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From: "Showa" <showa1-at-cox.net>
Subject: Re: A question of Weight. [TANKS]
Date: Fri, 6 Oct 2006 13:16:15 -0700
Reply-To: tanks-at-rctankcombat.com

 What are your thoughts of using Grade 8 bolts for road wheels instead of 
shaft or tubing ???

Kurt (at that stage myself) G
----- Original Message ----- 
From: "Steve Tyng" <STyng-at-acptrust.com>
To: <tanks-at-rctankcombat.com>
Sent: Friday, October 06, 2006 8:19 AM
Subject: RE: A question of Weight. [TANKS]

> Aahz wrote:
>> Is it getting bent from engine torque or rough terrain?
> From running into things like minivans and trees.  The idler and drive
> wheel shafts are susceptible to impact damage.  Makes sense since these
> wheels are sitting at the four corners of the tank.
> The front and rear road wheel shafts in an solid suspension design are
> susceptible to getting bent just from running around on rough terrain.
> On the T34 I had to occasionally bend them back into alignment.
> Bent shafting is all about physics.  A 120 pound tank running at 5mph
> has quite a bit of inertia.  Lets say said tank impacts a large rock on
> it's left front drive wheel while attempting to evade the Cromwell.  The
> rock is set in well compacted soil so the rock isn't moving anywhere.
> This tank is a solid suspension design so the force of the impact will
> not be absorbed by a spring or shock absorber.  The force of the impact
> has to go somewhere so IF the road wheel, shafting, shaft mounting, and
> the hull are robust enough, the force of the impact is transferred to
> the entire vehicle as it is pushed up and over the rock.  Lets assume
> this is not the case.  The builder did not heed the advice of other
> builders or suggestions on the mailing list and skimped on shafting by
> using 3/8" all-thread rod (pretty weak stuff). This tanks front left
> road wheel shaft is not rigid enough to transfer the majority of the
> impact force to the hull of the vehicle so it is absorbed by bending 1"
> up and to the rear.  This is bad enough in itself but it gets better
> (for the Cromwell that is ;-).  Since this tank is still trying to do
> 5mph with the left front road wheel out of whack, lo and behold - the
> left track has just flown off the tank!  This results in the tank
> skewing to the left and giving an easy broadside to the Cromwell that
> has just stopped outside the 5' no fire exclusion area and is letting
> loose with a volley into the hapless victim.
> The morel of the story is don't skimp on material strength.  Think of
> the point impact areas on your tank and ask yourself how they would fair
> if you dropped your tank from a 1' height onto those impact points.
> Don't forget items inside your tank like those big and heavy SLA's that
> should be blocked in place and securely strapped down.
> Steve "We Don't Battle on a Golf Course" Tyng