Subject:
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Re: Feedback requested on an MOC chassis
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Newsgroups:
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lugnet.technic
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Date:
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Sun, 20 Jan 2002 06:08:24 GMT
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792 times
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I wrote up a few notes on the model and images; nothing very detailed, but
it should give some more information than what the pictures show. I also
uploaded a few other images onto Brickshelf that I had taken the following day.
By the way, those wheels at the bottom that you mentioned are actually the
ends of the stabilizers. ;-)
Model information:
Model name: Airtech Claw Rig: Second Generation
General description: Basically an 8868 ATC Rig on steroids; the "highlight"
functionality of the unit is the same but it is larger and has a few
additional extras
Primary colors: Mostly black with red trimming, lots of gray as well used
for the inner assemblies
Completion status: Unfinished (the images posted here are only those of the
chassis), maybe about 60% complete
Sets used:
I can't really remember all of the official models I used to make this, but
most of the elements are from the following sets:
8064 Universal Motor Set
8082 Universal Multi-Control Set
8459 Pneumatic Front-End Loader
8462 Super Tow Truck
8480 Space Shuttle
8485 Control Center II
8857 Street Shopper
8865 Auto Chassis
8868 Airtech Claw Rig
8880 Super Car
There are a few additional bits that I obtained independently of any set
(such as the lights in the front), but almost everything otherwise is from
the sets mentioned above.
Image descriptions:
atcr2-01: General side view of the unfinished Airtech Claw Rig: Second
Generation model.
atcr2-02: Another side view of the chassis. This was taken in the daytime as
opposed to a lighted room in the night, so the colors look slightly different.
atcr2-03: Top view. The "guts" of the model can mostly be seen from here,
although it is probably too blurry to make out anything (lol I really need a
better camera)
atcr2-04: Bottom view. The bottoms of the battery boxes (yellow) can be seen
from here. The two pneumatic compressor pumps are the small yellow things
just beside the battery boxes. The four gray wheels facing downward are from
the 8064 set and are actually the bottoms of the stabilizers.
atcr2-05: Rear view. Not much of significance here, but a careful look at
the image will reveal two rows of red lights (four each) near the bottom.
atcr2-06: Another rear view of the model, although this one is more of a
perspective view and shows the side and top as well.
atcr2-07: Front view. The license plate is obviously from the 8462 model,
and there are some small lights similar to the ones in the back. The two
large lights at the top are capable of lighting up.
atcr2-08: A more close-up top view showing some of the gears.
atcr2-09: Several of the gear trains can be seen here. There are numerous 16
and 24 tooth gears at the left of the pictures; these make up the two gear
trains for the V-10 engines. (not yet attached to the model) The two worm
gears near the bottom right corner are part of the motor-stabilizer gear
train. The tops of the battery boxes are also readily visible.
atcr2-10: Another view of the gears in the middle, this time shown from behind.
atcr2-11: This image shows the area just in front of the two worm gears seen
in image 9. The two differentials function as normal gears here (they are
connected to the steering rack), and I only used them because I needed a
precise gear ratio that the other gears could not provide. (see notes on the
steering mechanism for more information) The three bevel gears inside each
differential only serve to connect it firmly to the axle that runs through
it. The gears on the far right are parts of the main drivetrain and go down
to connect to the front differential.
atcr2-12: A zoomed-in view of the engine gears referred to in image 9. Some
of the dark gray 16-tooth gears can be seen in the back, which allow three
or four independent geartrains to cross through each other.
atcr2-13: This photograph shows some gears in the middle of the truck that
are part of the steering system. The differential gear is used like one of
the gray conical gears here and is not connected to the axle that passes
through it. (the axle is part of the system that connects the drive
differentials together)
atcr2-14: Another close-up image, showing some parts of the
transmission-style switching system. (to allow the motors to operate either
the compressors or the stabilizers) If you look closely, the transmission
driving ring can be seen below the two axles with the dark gray 16-tooth
gears on either side of it. The liftarm at the bottom of the picture is
connected directly to the switch used to push the driving ring around. (I'm
planning to attach a flex cable here that will lead to a manual switch on
the outside of the model)
atcr2-15: This is a view from the bottom of the truck. The two motors can be
seen here; they both directly power the black worm gear between them, which
attaches to a 24-tooth gear, which in turn leads to the transmission switch.
The pneumatic pumps and the cams used to turn them (or rather, pulleys
acting as cams) are at the right corners of the photograph.
atcr2-16: A very close-up picture of the transmission switch seen in the
last two images. The "switcher" on the side of the driving ring is on the
same axle as the liftarm seen in image 14.
atcr2-17: Another close-up view, this time of some of the gear assemblies
used for speeding down the gear train for the stabilizers.
atcr2-18: This image shows pretty much the same assembly as in image 17, but
a second worm gear can be seen under the axle.
atcr2-19: Yet another photograph of the stabilizer drivetrain. This is near
the back of the truck and one of the two worm gears used for the rear
stabilizers can be seen in the corner.
atcr2-20: Close-up of the gears in the front of the model (seen in image
11), part of the main drivetrain. The 24-tooth gear leads down to a series
of other gears, ending with the front differential gear. The crown gear is
attached to an axle that goes to the center wheel's differential area.
atcr2-21: Suspension system on one of the front wheels. Two of the large
dark gray shock absorbers from 8880 have been used, along with two small
light gray ones and a single small dark gray in the middle.
atcr2-22: Same thing as the last image but with the wheel removed for a
better look at the suspension linkages. Not too different from the system
used on the 8880 Super Car.
atcr2-23: This image shows the shock absorbers for the rear wheels. Notice
that these have fewer shocks than the ones in the front; the slight
asymmetry in the suspension compensates for the fact that there are four
wheels here instead of two.
atcr2-24: This is a zoomed-in view of one of the lights in the front of the
truck. The yellow transparent piece is from 8462 and contains two of the
small "Light and Sound" lights.
atcr2-25: An image of the claw arm, or whatever of it is finished. The final
unit will have three moveable sections on the turntable (the first of which
uses two pistons, as can be seen here) and a claw at the end. I will
probably try to implement a "four-finger" claw into it if I can come up with
a design that isn't too large. Two 6x2x2 weight bricks just behind the
Technic logo help to even out the weight.
atcr2-26: The two V-10 engines. One of these will be connected to the main
drivetrain (differentials) while the other will go to the motors
Some other general notes on the model:
The system used for steering/drive is pretty much the same thing as that of
the 8880 Super Car, utilizing the same specialized pieces. The central set
of wheels is not steered and therefore uses a slightly different assembly,
somewhat similar to the one used on the rear wheels of the 8865 model. (less
bulky though) The two steering racks are joined together by two really long
axles (smaller axles joined together by axle connectors) that have different
sizes of gears at their ends. I calculated the difference between the front
and center wheels to be about 3.5 times the distance between the rear and
center wheels, so the gearing has been done with a 3.5:1 ratio. I used the
small 8-tooth gears for the rear steering rack, and decided to use the old
1980-1993 differential gears (28-tooth) for the front rack, thus making the
speed difference exactly equal to 3.5. (image 11 shows the rack-and-pinion
assembly for the front wheels)
The model is quite heavy (and will become even heavier when completed), so I
really had to gear down the stabilizers a lot to allow them to lift up the
model. The path from the two motors to the actual stabilizers is an
incredible 1:20736, with three worm/24-tooth connections and a single
16/24-tooth connection. They take an extremely long time to fully extend or
retract (over one minute), but they are able to lift the truck up quite
well. Each stabilizer is pretty much a larger version of the standard ones
found on sets like 8854 or 8460 and works similarly. The main difference is
that the two "arms" used to attach the stabilizer to the truck are the same
distance away from the stabilizer, so the stabilizer itself goes straight up
and down rather than tilting at an angle as in the official Lego models.
I ran into a bit of a problem when trying to decide where to place the power
sources for the motors. The model is quite tightly packed with
interconnecting gear-trains and there was no room left for the battery box,
except for two spaces on the sides of the model and a small enclave in the
very front. I wanted to place it somewhere near the rear and central wheels
instead of the front ones since the combined suspension of four wheels would
be able to better withstand the added weight, but there was no real room
there. The areas on the side worked well, but they were at the very edge of
the model and if I only filled up one space and left the other empty, the
weight distrubution would have become quite unbalanced. (tilting the truck
to the side) The space at the front would have put all of weight of the
battery box on the front wheels, so that was also not a good idea. I was at
one point considering attaching the thing to a Control Center but decided
against it since it would be kind of annoying to have the truck tied up to a
stationery unit, limiting its movement capabilities. I finally ended up
dropping in two battery boxes (instead of just one) into the two open slots
on the sides to even out the weight; one battery box might not be able to
operate all of the lights and stuff anyway, so it might have been necessary
to put in two of them anyway.
-Gaurav Thakur
cp5670@home.com
http://cp5670.250x.com/TC/
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Message has 1 Reply:
 | | Re: Feedback requested on an MOC chassis
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| Thanks for the detailed writing. Your MOC is really impressive. You have done some amazing engineering to place all that functionality into such a limited space. I truly admire the work you have done. -- Bob Fay THE SHOP (URL) Thakur" (...) (23 years ago, 20-Jan-02, to lugnet.technic)
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Message is in Reply To:
| | Re: Feedback requested on an MOC chassis
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| Looks like you have more gears than I have. You have sure packed a lot of mechanics into a small space. I am not sure what is going on in that chassis, but it is really interesting. I hope to see your description soon. First question I have is: What (...) (23 years ago, 18-Jan-02, to lugnet.technic)
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