[Milsurplus] [ARC5] Arrival of a RU-18! now DF loop which one?

[Mike Morrow]

Ed wrote:

> Arrival of a RU-18! now DF loop which one?

The WECo RU-18 is a LIAISON version of the RU-series receivers, The RU-18 SYSTEM is designed for 14 vdc and uses receiver CW-46048D. (The RU-19 uses the same CW-46048D receiver in a SYSTEM designed for 28 vdc by using heater voltage dropping resistors in the system junction box, plus a 28 vdc dynamotor.)

The RU-18 system is NOT designed for COMMAND service using a GF-series transmitter.  Instead of a GF transmitter, the RU-18 system dynamotor and junction box can supply a second CW-46048D receiver.  The liaison transmitters most commonly used with a RU-18 receiver are the Westinghouse GO-9 and GP-7.

The DF loops that would be used are the manually-positioned DU-1 or -2 locally-trained loop inside the cockpit of single-engine aircraft with radio operator, or the electronically-similar manually-positioned outside airframe loop DW-1 in larger patrol aircraft.  In single-engine carrier-based aircraft the DU-* loop disappeared as it was replaced by the ZB-* VHF homing adapter, which similarly fed the RU-series receiver.

> Interesting the RU-18 is a TRF set...did not realize that.
> We have some sets of coils and would like to get some of
> the control boxes and dynamotor to display with it.

The principal items needed for a RU-18 liaison receiver SYSTEM are:

CW-46048D      Receiver RU-18 (1 or 2)
CW-62007A      System Junction Box
CW-21215A      Dynamotor
CW-23087       Control Box (1 or 2)
CW-47###       Receiver Tuning Coils (19 different)

NONE of these RU-18 LIAISON set components are interchangeable with visually similar COMMAND SET components of the GF-11/RU-16.  Receiver coil sets are interchangeable.
 
> Would also be nice to get a companion transmitter to go with 
> it as we  did  with the  ARC 5  stuff.  Need power connectors
> and control boxes test stuff etc...

The easiest and smallest authentic LIAISON transmitter is the GP-7.

CAY-52173A     Transmitter-Rectifier
CAY-23219      Pilot's Control Box
CAY-23220      Operator's Control Box
CAY-47125      MF Antenna Tuning Unit
CAY-4715#      Transmitter Tuning Units (6 different)
 
>  Did they use these throughout the entire war...

Yes.

> ...or were they replaced by ARC 5s?

There were NO receivers of this LIAISON type that got replaced by ARA or AN/ARC-5 units...those are COMMAND service systems.

Competing and more modern LIAISON receiver SYSTEMS were the GE RAX-1 and to lesser extent the RCA ARB.  (Theee is a photo somewhere on the net of a USN LTA airship with GP-7 and ARB installation, and use of the ARB with the Collins ATC was common.)  A.R.C.'s eight-receiver RAV was intended for liaison service to replace the liaison RU-series, but the RAV rightfully failed in competition with the significantly superior RAX-1.

There are different-design COMMAND versions of the RU-series receivers that support an associated GF-* transmitter instead of a second receiver.  The most commonly-encountered systems are the WECo GF-11/RU-16 (14 vdc) and GF-12/RU-17 (28 vdc).  Compare the components of the COMMAND set GF-11/RU-16 below to the components of the LIAISON set RU-18 above.

CW-46051A      Receiver RU-16
CW-52063A      Transmitter GF-11
CW-62008A      System Junction Box
CW-21109A      Dynamotor
CW-23049       Antenna Relay
CW-23096A      Receiver Control Box
CW-23097       Transmitter Control Box
CW-23098       Extension Control Box
CW-47###       Receiver Tuning Coils (19 different)
CW-471##       Transmitter Tuning Coils (8 different)

None of these components are interchangeable with those of the RU-18, except receiver coil sets.

Mike / KK5F