Armortek

Hi all , does anyone know for sure does the exhaust box sit 90 degrees to the ground , ie the exhaust box needs angling to achieve this or does the exhaust box remain parallel to the back end and therefore follows the same angle? Thanks

Hi John
I have the Takom Chieftain and have looked at photos and both seem to suggest that the back plate of the exhaust box is vertical, ie not at the same angle as the hull rear plate. I don’t have definitive proof as there is no full size Chieftain near me to measure but I am fairly confident I have got my exhaust box close to the original.
Regards
Steve

On the real thing, the hull rear plate is at 5deg from the vertical and the rear plate of the exhaust box is perpendicular to the horizontal, as these drawings show:

Thanks Stephen,
Looks like I got it about right.
Regards
Steve

Thanks for the replies more fettling for me then ,cheers

The next question this then creates given the thingy on top of the exhaust box , do you take the material off or add some on to create the angle ?

Hi John
Remove material from the sides and top plate
Regards
Steve

When I saw Steve N's cut on the side plates of the Exhaust box, I thought surly not something else. I'll probably be berated for saying there's not much "right" with the exhaust box is there.
It looks ok at first, then you look harder and words fail, how can it be so wrong.

If I was cut a further 10mm at an angle approx off the sides and off the top to generate the angle of the exhaust box on the tanks rear plate, I'm just going to mess up the gaps on the top plate mounting bolts, because the vent plate on the top is the wrong size and wrong shape and I'm not remaking that. Modify yes, converting five slots to four but that's it.

I've now given up with it and decided to move on. There's a big lump at the front needs attending too with an angle grinder.

John, I believe unless you are modelling a specific tank that still exists, you could have either box!

The drawing clearly shows the box is angled such that it is perpendicular to the ground but there is plenty of photos around which clearly demonstrate that some have boxes that are not perpendicular and follows the rear plate instead! Here's one possible explanation of why this could be. The costs to produce that box would have been high since wastage would have been produced in cutting the angles and different width plate would have been needed. In addition I believe that the top of this box would have had recessed allen key bolts; yet another expense! I suspect that later on, an alternative on replacement mod was made where the new box had equal width sides which would mean it would follow the rear plate and that hex bolts were used on the top which all adds up to cheaper production costs.

Just a thought!!

Your maybe right Richard, there's evidence that changes were made on later Mk's, mountings etc. Maybe the vent plate and box is a different shape on other Mk's.

Richard, would you care to share any photos which suggest there was an alternate exhaust box geometry? By the way, the pictures I posted above are selections from the original factory blueprints.

Stephen, When you look at the above picture, the two boxes either side of the exhaust box look like they are upright whilst the exhaust box appears angled in comparison.

As for the drawing, I'm sure it is original but is it the latest drawing?

Richard, you can’t go by the position of the rear bIn. In this case, the mudguard it sits on has had a biff which has forced it upwards. The one on t(e other side looks less disturbed but either way, they moved in service and we’re all too easily damaged. The Leyland drawing is for the Mk 5, which was the final production version. All later marks were conversions. The exhaust system was modified during the SUNDANCE programme, to the standard shown in the drawing. If the box was subsequently modified as you suggest, it would have required a major base workshops programme and a redesign of the internal exhaust box and pipes, which would have had major costs. I’ve never come across any records to that effect. We’d need more evidence to show there was a mod in later service. Interesting thought though and it would make life easier if it were substantiated.

Stephen, Richard has a point that the exhaust box pictured from certain angles does look angled and not perpendicular with the ground level. But your factory drawings are I suppose the grail that we all want to achieve.
The annoyance is that if you do achieve the correct alignment of the exhaust box, the vent plate supplied becomes out of position itself. It's as if it was purposely made that way to take up the extra space on the top plate.

It's easy to be mislead by perspective in photos, which is why original drawings and measurements sometimes reveal unexpected results. These two pictures are the best I can find in my database for illustrating that the side plates of the exhaust box were trapezoidal not rectangular, consistent with the drawings.

These drone shots may also help: