Nomenclature

When under development, Army bombs carry temporary desginations which are later dropped when the bombs are standardized. Experimental bombs are indicated by the let-ter "T" (e.g. T9); modification incorporated in the basic design carry the letter "E". If the developmental bomb is standardized by the Army through the Ordnance Technicak Com-mittee, the "T" designation is dropped and an "M" number is assigned. When a modifica-tion on a standard item is under development, the change will be given an "E" designa-tion; if the bomb thus modified is adopted as standard it will take a designation in se-quence in the "A" series (AN-M66A1, AN-M66A2) indicating an alteration in the basic design.

In undertaking the development of a new bomb, the Navy Bureau of Ordnance assigns a Mark number which will designate the bomb in the experimental stage as well as in ser-vice use. No system of "T" designation is employed. When adopted as standard by the Joint Aircraft Committee, the prefix "AN" is placed before the M or Mk designation.

Anti-Ricochet Attachments

To give a more vertical impact to 100 lb., 250 lb., and 500 lb. G.P. bombs and to break their descent when dropped from low-flying planes, the M16 and M17 anti-ricochet devi-ces have been developed. The device consists of a parachute unit, a modified AN-M112A1 series tail fuze (M151) using an anemometer type arming vane, and a fuze adap-ter.

Status

Where possible the status of each bomb has been given according to Navy definition "Service" indicates that the item is under current procurement. "Obsolescent" indicates that the bomb is becoming obsolete, that no future procurement is contemplated, but that large stock may be on hand. "Obsolete" indicates that the present stock is almost exhausted and that it will not be replenished. Items of Army design not procured by the Navy are not classified

Clusters, Cluster Adapter

An attempt has been made to differentiate between "clusters" and "cluster adapters". Properly, the cluster adapter is merely the containing device or holder; when the adapter is loaded with bombs, the entire assembly becomes a cluster. In some cases the cluster adapter may closely resemble a bomb in construction (e.g. M15 and M16), while in others the adapter is nothing more than a banding arrangement (AN-M1A1, AN-M4).

Practice Bombs

The mose common practice bomb for Army use is the M38A2, from which the Colored Smoke Streamer M87 was developed (page 323), simulatin general purpose bombs. Other Army practice bombs are the M48 (simulating the AN-M41A1 20 lb. Frag, page 87); the M71 and M73 (simulating the AN-M40A1 23 lb. Para-Frag, page 89); and the M85, a sub-stitute for the M38A2 (see pages 45 and 325). The M75, similar in construction to the M84 Target Identification Bomb (see page 321) is used to furnish a target reference for practice bombing over snowcovered ranges. Navy practice bombs are described and dis-cussed on pages 32 and 33.