TACAN circa 1970

[Ancient-Mariner]

Back in the early 1970s at 30MU RAF Sealand I was a Civilian Radio Tech working on TACAN.
Can anyone remember where the TACAN Coupling Unit was located on a Vulcan or a Lightning? Coupling Units, made by Smiths, were of two shapes. Either a Black Aluminium Box about 9 inches wide by 8 inches high by 5 inches deep, or the other shape, an aluminium chassis with a pressed metal rear and similar front. About 7 inches wide, 5 inches high and 5 inches deep, affixed with three screws. Both types had 4 dials on the front. I know that the Belfast had the diecast version, since for old times sake I have just bought one off eBay. The Smiths label has (Belfast) stamped on it.
Many thanks.
Clive

[ZH875]

Coupling unit in Vulcan was mounted next to the T/R in the Stbd side of the Nosewheel bay

[The Oberon]

Coupling unit in Vulcan was mounted next to the T/R in the Stbd side of the Nosewheel bay
Agreed, I changed 1 in 22 years. It took me ages to find it because nobody else could remember having changed one.

[Ancient-Mariner]

Thanks ZH875 and The Oberon
I guess that it looked like https://www.ebay.co.uk/itm/TACAN-Type-ARI18107-Coupling-Unit-Type-11920-as-fitted-to-Lightning-/223711096093?hash=item3416386d1d&_trkparms=pageci%3Ab2babf70-51cd-11ea-9bf2-74dbd18097b4%7Cparentrq%3A5515affe1700ac3d3354c035ffe559e2%7 Ciid%3A1 It may not have had the Cannon type connector on the front. Strangely, that eBay item refers to a Lightning, yet on a visit to RAF Binbrook myself and my line manager asked where the TACAN coupling unit was situated and it was NOT of that type, but the diecast unit.
https://www.google.com/search?q=tacan+coupling+unit&rlz=1C1CHBD_en-GBGB806GB806&tbm=isch&source=iu&ictx=1&fir=8-_93kOMKc5lcM%253A%252C4uMTwPD1HJEcRM%252C_&vet=1&usg=AI4_-kRg-Thyy36XSc5A2aCozKN2YQ8-cg&sa=X&ved=2ahUKEwjc49umx9nnAhV4URUIHUYKAmsQ9QEwAnoECAcQBQ#imgrc=8-_93kOMKc5lcM:

There were a few types of each, the diecast one either having two identical round multi-pin sockets or one small one large. The one I have just purchase marked Belfast had a two-gang linear potentiometer to drive two range indicators - two large sockets, the other version just a single gang for one range indicator. The large box type had syncros to drive the range display. But saying that, there was a version with a single gang potentiometer for the range indicator. ( By two gange and single gang, I am referring to a means of driving the external displays. There was also another potentiometer within as part of the analogue calculation of range.)

What always puzzled me was that in Air-to-Air Mode, the pilot would see from the Range Indicator how far the tanker was away, but no Bearing information. Sounds like fun in a Lightning with not a lot of endurance...
Clive

[Tankertrashnav]

What always puzzled me was that in Air-to-Air Mode, the pilot would see from the Range Indicator how far the tanker was away, but no Bearing information. Sounds like fun in a Lightning with not a lot of endurance...
Clive

No problem - he would be having implicit faith in the tanker navigator to give him steers to complete the RV in good time for the Lightning top up ;)

[BEagle]

No problem - he would be having implicit faith in the tanker navigator to give him steers to complete the RV in good time for the Lightning top up ;)

We had the same primitive UHF/DF and A/A TACAN installation in the VC10K for many years.

Later came a TACAN with a 'beacon' (BCN) system. If the tanker crew selects BCN / INV, then a receiver with only a basic TACAN in A/A T/R mode will receiver bearing and distance to the tanker.

The DF system in the A310MRTT covers 30-406 MHz and is vastly more accurate than that old thing we had in the VC10K. It also uses a proper RMI display for the pilots and a digital DDRMI for the ARO. This makes setting up RVs incredibly easy as the DDRMI tab also enables a continuous display of RV'B', RV'C' and RV'D' turn range data to be calculated automatically.

But realistically, modern receiver radar and MIDS information is so good that tanker controlled RVs are far less necessary nowadays than back when the earth was still cooling.