The Southampton University Formula Student Team has worked all year to produce Stag 3, its 2016 Formula Student contender. With the lightest, fastest, and most advanced vehicle that the team has produced to date, we went into the summer with high hopes of a good finish at the events.
The Silverstone event was our best ever finish in the UK, and then strong performance in the dynamic events in the Czech Republic led to a 14th place finish in a European event. Things did not go entirely smoothly along the way, but overall the results are just reward for the efforts of the team in 2016, and provide a very strong starting point for the 2017 car.
This article covers the manufacturing and logistics that have gone in to getting the car ready for two events, and some of the work behind the scenes which is already going on to prepare the team for the 2017 racing season.
The Build-Up
Manufacturing of the car started early in the year with the chassis, and continued in earnest at Easter with a big push on suspension, aerodynamics, and drivetrain components. The process was more carefully scheduled and controlled this year, learning from the mistakes of the previous year.
A list was kept of all of the components which needed to be manufactured, along with the processes required. This optimised our use of resources, so that as soon as a tool or machine became available it could be used.
We have a significant restriction in our build because we are only permitted to use power tools inside the university workshops, which are open 8-4:30 five days a week. This time forces us to be careful about planning machining operations and preparing materials and templates so that we can jump on and get the job done as soon as quickly as possible.
The build was paused during our exam period in May, and resumed at the start of June. A number of issues were found with the car when we came back after exams – fresh eyes and a break are always recommended because it is very easy to get tunnel vision on certain issues. We had a lot of work to do before the launch of the car at the University’s design show in the middle of June.
Due to conflicts with the university’s Eco-Marathon team, a number of parts which had been outsourced to the EDMC were over a month behind schedule arriving. Let that be another lesson – avoid scheduling conflicts and communicate with people who are sharing the same resources. It emerged that in order to present the car in a ‘mechanically complete’ form, we would have to improvise some uprights. The geometry of the uprights is such that this is not an easy task.
In the space of around three hours, MDF uprights were designed, laser-cut, glued together, and assembled to the car. We had no idea whether they would hold the weight of the car, but 6mm MDF seemed to be pretty strong.
The car was painted in the evening and then assembled, from the chassis outwards, overnight. This was the first time that the suspension had been bolted to the car in full, and it was testament to the massive improvements in manufacturing processes that it slotted into place first time. The car was packed up and taken to the design show in the morning, and covered in a delightfully coloured tarpaulin ready for launch.
The Launch
The car was launched at the opening to the university design show, which is a major attraction to business, industry, and academia. The opportunity to present the car to a distinguished crowd opens the team up for praise and criticism in equal measure – plenty of photo opportunities and people keen to get a look, but also lots of questioning from those keen to challenge some of our design decisions. This makes for good practice for the design presentation itself.
As the first year that we have had wings on the car, there was plenty of interest in the aerodynamic features of the car, along with several comments about the carbon suspension and the cling film wrapped around the tyres to protect the rubber. Nobody mentioned the wooden uprights…
The launch event was very successful overall, beating previous years where we have struggled to get a complete car out on show. The interest in the car was very encouraging, and the work done to get the car mechanically ready well in advance of the race season proved to be very beneficial.
FSUK
Over the next few weeks, several more long shifts were pulled to get the powertrain and electronics ready for competition. The final few outsourced components trickled in and were assembled onto the car; the MDF uprights were replaced with their aluminium alternatives and the spare set of wishbone inserts arrived ready for manufacture of backup suspension.
The last remaining part to come back was the throttle body – a fairly critical part of the whole intake system. While waiting for the new intake system, we tested the car with our intake from 2015. The 2015 intake didn’t meet 2016 regulations, so could only be used for our testing and would have to be swapped out before the event. The testing was very successful – the car was quick, seemed to be reliable, and didn’t exhibit any major mechanical flaws after the shakedown.
Testing continued for a few days to stress the components repeatedly – brake tests and acceleration runs were practiced to put the suspension and powertrain systems at full load. Both responded fairly well, so we took the car to Silverstone with high hopes of a good result.
The intake was finally finished on the Thursday of the event, so it was driven up separately and assembled on to the car at Silverstone. In the process of changing the intake, however, we discovered a number of metal components in the sump – never a good sign. It emerged that these were parts of the oil pump, which had failed at some point during testing.
We acquired a new oil pump from our spare engine (in Southampton) and fitted it on Friday, eventually getting through technical scrutineering late that afternoon. We moved on to the noise and brake test on Saturday, but had trouble getting the engine started. We continued to tweak the engine mapping, to try and get the engine to start, but it was never running for more than a couple of seconds at a time… and even then, it needed the throttle fully open to idle.
Despite spending all of Saturday and most of Sunday trying to get the engine running, it still wouldn’t cough in to life so we couldn’t pass the noise test. After getting the car back to Southampton, it emerged that the oil pump failure had caused the piston rings to melt, essentially writing off the engine. It was difficult to tell whether this failure had occurred in testing or at the event, but nonetheless it was clear that we were going to need the spare engine for our next event.
Although we didn’t pass scrutineering, the event was positive for a number of reasons. Firstly, we achieved our highest ever points total and highest ever finishing position at FSUK, courtesy of excellent scores in the design and business presentations. The team is getting quite accomplished at the static events. Secondly, one of our team members, Alvaro Sanchez Vela, was selected for the ‘Most Valuable Team Member’ award. It was absolutely deserved as his dedication to the team this year has been second-to-none.
FSUK was won in the end by Rennteam Stuttgart – a historic win for a combustion car in the era of electrical dominance. This followed the disqualification of a number of top electric teams for a variety of infringements, including aerodynamic exclusion zones (Delft) and exceeding power limits (Zurich). The lesson taken from the event is that speed is one thing, but that taking care to meet the regulations and design within the limits of the rules is part of the challenge. The Deflt team walked out of the awards ceremony as a protest against their disqualification, attracting much disdain from the remaining teams. The spirit of the competition is just as important as ever.
FS Czech
After Silverstone, the team returned to Southampton to prepare for the event at Autodrom Most, in the Czech Republic. In addition to changing the engine and properly fitting and testing the as-yet untested intake system, more dynamic testing was done. This revealed some weaknesses in the lower wishbones – they were clashing with the tyres due to rear toe compliance, leading to the press-fit bearings coming out of the inserts.
Repairs were made to the wishbones using the spare inserts, and the toe compliance was given a temporary fix. After a little more testing, the car was ready to travel to the event. Transport was courtesy of one of the university’s UAV support vans. This was offered free for the whole week of the event, giving us a base which was the envy of the paddock.
Building on our results from Silverstone, and with two weeks of testing offering much better reliability, we started all of the dynamic events. A 14th place finish was just reward for the team’s efforts this year. Unfortunately, a brake issue meant that we couldn’t finish the endurance, and we could have finished even higher up the field.
The wet conditions on Friday gave us an opportunity to test the car in more slippery conditions. Our drivers gave the crowd plenty to cheer about, with a number of pirouettes keeping the observers entertained. We also set some very competitive times, proving that all of the work done this year to improve the vehicle performance has paid off, and we have a very fast baseline to work from for 2017.
2016 Handover
In the lead-up to the events, a huge handover process took place between the current committee and the next committee. The incoming team were elected around May, and since then I have worked on a handover document which explains the processes used to design and build the suspension system. It also covers a lot of the problems that have occurred in 2016, and offers suggestions to improve this for 2017.
Also included are walkthroughs of all of the tools and software we have used this year. Any scripts and code which has been written was documented and included, so that there is a reference for any future group leaders to refer to if they need to use the software or experience problems with it there is a guide which will allow them to fix it.
Recommendations are made within the document, and suggestions of areas to focus on for improvement are listed. However, there is a limit to the amount that can be transferred. Specific areas to change, blueprints and brand new designs, and direct instructions for the 2017 season are avoided. This both encourages the new group leaders to take ownership of their own design, and forces the information to be relevant for any year in the future of the team.
The document stretched to well over 50 pages, and was handed over with all of the documentation, software, and CAD files we have developed this year. The hope is that the new group leaders will be able to use this information as a starting point, and then take on their own ideas to develop and produce new concepts.
I would recommend writing something like this to every group and team leader in the Formula Student world. Knowledge transfer between years is vital to the success of the team over multiple years. Writing things down also reinforces the knowledge that has been acquired during the year; similarly, documenting code and cataloguing content produced during the year encourages it to be written well and produced carefully in the first place.
The handover process also included a number of meetings to pass information through face-to-face, and this form of knowledge transfer should be encouraged as much as possible. It allows ideas to be discussed, and gives more context to the suggestions that are made. Demonstrating how to use tools is more effective than writing a user guide, so as far as possible this is the approach that should be taken.
With the amount of information that has been passed on to the 2017 team, as well as the quality of the car to be used as a starting point, the 2017 season should be by far the best yet for the Southampton team.
Alex McCormick 