German bombers: relative strengths and weaknesses vs. fighter attack?

[Broadsword56]

I'm doing some research into German bombers in the Battle of Britain for a tactical board wargame, and I'm running into difficulty finding detailed enough info on the relative strengths and weaknesses of the He-111, D-17, and Ju-88.

I already have the He-111 in the game.

But I'm finding a some of the info on the web and even in period RAF sources can be inaccurate or contradictory.

In general (grossly overgeneralizing here), it's my understanding that the Do-17 was somewhat inferior to the He-111 and the Ju-88 was somewhat superior to the He-111.

So, if one were to take the He-111 as the "baseline" German bomber, how would the other 1940 German bombers compare to it in:

Vulnerability to nose-low, nose-level and nose-high attacks? (i.e., fire arc coverage)
Vulnerability to oblique-low, oblique-level and oblique-high attacks? (i.e., fire arc coverage)
Vulnerability to tail-low, tail-level and tail-high attacks? (i.e., fire arc coverage)
Relative vulnerability, once hit, of specific systems such as:
Wings?
Engines?
Fuselage?
Cockpit/Crew?
Rudder?
Elevator?
Fuel system?

I found the following diagrams of the bombers' fire arcs, but I'm not sure how to interpret what they mean for the specific strengths/weaknesses criteria I listed above.

Any info, suggestions and pointers to other sources would be w

 

[Greyman]

I'm no expert in Luftwaffe aircraft and welcome correction, but:

Generally they would all be similarly vulnerable from head-on and beam attacks -- except for the Do.17, where the radial engines would be more resistant to damage.

Against rear attack -- the crew of the He.111 and Do.17 are well armoured. Again the radial engines of the Dornier being less vulnerable than the Heinkel's liquid-cooled variety.

At this time the Ju.88 (I believe the majority, at least) only had armour protection for the pilot, and also used liquid-cooled engines.

So in terms of general vulnerability, the Do.17 was the toughest and the Ju.88 was the most vulnerable. I can't recall where I read it, but this was also hinted at by the loss ratios during the battle -- the Dornier having the lowest and the Junkers having the highest.

I don't think there is a large difference in defensive fire. Generally each aircraft can only bring one MG15 to bear against an attacker at any one time. Though I think the front gun of the Ju.88 has a particularly anemic arc.

All three had similarly protected (self-sealing) petrol tanks.

======================================================

Data from British crash surveys - August 1940 to October 1943. I only included figures from losses from fighter action. The fact that the figures go until October '43 skew things a bit -- but I imagine there weren't a lot of these three types being downed by fighters after 1940.

He.111
_44 not ascertainable
_49 engine and/or cooling system
__5 exploded or broke up in air
__1 petrol tank/lines
_20 on fire in the air

Do.17
_33 not ascertainable
__8 engine and/or cooling system
__0 exploded or broke up in air
__0 petrol tank/lines
__6 on fire in the air

Ju.88
_32 not ascertainable
_38 engine and/or cooling system
__8 exploded or broke up in air
__3 petrol tank/lines
_24 on fire in the air

 

[Broadsword56]

Thank you so much, Greyman!
This is EXACTLY the kind of material and data I needed.
If any others have anything to add, please chime in.

 

[GrauGeist]

German bombers were woefully under-armed in the way of defenses.
The Ju88, for example, only had 6 flexible MG81s - the ventral "bola" MG81Z was a twin" and they were manned by crew that had other duties. The bombardier was the front gunner, the radio operator was the rear gunner (who manned either the right or the left MG81J) and the navigator who manned the "bola" MG81Z.

The He111 was a little better in the respect that it had dedicated gunners in a few position, but the Radio Operator, Bombardier and Navigator also had to assume defensive positions. This doesn't include some He111s that had a 20mm cannon mounted in the tail.

The Do17 was also poorly defended, like the Ju88, with the 6 MG15s being operated by 3 crewmen and the same can be said for the Do215, which had only 4 MG15s manned by 3 crewmen.

Interestingly enough, one of the heaviest armed Luftwaffe aircraft, was the Bv222 flying boat, which had three MG151/20 cannons and five MG131s or the Ju290, which had six MG151/20 cannon and two MG131s.

 

[Kevin J]

As far as I can remember, the Dornier 17 had 2 things going for it: availability; dive speed. They could climb to altitude over France, then put themselves into a shallow dive over the Channel. With speeds approaching 400 mph over target they were difficult for Hurricanes to intercept. Or was that the exit speed?

 

[Shortround6]

Many of the German bombers went into the BoB (or at least ended the Battle for France) with just 3 machine guns.

Like the Do 17

The front gun could be clamped in place and used as a fixed gun.
They went to 5-6 guns but things weren't quite the improvement the numbers suggest.

and

The guy in the back (radio operator?) had to man 3 guns, the one out the rear and the ones out each side. The pilot has to fly the plane, that leaves 3 guns for 2 men. Does one man alternate between the high and low front guns or does the the man in the bottom of the plane try to turn around to man both lower guns.

I am sure the extra guns were some improvement but not twice the improvement the numbers suggest, especially against multiple attackers.

The HE 111 was similar starting with 3 guns although they often carried an extra gunner to handle the new waist guns.

The JU 88A-1 started with 3 guns, I don't how many may have gotten side firing guns but again, it was the top rear gunner/radio man the took care of them.
The A-5 introduced the two rear firing guns

Again the two (or 3) upper rear guns are handled by one man. The lower front gun, if fitted, is probably manned by the same guy who takes care of the upper front gun.

I would doubt that the lower rear position got the MG 81Z gun/s in time for the BoB or at least an appreciable number.

 

[Piper106]

Three problems with the German bombers;
1. The weapon of that time period, the MG15, was drum fed. The drum only provided about 3 seconds of firing time before it was empty. Then a break in fire while the drum was being replaced. Replacing an ammo drum while the bomber was maneuvering likely was not that easy.
2. The MG15 fired the standard German rifle caliber round, the 7.92 x 57. While it was one of the better rifle rounds, by 1940 any rifle round did not do enough damage.
3. During WW2, an un-escorted (or poorly escorted) bomber force would take heavy losses from a technically equal defending fighter force regardless of defensive armament.

As the USAAF found out 2-1/2 years later, even the B-17 armed with multiple belt fed heavy machine guns took heavy losses until they were protected by an effective escorting fighter force. The B-29 attacks over Japan late in the war, was one of the few cases where un-escorted bombers did not suffer heavy losses, but the B-29 flew above the Japanese day fighters, and then turned to attacking at night against an air force that had few nightfighters.

 

[BiffF15]

Many of the German bombers went into the BoB (or at least ended the Battle for France) with just 3 machine guns.

Like the Do 17
View attachment 530220
The front gun could be clamped in place and used as a fixed gun.
They went to 5-6 guns but things weren't quite the improvement the numbers suggest.
View attachment 530221

and

View attachment 530222

The guy in the back (radio operator?) had to man 3 guns, the one out the rear and the ones out each side. The pilot has to fly the plane, that leaves 3 guns for 2 men. Does one man alternate between the high and low front guns or does the the man in the bottom of the plane try to turn around to man both lower guns.

I am sure the extra guns were some improvement but not twice the improvement the numbers suggest, especially against multiple attackers.

The HE 111 was similar starting with 3 guns although they often carried an extra gunner to handle the new waist guns.

The JU 88A-1 started with 3 guns, I don't how many may have gotten side firing guns but again, it was the top rear gunner/radio man the took care of them.
The A-5 introduced the two rear firing guns
View attachment 530223
Again the two (or 3) upper rear guns are handled by one man. The lower front gun, if fitted, is probably manned by the same guy who takes care of the upper front gun.

I would doubt that the lower rear position got the MG 81Z gun/s in time for the BoB or at least an appreciable number.

How would you like to fly while a guy is firing a machine gun next to your right ear...

Cheers,
Biff

 

[MIflyer]

All of the German bombers pretty much had the crew concentrated in an area around the nose. The Germans argued this was good because crew could lend mutual aid and support and keep up morale. The British dismissively said it was because the Germans "liked to hold hands." But it's pretty clear that a good burst in that area could wipe out the crew.

I read of a case where an RAF Hurricane intercepted a lone He-111 and carefully shot out one engine. Then he went to the other side and shot out the other engine, and pointed "down" to the German pilot, who turned back to England and made a belly landing in a field. The German crew then lined up next to their airplane and bowed as the Hurricane flew by, obviously thanking him for not killing them. The easiest way could have been to fire along burst into the cockpit and kill most or all of them, but the Hurricane pilot did not do that.

 

[nuuumannn]

Might I suggest reading Eric 'Winkle' Brown's Wings of the Luftwaffe to get a better understanding of these machines and how they were viewed by a test pilot. Brown certainly has his critics, but his observations add a different view of how we look at these aircraft. Take this recollection of flying the He 111, for example;

"I had always admired the aerodynamically efficient and shapely Heinkel bomber which appeared to combine grace with sturdiness, and I was particularly impressed by its almost completely glazed and exquisitely streamlined fuselage nose, but on climbing into the cockpit of an He 111H-1 for the first time I was immediately made aware of the fact that the cult of streamlining was not without its snags. German designers were apparently irresistably attracted to the idea of depositing their pilots in greenhouses, a penchant which could produce its problems, and in the case of the He 111 the pilot had so much curved glass in front of him that his view ahead was rather akin to looking down a glass tunnel.

In bad weather the surfeit of transparent panels was downright dangerous and the fact that this was recognised was to be seen from the provision made for elevating the pilot's seat and controls for landing and taxiing, allowing his head to emerge through a sliding panel in the upper decking where it was in part protected from the slipstream by a small retractable widscreen. This instant Tiger Moth transformation in a frontline bomber always symbolised for me the eccentricities of functional design that the German aircraft industry seemed to come up with from time to time, and which, surprisingly enough, seemed to be accepted by the Luftwaffe."

His words on the Do 17, again an aeroplane he admired, although in the book these words are in the chapter on the Do 217;

"The girlish slenderness of line had translated over the intervening years to that of matronly corpulence; indeed, the deepening fuselage introduced with the E-series of this aeroplane was suggestive of a fairly advanced stage in pregnancy. It still looked good, however, with an aura of stolid efficiency not dissimilar to that which emanated from the Junkers Ju 88..."

Brown speaks very highly of the Ju 88, describing his first experience flying one as "a thoroughly enjoyable experience". The opinion of inadequate defensive armament was a fault shared by almost all German bombers, something that Brown acknowledges in his sections on all of them.

 

[tomo pauk]

Three problems with the German bombers;
1. The weapon of that time period, the MG15, was drum fed. The drum only provided about 3 seconds of firing time before it was empty. Then a break in fire while the drum was being replaced. Replacing an ammo drum while the bomber was maneuvering likely was not that easy.

The 'double drum' for 75 rounds was used as early as 1939 on MG 15s, at 1000 rounds per minute it will give 4.5 sec of fire. But yes, belt feed was/is superior.

2. The MG15 fired the standard German rifle caliber round, the 7.92 x 57. While it was one of the better rifle rounds, by 1940 any rifle round did not do enough damage.
3. During WW2, an un-escorted (or poorly escorted) bomber force would take heavy losses from a technically equal defending fighter force regardless of defensive armament.
...

Very true.