ABK units fitted to RNZAF Catalinas, Venturas, Hudsons, and probably Avengers and Dautlesses as used in forward areas, probably also on C-47s and C-63s, and of course F4Us/FGs. Pretty well compulsory if operating in an operational area, including transit flights. Incidentally, our NZ Vampires for most of the 1950s sported British manufactured IFF Mk. 3 units, these were equivalent to the US Navy ABK so far as I know. This was the type of IFF which became compulsory for all Allied aircraft leading up to D-Day, and remained standard all around the world by Western air forces post-war until superseded.
Getting those two bits in place was easy having the historical mounts but now it gets tricky.
The rest of the installation consists of two individual switches of the normal electrical type (one with a guard flap over it), a two button (must press both at once) switch for the destructor system (and of course you got said item for us), the inertia/impact switch for the automatic same function, and an indicator unit related to system status, not to forget that as yet I don't have the aerial.
Finding where these bits go is a problem. The Lockheed manuals don't show this stuff as it is what they call GFE (Government Furnished Equipment) which means "nothing to do with us". I've got a US set of pilot's notes for the RA-28/29 and in there is a shot of the w/o's position and it calls out a box for the "destructor circuit" but my copy is a hazy old photocopy from yonks ago and I've not found said publication online anywhere. The RAF pilots notes don't show said stuff as (typically pom) they draw a line on it not being pilot operable.
For info for folks....this destructor stuff is that the IFF was super hush-hush and so the units have a thermite charge in them. This was so that after a crash it was to be triggered either manually (by the two button press switch) or by the impact one switch. The charge incinerated/melted the contents of the T/R but the action was contained in the case with no danger to the crew or the a/c.
On the photo from last night you'll see a red letter D on the ABK which I guess indicates "destructor charge fitted" but that's my guess.
Wow this is a real win for your project. Thanks for posting the photos. Next time I’m at MOTAT I’ll have to check out NZ2031 to see if anything of an IFF is fitted aboard, now that I know where it was located. I think I’ve seen a partial control unit and impact switch in the instrument store but nothing of the transponder. Mike from Tauranga is sure to be interested to see what’s required to outfit TBF NZ2359 as well. The system of yours looks almost ready to go so I hope the D really stands for disabled and disarmed
Another Tony Agar/Ants Galbraith awesomeness! Thanks chaps.
On a related note, if anyone knows where we can get a Mk III IFF transponder (the box is an R3090, the Pom version of the ABK above) or even better a Mk IIIGR ( R3121 box) or SCR-595/695 (the 'murrican army/airforce equivalents thereof) for the Mossie any leads would be greatly appreciated. We are also after the aerial for this system.
Will have to look at the rear compartment of the Avenger and see what we can find. I know we have been given some items to be fitted in there but I haven't seen them all yet and other are working on those items so will ask some questions.
Really great work Denys and the team. It is a real credit to your perserverance with that project - a real labour of love.