KubKar Design
The following specifies the design of KubKars, Pickup
Trucks, 18
Wheel Trucks and KubKar Race
Tracks as well as tips to improve a KubKar's performance.
INTRODUCTION
KubKar racing is a 30 year old tradition in the Scouting
movement. It allows Cubs the chance to design a vehicle starting from a block of wood,
carve or cut it into a desirable shape and then race it against other Cubs. Cubs learn how
to use woodworking tools and important aspects of woodshop safety while under the
supervision of leaders and adults. The work can qualify for badge requirements such are
the Tawny Star, the Carpenter Badge and the
Handicraft Badge. The Cubs take pride in their
efforts, and look forward with enthusiasm as they pit their car against others in their
pack or visiting packs. The following describes important aspects and standards in the
design of a KubKar. Leaders and Scouts can enter Pickup Trucks and 18 Wheel Trucks.
If you want you can download two Excel 2000 spreadsheets that
scores KubKar events using 1, 2 or 3
KubKar tracks, each with three lanes. Track up to 15 races overall (9 races
usually fills an afternoon); Email the webmaster for these spreadsheets.
- 1 track, 44 heats, up to 132 KubKars, up to 15 races
- 2 tracks, 22 heats. up
to 132 KubKars, up to 15 races
- 3 tracks, 14 heats, up
to 126 KubKars, up to 15 races
Includes
suggested elimination round, statistics calculation, registration and race forms.
A complete planning guide
for a KubKar event is also prepared showing:
- Event Information
- Participants
- Tasks to be filled by volunteers
- Equipment needed
- Proposed schedule for the day
- KubKar Challenge rules
- KubKars and trucks construction
specifications
- Restrictions
Another excellent KubKar planning link can be found at the US
Scouting Service Pinewood Site
General Rules: All cars must start by gravity from a
standstill, at the starting point. No pushing is allowed. To finish the car whose nose is
the first to cross the finish line is the winner. The race official will decide the
winner, and if the result is too close to call, a second race can be run. If any car
leaves the track the race can be restarted. If the same car leaves again, the car is
eliminated.
These are 25 things that
could happen at a KubKar Ralley.
KUBKAR
SPECIFICATIONS
WIDTH:
Overall width including wheels is not to exceed 7 centimeters or 2-3/4
inches. The minimum distance between the wheels is 4.5 cm or 1-3/4 inches.
WEIGHT:
Overall weight is not to exceed 142 grams or 5 ounces.
CLEARANCE:
Clearance between the chassis and the track should be 0.95 centimeters or
3/8ths of an inch.
Note: Click on the above
picture of the KubKar Design to see it clearer
RESTRICTIONS
Wheel Bearings, washers and bushings are prohibited. The car shall not ride
on springs. Details and attachments may be added providing they are securely fastened and
do not exceed the maximum length, width and weight specifications. The car must be
free-wheeling and may only be propelled by the force of gravity. KubKars are subject to
inspection by an official inspection committee to determine eligibility.
KUBKAR
BUILDING GUIDELINES
Mark your chosen design on the top and the sides of the block. Carefully
carve or cut to the desired shape. Sand smooth. Paint, stain and/or finish as desired,
preferably with water based treatments. Insert axle through the wheel and force into slots
provided. The wheels should spin freely. Racers may wish to lubricate axles and wheels
using (dry) powdered graphite.
PERFORMANCE
TIPS AND HELPFUL HINTS
To build a fast car, there are several important details to consider:
First and foremost, is the wheel alignment, which is
necessary to obtain a straight smooth run, thereby reducing wheel friction on the guide
track rails. Next in importance is reducing wheel and axle friction. This is accomplished
by applying a dry lube to the areas along the axle and wheel bearing points. Also you may
want to remove any burrs that might occur on the axle or wheel itself.
Apply several coats of sanding sealer, then sand entire car with a fine-grade sandpaper. Give the model at least two coats of fast-drying paint.
When the paint is completely dry, sand with a fine sandpaper, apply a final coat of paint and allow to dry thoroughly.
Rub entire Truck with a rubbing compound. Apply a coat of auto wax and rub to a high gloss finish.
One can carve out the inside of the KubKar and insert metal
washers or bolts to bring the weight of the car to its maximum. Some feel that if one
places the car weight to the end of the car, the stored potential energy in the race will
make a faster car.
Lubrication is the key in many designs. Powdered Graphite
is one type although there are many other liquid lubricants that may gain an advantage.
Do not use regular oil or silicon, since this may soften the plastic.
One can slightly file or bevel the bearing surface of the
wheel to reduce the amount of friction touching the car surface.. Check
if the axles have "spurs" near the axle head. Grind away the
"spur" metal.
It is strongly recommended that one refrain from using
weights which contain toxic levels of lead.
Details are important. Take into consideration the
following: 1) wheel alignment, 2) axle and wheel lubrication and honing, 3)
weight distribution, 4) car design, 5) a high gloss finish.
LIST OF
MATERIALS IN A KUBKAR KIT
1 Block of wood 17.8 cm (7 inches) long, 4.5 cm (1-3/4 inches) wide, 3.2 cm
(1-1/4 inches) high
- 5 Black plastic wheels, 3.2 cm (1-1/4 inches) in diameter
- 5 Steel pin axles
- 1 Decal sheet
- 1 KubKar designer ribbon
- 1 KubKar Kit instruction sheet
OPTIONS
AND ACCESSORIES
Check your local Scout Shop and/or the official Scouts Canada catalogue for
KubKar accessories and presentation items. Items include templates and decals, accelerator
and tubular weights, crests, pins and trophies
Ordering Kits
(Catalogue Number: Car: 71-100, Truck: 71-202):
Kits can be ordered from your local Scout Store or
by writing to:
Scouts Canada
Box 5151 Station LCD-Merivale
1345 Baseline road
Ottawa, Ontario, Canada, K2C 3G7
Tel: (613) 224-5131
Fax: (613) 224-6022
KubKar and
KubKar Race Track Photos by Stephen Braginetz of the
BeacoNorth District
KUBKAR RACE
TRACK
The length should be suitably long enough to allow the cars to accelerate and
maintain speed. Some cars start fast, others maintain speed better. The best cars do both.
The starting gate should be made so that all cars start at the same time. A lane strip is
used to force the cars to follow a set path down the track. Sufficient cushioning should
be placed at the end of the track to catch the cars and thus avoid damage.
For ruggedness, permanent joints should be glued with white
glue and screwed. All wooden components should be block sanded to remove any splinters
before assembly.
After cutting the four track sections, glue and nail a
strip of 1/2"x3/16" flat molding along the edges to protect both the track and
curious hands. The lane guides are the last parts to be assembled because all attachments,
supports and so on, should be under these rails. Make a jig to position the three rails
exactly, and measure from the same side of the sections at various points to ensure
perfect alignment.
The sections are held together with 3/4"x2"
hardwood cleats. They should be fastened under the outside lanes with glue and 1-1/2"
flat head screws. Two-inch stove bolts with butterfly nuts are best for connecting the
sections together. The two end sections should be mounted on 1"x2" runners to
provide clearance for the nuts, and a stable, flat base for the track. To ensure a smooth
and even race, sections must fit together with precision, Sand and shape the interfacing
parts to eliminate any mid-run bumps.
The curved sweep on the ramp bends naturally into a smooth
starting ramp. It will probably be necessary to weight the short legs with a bag of sand
to keep the track on the floor. Paint the track with either a urethane varnish or a high
gloss enamel.
KUBKAR RACE
TRACK SPECIFICATIONS
List of Materials:
- Part P1 Quantity 1 Size: 4'x8'x1/2" plywood track sections
- Part P2 Quantity 1 Size: 2'x8'x1/4" plywood
- Part P3 Quantity 12 Size 8'x1/4x1-5/8" lattice
- Part P4 Quantity 6 Size: 3/4"x2"x1' hardwood
cleats to join sections
- Part P5 Quantity 1 Size: 1"x3"x8' pine long legs
cut in two
- Part P6 Quantity 1 Size: 1"x3"x3" pine short legs
cut in 3
- Part P7 Quantity 1 Size: 1"x3"x5' pine brace
(3x12") and stabilizer (1x3")
- Part P8 Quantity 1 Size: 1"x2"x6" pine brace
- Part P9 Quantity 1 Size: 1'x1/4" dowel starter post
rods cut in 3
- Part P10 Quantity 1 Size: 1"x2"x18" pine
starter bar
- Part P11 Quantity 1 6"x1/2" dowel starter handle
- Quantity 7 2" hinges
- Quantity 14 2"x1/4" lag bolt for cleats
- Quantity 12 1" #10 F.H. screws for cleats
- Quantity 14 1/4" wing nuts
- Quantity 14 1/2" washers
- Quantity 1 Heavy rubber band
- Quantity 18 1-1/4" #10 F.H. wood screws
- Quantity 1 Box 1/2" brads
- Quantity 4 pints of white paint
- Quantity 1/2 pint varethane
Note: Click on the above
picture of the KubKar Track Design to see it clearer
PICKUP TRUCK SPECIFICATIONS
WIDTH:
Overall width including wheels is not to exceed 7 centimeters or 2-3/4
inches. The minimum distance between the wheels is 4.5 cm or 1-3/4 inches.
WEIGHT:
Overall weight is not to exceed 142 grams or 5 ounces.
CLEARANCE:
Clearance between the chassis and the track should be 0.95 centimeters or
3/8ths of an inch.
18
WHEELER TRUCK SPECIFICATIONS
WIDTH:
Truck Cab:
Overall width including wheels is not to exceed
8.6 centimeters or
3 3/4 inches.
Truck Trailer: Overall width including wheels is not to exceed
9.5 centimeters or
3 3/8 inches.
The minimum distance between the wheels is 4.5 cm or 1-3/4 inches.
WEIGHT:
Truck Cab: Overall weight is not to exceed 255 grams or
9 ounces.
Truck Trailer: Overall weight is not to exceed
450 grams or 16 ounces.
CLEARANCE:
Clearance between the chassis and the track should be 0.95 centimeters or
3/8ths of an inch.
Note: Click on the above
picture of the Truck Design to see it clearer
LIST
OF MATERIALS IN A TRUCK KIT
Truck Cab:
1 Block of wood 7.6 cm (3 inches) long, 4.5 cm (1-3/4 inches) wide, 5.1 cm
(2 inches) high
Truck Trailer: Masonite wood panels forming a 6
sided box 30.5 cm (12 inches) long, 8.5 cm (3-3/8 inches) wide, 8.5 cm (3-3/8
inches) high
Truck Cab Wheel Base: 1 Block of wood
17.8 cm (7 inches) long, 4.5 cm (1-3/4 inches) wide, 1.9 cm (3/4 inches) high
Truck Trailer Wheel Base:
1 Block of wood 8.9 cm (3-1/2 inches) long, 4.4 cm (1-3/4 inches) wide,
1.9 cm (3/4 inches) high
- 18 Black plastic wheels, 3.2 cm (1-1/4 inches) in diameter
- 10 Steel pin axles (2 on cab front, 4 on cab
rear, 4 on trailer rear)
- 2 Dowels for smokestack
- 1 Centre Pin
SPECIFICATION
SUMMARY
| |
KubKar/Pickup
Truck |
Truck Cab |
18
Wheel Truck Trailer |
| Maximum Weight |
142 grams
5 ounces |
255 grams
9 ounces |
450 grams
16 ounces |
| |
|
|
|
| Maximum Length |
17.8 cm
7 inches |
20.5 cm
8 inches |
33.0 cm
13 inches |
| |
|
|
|
| Overall Height |
Unlimited |
Unlimited |
Unlimited |
| |
|
|
|
| Maximum Outside Width |
7.0 cm
2 3/4 inches |
8.6 cm
3 3/8 inches |
9.5 cm
3 3/4 inches |
| |
|
|
|
| Maximum Width Between
Inside of Wheels |
4.5 cm
1 3/4 inches |
4.5 cm
1 3/4 inches |
4.5 cm
1 3/4 inches |
| |
|
|
|
| Minimum Clearance Between
the Chassis & the Track |
0.95 cm
3/8 inches |
0.95 cm
3/8 inches |
0.95 cm
3/8 inches |
| |
|
|
|
| Wheels and Axles |
Scouts Canada
Kit Issue |
Scouts Canada
Kit Issue |
Scouts Canada
Kit Issue |
| Axles and wheels may
be lubricated with a dry lubricant such as dry graphite or Teflon. It is suggested that
silicone spray, WD-40 or oil not be used as it may soften the plastic wheels. |
EXAMPLES
OF CAR AND TRUCK DESIGN
April 25, 2005