F103 Rebuilt 2009
During the winter season 2009/2010 a narrow Pro10 class had been offered in the Bawü-Cup. It was intend for 200mm wide Pro10 and Formula 1 chassis. With 2S Lipo and 13.5T brushless Motor the class promised to be awesome fast and suitable for both indoor and outdoor races. My F103 had been standing on the window sill for quite a long time. I had started to race with a HPI Super EP in the LRP Challenge and later on with my Tamiya TRF 416 in the LRP Challenge and DMC. But this new class already had caught my interest because the car fitted perfectly into its rules. Moreover some drivers had already proven that a F103 could be fast and competitive.
Therefore a complete rebuild of the car was done which also included some tuning. Shortly before Tamiya had introduced the final version of the F103, the 15th anniversary. The long carbon fiber topdeck was available separately and an excellent choice to stiffen up the soft glass fiber chassis (TAM 54081). Also the battery mounting solution seemed worth copying. But before my F103 was ready to contest in its first race a few questions needed to be answered - especially about the tires. What rims would fit the car, what foam types would work, were to get Pro10 adapters and how to build in a 48dp spur gear?
At the beginning I went with Tamiya Group C rims and adapters (TAM 9335088 + TAM 0009388), as they fit the 14mm hexagon rear hubs and can be equipped with Pro10 foams. Regarding the tires some Pro10 drivers from MAC Mettenheim recommended to try GP Speed Tires and to call Mr. Jürgen Plan. He’s a great fella! His webpage isn’t up to date but it’s a pleasure to have chat with him on the phone. He provided helpful advice about different foam types and what hardness to choose. From his other customers he receives plenty of feedback about their experiences he is always willing to share. I’ll do a little summery about my practical knowledge with GP Speed Tires in a later article.
Certainly the Tamiya Group C rims are a bit special and I moreover I didn’t own a tire truer so Mr. Plan’s offer was the perfect solution. I simple send him the rims, then he glued Pro10 foams on, trued them to a suitable diameter and rounded the edges. What retuned were two perfect sets tires ready to run for the first club nights.
In order to get used to the car I started with a 17.5T instead of a 13.5T brushless motor. On a small indoor track this is definitely the better way to go. The power of 13.5T in the F103 demands for a large track. In the hands of an unexperienced driver and with a poor setup it becomes a throughout self-destructive combination.
Today's Hardcase Lipos are a hint too long for the original battery holder. Taping them to the topdeck eliminates those parts and lightens the car. It also improves the ground clearance for side to side movement and by sliding the battery the left to right weight balance can be fine-tuned. But honestly, to fiddle the tape around battery and topdeck is a pain in the ass, especially with the motor wires running over it. However it looks nice.
The combination of the F103GT front axle with moveable upper arms and longer kingpins allows to slide the steering knuckles. By doing so the front ride high can be adjusted and furthermore the angle of the upper A-arms affects the chamber. The complete stack of spacers determines the preload of the front springs and negative the suspension travel.
F103 Setup Testruns Autumn/Winter 2009:
- Tamiya Audi R8 Bodyshell
- Tamiya Group C Rims (TAM 9335088 + TAM 0009388)
- with GP Speed Tires (Pro10 foams, front: 38HF, rear: R2 #30)
- F103 glass fiber chassis, later F103 carbon fiber chassis 3,2mm (LeMans front bumper)
- F103 15th anniversary carbon fiber topdeck
- self-made T-Bar bridges + 4 x TAM9805932 (Battery taped to topdeck)
- titanium screws
- Tamiya TRF damper, Spring Tamiya red
- F103GT frontaxle and kingpins, F1 steering knuckle
- F103 steel rearaxle, F103 diff and spur gear, Tamiya 3mm carbide spheres
- LRP Sphere 2006 brushless ESC
- LRP X11 17.5T blushless motor
- LRP 5300mAh 28C 2S Lipo
- Bluebird steering servo
- Graupner XS6 synthesizer receiver
- Sanwa M11 radiocontrol
With 1111g still a bit too heavy for a F103.