88mm Flak 18 projectile and case questions for beginners.

[BMG50]

I am a bit behind on 88mm rounds these days, mainly a mine and mortar man. I fancy having a 88mm flak round in the collection as an example of ordnance that the RAF had to endure when they flew missions over Europe as a conversation piece. I bought a 88mm steel WW2/Finish case with Finish markings on the side with remaining yellow paint from the projectile. I also need to get a projectile with fuze, many which i saw at the W&P show which Ben had on his stall with the square serrations around the body. Did the Germans have clear lacquered steel cases like the Finish ones and was the writing on the side of the case similar. What type of projectile and fuze would i need for this type of case. I have tried to look on previous posts but don't give the dummy's guide on the basics of 88mm Flak rounds. Can someone enlighten me a bit more.

 

[Nabob]

There could be (and probably is) a book on 88 mm ammo. To narrow it down I will talk only about ammunition for the 88 mm AA guns mark 18, 36 and 37. I will not go into KwK36, KwK 43 or Flak 41 ammo. I am counting on my colleagues here to fact check and amend this post.
Primary sources for my answer are original German manuals:
L.Dv. 4402/5 Die Munition der Flakartillerie Teil 5 Munition der 8,8 cm Flak 18, 36 und 37
H.Dv. 541/157 Merkblatt für die Munition der 8,8 cm Flugabwehrkanone 18 (8,8 cm Flak 18) und der der 8,8 cm Flugabwehrkanone 36 (8,8 cm Flak 36) 20.05.1942.
Online here: http://michaelhiske.de/Wehrmacht/Heer/HEER/HDv_481/Heft_541/Inhalt.htm
From the designation of the manuals You can see, that one is Luftwaffe (air force) and the other Heer (army) manual. The AA defence was primarily Luftwaffe responsibility so the AA units in the field were Luftwaffe units.
To narrow it a little further I will go only with yellow projectiles. There were at least 8 types of yellow projectiles 4 HE and 4 training.
8,8cm Sprgr. L/4,5 (Kz) mit eingesetzter Sprengladung – HE round with inserted explosive
8,8cm Sprgr. L/4,5 (Kz) mit eingegossen Sprengladung – HE round with cast explosive
8,8cm Sprgr. L/4,5 (Kz) Stg mit eingegossen Sprengladung - HE round with cast explosive
8,8cm Sprgr. L/4,5 (Kz) Pr.zugz mit eingegossen Sprengladung - HE round with cast explosive
The first two projectile bodies were manufactured the by conventional method the difference is only in the method of inserting the explosive. Both have a large screw at the bottom of the projectile.
Stg – stahlguss – cast steel and Pr Zugz – Presstahl Zugezogen – Pressed steel drawn are cheaper methods of manufacturing the body blanks for further manufacturing operations. They do not have the screw at the bottom, the explosive was cast from the top.
All projectile bodies were used with training ammunition:
8,8cm Sprgr. L/4,5 (Kz) (Üb.R.) - training red smoke
8,8cm Sprgr. L/4,5 (Kz) (Üb.W.) – training white smoke
8,8cm Sprgr.Patr. L/4,5 (Kz) (L.S.) – training signal (makes a bright flash explosion)
8,8cm Sprgr. L/4,5 (Kz) (Bl) – inert projectile
Great post by DJ here: http://www.wk2ammo.com/showthread.php?3579-8-8cm-practice-test-shells-for-flak-18-36-37&

So what You need is a monoogive projectile with or without base screw. Please see attached pics.

Steele cases were marked as can bee seen on Pic 010
Remember that you need mechanical screw for the case.

Now to fuzes.
The most used would be Zt.Z. S/30 with Krupp Thiel mechanism or Zt Z S/30 Fg with Junghans mechanism. For ground role it would be Az 23/28. For blind projectiles there would be inert “Ersatz” fuzes.

There is a lot of what I did not write, but this is the basic info.

Bob

 

[Fred]

Hi There
Theres not much to add to Bobs comments but all the Finnish cartridges I have encountered have a grey colour which was applied post-war. They appear to be have a grey phosphate coating with gloss lacquer on top. The lacquer is easy to remove with solvent, leaving a matt grey cartridge.
fred

 

[BMG50]

I know that the Germans used a phosphate finish on weapons later in the war. Did the Finnish refurb the cases the same way as the Germans or another method, can't believe the Germans would manufacture a steel case for combat in bare steel without a protective finish. Phosphating also needs a form of oil or paint/ lacquer on the freshly phosphated surface as the finish will absorb moisture and rust, so what is the German method of case finish for steel.
Thanks Bob for a great write up. Of the Flak shells i have seen for sale around the circuit i have seen projectiles in yellow with square serrated groves around the body, is this mainly for flak or anti personnel ground or both. I assume a non screw base projectile would show its position in the air by the smoke cloud as the projectile reached its correct height for bursting by a time fuze for the day,but what about using flak projectiles at night would there be a need for tracer and the need for a screw base. I assume a screw base projectile would be more for ground for tracer or AP but saying that, i thought more for night flak.
As for fuzes i thought a clockwork time fuze would be the type used for flak, I assume the Thiel or the Junghas type fuze, the one to fit on a flak round.

 

[Fred]

I am no expert by any means but I have seen examples of apparently original 88 cartridges with a dull or slightly shiny grey finish, not nearly as glossy as the Finnish ones. Presumably they have a light lacquer or wax on top of the phosphate . I have also encountered bare steel cases that appear to have a lacquer coating. In smaller calibres I have found bare steel cases with no protection at all, presumably relying on oil or wax.
Fred

 

[Fred]

Regarding the serrated bodies, the Germans produced controlled fragmentation projectiles with longitudinal grooves equally spaced around the body. Although they were mainly associated with AA guns they probably would be used against ground targets too. You will also encounter shells with rows of rectangular impressions around the body too. I believe these were caused when the Finns placed the shell in the chuck of a machine to remove the head for deactivation. They would also stamp the driving band with the abbreviation of a Finnish word for inert (vaara).

hope this helps
Fred

 

[Nabob]

A tracer is practical only if you aim at the target and follow it thru the sights (looking alongside the barrel). For AA role of larger guns the crew sets the elevation and deflection on the dials and set the time in the fuze setter, corrections are given by the fire direction center of the battery.
So the tracer is useful only for ground operations and is mainly used (but not only) with AP ammunition. Also this ammo is fixed in the case so the tracer must be instaled in the assembly factory, if there is a base fuze it is usualy part of a base fuze assy.

You also need that the projectile trajectory is quite flat so you can follow it in the sight picture.

The screw in the projectile base (it is really a base screwed in) is used for inserting the explosive charge (or training). It was a common pre war technology.
There was a thread somewhere on this I will just post some pictures of the charge.

The german cases I have seen were mostly very coroded. The nice ones had brass looking finish.

 

[BMG50]

After reading up, it seems that the type of AA fuze i would need for flak would be a Zt. Z S/30 time fuze which would make sense. As you would need to be a good shot to set off a flak round with a direct hit to get an impact fuze to set the round off. Flak barrages were designed not only to hit and explode near aircraft but also put off a bomb run to the target.
My next question was there a difference between AA flak 88mm rounds between early and later war ie early brass cases to late war steel cases due to cut backs on war materials and more efficient manufacture as in time saving etc. So if i bought a flak round for the collection and someone were to say, 'that's a later war flak round' what would be the difference.

 

[Tony Williams]

A tracer is practical only if you aim at the target and follow it thru the sights (looking alongside the barrel). For AA role of larger guns the crew sets the elevation and deflection on the dials and set the time in the fuze setter, corrections are given by the fire direction center of the battery.
So the tracer is useful only for ground operations and is mainly used (but not only) with AP ammunition. Also this ammo is fixed in the case so the tracer must be instaled in the assembly factory, if there is a base fuze it is usualy part of a base fuze assy.

There are other benefits to tracers on AA ammunition. If they are visible from the front, then they can have a distracting effect on bomber pilots who can see the shells curving towards them. They can also be made to provide a cheap and simple self-destruct mechanism (important when you don't want live shells falling back onto friendly heads), by providing a link between the tracer and HE compartments so that the shell blows up on tracer burnout. These SD explosions can themselves have a deterrent effect on pilots who have to fly through the bursting zone.

 

[BMG50]

Like i said you would have to a good shot or have luck for a direct hit. Tracer fire coming towards your direction would certainly divert you from a bomb run. I assume tracer would have more effect at night than day. Could you not have tracer and time fuze together rather than the tracer exploding the projectile when its depleated or the other way round depending on height.
So if i had to show or display a 88mm AA flak shell to BBC film crew or on a display to the public, what line up of flak rounds would i show that was fired at the RAF and USAAF. Seems there's more than one type

There are other benefits to tracers on AA ammunition. If they are visible from the front, then they can have a distracting effect on bomber pilots who can see the shells curving towards them. They can also be made to provide a cheap and simple self-destruct mechanism (important when you don't want live shells falling back onto friendly heads), by providing a link between the tracer and HE compartments so that the shell blows up on tracer burnout. These SD explosions can themselves have a deterrent effect on pilots who have to fly through the bursting zone.

 

[Nabob]

@Tony Williams:
I beg Your pardon, but I have to disagree with You sir.

1. Tracers are not meant to be seen from the front. Otherwise they would give up the position of the gun.
2. There is no need for SD feature in large calibre AA ammo (88 mm) as it uses time fuze for its function.
3. SD from the tracer was used mainly with small calibre ammo (to 20mm in Germany) The SD function from tracer is unreliable and if the tracer element is damaged / cracked it can lead to premature explosion. This lead to a change in Czech post war 57 mm AA gun were at first the fuze nz 20 (no SD) and SV 10 tracer with SD was used. It was later changed for the fuze nz 21 with SD feature.
4. The tracer for a weapon with 10 000 meter (32 800 ft) effective ceiling would have to be extremely large (burn time + visibility) and would limit the amount of HE sent downrange.

@BMG50:
To a BBC TV crew (and I consider BBC one of the educated TV stations) a yellow HE projectile with clockwork time fuze is more than enough.

The probability of hitting a bomber directly was about the same as hitting it with effective fragment of airburst projectile. If You dig deeper into fuzes You will find development of mech-time fuzes with sensitive impact mechanisms (ZtZ S/30CC, EDoppZ S30 etc.)

As to the date, there is usually enough markings to see the manufacture date. You do not have to get all components from the same year. More experienced collectors surely can add to this.

 

[AE501]

During WWII British infantry SAA, particularly that used in ground to ground MGs, have been fitted with 'dark ignition', that is to say there is a built in delay so that the tracer does not readily give away the point of firing. I would imagine that this is common practice for almost every army. Dark Ignition is used in a lot of direct fire ground to ground tracer ammunition.

 

[Tony Williams]

@Tony Williams:
I beg Your pardon, but I have to disagree with You sir.

1. Tracers are not meant to be seen from the front. Otherwise they would give up the position of the gun.
2. There is no need for SD feature in large calibre AA ammo (88 mm) as it uses time fuze for its function.
3. SD from the tracer was used mainly with small calibre ammo (to 20mm in Germany) The SD function from tracer is unreliable and if the tracer element is damaged / cracked it can lead to premature explosion. This lead to a change in Czech post war 57 mm AA gun were at first the fuze nz 20 (no SD) and SV 10 tracer with SD was used. It was later changed for the fuze nz 21 with SD feature.
4. The tracer for a weapon with 10 000 meter (32 800 ft) effective ceiling would have to be extremely large (burn time + visibility) and would limit the amount of HE sent downrange.

Let me quote a couple of examples to you from WW2. One concerns the naval action of 10 December 1941 in which the battleship HMS Prince of Wales and the battlecruiser HMS Repulse were sunk by Japanese aircraft. For middle layer air defence the PoW was equipped with 2 pr 8-barrel mountings, plus a Bofors gun borrowed from the army. The gunnery officer survived and wrote a detailed action report. This included the observation that the Bofors was far more effective than the 2 pr, partly because the shells had tracers while the 2 pr's did not. Incoming torpedo planes were observed to flinch away from the Bofors fire (which they could evidently see), but did not react to the 2 pr's (which they could not). This engagement happened in daylight.

The second example came from the experience of USAAC crews defending the USAAF bombers over Germany. They noted that when their .50 cal guns were loaded with tracers, the incoming Luftwaffe fighters were observed to flinch away from their fire. This was so noticeable that the USAAF developed and fielded a version of the .50 cal tracer specifically designed to be brightly visible from the front: the designation was M21 "Headlight" tracer. This proved so successful that production was increased before the end of the war. The USAAF did of course bomb in daylight.

So I think that there was a strong case for fitting all inner and medium-layer AA ammunition with tracers (and preferably SD ones). There was no question of "giving away their position" in this role - the enemy knew exactly where the targets were, they could see them!

The debate then becomes "up to which calibre would tracers be useful (with or without SD)?" I rather doubt that we have any information about that, since AFAIK no-one has tried fitting them to anything bigger than 57mm calibre and observing the results in battle. I am open to correction on that point though, if anyone has better information?

 

[BMG50]

I was reading a Lone Sentry report on 88MM ammunition stating that the Flak round had a vertical range of 32.500 feet with a velocity of 2600 feet per second, would i be correct that the flight time to reach that height would be 12.5 seconds, bearing in mind that the average bomb run was about 5km up 16,400 feet with a flak time fuze of 30 seconds.

 

[Nabob]

Thank You for the answer,
To the light and medium AA guns the tracer is obviously the only way how to adjust fire as most of the fuzes are impact initiated and the crew is (was) following the target thru the sites.
The topic shifted a little from the 88 mm question. But sticking with german AA guns the 20 mm used tracer for SD feature, the 37 mm used tracer with SD integral to the fuze, 40 mm used tracer with SD in the original and captured ammo but not in one equipped with KZ40 fuze, 50 mm tracer - SD by fuze, 88 mm, 105 mm and 128 mm no tracer - time fuze.

"To give up the position" was meant more for ground direct fire missions from concealed position. As I was never on the recieving end of the gun, I am glad to read first hand account of the action posted by You.

For the debate question: IMHO it has to do with the way the gun is directed and how the fire coordinates are determined.

Bob

 

[Nabob]

I was reading a Lone Sentry report on 88MM ammunition stating that the Flak round had a vertical range of 32.500 feet with a velocity of 2600 feet per second, would i be correct that the flight time to reach that height would be 12.5 seconds, bearing in mind that the average bomb run was about 5km up 16,400 feet with a flak time fuze of 30 seconds.

Please see the attached picture. It shows a 25 second flight time line as a finction of air density, wind direction and and muzzle velocity.
As You can see it is quite complicated computation

Bob

 

[Tony Williams]

The topic shifted a little from the 88 mm question.

Yes. There was another issue which affected 88+mm calibre AA fire, and that was concerned with the time fuzing. I understand that calculations were carried out in Germany about the effectiveness of AA fire against the heavy bomber raids and it was concluded that it would be more efficient just to fit impact fuzes. The problem was that very few shells were timed to explode at exactly the right height - nearly half of them would explode too low (and some of them would otherwise have hit their targets).

Combine this information with the tracer issue and the optimum AA system for use in 88+mm guns might have involved firing saboted sub-calibre projectiles at very high velocity, fitted with impact fuzes and big tracers. The high velocity would greatly help the hit probability, the small shell would be adequately destructive in a direct hit, and the tracer would have a deterrent effect.

 

[Martin Bull]

The problem was that very few shells were timed to explode at exactly the right height - nearly half of them would explode too low (and some of them would otherwise have hit their targets).
.

Without in any way wishing to appear flippant in a technical ( and very interesting ) thread, I'd often wondered about the old 8th AF joke ( 'Flak so thick you could get out and walk on it' ) - you can see the effect in old combat footage.

 

[BMG50]

All explained here https://www.youtube.com/watch?v=PIYVwqHM488