Advanced French Fighters vs 1942/1943 contemporaries (8 Viewers)

[Steamed_Banana]

What effect if any did wind tunnel work with the engines have on the 12Y or 14N development?

 

[Bretoal2]

Superchargers have to do two things.
1. Multiple the starting air pressure to the desired manifold pressure.
2. Flow enough mass of air (pounds or Kg of air) to make the power desired.

Compressing 760mm pressure to 880mm at sea level is not hard. It is higher up that gets hard.
meters altitude.................starting pressure.................desired pressure.......................multiplication needed.
0....................................................760............................................880.....................................................1.158
2300............................................574.4.........................................880.....................................................1.532
3260............................................506.7.........................................880.....................................................1.737
4200...........................................450.4..........................................880.....................................................1.954
6000...........................................353.9..........................................880.....................................................2.486
Merlin III
4950...........................................407.9........................................1057....................................................2.591

Yes, that is exactly right.

Specifically regarding the 12Z 17, the power curves I provided in post #678 show that a manifold pressure of 140 to 143.5 *pièzes* - a rather peculiar unit of pressure that enjoyed a brief period of prominence in France during the 1940s, one being equivalent to 7.50 mm Hg - could be maintained up to an altitude of 5,850 to 5,900 meters.

I.e. a manifold pressure of 1075 mm Hg at an altitude where the local pressure is 359 mm Hg. The supercharger multiplication factor is therefore 1075/359 = 2.99—nearly 3.

Not too bad....

 

[Shortround6]

D.520s and H-75s and Leo 451s and DB-7s flying 2-3 months after they arrive from the factories are going to have much better outcomes than those thrown into the breach within days of their being taken out of the crates.

It is one thing to take planes out of crates and give them to units that have been flying the same planes for 2-4 months. They know what to look for and how the plane should handle. Giving them to experienced air and ground crews with experience on other types is going to need a learning curve. Giving them to new units with only a sprinkling of experienced pilots and mechanics is not going to go well.

Bombing cities is / was militarily pointless, for the most part

That is very, very true. However, that is not what was believed by the bombing adherents of the 1920s and much of 1930s. It was believed in many air forces that aerial bombardment alone would force an enemy to surrender or face rioting in the streets or uprisings toppling the government. They also believed they only needed a few hundred bombers to do it and those bombers didn't need 2-4000kg payloads. It was supposed to be a "cheap" way of projecting power and waging war compared to tens or hundreds of thousands men on the ground. It took a few years for the militarily pointless to sink in, even for the British after suffering through blitz. Germans would not have the fortitude of the British civilians and just one (or two) more destroyed cities would tip the balance. (sarcasm)

Leo 451 was just a better bomber based on a newer design. I think by say, summer of 1940 the French have better capacity to bomb German strategic targets than vice versa, partly due to bombers available (including Martin 167 and DB-7 as well as Leo 451 and Amoit 35X),

The He 111 was not that bad a design. Clever design only buys so much and depending on clever design to offset 20% bigger airplane is asking for a lot.
He 111 and Ju 86 were started in 1934. He 111 started with 750hp unsupercharged BMW engines and was pretty much a failure, Switching to 950hp DB 600 engines (carburetors) and superchargers fixed most of the problems in 1936.
LeO 451 and Amoit 350 started in a 1934 program and in typical French fashion it took a while to produce results (too much dicking around with the specifications) and prototypes didn't fly until early 1937.
The LeO 451 and Amoit 350 weren't that much more advanced than the He 111, they were way ahead of the Ju-86 though.
Trying to do 1939-40-41 strategic bombing with roughly 1000kg payloads was not going to actually work despite what "theory" said.
And that cuts out the smaller plane/s leaving the LeO 451 and it has problems with bomb capacity vs fuel load although better engines could probably fix that.
French were working on 4 engine heavy bombers to replace the Farmans

but they were too late although the first allied bomber to bomb Berlin was a relative.

A single plane attacked Berlin on the night of June 7th and returned.

 

[Steamed_Banana]

It is one thing to take planes out of crates and give them to units that have been flying the same planes for 2-4 months. They know what to look for and how the plane should handle. Giving them to experienced air and ground crews with experience on other types is going to need a learning curve. Giving them to new units with only a sprinkling of experienced pilots and mechanics is not going to go well.

That is very, very true. However, that is not what was believed by the bombing adherents of the 1920s and much of 1930s. It was believed in many air forces that aerial bombardment alone would force an enemy to surrender or face rioting in the streets or uprisings toppling the government. They also believed they only needed a few hundred bombers to do it and those bombers didn't need 2-4000kg payloads. It was supposed to be a "cheap" way of projecting power and waging war compared to tens or hundreds of thousands men on the ground. It took a few years for the militarily pointless to sink in, even for the British after suffering through blitz. Germans would not have the fortitude of the British civilians and just one (or two) more destroyed cities would tip the balance.

The He 111 was not that bad a design. Clever design only buys so much and depending on clever design to offset 20% bigger airplane is asking for a lot.
He 111 and Ju 86 were started in 1934. He 111 started with 750hp unsupercharged BMW engines and was pretty much a failure, Switching to 950hp DB 600 engines (carburetors) and superchargers fixed most of the problems in 1936.
LeO 451 and Amoit 350 started in a 1934 program and in typical French fashion it took a while to produce results (too much dicking around with the specifications) and prototypes didn't fly until early 1937.
The LeO 451 and Amoit 350 weren't that much more advanced than the He 111, they were way ahead of the Ju-86 though.

If you look at an LeO 451 and an He 111 in the same scale, the He 111 is much thicker / fatter. It was originally designed as a dual use bomber / airliner / transport. It's shaped like a carp or a fat cigar. And the dorsal and ventral gun positions stick out more. The wings are a good bit thicker too.

Wing span is roughly the same but wing area on the He 111 is 87 m2 (943 sq ft) vs 68 m2 (732 sq ft) on the LeO 451.

I don't know what the exact wing thickness is but you can see from the three view plans here it's much thicker on the He 111

By comparison, the LeO 451 fuselage is much thinner in profile, it's almost comparable to an A-20A or Boston III.

That extra thickness translates to drag, which is why top speed for the He 111 goes from 111E at 242 mph / 390 kph to 111H at 254-270 mph (400-435 kph) while the LeO 451 made 308 mph (500 kph)

Cruising speed was 186-230 mph for the He 111 (loaded / light) vs 224 - 260 mph / 360-420 kph for the LeO 451

He 111 could theoretically carry more bombs (2,000 kg vs 1,500 kg typically) but the vertical bomb bay cells limit bomb sizes.

LeO 451 also has better range of 2,300 km with a bomb load vs 1,200 km for the He 111.

Trying to do 1939-40-41 strategic bombing with roughly 1000kg payloads was not going to actually work despite what "theory" said.

That depends a lot on A) what you consider a strategic target B) how accurate your bombing is and C) the specific nature of the target (is it hardened etc.)

And that cuts out the smaller plane/s leaving the LeO 451 and it has problems with bomb capacity vs fuel load although better engines could probably fix that.

I don't think the LeO 451 actually has any problems with bomb load vs fuel load. And don't forget the Amoit 351.

Now the US types, Boston and Maryland, do have a relatively small bomb load, but both proved effective in the Western Desert in British hands against Tactical and Operational targets.

If you can cut rail lines and bridges leading to the factories that's almost as good as knocking out the factories themselves.

French were working on 4 engine heavy bombers to replace the Farmans
View attachment 899530
but they were too late although the first allied bomber to bomb Berlin was a relative.
View attachment 899531
A single plane attacked Berlin on the night of June 7th and returned.

I really need to make a model of one of those hideous Farman. I don't think the French needed any four engine bombers TBH. Four engine aircraft were good for maritime patrol but probably not ideal for bombing.