The AN/ALE-29 countermeasures chaff dispensing set is an electro-mechanical device that ejects cartridge-loaded configurations of Mk 46 or MJU-8/B decoy flares and RR-129 or RR-144 chaff.

Decoy flares burn very hot and are used during evasive maneuvers against heat-seeking missiles.  Chaff rounds consist of extremely fine shredded metal strips in a cylindrical metal container. When they are ejected, the metal strips are released which causes a cloud of reflective surfaces which appear as “static” or “snow” to a radar (either ground-based, aircraft, or missile) which in effect “masks” the movement of the aircraft for a short period of time.

Under Project Shoehorn the Navy's F-4s had this device mounted on the aft end of the engine bulge of each engine. Each unit held 30 cartridges of either flares, chaff, or a combination contained in a plastic “bucket” which was loaded into the dispenser.  The door was opened when the selector knob was turned to any setting other than off (port, stbd, or both) and stayed open until the aircraft landed and the unit was serviced.

The countermeasure material may be ejected in single or multiple salvos.  A salvo consists of a series of single bursts ejected at specific intervals.  A salvo can be ejected from a single dispenser or simultaneously from both dispensers. If an empty dispenser is selected, or if a dispenser runs out of countermeasure material during a salvo, the system automatically cascades to the loaded dispenser.

F-4B/N - AN/ALE-29 / -29A AFT Cockpit Controls

F-4B/N Rear Cockpit
"Post Shoehorn"

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1 - F-4B/N Integrated Control Panel
(controls AN/APR-27, AN/ALE-29 & AN/ALQ-51/100)

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2 - AN/ALE-29 Programmer Control Panel

F-4B/N - AN/ALE-29 / -29A External Location

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1 - AN/ALE-29 location F-4B/N left side 

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1 - AN/ALE-29 location F-4B/N right side 

AN/ALE-29 Dispenser Open (Detail)
Mirrored on other side
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Revision History:
  • 21 APR 2014 - Added more Artwork 
  • 18 MAR 2014 - Original Post
  • Artwork by Kim Simmelink
  • NAVAIR 01-245FDB-1
  • Pictures from Michael France