My fiancee Mark is an old hand at derby cars.... I'll hand the keyboard over
to him:
When I worked at TWA lo these many years ago, we had a Pinewood Derby
Invitational. It started out as a way of letting the fathers play without
interferring with the kids doing their own cars. Over the years it turned
into a highly competitive event with substantial cash prizes. We had
engineers from McDonnel Douglas' fighter department and such.
Wheels : I have been known to chuck them into a unimat and true up the
diameters to within .001in. If the rules allow, reprofile the tread surface
to a taper (like this :\_/ )
to reduce the rolling friction. Small footprint equals lower rolling
resistance.
Axels: If the rules allow, replace them with turned steel or brass pegs.
Match the axels to the wheels, as the nails provided get too small once
you've removed the nasty seam onthe side from where they were hot stamped.
NOTE: Most rules won't let you fit any sort of bearing. check carefully -
otherwise a short length of brass tubing set into the wheels will give you a
serious advantage (We had an unlimited class where the only restriction was
total weight some guys went to fars as to fit tiny roller bearings)
Lubricants : light oil for electronics is one of the best bets as it won't
adversely affect the plastic wheels and isn't too thick
The final speed secret is the easiest. No matter how much effort goes
intothe wheels and axels, almost no one ever gets them completely broken in.
Run (roll?) the car as much as humanly possible before the race to break
everything in. Our most consistant winner was a boy scout leader who was
keeper of his troops track, and so ran his cars a lot during construction.
His cars were looser than everyone else and ran much better (much to the
chagrin of the rollerbearing bearing engineer<G>)
Mark not
Laurie :-)
70 SPL311
AzROC
Chandler, AZ
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