F-22 Plus-Up Environmental Assessment - Joint Base Elmendorf ...

Table 2. Characteristics of RR-188 or RR-170 Chaff
Attribute
Aircraft
Composition
Ejection Mode
Configuration
Size
Number of Dipoles
Dipole Size (crosssection)
Impulse Cartridge
Other Comments
Source: Air Force 1997
RR-188
F-15C, F-15E, F-22A
Aluminum coated silica
Pyrotechnic
Rectangular tube cartridge
8 x 1 x 1 inches
(8 cubic inches)
5.46 million
1 mil
(diameter)
BBU-35/B
Cartridge stays in aircraft; less interference
with FAA radar (no D and E bands)
RR-170 A/AL chaff is similar to RR-188 except that RR-170 A/AL is combat coded chaff to reflect
tracking radar. RR-170 A/AL has approximately 400,000 dipoles, each in 8 cuts. Other than the
cut of the dipoles, RR-170 A/AL chaff is essentially the same as RR-188 chaff in materials and
cartridge design. A felt spacer, 1-inch x 1-inch x 1/8-inch end cap, a 1-inch x 1-inch x 1/4-inch
piston, and the chaff dipoles are dispersed when the chaff bundle is deployed.
The F-22 uses the same chaff material in a slightly different chaff cartridge to expedite clean
ejection of the chaff. The chaff cartridge design is less likely to leave debris of any kind in the
dispenser bay yet still provides robust chaff dispensing. Figure 2 is a photograph of an F-22 chaff
cartridge. The RR-180/AL for F-22 use has chaff packaged in soft packs that have a somewhat
fewer number of dipoles per cut when compared with RR-170 chaff.
RR-180/AL chaff is similar to the RR-170 A/AL chaff cartridge with the primary exception that
RR-180/AL chaff is contained in a dual chaff cartridge (see Figure 2). The dual chaff cartridge is a
1-inch x 1-inch x 8-inch cartridge with a plastic separator, or I-beam, dividing two hyperfine (0.7
millimeter diameter) chaff cartridges. The I-beam separator uses some space and the RR-180/AL
chaff has approximately 340,000 dipoles each. Figure 2 presents the RR-180/AL chaff plastic
cartridge, two pistons with attached felt spacers, and two end caps also with attached felt spacers,
and the chaff dipoles before dispersion. Each of the two end caps and pistons is an approximately
1/2-inch x 1/4-inch x 1-inch plastic or nylon piece with attached felt spacer which falls to the
surface when each chaff bundle is deployed. There are three parchment paper wrappers
measuring approximately two inches by three inches in each of the dual chaff cartridge tubes.
This parchment paper wrapping prevents the premature deployment of chaff too near the F-22
chaff distribution rack (Air Force 2008).
A2
Chaff Ejection
Chaff is ejected from aircraft pyrotechnically using a BBU-35/B impulse cartridge. Pyrotechnic
ejection uses hot gases generated by an explosive impulse charge. The gases push the small
piston down the chaff-filled tube. In the case of F-22 chaff, six paper pieces, two small plastic end
cap, and two small plastic or nylon pistons are ejected along with the chaff fibers. The plastic
F-22 Plus-Up Environmental Assessment
Appendix A Characteristics of Chaff Page A-3