1938-41 fighter-bombers?

[SaparotRob]

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.

View attachment 655487

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.

That is a beautiful piece of work. Really, really nice.

 

[Shortround6]

The French actually devoted quite a bit of attention to fighter bombers/attack aircraft during the 1930s.
A lot of this attention was biased toward or called light bombers so it gets a little to difficult to figure out.
Since the French also tended to to use the GR 14M engine for a lot of these efforts you had a two engine, multi seat aircraft with about 1400hp which means the results were not spectacular.

Br 693 around 230 built.
one 20mm gun, two 7.5mm guns in the nose. a single 7.5 gun out the top and one out the bottom (same gunner) and around eight 50kg bombs.
top speed was about 300mph but that was well above sea level.

The French also used some of these.

the bomber version used eight 50kg bombs inside the fuselage and requirements changed from a 2 man crew to a 3man crew.
Both Planes were initially equipped with HS 14 cylinder radials but the unreliability forced the replacement by the GR 14M.
Again these are small airplanes, wing area of about 350 sq ft, gross weight around 10,000lbs depending on the model. power of 1400hp so their performance compared to a 1200-1500hps single engine plane was pretty basic.

 

[yulzari]

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?
View attachment 655434
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.

Many years ago I spoke with a de Havilland wartime engineer who was tasked with reporting upon the Napier Dagger installation on the Hereford. He said that Napiers design was all about stuffing air into the intake but de Havilland had long settled upon the key factor being optimising it for low pressure. Crudely put, once that was done the air would find it's own way in. He reckoned that a redesigned cooling system would sort out the overheating issue and be controllable to prevent over cooling as well leaving it to perform at the advertised power as needed.

 

[Shortround6]

There is something to what you say, but the Dagger had some real problems.
Somewhere I have a diagram and head and cylinder temperatures for a 6 cylinder Ranger engine. Shows the cylinder head and cylinder barrel temperatures for all 6 cylinders. Air came in the front on one side, crossed over between the cylinders and out the other side, exit was only on one of the cowl.
Temperatures were all over the place. The rear cylinder was cooler than most of the other cylinders, the worst were somewhere in the middle and the hottest cylinder barrel was not the hottest cylinder head.
You also had two 90 degree bends in the airflow getting the air to flow from one side of the cylinder bank to the other and then back out through the rear exit. Even a two row radial was was easier to sort out
Dagger had four 6 cylinder banks.
It wasn't just getting the right amount of air through the engine, it was getting the right amount of air through each and every one of the cylinder gaps and ends.

You only need 1 cylinder out of 24 to overheat to wreck the engine.

 

[yulzari]

In respect of the OP one might look at the period fighters to be the putative fighter bombers. For example, the Hurricane, on it's period engine and a fixed pitch 2 bladed propellor is not going to be hauling much of an extra weight off a small wet grass field in 1939 France. A 1942 Hurricane II is another story. To lift it's bomb load the 1939 Hawker Henley needed a lot more wing area than than a Hurricane with the same power. One might also look at the Ju87 and it's wing area versus a 109.

Therefore I conclude that the chosen OP period was one where a contemporary fighter could not carry a large enough bomb load to act in the modern understanding of a fighter bomber. To lift that load needs more wing area and that compromises the fighter part of the role. Looking at period aeroplanes one finds the role being thus split towards either one role or the other.

It was not until 1942 engine developments in fighter airframes allowed the excess load to combine the two parts of the role into one aeroplane. 1941 saw the beginnings of this.

 

[yulzari]

There is something to what you say, but the Dagger had some real problems.
Somewhere I have a diagram and head and cylinder temperatures for a 6 cylinder Ranger engine. Shows the cylinder head and cylinder barrel temperatures for all 6 cylinders. Air came in the front on one side, crossed over between the cylinders and out the other side, exit was only on one of the cowl.
Temperatures were all over the place. The rear cylinder was cooler than most of the other cylinders, the worst were somewhere in the middle and the hottest cylinder barrel was not the hottest cylinder head.
You also had two 90 degree bends in the airflow getting the air to flow from one side of the cylinder bank to the other and then back out through the rear exit. Even a two row radial was was easier to sort out
Dagger had four 6 cylinder banks.
It wasn't just getting the right amount of air through the engine, it was getting the right amount of air through each and every one of the cylinder gaps and ends.

You only need 1 cylinder out of 24 to overheat to wreck the engine.

I agree. Napiers worked hard at creating the right answers but they were asking the wrong questions. My acquaintance commented that the Dagger needed an integrated system with the wing design somewhat like the Albatros reverse flow. I have no basis upon which to comment otherwise but I can see what he means. It made me think of the Centaurus reverse flow systems of the Brabazon. Not a radial 'change engine mounts as long as the centre of gravity permits' engine type change like the Taurus to Twin Wasp on the Beaufort (except the Twin Wasps all ended up on the seabed of the North Atlantic).

 

[tomo pauk]

Therefore I conclude that the chosen OP period was one where a contemporary fighter could not carry a large enough bomb load to act in the modern understanding of a fighter bomber. To lift that load needs more wing area and that compromises the fighter part of the role. Looking at period aeroplanes one finds the role being thus split towards either one role or the other.

It was not until 1942 engine developments in fighter airframes allowed the excess load to combine the two parts of the role into one aeroplane. 1941 saw the beginnings of this.

Seems like the people at Messerschmitt didn't get the memo, when they made the Bf 109E carrying 250 kg (550 lb) bomb in 1940. Same with Macchi with 2x 160 kg bombs on the MC.200, despite the meagre power of the A.74. British fighters, with their bigger wings, should've carried even more, but the doctrine of fighter-bombers was in the same place with the doctrine of escort fighter - it was not there.
Regianne made fighter-bombers Re.2001 and 2002 capable for up to 630 kg bomb load, ie. around 500 lbs more than Blenheim. Under 1200 HP engines.

 

[Shortround6]

Seems like the people at Messerschmitt didn't get the memo, when they made the Bf 109E carrying 250 kg (550 lb) bomb in 1940. Same with Macchi with 2x 160 kg bombs on the MC.200, despite the meagre power of the A.74. British fighters, with their bigger wings, should've carried even more, but the doctrine of fighter-bombers was in the same place with the doctrine of escort fighter - it was not there.
Regianne made fighter-bombers Re.2001 and 2002 capable for up to 630 kg bomb load, ie. around 500 lbs more than Blenheim. Under 1200 HP engines.

A lot depends on the expected range of the aircraft and the missions.
A Blenheim is going to have over 3 times the radius of either 109 or Hurricane when carrying bombs.
If the enemy is close enough then the fighter bombers work.
The Re 2002 didn't show up until 1942 in production form?
sources vary. Some say the 2002 used a new 3 spar wing instead of the old 5 spar wing with integral fuel tanks.
One does wonder how big a runway the maximum load needed Supposedly one bomb under the fuselage and smaller bomb under each wing)

I wonder how much notice the world took of US Army and Navy fighters during the 1920s and early 1930s. Many of the biplanes could carry a single 500lb under tehfuselage or four 116lb bombs under the wing. But with under fuselage or under wing loads the fuel was restricted to around 50 gallons depending on model. Depending on model a 50 gallon axillary tank was carried under the fuselage.

 

[BlackSheep]

Hmm, a fighter bomber eh? That sounds like a Fairey Fulmar, Blackburn Skua, Douglas Dauntless maybe even a Brewster Buccaneer or even God forbid a Curtiss Helldiver. Did anyone here say it had to be a single seater? Sounds like a job for a two seat single engined fighter to me. Possibly even Potez 633, Whirlwind?

I'd say Dauntless. It wasn't a fighter but it wasn't exactly a sitting duck, either. When not dive bombing ships and point targets, it could still carry a decent bomb load for the time.
Ok, this came to mind while typing… where can we go by making a single-seat dauntless? Do we lose enough weight to make a real difference in range, payload, performance, and/or versatility?

 

[wlewisiii]

That would be interesting, but I think that in this timeframe the single biggest limitation is the engine availability. With a sufficiently larger engine, Douglas did just that: the AD-1 at the other end of the war.

 

[tomo pauk]

A lot depends on the expected range of the aircraft and the missions.
A Blenheim is going to have over 3 times the radius of either 109 or Hurricane when carrying bombs.
If the enemy is close enough then the fighter bombers work.

Fighter-bombers worked at shorter ranges. Nobody is trying to make a 500 mile radius fighter-bomber for the time frame specified.

The Re 2002 didn't show up until 1942 in production form?
sources vary. Some say the 2002 used a new 3 spar wing instead of the old 5 spar wing with integral fuel tanks.
One does wonder how big a runway the maximum load needed Supposedly one bomb under the fuselage and smaller bomb under each wing)

The big bomb was always under fuselage.
1100-1200 HP is always 1100-1200 HP, whether in 1939 or 1942.

 

[Admiral Beez]

Same drill as before: countries adopt a fighter-bomber idea a few years before it was wideaspread historically,

Does the Defiant have the makings of a fighter bomber? Rearward armament is excellent. Install a later, more powerful Merlin, bomb racks and underwing or in-wing cannons. Or a Skua/Roc combo? Skua's four gun wing with the Roc's four gun turret. We'll need a better engine.

 

[SaparotRob]

Realistic or not, I've always liked the Defiant and would have loved to seen it optimized somehow.

 

[Shortround6]

The Defiant worked well as a target tug.

It would be a lousy fighter bomber as the airframe sucked up hundreds of pounds holding up the turret and devoted to the turret itself at a true bomber type (or even fighter bomber) could devote to carrying bombs.

A Defiant MK 1 was around 1600-1700lbs heavier than a Hurricane using the same engine.

For the Roc to work with both turret and forward facing guns you need either a Sabre or an R-2800.

 

[SaparotRob]

I've read the threads about the Defiant. I know. It's such a nice looking aircraft, though.
The Roc should have been developed into landfill.

 

[Thumpalumpacus]

I abhor the idea of turret-fighters. I get that they were supposed to be bomber-destroyers, but the aim-the-plane approach developed in WWI was much more economical with weight, which obviously translates into improved performance.

 

[Admiral Beez]

Was there any single seat, single engined Japanese fighter that could have served as a fighter bomber? For starters we need floor, back and forward armour protection for the pilot, self sealing fuel tanks, cannon armament, and an ability to carry bombs.

 

[Shortround6]

Was there any single seat, single engined Japanese fighter that could have served as a fighter bomber? For starters we need floor, back and forward armour protection for the pilot, self sealing fuel tanks, cannon armament, and an ability to carry bombs.

Sure, just come up with the A-10 about 30 years early

The Ki-43 could hold a pair of 550lb bombs but there was only so much you were going to do with under 1200hp.
The P-40 didn't carry the amount of armor you want and didn't carry cannon.

The Typhoon meets your requirements but needs a 2000hp engine.

But very few fighter bombers met those requirements.

 

[GrauGeist]

Was there any single seat, single engined Japanese fighter that could have served as a fighter bomber? For starters we need floor, back and forward armour protection for the pilot, self sealing fuel tanks, cannon armament, and an ability to carry bombs.

With the exception of "floor armor", there was:
KI-84, N1K1-J, KI-61/KI-100

 

[Admiral Beez]

Sure, just come up with the A-10 about 30 years early

Some degree of armoured seat or floor shouldn't be impossible in 1940. Floor aside, many 1940-41 single engined fighters had armoured seat bases and backs and bullet resistant canopy fronts.