TM 1-1500-204-23-3
b.
Aviation Gasoline. AVGAS is a mixture of
hydrocarbons. AVGAS grades which conform to MIL-G-
5572 are used to power reciprocating engine aircraft.
Although various AVGAS grades are available, grade
100/130 (green or blue) is the grade most used by the
Army. AVGAS permits high-compression, supercharged
engines to develop maximum power without pre-ignition
(knocking). The Army requirement for AVGAS is
decreasing and will be eliminated as reciprocating-engine
aircraft are phased out of the Army inventory. Detailed
guidance on specification requirements for aviation
gasoline is included In MIL-HDBK-200 (latest revision)
and FM 10-70.
(1)
AVGAS identification. AVGAS is colored for
purposes of identification. A change in color usually
indicates contamination with another product or loss of
fuel quality. Table 2-2 shows various AVGAS grades and
their identifying colors.
(2)
AVGAS volatility. Volatility is a measure of
the tendency of a liquid to vaporize. AVGAS is a complex
blend of volatile hydrocarbons that have a wide range of
boiling points and vapor pressures. It is blended to form a
straight chain of boiling points. This is necessary to
obtain the required starting, acceleration, power, and fuel
mixture characteristics for the engine. Vaporization
characteristics are shown in figure 2-1.
Table 2-1. Critical Characteristics and Specification Requirements for
Jet Fuels Used In Army Aircraft (MIL-T-5624)1
Characteristic
Specification
Test method
requirement
ASTM
Flash Point, °C (F), min
Grade JP-4
Grade JP-5
60 (140)
D93
Specific Gravity, °C
Grade JP-4
0.785
Grade JP-5
0.817/15
Specific WT/U.S.
gal
Grade JP-4
6.55
Grade JP-5
6.82
FSII, percent vol.
0.10-0.15
Gravity, °API
D287
Grade JP-4
57-45
Grade JP-5
48-36
Freezing Point, °C, max
D2386
Grade JP-4
-58
Grade JP-5
-46
Flash Point, °C, min
D56 or
Grade JP4
¾
D3243
Grade Jp-5
60
1Detailed specification is included in MIL-HDBK 200 (latest edition) and FM 10-70.
2-2
