Conference vmszoo::rc

1112.0. "1/10 Scale Drag Racing" by NUTMEG::IBBETT (Born to hover) Mon Sep 25 1989 16:30

In addition to flying RC Copters over the last year or so, I have also been 
running 1/10 scale cars -- mostly indoor oval. Over the weekend I took the 
plunge into a new area, that of 1/10 scale Drag Racing. I haven't seen a note 
on this yet, so I figured I would start one in the hope that there might be 
other crazies out there trying it. I am very familiar with running an electric 
1/10 scale car, but I realize there are differences (and the associated hints 
and kinks) between oval and drag. I would appreciate any wisdom about such 
issues as setup, motors, organized meets, etc.

I always wanted to drive a Funny Car. I did race a Modified door slammer quite 
successfully for 4-5 years up at New England Dragway, and even spent an 
eventful and exciting year piloting a methanol dragster, but I could never 
figure how to own or drive a Funny. My new acquisition sorta fixes that, even 
if it is 1/10 scale and doesn't reek of Nitro fumes.

For those who may be interested, the kit I bought was the Lazer-Lite funny 
car, along with the optional slider clutch and 2-speed transmission. It's not 
a cheap kit ($450+ total), but it *is* very high quality. Standard parts 
include working/adjustable wheelie bars, aluminum 2-piece rear wheels with 
pre-trued foam tires (2.375" wide x 3" tall), 1-piece aluminum front wheels 
with foams (1.5" x .5"), graphite chassis, etc. The quality and fit of the 
parts is excellent, as are the illustrated instructions. I will be transferring 
the electrics/radio out of my other car (Futaba radio, Novak speed 
controller), and the car will shortly get a TOP-FUEL-2 (50,000 rpm) motor 
rotated by a 10-cell SCR pack. Maybe one day I'll move up to a Drag Zeta 
controller and 20 cells, but I need to learn to drive it first... :-)

I am preparing 2 bodies -- a Buick Reatta, to be painted and decal'd like 
Kenny Bernstein's Bud King, and an Olds Cutlass which will be a John 
Force/Castrol GTX replica. I have also designed a radio-deployed chute system 
to help the braking.

If anyone else is into going straight and fast, I'd love to share 
experiences...

Rgds, 'Jungle' Jim :-)

    I am looking for some radio/electronic design help. Given the size of
    this notesfile's readership, I figured someone might know something
    about designing electronic gizmos that receive their control info from
    the radio receiver. An example is an ESC (electronic speed control),
    except that what I need is an EBC (i.e. BRAKE control).
    
    The problem I have is when using my 2-speed transmission, any brake
    effect provided by the motor (via the ESC "brake") only works in HI
    gear (the LO gear spur being connected to the jack shaft via a 1-way
    clutch). Thus, when the jack shaft RPM drops as the car slows, the
    transmission eventually drops back into LO gear and braking is lost.
    
    I am trying to design the mechanics of a disc brake attached to the
    jack shaft (from an 1/8 scale design/kit), but it will need servo
    control to actuate the disc brake. I have a 3 channel TX and 4 channel
    RX, but the extra channel is currently operating the reverser.
    
    What I think I need is a gizmo that "detects" that the TX has put on
    the brakes and then sends control info to a servo to apply the disc
    brake. Trims would be useful too.
    
    Now some questions:
    
    1) The simplest approach I can see is to run a servo in parallel with
    my ESC. Tacky, it might work (?) but I don't like the idea.
    
    2) Better approach is the aluded-to gizmo. How would it detect the
    brakes were on? From the RX? From the motor leads via the ESC?
    
    3) Anyone ever designed such a beast?
    
    4) Could I induce anyone to try and design one? What reward or
    renumeration would you like??
    
    5) Could the design be extended to pop the chute also (under given
    conditions)???
    
    The gauntlet is thrown down. Or maybe it should be a fire-proof Nomex
    glove -- after all, its for a Funny Car :-)
    
    I would deeply appreciate any help. I enjoy scratch building mechanical
    parts and electronics, and can wield a soldering iron effectively...
    
    Rgds, 'Jungle' Jim.