Fast bombers alternatives for 1939-40

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The actual reasons the Bf 162 lost in the competition with the Ju 88 are contained in "Vergleich der Flugzeugbaumuster Ju 88 und Bf 162 in fertigungstechnischer Hinsicht." There were Bf 162 features that the evaluation indicated were desirable, but the BFW resources were unable to meet the schedule requirements. Remember, there were numerous changes in the specifications for this aircraft program and JFM had a larger organization, more capable of meeting the schedule. RLM visits to Dessau in late November and Augsburg in early December, 1937 brought this to light. I have translated the last sentence of the report dated December 9, 1937: "The weapon and bomb equipment of the Bf 162 cannot be seen, which with the Ju 88 (can be seen) through good development technique and proof of good business technique." Remember BFW was still in the process of trying to bring both the 8-109 and 8-110 into production and simply did not have enough engineering resources for a third huge program, anticipated to be much larger than both fighters combined. The Ju 88 was a solid design and the what-ifs of possible better designs (or not!) were less important than trying to meet schedule demands.
ArtieBob
 

At least for the needs of this thread, imperative is on the bomber being fast. That means, for a P-38 sized (if not of the same layout, that is very unpractical here) that the 1000-1200 lb worth of guns and ammo is not existing. A few hundred lbs okay, but not as much as 1200.
Also - the 'normal' bomber of the day, powered by V12 engine, will not have the turbo (minus 600 lbs for two engines?); it will also be without the tricycle U/C (can have 650 lb U/C insted of 850?) - were at another 800 lbs of the weight saved.
 
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And here's a high-speed dive (!!!) four-engine bomber from 1939.



If this project would not have been, the Tu-2 prototype ("FB", '58', '103'/"103U") with a maximum speed exceeding 600 kph had all chances to take off at the end of 1940.
 
Carefully re-reading the original question...

A fast single-engined bomber requires a much bigger engine than what was available in 1939. Think Junkers Ju87 and Fairey Battle with Pratt and Whitney R2800s. If a powerful engine is available for bombers, it is available for fighters, and we are back where we started from.

I am fascinated with the Nakajima C6N Saiun "Myrt". A specialized reconnaissance aircraft much later in the war, it carried a crew of three and a 7.92mm defensive machine gun. Not carrying bombs, heavy weapons and armour, it could out-run contemporary US Navy fighters. Was it stressed for aerobatics? You have to make sacrifices to make things go fast. Quite a few of the sacrifices listed above are not acceptable on a bomber.

For extreme speed and a decent bomb load, we need two engines.

The late thirties saw tremendous increases in aircraft performance, and timing did all sorts of nasty stuff. The Bristol Blenheim was based on the Bristol 142, which exceeded 300mph in 1935, way faster than contemporary fighters. With military equipment, including bombs, it went slower. Meanwhile, the Germans switched to cantilever monoplane fighters with big engines. In the 1930s, the bombers got fast ahead of the fighters, but by 1939, the fighters caught up.

The problem with designing a bombers circa 1938 is that you can have effective defensive armament, or you can be very fast. Doctrine at the time stated that defensive guns were going to be effective. In that sense, the de Havilland Mosquito was the Right Way. The wooden construction does not matter. Getting a pair of big, powerful engines does. In 1939, we are talking twin Merlins or twin DB601s. By late 1940, the people pushing Mosquitos could demonstrate that the guns on the Blenheims and Wellingtons were no match for enemy fighters. How fast is a Leo45 with its turrets extended?
 
Picking the Ju 87 and Battle to prove that the engine power was too low in 1939-40 is too rich.

I love the Saiun. Something like that, but powered with the Bristol Hercules might've been interesting.
If we're to pick further Japanese stuff as role models, the D4Y might be closest to the European taste wrt. the engine choice, and closest to the needs of this thread since it was rather fast. Even more without the things making it carrier suitable.

Armor and other types of passive protection on the Western aircraft in 1939 were more of an exception that a rule.
 
For this thread, the idea is what would it take to make it work.

If the RLM had decided that the Bf162's features fit the bill, then they would have provided for the 162's production by way of other manufacturers.

The Fw190 was manufactured by seven other aircraft manufacturing firms and the Bf109 was also manufactured by other manufacturers as well.
 
All possibilities for trading weight for payload, either bombs or fuel. Off course you do have to factor in 200lbs per crewman (including parachute) but since 3 men is about the max for a light bomber it is not bad.

As far as engines go there are few trade-offs if you yank the turbos from the P-38. The engines used in the P-38D/E (and earlier) used 6.44 supercharger gears instead of the 8.77 gears in the C-15 engines used in the long nosed P-40s. This meant several things all at once. For take-off and low alitide the engines were rated at 1150hp instead of 1040hp. In part because the supercharger to about 50hp to turn and in part because they got more power from the cooler/denser air (inlet temperature was 112 degrees F instead of the 196 degrees of the P-40 engine.) Of course power at 12-13,000ft might really suck. Yanking the guns may just equalize the power to weight ratio for the lower power engines? Maybe you do come out ahead with weight for the turbos gone.
Other choices for the US are the R-1830s and the Wright R-2600 (about 1/2 way through 1940)

For the British you have Merlin X engines until Sept 1940 and a small number of Merlin XX afterwards.

For the Germans you have DB 601s and Jumo 211s.

French and Italians have got nothing. Best the French have got is about 10-15% lower in power than the P-38 engines so either speed (whole reason for the project) suffers or range ro bombload.

1940 Japanese bombers have not much for good engines.

Soviets have got M-103's (?)
They were working on the M-104, M-105, M-106 and M-107 (?) in 1939/40 but the M-105s were showing up in very slow trickle, and needed modifications?
 
tomo pauk said:
Picking the Ju 87 and Battle to prove that the engine power was too low in 1939-40 is too rich.
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Agree but neither the Henley or the Fairey P.4/34 are going to do the job either for the British. Once the 109 shows up as a 340-350mph fighter a single engine 290-300mph bomber, while offering better survivability than than a 250mph bomber, is it really going to keep losses down to a sustainable level. And both of them only carry two 250lb bombs so you need twice as many planes to get the same number of bombs to the target.
Granted neither of them are setting the world on fire with advanced aerodynamics which you desperately need if your engines are limited to just over 1000hp.

I have some doubts about the D4Y1, especially as a guide for a 1939-40 service aircraft. While we can ditch the dive bomber requirement that hurt the real D4Y1 (wings needed beefing up) we are then stuck with a two man plane with no level bombsight and not a good way to mount one, or use it.
A lot also depends on the intended bomb load. Max load of ONE 500kg bomb? which sounds good..............except................what kind of 500kg bomb? A fat high percentage HE bomb or a skinny SAP or low percentage HE bomb? Sources are in dispute about carrying two 250kg bombs.
Picture of model which could be way off?

assuming a 500kg bomb how do you fit two 250kg bombs in there? side by side is not going to work, and I really doubt that one behind the other is going to work either.

A lot may depend on each air forces bomb doctrine. One large bomb is good for ships and Bridges. Not very good for some other things.
It is a "what if". Put a rack under each wing for several small bombs (not one 30kg bomb each side ) but then the speed goes to crap.

And we are back to one of my favorite hobby horses. Field length for 1939-40 land planes. A 1939-40 version might have and 1000hp for take-off and not 1200hp.
The Japanese light carriers they were intended for (?) were the converted sub tenders that could make 26-28kts and while the decks were not big, the planes did not have to clear 40-50 trees at the end of the runway.
Put a bigger wing on it? and accept 10-20mph less speed?

Maybe my old books are off but either this thing was making most planes look really, really bad or some of the numbers are off. 343mph at 4750 meters from an engine that made only 965hp at 4450 meters ( I am accepting RAM) with a plane fatter than a P-40 and slightly larger wing?

Some photos by a forum member.

Meet Judy - D4Y dive bomber in Tokyo

Hi Guys, the latest update to my website is the excellent Yokosuka D4Y at the Yasukuni Shrine in Tokyo. Note that the quality of the images isn't great; the photos were taken with a wee hand held 35 mm film camera many years ago now. warbirds Thanks for looking.
ww2aircraft.net
 

I'd choose the C15 for the fast US bomber. 1040 HP for TO is halfway house between then-new German engines, DB 601A and Jumo 211A, and almost 20% better than on the Merlin III.
The R-1830 powered version might predate the V12 powered version.

Shortround6 said:
French and Italians have got nothing. Best the French have got is about 10-15% lower in power than the P-38 engines so either speed (whole reason for the project) suffers or range ro bombload.
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Then make the bomber even smaller & lighter. Sorta high-wing Fw 187 lookalike, or the Ro.58 with 20% less power and a bomb bay instead of the cannon bay.

Shortround6 said:
1940 Japanese bombers have not much for good engines.
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The initial Sakae engines on a bomber that has the form factor of the Ki-45?
 
Aeodynamics from early 1930s certainly put the handbrake on either of those Fairey or Hawker aircraft. An 1-engined fast British bomber needs to be developed by either Supermarine or De Havilland - the companies that knew how to make racers.

500 kg/1000 lb GP (if we're talking about the Americans or British) bomb sounds great.
It seems like that the options were either a 250 or the 500 kg bomb, while the later radial-powered versions (perhaps only in Kamikaze mission?) carried 800 kg bomb with the bomb bay doors removed.


A lot depends on the expected range? If the target is just a short hop behind the frontline, fuel can be loaded to 50% and more bombs can be carried. If the target is a few hundreds of miles away, keep just the internal bomb.


Design the wing with Fowler flaps. Also, European design does not need the 275 US gal fuel load, let alone the additional 160 gals in the drop tanks; 170-180 will suffice. Engines with better take-off power than the Merlin III will also play their role.
Airfield restrictions for 1937-39 are not the same when Battle was 1st mooted.

All the 'extra fat' was behind the radiators, ie. in their 'shade', so the price in drag will not be paid again.
I'd be okay with 330 mph for the similar Merlin-, 601- or 211-powered design. It will be faster than the bombed-up Bf 109, let alone for the bombed-up Bf 110, that seem to be fared the best among the LW bomb-luggers during the BoB.
 
tomo pauk said:
Picking the Ju 87 and Battle to prove that the engine power was too low in 1939-40 is too rich.
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My point is that if your single-engined bomber uses an engine equivalent to that of opposing single-engined fighters, it will be slower. Really, really good design might make up for some of this. The real solution for a fast light bomber is two engines, equivalent to what the fighters got. The Bristol Blenheims which got massacred in 1940, were powered by 840hp radials. 1000hp Merlins would have also been better streamlined. The 1400hp Hercules engines on the Beaufighter were a much better solution, especially since the Hercules engines got quite a bit more powerful.

Roy Fedden was trying to set up manufacturing of the Centaurus engines in Canada in 1940. There was no demand, so they shut him down.
 
tomo pauk said:
Aeodynamics from early 1930s certainly put the handbrake on either of those Fairey or Hawker aircraft. An 1-engined fast British bomber needs to be developed by either Supermarine or De Havilland - the companies that knew how to make racers.
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Racers rarely make good combat aircraft. I am not sure that some companies had the 'secrets' to speed. In a lot of cases the companies were trying to satisfy bunch of conflicting requirements. And the British Air ministry could sometimes (more than sometimes) ask for more than a liter to be put in a 1/5 liter bottle.

DH Don. 250 ordered (off the drawing board?) but after the prototype flew and some trials the order was cut to 50 and 20 of them were 'finished' as ground instruction airframe without engines. Maybe not the guys you want to design your high speed bomber? or maybe just the guys if you can keep the Air Ministry guys from adding a ton of "nice to have features but are now part of the design or no orders"
tomo pauk said:
A lot depends on the expected range? If the target is just a short hop behind the frontline, fuel can be loaded to 50% and more bombs can be carried. If the target is a few hundreds of miles away, keep just the internal bomb.
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Yes, somebody should have figured out that a single engine bomber was not going to work for strategic bombing (1000 mile or longer range over land).
Problem for the British is that, as mentioned in other threads, is that the British didn't believe that the 1000lb bomb was needed until 1939/40. They only built 159 of them in 1940 and that was the low HE GP bomb (about 33% HE).
some early British bomb dimensions (rounded off)
Bomb....................length................diameter
1000lb....................220cm..................41cm
500lb......................175cm..................33cm
250lb......................138cm..................26cm

And we start to see some of the problem in designing bomb bays. You can't even fit two 250lbs in the same width as a single 1000lb bomb. You don't what bombs hitting each other on the way out and you need room for a hand to around the side of the bomb to check on the attachment lugs and safety wires (or you need to be able to reach through holes in the bomb bay roof)
Germans don't quite have this problem although the 250kg bomb was a lot more common than the 500kg bomb earlier in the war.
tomo pauk said:
Design the wing with Fowler flaps.
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Fowler flaps are really good for getting you into the airfield, while somewhat used for getting out they are a lot less useful

I don't think you want that kind of flap deflection (air brake) when trying to take-off (get up to flying speed). extreme example but Fowler flaps are not a substitute for engine power for take-off.
tomo pauk said:
Airfield restrictions for 1937-39 are not the same when Battle was 1st mooted.
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No they are not but they didn't improve a whole lot in the late 30s. That whole scheme about catapulting Manchester bombers? British did a lot of work in the late 30w but then needed more and they were surprised when they went to France and saw what the French fields they were given were like (If they had been good field the French would have kept them)
tomo pauk said:
I'd be okay with 330 mph for the similar Merlin-, 601- or 211-powered design. It will be faster than the bombed-up Bf 109, let alone for the bombed-up Bf 110, that seem to be fared the best among the LW bomb-luggers during the BoB.
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And we still have not figured out the attack method, that is to say aiming the bombs and just flying over the area and dropping the bombs somewhere is a several kilometer radius of a local church steeple and offering prayers to god for a hit
You don't have to dive at over 60 degrees and use dive brakes but you need something and something should be better than the what the British did. Their bombsight on the Battles and Blenheims didn't have any stetting for less than 3000ft so the bomb aimer was useless and it was up to the pilots judgement as to when the drop the bombs but they rarely practiced at low altitude and using the pilots judgement.

The whole thing needs to be, in modern language, integrated. It is not enough to fly fast and carry bombs. You need the right bombs for the right targets and you need a way to delivery them with a fair degree of success and you need to practice it.
 
Howard Gibson said:
My point is that if your single-engined bomber uses an engine equivalent to that of opposing single-engined fighters, it will be slower.
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That will depend on a lot of things. Pointing out to the slowest of the slow bombers as being, well, slow, does not contribute to the discussion.
At the end of the day, I'm okay if the bomber is slower by a tad.

I agree with the notion that the Merlin- or Hercules-powered bombers would've stood the better chances in 1940. Yes, the aircraft designer still has to play his part.

Howard Gibson said:
Roy Fedden was trying to set up manufacturing of the Centaurus engines in Canada in 1940. There was no demand, so they shut him down.
Click to expand...

Source?
 
Howard Gibson said:
Roy Fedden was trying to set up manufacturing of the Centaurus engines in Canada in 1940. There was no demand, so they shut him down.
Click to expand...
My problem with this is that they really had not figured out how to build the Hercules in quantity for much of 1940. Until they figure that out building Centaurus engines just gets you larger, more expensive engines that have really, really short lives. Some early Hercules engines had to be pulled with running times in the 20 hour range. Fouled spark plugs at best and sized sleeve valves at worst with sheared sleeve drives.
If there was enough tooling (and manpower) for a factory to build Centaurus engines there was enough tooling and manpower to build a plant to make Merlin's or P&W R-2800s
Fedden may have wanted a plant and was convinced in his own mind that this was a good idea. Other people may not have been convinced or wanted the resources for other things.
 
Shortround6 said:
Racers rarely make good combat aircraft.
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Companies make combat aircraft.

Shortround6 said:
I am not sure that some companies had the 'secrets' to speed. In a lot of cases the companies were trying to satisfy bunch of conflicting requirements.
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Some companies were better in coming out with faster aircraft than other companies in the same time and with the same engines.Often while using same theoretical knowledge. See eg. the LW contest for the 1-engined fighter that saw Bf 109 as a winner.
Granted, sometimes even the 'best' companies produced ducks/clunkers, with or without help of the costumer...

... as in this case (and a lot of others). An all-singling all-dancing trainer twice the size of an Continental fighter of the day, with 500+ HP.
Take a look at other aircraft DH was making, and expecting from them to make a fast bomber is not a long shot. A company used to cut the drag & weight will rebound faster after a hiccup (too draggy & otherwise uninspiring aircraft) than a company used to make sedate aircraft.

Thank you for the numbers.
Blenheim went from 4x250 lb (4x117 kg) to 8x100 kg of bombs in the bomb bay the Finnish service. A bomb bay that is 70 cm wide will comfortably held the 250 lb bombs while not being too wide even for a 1-engined bomber. Enlarging the bomb bay and/or deepening the doors can be done later, as it was case in many bombers, like the Blenheim or Mosquito.

Shortround6 said:
Fowler flaps are really good for getting you into the airfield, while somewhat used for getting out they are a lot less useful
Click to expand...

I'd say that they are a good deal useful for taking off. Unlike a lot of flap desiges of the day.

Shortround6 said:
I don't think you want that kind of flap deflection (air brake) when trying to take-off (get up to flying speed). extreme example but Fowler flaps are not a substitute for engine power for take-off.
Click to expand...
I'm okay with Fowler flaps reducing the required take-off distance by, say, 20%.
Shortround6 said:
And we still have not figured out the attack method, that is to say aiming the bombs and just flying over the area and dropping the bombs somewhere is a several kilometer radius of a local church steeple and offering prayers to god for a hit
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How good were the bomb sights on the bombed-up Bf 109s and 110s?
But I can settle for a periscope sight...

... or indeed dive bombing.
Something like the undercarriage of the P-36, but reinforced, might serve as the dive brake.

Shortround6 said:
The whole thing needs to be, in modern language, integrated. It is not enough to fly fast and carry bombs. You need the right bombs for the right targets and you need a way to delivery them with a fair degree of success and you need to practice it.
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Agreed.
 
Howard Gibson said:
By Jupiter, by Bill Gunston.

Wilfred Freeman is presented as a bit of a villain in Gunston's book. This is awkward if you are used to hearing the de Havilland Mosquito described as "Freeman's Folly".
Click to expand...
Was there any UK factory actually making (in series, not as prototype) Centaurus engines in 1940?
 
tomo pauk said:
ome companies were better in coming out with faster aircraft than other companies in the same time and with the same engines.Often while using same theoretical knowledge. See eg. the LW contest for the 1-engined fighter that saw Bf 109 as a winner.
Click to expand...
Sometimes the winner ignored one or more requirements and hoped that the sparkling speed performance would overshadow the field performance
tomo pauk said:
Enlarging the bomb bay and/or deepening the doors can be done later, as it was case in many bombers, like the Blenheim or Mosquito.
Click to expand...
Later British 500lbs got cut down tail fins.
early 500lb......................175cm..................33cm
late 500lb.........................144cm.................33cm
But counting on that in the design process???
But that is how the Mosquito got to hold four 500lbs in the bomb bay.
tomo pauk said:
I'd say that they are a good deal useful for taking off. Unlike a lot of flap desiges of the day.
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Yes some flap designs were near worthless (or required tricks) like the Spitfire. Hurricane actually got some benefits from it's flaps, primitive as they were.
P-47s is supposed to have Fowler flaps, but like with many things, actual effects vary. The P-47 flaps only move a few inches rearward and then hinge down

I am not going to argue about if this a Fowler frap or a slotted flap or some mix. Better than a regular flap but at 15-25 degrees you don't get the wing area increase of some Fowler Flaps. You also have pay for the increased weight and complications.
Problems are
A
All of these max increases in lift are at angles of attack that nobody is going to use while taking off (unless you keep the tail wheel down until lift off).
Some are better than others for take-off.
 
Does Fokker G.1 fit into the scenario?
Because I love this bird.
In cooperation with the British.
Changes to the historical design:
- engines Merlin X with further upgrade to Merlin XX
- nose section redesigned in the style of Me 210/410
- longer bomb bay
- navigator/observer seat as in Mosquito
- longer fuselage?
- redesigned wing to reduce drag?
- bombsight? probably, none in 1939, but Mark III or Mark XIV added when available.
 
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