From: hutto@SMTC.engr.scarolina.edu (Brent Hutto)
Subject: OK, now I've got this RC10L, now what?
Reply-To: hutto@smtc.engr.scarolina.edu
Organization: NIST Southeast Manufacturing Technology Center
Date: Thu, 10 Sep 92 17:49:38 GMT

Here's the deal.  I've been racing off-road for almost 2 years, but last
Sunday I raced a (borrowed) pan car for the first time ever.  It was on
a carpeted road course, about 220' center line, fairly tight layout, but
not really very difficult.  OK, now I'm hooked, so I proceded to buy the
following items:

     Associated RC10L Fiberglass kit
     Andy's Lotec GTP body
     Bolink threaded front axles
     Parma Teflon damper disks
     Pure-Tech battery straps (3+3 "thin" style)
     A can of Paragon "Tire Stink", er, I mean "Traction Compound"

Captured from some other vehicles is the following equipment:

     Several 6-cell saddle (3+3) packs of 1400SCR cells
     Reedy 14-turn double modified motor
     Novak 410-M5 ESC
     Novak mini-receiver
     Airtronics 94143 servo (rated at 0.09 sec / 32.5 oz-in, ball-bearings)
     Titanium turnbuckles for steering tie-rods

So far, I've garnered the following advice, mostly via E-mail from Andrew
Zimmerman (thanks, Andrew!).
     1) when the stock graphite axle breaks (and it will) get a T&A-brand
        titanium axle, the solid one is OK, the hollow one is lighter but
        more expensive;
     2) the stock hubs are OK, just use Loctite and put a flat spot on the
        axle where the set screw bears down;
     3) get a 48-pitch or 64-pitch spur gear, the Losi 64-pitch ones last
        longer and are cheaper than the Magic Motor Sports ones;
     4) hardened steel diff balls work fine, just replace them as needed,
        "Gator Balls" brand ones are inexpensive in packs of 50;
     5) Parma/PSE threaded front axles are better than Bolink, but the
        Bolink ones are OK;
     6) use either toe-in or toe-out on the front, a neutral setting makes
        the car wander on the straight; and
     7) dial in a little brake at throttle neutral to help in the approach
        to the turns.

I have several questions listed here.  Keep in mind that the context I'm
interested in is racing an RC10L on a flat carpet road course with modified
motors and 6-cell batteries (no 1700mah cells). Anything specific to ovals
or stock motors isn't particularly relevent, although feel free to post it
if you think it is interesting.  I don't know enough about on-road to know
if asphault or concrete advice applies to carpet or not.  As a matter of
fact, I'd love to hear other people's experience on both pavement and carpet
so as to compare the two surfaces as for their effect on racing.

QUESTION: How do I use the Parma Teflon damper disks?  I've seen them
mentioned in magazine articles about the '10L, but I'm not sure what they
do.  I tried replacing the white friction damper disks above and below the
rear upper brace with them, but they didn't seem to be as smooth as the
stock white plastic things.  Did I leave out something?  Do I put them in
along with the white plastic ones?  Did I waste the $2.50 I spent on the
Teflon ones?  And yes, I did sand the upper brace really smooth where it
slides on the dampers.

QUESTION: For racing on a carpet road-course, do I want a little bit of
"Ackerman steering" or a lot?  I think I can vary it slightly by moving the
servo fore and aft to vary the angles of the steering tie rods.  The way I
have it now (with the tie rods exactly parallel to the front bumper), it
seems to have quite a bit of Ackerman.  Is this good?  What I need for this
road course is lots and lots of low-speed steering, under both power-on and
power-off conditions.  High-speed performance isn't as much of an issue
since I don't spend much time at high speeds on this road course and I don't
do oval.

QUESTION: What is the largest spur gear that will fit on a stock RC10L?
It looks to me like anything much over 84 or 86 teeth will make the bottom
of the spur extend past the bottom of the rear pod.  On a really smooth
carpet course, this shouldn't hurt anything except when you drive over 
something laying on the track or if another car "submarines" you from the
rear (which does happen sometimes on our track).

QUESTION: What are the relative advantages and disadvantages of the various
styles of bodies: GTP, TOJ, Indy-car and NASCAR on a carpet road course?
It seems to me from watching one race that the NASCAR bodies are at such a
disadvantage that you would only run them if you were in a race where everyone
agreed to use NASCAR bodies.  If anyone else runs GTP, TOJ or Indy-car bodies,
you would have a hard time being competative running a NASCAR one.  When I
compare GTP bodies to Indy-car bodies, it looks like the Indy-car bodies are
more maneuverable in the twisty parts and lighter, too.  The GTP bodies really
nail the car down on the fast parts and provide more high-speed steering, but
that steering seems to come in great gobs at a time whereas the steering with
the Indy-car bodies seems to be "just as much as you need right when you need
it" like with the Indy-car bodies.  All of this may just be an effect of the
particular cars I watched at this one race. I haven't seen a TOJ body run yet,
they seem a bit out-of-fashion.

QUESTION: How much caster is built-in to the RC10L as it comes in the kit?
How do you adjust the caster to other values?  Is the amount that comes with
the kit appropriate for road-course racing?  I think I understand how to put
in camber with the adjustment shims provided with the kit.  Am I correct in
thinking that no camber (i.e., no shims) will work fine to start with?

QUESTION: How about those stiff, graphite "roll-over" antenna tubes?  Is there
any benefit to using one of them?  They look neat, but I'd be afraid a turn
marshal would trip and impale an eyeball on one of them.

QUESTION: There are five cell slots on each side of my chassis.  All the
pictures I've seen show the rear-most three slots on each side in use. I have
and idea that I'd like the way the car handles better if I use the middle
three on each side or even the front-most three.  That should put more of the
weight on the front wheels and move the fore-and-aft location of the center of
mass toward the center of the car.  This should quicken up the response of the
car about the yaw axis, i.e., make it steer quicker and better.  Has anyone
tried other than the rear-most slots?

That's enough questions for now.  Any and all replies are appreciated to any
or all of these questions.  Once I get the body done and the car on the track,
I may post a few observations and any additional questions that occur to me
while I'm testing.
-------------------------------
Brent Hutto
hutto@SMTC.engr.scarolina.edu
Newsgroups: rec.models.rc