The Germans needed a better tactical bomber in 1942 (1 Viewer)

[pbehn]

A de Havilland Mosquito BXVI had an empty weight of 14,600lb and a maximum weight of 23,000lb. Presumably, this could include a 4,000lb "cookie". A Boeing 737 has an empty weight of 65,300lb. What was the bomb load?

A poster here who was a civilian airline pilot said that todays large wide bodied jets can be trimmed to be slightly tail heavy on climb so the plane climbs "cleaner" saving fuel compared to using the elevators. When flying to Japan one time we were invited into the cockpit (how times change, that was 1986) the pilot said that the weight of the passengers in a 747 was such a small fraction of the total weight of plane fuel and cargo that it made no difference what the passengers did, it didnt affect the plane in flight.

 

[tomo pauk]

One of the more interesting suggestions for a fast bomber (a thing that a tactical bomber should be, too) was the future Ta 211 paper project, that was developed into a real - if stillborn - Ta 154. Tail-dragger (IMO, the benefit is that it does not dictate that fuselage volume is dedicated to it - a good thing on a small aircraft), two Jumo 211 engines, mid-wing with 1 crew member, half-decent bomb bay, fixed rear-firing guns, pilot has a periscope.
A notable thing about it that can be read in the 'Secret projects of the LW' bookazine by Dan Sharp was the very small wing - just 25 sqm - in-between the Whirlwind and the Ro.58. Expected top speed was to be 650 km/h.
As a tactical bomber, we'd probably prefer that some fuel just behind the pilot is replaced by forward guns.

 

[Steamed_Banana]

What do you think of LeO 451 and an option? Has the benefit of being around early. And apparently the French factory was really cranking them out... what is one of those like with a pair of Jumo 211s?

 

[tomo pauk]

What do you think of LeO 451 and an option? Has the benefit of being around early. And apparently the French factory was really cranking them out... what is one of those like with a pair of Jumo 211s?

As a tactical bomber?

 

[Steamed_Banana]

As a tactical bomber?

As perhaps the tactical / operational side of a pair of useful assets including Fw 190G, which doesn't really seem to have any special vices that I'm aware of for either 'tactical operational bomber' escort or longish range fighter-bomber roles.

But I see these both as useful in the daylight bombing role, like say in 1943 in North Africa and the Med. Which may or may not be viable.

But if you had these carrying torpedoes and Fw 190G escorts (and / or Fw 190G fighter bombers), I don't think Pedastal makes it to Malta. Malta might fall. Allied efforts in North Africa get a lot more difficult. US is going to get a more thorough bashing after Torch. Axis might rally against Monty in Egypt / Libya. Allied supply chains across the Med may be seriously threatened.

Some of this scenario would depend on how much faster you can make an LeO 451 go than it's 1940 version. That's already good for 1940 but we need at least 350 mph by 1942, preferably into the 375 mph range. I have model kits of one of these and a Ju 88, Martin 167 and 187, A-20 and some others behind me on the shelf. LeO is slightly bigger than a Ju 88 but has a slim fuselage, maybe a little slimmer than an A-20. Maybe the wing doesn't need to be quite that big (which might trade speed for range and altitude capability). It has that ridiculously huge gun on the dorsal position (admittedly half of the reason I bought the kit and made it) which could be replaced with something more streamlined and effective (more ammunition capacity) though I'd keep a 20mm there. And it has that silly ventral tub thing which needs to be removed (I think the French did remove these for service after the BoF)

Most importantly, even with 1,000 hp Gnome Rhone engines, this thing makes 300 mph in 1940, carries a big bomb load, has a long range, and apparently handles well.

What happens if you put Jumo 211 or BMW 801 in it, . How fast does it get to. Speed - both sprint speed and cruising speed- would help determine what it might used or useful for long term.

 

[Steamed_Banana]

Since 1943 is mentioned in the first post...
This is the year of the first flights of the Do 335 and Ar 234. Aren't they the best tactical LW bombers for what-if 1944-1945?
I'm not sure whether the Do 335's development could be sped up, or whether such problems as overheating, vibration, and pilot ejection safety could be resolved at all.
However, Ar 234's history could be different if:
- Arado concentrates first and mostly on this model, dropping the "dead ends", such as Ar 240/440.
- Conventional landing gear from the outset, probably, would save half a year at least.
- RLM already in 1941 foresaw the deficit of nickel and chromium (required for Jumo 004A blades), prioritised Jumo 004B, directed the required resources accordingly, and Junkers started to work on the hollow blades. Another year saved?
- Decision makers such as Milch were less sceptical about jet technology.
Even in real life, Ar 234, arguably, was the best tactical bomber of its period. What if production/deployment/training began 1.5 years earlier and en masse?

I never really understood why the Ar 234 didn't fully work out, I guess i assumed it's due to flakiness of the jet engines? Does anyone have a good summary? Can they get the jets to work reliably in early-ish 1943? If so it looks like a fantastic option. They were used, I gather, somewhat in post Ardennes offensive air strikes with some efficacy

 

[Steamed_Banana]

Leo 451 and Fw 190 even have a kind of apparent 'family resemblance' lol

 

[Dogwalker]

I never really understood why the Ar 234 didn't fully work out, I guess i assumed it's due to flakiness of the jet engines? Does anyone have a good summary? Can they get the jets to work reliably in early-ish 1943? If so it looks like a fantastic option. They were used, I gather, somewhat in post Ardennes offensive air strikes with some efficacy

Speed was it's only defense, but, being designed for reconnaissance, it didn't have an internal bomb bay (fuselage was occupied by fuel). Bomb load of the bomber variant was carried on three external hardpoints and, being the aircraft also quite aerodynamic, every bomb degraded performances by quite much. Max speed with the central bomb was already about 50km/h inferior than in clean configuration. With three bombs it was likely slower than a loaded Mosquito, and it had to operate on heavily hostile skies.

 

[Howard Gibson]

I never really understood why the Ar 234 didn't fully work out, I guess i assumed it's due to flakiness of the jet engines? Does anyone have a good summary? Can they get the jets to work reliably in early-ish 1943? If so it looks like a fantastic option. They were used, I gather, somewhat in post Ardennes offensive air strikes with some efficacy

Was the Ar234 a failure? There were not very many of them, and it was late in the war. The problem with the engines is that the Germans lacked the alloy material to create heat resistant turbines. The missions may have been tactically successful, but strategically, they were irrelevant.

In mid-1944, the Luftwaffe had about ninety He177s deployed on the Russian Front. They conducted daylight raids against tactical depots and such, and their casualties were low. This did nothing to deter or prevent Operation Bagration. The Russians were not even forced to take advantage of the Spitfire_IXs they were supplied on Lend Lease. Once again, not enough aircraft, too late in the war.

 

[Steamed_Banana]

Too little / too late (or just 'too late') is often the big problem. This also applies to many famous Allied aircraft variants.

 

[Steamed_Banana]

Was the Ar234 a failure? There were not very many of them, and it was late in the war. The problem with the engines is that the Germans lacked the alloy material to create heat resistant turbines. The missions may have been tactically successful, but strategically, they were irrelevant.

Was the metal alloy issue something that manifested late in the war or was it a problem all along?

I know there were a few epic transfers between Germany and Japan of rare metals etc. by submarine, which worked initially and then failed several times. Somewhere some day a brilliant treasure hunter will find a wrecked submarine full of tungsten and irridium and gold bars and secret blueprints and all kinds of other treasures.

Japanese submarine I-52 (1942) - Wikipedia

en.wikipedia.org

Japanese submarine I-34 - Wikipedia

en.wikipedia.org

In mid-1944, the Luftwaffe had about ninety He177s deployed on the Russian Front. They conducted daylight raids against tactical depots and such, and their casualties were low. This did nothing to deter or prevent Operation Bagration. The Russians were not even forced to take advantage of the Spitfire_IXs they were supplied on Lend Lease. Once again, not enough aircraft, too late in the war.

Something like an LeO 451 could have been available in much larger numbers and might have been almost invulnerable over the Soviet Union...

 

[tomo pauk]

Some of this scenario would depend on how much faster you can make an LeO 451 go than it's 1940 version. That's already good for 1940 but we need at least 350 mph by 1942, preferably into the 375 mph range. I have model kits of one of these and a Ju 88, Martin 167 and 187, A-20 and some others behind me on the shelf. LeO is slightly bigger than a Ju 88 but has a slim fuselage, maybe a little slimmer than an A-20. Maybe the wing doesn't need to be quite that big (which might trade speed for range and altitude capability). It has that ridiculously huge gun on the dorsal position (admittedly half of the reason I bought the kit and made it) which could be replaced with something more streamlined and effective (more ammunition capacity) though I'd keep a 20mm there. And it has that silly ventral tub thing which needs to be removed (I think the French did remove these for service after the BoF)

A few questions that I'd try to answer before coming to the half-decent conclusion. Like:
- What sort of speed is required - 350 mph will be workable in Russia, Med will indeed need 360+ mph in order the Spitfire Vs are less of a threat, close to 400 if immunity vs. Typhoon is required (that is against the UK).
- What engines are available, and how good might they be? BMW 801 is probably the best bet, after it the DB 601E/605A, with Jumo 211s being the 3rd tier. DB 603A is the best for 1943 in theory, but it was badly unreliable before Spring of 1944.
- What kind of a design can give 360+ mph? A very small aircraft powered with the Jumos, a bigger A/C powered by the DBs, a still bigger A/C if BMWs are aboard?
- Where that puts the LeO 451? It was a sizable aircraft, bigger than the A-26 for example. The A-26, with it's laminar-flow wing and R-2800s, did 360 mph. The Tu-2S did ~330 mph with engines comparable to the BMW 801, it was a smaller aircraft that the 451. The P1Y did 340 mph with the Homares.

My tl;dr from all of this is that the Leo451 will be lucky to hit 350 mph even if powered by the fully-rated BMW 801D engines. However, that turn of speed puts it into a far better spot than the Ju 88.

 

[Shortround6]

Most importantly, even with 1,000 hp Gnome Rhone engines, this thing makes 300 mph in 1940, carries a big bomb load, has a long range, and apparently handles well.

What happens if you put Jumo 211 or BMW 801 in it, . How fast does it get to. Speed - both sprint speed and cruising speed- would help determine what it might used or useful for long term.

A rough estimate of power needed is to use cube root of the power used to fly at the known speed. Wiki claims 1060hp for the engines in the LeO 451, but this is power at altitude.
1060=10.19
Then figure out how much faster you want to go
300mph x 1.083 = 325mph
300mph x 1.166 = 350mph
The multiple the 10.19 times the speed increase.
10.19 x 1.083 = 11.04
10.19 x 1.166 = 11.88
The cube the resulting number
11.04 x 11.04 x 11.04 = 1345hp
11.88 x 11.88 x 11.88 = 1676hp

Two problems.
1. We are assuming the co-efficient of drag stays the same as we push into the 300mph speed range. It doesn't, It is pretty good in the low 300s. In the mid 300s in starts getting squirrely. People who are better at aerodynamics than I am can explain more if they wish.
2. This is roughly accurate if the weight and drag of the airplane stays the same. Adding several thousand pounds of weight will change the induced drag at least some and changes to shape (engine nacelles and cooling) are usually going to require more power.
What is power at 15-16,000ft of the engines that you want to use?
BMW 801 used in the Do 217E was good for 1380hp at 15,100ft?

 

[Elan Vital]

For reference the max speed of a production LeO 451 was to be at least 465 kph (289 mph) at 4800m, usually it was between 485 and 495 kph (301-307 mph) in general.

The LeO 455 which was then credited with a power output of 1250 hp at 5000m was estimated to achieve 520 kph (323 mph) at that altitude. The prototype achieved 503 kph but that was with very little flying time so it was both more optimal (prototype) but also less optimal (no fine tuning of the prototype to achieve its full potential) than a production 455 would have been.

The structural redesign developped by the SNCAO to facilitate production would also have saved some weight, but IMO even with very powerful German engines and more streamlined armament you'd need some fundamental changes to the aircraft's shape to get the required speeds.

 

[tomo pauk]

A rough estimate of power needed is to use cube root of the power used to fly at the known speed. Wiki claims 1060hp for the engines in the LeO 451, but this is power at altitude.
1060=10.19
Then figure out how much faster you want to go
300mph x 1.083 = 325mph
300mph x 1.166 = 350mph
The multiple the 10.19 times the speed increase.
10.19 x 1.083 = 11.04
10.19 x 1.166 = 11.88
The cube the resulting number
11.04 x 11.04 x 11.04 = 1345hp
11.88 x 11.88 x 11.88 = 1676hp

What is power at 15-16,000ft of the engines that you want to use?

The closest to the power required to make 350 mph seems to be either the DB 603A (assuming it does not catastrophically disassemble mid-air) and the over-boosted BMW 801D (granted these was achieved by some time in second half of 1943 - doc is from November - and not in 1942).
BTW - how good/bad were the exhausts on the LeO 451?

 

[Steamed_Banana]

Already the LeO 451 even with 1250 hp looks significantly superior to the Ju 88 in terms of performance (although the 455 was specifically a high altitude variant, which isn't necessarily what we want here). If you replace the giant Hispano with an MG FF or MG 151/20 you'll have superior defensive armament too.

The French were producing 4-5 of these aircraft per day in 1940 before the armistice.

English Wikipedia says it carried 7 x 200 kg bombs 'in the belly' and two 'in the wings'. Does this mean it had bomb bays in the engine nacelles? Maybe those would be better used for fuel.

If this means that 7 x 200 kg bombs (or even 5) could be carried fully within internal bomb-bays, then it really has a leg up on the Ju 88.

French Wikipedia says they had some challenges with takeoff and landing and some manufacturing defects, but that is to be expected with early production type under rushed production during wartime. Presumably that could have been worked out by 1942. Maybe they need slightly larger rudders etc.

Apparently Free French converted some of their LeO 451 to use P&W R-1830 engines (these were called LeO 453) and they were experimenting with using R-2600 or Bristol Hercules, though this never went far.

By the way, another promising French candidate for this would be the Amiot 351 / 354 which looks a lot like the LeO 451 and had similar dimensions and performance, but was deemed easier handling and of better manufacture by the French air force in 1940.

 

[Steamed_Banana]

As for size, here is my crappy model of a LeO 451 next to similarly crappy models of Tupolev Tu-2, Douglas A-20, and Martin 187 Baltimore.

As you can see, LeO 451 of course has a much wider wingspan (73' vs 62' on Tu-2 and 61' 4" on Martin 187 and A-20), and it's a bit longer (56' 4" vs 45' 3", 48', and 48' 6" respectively), but overall fuselage size and shape, and engine nacelles etc. size are very similar. Presumably you could clip the wings a bit though i don't know if that is as easy or trouble free as on a fighter.

It's much slimmer than a B-26 though I don't have one of those to compare it with.

 

[Dimlee]

I never really understood why the Ar 234 didn't fully work out, I guess i assumed it's due to flakiness of the jet engines? Does anyone have a good summary? Can they get the jets to work reliably in early-ish 1943? If so it looks like a fantastic option. They were used, I gather, somewhat in post Ardennes offensive air strikes with some efficacy

In my opinion, Ar 234 were successful, but of course could not change the big picture. I agree with Howard Gibson on that.
This book should be interesting. It was on my "to read" list for a couple of years; I hope to find time to read it.

Amazon.com: Arado Ar 234 Bomber and Reconnaissance Units (Combat Aircraft Book 134) eBook : Forsyth, Robert, Beale, Nick, Swiatlon, Janusz, Postlethwaite, Mark: Kindle Store

Amazon.com: Arado Ar 234 Bomber and Reconnaissance Units (Combat Aircraft Book 134) eBook : Forsyth, Robert, Beale, Nick, Swiatlon, Janusz, Postlethwaite, Mark: Kindle Store

www.amazon.com

There was a good work by Russian authors Dyogtev and Zubov. Probably never translated, unfortunately.

Ar-234 «ÐлиÑ». РеакÑивнÑй ÑÐµÐ½Ð¸ÐºÑ Ð»ÑÑÑваÑÑе by ÐмиÑÑий ÐÑгÑев, ÐмиÑÑий ÐÑбов - Books on Google Play

Ar-234 «ÐлиÑ». РеакÑивнÑй ÑÐµÐ½Ð¸ÐºÑ Ð»ÑÑÑваÑÑе - Ebook written by ÐмиÑÑий ÐÑгÑев, ÐмиÑÑий ÐÑбов. Read this book using Google Play Books app on your PC, android, iOS devices. Download for offline reading, highlight, bookmark or take notes while you read Ar-234...

play.google.com

 

[Shortround6]

Already the LeO 451 even with 1250 hp looks significantly superior to the Ju 88 in terms of performance (although the 455 was specifically a high altitude variant, which isn't necessarily what we want here). If you replace the giant Hispano with an MG FF or MG 151/20 you'll have superior defensive armament too.

The French were producing 4-5 of these aircraft per day in 1940 before the armistice.

English Wikipedia says it carried 7 x 200 kg bombs 'in the belly' and two 'in the wings'. Does this mean it had bomb bays in the engine nacelles? Maybe those would be better used for fuel.

If this means that 7 x 200 kg bombs (or even 5) could be carried fully within internal bomb-bays, then it really has a leg up on the Ju 88.

French Wikipedia says they had some challenges with takeoff and landing and some manufacturing defects, but that is to be expected with early production type under rushed production during wartime. Presumably that could have been worked out by 1942. Maybe they need slightly larger rudders etc.

Apparently Free French converted some of their LeO 451 to use P&W R-1830 engines (these were called LeO 453) and they were experimenting with using R-2600 or Bristol Hercules, though this never went far.

By the way, another promising French candidate for this would be the Amiot 351 / 354 which looks a lot like the LeO 451 and had similar dimensions and performance, but was deemed easier handling and of better manufacture by the French air force in 1940.

View attachment 872005

View attachment 872006

One description of the LeO 451 has a bomb cell in each wing root, like some British bombers (?).
But much like the Ju 88, large bomb load meant not much fuel. Perhaps a more powerful engine could allow a higher gross weight?
No idea if gross weight was a structural problem or a field length problem.
The Long gun may not be as much problem as you think as the mount was supposed to be powered, I don't know if in direction or two directions.
Changing the drum required courage
Swapping for the MG FF might be going backward. You still have the drum problem, The MG FF is slower firing (at least some) and using lower velocity shells means you have to lead targets more. Hopefully the powered mount makes it easier to aim than a manual 20mm gun.
Getting a belt feed like the MG 151 would be a considerable improvement.
Also an improvement would be some sort of ventral blister mount behind the bombbay for a twin 7.5-8mm machine gun or a single 13mm gun. Less drag than the French mount and double the firepower.

 

[Howard Gibson]

Was the metal alloy issue something that manifested late in the war or was it a problem all along?

I assume the lack of high temperature alloys kept the Germans from building turbines and turbochargers. Not important early in the war.

I know there were a few epic transfers between Germany and Japan of rare metals etc. by submarine, which worked initially and then failed several times. Somewhere some day a brilliant treasure hunter will find a wrecked submarine full of tungsten and irridium and gold bars and secret blueprints and all kinds of other treasures.

Japanese submarine I-52 (1942) - Wikipedia

en.wikipedia.org

Japanese submarine I-34 - Wikipedia

en.wikipedia.org

Something like an LeO 451 could have been available in much larger numbers and might have been almost invulnerable over the Soviet Union...

Bombers work in the short term. If the Russians decide they have a problem, they have Spitfire_IXs. A Leo455 is not outrunning that.