Why Gun Tractor Shape

[Richard Scott]

https://www.awm.gov.au/collection/C2135093

The 'beetle back' pattern was so named because of its distinctive sloping rear section, manufactured between 1938 and 1944. The unique shape was derived from a design to make the vehicle easier to decontaminate in the event of a gas attack. The 'beetle back' Quad is believed to be the only vehicle to employ this design feature.

from Australian War memorial web site

[Lang]

Ah, the origin of the gas decontamination furphy. There are hundreds of misnamed or misidentified photos and objects in the AWM. Mike Cecil would know more than most that a degree in museum or film conservation does not a military expert make.

Apart from the fact the sloping back made almost no difference to any washing with 2/3 of the upper surface still horizontal, a division might have 3,000 vehicles but the only ones they wanted to wash down easily were 100 gun tractors?

Lang

[Hanno Spoelstra]

To add to the confusion, some sources state the "The Canadian Chevrolet CGT Artillery Tractor came with both a fully armored cabin and a partly armored one"

Hope the confusion is complete now!

H.

[Mike Cecil]

Lang,

To be fair, the AWM were not the originator of the furphy about the shape being for gas decontamination, but made the error of quoting an otherwise reputable source without checking or thinking about it. The origin, as far as I can make out, was as indicated by this post in another MLU thread:

"Reference to the design shape is contained in a Mechanisation Board minute featured in Ventham and Fletcher’s Moving the Guns : the Mechanisation of the Royal Artillery, 1854-1939, p81...."

And I agree with you: just because an individual is in the employ of the AWM (or any other military oriented museum) does not mean he or she has a sound knowledge of military matters or history.

Mike

[Hanno Spoelstra]

Originally Posted by Mike Cecil

The origin, as far as I can make out, was as indicated by this post in another MLU thread:

"Reference to the design shape is contained in a Mechanisation Board minute featured in Ventham and Fletcher’s Moving the Guns : the Mechanisation of the Royal Artillery, 1854-1939, p81...."

Here is a cross link to the relevant posting in the thread AWM acquisition?.

Thanks for bringing that source up again, Mike.

HTH,
Hanno

[rob love]

Reading that link, I would say it is a mis-interpretation by the author. Here I have copied the relevant part:

A clue to the origin of the curious "beetle shape of the guy ant, and other quads, is contained in the Mechanization Board report for 1939 which states:
"To permit decontamination, an all metal body to the Chief Superintendent of Design's was fitted, involving an increase of weight of 17cwts"

Thus, the characteristic shape of these vehicles was born of the need to be able to wash down the vehicles to rid them of chemical contamination......

Now if you take away the author's interpretation of that, here is the actual line from the Mechanization board report:

"To permit decontamination, an all metal body to the Chief Superintendent of Design's was fitted, involving an increase of weight of 17cwts"

My un-learned view of that line was that they previously had wood in the Chief Superintendent's design of the body, or that the Chief Superintendent of Design has changed the design to get rid of the wood. Note that in the photo of an early Guy Ant on the previous page, the body was made of wood. Wood, being porous, does not lend itself well to decontamination, so they instead changed the design to all metal, which made the bodies heavier.

The author of that book, I believe, has made a mistake in his interpretation, and that interpretation has been blindly repeated and accepted for fact. Using the word "thus" in his leap does not make it fact.

[Hanno Spoelstra]

Originally Posted by rob love

Reading that link, I would say it is a mis-interpretation by the author. Here I have copied the relevant part:

Now if you take away the author's interpretation of that, here is the actual line from the Mechanization board report:

"To permit decontamination, an all metal body to the Chief Superintendent of Design's was fitted, involving an increase of weight of 17cwts"

My un-learned view of that line was that they previously had wood in the Chief Superintendent's design of the body, or that the Chief Superintendent of Design has changed the design to get rid of the wood. Note that in the photo of an early Guy Ant on the previous page, the body was made of wood. Wood, being porous, does not lend itself well to decontamination, so they instead changed the design to all metal, which made the bodies heavier.

The author of that book, I believe, has made a mistake in his interpretation, and that interpretation has been blindly repeated and accepted for fact. Using the word "thus" in his leap does not make it fact.

Rob, I fully agree with your line of reasoning!

H.