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Top Fuel Cars - Two-Wheeled Pinewood Derby Cars Revisited

(The ninth in a series of articles on cars that "stretch the rules")

In 2008 I published an article on a two-wheeled car, running on
diagonally opposite wheels. (see Pinewood Derby Times - Volume 7,
Issue 14

I raced a car built using this technique in an Outlaw race in April
2008. The car did well, but due to the center weighting scheme, it
didn't take first place.

Two-wheeled Outlaw Car

Later, a customer, Bob Wheeler, came in to the shop with his version
of a two wheeled car. Modeled after a car that was entered at his
pack's race many years ago, it runs on the right-front, and left-rear
wheels; the other wheels are off the ground. Unlike my car which is
center-weighted, Bob's car is rear weighted (balance point at 1-3/4
inch in front of the rear axle) by offsetting an underbody lead plate
to the left. It is possible that this design could be made faster by
using tungsten plates and shifting them further back. Nevertheless,
the car is very fast; it has taken first in several races.

Top of Bob Wheeler's Car

Bottom of Bob Wheeler's Car

I was ready to let the idea of a two-wheeled car go into oblivion,
until I ran across a car by Joe Tomelleri on the Derby Talk forum.

Joe Tomelleri's Car
Source: www.americanfishes.com/2wheelerB.jpg

Joe's car runs on two single file wheels. With rail-rider alignment,
only the front wheel touches. This car was intriguing to me, so I
decided to build a variation of Joe's design.

On my design, I discarded the other two wheels, and replaced them with
outrigger bars, tipped with small beads. The weight is tungsten (just
over 4 ounces) and the wheels are light weight H-Tread wheels. The
alignment is set to rail ride. Admittedly the car could be made more
elegant by hiding the weight and giving it a nice paint job, but I
kind of liked the functional look.

Two-Wheeled Car - Right Side View

Two-Wheeled Car - Left Side View

On the track, the car ran very smoothly. It turned out that the
outriggers were not needed, because as soon as the car reached the
braking section, the car flopped over onto its right side. When raced
against my other two wheeled car (first photo), this new car wins by a
car length.

Flush with success, I decided to remove the outriggers, improve the
looks of the car (a little), and improve the speed with the
introduction of Super Stock Needle Axle Wheels (SSN) from DerbyWorx.

Updated Two-Wheeled Car

I plan to run the car in the Outlaw Division of this year's race on
April 15. I'm sure it will create quite a stir, and I'll let you know
the results in a newsletter in October.

If you implement a two-wheeled car, please send me a photo and a
description, and I'll be glad to include it in a future newsletter.

From Pinewood Derby Times Volume 10, Issue 14

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