This installment features 2 of Rodney's period race cars that incorporate amazing engineering and a meeting/interview with our own Philippe de Lespinay as he covered the race!
More on Oakland Speedway memories. This time the big race at Oakland Speedway Park Blvd. on a weekend in 1971.
Two Slot Cars for the 1971 Big Race Weekend at Oakland Speedway Park Blvd.
I built these two cars for the big race weekend at Oakland Speedway Park Blvd. on June 27, 1971.
Coupe bodies were required for the sports car races. My endurance sports car featured is a Lancer Porsche 917 coupe. Yes, the Lancer 917 coupe looks like a Ti22 Can Am car with a roof added. The car was driven by Albert Pierce, and Albert won the amateur class this race weekend. Mike Steube won the pro race.
The Formula F1/5000 car has a body made from parts of a Dynamic Matra and parts of a Dynamic March. The car was one of the fastest cars in practice. The formula car race was not run due to the length of time needed for the other races. There were basically two legal formula car bodies for this race (a Matra and a March). I combined the two bodies to get the best handling. The lower part of the body is March and the upper part is a Matra. The nose is Matra also.
Front Suspension Innovations
What is unique about these cars is that they are the first cars in the "modern slot car era" that have front suspensions that allow the slot car chassis to lean and roll in the turns. Remember, back then, slot cars had to have 1/16" chassis ground clearance with all four wheels touching the track.
The sports car chassis was originally built with .062" round main rails and a conventional fixed mounted front axle tube. The car under-steered or pushed excessively. I had local pro slot car driver Tye Quan look at the car. Tye said the chassis did not have enough flex and the front wheels would lock up the chassis in the turns and make the car want to go straight. So I first tried milling down the main rails and splitting the drop arm for more chassis flex. These modifications did help some.
Then I came up with the idea of having a De Dion front suspension to allow the chassis to roll even more without locking up in the turns. The De Dion front suspension consists of a central horseshoe pivot with two small coil springs.
The Formula car was built after the sports car and features a more sophisticated dual A-arm front suspension to allow for chassis roll.
A key innovation with the formula car is that the body nose is mounted directly to the drop arm so the down-force of the nose is transferred directly to the guide flag. Also, the formula car rear wing is mounted solidly to the rear of the chassis so the wing down-force is transferred to the rear axle.
Alternate car body noses and wings are shown.
The Porsche coupe has a split rear spoiler with four side plates. The more conventional spoiler layout is with two side plates. The four side plates resulted in more down force and faster back and forth transitions in Oakland Speedway's S-turns.
Meeting Philippe de Lespinay
Philippe was covering this race weekend and was kind enough to take an interest in my cars and my goals in life. He took pictures of my cars and asked me about the engineering principles behind the slot cars (including the fan car). I shared my theories with Philippe. He also asked me if I wanted to be an engineer? I answered yes, I wanted to obtain an engineering degree. I was in high school back then. It was nice to have a conversation/interview with Philippe and for Philippe to take an interest in my slot cars and my personal goals.
Running the Cars at Eddie's
The Porsche coupe was cleaned up first and was run two weeks ago. I was getting 5.2-second laps on the King track while clutching the bank turn and running orange tires. The coupe was very easy to drive and had neutral handling. I was surprised the orange tires worked with the low spray glue track conditions. I expected the car to oversteer and was surprised with the neutral handling. The open motor is still fast. The car does what Eric and I call the disappearing act going down the front straight. Fast slot cars seem to disappear going down the main straight on the Blue King track and reappear at the bank turn.
The formula car was run this last Sunday after the Can Am race. The track batteries seemed down on power so only a couple of laps were run.
I hope you enjoyed this look back at Oakland Speedway slot car racing.
Next up, the Keiji steel chassis car.
Thanks Rodney. An amazing story and two truly amazing period race cars!