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

[ThomasP]

re

Just a side (but related) question.
Did 50kg bombs make sense for Germany, taking economic constraints into account?
I might be wrong, but I recall that one of the issues with 50kg in the USSR (as an example) was industrial - more machine-hours and logistic costs vs FAB-100 and larger bombs, per the explosive mass per factory shift.

A couple of factors are involved.

1. What fabrication equipment do you have? If you have plenty of equipment available that can make smaller bombs, and a shortage of equipment that is capable of making larger bombs, the question kind of answers itself.

2. What airframes & tactics do you use for bombing, and what are the target types.

There seems to be no question that there is an optimum range for bombs that are going to be used against heavy industry and factories - the US and UK found that 500 lb were a bit too light, and tried to move to 1000 lb bombs for general attacks against heavy industry, though they still used a lot of 500 lb bombs upto the end of the war. (I believe Geoffrey Sinclair posted some numbers in either up-thread or in another thread that gives some actual numbers and sizes of bombs during the war.) 2000 lb & 4000 lb bombs were great against heavy industry, but there was a trade-off between weight per bomb and number of bombs carried to the target vs the chance of actually putting a bomb on target.

If your target is infantry and soft vehicles on the move, then a lot of smaller bombs will usually be better than a couple of big bombs. Depending on the make-up of the terrain (ie from open farmland to craggy rocky hill country) a larger number of small bombs may be significantly more likely to be effective than a couple of large ones.

I do not have any real info on the bomb sizes used by the USAF and UN forces in the Korean War, but in Vietnam the USAF/USN often carried a large number of smaller bombs, or cluster bombs, which allowed a larger pattern of shrapnel effect when the primary target was infantry on the move or attacking. Rockets were common as well of course, which can be thought of as small bombs or artillery shells delivered via rocket.

Given the above, did production of smaller bombs like the 50 kg make sense relative to the Luftwaffe's intended targets?

[edited for clarity]

 

[Shortround6]

Germans could've been much more adventurous with the 190's bomb load came 1942.
The MW 50 system for the BMW 801 engines never advanced from the experimental phase. Including the Fw 190 installations.
Germans were free to start making the Fw 190s with DB 601E and 605A in 1942, would've gotten them something between the MC.205 and Re.2005 performance-wise, and free the BMW 801s for fighter-bombers (assumes the Me 210s and daylight-role 110s are axed).

Thank you for the correction of the MW 50. Germans were great for experimenting with things. Post war writers were very good at NOT telling how many German planes did not all the bells and whistle tricks.
It may have been quite possible to use DB engines in the FW 190. For fighter-bomber use things get a little tricky. The DB engines were lighter, even with radiator/s but the heavier loads used by the kitted A-4s may not have been possible or only possible with longer runways. Germans don't have the number of bulldozers the Americans had. If we are satisfied with 250kg or max 500ikg load then it might be a good engine swap.

The B-26 is probably an example of how not to make a 2-engined bomber? Too big a fuselage for too many people, that added both weight and bulk, thus necessitating the wing to grow (again, added weight and bulk). One needs the powerful engines just to stay competitive, the powerful engines are gas guzzlers and are heavy. Adding bulk and size (= drag) several times is bad for both performance and fuel mileage.

Just using the B-26 as a short of benchmark and a good illustration (I think) of paper figures vs actual combat performance numbers. The same operation and flight instructions for the B-26 I got the weight numbers from,

https://www.wwiiaircraftperformance.com/wwiiaircraftperformance.org/B-26/B-26_Operation_and_Flight_Instructions.pdf

Gives a max speed of 326mph at 14,250ft. and a number of other performance numbers at the 26,784lb weight. Like 2500ft take-off distance to 50ft
It also gives fuel loads of 1462 US gallons/ 9,128lbs and bomb loads of over 4000lbs (including two 2000lbs bombs or four 1000lb bombs).
The numbers are there, but they were never going to be used in combat.
I have real doubts about the numbers used for the LeO 451

We are not in 1940 anymore, Toto

280-290 mph at sea level is badly under the curve in 1942. The better Allied tactical bombers can do 330-350 mph there. A tac bomber doing 350-370 mph was within the scope of German industry in 1942.

Actually 280-290 mph is not bad at sea level in 1942. A-36 was estimated to do 337mph with bomb racks at sea level, 322mph with a pair of 300lb bombs and 315mph with a pair of 500lb bombs. It was estimated about 18mph faster at around 5,000ft.
FW 190 good for just over 300mph depending on load?

The 13mm barbettes kept the crew number low, and with this the bulk and weight.

Yes it kept the crew number low but it actually didn't do a whole lot. And if we are flying at 1000ft or less why are we worrying about having a single gun pointing down at more than 60 degrees? The extreme elevation and depression only look good on paper and depend on good co-operation from the pilot (flying straight and steady).
Too much weight and complication for too little result.

 

[tomo pauk]

Post war writers were very good at NOT telling how many German planes did not all the bells and whistle tricks.

200% agreed.

It may have been quite possible to use DB engines in the FW 190. For fighter-bomber use things get a little tricky. The DB engines were lighter, even with radiator/s but the heavier loads used by the kitted A-4s may not have been possible or only possible with longer runways. Germans don't have the number of bulldozers the Americans had. If we are satisfied with 250kg or max 500ikg load then it might be a good engine swap.

My cunning plan is to have the fighter-bombers powered by the 801s, and the fighters by the 601E/605A and 801s (the V12 versions in the theaters where range is a big thing, as well as reliability of the engines in 1941-42).
Two-three 250 kg bombs, or maybe one 250 kg bomb and 4x50 kg should not over-tax the Fw 190, even the early ones.

Actually 280-290 mph is not bad at sea level in 1942. A-36 was estimated to do 337mph with bomb racks at sea level, 322mph with a pair of 300lb bombs and 315mph with a pair of 500lb bombs. It was estimated about 18mph faster at around 5,000ft.
FW 190 good for just over 300mph depending on load?

300+ mph with a 500 kg bomb and on the 2nd best engine rating (for the fully-rated 801D it was 2400 rpm, 1.32 ata) of winter of 1942/43. Bomb and rack cost was some 50 km/h (~30 mph). Three 250 kg boms will cost even more.
Upping the engine setting to Notlesitung might add 20-25 km/h.

We'd probably want a 2-engined tac bomber, outfitted with bomb bay, to do better both wrt. the bomb load and speed.
The Germans take on the 'Judy' (1-engined bomber of small size and with a bomb bay, but with protection for the fuel and crew) idea might've brought them a fast bomber on dime. On 1500 HP radial, it was supposed to do 325 mph at SL, per TAIC; similar with the last Atstutas, that were comparable with the fully-rated DB 601E or the restricted 605A. Granted, once the bobs were away, the Fw 190 or a similar fighter-bomber is much better off - as if the 'no free lunch' rule applies as ever ...
The early A-20s were in the ballpark, too, despite the bulky fuselage and engines, as well as despite the thick wing and questionable amount of the exhaust thrust.

Yes it kept the crew number low but it actually didn't do a whole lot. And if we are flying at 1000ft or less why are we worrying about having a single gun pointing down at more than 60 degrees? The extreme elevation and depression only look good on paper and depend on good co-operation from the pilot (flying straight and steady).
Too much weight and complication for too little result.

Any rear gunner will depend on the pilot flying the aircraft steady.
The barbettes were probably the least of the Me 210s worries, though.

 

[Shortround6]

Two-three 250 kg bombs, or maybe one 250 kg bomb and 4x50 kg should not over-tax the Fw 190, even the early ones.

True and the Germans had the option of using four 50kg bombs on the center rack for a total of eight. High drag but the option is there.
The US planners were happy with either as single bomb rack or a pair (mostly). It was the men in the field who went to three to six 250lb bombs. Shortage of 500lb bombs or the targets didn't require 500lb bombs? When trying to target rough airfields is the goal to crater the runway/s or destroy the parked aircraft and support structure (buildings/tents/vehicles). Concrete runways may require the 500lb or even 1000lb bombs? Troops on the march may require different bombs than troops in trenches/foxholes. Or different number of attacking aircraft.
British wound up in NW Europe with Spits carrying one 500lb and two 250lb bombs. But even the Bomphoon's could only carry two bombs. Granted the four 20mm cannon were pretty good for strafing and the British made large use of rockets. But the allies had more twin engine bombers (or 4 engine) if they really wanted to saturate an area.
Germans may have their own ideas of what bombs and numbers are needed to get the effect they want and that may depend on the type of ground (forest, swamp, wheat fields, city with stone buildings) and targets. Dug in troops, troops on the march, troops formed up to attack, supply dumps, forward airfields or larger more permanent airfields. Bridges are on their own. You need 500lbs minimum and more likely 1000lbs or bigger for large stone/cement bridges but there aren't that many of them in some areas (Africa? none) and not that many in Russia. They can be very important at times but those times are a small fraction of number of missions flown.
Ju 87s did tend to suck as the war went on but they offered a lot of options. If the fighter bombers offer fewer bomb options another bomber, of some sort, has to fill in for the rare missions.

300+ mph with a 500 kg bomb and on the 2nd best engine rating (for the fully-rated 801D it was 2400 rpm, 1.32 ata) of winter of 1942/43. Bomb and rack cost was some 50 km/h (~30 mph). Three 250 kg boms will cost even more.

We'd probably want a 2-engined tac bomber, outfitted with bomb bay, to do better both wrt. the bomb load and speed.

Kind of covered above, there is no single aircraft solution. The twins can also be based further back and use larger runways.
Soviets and Germans sometimes operated front line airfields at 3-6 sorties per day (more?) per aircraft. Easy of servicing is important and that includes "bombing up". Same number of men may be able to load four 50kg bombs faster/easier than a single 250kg bomb.
Two 7.9mm machine guns were considered enough for strafing in 1939-40, by 1942 not so good, by 1943/44 really not good. But guns and ammo cut into bomb load.

The early A-20s were in the ballpark, too, despite the bulky fuselage and engines, as well as despite the thick wing and questionable amount of the exhaust thrust.

A-20s had a lot of power.
Some wing area's of comparable aircraft.
Bf 110...............413sq/ft
Ki-48.................430sq/ft
PE-2..................435sq/ft
Mosquito........454sq/ft
A-20..................464sq/ft
Beaufighter... 503sq/ft
only a few of these made much use of exhaust thrust

Pointing the exhaust up or down doesn't do much for forward speed.
Air pressure at sea level can really cut into exhaust thrust compared to what happens at 20,000ft. On the other hand, it is cheap and light so any improvement is usually a plus.

The Germans take on the 'Judy' (1-engined bomber of small size and with a bomb bay, but with protection for the fuel and crew) idea might've brought them a fast bomber on dime. On 1500 HP radial, it was supposed to do 325 mph at SL, per TAIC; similar with the last Atstutas, that were comparable with the fully-rated DB 601E or the restricted 605A. Granted, once the bobs were away, the Fw 190 or a similar fighter-bomber is much better off - as if the 'no free lunch' rule applies as ever ...

The Judy was very good aerodynamically. As a warplane it has some problem and since everything is a trade-off fixing some of it's problems may make it less attractive for other use.
Max bombloads for non-kamikaze use include a pair of 30kg bombs under the wing. High drag but not every attack has to be high speed. Standard internal load was a single 250kg bomb, With the higher-powered engines they could use a 500kg bomb. But protection only showed up on the last versions built for the Japanese. German version can use protection but it may come at the cost of bomb load? or field length? or range? using a 254 sq/ft wing on a 10,600lb airplane works if you have a lot of runway. Germans may want more than a pair of 7.7mm-7.9mm machine guns for strafing in 1942-43. It can be done but what else is being given up?
the wing may have been small, the rest of plane not so much.

Non-flying rebuild with P&W engine. Different photos show it without the "bomb" but also without the pilot for scale.

Any rear gunner will depend on the pilot flying the aircraft steady.

true but the further off from axis of the plane the harder things get.
And are we talking about 1 on 1 duals or formation fights. If the 210s maneuver for good shots they have broken formation and should be easier to attack.

 

[tomo pauk]

The US planners were happy with either as single bomb rack or a pair (mostly). It was the men in the field who went to three to six 250lb bombs. Shortage of 500lb bombs or the targets didn't require 500lb bombs? When trying to target rough airfields is the goal to crater the runway/s or destroy the parked aircraft and support structure (buildings/tents/vehicles). Concrete runways may require the 500lb or even 1000lb bombs? Troops on the march may require different bombs than troops in trenches/foxholes. Or different number of attacking aircraft.
British wound up in NW Europe with Spits carrying one 500lb and two 250lb bombs. But even the Bomphoon's could only carry two bombs. Granted the four 20mm cannon were pretty good for strafing and the British made large use of rockets. But the allies had more twin engine bombers (or 4 engine) if they really wanted to saturate an area.
Germans may have their own ideas of what bombs and numbers are needed to get the effect they want and that may depend on the type of ground (forest, swamp, wheat fields, city with stone buildings) and targets. Dug in troops, troops on the march, troops formed up to attack, supply dumps, forward airfields or larger more permanent airfields. Bridges are on their own. You need 500lbs minimum and more likely 1000lbs or bigger for large stone/cement bridges but there aren't that many of them in some areas (Africa? none) and not that many in Russia. They can be very important at times but those times are a small fraction of number of missions flown.

FWIW, Germans in Russia figured that bombs heavier than 250 kg were not needed for the tactical targets, at least when the Hs 129s and Fw 190s are used to haul them. Granted, a really good bridge or a tough ship will require more.
250 kg was about what the 23-25cm howitzer will be launching.

Ju 87s did tend to suck as the war went on but they offered a lot of options. If the fighter bombers offer fewer bomb options another bomber, of some sort, has to fill in for the rare missions.

The Ju 87 morphed from a 'mainstream' tac bomber to a niche aircraft, that depended a lot on the enemy and weather to facilitate/enable the use case.

Kind of covered above, there is no single aircraft solution. The twins can also be based further back and use larger runways.

I agree that a 2-type approach would've gave them better results.

The Judy was very good aerodynamically. As a warplane it has some problem and since everything is a trade-off fixing some of it's problems may make it less attractive for other use.
Max bombloads for non-kamikaze use include a pair of 30kg bombs under the wing. High drag but not every attack has to be high speed. Standard internal load was a single 250kg bomb, With the higher-powered engines they could use a 500kg bomb. But protection only showed up on the last versions built for the Japanese. German version can use protection but it may come at the cost of bomb load? or field length? or range? using a 254 sq/ft wing on a 10,600lb airplane works if you have a lot of runway. Germans may want more than a pair of 7.7mm-7.9mm machine guns for strafing in 1942-43. It can be done but what else is being given up?
the wing may have been small, the rest of plane not so much.

A longer fuselage will cause far less of the drag than a longer wing
The 'German Judy' will not need to have the internal fuel load as the original; 275 US gals (almost double the fuel load of the 'normal' Fw 190) is over the top for a 1-engined tactical bomber. Self-sealing tanks will hold less fuel anyway. Reduction of, say, 125 gals = reduction of 750 lbs.
Judy went to 10000 lbs with either the drop tanks + 250 kg bomb or with normal fuel (1040L) and 500 kg bomb, while the Fw 190G-1 went to 11000 lbs (4900 kg) with two drop tanks (fuel total of 1125L) and a 500 kg bomb - IOW, the Fw 190 is the one that will ask for the longer runaway.
Germans will add protection and will swap the pop guns with 20mm stuff. The Fowler flaps and dive brakes might not be part of the design? BMW 801 will do better power than the Kinsei.
The version with the V12 in the nose should be both rangy and fast.

A 2-engined aircraft should've gave them ability to carry 4 250 kg bombs in a bomb bay (or at least in some kind of recess; other bomb load or addtional fuel as options) and still be fast enough. Having an extra engine might be a nice thing to have in a shooting war, too. British did well with the Mosquito, after all, but I'm okay with the BMW engined design, too.

 

[yulzari]

re

A couple of factors are involved.

1. What fabrication equipment do you have? If you have plenty of equipment available that can make smaller bombs, and a shortage of equipment that is capable of making larger bombs, the question kind of answers itself.

2. What airframes & tactics do you use for bombing, and what are the target types.

There seems to be no question that there is an optimum range for bombs that are going to be used against heavy industry and factories - the US and UK found that 500 lb were a bit too light, and tried to move to 1000 lb bombs for general attacks against heavy industry, though they still used a lot of 500 lb bombs upto the end of the war. (I believe Geoffrey Sinclair posted some numbers in either up-thread or in another thread that gives some actual numbers and sizes of bombs during the war.) 2000 lb & 4000 lb bombs were great against heavy industry, but there was a trade-off between weight per bomb and number of bombs carried to the target vs the chance of actually putting a bomb on target.

If your target is infantry and soft vehicles on the move, then a lot of smaller bombs will usually be better than a couple of big bombs. Depending on the make-up of the terrain (ie from open farmland to craggy rocky hill country) a larger number of small bombs vs 1 or bigger bombs may be significantly more likely to be effective than a couple of large ones.

I do not have any real info on the bomb sizes used by the USAF and UN forces in the Korean War, but in Vietnam the USAF/USN often carried a large number of smaller bombs, or cluster bombs, which allowed a larger pattern of shrapnel effect when the primary target was infantry on the move or attacking. Rockets were common as well of course, which can be thought of as small bombs or artillery shells delivered via rocket.

Given the above, did production of smaller bombs like the 50 kg make sense relative to the Luftwaffe's intended targets?

Zuckerman's studies of bombing damage make interesting reading and translated into bombing loads.