Did ordinance underneath an aircraft explode after being hit by anti-aircraft fire?

[Matt308]

I have a book upstairs of a renowned P-51 pilot that noted that his fighter protection ops of B-17s mission briefs included preventing Me-262s from entering the bomber formation prior to drop. This pilot indicated that the -262 pilots would wait until it was likely that the formation had armed the bombs just prior to target (not sure what implications that means) and the -262s would then dive into the middle of the formation targeting a single B-17 attempting to explode its bomb load and taking others with it. The pilot said he personally witnessed this occurring with the supposed loss of almost 100 men in an explosion and claimed that this send him into a rage to pursue a -262 back to its aerodrome. I'm sure I could find the book and passage, but it is not in front of me.

The veracity of this claim, I leave up to forum members. But I have no reason to doubt it.

 

[Shortround6]

About the only thing you can be 100% sure of when dealing with high explosives is that NOTHING is 100% sure when dealing with high explosives.

 

[GrauGeist]

It's possible, the 30mm minengeschoss round was a devestating hitter. Erich can add more info regarding it's performance, but just one hit from the 262's 30mm could break a wing off of a P-51...when they were able to land hits on a B-17 or a B-24, devestation was a result

 

[Matt308]

Yeah, I read an account of a B-29 making a bombing run over Japan. At release point, all the bombs hung up. Upon return home at lower altitude one of the flightcrew attempted to enter the bomb bay and stomp on the "offending" bomb to initiate a release to no avail. Worried about landing, they touched down and taxied to their position and shut down the airplane with nothing but wet brows. As they gathered in front of the plane and began walking away the whole bomb bay dumped onto the ground... with the whole crew reflexively going into a worthless protective crouch. Nothing happened and it turned out to be a laughable moment, thank God.

 

[GrauGeist]

And not a pair of clean shorts in the crowd...

 

[Matt308]

I wouldn't have imagined. Certainly at that point bowels take over from adrenalin.

 

[tyrodtom]

On the bombs I worked on, this was Vietnam era, but we were still using some WW2 munitions. We, I installed the boosters AND fuses on the bombs after we mounted the bombs on the bomb racks. This was on the A1s and T-28s. But on aircraft with bomb bays, the fuses were installed before the bombs were winched into the bomb bay.
Each bomb fuse had a propeller on it, the propeller was kept from spinning by a stiff wire that kept the propeller from spinning, and the wires were kept in position by clips.

When the bombs were dropped the wires stayed with the bomb rack, leaving the propeller on the bomb free to spin and arm the bomb. If you didn't want the bombs to explode, you dropped the bomb with the wire still attached to the bomb, the propeller on the fuse couldn't spin and arm the bomb.
Like I said we were still using some WW2 bombs at that time, and we used the same basic procedures with them. They were fused, when the aircraft took off. But the fuses don't arm until the bomb's forward motion thru the airstream spins the arming propeller a fixed number of turns, I think about 500 feet below the aircraft. You don't want them to arm too soon because those bombs often hit each other early in their fall from the bomb bay.

I can't imagine a WW2 crewman back in the bomb bay installing fuses, while the aircraft is flying and flak exploding all around, that just doesn't seem likely.

 

[OldSkeptic]

And don't forget the V1s, a lot of pilots lost their lives when they exploded (very common) and they were a bit too close.

The incendiaries in British bombers commonly went up too, hence the 'scarecrows' all over the sky.

 

[Matt308]

I can't imagine a WW2 crewman back in the bomb bay installing fuses, while the aircraft is flying and flak exploding all around, that just doesn't seem likely.

Perhaps I missed that statement. That surely doesn't seem likely at all. And rather silly. But a hung bomb load does seem plausible. A crewman attempting to jar them loose does seem plausible. And a subsequent dump on the tarmac does seem plausible. And them NOT exploding does seem plausible. All within the paramaters of your detonation logic. Still makes my sphincter pucker though.

 

[tyrodtom]

While I was at NKP, Thailand, the bomb dump at I think Takli had a accident, over 100 750 lb bombs went off, in one revetment.
No witnesses survived. 10 or 12 men died. It was the night crew.

These were unfused bombs, just as you store them. When the rest of that lot was examined at other bases, ( cut open) the plastic liner in the bomb that keeps the explosive out of the fissures and pores of the cast iron was found to be too thin, or not there at all in some places. That allowed the filling to get into the fissure of the cast iron inside the bomb, if the bomb was accidently handled too rough, dropped a few feet, during handling, the cast iron would flex and crush the TNT inside the fissure or fine crack. Like laying some TNT on a anvil, and hitting it with a sledgehammer.
The bombs were mass produced, the TNT is mass produced. All it took was a sensitive batch of TNT, combined with some bombs made with thin or no liners, and some rough handling.

All the bombs didn't high order, some just burst open and burned, but it threw parts of some of the pieces of the equipment at the site over a mile. Bomb dumps are always out on the edge of bases. Some RT forklift pieces made it to the barracks areas.
There was no way to know exactly what happened, but they thought somebody might have knocked a bomb off a end of a stack, or lost one off the forks of a forklift.

All of that Lot of bombs were declared Grade 3 or 4, and disposed of by EOD. And we handled every bomb with a little more care from that time on.

 

[tyrodtom]

My statement about the crewman arming the bombs inflight was in reference to your story about some Luftwaffe pilots waiting for the bombs to be armed.

The bombs had the fuses installed before takeoff, from that point on nobody has to do anything to them but drop them.


I don't think procedures would have changed that much between WW2 and the 60's.

 

[JtD]

Yes, was the same thing in WW2. There was a variety of fuses, not all needed 500ft to arm.

Interestingly, though, the Luftwaffe electric fuses were indeed only activated a short time prior to release. Maybe Luftwaffe fighter pilots chose the tactics based on that?

This P-47 had it's belly bomb first stuck and then detonate upon landing. The pilot survived.

 

[GrauGeist]

From George-Peter Eder, Me262 pilot with Kommando Nowotny:
"When I was with Kommando Nowotny, I once climbed into a B-17 formation at full throttle, led the bomber slightly and fired a short burst. The rounds exploded into the left wing and the bomb bay, as this was before they dropped thier payloads. I saw a quick flash of fire, and then, when I was still more than 500 meters away when it just exploded. I hit the rudder hard as hell, pulled up vertical and then rolled away. I could feel the concussion of the blast throw my fighter all the way over. I could see the enemy tracers going past me, as I lost control of the jet for a few seconds, but the sudden attack had caught them by complete surprise. The only damage to my jet was schrapnel from the B-17's fuselage and the fragments of the five-hundred-pound bombs that had detonated."

 

[pattle]

I know RAF bombers had bomb arming switches in the bomb aimers compartment as I have seen pictures of them, they were toggle switches with a toggle for each bomb. I thought they worked by gripping the safety pin inserted into the fuse. I have no idea how this worked on incendiaries as they were carried in dispensers, perhaps incendiaries did not require fuses as there contents became flammable when exposed to oxygen. I know the Germans used to drop what my Mum called bread baskets, she tells me that a number landed on their street and you had to cover them in sandbags asap, a man a few doors down from her dropped a sandbag on one on these bombs and it killed him.

 

[tyrodtom]

The American bombs i'm familiar with had a long stiff safety wire that went thru both the nose and tail fuse, and kept the propeller on the fuses from spinning.

If the bombardier threw the arming switch ( or the Pilot on a fighter) the arming wire stayed with the aircraft when the bomb fell away, freeing the propeller to spin. But the bomb wasn't actually armed until it fell far enough for the propeller to spin X number of turns. That usually rotated a block in the fuse between the firing pin and the initiating explosive.
If for some reason, the bombardier wanted to drop a bomb and not have it explode, he never tripped the arming switch, and the bomb fell with the arming wire still attached, and the propellers couldn't spin to arm the fuses.

IMO the bombs that went off when still in or on the aircraft didn't go off because something hit the bomb itself, the bombs were so thick, a bullet wouldn't penetrate most bomb casings, and even if it did, most high explosive is so stable even a bullet wouldn't faze it.
But the fuses are different, they've got a small amount of a fairly easy to set off explosive in them. If a bullet, or flak shrapnel, hits a fuse in the right area, it will explode.

Both bomb and fuse are mass produced, and usually by the lowest bidder.

 

[Shortround6]

There is a reason the fuses are fitted just before use (take-off) and fuses usually employ and explosive "train". A series of larger but less sensitive explosive "blocks" or charges going form the one the firing pin/mechanism hits to the one responsible for setting off the main charge in the bomb/shell.
A hit by an explosive shell close to the fuse may be enough to to cause the primer or most sensitive explosive pellet/charge to go off even if the firing pin doesn't move. this area of "influence" may be larger than the one for non-exploding bullets.

 

[bobbysocks]

tyrodtom...thanks for clearing that up for me. i thought i remembered something about the props on bombs to arm the fuse but over all the years its hard to tell if what i am remembering is correct or not..especially if its not something i researched lately. actually i think i saw them ( props ) on the bombs of a model airplane i was building when i was young and asked my dad why they were there.

if those bombs that exploded at the ammo dump were old ww2 ordnance that makes a lot of sense. even commercial grade explosives lose some stability over the years no matter how well they are stored. crunching the tnt between the folds or crease would act like a rimfire cartridge....that is tragic.

 

[tyrodtom]

Those bombs that exploded in the bomb dump in Thailand were not old WW2 bombs, they were modern bomb, M117s,designed during the Korea era.
I don't remember if they were of recent manufacture, or left over from Korea. But at the rate we were using that particular type of bomb, I would suspect they were new.

That same bomb was used until just recently.

 

[fastmongrel]

RAF Fauld explosion - Wikipedia, the free encyclopedia

The crater is now covered in vegetation and isnt as big as it once was but its still over half a mile across and 400 feet deep

 

[pattle]

The American bombs i'm familiar with had a long stiff safety wire that went thru both the nose and tail fuse, and kept the propeller on the fuses from spinning.

If the bombardier threw the arming switch ( or the Pilot on a fighter) the arming wire stayed with the aircraft when the bomb fell away, freeing the propeller to spin. But the bomb wasn't actually armed until it fell far enough for the propeller to spin X number of turns. That usually rotated a block in the fuse between the firing pin and the initiating explosive.
If for some reason, the bombardier wanted to drop a bomb and not have it explode, he never tripped the arming switch, and the bomb fell with the arming wire still attached, and the propellers couldn't spin to arm the fuses.

IMO the bombs that went off when still in or on the aircraft didn't go off because something hit the bomb itself, the bombs were so thick, a bullet wouldn't penetrate most bomb casings, and even if it did, most high explosive is so stable even a bullet wouldn't faze it.
But the fuses are different, they've got a small amount of a fairly easy to set off explosive in them. If a bullet, or flak shrapnel, hits a fuse in the right area, it will explode.

Both bomb and fuse are mass produced, and usually by the lowest bidder.

I think that V1 rockets were aimed using a similar method to this, there was kind of vane on the front of the rocket and after it had made a predetermined number of turns that was when it became armed and headed downwards.