Comet 4 / 4B / 4C - Radio Rack

Radio Rack — Accuracy and Improved Detail

In all the screen shots I've published until now, the radio rack has been based on Mike Pyment's XV-814. As is often the case with museum exhibits, any re-usable equipment had been removed from the aircraft before it was dismantled, and the radio rack was pretty bare. Mike moved two large units for the Smiths Flight System from their usual position in the electrical bay, under the galley floor, to the radio rack. The result is a handsome radio rack, filled with genuine period equipment, but not necessarily the right ones in the right place!

In the last couple of years, I have found a Comet Illustrated Parts Manual that describes exactly what should be in the radio rack, and where. Having the correct equipment types, I was able to find more information about each unit, and model it.

This was also the first block of work carried out entirely in Blender (as opposed to AC3D) — hence the ease of producing clean renders, below.

Comet 4 Radio Rack

The 1958 B.O.A.C. Comet 4 had the fullest and most densely packed radio rack:

7th shelf (top): Marconi AD.2300 doppler drive unit.
6th shelf: Marconi VHF receiver (NAV 2), bearing computer and glide slope receiver.
5th shelf: Marconi SELCAL, VHF receiver (NAV 1), bearing computer and glide slope receiver.
4th shelf: Marconi VHF receivers and transmitters (COM 1 and COM 2).
3rd shelf: Marconi HF receiver, transmitter and power unit (HF 2).
2nd shelf: Marconi HF receiver, transmitter and power unit (HF 1).
1st shelf (bottom): ECKO search radar receiver and servo/synch unit.

Fig.1: Comet 4 radio rack.

Fig.2: From left to right: Ecko E182 inverter, Marconi 2880 SELCAL receiver, Marconi AD.708 marker receiver, AD.704 VHF receiver and bearing computer, AD.706 glide slope receiver.

Comet 4B/4C Radio Rack

Two years later, and the equipment specifications for the Comet 4B/4C changed. There is already a distinct thinning out of the radio rack, which has one less shelf. This enabled the large Marconi AD.712 ADF receiver units to be moved from the navigator's rack to the radio rack, and an overall reduction in size of the navigator's station.

6th shelf: STC power unit, HF 2.
5th shelf: SELCAL and intercom units, STC power unit, HF 1.
4th shelf: STC transmitter, HF2, Marconi ADF receivers 1 and 2.
3rd shelf: Collins transponder, STC transmitter, HF1, STC VHF (NAV 2) units.
2nd shelf: STC VHF units (COM 1 and 2) and VHF units (NAV 1).
1st shelf (bottom): ECKO search radar receiver and servo/synch unit.

Fig.3: Comet 4B/4C radio rack.

Fig.4: STC VHF COM sets (left) and NAV sets (right).

Comet 4C (C Mk.4 C) RAF Transport Command

These last Comets had more equipment, and greater functionality, including military TACAN and UHF communications. Even so, equipment has shrunk again, enough to fit a locker instead of the top shelves.

Elliott was a British company who (among other things) built Bendix VHF units under license.

5th shelf: Ultra intercom amlifiers, Marconi SELCAL, Plessy UHF comms.
4th shelf: Twin Collins 618T HF transceivers (all that HF stuff now in one box).
3rd shelf: Complete set of Elliott VHF COM and NAV units, Plessy TACAN receiver.
2nd shelf: Complete set of Elliott VHF COM and NAV units, Plessy TACAN receiver.
1st shelf (bottom): ECKO search radar receiver and servo/synch unit.

Fig.5: Comet 4C (C Mk.4 C) RAF radio rack.

Fig.5: Collins 618T HF transceiver. I've gone as far as modelling the Type N and BNC connectors.

Fig.6: Left to right: Elliott VHF receiver, transmitter (COM), receiver, glide slope receiver, navigation unit and marker receiver (making a complete set of VHF COM and NAV equipment); far right: Plessy TACAN unit.

All this work has been unwrapped in Blender, but not yet textured. I look forward to seeing it in colour as much as you do! Screen shots will follow ...

Next: updates and improvements for the flight navigator's station ...

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