"Renault FT - Height discrepancies puzzle" Topic

Got an intersting condundrum.

I am starting work on the casting master for the Renault FT for Kallistra. As usual, I have been looking through multiple websites, to find a general concencus and the dimensions, from which I apply to a suitable technical drawing to start work.

Nearly every source I have found so far lists the FT as being about 5m (16.ft) long (with the tail)/4.1m (13.5 ft), 1.74m (5 ft 9 inch) wide and a pretty consistent 2.14m (7ft) tall.

Now, here's the odd part.

Every single technical drawing I've looked at, when they match all the other dimensions, does not match that height. At 144th scale, 5m equates to 34.7mm, and 1.74m to 12.1mm. The height, from the base of the tracks to the top of the dome, should be (if it were indeed 2.14m) 14.9mm.

Consistently, the measurements from track to dome is more like 16.1 to 16.4 – a good 10% difference.

Now, with these things there is always some margin for error, but this is quite a large error, and a consistent one.

By co-incidence, I lucked out on finding this image, which encapsulates the problem. This drawing gives the dimensions from where they are supposed to be measured from, and has been annotated. Despite this being for apparently, some sort of LEGO competition or something, the annotated measurements are pretty damn close to the measurements for the vehicle at 144th. Note the height, labelled in the drawing as supposedly 2140mm – and the annotation of 16.9.

When the rest of the measurements are consistent with each other at scale, that 2140 mm dimension(which should be 14.9mm) is very definitely more like sixteen.

Every technical drawing and illustration I've checked has close to that set of proportions.

So, this leaves me with something of a quandry. Either every single technical drawing of the FT is wrong (which seems a bit unlikely) or the oft-quoted height of 2.14 m is wrong.

I have had a look at what photos I can of the real tank, and roughly measured the length to height and approiximated them to the scale. I have found (not unsurprisingly) something of a range, from about fifteen and a half to eighteen millimetres, based on a 5m (34.7mm) length at… But nothing that matches up with the 2.14 (7ft) figure.

(By eye, the photos look about the proportions of the technical drawings, which leads me to beleive the quoted figure is more likely to be the error; and that is going to be my working assumption, at least for the moment.)

Can anyone attempt to explain the disparity? Or perhaps locate me a source which gives a different height figure? Can the dome perhaops be set at different heights – or maybe the height figure was measured to the top of the turret, rather than the dome?

Any input would be of interest.

My first thought is that the 2.14m might indeed exclude the cupola. Can't think of an easy way to check though – maybe contact the ever-helpful staff at Bovington and ask if they could take a tape measure to theirs?

There were three different turrets fitted to the FT. The original cast turret based upon the prototype and later two "omnibus" turrets – the riveted plate Berliet turret and the cast Girod turret. Perhaps the discrepancy stems from that?

Also, references generally list the American M1917 Six Ton Tank, a license built copy, as around 7ft 6in tall.

I have found a reference online that lists the FT prototype as having a height of 2.14m while giving the omnibus turreted vehicles a height of 2.29m.

@Doms Decals

That was my first thought, too, but again fairly consistently, measureing to that point, the top of the hull is lower.

@Tachikoma.
from what I've seen, the turrets don't seem to be much different in height.

references generally list the American M1917 Six Ton Tank, a license built copy, as around 7ft 6in tall.

AAAAAAAH. Now that is interesting, since that six inches would account for the discrepency – that's a good millimetre's difference at 144, which would put you in the right ballpark – add another inch like some of the source I just looked at, and you;re well into that range.

Given that, accoprding to wikipedia, the modifications to the M1917 did not appear to be anything that would add the height, it would seem to suggest that the 7 foot height is probably just wrong. (You never know, it might be one of those cases where everyone got their measurements from the same source (or from source taht got it from the original source and so on), which was wrong itself.)

I think, then, taking that into consideration, that height sounds like it is going to be more accurate. Thanks!

Edit (you posted just as I did!):

That sounds very much like it – 2.29m would be in the magic range. And if the prototype's height was just parroted, it would make sens ewhy that figure appears everywhere.

Much appreciated!

Australian War Memorial has one, email them.
Good luck with the project.