[TANKS] Warthog all-terrain vehicle (ATV)

[Odyssey...@aol.com]

In a message dated 11/27/2009 5:55:51 A.M. Eastern Standard Time, callum.kin...@googlemail.com writes:

http://www.army-technology.com/projects/warthog-all-terrain/

i would think just build two powered units just like any other tank and just ball hitch them (somehow) together. make them skid steer just like a tank, but when both are coupled together, you'd have to be on the move to make any kind of turn or course correct.

 

Chris,
Odyssey Slipways

[Clark Ward Jr]

@Chris - I think you're right; If both halves were given a command to
skid-steer 45 degrees right, it wouldn't work, but if you set up the
controls such that a command to steer right in the front end is a
command to steer left in the back end, you could steer it while its in
motion, just no pivotting in place.

--
Clark in Georgia

[callum.kin...@googlemail.com]

A linear actuator may have enough torque to turn 2 halves. Or a
combination of multiple actuators???

[Frank Pittelli]

callum.kin...@googlemail.com wrote:
> A linear actuator may have enough torque to turn 2 halves. Or a
> combination of multiple actuators???

Sorry to burst any bubbles ... but I don't think the Warthog would ever
be an effective support vehicle in the hobby ... despite it's novel appeal.

Specifically, common skid-steering (forward on one track and reverse on
the other) will *NOT* work because as soon as you reverse one of the
tracks on the tractor or trailer, the pivot joint will lock over in one
direction and the vehicle will prevent itself from completing the turn.
That's how we originally tried to steer the Goer and it was an
immediate failure. Even though it used wheels instead of tracks and the
trailer wheels were free-wheeling, the lateral friction of the wheels
was enough to stop it dead in a turn.

The Goer and ZD3000 both use a modified skid-steer control (called
tractor steering) that simply cuts off power to the inside tractor wheel
when turning, allowing the inside wheel to free-wheel during the turn.
That allows the single outer wheel to turn the tractor and the
free-wheeling trailer follows it around the turn.

Unfortunately, I don't think such a modified skid-steer control will
work at all for the Warthog. Since a track has far greater rolling
resistance than a wheel, a single track on the tractor will not be able
to turn the tractor by itself, let alone with a tracked trailer behind
it. We've proven this many times on the battlefield when a tank track
stops working for some reason. In those cases, the tank continues to
move along with only a slight curve to it's direction. Basically, the
free-wheeling track acts like an outrigger, helping to keep the tank
going straight.

That eliminates both forms of skid-steering commonly used, so what's
left? The only approach I can think of that has any chance of working
is to use the same approach that the real vehicle uses: computer
controlled operation of all four tracks. Specifically, when you want to
turn the vehicle, the computer starts varying the relative speed of all
four tracks to (a) cause the tractor to go in a given direction and (b)
keep the tractor-trailer angle constant during the turn. This is *not*
as easy as it sounds, because the trailer has to start and stop turning
*after* the tractor does (so it will travel along the same path).
Moreover, the amount of time depends on the actual speeds of the vehicles.

As a veteran software developer, I wish "good luck" to anyone that
develops the required software. Even if they do get it working, the
resulting vehicle will under-perform all other support vehicle designs,
rendering such clever programming virtually worthless. Specifically, the
use of relative track speeds to turn the vehicle also means that the
turning-radius of the vehicle is significantly increased. Tanks have a
zero turning radius because of full skid steering. The Goer and ZD3000
have a slightly larger turning radius using tractor steering. Wheeled
vehicles using conventional steering have a greater turning radius,
limited by the angle of the steering wheels. By far, the worst turning
radius would be the Warthog.

When it comes to a tracked support vehicle, I think that the best (and
perhaps only) choice is the FV103 Spartan as evidenced by SV015 built by
Mike Mangus. With a zero turning radius, go-anywhere performance and
heavy-hauling capacity, I don't see any other vehicle matching it in the
support vehicle category ... including the venerable Goer and UN Peace
Keeper. It costs more to build and operate, but over time I think it
will prove to be the most effective support vehicle design. But, that's
just a personal observation based on a relatively small amount of design
and battlefield experience.

Frank "A high-speed Spartan would change the game" Pittelli

[callum.kin...@googlemail.com]

I do find myself agreeing with you but it would be damned cool to see
it done. One of my friends is considering making an RC car, Hasnt
decided on size but if it was built 1/6 it would be allowed seeming as
it is a military vehicle. Vehicle in question is a jackal. If it was
built as the mk19 version would it be allowed a paintball gun? mk19
could perhaps counts as a 40mm as that is what it fires.

On Nov 28, 4:44 pm, Frank Pittelli <frank.pitte...@gmail.com> wrote:

[Frank Pittelli]

callum.kin...@googlemail.com wrote:
> I do find myself agreeing with you but it would be damned cool to see
> it done. One of my friends is considering making an RC car, Hasnt
> decided on size but if it was built 1/6 it would be allowed seeming as
> it is a military vehicle. Vehicle in question is a jackal. If it was
> built as the mk19 version would it be allowed a paintball gun? mk19
> could perhaps counts as a 40mm as that is what it fires.

There's no stipulation on the size of the gun carried by armored cars,
they all get 20 shots. So, the Jackal MK19 would definitely qualify as
an Armored Car in the hobby if built to the 1:6 scale or 36" rule.

Frank P.

[Derek Engelhaupt]

Frank,

Don't forget, my M113 is a rolling chassis too....;)  It just doesn't have a designation yet.
With the move and getting my shop reset I haven't had the time to apply for it.

http://i154.photobucket.com/albums/s265/nitzerebbhead/M113A3/IM000003a.jpg

Derek
T065

When it comes to a tracked support vehicle, I think that the best (and
perhaps only) choice is the FV103 Spartan as evidenced by SV015 built by
Mike Mangus.  With a zero turning radius, go-anywhere performance and
heavy-hauling capacity, I don't see any other vehicle matching it in the
support vehicle category ... including the venerable Goer and UN Peace
Keeper.  It costs more to build and operate, but over time I think it
will prove to be the most effective support vehicle design.  But, that's
just a personal observation based on a relatively small amount of design
and battlefield experience.

       Frank "A high-speed Spartan would change the game" Pittelli

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[mac wynkoop]

Wouldn't it just be easier to vary the speeds of the tracks on the first module of the vehicle?  Just speculating... or is the whole conversation about how to make it skid steer?

[Odyssey...@aol.com]

In a message dated 11/28/2009 12:36:40 P.M. Eastern Standard Time, mac.w...@gmail.com writes:

Wouldn't it just be easier to vary the speeds of the tracks on the first module of the vehicle?  Just speculating... or is the whole conversation about how to make it skid steer?

i think you would have to make 3 speed adjustments

 

to make it turn to the left

 

you would need to slow the front left set of tracks

speed up the front right set of tracks

slow down both rear tracks

 

at least that's about how i would figure it would need to be to try to work

 

Chris,
Odyssey Slipways

[Frank Pittelli]

mac wynkoop wrote:
> Wouldn't it just be easier to vary the speeds of the tracks on the first
> module of the vehicle?

Your plan is to drag a tracked trailer around and hope that it turns
when the tractor turns? That will require a significant amount of power
in thick grass or rugged terrain. On such fields, any lateral movement
of an un-powered track will simply dig into the turf.

Frank P.

[Frank Pittelli]

Derek Engelhaupt wrote:
> Frank,
>
> Don't forget, my M113 is a rolling chassis too....;) It just doesn't
> have a designation yet.
> With the move and getting my shop reset I haven't had the time to apply
> for it.
>
> http://i154.photobucket.com/albums/s265/nitzerebbhead/M113A3/IM000003a.jpg

It's always the darn paperwork that's done last. Are you planning on
operating the M113 primarily as an Armored Car or Support Vehicle?

Frank P.

[Derek Engelhaupt]

The original plan was just to make it a supply vehicle, but the plan now is to build two
tops.  One would be the flat top supply vehicle top and the second would have the
FSV (fire support vehicle) top with a turret.  I picked up the FSV 1:35 model on Ebay to make
the build easier.  The biggest issue with the build right now is that the motors are
producing so much torque that they are causing the upper hull to separate a bit at the
corners where the front plate meets the sides of the hull.  I might rebuild the hull out of
PVC sheet since I am in the process of ordering some for my KV-2 build now that I know
the drivetrain is workable design.  Or I could find a way to add some bracing to the
existing hull, but due to the way I mounted the motors that might be difficult.

Derek
T065

--

[callum.kin...@googlemail.com]

Thought of one method to make a warthog ATV work. Just.
Overcomplicated though so perhaps not a good idea. Make fixed
suspension system and have one wheel on each track lower than the
others. This should have the effect of making the vehicle based on 4
wheels and still look like tracks. Overcomplicated and still quite
frankly rubbish performance. or you could go the whole way and make it
with wheels.

On Nov 29, 2:05 am, Derek Engelhaupt <tan...@gmail.com> wrote:
> The original plan was just to make it a supply vehicle, but the plan now is
> to build two
> tops.  One would be the flat top supply vehicle top and the second would
> have the
> FSV (fire support vehicle) top with a turret.  I picked up the FSV 1:35
> model on Ebay to make
> the build easier.  The biggest issue with the build right now is that the
> motors are
> producing so much torque that they are causing the upper hull to separate a
> bit at the
> corners where the front plate meets the sides of the hull.  I might rebuild
> the hull out of
> PVC sheet since I am in the process of ordering some for my KV-2 build now
> that I know
> the drivetrain is workable design.  Or I could find a way to add some
> bracing to the
> existing hull, but due to the way I mounted the motors that might be
> difficult.
>
> Derek
> T065
>

> On Sat, Nov 28, 2009 at 6:30 PM, Frank Pittelli <frank.pitte...@gmail.com>wrote:
>
>
>
> > Derek Engelhaupt wrote:
> > > Frank,
>
> > > Don't forget, my M113 is a rolling chassis too....;)  It just doesn't
> > > have a designation yet.
> > > With the move and getting my shop reset I haven't had the time to apply
> > > for it.
>

> >http://i154.photobucket.com/albums/s265/nitzerebbhead/M113A3/IM000003...