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Bomb Size?

tigbrand

tigbrand

Well-Known Member
Premium Member
Can anybody give an approximate idea of how to estimate the size of bomb dropped by the size/depth of the crater produced? I understand this will vary depending on ground conditions,height of drop etc,but just a rough idea so i can gauge some biggish ones on some publicly accessable ex WW2 range sites in Dorset. Alternatively I can get site pics with scale next week if that would help?? Serious replies please,not supposition! Thanks in advance, Tig.(Ashley Walk Bombing range,Arne peninsular decoy site, Studland Heath training area,Ballard down Range,Crichel down bombing Range,Chesil beach bombing range.)
 
If the craters were fresh you could use some of the old period frament ID guides, they frequently gave information on estimation of size, depth, direction of travel, etc. If you are talking about WWII then suposition is all you are likely to get. Not only do you have all of the factors you already mentioned, but you also have weathering effect, which is also dependent upon all you mentioned previously and more. No scientific or technical methodology exists that I am aware of.
 
These figures are from FM 9-40, Explosive Ordnance Reconnaissance and Disposal, March 1953.

Crater Diameters in Feet

10-20 ft 100 lb. GP bomb
10-30 ft 250 lb. GP bomb
10-35 ft 500 lb. GP bomb
15-50 ft 1000 lb. GP bomb
20-60 ft 2000 lb. GP bomb

As you know the variables in size are soil type, depth of penetration and size of the bomb. The crater diameter will usually increase with the depth of penetration to a point when further penetration will actually result in a smaller diameter crater. That point, of course, is one that really can't be determined except by analysis of craters in a specific soil/geographic area and alittle knowledge of the bombs dropped in the area. It depends on bomb size, bomb impact velocity, soil type, bomb construction, etc. That is why the 10 foot minimum size can be found in three different sized bombs. Not sure this is of any help to you because it is not an exact science. Bob
 
Frags;

Look for bomb fragments, they may be a clue to bomb size, especially tail fins.
John
 
excellent

Many thanks for the above info,i understand there are many variables,but didnt realise that even a small bomb could make such a large hole,will take some site pics to add to this and see if you guys can elaborate. Thanks for taking the time to reply. Tig:tinysmile_fatgrin_t
 
Hi
(sorry for my English)
In the W.Fleischer's book "German Air Dropped Weapons 1919-1945" there are some pre-war data for SC bombs. The height of drop and type of soil aren't precised, unfortunately.
The crater size is:

for SC 50, instanteous fuze - diameter 2,4 m (6 ft), depth 0,8 m (2,7 ft)
for SC 50, delayed fuze - diameter 5,4 m (18 ft), depth 2,4 m (6 ft)
for SC 250, instanteous fuze - diameter 4,4 m (14,7 ft), depth 1,5 m (5 ft)
for SC 250, delayed fuze - diameter 9 m (27 ft), depth 3,5 m (11,7 ft)
for SC 500, instanteous fuze - diameter 5,6 m (18,4 ft), depth 2 m (6,6 ft)
for SC 500, delayed fuze - diameter 10,5 m (34,5 ft), depth 4 m (13,1 ft)

I have also some data for Russian bombs, from A.B. Shirokorad book "Wooruzenie sovietskoi aviacii 1941-1991" (Soviet air force weapons). I try to find it and write something later.
 
Suffolk Aviation Heritage Group is investigating a site known to have been bombed by German dive bombers during WW2. We have a reconn photo taken a few days later which show bomb craters around a building which exists today; so we can accurately scale the craters as between 20ft and 24ft in dia. The bombs were dropped from below 1000ft into sandy soil. Can anyone give a clue to what size bombs they were? We know that they were either Sc250s or Sc500s
 
Hello diver,

Thanks for the link, but having looked at it, I realised that we've already referenced that website without finding the info we need.
 
What's the exact info you need SuffAv?

Maybe somebody could help you if you give some more specific details about the needed info.
 
diver,

The specific details required are as mentioned in my first posting, that we are trying to ascertain which of the two bomb sizes - Sc250 or Sc500 - would make a series of craters of more than 20ft in dia when dropped from below 1000ft into sandy soil. We are hoping that either sufficient data exists concerning differing WW2 bomb sizes and soil types etc, or that someone might have sufficient expertise to provide a reliable opinion.

Cheers,
SuffAv
 
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