Honda RA1082: Developing a hybrid system for use on a F1 car
Honda knew that it could not package a hybrid system on its existing 2008 car the RA108 without making substantial changes. So it built a one off special test mule. The Honda R&D engineers took a RA106 chassis (from 2006 & 2007 with Super Aguri) and modified the area around the fuel cell to accept the battery pack. They took this approach to ensure that the car retained its centre of gravity as much as possible. This mule became known as the Honda RA1082 (and is distinct to the Honda RA108).
The Honda RA1082 in testing
Honda felt that while placing the KERS components in this part of the car had some advantages in terms of electrical safety and centre of gravity height, it also reduced the volume of the fuel cell by an unacceptable amount. Originally the RA106 fuel tank could hold 140 litres, but on the RA1082 it could only take 83 litres.
On the RA1082 installation the Motor Generator Unit (MGU) was mounted inside the transmission casing. This was due to the engine homologation (development freeze) which had been in effect since 2006, no engine alterations were allowed and connections could not be made to the drive shaft. Reducing any bulge on the transmission casing was a priority for aerodynamic reasons so the MGU was connected to the layshaft. This layout limited the diameter of the MGU to 100mm.
The RA1082 build was completed in April 2008 and the team took the car off to the Santa Pod drag strip where Alex Wurz completed a 2.4km shakedown run. But they build had overrun and the planned
two weeks of system checks could not take place fully, the upshot being that the system could not be operated at the shakedown.
There were problems at the factory too, when the hybrid system was developed Honda R&D engineers could run it on a specially constructed test rig, but at the F1 team in Brackley all they could do is check it by running it on an actual car, by firing up the engine. “To fire-up the engine required a large number of engineers and mechanics and a launch sequence starting several hours in advance” a Honda R&D engineer explains. “For the sake of engine durability it was not possible to let it run for long periods with no load, so we could only get the desired data in a very short period of time, and it was difficult to do system check of KERS. Ordinarily fire-up only takes place once or twice before shake down, but fire-up was conducted dozens of times with the RA1082.”
A week later after many of the small issues thrown up by the lack of preparation time had been resolved the team returned to the track. This time at the Silverstone National Circuit the car would be subjected to more realistic running, James Rossiter took the wheel and the KERS was run at 25kW assist and 35kW recharge. 25km of running was completed.
The team subsequently made more enhancements and just under two months later Mike Conway was at the wheel, this time for 48.6km of running on the Silverstone Stowe circuit, where the system was run up to is full 60kW capability.
From there even more detail changes were made and the RA1082 was shipped off to Jerez to take part in an official F1 group test. Mike Conway and Alex Wurz shared driving duties with the system running at 60kW and a total of 314.4km was completed. During that test the KERS reduced total lap time by about
0.4 seconds when assist with energy of about 400 kJ per lap was applied. Car speed increased by 7 km/h with distance gain of 7.8 m (1.6 car lengths) with continuous assist of 324 kJ on one straight.
“I was impressed by how amazingly fast I approached the hairpin when the assist kicked in. It makes acceleration from the engine alone feel as if carrying a heavy weight” Alex Wurz exclaimed after trying the car out. Honda were just as impressed and felt ready to take the next step.