American Projectiles and Explosives
Aircraft Pyrotechnics
Tracer With Two Stars Mk 4 Series
Length: 3.85 inches
Diameter: 1.52 inches
Burning time: 5 seconds
Burning time of tracer: 3-4 seconds
Height: 250 feet
Use: Double-star signals are used as a method of emergency identification of aircraft.
Projection: The Pyrotechnic Piston AN-M8 is used for fire the signal.
Description: The outer case is similar to that of the Mk 3. The star charges are contained in an inner case which also houses an ejector charge and tracer element. Star color bands are the same as the bands on the Mk 3 and, in addition, a narrower band, before the star identification bands, indicates the color of the tracer.
Color combinations are:
-Red-red with Red tracer
-Green-green with Red tracer
-Red-red with Green tracer
-Red-yellow with yellow tracer
-Red-green with Red tracer
-Red-green with Green tracer
Operation: The firing pin strikes the primer, igniting the propelling charge, which, in turn, ignites the tracer in the inner case and expels the inner case from the barrel. The tracer becomes visible after traveling about 20 feet. At approximately 250 feet altitude, the tracer ignites the ejection charge through the quick match, the stars being ignited by the ejection charge through the quick match as they are expelled from the inner case.
Aircraft Signal AN-M53 to AN-M58 Series
No picture available
Description: Signals of this series are similar to the Mk 4 series.
Star Signal Mk 6
Length: 6 inches
Diameter: 2.5 inches
Weight: 1.4 pounds
Burning time: 25 seconds
Interval between launching and suspension: 2.75 seconds
Use: Signals of this series are used primarily for emergency identification purposes at night.
Description: The body of the signal is an aluminum cylinder with a bouchon type of grenade-firing mechanism on one end and a metal cap on the other. Contained in the body are the ejection charge, the pyrotechnic candle, and a silk, rayon, or paper parachute. The type and color of the signal star are printed on the side of the cylinder. The closing cap on the lower end of the signal is embossed for night identification as fllows: red star, one dot; white star, straight line; and green star a wide "V".
All three signals have an arc of a circle, one inch in length, embossed near the edge of the cap.
Operation: The signal is initiated in the manner prescribed for all bouchon-fuzed grenades. The 2.75 second delay, having been ignited by the primer, ignites the ejection charge. The ejection charge pushes off the closing cap, expelling the pyrotechnic candle and the parachute, at the same time igniting the starting mixture through a quick match. The parachute opens and suspends the candle, which burns for 25 seconds.
Smoke Signal Mk 7
No picture available
Length: 10 inches
Diameter: 2.5 inches
Weight: 2.5 pounds
Color: Red, Yellow, Green, or Black
Burning time: 25 seconds
Use: This smoke signal is used for emergency identification in daylight.
Projection: The Pyrotechnic Piston AN-M8 is used for fire the signal.
Description: The Smoke Signal Mk 7 is the same as the Star Signal Mk 6, except for its length and the composition of the pyrotechnic candle. Also, the closing cap of the smoke signal is not embossed, but is painted the approximate color of the smoke produced.
Two-Star, Red, AN-M75
Length: 5 inches
Diameter: 1.125 inches
Burning time: 6-8 seconds
Color: Red
Height: 100-200 feet
Use: This distress signal is used as an emergency rescue signal.
Description: The signal is contained in a cylinder which houses the stars and the firing mechanism. This mechanism consists of a pull release fork and a spring-loaded firing pin.
Operation: The tape is removed from the top cover and the cover is removed. The release fork is pulled; the firing pin is released and hits the primer, initiating the delay. After two to four seconds, the first red star is ejected, and after three to five seconds the second red star is ejected.
Remarks: This signal is not procured by the Navy.
Smoke Grenades AN-M8, M16, M18, and AN-M4
Length: 5.7 inches
Diameter: 2.57 inches
Weight: 1.68 pounds
Burning time: 3.5 seconds
Delay time: 3 seconds
Use: These smoke grenades are used to attract attention to aviation personnel who have made a forced landing.
Description: The cylindrical sheet-metal case is nearly full of a solid smoke mixture. A circular zinc cup containing a starting mixture is located in a depression left in the top of the smoke mixture, and is designed to be initiated by a bouchon type of grenade-firing mechanism. Adhesive tape covers four quarter-inch holes in the top of the case until the signal is ready for firing. The grenade is painted gray and marked in yellow with one band, the symbol of the filler, "H.C.", and the word "smoke".
Operation: The release lever cotter pin having been removed, the release lever is freed by the operator as the grenade is thrown, and is forced off by the striker, which is at all times under tension of its spring. The striker moves on its hinge and fires the primer, which ignites a delay element that in turn ignites the starting mixture. The starting mixture burns through the zinc cup and starts a chemical reaction in the smoke mixture, generating considerable heat with the formation of zinc chloride. The zinc chloride escapes into the air as a gray-white smoke composed of finely divided solid particles. These particles are highly hygroscopic and become very obscuring liquid particles. The grenade burns for about three and a half minutes at full volume.
M-16 (Obsolescent): Same as AN-M8. May have red, yellow, green, orange, violet, or black smoke.
M18: Same as M-16, with burning reduced to one minute for a more dense smoke. Available colors are red, green, yellow, or violet.
AN-M4: Has a shorter fuze lever and is issued in a metal container with three flaps designed to be bent outward to provide additional bearing surface for use in mud of snow. The AN-M4 is not procured by the Navy.
Next Time: Aircraft Pyrotechnics - Drift Signals and Navy Flares (Part 1)
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