1937 to the late 1941: fighter bombers instead of 1-engined bombers?

tomo pauk

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It was suggested,IIRC by S Shortround6 at another thread, that Allies might've been better advised to procure fighter-bombers instead of the 1-engined bombers in the similar time frame. So here it is - 1-engined bombers, like the Ju-87, Ba.65, Su-2, Il-2, Battle, A-24, different Japanese 1-engined bombers are not proceeded with, instead the respective countries make and operate fighter-bombers. Whether these are modified historical fighters, or bespoke A/C. All while using the engines, aerodynamics, materials and weapons as it was historically the case; no hand-waving of thousands of the best engines just for this, the FBs will mostly be using what was historically used on the bombers that don't get produced, or the equivalents/modifications available.

Yes, for some countries/AFs this will require changes in doctrine. Obviously the FBs designed in 1937 will be less capable than the ones mooted in 1940.

For the French, since they were mostly using two-engined tactical bombers, the fighter bombers replace those, but can use bigger & better engines.
 

tomo pauk

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Germany - the He 112A has probably an advantage here since it had a bigger wing than the Bf 109. Once the Jumo 211 is available, install that so both bomb load and performance without the bomb(s) is acceptable.
Italy - something along the lines of Re.2000, or the 'monoplane CR.42'?
Soviet Union - they were already operating the biplanes and I-16 as fighter-bombers. For the new generation, something like I-180 with a bigger wing? Upgrade with M-82 engine when available.
USA - the P-36 looks the part, and was already advertised as a fighter-bomber by the manufacturer. Move to the 1200 HP R-1830s when available.
 

tomo pauk

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Since we have saved a great of deal of BMW production in the current thread, perhaps we can install the BMW 801s on the Bf 109? The Bf 109X fuselage with wings from Bf 109T to keep the wing loading manageable (keen eye will notice the spoiler on both wings, so sue me ;) ). Pictures of both components nicked from Wikipedia. Two MG 151/20s, two MG FFMs as guns' armament; no cowl guns.
Advantages over the Bf 109 in the fighter-bomber role include the lack of coolant radiators, has an armored oil cooler, more power down low, wider track (2.5m vs. 2m) due to the wider fuselage, better cockpit canopy, greater guns' firepower. Disadvantages vs. the Bf 109 is greater weight and size (although it is still a bit smaller and lighter than the Fw 190), new fuselage needs to be made. Also consumes more fuel per air mile than the V12s - the no free lunch applies as ever. Bigger fuel tank is installed.

109 801.jpg
 

ThomasP

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Maybe the CR.42DB (CR.42 with a DB601A engine) for the Italians? First flight was in March 1941 and first production order for 150 airframes was placed in May 1941, but a shortage of engines resulted in the order being cancelled. Vmax clean was 320 mph during tests.

CR.42DB color.jpg



The standard CR.42 was used as a fighter-bomber so I can only assume the DB variant could be even better at the job.
 

tomo pauk

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Maybe the CR.42DB (CR.42 with a DB601A engine) for the Italians? First flight was in March 1941 and first production order for 150 airframes was placed in May 1941, but a shortage of engines resulted in the order being cancelled. Vmax clean was 320 mph during tests.

This should easily beat the Gladiators, and give Hurricanes something to think about. Shortage of DB 601 engines was indeed the kicker. Original CR.42 was cleared for up to 2 x 160 kg bombs.
If the DB engines were in good supply - the Re.2001 was supposed to do 337 mph, and was eventually cleared for up to 630 kg bomb. These will also be capable to hold their own against the P-40s and tropicalized Spitfires.
 

tomo pauk

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For the RAF: finally a place for the MB.2?
The Dagger VIII engine was making it's best power down low - 1000 HP at 8750 ft, but just 800 HP at 15000 ft - making it better for the low altitudes where we can expect the FB to be used, and not so good for bombing Germany from 17000-18000 ft. Does not draw on Merlins' and Hercules' production - RAF has barely a place for the Dagger either as a fighter engine or a bomber engine. Also no draw for production of Spitfires and Hurricanes ordered for the FC.
Being air cooled makes it less susceptible to the battle damage, does not add the drag & weight via the coolant radiator.
MB.2 might get the retractable U/C for lower drag, even it the proposed system was barely more streamlined than what P-35 had. Nip & tuck is still needed, like a better prop, exhausts (pointed backward), protection for pilot and fuel.
 

yulzari

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For the RAF: finally a place for the MB.2?
The Dagger VIII engine was making it's best power down low - 1000 HP at 8750 ft, but just 800 HP at 15000 ft - making it better for the low altitudes where we can expect the FB to be used, and not so good for bombing Germany from 17000-18000 ft. Does not draw on Merlins' and Hercules' production - RAF has barely a place for the Dagger either as a fighter engine or a bomber engine. Also no draw for production of Spitfires and Hurricanes ordered for the FC.
Being air cooled makes it less susceptible to the battle damage, does not add the drag & weight via the coolant radiator.
MB.2 might get the retractable U/C for lower drag, even it the proposed system was barely more streamlined than what P-35 had. Nip & tuck is still needed, like a better prop, exhausts (pointed backward), protection for pilot and fuel.
Also Martin Baker made a far better job of cooling it than Napier.
 

Shortround6

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Also Martin Baker made a far better job of cooling it than Napier.
did they?
Seems to be some confusion as to which engine the M.B.2 got. Or maybe it had more than one?

It seems to have been the Dagger IIIM of 825hp at 4000ft, 2.25lbs at 4000rpm. and 700hp for take-off at 3,500rpm and 3.5lbs boost. I don't know if this was because of the fixe pitch prop.

The 1000hp engine was the VIII but that doesn't seem to show up until the Hereford. there were a number of changes, one of which was spur reduction gear.
raf-bomber-command-1940-hu104644-22e6d1-640.jpg
handley-page-hp52-hereford-l6003-9892781.jpg.webp

45-_Handley_Page_Hp.52_Hampden_and_Hereford._CH155.jpg

Note that the top of the prop spinner is almost inline with the upper exhaust stacks while the lower edge of spinner is offset above the lower exhaust.

I don't know how bad the Hawker Hectors were for cooling. It the is the Herefords that get most of the bad press.
The Dagger VIII got a new supercharger, and is also supposed to have gotten increased cooling fin area. Considering they were trying to pull about 200hp (30%) more out of it at take-off that is understandable.

If the MB 2 reached it's performance on the lower power engine that is very commendable, but the service use of the higher powered version of the engine was pretty dismal.
Maybe it could have been fixed or maybe it needed a lot more work (like even more fin area and other changes).
 

tomo pauk

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From the current thread:

You are going to be hard pressed to keep it smaller than a P-40.

1939-40 air cooling and lack of exhaust thrust (design perspective)
1900lb engine.
The US is going to want at least 200 US gallons of fuel (P-36 has around 160gal without drop tank and without self sealing. P-39 was supposed to have 200gal before self sealing)
As you have said, it is a thirsty engine (I agree, 150 US gal/hr at 1275hp at 12,000ft, more at full power)

Just for context
XSB2C-1 photo may date from Aug 1941 as several features in the photo series date from then.
Brewster Buccaneer prototype, summer of 1941
Just the state of the art in cowling, exhaust in 1940-41 in the US.

You need every bit of the 1400hp to to overcome the drag compared to the V-1710 in the P-40.
Granted you can make the Fuselage considerably smaller and no cowl guns) but you can't stick this thing on a P-36/40 without longer landing gear legs.

The early A-20 were pretty zippy, despite the big radials, heavy weight, thick (18% t-t-c root) and big wing, lack of finesse wrt. exhaust stacks, and it's portly fuselage. 333 mph for the A-20B at 5000 ft (2x 1570 HP used), 349 mph at 12050 ft (2 x 1400 HP). That is within 2+- mph vs. the gun-armed Mosquito per this test at these altitudes, +12 lb boost used, ie. with ram ~1300 HP at S/L, and ~1400 HP at 12000 ft. The V-1710 was much worse than that in 1940-41, 1000-1150 is the best what can be expected when going from SL to 12000 ft.
Sometimes just having the brute force is an advantage; finesse - like the better exhausts - can come in later, so can a 1700 HP R-2600.
 

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