| From: | "Chrysanthos Kanellopoulos" <xchrysk-at-otenet.gr> |
| Subject: | Track Questions [TANKS] |
| Date: | Mon, 16 Oct 2006 22:18:09 +0300 |
| Reply-To: | tanks-at-rctankcombat.com |
|
Hey Michael,
I've noticed from experience that rear drive (for my primitive models) is
safer. It depends more on laws of nature. With a rear drive, like in T-34s and
Universal Carriers, and Abrams, and a number of other vehicles, the sagging is
on the top, and the weight of sagging track stretches the track. With a
rear drive system you can enjoy all the benefits of a very loose track, on a
rough terrain. Nothing is on the way. WIth return rollers, there is a lot of
extra track, a surplus of loose track to cause problems, potentially, like throw
a track.
With a front drive, the "sagging" of extra track, is
between the drive sprocket and the front ground wheel. See in attached jpeg what
happens with an obstacle ( I experienced it with my first RC all steel
Sherman). As you said, the drive sprocket PUSHeS the track over the obstacle,
and in between the sproket and front ground wheel. In my Sherman the track was caught there and wound around the back of
the sprocket. Di-sa-ster!
The vehicle won't roll over the rolling "ramp" of sloping track in this
front part. The front ground wheels will suffer a major shock. The tank actually
has to climb one step up.
In the other jpg, you see how the weight of the track (with blue , in the
middle, above) works as a secondary tensioner. It stretches the track from
either side / direction around the wheel. WIth red arrows, the force of the rear
drive system, always PULLS the track from the front of the vehicle. The track is
pulled firmly, yet with some tolerance and elasticity, from both red and blue
forces around the front and rear wheels. And yet, with a rear drive, I drive my
tank on very rough terrains with very loose tracks as shown in the third
attachement.
I hope that helps
CHrys
2 I've
noticed that full-scale tracked vehicles can be either front-drive or
rear-drive. The engine seems to be always at the same end as the drive
wheels, but I'm not sure whether, in general, the engine location determines the
drive-wheel location or vice versa. (I did read once that the Merkava is
front-engined, and thus front-drive, in order to provide additional protection
for the crew from frontal assault.) It seems to me that, if you want
to have slack in the track---see previous question---the track system will work
better FOR FORWARD TRAVEL if the drive wheels are in the rear. I say this
because the drive wheels cannot push the track, only PULL it. (Is that
comment clear?) Anyway, does anyone have anything to say about this
topic?
----- Original Message -----
Sent: Thursday, October 12, 2006 5:52 PM
Subject: Re: M41 spring test video [TANKS] Good job George.
it hops over the logs smoothly and gracefully and bounces
still on its tracks! perfect stunts! mine falls like a safe or a trunk
on wheels.
Have you seen this footage with tests on T34s? They
run over logs placed vertically, yes, upright!!! not a good
idea...
And, what kind of battery do you use? size that fits
in your hull , Amp and dimensions please? I am curious because my tank is same
size as yours. I am using gel batteries, 12 and 6 Volts, 6 Amps.
one more question: why don't I see antennas in any of the
RC tank forum tanks? That's because the transmittors are always close to the
vehicle when you battle? I prefer my son to drive the tank away from us while I
watch with binoculars and report on obstacles. It;s like watching a movie or a
real battlefield.
CHrys
Nice day in Melbourne today, thought it was time for a
test drive so placed
some square wooden posts down and drove over them to see how the springs behave. Its not really finished and the batteries and stuff where not secured at all so had to behave a bit but still. Running over the posts looks a bit ugly but it was just for a test to shock it a bit, next video will be much better. Feeling that there is too much tension in the springs, doubt there even hitting the arm bumpers. Any comments welcome regarding how a tank would bounce, guessing it needs more dampening but will do some more tests soon, that is not its final speed either and also have to think about the weight of the turret. http://www.youtube.com/watch?v=IRsqnEJOhQ0 And yes I should have cut the grass. George |
