Lone Sentry: Use of Smoke by German Air Force (WWII Tactical and Technical Trends, No. 40, December 16, 1943)

Various German documents which have become available for examination reveal much information concerning the tactics, and apparatus employed by the German Air Force in the use of smoke. It will be noted that German and American smoke tactics are similar in many respects.

The following information obtained from German documents, was compiled in the Office of the Chief of Chemical Warfare,

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a. Weapons and Objectives

Aerial smoke apparatus can be used to establish smoke screens (a curtain of smoke extending down to the ground) and area screens (a smoke cloud extending close to the ground and covering a given area). At present, smoke does not appear to be a suitable weapon for aerial combat.

Ordinary screens are established by a single aircraft or by several aircraft following each other. Area screens, on the other hand, are produced by a number of aircraft flying in close proximity. Two means of dissemination from aircraft are available.

(1) Spray Apparatus -- Under air pressure, smoke acid, which is either sulfurtrioxide or chlorsulfonic acid or a mixture of the two, is sprayed from tanks attached to the plane. By experiments it has been found that planes spraying smoke should fly at altitudes of 130 to 165 feet or less. Another German source states that the minimum altitude for smoke cloud emission is 100 feet.

(2) Smoke Bombs -- Smoke bombs are used for establishing screens from high altitudes. Usually the filling is either smoke acid or a Berger mixture consisting of powdered aluminum and hexachlorethane. Release by aircraft is the same as for HE bombs.

b. Atmospheric Conditions

Proper evaluation of weather conditions determines the effectiveness of smoke screens produced by planes. The following data have been ascertained by experiment:

(1) Very Favorable Weather -- No wind or light wind, high humidity, atmospheric conditions of early morning and dusk, also night time.

(2) Favorable Weather -- Wind velocity from 4 to 16 mph for spray dissemination, 7 to 13 mph for smoke bomb, temperature not below 23° F, overcast sky.

(3) Unfavorable Weather -- Wind and sunlight cause convection currents ("noon weather"). Very strong wind and squally weather cause drifting and scattering of smoke. Following a dry cool night, sunlight, and medium strong wind will cause rapid dispersion of cloud ("Forenoon weather"). Heavy frost and low atmospheric humidity result in poor smoke cloud formation. Smoke dissemination may be made effective under unsatisfactory weather conditions by an adequate increase in expenditure of smoke agents.

c. Tactics

Surprise is an important factor in the use of smoke. Consequently in defense, enemy smoke on one's own positions is an imperative signal for the dispatch of one's own aerial reconnaissance. Situations which permit the use of smoke by aircraft are:

(1) Attack on Ground Targets -- In HE bombing or in strafing attacks, smoke-disseminating planes can be used to blind or neutralize the aimed fire of enemy antiaircraft batteries and thus reduce the danger to the attacking planes. However, premature employment of smoke in such cases may enable enemy planes to intercept and thus jeopardize the effectiveness of the smoke on the antiaircraft positions. The further danger exists that smoke may conceal the actual objective of the friendly planes which are attacking.

During night bombing, the use of smoke may decrease the effectiveness of enemy searchlights as well as their antiaircraft fire. Diversion screens may deceive the enemy as to the true objective of the attack.

(2) Antiaircraft Defense -- For screening of important installations, including airfields, aircraft factories, arsenals, business and industrial centers. This use requires an adequate service to warn of approaching enemy planes and a system to enable rapid response.

Area screens laid by aircraft can hamper the orientation of enemy aircraft with respect to their objective by covering an area considerably larger than the specific target. Dense masking screens may be established by mass employment of smoke. (However, in practice, the Germans seem to depend on ground means of dissemination for area smoke screens.) Even light smoke screens may suffice to render orientation difficult, but they possess the disadvantage of being rapidly dissipated. Thorough preparations are required to co-ordinate use of area smoke with antiaircraft defenses.

(3) In Support of Ground Forces -- Thorough preparation and perfect coordination with the ground forces, including a reliable communications system, are necessary. Consideration must be given to the necessity of not interfering with one's own aerial combat reconnaissance. These are some of the tasks that may be undertaken:

Observation posts of enemy artillery and machine gun emplacements may be blinded by smoke bombs. Flanking fire from sectors outside the main line of attack may be neutralized by smoke sprayed from low-flying aircraft. This can be particularly valuable in facilitating movement of units within the area under enemy observation either in attack or defense.

Similarly, to break off combat, and during withdrawal, smoke may be placed on the enemy to delay his movements and enable one's own ground troops to withdraw with a minimum danger from effective enemy fire. Consideration must be given to the possibility that smoke may limit or neutralize one's own aerial defenses and may interfere with operations in adjacent sectors as a result of drift.

d. German Aircraft Smoke Bombs

The following table identifies and describes two of the smoke bombs used by the German air force. It is probable that other bombs are available and that they may be encountered. For a detailed description of the NC 50 bomb, see Tactical and Technical Trends, No. 29, p. 27.

Bombs

Type of bomb NC50 NC250-S

Employment On land On land and at sea

Weight 110 lbs 418 lbs

Dimensions 2'2-1/2" x 8" diam ------

Markings, color Nose-white; body-aluminum color with 4 white bands, 1 in wide ------

Ballistics and suspension Same as for SC50* Same as for SC250

Fuze Mechanical tail fuze Electric contact fuze (Zd. 26)

Duration of smoke cloud 30 to 40 mins 2 to 3 mins

e. Comments

Doctrines set forth by the Germans in the documents under review are for the most part standard practice. It is questionable, however, whether the use of smoke-spraying aircraft to produce large area screens is anywhere nearly as effective as ground installations for this purpose. Actual German practice seems to confirm this.

Direct spraying of smoke on enemy ground units by low-flying aircraft to prevent flank fire during an attack would seem to be questionable tactics. The smoke-laying aircraft would be extremely vulnerable in such an operation. However, it may be intended to lay smoke in an adjoining area which will drift over the units which it is desired to blanket.

During the Grecian campaign smoke was at times used by the Germans to indicate targets. Reconnaissance planes would lay down a streamer of smoke to indicate the direction of the targets. In one case a German aircraft circled a camouflaged airfield and laid down a smoke trail. In another, a winding road was outlined for several kilometers by smoke placed over it by two reconnaissance bombers. Following shortly, 20 bombers flew over the smoke trail, 10 on each side, and dropped their bombs.

*See Tactical and Technical Trends, No. 37, p. 27.