1939 Tactical Bomber

[Shortround6]

A lot of 'carrying capacity' had to do with field length. They hung a pair of 1000lb bombs off the P-40, same as Typhoon. What is hard to figure out is how long the runways were.
Or how far the P-40 could fly while carrying that weight. (less than full fuel?).

Doesn't do much good to design the best high speed tactical bomber in world if you only have two airfields it can take-off from and both of them are 500 miles away from the front lines.

In 1939/40 (production, design is several years old) you have to trade a lot of things off. Henley (and Fairey P.34/4) traded off a lot of "stuff" to get the performance they did.

The Fairey probably would NOT have gone into production with that canopy.
Low drag but doing tactical bombing with restricted vision is not a good idea, it was done, still not a good idea. Bomb load was supposed to be external.
The Henley

Looks like they had some renegade Frenchmen working in the design office.
Accounts differ, two 250lbs inside the fuselage bomb bay seems to be the most common. But the British are handicapped in history by the two-pitch prop, 87 octane fuel and and engine with a massive (for Summer of 1937) supercharger on the Merlin III. One machine gun in the wing, 94 Imp gallons of fuel.
I tend to doubt that Hawker put that large wing on the Henley just for laughs. They added 7ft 10 1/2 in to the wing span and about 84 sq ft. (32%) to the Hurricane.
Henley picked up about 28% in weight over a Hurricane I?

Now if you wait until 1936 instead of 1934 maybe things get a bit clearer. Different airfoil, different flaps? a supercharger more suited for low altitude work? 20-25% more power for take-off?
But in 1939/40 you still have no (or little) armor/protection, no better strafing than a Hawker Hind biplane and no better bomb load

four 112lb bombs. 104 Imp gallons of fuel. 348 sq ft of wing.

You are not going to get 1943/44 aircraft in 1939/40.
You want speed, forget heavy guns and heavy bomb load.
You want war load, forget speed and range.
every airplane is a comprise, what is the minimum you can accept in some categories?

two RCMGs or four? Beats the heck out of one.
500lb bomb load? or more? how many options (eight or twelve 20-25lb bombs?)
How is important is short field performance?
How important is vision?

Pilot had rather limited vision even with medium sized R-1830s. The successor lost a lot of speed for better vision.
deeper fuselage.

and some of that disappeared again when the larger R-2600s got large sand filters.

 

[ThomasP]

Maybe adapt the SNCASE/Sud Est SE.100 (aka LeO.50) or develop a similar design

Whether it could be put into service in time for the OP may be questionable in the real time line, but maybe in the alternate time line? First flight was march 1939.

Switch the high altitude rated engines for low(er) altitude rated variants.

"SNCASE SE.100 - Wikipedia"

 

[Shortround6]

What about the Bristol Beaufighter?

If the Hercules aren't ready, then use Merlins or the Wright R-2600.

Add extra forward armour for attacking ground targets, could swap the 4 x 20m for 2 x 40mm Vickers S Guns later in the war,

The Hercules was not "ready" in 1939 and barely ready in 1940.
You are running out of Merlins in 1940.
R-2600s are very iffy as to quantity.
163 built in 1939. They were ramping up quickly in in 1940.
July was the first time they went into triple digits, 168 engine instead of June's 96 and Dec finished the year with 351 engines. but 350 engines in Dec 1940 in Patterson NJ does the British no good for any part of 1940.


The whole tank busting thing needs a rethink in 1939/40. Too much retrospectroscope.
For the Germans, the Poles, Dutch and Belgians don't have enough tanks to worry about. Chances of a German tank busting aircraft actually finding a tank to shoot at is very, very, very low.
Chances of finding even a British tank in France in 1940 was pretty darn small, Low 300s?

The flip side is that while there were plenty of French tanks to shoot at (over 3000?) most of them were small

and had, for the time, heavy armor, about 30mm even on the sides and rear (40mm or more in the front) and pretty much beyond any 20mm to penetrate. Larger French tanks had even more armor.

The French and British (had they gotten the Hispano into production sooner) had a somewhat easier time of it as many German tanks only had 30mms on the front an often had 14-15mm armor on the rear and sometimes the sides (after upgrading from Poland).

Close support aircraft could do a lot more to defeat tanks by stripping way their artillery support and infantry support.

 

[nuuumannn]

I tend to doubt that Hawker put that large wing on the Henley just for laughs. They added 7ft 10 1/2 in to the wing span and about 84 sq ft. (32%) to the Hurricane.

The Henley's wing was dictated by its centre section, while maintaining commonality with Hurricane production by incorporating Hurricane wing outer panels. The difference was that in 1938 the Henley received metal covered wings while production Hurricanes kept their fabric covered wings until mid-late 1939. Likewise, the Henley was fitted with a de Havilland two-position prop in 1938 while the Hurricane still had a lump of wood up front until late 1939. The first Hurricane fitted with a constant speed prop was done so in February 1939, with production models rolling off the line in Autumn 1939.

I agree with everything you are saying SR, makes sense. At the time, the US Army had the same idea regarding attack airplanes in service, the Northrop A-17 was the primary attack aircraft of the USAAC and was the broad equal to the Fairey Battle and despite the latter being significantly bigger, it had better performance all round, no doubt helped by its more powerful engine. Army interest in the Douglas A-24 did not take place until 1940, but the first XBT, forerunner of the SBD Dauntless first flew in 1938. That would be my ground attack aircraft.

 

[Shortround6]

Maybe adapt the SNCASE/Sud Est SE.100 (aka LeO.50)

What happened to the rough/poor airfield requirement?

Super complicated nose/mainwheel (?) and the two rear wheels (main(?)/out riggers?) in the rudders attached to the Horizontal stabilizers?

Lets do 3-5 missions a day from muddy airfields

 

[Shortround6]

In 1938-39 a lot of the British airfields were 500yds to the Fence/trees. Things got better in a hurry in 1940 and later, But a service aircraft in 1939/early 1940 was designed for that limit.
They needed a certain take-off and landing speed. With poor propellers and rudimentary flaps one of the few tools left in the box of the aircraft designer was large wing area. by 1938-39 the designer had more tools in his box to handle short fields, but then the plane doesn't show up in service until late 1940 or 1941 or????

The Douglas BT needed a lot work.

The Navy might have lived with the large bulky landing gear, what they could NOT live with was the rather alarming tendency to flip over on it's back if it stalled while landing.

 

[ThomasP]

Hey Shortround6,

re "What happened to the rough/poor airfield requirement?"

I could be wrong, but I suspect the French designers knew the problem fairly well.

 

[nuuumannn]

The Douglas BT needed a lot work.

The Navy might have lived with the large bulky landing gear, what they could NOT live with was the rather alarming tendency to flip over on it's back if it stalled while landing.

That's the Northrop BT, not the Douglas XBT. The latter was a different aircraft. The Douglas XBT-2 was the true prototype of the SBD; it had inward retracting undercarriage and a raft of detail changes were made before it became the SBD-1, although the first of these was not completed until 1940.

 

[yulzari]

In 1938-39 a lot of the British airfields were 500yds to the Fence/trees. Things got better in a hurry in 1940 and later, But a service aircraft in 1939/early 1940 was designed for that limit.
They needed a certain take-off and landing speed. With poor propellers and rudimentary flaps one of the few tools left in the box of the aircraft designer was large wing area. by 1938-39 the designer had more tools in his box to handle short fields, but then the plane doesn't show up in service until late 1940 or 1941 or????

Also the expected operations were expected to be from France not UK bases. The UK bases were being progressively improved but the bases being given to the RAF in France were more WW1 than WW2. Yes the French had several good quality all weather reasonably long runway bases but these were for the French air force. The strategic Fairey Battle force got the next best but the rest got short muddy fields with the hedgerows removed. All right for the Lysanders even with the full bomb load of 500lb and the Gladiators but it limited the carriage and fuel of the tactical Battles and Hurricanes and Blenheims. With the power available at the time, whatever might have come soon,and the propellers in use fixed pitch Gladiators and Hurricanes and 2 position Battles and Lysanders. There was no equivalent giant civil engineering programme in France to that ever growing one in Britain that eventually led to huge patches of concrete every few miles across much of the countryside. What you design for the period has to be able to take off from a small muddy field in a crosswind with a possibly fixed propellor and as much power as was actually available on 87 octane fuel.

Take the Hurricane as an example. In 1942 you can count on 300 odd extra horsepower at least, just maybe 600, plus a constant speed propellor to drag you off the much longer better drained or concrete runway in Britain so can carry up to 1,000lb of bombs etc. with full ammunition for 4x20mm cannon and full tanks. The BoF Hurricane is hard put to drag itself off a muddy field with nothing hanging off it pulled by a bent wooden stick. There was a good reason why the Hawker Henley had 1/3 extra wing area to do the task later better done with a standard MkIV Hurricane.

Tangentially the Royal Navy answer to their equivalent problem was wing area hence the choice of a biplane layout for the new Fairey Albacores with a 2,000lb bomb load, torpedo or mine and the advantage of being able to turn into the wind and ordering the oars to ramming speed. For the follow up more powerful engines they felt that they could get away with a monoplane with less wing area from the same decks.

 

[Shortround6]

That's the Northrop BT, not the Douglas XBT. The latter was a different aircraft. The Douglas XBT-2 was the true prototype of the SBD; it had inward retracting undercarriage and a raft of detail changes were made before it became the SBD-1, although the first of these was not completed until 1940.

Northrop had been bought out by Douglas. With the change in ownership came a change in management and design team.
Jack Northrop was off to design flying wings and things like the P-61 and later the F-89. Some of the Northrop designs continued production under old designations.
The Northrop A-17/A-17A and Douglas A-33 is such a chain. Fixed landing gear A-17s are Northrop. Retracting landing gear A-17A's were ordered from Northrop, delivered by Douglas and the larger engined A-33s pretty much all Douglas.

Extreme nit-picking aside, the 1930s were a period of extreme evolution in both aerodynamics ( streamlining and control) and structure. Just because a company, or several, could do something in 1941 does not mean that most (any?) companies could do it 1938.
The Northrop BT-1 was sort of a small wing (3 ft or so taken out of the middle, not clipped off the ends) A-17 with that funky landing gear instead of the rearward landing gear used on the SBD and A-17A.

 

[GrauGeist]

Messerschmitt did have the Bf162 available in 1937, which could have been modified according to need.

But then again, the Ju88 was available by 1937 (which is why the Bf162 was not further developed).

 

[special ed]

What happened to the rough/poor airfield requirement?
View attachment 764733
Super complicated nose/mainwheel (?) and the two rear wheels (main(?)/out riggers?) in the rudders attached to the Horizontal stabilizers?
View attachment 764734

Lets do 3-5 missions a day from muddy airfields

Looking at the retracting outrigger wheels, a grass field without mud would interfere with operation and require cleaning often.

 

[ThomasP]

Quite possibly, but if that was too much of a problem they could probably lock them down as the British did on the Hurricane and Spitfire, and effectively close up the wells in one way or another. It would cost them a few mph in Vmax but IMO it would not affect the ability to perform the job per the OP.

A possible bit of interest. When I first looked at the pictures of the SE.100 I did not think about the size, but that is a big airframe. When I did my best to scale the tail wheels on the SE.100 they come out to about the same size as the main landing gear wheels on the Hurricane.

 

[z42]

Interesting thread. A few more or less uninformed opinions.

• It seems the experience throughout the war of unescorted bombers vs fighters, the fighters were able to inflict unsustainable casualty rates on the bombers. Hence the requirement to fend for itself IMHO implies either a bomber that is as fast as single engined fighters (Mosquito-like, but in 1939?), or then a fighter-bomber able to function as a more or less full-blooded fighter after jettisoning the ground ordnance.
• AFAIU the motivation behind (near) vertical dive bombing was accuracy. If we're giving up on this approach, we need something else that can give decent accuracy. I think the low angle bomb sights weren't really a thing until mid-late war?
• As for shooting tanks, in the end there aren't that many of them around, particularly in the early war years. Not convinced the approaches mounting 37/40mm AT guns on aircraft were that successful, all things considering. Later in the war one gets access to rockets anyway, which to some extent can replace these large guns.

 

[wuzak]

Interesting thread. A few more or less uninformed opinions.

• It seems the experience throughout the war of unescorted bombers vs fighters, the fighters were able to inflict unsustainable casualty rates on the bombers. Hence the requirement to fend for itself IMHO implies either a bomber that is as fast as single engined fighters (Mosquito-like, but in 1939?), or then a fighter-bomber able to function as a more or less full-blooded fighter after jettisoning the ground ordnance.
• AFAIU the motivation behind (near) vertical dive bombing was accuracy. If we're giving up on this approach, we need something else that can give decent accuracy. I think the low angle bomb sights weren't really a thing until mid-late war?
• As for shooting tanks, in the end there aren't that many of them around, particularly in the early war years. Not convinced the approaches mounting 37/40mm AT guns on aircraft were that successful, all things considering. Later in the war one gets access to rockets anyway, which to some extent can replace these large guns.

Weren't rockets notoriously inaccurate?

Big guns were more accurate, but required the attacking aircraft to get closer?

Was near vertical dive bombing almost suicidal in well defended areas?

 

[Shortround6]

There is only so much you can do with 1000-1100hp engines. The bombers will be slower. They do not have to be as fast as the fighters exactly. A fighter that is 10-12mph faster is going to need abut 5 minutes to close a one mile gap. How much slower is a question. What is enclosed bomb-bay worth, or the radio operator/rear gunner or other feature/s?
Again what is the desired field performance?
You may be able to build a fast bomber, but it won't climb. Climb is a lot more power to weight than power vs drag. If it was easy everybody would have done it

Dive bombing requires an attack from 10-12,000ft. What can you see from 10-12,000ft? At 240mph a dive bomber will loose over 10,000ft of altitude in 30 seconds. So the pilot has well under to 30 seconds after he stabilizes the plane in the dive, and allows for the several thousand feet of pull out. That is his time to "aim" the plane/bomb.

Going to low level attack reduces the risk of ground fire/AA but the accuracy goes to pot. Now this depends on the target and the type of attack. The mid 30s A-17s carried twenty 30lb bombs in internal bays/chutes that would be good for bombing supply columns, unentrenched infantry, unentrenched artillery, etc.
US Attack bombers (not saying they were right, just that this is what they used) for all of the 1930s used four .30 cal machineguns for strafing. And for the 30s that was twice the firepower of a US fighter. It was double that of the Ju-87 and the Lysander and 4 times the firepower of the Henley.

Which brings us to anti-tank thing in 1939-40. As z42 has stated there weren't that many tanks and as I have pointed out, the Germans didn't have a gun that would work against most of the French tanks. The French and British had the 20mm Hispano but it was rather borderline, despite British hopes in Sept 1940. The Germans had up armored many of their tanks between 1939 and the summer of 1940 and while there were still weak points on the older ones, the newer ones had 30mm armor which offered very strong protection against 20mm Hispano fire. Now installing twin 20mm cannon was going to cut performance on most planes that had 900-1100hp engines unless you built twin engined planes.

 

[z42]

Weren't rockets notoriously inaccurate?

Big guns were more accurate, but required the attacking aircraft to get closer?

Was near vertical dive bombing almost suicidal in well defended areas?

Less inaccurate than low level bombing, presumably, otherwise why would they have bothered with the rockets?

Big guns might be more accurate, but with low rpm there weren't that many chances to score a hit in a attack run. Maybe better to have high rpm guns and chew up unarmored targets instead? Shoot up the fuel trucks and the tanks will stop soon enough.

 

[PStickney]

DB-7?

Martin 167 as a backup.

 

[Howard Gibson]

We missed an interesting aircraft, the Leo 45 from France. This did around 300mph with 900hp Gnome Rhone 14N engine with 920HP. They were planning on 1300HP engines later, and eventually, they installled Pratt & Whitney R-1803s with 1200HP. The original aircraft did 227mph at sea level, and 298mph at 15,700ft, and there were over 200 in service in May 1940.

This was a relatively large aircraft, around the size of a B-25 Mitchell or B-26 Marauder. During the Blitzkrieg, they suffered from a lack of air superority.

 

[yulzari]

We missed an interesting aircraft, the Leo 45 from France. This did around 300mph with 900hp Gnome Rhone 14N engine with 920HP. They were planning on 1300HP engines later, and eventually, they installled Pratt & Whitney R-1803s with 1200HP. The original aircraft did 227mph at sea level, and 298mph at 15,700ft, and there were over 200 in service in May 1940.

This was a relatively large aircraft, around the size of a B-25 Mitchell or B-26 Marauder. During the Blitzkrieg, they suffered from a lack of air superority.

Used in bombing Gibraltar, against Commonwealth forces in Syria and allied forces in Algeria.