Heinkel bombs nose-up?

[Marsprojekt48]

Why were bombs loaded into the Heinkel He 111 vertically with their noses pointing up?

[Orwell1984]

This thread should help you out:
He111 bomb rack
http://forum.axishistory.com/viewtopic. ... 9&t=163962

[phylo_roadking]

..remembering too that the He 111 had a one-piece wingspar...so the bombs had to drop through it...



...and the "gap" had to be suitably braced!

[phylo_roadking]

A better view of an "original" installation - from the fuselage...



...and from below....



...the second of which allows you to see the modular sub-cells that could be fitted for smaller ordnance.

It was a "best fit" (sic!) solution - when as well as having to drop through the wingspar...the internal weight had to be carried BETWEEN the fuselage's two main bulkheads! See them nestling between the cockpit rear bulkhead, and the second bulkhead?

[phylo_roadking]

As noted above - this "solution" was modular...



...and in its later career as a transport, these could be stripped out and the gap decked over. They were also the same racks as used in the early bomber-transport version of the Ju-52...a low-wing monplane that had the SAME problem - I.E. the bombs had to drop through the wingspar!

[Marsprojekt48]

Thanks Phylo! Great, clear, detailed explanation!

[Pips]

Wouldn't such an arrangement make for poor bomb fall trajectory? Bombs when released would tumble and (I would imagine) fly off the bomb line. Would make accuracy difficult.

[phylo_roadking]

Wouldn't such an arrangement make for poor bomb fall trajectory? Bombs when released would tumble and (I would imagine) fly off the bomb line. Would make accuracy difficult.

Yes! I've seen it said on AHF that it would make for increased accuracy...posters forgetting that being dropped tail first they'd turn over before falling to earth nose-first...and Heinz Novarra has THIS to say of the Ju52 "bomber" in his book in the Ju 52...

The Ju 52 was in now way suitable for the accomodation and horizontal carriage of even small (5- kg) bombs, since the distance between the wing centre crossmembers, which traversed the fuselage at a distance apart of about 800mmm, was so small that with the best will in the world even small bombs could not be released horizontally. Horizontal release, however, was regarded as vital for the accurate aiming of bombs. In this repsect the negative judgement of the Heereswaffenamt was quite understandable; on the other hand, we at Junkers had never for one minute considered the possibility of using the Ju 52 for military purposes. When, after the war, East German newspapers stated that the Ju 52 was from the outset intended as a "terror bomber" this was an unfounded and nonsensical invention.

Since the Luftwaffe wanted to start series production of bombers at an early date but had no other suitable model at its disposal, a vertical release mechanism, and consequently the vertical release of bombs, was chosen as a way out; this solution resulted in impaired aiming accuracy. As a result, Heereswaffenamt, and Reichsluftfahrtministerium concentrated on the speedy development and testing of vertical bomb racks, which were able to hold either one 250 kg bomb or four 50 kg bombs. Two vertical bomb racks fitted exactly between two main crossmembers and the bombs could be released so as to fall between the gaps. between the three main supports a maximum of eight bomb racks for eight bombs of 250 kg or 32 bombs of 50 kg could be fitted.

[Marsprojekt48]

So why not nose down? Even better than horizontal, I would think?

[phylo_roadking]

Well - look closely...



...I'm surmising that the BoB-era Sc250 as loaded nose-mounted suspension lug UP into a Heinkel bomb cell would have been held relatively rigidly inside the cell by the tail...which is after all just steel plate. Thus is had the bomb shackle at the top holding one end firmly, and the tail holding the bottom end in place in the square-section bomb cell.

If it was the other way round - I.E. all the "support" at the top...the main body of the sc 250 might have been freer to thrash around just a bit - with somewhat nasty effects on the fuses!

[Marsprojekt48]

I'm not convinced and need to talk to Ernst Heinkel right away. Do you have his e-mail?
BTW your posts are excellent, very clear, complete and with just enough detail.

[John T]

So why not nose down? Even better than horizontal, I would think?

The Germans thought it was better with nose up.

The Bomb had virtually no speed when entering the slipstream and if the fin came out first the bomb turned at lowest possible speed. It did wobble but in a more predictable manner until speed had built up and tailfins had compensated the transients. While The American way of dropping the bombs nose first had a risk that the bomb might tumble in a less predicatabel manner(according to the Germans).

According to page 41 of Wolfgang Fleischer " Die deutche Abwurfamunition bis 1945"



http://www.raf.mod.uk/blog_Image.cfm?im ... E6F01EAE59

[Defiant]

I love this subject! I read somewhere once that the RAF, having returned a crashed He111 to flight during the Battle of Britain conducted extensive technical tests on the bombing capabilities of the 111. It was reasoned early on that although understanding why the bombs were stored vertically, nose up the bombing accuracy must suffer as a result. The RAF boffins assumed that due to the wing spar design the bomb system was a compromise which the Luftwaffe overcame by formation discipline and weight of numbers! The tests, albeit with dummy practice bombs showed on almost every occasion the Heinkel outperformed all British bombers of similar Weight and size. From memory tests were conducted against a Wellington and a Hampden from identical heights and speeds. Not only was it found that the German bombsight was more efficient, there was substantially less bomb drift from the Heinkel. The bottom line being: The RAF tech heads reported that as the bombs turned from tail down to nose down they assumed their terminal velocity sooner and drifted left or right far less than if dropped horizontally. Maybe the fin design on the German bombs helped in this regard? Ironically During the height of the Blitz He111s began carrying up to two 1000kg bombs (2000lbs), of course these had to be carried externally which meant they were released in the conventional manner, horizontally.

It's interesting that the other two bombers on the Luftwaffe's roster, te Do17Z and te Ju88 stored their missiles in the more conventional manner yet were fairly efficient bombers when used in their primary role of close support.

[phylo_roadking]

Maybe the fin design on the German bombs helped in this regard?

I've often seen it said that the RAF began the war with a large stock of rather outmoded old thick-cased 250lb and 500lb G.P. "iron" bombs actually dating back to developments in the mid-'20s to replace WWI ordnance, SO many that they were still in use at the end of the war! It took some time for new munitions to arrive, in the shape of the various MC bombs starting in 1943, plus TALLBOY, GRANDSLAM, and of course...the HC cookies - which had NO fins!

http://www.wwiiequipment.com/index.php? ... &Itemid=60

http://www.wwiiequipment.com/index.php? ... ut=default

Looking at Brian Lavery, the RN experimented twice in the summer of 1940 with it's versions of the same munitions, and suprisingly found them to be not as useful as expected against landing barges at sea

So, I wonder if these results...

there was substantially less bomb drift from the Heinkel. The bottom line being: The RAF tech heads reported that as the bombs turned from tail down to nose down they assumed their terminal velocity sooner and drifted left or right far less than if dropped horizontally. Maybe the fin design on the German bombs helped in this regard?

...were due to good German design - or bad (outdated) British design?

[Defiant]

I've often seen it said that the RAF began the war with a large stock of rather outmoded old thick-cased 250lb and 500lb G.P. "iron" bombs actually dating back to developments in the mid-'20s to replace WWI ordnance, SO many that they were still in use at the end of the war! It took some time for new munitions to arrive, in the shape of the various MC bombs starting in 1943, plus TALLBOY, GRANDSLAM, and of course...the HC cookies - which had NO fins! :

An interesting comment, PRK. As I read it occurred to me that Bomber Command really did lag behind in many respects, not the least being it's ineffective GP bombs which often failed to explode, I cite a raid by Bristol Blenheims on Willemshaven in which a warship was hit by at least two 500lb bombs but failed to explode. Obviously what was considered acceptable between the wars was to leave both sides lagging as warfare developed into the modern era. The Short Stirling is a good example in this respect. Here was a bomber, considered by many pilots to be the finest aircraft ever built yet it was hampered from its earliest design stages by the inept thinking of senior RAF staffers. A potentially war-winning design that suffered due to its inability to climb to high altitude and an inability to be adapted to the later bombs being introduced as the RAF caught up.