07/05/2005
FEATURE BY GUEST AUTHORS
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On the 6th of May 2005 the BAR Honda team decided to accept the ruling of the FIA International Court of Appeal, but in a final twist they also published their 103 page defence of the charges made to them by the FIA. As an interested third party, I, a graduate mechanical engineer who currently occupies his time researching fuels and propulsion devices, have been asked to summarize what I've read in both BAR's and the FIA's documents. These are therefore my (personal) views on the subject.
Let's start with the facts. The BAR car was underweight when it was drained of all it's fuel. The real question here is; was there a performance advantage? BAR argue not. They have produced a number of graphs and numeric calculations showing that the car was at all times operating above the magic 600kg limit. Unfortunately for BAR the FIA changed the accusation and instead accused BAR of conducting themselves dishonourably. So we are left with an answer to a question that wasn't asked and an accusation that hasn't been answered. It is very much left for the reader to draw their own conclusions, and as with most things there is no black or white, just grey.
The physics of it are simple. Lighter cars go faster and F1 cars are tricky. F1 fuel systems even trickier. You see, most pumps require there to be fuel present in order to pump properly. The analogy I'd use is when you first turn a hose pipe on with a spray nozzle attached to it. Usually there is a bit of air in the system and the resulting spluttering and hissing results in a less than perfect spray until all the air has left the system. If you think that is bad news, you want to try sucking a liquid and air mixture… F1 cars go around corners and so the fuel sloshes about, especially when it starts to get empty and a pump does indeed start to struggle to find fuel. In order to provide a steady and continuous flow of fuel to the injectors (sprays if you will) a solution is to provide a constant volume of fuel from which to supply the injectors from. In BAR's case this is achieved by using a second tank that is always full of fuel. BAR have also submitted a claim that their fuel pump manufacturer requires at least 6kg of fuel to be available to the pump at any one time.
So sensibly the BAR designers have designed a collector tank that has a capacity of 6kg. Case solved, lets go home. I mean sure, the rules are sketchy about what ballast is and what constitutes a dry car, but car No. 3 weighed 606.1kg, minus 6 gives 600.1kg. On the nose lads, well done, let's go home. But wait, how much fuel can you put in the BAR's collector tank? Well around 11.5kg according to the scales. This now presents us with a bit of a problem. Some of you may think that 5.5kg is not such a big deal, I mean, it is after all only around 8 litres (your red petrol can at home is 5litres). Before I continue, remember that the BAR's fuel consumption averaged around 2.8kg a lap…
Having said all that BAR still have the graphs; let us not forget the graphs. The graphs clearly show that the lightest the car ran all afternoon was 601.9kg. That makes everything alright don't it? Well yes and no. Firstly I find graphs unreliable. Not because there is anything wrong with graphs, just because I know how easy it is to manipulate curves to tell you exactly what you want to see. You see there is always a bit of error associated with graphs and so technically you should always provide an estimate of the error associated with your results. In this case there is no such error stated and we know there is an error because there is all this fuel sloshing about in the tank and that is tough to measure. BAR's numbers are accurate to 1g - about the weight of a couple of sugar cubes - and yet they require a tank with almost double the required capacity…
But let's not dwell on BAR's ability to regulate fuel, what does the FIA have to say on the subject. Well they don't actually have a lot to say at all. If a car is underweight, it is underweight. Sorry, no points for you this weekend, come back another time. Their problem is this. First up, they asked if the car had been totally drained of fuel, to which a member of the BAR personnel replied "yes". Then BAR was asked to remove the refuelling valve to the tank so that the tank could be examined with an endoscope. This was done and the endoscope examination revealed a clear plastic tube running to what the FIA described as a bulk head. When BAR personnel were asked about the pipe the FIA document claims that "When queried, the team could offer no real explanation to its purpose". Oh. But we all know what the tube does, its part of the collector tank, right? When asked, the team couldn't answer this question either. Okay, final question, could the area in front of the bulk head contain fuel? Again no real explanation, whereas everyone who has read this far could now give some level of explanation. Needless to say fuel was found, fingers pointed, cases argued, graphs presented and BAR were after some discussion given a clean bill of health.
Now this statement of events is from the FIA's point of view and obviously is designed to make the case against BAR look bad. BAR's document makes no specific reference to the above chain of events, so take from that what you will. Either BAR was employing some sort of intern to drain fuel from the system or the guy was unsure of what to say when questioned. Better to shut up than incriminate yourself about a system that is not related to your area of expertise. However, this is just conjecture on my part so let's try and get back to the facts.
The BAR system seems hideously over-designed and a little bit heavy on fuel at the end of the race. The car was able to run with as little as 6kg of fuel on board, up to its second pit stop, but had 11.5kg of fuel on board at the end. If nothing else it demonstrates the collector tank doesn't have to be full in order for pumps operate correctly. The official role of the catch tank has somewhat been undermined.
But I want to end with the document I found most interesting. BAR asked several questions of their fuel cell manufacturer (ATL) and the reply to the question as to whether "other F1 teams use integrated forward fuel collectors within the fuel cell" interested me most. The answer was simply that; "all F1 teams use fuel collection systems". I find this illuminating. This would imply that all F1 teams run overweight to the tune of whatever is in the collector tank at the end of the race. I personally would like to limit this amount of weight, BAR appear to positively revel in it.
My final conclusion is that no one on either side is actually answering or asking the proper questions. Why this is, is perhaps the biggest question of all.
James Saunders
PhD Candidate
Dept. Mechanical Engineering
University of British Columbia
Vancouver