F-86 Sabre Flight manual IFF

Discussion in 'Technical Requests' started by daveT, Oct 31, 2007.

  1. daveT

    daveT Member

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    I'm looking for a flight manual manual for the F-86A Sabre. I'm especially interested in the operation of the IFF system which was the APX-6 Transponder. I believe that it contained explosive CADs that would destroy the tuning section to prevent the unit from falling into enemy hands.
    Thanks in advance
    DaveT
     
  2. GaryMcL

    GaryMcL Member

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    Dave -

    You're right, it was the AN/APX-6 and it did have three of what the manual calls destructors controlled by the battery bus. There was an impact switch to automatically actuate the destructors during a crash landing and also a guarded switch on the IFF panel itself to manually activate them.

    The manual didn't go into any detail beyond that and there aren't any good illustrations. Interestingly, though, the manual states that if the APX-6 transponder is destroyed during flight it should be reported immediately after landing. So destruction must not have been particularly hazardous to the pilot and must not have affected any control systems to prevent a normal landing after a manual destruction.

    Hope this helps.

    Gary
     
  3. daveT

    daveT Member

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    Thanks for the input, I added the info to the story
    Mysterious Black Box Discovered at 55 year old Crash Site
    By Dave Trojan

    During an investigation of a 55 year old F-86A Sabre jet crash site near Stacyville Maine an investigator discovered an unusual electronic black box in the debris. The question was what was the box used for and why was it left at the crash site?
    The guide to the wreck site believed that the box was some kind of radio. He had originally found the black box in the debris field 50 years after the crash, but had no idea what it was. The data plate located on the side of the box was marked RT-82/APX-6 Transponder. Later, upon further research it was discovered that the APX-6 Transponder was not a radio; it was used for IFF, Identification, Friend or Foe. The unit was used to automatically identify the aircraft as friendly whenever it was properly challenged by a suitably equipped friendly air or surface force. The replies were displayed together with their associated radar targets on radar indicators. The unit also could transmit a distress code if needed. Its frequency range was 800-1300 MHz and output power was 1 K watt.
    The unit was highly classified, maybe up to Top Secret at the time (during the early 1950s) and required special handling. Early frequencies used in these sets were also highly classified and the radio operator or pilot had to carry the entire set with him if no military guard facilities were available. Codes had to be set before flight and were not changeable during flight.
    One of the most interesting things about the APX-6 Transponder unit is that they contained explosives for destruction of the tuning heads (the cavitrons) if the unit was about to fall into enemy hands. There were three Cartridge Activated Devices (CADs) in front of each of the three cavities controlled by a battery bus. The pilot could initiate detonation if the situation arose using a guarded switch on the IFF panel to manually activate them. The flight manual states that if the APX-6 transponder is destroyed during flight it should be reported immediately after landing. So destruction must not have been particularly hazardous to the pilot and must not have affected any control systems to prevent a normal landing after a manual destruction.
    There was also an impact switch to automatically actuate the destructors upon a crash landing. The unit contained three detonators that were inserted into the face of the unit and they worked like a type of shotgun shell, but they were more like the size of a .45 round to self destruct the tuning heads. The idea was to keep the bad guys from determining the operating frequency, which, at that time, was changed every day. Later on, after an intact unit was compromised, the Selective Identification Feature (SIF) coder was added to the system and the frequencies were fixed at 1030 and 1090 MHz. Mode 4 IFF came much later. The voltage required to set off the explosives was less than 1 volt. Ground technicians always kept a wary eye on the live rounds when working around the units and there are stories of them accidentally setting them off during maintenance, requiring replacement of the entire unit.
    I was surprised that the APX-6 was left at the crash site. At the time of the crash, the wreck site was very remote and very little was recovered from the crash site. The APX-6 unit may have been overlooked and laid undisturbed for more than 50 years before being uncovered. Or the unit may have been left behind because they believe that the destructors did their job. Either way, finding a piece of equipment and learning its history was a fascinating experience. I have discovered the early history of IFF and its limitations and problems.
    The APX-6 IFF Transponder was standard equipment on many military aircraft in the 1950s. The APX-6 IFF Transponder was manufactured by Hazeltine and used with AN/TPX-22 in the following aircraft: A-1, A-3A/B, A-4A, B-26, B-29, B-36, B-47, B-57, B-66, C-47, C-54, C-117, C-118, C-119, C-121, C-130, E-2, F-86, F-94, H-34, CH-37, P-3, T-28, T-33, T-38, HU-16, AF-2W, AD-5, FJ-3/4, F2H-2/2N/2P, F3H, F3D-2, F9F, F11F, HO4S-2, P2V-4/5, PBM-5S, R6D-1, ZPK.
    AN/APX-6 was found on the internet, note the three DESTRUCTORS removed. The unit was located for sale on Ebay for $10. What was once secret is now cheap!
     

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  4. koplane

    koplane New Member

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    Hi Dave:
    I am building a very detailed model of an 86F. Do you have any information for both the gun and the front electronics bay?
    I will appreciate any help
    Cheers
    Oscar
     
  5. lacrossedart

    lacrossedart Member

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