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| Type: |
Valentine Mk IV |
Armament: |
40mm |
| Built: |
October 2004 |
Armor: |
65mm |
| Builder: |
Jon Kowitz |
Rating: |
30/3 |
| Status: |
Under Construction |
Battles: |
0 |
| Owner: |
Jon Kowitz |
Points Earned: |
0 |
| Call Sign: |
Be Mine |
Points Given: |
0 |
| Notes: |
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1/4" plywood body on a 3/4" box steel frame Replicated Vickers "Slow-motion" suspension system FWW motor system (aka: Ford windshield wiper motors) Lightweight TTS with plywood drive sprocket Two-speed Tri-Pact speed control September 2005 or bust!!!
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Click Photo For Enlargement (47 Kb) |
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When I started this guy I was stuck with almost no money to do it with and
a pretty limited selection of motors to do it with. This steel frame will
carry all of the vehicle's weight and motor torque so I can hopefully
lighten up the rest of the hull considerably to save weight. We'll see how
it turns out.
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The Valentine's suspension system was called a "Slow Motion" type when
patented by the Vickers corporation. I figured that this is probably as
good a replica as any and should be solid enough to withstand any kind of
forces that this machine can generate, yet still allow the roadwheels to
articulate to accomodate any terrain it's rolling over to maintain traction.
A good example of loss of traction is in the video archives where the
Hetzer gets one corner up on a rock which leaves very little of the track in
contact with the ground. We'll see how well it works.
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Click Photo For Enlargement (48 Kb) |
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Click Photo For Enlargement (128 Kb) |
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Here's the jig I made to cut out the roadwheels and belt pulleys for the
project. Keeps my fingers well away from that saw blade which suits me just
fine.
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Coming along, we now have all of the roadwheels installed and the
motor/transmission box partially assembled. It was at this point that all of
my friends started taking the project seriously. The track tensioners are
spring loaded which should (in theory) maintain proper track tension
regardless of what the suspension is doing.
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Click Photo For Enlargement (121 Kb) |
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Click Photo For Enlargement (61 Kb) |
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Another shot of the "Slow-motion" suspension with the roadwheels
installed. The Val uses two rows of track guideteeth to hold the track
under the suspension so only one wheel is installed on each axle instead of
the usual two.
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One good look at my motors and you should realize why I'm weight paranoid
with this project. These are late model Ford windshield wiper motors,
selected because they are cheap, are readily available, and can be found in
a wide variety of Ford automobiles and trucks. One of the biggest drawbacks
so far will be speed. Motor shaft RPMs are a paltry 120 RPM which will
make this a slow beast no matter what I do. Over-volting may be my only
option eventually but we'll stick with a safe, 12v system for now.
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Click Photo For Enlargement (122 Kb) |
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Click Photo For Enlargement (76 Kb) |
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The difference three weeks can make. Tracks are on, electronics wired in,
and the rest of the drivetrain assembled. As you can see by the battered
trackpads I've already had a bit of fun with the beastie. Top speed is a
modest 3-4 mph (about the speed of a brisk walk), which gives it a scaled
speed of 18 - 24 MPH, which beats the full size version's 15 MPH pace anyway
(lol). My track tensioning system isn't working out, allowing the track to
jump on the sprocket when under duress (aka: trying to turn in grass) so I'm
thinking about replacing the springs with a turnbuckle which will hold the
tension a bit better (I hope anyway).
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As a bad housekeeper says, pardon my mess (lol). Most of the electronics
are going up in the turret (which obviously isn't assembled yet) so it kinda
got piled on the bellypan somewhat haphazardly. The single 12v, 15 AH
motorcycle battery sits up front and is secured by the cargostrap located
there. Although it sounds small (and it is) my tiny motors actually pay off
somewhat. That tiny battery powers the beastie for about 90 minutes of
brush-thumping, stump-climbing fun.
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Click Photo For Enlargement (137 Kb) |
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Click Photo For Enlargement (99 Kb) |
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I personally never thought that I'd be able to cut a workable sproket out
of a sheet of plywood, by hand, and have it work at all, let alone as well
as these work. The second one I made does work a bit better than the first,
but both hold onto the track quite solidly. Only times it jumps is when the
tensioner gets pulled back, slackening the top part of the track. That'll
be worked out soon enough. Unfortunately I don't have any pics of the track
being assembled but it's made from two, 1" nylon straps like is used for a
dog leash and 3/4" wide strips of 1/4" poplar wood. All glued (shoo goo of
all things) and braded together into a fairly resiliant track. I've lost a
few guideteeth from thrown tracks but those don't seem to be effecting
performance any.
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