Several years ago I purchased a Scaleauto Porsche. I thought that our group might be interested in racing these little machines. The idea did not catch on because we were (are) running modified H bracket chassis with more powerful motors that can be built for much less than the Scaleautos. We allow several different H bracket chassis including Scholer, Plafit, Slotting Plus and Scaleauto. Some of the guys use the Scaleauto chassis as a starting point. These have adjustable axle hangers while my out of the box Porsche did not. Although Scaleauto sells parts for an adjustable hanger, they cost $29 plus shipping. Come on, the complete chassis (with adjustable hanger) costs about $50. As a consequence, I fabricated my own for a mere pittance.
Below is an image of the finished product (more images of the finished product are shown at the end of the post).
I think that the conversion was certainly worth the effort. The stock Scaleauto Porsche was able to run Electron Raceway lap times around 5.8 seconds. The converted Scaleauto ran lap times right at 5.0 seconds
The project included the following modifications
- Fabrication of an adjustable axle hanger for the rear wheels. The axle hanger would accept bushings for a 1/8 inch axle
- The front axle hangers would not be modified; however, I machined 1/8 inch bushings to fit the stock hanger.
- ProTrack foam rear tires are used but cut down to a bit less than one inch
- Ground clearance of the stock Scaleauto is about 1/8 inch. Our racing specifications call for a minimum clearance of .055 inches. The rear axle hanger was adjusted so that ground clearance with the cut down tires was .055 inches
- The ProTrack front tires were cut down to the point where ground clearance was .055 inches. This turned out to yield a front tire diameter of a bit less than one inch.
- I used a sealed ProSlot 16D motor (our spec for H-bracket racing) and used a motor bracket supplied in one of my older Scholer kits. If you choose to undertake this project, a suitable motor bracket will need to be found or you will have to fabricate one.
- Motor cooling holes were drilled in the chassis
- Brass side pans were fabricated to add stability and weight to accommodate the much more powerful motor.
- The side of the chassis was cut between the stock mounting holes to create a bump in and the side pans were attached (images and more on this later)
- The chassis was cut at the back to accommodate the new spur gear (images and more on this later)
- Lead was used in the recess of the chassis near the front and near the rear of the side pans, again to add stability and weight.
- The body was mounted to the side pans. I used clear L shaped plastic dry wall edge protectors. These come in 8 or 10 foot lengths and cost only a few dollars. I cut about an inch from the protector. I used super strong two sided tape (available at Home Depot, Lowes or a hardware store) to attach the one inch L bracket to the body. A hole was cut and countersunk in the side pan and small bolt used to attach the bottom side of the L bracket to the side pan.
Fabrication of the adjustable rear axle hanger began with selection of available parts shown below (disregard the brass L shaped strip. In the end, I decided not to use it).
The first step in the process was to fabricate the axle hanger. For this, the motor bracket was cut in half and spread. To assure proper axle alignment a quarter inch brass tubing was slid into the cut halves. How wide should the hanger be? I used the Scholer measurements. This is because if the hanger is too wide, the wheels and gear attached to the axle will be too long and the track will be greater than 3.25 inches. The side of the brass tube that faces the axle was cut so that the motor pinion and spur could mesh (This was done later). The brass tube simply added strength to the assembly. See below
A .025 inch plate was soldered on the outside of the motor bracket and trimmed. I made it a bit taller than the Scholer bracket to make sure it could handle from .925 to 1 inch tires. Two vertical slots (not shown) were cut beginning at the top of the plate so the hanger could slide up and down. The width of the slots were determined by the size of the bolts used to fasten the axle hanger to the bracket.
The aluminum L bracket was cut and mounted to the chassis (I used the existing holes in the chassis). Its position was determined by the placement of the original axle hangers so that when mounted, the bracket will hold the axle in the same fore/aft position. Note that the new axle hanger should be offset so that the spur gear can be mounted on the proper side of the chassis. The hanger and bracket was held together with nuts and bolts.
Below are a few images of the bracket in various stages of completion.
Side pans were fabricated with .062 inch brass (originally .75 inches wide). The sides of the stock chassis were cut to include a bump in. In addition, motor cooling holes were drilled. Finally, a bit of the chassis near the rear was cut to accommodate the spur gear. Below is an image of the stock chassis and modified chassis as shown from the underside to illustrate these modifications and the pan attachment.
After chassis modifications
The completed chassis from above
More images of the finished product
