Subject:
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8475
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Newsgroups:
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lugnet.technic
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Date:
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Thu, 11 Jul 2002 02:05:24 GMT
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Viewed:
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4089 times
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8475 RC Race Buggy – A quick initial review
This is a 27 MHz remote control vehicle set. It isn’t called Technic, but it
is primarily composed of Technic parts, some new, at least to me.
The transmitter has two thumb control joy sticks, one up/down for motor
control and one side to side for steering. There are two auxiliary finger
paddles. It is 27 MHz based device which takes a standard small 9v “radio”
battery. There is a three position channel switch - more later on what this
does.
The receiver looks like the back half of a F1 or Indy style car. It sports
two 2x2 stud power connectors and has a built in steering servo with a cross
axle hole at the front to connect to the steering gear. It uses 6 x AA
battteries, so the assumption is that it is a 9 volt system.
It has rather too few mechanical connection points for my liking, making it
difficult to attach custom body work.
The interesting thing is that it relies on external motors for tractive
power. And yes – I did say motors. They are a new (to me) 9 volt motors with
built in gear reduction.in an odd enlongated package. One attaches to each
side of the rear of the receiver unit and is hinged to form part of the rear
suspension. By providing individual motor drive to each rear wheel, the
designer has avoided the issues of supplying a high torque differential.
I tested the motors running from an RCX. They work. I tested Mindstorms
motors running from the receiver module – they work too. The new motors
take ten times as much current as the Mindstorms ones do, as measured off
load at 9 volts. They are geared but to a higher final speed of 1200 rpm at
9 volts at 200mA. (Typical Mindstorms motors run 360 rpm at 9 volts at 20
mA.) There are both forward and reverse power takeoffs for application
generality.
The remote control does NOT work like a conventional 27 MHz R/C system. The
communication protocol works in a similar manner to the IR remotes used by
Bionicle Manas and 4589 RC Nitro Flash. The 27 MHz carrier is pulsed in a
short burst encoding the settings of the two joysticks and the finger
paddles. The bursts contain different address bits and have different
repetition rates depending on the channel chosen, so the main carrier
frequency of 27.145 MHz is the same for all channel settings. The
transmitted data bits use the pulse length scheme rather than the standard
async serial data standard used by Manas and Nitro Flash.
Control is pseudo proportional, there are three “values” in each direction
for the steering and three speeds in forward and reverse for power.
The standard Mindstorms type wires used to connect the drive motors connect
to the receviers main power port (2 x 2 electric plate). There is an
auxiliary port which can be used to drive “something else” like another
motor or lights or something. The two finger paddles operate this output
making it active in either forward or reverse depending upon the paddle pressed.
The steering output is connected via a cross axle to a one piece rack and
pinion unit. (I suspect this is to hold the rack system together under
impact else it would keep popping apart and severly limit “playability”. But
it does interface to the front wheel steering knuckles via standard Technic
parts. I “hit the wall” a few times while adjusting to the steering control
and nothing broke or popped undone. I consider that a good property for a
model which is essentially held together by friction.
Both the transmission and steering have been well designed to permit full
customization using “off the shelf” or is that “out of the box” Technic
parts and techniques.
Overall review.
As an R/C toy.
Fun. It has some zip and I think it would form the basis of some great
models. Its nice to have a proportional steering system which attaches to
Technic parts. (I’m going to have to think hard about the ramifications of
this option ;)
As an add-on for the big Lego collection.
Fun. I think this may provide a seriously overdue capability which will
empower Lego purists with an option which they have not had access to
previously.
Overall impression. Great. Seems expensive, but then good Lego sets always
do. A must if you are into Technic and need RC. As soon as they’ve been
around for a while and start showing up on discount, I will buy a bunch! For
now, I’ll continue to exercise the cat from which I got a thumbs (?) up.
JB
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Message has 4 Replies:
 | | Re: 8475
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| (...) [snip] (...) Wow! this sounds like it might be pretty useful! Those motors sound interesting...plenty of scope for breaking gears... Any info on the full throw of the proportional output? Thanks for the review! ROSCO (22 years ago, 11-Jul-02, to lugnet.technic)
| | | Re: 8475
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| I have to say -surprisingly, this looks like maybe TLC is getting more on track. This set seems to have much more potential than I expected. Not being able to pry this away from my 10 year old who was busily building, I had to wait until he went to (...) (22 years ago, 13-Aug-02, to lugnet.technic)
| | | Re: 8475
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| (...) I just want to add that I've only seen two of these, and they both had a minute problem with centering the steering. A full proportional system has a trim setting on the transmitter, since the signal is constantly sent all the time the (...) (22 years ago, 22-Aug-02, to lugnet.technic)
| | | Re: 8475
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| They are geared but to a higher final speed of 1200 rpm at (...) Does anyone know how much touque these motors have (from the drive hole thingy) in n/m. Mindstorms motors produce about 8.9 n/m and 8720 motors produce about 1 n/m but spins at about (...) (22 years ago, 25-Aug-02, to lugnet.technic)
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