefields were found in every Theater, with the exception of NW Europe, in the early to mid war. NW Europe also became tactical after mid 1944 obviously.

The Japanese and their opponents were not exclusively flying long missions between islands. In fact some of the most crucial battles were fought on the larger landmasses and / or closer island chains such as in and around New Guinea in the early part of the Pacific War and all the shorter ranged light bombers and fighter-bombers proved useful, some of them critical.

The Med, from Western Desert through Italy, had a lot of Tactical bombing going on often at short ranges right up to the end of the war.

The Russian front, obviously, was mostly Tactical bombing and it was of immense importance.

Of course in all these Theaters Operational bombing was also done, often with the same light bombers or fighter bombers configured for longer missions (with lighter payloads).

 

[ThomasP]

I have read reports of the Albacore in NA and the MTO being used for attacks on supply dumps and airfields, as well as attacks against troop concentrations, both day and night. At night they were sometimes directed to the target by 1 or 2 Wellingtons acting as pathfinder/illumination flare droppers. During the daytime attacks they were usually escorted when possible. I read in one source (I do not remember which) that ~90% of the ordnance dropped by Albacore squadrons in the NA and MTO campaigns occurred when flying from shore bases.

 

[Wild_Bill_Kelso]

I am in agreement, mostly. By the late 30s the engines were fairly reliable, long lived was different. and in 1939 there was a large discrepancy in power between nations. The US had 1600hp available (just going into production) and the Italians had about 1000hp and everybody else was in-between. This is for engines that were type tested and at least in small scale production ( a dozen or 20 per month)

Also true. A dive bomber needs a heavier structure than a level bombers.

Dive bombers also usually have draggy bomb cradles and often external dive brakes which (unintentionally) act as brakes when not deployed as well...

Also true. High wing loading means high take-off speeds and high landing speeds which means longer airfields. If you want to use a bigger wing for short field performance you have to accept a bit lower speed. If you have one of the more powerful engines perhaps you can do the trade-off. If you are stuck with a lower power engine perhaps you can't.

You have to make some kind of compromise since you will never have all desired features. But if you aren't adding all the extra dive bomber stuff, and you are willing to start out with a small-ish bomb load, I think you could in fact have a fast bomber. The airfield is another compromise of course.

The low powered aircraft also often has to decide between fuel (or range) vs bomb load. A big wing allows for greater load with the same engine. A fast, but short ranged bomber may not be able to reach the desired (or intended) targets making it a poor choice for the money spent. You can't always get everything you want and sometimes niche aircraft have to take 2nd place to more general purpose aircraft.

And many general-purpose aircraft, especially the slow ones, proved to be far too vulnerable to be used successfully in combat. So were just a big waste of time effort and money.

The Breda B. 88, in part, ran into trouble because the engines ran into a wall. They were licensed G-R 14Ks (for the most part) and France had moved on to the 14Ns to get over 1000hp, The Russians were following their own path with the G-R 14K license and went through the M-87 and M-88 engines and they never got them past 1100hp (?).
Without redesigning the whole aircraft The B. 88 was stuck, leave 33% of the bomb load behind? pull one or two of the 12.7mm guns? leave behind several hundred liters of fuel?
A combination?

Wiki makes note of it's extraordinarily heavy and complex construction. I think they overloaded the airframe to the point that it became unstable. They may not have realized it in the earlier period of designing planes which would end up in the war, but a successful airframe needed to be capable of adding 20-40% more weight, at least, which is certainly something which could be a problem with shorter-winged birds.

But that's why aircraft designers make the big bucks. You gotta thread some needles.

 

[Wild_Bill_Kelso]

I have read reports of the Albacore in NA and the MTO being used for attacks on supply dumps and airfields, as well as attacks against troop concentrations, both day and night. At night they were sometimes directed to the target by 1 or 2 Wellingtons acting as pathfinder/illumination flare droppers. During the daytime attacks they were usually escorted when possible. I read in one source (I do not remember which) that ~90% of the ordnance dropped by Albacore squadrons in the NA and MTO campaigns occurred when flying from shore bases.

They were used occasionally but I believe in areas out of range of the (thankfully, short ranged) Axis fighters. An Albacore was dead meat against a Bf 109F or MC 202.