...an (almost) alternate model for 8275
bulldozer. "Almost" because in addition to the
8275 set you need one more battery
box and RC
handset to control the second Killer Dozer.
Each player control a dozer, the purpose of the game is to
tip over the opponent. With the RC handset you control your
dozer to go straight forward, to turn in place backwards, and
to lift/lower the blade to raise your opponent. Each dozer is
set on a different channel, and of course it is forbidden to
switch your remote on your opponent channel!
And of course you can build and control up to four Killer
Dozers for more fun... if you have the parts!
Front right view. The front bumper
is used to provide a grip point rather than to protect
...and back right view. The aim is
to tip over the opponent, so the battery box is
placed high on purpose.
Detail of the ratchet mechanism.
Killer Dozer is powered by a Power Functions XL
motor. While going forward, the ratchet slips over
the gear under it so both tracks are moving. When
going backwards, the ratchet prevent that gear to
turn, so the white
clutch gear placed on one side slips. Only one
track is moving and the Killer Dozer turns on the
Detail of the lifting mechanism.
A Power Functions medium motor turns a lever that
lead the blade to raise/lower cyclically.
Bottom view. Movement from the XL
motor is transmitted to the right regular 24 tooth
gear and to the left clutch gear. The left axle
goes through the middle 20 tooth gear that can be
blocked by the ratchet.
the Killer Dozers fighting (3Mb, AVI, DivX 5 codec)
is the LDraw/MLCad file of the Killer Dozer.
and here high quality printable building
MPD file ready for LPub4
rendering is here
(unofficial parts are not embedded in this file).
one is scaled for LDGlite rendering, you have to scale assembly
and parts size down for LDView rendering.
is the BOM image.
Mai 2008 update:
After some time playing with Killer
dozers, I noticed that the angle gears that transmit
motion at the output of the XL motor grind and slip
more and more. If you have other parts than those
included in Bulldozer kit, I suggest you replace
them with knob
As these gears are larger you will
also have to replace the gear used for the ratchet
with a 16t gear.
And, last but not least, direction
of the tread links does matter! If they are oriented
in the wrong direction there is more friction and
the killer dozer doesn't perform well. Viewed from
top, the tread links must be oriented as the green
one shown below. And yes, the treads in my LDraw
model are backwards, but it's too much work to correct...