Activation of new aaa units - Air Defense Artillery

Comments on ~~Proposed Revision of FM 4-104"
The following letters were received in arrswer to our
request for comments on the article entitled "Proposed
Bevision of FM 4-104," that appeared in the May-June
is~e of the JOURNAL:
To the Editor:
The May-June issue of the COASTARTILLERYJOURNAL
contaif!s an article titled "Proposed Revision of Field Manual
4-104" upon which comment is invited. After reading
the article, th~re are a fe'w comments I should like to offer
for what thev mav be worth.
It is appar~nt that many of the recommendations included
in the article are based on operations against V-I missiles
in the defense of Antwerp. To include information on the
defense of an objective against such weapons is appropriate,
hut I believe it should also be borne in mind that PAC of a
future war may have characteristics which depart materially
from those of the V-I, with necessary corresponding changes
in the pattern of defense, and any field manual revision
at this time should make it clear that a given type of defense
may be satisfactory for but limited categories of PAG As
a matter of fact, it is a moot question in my mind 'whether
PAC of the V-I type will ever be used again, and if tactical
concepts are built up around the characteristics of this
weapon, they may well be useless if it becomes necessary to
take defensive action in the future. For instance, had the
Germans incorporated in the V-I a weaving control 'which
would have caused it to proceed on a more or less sinusoidal
course, the tactics which ,,,ere found to be satisfactorv at
the time of Antwerp would have been practically useless.
What would have been done I do not know, but it ,,'auld
have been something other than the type of defense (and
type of fire control) which was used. In a nutshell, a held
manual should not teach us how to fight the war which has
iust ended.
Specific comments:
a. Bottom of page 39, last paragraph states "If the spare
radar." Suggest the use of a statement such as "Additional
radars used to supplement the AAIS radar net, their positions."
b. Page 41, under Amphibious Operations, Preparations.
Reportswere current from time to time during the war that
/\A gun units ,vere landed with a full complement of guns,
hut without fire control, on the theory that they could engage
aircraftby emergency means, and reinforce the field artillery
with a maximum number of guns in a ground role. Since
there is no emergency AA gun fire-control system available
at the present time which is worth using, tactics of the sort
described above actually amount to supplementing field
artillery with an eJl..-pensive, albeit long-range, gun 1vhich
cannot be used in the performance of its primary mission
\\ith any degree of efficiency. "'lhere lift is at a premium,
I believe that AA doctrine should be to ahvavs include the
firecontrol, even if by so doing one or two gti'ns per battery
lllust be omitted. This ,,:ill at least permit an active, effecth-e
AA defense to be set up, \"ith somewhat less "hitting
POwer," until such time as the remaining guns can be
landed. If, on the other hand, the ground role is para-
mount, then it should be clearlv stated that the AA units
cannot be expected to protect the beach from the attack of
enemy aircraft except at very low altitude and short range.
If there is a successful development of an on carriage firecontrol
system applicable to major caliber AA weapons; the
above comment will not necessarily hold. In addition, some
mention should be made in the n~w manual of the possible
role of intermediate caliber AA weapons which I believe
would be of considerable value in amphibious operations.
c: Page 41, under Amphibious Operations, Early Warning.
Emergency early warning in an amphibious operation
\;villnot necessarily come from a floating operations room.
d. Page 41, under Pilotless Aircraft, Additional Gun
Belts. A separation of 15,000 yards between gun belts is
proposed. This separation may not be sufficient where thedefense
includes guns of longer range than the 90mm gun.
e. Same as d, above. It is stated that normal fire control
will be by visual means with radar range. This again fails
to take into account improvements in radar characteristics,
which may make it advisable habitually to track by radar
mEans entirely.
f. Same as d, above. It is stated, on page 42, that volley
fire may be utilized with time fuzed ammunition to insure
proper 'fuze setting. The subject of volley fire has been
controVErsialfor some time, and as far as I know, has not
vet been resolved. In a study started bv the AA & GM
Branch, The Artillerv School, in 1945, th~ conclusions were
reached that vollev fire has no merit where VT fuzes are
used, or ,,,,,hereautomatic fuze setters of the type used on
the 90mm M-2 gun are used, and that its advantages were,
at best, questionable where the M-13 fuze setter on the
90mm MIAI gun is used. Be that as it may, the statement
gives a false impression that the use of volley fire will insure
correct fuze setting. In many tests conducted by the AAA
Board (now the AASTS, AFF Board No.4) during the
war, the chief causes of faulty fuze setting on the 1\1-13
fuze setter ,vere lack of proper training of the fuze setter
operators and improper fuze setter maintenance. The
great disadvantages of volley fire are that it causes a longer
dead time and decreases the fire po,yer of the battery. The
increased dead time, due to the method by which the dead
time computation is handled in the l\.1-9director, seriously
degrades the accuracy of the fuze data, so that even though
slower fuze setting resulted in zero fuze setting error ( which
it doesn't), the over-all accuracy of the fuze computation
and setting is just about the same. I believe that the statement
as made should be deleted entirel\'. If there is contrary
opinion to this, then I believe that-it should be modified
by stating that if the gun crews are not well trained and
experienced, volley fire may result in a higher percentage
of accurate fuze settings being made, but at the possible
expense of less accurate fire.
g. Same as d, above. On page 42 are gi,-en some distances
relating to siting of early waming r,lda::sand posting
of obserrers. The distances given are predicated on missiles
haYing characteristics similar to the Y-1. If the missile
speed is appreciably higher than that of the V-I, the dis-