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From: "Heidi/Nick Hoke" <kingstonhokes-at-comcast.net>
Subject: Bob Griffin's Chieftan 900
Date: Wed, 4 Aug 2004 09:17:43 -0700
Reply-To: tanks-at-rctankcombat.com

Bob Griffin over in the UK is building a fine model of a Chieftan 900.


I emailed him some questions about his project and here is a compilation
of his several replies:

Length 50"              Width 23"       Height to hull top 11"

Turrret is being worked on so can't include it in the height figs

The turret is built as is all the tank from  marine plywood covered
with several layers of glass mat then several layers of finishing mat,
 then lots of wet n dry, followed by several layers of a almost water
like epoxy the aircraft guys use, this gives a smooth hard finish.

Don't know how much you know of the real thing or the model so
here are a few bits about them.  Chieftain 800/900 were attempts to
sell a chobam armoured vehicle to current chieftain users, in the end it
all fell through. Only one of each were built and the 900 I beleive is
on the tank ranges waiting to be destroyed while tank museum has the 800.

The model has full working suspension simulating the hydrogas units
that were fitted at one time.  Alluminium cast track, CNC machined wheels
with all the correct markings on the cast onto tyres. Barrell is aluminium
with rifling at the last few inches it recoils a scale 33.3 cm by means of a
industrial servo. Traverse is provided by means of a window winder motor
from a car and the turret sits on a specially designed nylon turret race.

Stabalisation is provided by two on board computers (built by my friend
who is building TOGS Chieftain) motive power is provided by two invalid
chair motors. The vehicle is being built in the configuration when it was
fitted with the GEC/Marconi fire control system, so three very large sight
heads, one for cmdr one for gunner and TI independant sight on loaders
side.  This will allow me to fit a spy camera that will be slaved to the gun
and picked up by a receiver with the main r/c kit so the public will have
an idea of what it is like to look through a gunsight.

Twin turbo fans blow smoke through the exhausts, and although it kept
the orginial chieftain exhaust sytem the power pack was in fact a derated
version of the challenger pack.

In between moving to a larger house so not a lot done for a while, but
plenty of planning goes on.

The exhaust system will be fully functional and proprotional, my friend who
building the TOGS Chieftain has the same barrel with a paint ball gun fitted
and the same type of recoil system will be used on it.

Both barells elevate as per the full size vehicle and are controlled by the
on board
computer to give full stabalisation.

The soleniod is mounted below the centre line of the gun and has an arm the
from the soleniod shft and fits into the rear of the barrel(TOGS version is
going to be
different and will use 2 soleniods) twin springs are fitted to return the
gun to the run
out position. All this is mounted on a alluminium cradle which also is the
monting points
to the turret. Gun is bolted to a industrial draw runner (type wit ball
race) and bang
away she goes.  it is far more accurate than the sytem employed by Tamiya.
When that
120mm goes of life happens in nanoseconds and that barrel flies back.  About
the only
part i have not recreated is if you see film of Chieftain firing you will if
you are quick see
that the last part of runout is very slow, this is the design in the sytem
to stop metal to
metal hard impact.

Best Regards

Bob Griffin