1938-41 fighter-bombers?

[Shortround6]

I wonder if the Airacuda could have been repurposed as a fighter bomber? Put a bomb bay like the A-20's in the fuselage while keeping the wing bays, replace the manned 37's with a fixed 20mm and 4 .50 M-2's cut the crew to one, maybe two. Replacing the V-1710 with R-2600's might be good too.

Hmmm, we just need to cut about 1/3 of the wing area, a whole new fuselage, new engine nacelles, new engines, new landing gear? trim the tail to suit the smaller airframe and......well golly gee, we have a whole new airplane

 

[wlewisiii]

Hmmm, we just need to cut about 1/3 of the wing area, a whole new fuselage, new engine nacelles, new engines, new landing gear? trim the tail to suit the smaller airframe and......well golly gee, we have a whole new airplane

True enough. Happened a few times though if you look at the differences between prototypes and production aircraft.

 

[jetcal1]

True enough. Happened a few times though if you look at the differences between prototypes and production aircraft.

I wonder how many parts were common between a Spitfire MKI and a MK47.

 

[Kevin J]

None?

 

[Kevin J]

None?

 

[jetcal1]

None?

Maybe the clips for the emergency axe.

 

[Shortround6]

Same drill as before: countries adopt a fighter-bomber idea a few years before it was wideaspread historically, perhaps instead of light bombers and/or dive bombers? Fighter-bomber could be defined as an aircraft designed 1st fighter, that can be easily modified to carry bombs and other ordnance to attack ground forces; once without external ordnance, it can hold his own against other fighters of the day; 1 or 2 engines.
What implementations might work better than the others? What countries could get ahead with design, production and use of FBs? A modification of historical fighters or a brand new airframe? If the doctrine or policy need to be changed in order to have FB in service, change that into doctrine/policy that favors the FBs instead of something else.

Some could-have-beens for purposes of the thread:
- P-36/40 with undercarriage modified to double as airbrake and extra protection for cooler(s)
- Hurricane with beard radiator (thus reducing the length of piping for coolant and oil), some protection for coolers, Merlin VIII
- Hurricane with Hercules engine
- pre-1940 twin, powered by two Mercury engines, size of Whirlwind
- if we have money to burn - a twin with two Merlin/DB 601/V-1710 engines; Potez 63 series with HS 12Y engines and better armament
- 1-seat Defiant, with bombs and 4 .303s or two Hispanos, otherwise modified as Hurricane above
- MB-2, bombed-up (ducks for cover)

This may be worth a revisit with the A-36 thread.

Now the A-36 kept a large amount of the structure and engine installation. The further you go from the original airframe and engine the more delay and the higher costs.
We also have the engine problem of the 1938-41 engines, and the fuel.
A-36 had 1942 engine and 1942 fuel. The Allison was on it's 3rd crankshaft and crankcase and could depend on 100/130 fuel.

Keeping things simple for the British you have 3 likely contenders.
The Spitfire, but you don't have enough.
The Hurricane, most likely.
The Gloster Gladiator.

Historically most of the further out ideas probably won't make it to 1941 and would be hard pressed to make it to 1942.
You don't have enough Hercules engines to put into much of anything in 1941.
The Defiant needs a lot of rework, it may look the same (or nearly) outside but you need a lot detail changes inside, you can't even the leave the fuel tanks in the same location.
And since the first Production only takes place in 1940 you won't wind up with more that a few squadrons until late 1941.

You have several technical problems.
1, is the poor choice of propellers the British have.
2, is the poor choice of bombs the British have.
3, is the poor choice of propellers the British have.
4, is the small wings/flaps in some of the choices.
5. is the poor choice of propellers the British have.
6. is the historic choice of either Merlin or the Mercury engine.
7. is the poor choice of propellers the British have.

The props in 1938-39 really affect the take-off run and the ability to lift a load of bombs/fuel.
The 2 speed props help in 1940 but actual maneuverability/performance at low altitude or less than full speed is still severally compromised. If you are are cranking up your flaps/landing gear when you change the prop pitch to full angle (course) your climb and maneuverability at low level is still compromised severely. Using a low boost/low altitude engine is only going to help so much.

For the bombs the RAF only dropped 159 1000lb bombs in all of 1940. Off course with the engines availability at the time your fighter bomber/dive bombers won't be able to carry the 1000lb anyhow.
Pretty much your choice of bombs are going come down to 250lb bombs and 40lb bombs. The British dropped about 4 times the number of 250lb bombs in 1940 that they did in of 500lb bombs. Again with the engine choices available in 1938-1940 trying to carry a pair of 500lb bombs is probably not going to go well on a fighter size wing.

We may have to go country by country.

 

[Shortround6]

Going to France (may get back to England

You have 3 basic fighters
The MS 406
The D. 520
The MB 152
All are about the same size. From 170 sq ft to 186 sq ft of wing and about 5600lb to 6200lbs.
Since the 109 showed you could hang a 550lb bomb from a plane that size the French planes should be able to do the some thing.
It may require a bit of cutting and filing though.

in 1938 The French do have a better propeller on the MS 406 than the British but the engine, HS12Y, is a bit questionable. There were other HS12Y engines on offer with more power at sea level/take off but they had attitudes as low or lower than the Merlin VIII in the Fulmar. They also had less power. The 109 had several hundred more HP to get that 550lb bomb off the runway.
Perhaps you can add a bit of wing to wing root?
The D. 520 needs either a modified cooling system or to put a bomb out on each wing.
The MB 152 offers an air cooled engine and the most powerful at sea level. but the landing gear just about touch under the fuselage. Again, add wing root extensions or just put a 220lb under each wing?

There were a few old aircraft that might have worked in 1938-39.
Loire 46

210sq ft of wing and a 931hp engine. Perhaps a new airplane could use a more modern version of the engine?

Basic problem for the French is the engines are just a bit low powered.
The French did have a few dive bombers but they are not fighter bombers.

with a 266sq ft wing and an under 700hp engine things were not good, adding a higher power engine was easy but that runs into the industrial base. If you can't build enough engines for fighters can you build fighter bombers at the same time?

 

[Shortround6]

Moving our tour to Italy we see the same problem but also what the Italians did about it.
You have low powered engines which limit the desired payload.
Or you have to use two engines which runs up the cost per plane.

Italians did use a number of older fighters in close support/fighter bomber roles and the maneuverability of the older planes did offer some protection.
Bombload was often limited to a pair of 100kg bombs (and sometimes just a pair of 50kg bombs).
How many of them were flying in 1938-41 I don't know.

 

[Fatboy Coxy]

I'm listening to you Shortround6, waiting Japan's turn!

 

[ThomasP]

For the Italians I nominate the CR.42 DB.

The radial engined CR.42 airframe entered service in 1939, so historical timeline wise a DB601 powered version would probably not be available before 1940 - if there were DB601s available. The low wing loading combined with the power of the DB601 (1000+ BHP) would allow a useful bomb load, and it had a respectable speed for the early-war period (probably around 320 mph in service). Some standard CR.42 were modified to carry a 100 kg bomb under each wing, so it might be possible to cary 250 kg bombs with some additional strengthening? Maneuver wise it would have been in the A6M2 category, so defending itself after bomb drop would have been feasible.

 

[tomo pauk]

Some that might've worked well, some perhaps being so-so:
- P-36 as-is
- P-36 with R-2180A
- P-35 with a 1000 HP R-1830 instead of the 850 HP engine
- Hurricane with Pegasus
- Spitfire with the 1000 HP Dagger
- MB-152 series (it still baffles me why it was so slow as a fighter despite a reasonable power and small size)
- I-16 as-is
- Re.2000, just build it earlier, there is no ground-breaking technology in these
- He 112 with BMW 132

 

[OldGeezer]

There used to be a big banner on the wall in the engineering office where the F-15 was designed at McDonnell Douglas in St Louis that said "Not A Pound For Air To Ground" or so the old-timers told me when I arrived there in 1979. But F-15E turned out to be a winner. I also worked around the fringes of the F-14A when I was a civilian employee at the Naval Air Rework Facility in Norfolk VA. My F-8 group was just next door to the F-14 group and across the hall from a large bunch of engineers from Grumman who were on loan to us to help ease the introduction of Tomcats into Navy service. Based on what I was hearing from them, the suspension of air-to-ground mission capability was overwhelmingly due to two things: Fear of putting the Navy's most expensive aircraft (by far, at the time) into the highest-threat area where it would run much higher risk of being lost than it would in a CAP/intercept environment, and fear that any aircraft shot down over land would mean the highly sensitive AWG-9 radar and possibly the AIM-54 Phoenix missile could fall into enemy hands. It's hard to realize today just how sensitive those were felt to be, but we got vivid proof when an F-14 went into the North Sea in 1976. Rather than risk the Soviets recovering the wreckage, the Navy went grappling around until they snagged it and dragged it to the surface, then they loaded it into a Super Guppy and flew it to Norfolk, where I was at the time. The Guppy had an engine failure on final approach, so it sat outside our flight test hangars for something like 2 weeks, waiting for a new engine to be flown in and fitted. I got to sit in the pilot's seat, which I'll never forget, and when I went into the back it was like walking into a cathedral or something, just a huge open space with structural members soaring overhead. Unforgettable experiences for a very junior engineer! I saved a clipping from the local paper, which shows number 2 engine space opened up. When it finally left, I happened to be at the flight test area for something else, and I watched what turned into the weirdest, scariest takeoff I've ever seen to this day - but that's a whole other story!

 

[Shortround6]

Some of these planes could have been better "fighter" bombers if they had used engines optimized for the low altitude area.

You also have to be very careful with some of the Pre WWII American engines as they sometimes weren't reffered to by take-off power or even in "max" power.
The engines (R-1830-9) in the original P-35 for instance were rated at 950 hp for take-off and 850hp at max continuous. There was no Military Power or 5 minute or 15 minute ratings.
The engines in the P-35A (R-1830-45) were rated at 1050hp for take-off and 900hp max continuous but they were rated at 12,000ft and not 8,000ft. they also weighed over 100lbs more.
P-36 needs some work done on the wing, Curtiss advertised up to 800-850lbs of bombs under the the Hawk 75 but next to nobody tried it. The US P-36 and the French Hawk 75s had trouble with take-offs and landings as it was.
R-2180 was about 200lbs heavier than the R-1830s used in the P-36. By the time you get to the prop and the accessories you have more powerplant than the Allison in the P-40.

I am afraid the idea of repowering some of the Merlin powered aircraft with radials (or the Dagger) is trading one problems for another.
Yes you get rid of the cooling system for reduced vulnerability but you also saddle the plane with much reduced performance in the form of much higher drag, Will the slower speed, slower climbing planes suffered higher losses?
A P-36 had about 22% more drag (or less exhaust thrust) than an Allison.
The engine installation on the P-36 was a masterpiece compared to the Bristol Radials.
As for a Dagger on a Spitfire?

The Herefords at all kinds of trouble with the Dagger engine. They couldn't even warm up properly without turning the planes to point into the wind, and even then it was iffy.
Engine temperatures would go critical before the engine oil was up to temperature.

If you want British fighter bombers just slap some Merlin VIII engines out of the Fulmar into them for a very useful increase in take-off power.
Off course unless you can come up with the Constant speed props most British fighter bomber ideas are over before they start.
Exception might be sticking a two pitch prop on a Gladiator and beefing up the bottom wing a little.

 

[Shortround6]

As far as the He 112 with a BMW 132 engine.

lets put that on the nose of the He 112

You might get a ground attack plane out of the result but you can forget being able to dog fight on the way home. You are too slow.

 

[GrauGeist]

He 112 with BMW 132

Why?

By 1938, the He112B-2 had the Jumo210Ga, which gave it good performance.

Of course, with a DB601, it's performance would have been stellar, but we know that wasn't going to happen.

 

[tomo pauk]

As far as the He 112 with a BMW 132 engine.
lets put that on the nose of the He 112

You might get a ground attack plane out of the result but you can forget being able to dog fight on the way home. You are too slow.

Why?

By 1938, the He112B-2 had the Jumo210Ga, which gave it good performance.

Of course, with a DB601, it's performance would have been stellar, but we know that wasn't going to happen.

Yes, the He 112 with the DB 601 will not happen, especially if the job is to be a fighter-bomber. For any 100 Jumo 210 produced, there is probably 90 Jumo 211 less produced?
The He 112 with BMW 132 would've had the appearance, size and engine power as the CW 21, and better load-carrying capacity than He 112 due to 20% better power at low altitudes.

 

[Geoffrey Sinclair]

For the bombs the RAF only dropped 159 1000lb bombs in all of 1940. Off course with the engines availability at the time your fighter bomber/dive bombers won't be able to carry the 1000lb anyhow. Pretty much your choice of bombs are going come down to 250lb bombs and 40lb bombs. The British dropped about 4 times the number of 250lb bombs in 1940 that they did in of 500lb bombs. Again with the engine choices available in 1938-1940 trying to carry a pair of 500lb bombs is probably not going to go well on a fighter size wing.

Interesting, AIR 19/927 says Bomber Command dropped 153 1,000 pound 20,266 500 pound and 61,786 250 pound bombs, the raid sheets (AIR 14/2664 to 2670 and 3360 and 3361) come to slightly different totals.

So does the 4 to 1, 500 pound to 250 pound bomb ratio, include Coastal Command and Mediterranean Units and where can their bombs dropped figures be found? Also any ideas for where to find the figures for bombs dropped by 100 group?

 

[Admiral Beez]

Sure a Whirlwind would meet the requirement.

I'd want to increase the ammunition capacity, and reliability of the 20 mm guns. Possible utilizing a serpentine belt (like the below model of the Mosquito) but relocated to behind the pilot, moving the radio or other weight forward to compensate.

Otherwise the ammunition of the Whirlwind is only good for perhaps a single pass at a ground target and a burst at an enemy fighter before fleeing the scene.

 

[Shortround6]

That is because of the 60 round drums (which were good for 6 seconds of firing time)
Search the internet or this forum. There was a test setup of a Whirlwind with air powered magazines that held about 115-120 rpg.
The air power system didn't work well but there was more than enough room to fit 120 rounds per gun in belts in front of the pilot.
They even had three .303 guns mounted on top of the four 20mm guns.