CH-113 Labrador external details

[Whirly]

Hello, I have a query for Labrador aficionados, no, not the dogs....

 

I'm speaking of the Canadian Boeing Vertol V-107, especially in its earliest form when it still wore the original livery in red, and blue.

I'm putting the finishing touches to a model I built here for the Helicopter / Autogyro / STOVL GB and I got curious about the strange aerials just behind the cockpit. Those on the left are simmetrical and can be seen in the first few years of service (late '60s - early '70s) while the strange plate came later and I think is only on the left side (on the right there would be the cabin door in the same position).

Well, I can't remember anything similar on other helicopters, who know what they are?

 

 

Again speaking about details, what is that black vent(?) in the rear pilon? No other V-107 incarnation has it and it disappeared together with the above aerials when the fleet was upgraded and repainted in yellow in 1981.

 

 

 

 

 

[Patrick Martin]

      The first antenna on 402 looks just like the Search and Rescue and Homing (SARAH) beacon system, it was an emergency locater device carried by many RCAF aircraft.  The beacon itself was small enough to be carried in a Mae West life jacket, with an up-to 20-hour-transmitting battery life.  The receiver-equipped (searching) aircraft would have a set of forward-facing bi-lateral antennae and would fly along the proposed route of the missing aircraft or conduct a search pattern around the last known location of a missing aircraft - hopefully with a SARAH beacon in operation.  The receiver operator, looking at a scope, would be able to tell if a radio signal was coming from left or right, until the location was overflown - in theory.  In practice, it was not that simple, as geography and the angle at which the transmitter was sitting could at times make for large errors.

      The system was used by all larger RCAF aircraft types involved with the search and rescue (SAR) role (mainly the search portion) including; Argus, Canso, Labrador, Lancaster and later the search and rescue (SAR) role North Star. 

[Whirly]

Thank you Patrick, not only for identifying the first antenna but also explaining its purpose and functioning, always nice to know.

Knowing what to look for, now I found similar devices in other RCAF planes:

Canadair C-4

http://silverhawkauthor.com/images/site_graphics/Aircraft/Aircraft---Canada/Canadair-C-5-North-Star--Experimental-and-Proving-Establishment--26-July-1949---MIKAN-No--3584272.jpg

Canso

http://silverhawkauthor.com/images/site_graphics/Aircraft/Aircraft---Canada/Boeing-Canada-Canso-A-RCAF--Serial-No--11005-.jpg

 

It was also used in the much older Boeing SB-17G and I remember struggling with its complex and delicate shape when I built one many moons ago, fortunately the Labrador ones are much simpler!

 

And what can you say about the second antenna? I saw it described as an 'HF antenna' but seems quite generic to me. Did it replace the arlier apparatus and how did it work with a single receiver?