Number 15 Electric Fuze

48. General

Unexploded bombs of the Anti Personnel, Incendiaryor Gas types present no serious problem regarding disposaland any experiences I.O.O. (Inspecting Ordnance Officer) can deal with them on the general lines laid down in any R.A.O.S. Part III.  Incendiary bombs should be gathered together and disposed of by burning in some isolated spot.  Care should be taken not to start grass or forest fires and not too many bombs should be burned at the same time.  The burning ground should be surfaced or cleared of grass for a radius of 50 yards at least and should not be used for the disposal of H.E. or Gas bombs.  Gas bombs should be dealt with by trained Anti Gas personnel, fully equipped with the necessary protective clothing etc.

Unexploded bombs of the H.E. type present a very definite problem owing to the probability of delay fuzes or booby traps being used.  If the bomb lies in open ground it should be disposed of where it lies.  In view of the delay action, it would be preferable in such cases to mark the position and place a sentry near the spot, i.e. in a dug out at a safe distance and leave the bomb for 10 days.  Don't move it then because of the possibility of a booby trap device but carefully carry out theh arrangements laid down in Regulations and blow it up in situ.  Sandbags should be placed around the bomb and care taken to ensure complete destruction at the first attempt.

If the destruction of the bomb in the open is likely to affect important drainage, water, gas, electricity or other supplies, it may be found preferable to defer its destruction.  the spot being patrolled or otherwise protected.  The reason for suggesting this course is the difficulty of ascertaining whether or not a booby trap is fitted.  If the former, the bomb could be removed after 10 days, but risk of the latter precludes this action.  If the bomb is not in the open, the above considerations are aggravated and the best procedure to adopt must be deduced from careful consideration of all the relevant circumstances.  A number of experiments are in hand with the object of finding a solution to this problem.

49. Information

The vital necessity for the efficient functioning of the services connected with the destruction of unexploded bombs is information.  All that is available to date is contained in the preceding notes.  If the complete demobilisation of key industries due to the risk of a large unexploded H.E. bomb being booby trapped is to be avoided we must avail ourselves of every bit of information that is likely to throw light on the type of fuzes actually fitted to these bombs.  If it can be established that an unexploded bomb in a large machine shop, departmental store etc is actually a non delay, non booby trap type, its removal for disposal elsewhere becomes a reasonable proposition.  Again if it can be established that a delay fuse is fitted, it may be possible to leave it for 10 days having cleared the area and arrange for the removal at some risk of valuable articles.  A greater risk may be faced in very special and exceptional cases by the immediate removal of the bomb but this course of action should not be attempted without higher authority.

To help in the solution of these difficulties, all details of enemy bombs obtained by military personnel should be sent immediately to CIA who will collate and circulate them through the medium of these bulletins for the information of I.O.O's and Ordnance Officers generally.  Early information of this kind may be the means of saving life as the handling of unexploded High Explosive bombs is a risky business!!

An Extract From


Published May 1939 starting at Section 44.

This extract was published before the beginning of WW2.  The references to German bombs is particularly interesting for it seems the War Office didn't seem to think that the threat of unexploded bombs (UXB's) was Quote " any real problem" Unquote.

Some information published in this bulletin has been proved inaccurate referring to the number of fuzes fitted to certain German bombs.  For instance, only one fuze was fitted to the 1000kg "Herman" but two were fitted to the 250kg and 500kg bombs.  The bulletin here is reproduced as it was published in 1939 with the available information of the time.  The first paragraph verifies this as "not entirely complete"

After reading the extract it is interesting to note that most German equipment and bomb fuzes were patented here in the UK "To protect the manufacturing rights."  No-one however, thought to check the patent office at the time to find information which might have saved the lives of many Bomb Disposal personnel.

44. German Aircraft Bombs.

The following information is circulated: It is not entirely complete but will be helpful to those called to deal with unexploded bombs.

High Explosive Anti Personnel.

These are not likely to be used over towns as they are intended to burst on impact.

There are two types-  The SC10 and SC10t; the former has vanes the latter has not.  The SC10t is intended for low level attacks on personnel and has an "all ways" fuze with a short delay action on impact for the protection of the aircraft.  The SC10 has a direct action fuze.  The low flying bomber must use the SC10t bomb with a two-second delay fuze.  Troops are given some little opportunity to take coverby reason of the delay.


45. High Explosive General Bombardment Bombs.

These are most likely to be used in the attack of towns and factories.  They are fitted with the Rhinemetall electric fuze which may be set for:

  • Direct action.
  • A delay of between 10 seconds or 168 hours or even longer.
  • It may also be set with a booby trap device to prevent withdrawal or burst when the bomb is moved.

So far as is known, the external appearance is the same for all three settings.  The fuze or fuzes are positioned in the side of the bomb.  One fuse for the 50kg bomb and two for the heavier bombs. As the fuzes are placed in the side of the bomb there is no need for a direct impact to cause them to function.

The disposal of such bombs if unexploded is clearly attended with grave risks on account of the likelihood of delayed action settings or booby trap devices.

46. Incendiary.

Bombers of the Hienkel III types can carry up to eight canisters each containing fifteen incendiary bombs of the GC 50 type, i.e. up to 120 such bombs per aircraft.  A larger quantity of the smaller incendiary bomb can also be carried but the exact numbers are not known.  Incendiaries also contain a quantity of explosive to discourage the attention of A.R.P. Personnel.

47. Gas Bombs.

The only bomb known of this type is the GC 10 which is similar in shape and form to the SC10 Anti Personnel Bomb previously described.  The High Explosive charge is omitted and a gas container inserted.  The same type of fuze is used.  There are numerous reports concerning other gas bombs and gas sprays but no precise information.