German 20mm Unloaded Explosive Projectiles


I just ran across an interesting story today.

[quote]In Elmer Bendiner’s book, The Fall of Fortresses, he describes one bombing run over the German city of Kassel:

Our B-17 (THE TONDELAYO) was barraged by flak from Nazi antiaircraft guns. That was not unusual, but on this particular occasion our gas tanks were hit. Later, as I reflected on the miracle of a twenty-millimeter shell piercing the fuel tank without touching off an explosion, our pilot, Bohn Fawkes, told me it was not quite that simple. On the morning following the raid, Bohn had gone down to ask our crew chief for that shell as a souvenir of unbelievable luck. The crew chief told Bohn that not just one shell but eleven had been found in the gas tanks–eleven unexploded shells where only one was sufficient to blast us out of the sky. It was as if the sea had been parted for us. Even after thirty-five years, so awesome an event leaves me shaken, especially after I heard the rest of the story from Bohn.

He was told that the shells had been sent to the armorers to be defused. The armorers told him that Intelligence had picked them up. They could not say why at the time, but Bohn eventually sought out the answer. Apparently when the armorers opened each of those shells, they found no explosive charge. They were clean as a whistle and just as harmless. Empty? Not all of them. One contained a carefully rolled piece of paper. On it was a scrawl in Czech. The Intelligence people scoured our base for a man who could read Czech. Eventually, they found one to decipher the note. It set us marveling. Translated, the note read: “This is all we can do for you now.”[/quote]

Bohn Fawkes was a real person and is in the minnesota Aviation Hall of Fame

Interesting story, but some points bother me. If these were flak, then I’d be surprised that 20mm rounds could reach the altitude of the B-17 over Germany, but that is only a gut feeling. However, if these were at the top of their trajectory, that may explain why they penetrated the wing but remained in the tank. At these altitudes, I’d think 20mm projectiles would more likely be from a German fighter, but if so I’d expect them to have passed entirely through the fighter, unless they were also near the end of their trajectory and about to fall out of the sky.

Someone who knows the weight and MV of German 20mm Flak from the period could probably compute a max altitude.

Anyway, an interesting story.



Lew, I do not have the data and range tables for the 20mm Flak but can say that reaching a B-17 at operational altitude is to be excluded.
Also if that would have been possible then it would be extremely unlikely if not impossible to place 11 hits at these altitudes.

The likeliest is a fighter aircraft which would have strafed the B-17.

If we would have an image of these projectiles all would be clear.

As for not piercing the tank:
Once the projectile hit the rubberized tank (and did not explode) it was immerdially slowed down by the fuel. Depending on the angle of impact such a tank can pose a “long path of liquid” which might be sufficient to slow down and contain the projectiles within.


EOD, Great points. I agree that 11 hits on a single tank would have been almost impossible from the ground, even if a 20mm could reach operational altitude. B-17s with engine problems or engine damage that could not maintain altitude and speed to keep up with the formations would sometimes/often go to low altitudes to avoid fighters, which were deadly for aircraft alone at mid-altitudes. I guess this is possible by 20mm flak if the B-17 was relatively low and passed over a flak tower. No mention in the book extract that I was sent, or in what I found on the internet. No images of the projectiles, only the story.

I take your point, if it was a fighter that a hit into the fuel tank at a shallow angle could well have stopped the projectiles. I had not thought through that possibility. Still 11 close hits from a 20mm in a single burst would have been a bit surprising. Based on what I have seen in B-17 damage photos it appears that more than 3 or 4 large caliber hits in the same burst was about the most that could be expected, though that is from a relatively small set of data.

We will never know, but an interesting story. If the story is true, maybe someone has one of these “empty” loads in their collection!

Did Czech factories make 20mm during the war?



Certianly 20mm were made in Czechia and Slovakia for Germany but the Czech language label just means it was a Czech speaker being involved into this story. So it might have been forced labour or workers from a concentration camp etc. I think it will be very difficult to clear up the details.

The best thing to happen would be to find the official US Airforce report on this incident.


More to the point is whether the fuzes functioned when the wing/tank was hit. Even if the projectiles were empty of any filling, I would have expected the fuzes to have been blown out of the shell seating, whether they were nose or base fuzed.



That thought had occurred to me also. If there was a detonator, what the effect would be is pretty much up in the air. With either Flak or A/C ammo, they projectiles were undoubtedly self-destroying. What the effect would be would depend if the fuse was the mechanism for self-destruct or whether it was the projectile it self. If the latter then I guess the detonator would perhaps blow out the back of the projectile with minimum effect.

Loading the projectile without a detonator attached to the fuse would require a pretty broadly coordinated effort that would be hard to believe.

Easier to believe is that the projectiles were just inert training projectiles that were loaded by mistake in either a ground or aircraft weapon. Another possibility is that the rounds were loaded without detonators or defective detonators.

It is easy to see how the part about the note could have gotten added to the story later, either through a misunderstand or intentionally or simply because of the amount of time between the event and writing it down. I know my wife and I have stories from the same event from 20 or 30 or 40 years ago, but listening to her story and to mine, you would likely think we were talking about two different events.

I have serious doubts about the story as written, but there is no way of truly knowing what happened.



This story parallels one aspect of the movie Schindler’s List, supposedly based on a true story. In short, during WW2 German businessman Oskar Schindler acquired a factory to produce war supplies for the Nazis and he employed Polish Jews for his labor force. After witnessing the massacre of Jews from the ghetto, Schindler was ‘transformed’ in his thinking and he and his ‘employees’ started a campaign to produce defective equipment and shells for the Nazis.


Edited for content


It’s a good story but implausible. There is probably a grain of truth to it, as most far fetched stories often have, but the details have been exaggerated over the years…

I knew a guy who was a soldier in Vietnam. One night his outpost was attacked and a B-40 rocket propelled grenade hit his sandbagged bunker. It was a dud and simply buried itself in the sandbags and stuck there, right near his head. This story could easily be exaggerated to say that all of the RPG rounds fired that night were duds for some nefarious reason…




Your friend’s Vietnam experience reminded me of a personal story offered by a WW2 veteran (and cartridge collector) I was friends with until his passing almost 20 years ago.

His story:
In 1944 he was on the front lines in Italy. He was in charge of a 60mm mortar platoon and they were moving into a new firing position, on a hillside, when the Germans spotted them and opened fire on them with a 75mm gun from across the valley. He said the German gunners were very accurate and placed 3 rounds very close to the mortar position but all 3 of the projectiles failed to explode. When they decided the shelling had stopped, he and his platoon made a very hasty retreat, scared beyond belief and feeling really lucky to be alive. I believed his story then and to this day; he was not boastful nor was he an exaggerator.

Improperly set fuzes, soft soil, fuzes still in bore safe mode (if so designed), improper/bad explosive filler, ‘defective’ fuzes and/or projectiles, AP projectiles without explosive? One can only speculate as to why the projectiles did not explode.




I knew a guy who was a soldier in Vietnam. One night his outpost was attacked and a B-40 rocket propelled grenade hit his sandbagged bunker.


Just a tiny technical remark, the B-40 (RPG-2 with PG-2 grenades) is not rocket propelled.
A wide spread error often repeated - even in military environment.


Lots of interesting comments. As I indicated above, I have some trouble accepting the story as written. There is one element that argues for it’s accuracy. The author showed little knowledge of the range of 20mm Flak cartridges or their construction and the complexity of creating an inert HE projectile in the manner implied by the author. An obvious conclusion is that he didn’t really know much of anything about ammunition in general or about German WWII ammunition. How then did he, or someone who created the story of the note, know that Czechs were involved in the production of 30mm projectiles. Maybe just luck, but if so it was a really lucky guess.

None of us will ever know what the true story was.



The suggestion from EOD, that the original Air Force reports are the best way to investigate this,
is correct. It’s what I would do if I had the time and expertise. It is possible that some of the records
still may be classified.

I was able to examine the Elmer Bendiner book, “The Fall of Fortresses,” in the library, and I found
a few additional points, in addition to what was already quoted by Lew, which may be of interest.

Lew’s suggestion that the damage was due to fighter aircraft is almost certainly correct. Although
the plane encountered flak, it was severely damaged by repeated and sustained fighter attacks
on the return trip from the target, which was Kassel.

Two crew members, middle gunners, were lost. They became badly disoriented after losing their oxygen
supply, and they bailed out during evasive maneuvers, evidently believing that the aircraft was
going down. Oxygen lines to the aft sections were severed. Three other crew members in those
areas survived because although they also lost oxygen, they were wounded or trapped by damage,
and remained aboard.

Bendiner, who was the navigator, contacted former crew members in the late 1970’s as he researched
the book (published 1980). As he describes his interviews, they were not sitting in the bar telling stories,
but going through their log book entries, deciphering their sometimes cryptic notations, trying to reconstruct
the events. “We were seeking to collapse … the wind out of nostalgia, to see the war plain.” (p. 138)

It was during one of these meetings, in 1978, that the pilot, Bohn Fawkes, described the incident. Bendiner’s
account, of Fawkes telling him the story, is dramatic, perhaps melodramatic – "Over Bohn’s face there came a
characteristically odd, slightly mischievous grin. ‘You remember,’ he said, “that we were hit by twenty
millimeter shells…’”

Fawkes describes asking the crew chief, Marsden, on the morning after the mission, for a souvenir, the shell
that had penetrated the gas tank. He was told there was not one, but eleven, and that they had been
sent to the armorers to be defused.

The armorers told him that intelligence had picked them up, but would not say why. Neither would the
intelligence chief.

“Eventually, the captain [of intelligence] broke down. Perhaps it was difficult to refuse a man like Bohn
the evidence of a highly personal miracle. He swore Bohn to secrecy… The armorers who opened each
of these shells had found no explosive charge… One was not empty. It contained a carefully rolled
piece of paper. On it was a scrawl in Czech… Translated, it read ‘This is all we can do for you now.’” (p. 139)

The chapter ends there. However, recently an email has been circulating which adds an additional
sentence: “Using Jewish slave labor is never a good idea.”

If Bendiner was the source, and the email gives no other source, then someone has decided to
embellish the story.

If the story is true, which it might be, it’s highly likely that the worker was a slave, as slave labor
was predominant in the Nazi munitions plants. He, or she, may have been a Jew.

About 15 million people were forced laborers under the Nazis, including 400,000 Czechs. Of the 90,000
Jews in prewar Bohemia and Moravia, a group which includes most of the Czech-speaking Jews, about
80,000 were killed, some during forced labor.

If the story is true, then the person who wrote the note, and his or her companions, were very brave and
heroic, whether or not they were Jewish. I don’t think it honors their memory to add more to the story
than what we know.

A projectile that penetrates a fuel tank usually does not cause an immediate explosion. No oxygen.
As fuel leaks out, it finds an ignition source, and combustion starts.

A recent segment of the NOVA television program featured a material that has been developed to
make fuel tanks self-sealing, to defend against insurgent attacks. It’s pretty remarkable, the hole
seals so fast that you can’t even see it. The insurgents think they’ve missed the target.

I wonder if it is possible that the detonators on these projectiles could fire without igniting the fuel,
for the same reason, no oxygen. Would these have been high explosive detonators which do
not include an oxidizer? Perhaps some of our detonator experts know.


An English version, but here are the 2cm flak range-tables;

Working out what the terminal velocity and residual energy of the shell at different altitudes is completely beyond me.

Happy collecting,



This one is old, but I just found it and read the last couple of posts.

Thanks to everyone who posted!

As I reread the thread. it occurred to me that for a fighter to put eleven 20mm rounds into a fuel tank was a pretty impressive feat of Arial gunnery, even with a non-maneuvering target.

I doubt there is an official report that includes this information. If the story is true and Intel got involved then the information related to the 20mm projectiles would have been seperately classified and never included in the report of the flight. I suspect those files were destroyed long before they would ever have been declassified.

Still an interesting story.



Retrieving a not exploded, deformed HE shell from an air plane’s gas tank filled with gasoline or gasoline fumes is quite a difficult and dangerous task to perform. Aircraft maintenance personal surely put their lives at stake by doing this.
To be honest, I strongly doubt somebody actually performed this task. I guess many A/C returned home while being loaded with unexploded ordnance. I’ve no idea what the maintenance crew’s procedures were at that time, but I doubt they would take the time to ‘rescue’ a live shell from a already damaged fuel tank.
Probably the B-17 got hit by a stray of 20mm training projectiles from a German fighter plane, while Intell later made up the story of the ‘Czech paper note’ in order to boost morale of the flight crews.

Or is it just me being cynical…?


Realism is often mistaken for cynicism. I can picture a maintenance crew removing foreign objects when making repairs, but after taking necessary precautions.


EMZ, I think you are being cynical! I spent a long time in military aircraft maintenance beginning in 1960 so almost 20 years after this incident.

The B-17 in question was shot up to the point that it would have gone into heavy maintenance for repairs. Any fuel tank damage-like eleven holes in a tank- would have resulted in the aircraft being defueled and the tanks purged, often with nitrogen and then with air. before the tanks were open for repair. A mechanic would have entered the tank to inspect for damage. Repair on tanks is typically done from the inside so that the pressure in the tank helps seal the patch (but my experience is mostly from pressurized tanks. but in one case where they were not pressurized we tried to seal from the inside). Part of the repair process is to carefully clean any debris from the inside of the tank since it could find it’s way to a fuel pump and cause insufficient flow or failure of the pump.The USAF, and other Air Forces I am familiar with have taken sever disciplinary action ;against mechanics who have left ANYTHING inside a fuel tank!

I have been personally involved in a number of very similar actions, some from combat damage to the tanks and some from tanks being penetrated in flight or on the ground. It is not an uncommon or particularly dangerous maintenance task.

Since the Intel people apparently tried to restrict the story of the rounds, and initially refused to tell the crews, it seems unlikely that they made up a story to boost crew moral.

It is clearly possible that the fighter was using training rounds, and that the Czech note was added to the story later. It seems strange that a fighter unit in combat would have unloaded training rounds in stock. It is however possible that an aircraft could be transferred from a training unit to a combat unit with loaded 20mm, and the crew chief failed to check the weapon load.

I am pretty sure that during my tours in Vietnam and Thailand, we didn’t have TP rounds in the ordnance stocks. Perhaps the Germans may have issued them to combat units because of a shortage of combat munitions. Maybe one of our members has heard of this occurring, but I haven’t.

Others may have different experience than mine. If so it would be useful to hear it.



In Peter Labbett’s booklet on German 20mm he details an intelligence report of an attack on a MTB mid English channel, by a Luftwaffe fighter. On return to dock, the ‘unexploded’ projectiles were dug out of the woodwork and found to be practice projectiles.

Why the aircraft was loaded practice ammunition is not known. But if you’re a pilot out on a gunnery training exercise and a real target presents itself, you’re not going to turn it down.



Great data point! Thanks.

Still, I have a hard time conceiving a pilot being intentionally sent out on a gunnery training exercise in an active combat zone. I agree that a fighter pilot will seldom turn down a real target, On the other hand, I doubt an ops officer or commander would be conducting training and sending out pilots with training ammo in a location where there was more than just a pretty remote chance of encountering hostile forces. I’m sure there were training bases in Western UK that had German aircraft, probably recce, flying over on occasion, and perhaps an occasion when a German pilot in a training area, loaded with training ammo decided to fly up and take a shot at a B-17, particularly late in the war. But, I wonder how often that actually occurred. Thanks for identifying one occasion, perhaps there are others.