Saturday, 19 March 2011

Structural Differences of the CH-113 Labrador and the CH-113A Voyageur

To discuss the differences between Labradors and Voyageurs, I have decided to start at the front of the aircraft and work my way to the back of the airframe. The focus for the next few blogs will deal with structural differences, while subsequent blogs will address functional and operational differences. The presentations will begin with the features of the aircraft when they were purchased, move on to aircraft features as the helicopters evolved or morphed into a single and almost identical helicopter. The presentation will end as the Canadian variants of the CH-46 are finally retired.!

Structural Differences
When purchased for the Royal Canadian Air Force and Army in 1963 and 1964 respectively Labradors and Voyageurs were easily distinguishable even by the untrained eye.  Two things that set one variant apart from the other, aside from the colour, were the extra nose glass and absence of large fuel tanks on Voyageurs. Over time the only enduring visible difference was the nose glass.  To the trained eye however, there were and are many other differences.

Discussions of structural differences will include discussion of those features that would involve or require a significant maintenance effort, an effort that possibly, but not likely could be completed at unit or even base level, to install or change.  Structural differences, for the purposes of this blog, are those differences that came about because of design input and completed at the factory or through a contractual effort. Having said that, I must tell you I served as a Search and Rescue Technician (SAR Tech) and not an aircraft technician so lack any real or perceived expertise on either airframe.!

Nose Features

To begin my assessment of structural differences, it is logical that we start at the nose and work our
way to the rear.  The nose of the Voyageur, most notably differed, from its stable mate in that it contained four extra pieces of glass the Labrador lacked. Two of the four glass panels were placed on the equipment bay door and two were placed, one on either side, of the Voyageur equipment bay door itself.

As a direct result of having four extra nose mounted pieces of glass, it also became necessary to relocate the two stability augmentation system (SAS) static ports and the two cockpit fresh air inlet vents located on the nose.  Like the Labrador, the Voyageur also had two SAS static ports and one fresh air vent on either side of the nose, although the location differed.  Not obvious is that the two outer glass panels differ in shape, while the two on the equipment bay door are mirror images of each other.  These features remained the same throughout the life of the aircraft.

It is interesting to note that, worldwide, the only CH-46 or KV-107 variant to have the extra glass in the nose is the CH-113A Voyageur. !

My collection of pictures not found on the Internet is fairly extensive, so if interested and/or requested, additional pictures can be posted that better illustrate the text. The next blog will discuss emergency exits.






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