This year I decided that my post-FSAE “burnout” period was over and it was time to go from being a competitor to an organiser, so I volunteered to help out at the event.
So, really briefly, in case anyone that’s reading this doesn’t know- what is FSAE? Well, depending on who you talk to, it’s either a “car racing” or an “Engineering Exercise ” Basically, most universities have a FSAE team in which (mostly) engineering students design and build a race car. The cars all race against each other at the FSAE competition which for Austral-Asia, was last week at Victoria University, Werribee. When I was in FSAE, I didn’t work myself into the ground to accomplish an engineering exercise I did it to win a goddamn race, so that’s what I’ll call it.
Anyway, as a volunteer, I spent the majority of my time setting up marquees, tilt-testing cars, track marshaling and packing up… none of which is particularly interesting to read or write about… but I did get to spend a couple of hours looking at and taking photos of most of the different cars (not all! Sorry to those I didn’t manage to get to), so I thought I’d do a bit of a write up. Not without hesitation- I’m a bit worried that I could offend people by posting my opinions about their painstaking efforts- but then again, the internet is full of the poorly thought out opinions of arrogant assclowns. I belong here. So here’s my ill-conceived opinions on the cars that were there.
(Final note before I get to it: If you want the pictures of your car taken down, I will do so upon request).
UNSW have a strong relationship with their aluminium sponsor so feature a lot of it on their car. It’s an aluminium monococque front/steel space frame rear. They’ve used aluminium extensively through their suspension and drivetrain system. Some notable examples of which are…
…the driveshafts. They’re an aluminium fabrication with Kevlar (I think) flex joints. This concept blew my mind when I first saw. They’ve been running this setup for as long as I remember and I don’t recall seeing any failures. They run an aluminium spool, too.
I like the way they mounted their shocks- low and dead in plane with the engine plate. I wonder what motion ratio they got with this setup?
I also noticed that some of their suspension links are aluminium. I spoke to a team member who told me that they did some calculation on which member flex the least and they made these out of ally. They also made the uprights out of it. I notice that the upper suspension pickups are single shear- I assume they did this so they can adjust their roll centre position by changing over or shimming the ferrules. Lack of antirollbars front and rear supports this… I didn’t think to ask, though.
They have a clever way of reducing compliance in the joint between the engine plate and the chassis- They counterbore the engine plate and weld on a machined spigot on the chassis tube to fit. It’s brilliant. I don’t think it costs them much extra weight if any because the bolt to attach it is no longer loaded other than in tension and so can be reduced in size.
I was talking to a member of their team and he pointed out something that I had missed: They’re running a triplex chain with a very fine pitch. FSAE cars typically have a large rear sprocket because the final drive ratio is obviously a function of the PCD difference between the front and rear sprockets and you’re limited by how small you can go at the front. By using a finer pitch chain, they were able to reduce the size of both sprockets to save weight. According to their team member, it’s stronger, too. Reducing the rear sprocket also gets you a bonus weight reduction in the chain guard, too. It’s usually very heavy as it’s a mandated material and thickness for safety reasons… 2.77mm steel, if I recall correctly. I CBF looking up the rules, so don’t use this number to design your car. 😉
The mounting of shocks toward each other in plane with the engine plate is ubiquitous this year. Penske and Ohlins both have a popular damper that is well suited to FSAE cars and easy to package in this way, so I suppose I shouldn’t be surprised to see designs converging together. One of the challenges that does arise from this kind of setup, however is packaging an ARB. Here’s RMIT’s solution.
A photo of their shiny carbon plenum and their carbon wishbones. Those uprights look familiar I think they’re carryover.
Newcastle put a lot of effort into their bodywork this year and came to the competition with a very attractive car. I’d be sort of inclined to leave off the panel on the rear that goes up to the rollhoop but it sure does look nice.
Under the bodywork, you can see that they’ve mounted their shocks and bellcranks off their rollhoop braces. Their driveline is mounted off the rear engine mounts and tensioned with rod-ends.
They’ve tied their bellcranks together with this bolt-on member to stiffen the system up a bit.
Their uprights are folded and welded sheet steel. They look very well made and quite light, though perhaps a little bit to thin at the wishbone pickup points- there might be a little bit of compliance in heavy cornering. I just noticed looking at these photos that there’s lockwire running between the two lower pickups… I’m not sure what that’s there for… maybe to stop the jam nuts from loosening?
One of the challenges of Monash‘s semi-sprung wing mounting is that the drag link needs to flex slightly in roll without letting the wing swing around too much. This year, they’ve tried a new approach by using a flex plate rather than crosslinks. The wing has been painted black to cover manufacturing flaws- vacuum bagging every possible gram of resin out of the wings takes its toll on appearance.
Monash’s cars have always been a bit on the heavy side and this year is no exception. The guys have apparently done a weight analysis and nothing in particular is excessively heavy, but it all adds up in the end. I think a couple of kilos could be saved in the bodywork and closeouts by using thin fibreglass or carbon rather than aluminium. Also, I can see a lot of ACL heat shield in front of the engine- maybe 3 kilos worth (the stuff is really heavy). I think the stuff is intended for much higher temperatures than what it’s being used for. The temperatures on the engine side of the firewall are probably low enough that something much less dense could be used- or with some planning, maybe some ducting.
Maybe there could be a cutout in that inner endplate to shave off a bit more weight.
Melbourne were looking very fast this year with a well set up car. Tragically, they suffered an engine failure in the second endurance.
Steel fabricated uprights and some very small wishbones.
There’s a few grams of free weight saving in those wheel bolts.
There’s currently some conjecture (and much better photos) on their facebook page as to whether they had a lubrication failure which caused the thrown rod which threw the piston into their valves or if they had a valve retention failure which sent the valve into the piston which caused the broken rod. Regardless of the cause however, it was a very unfortunate end to the competition for the Melbourne guys who were looking very fast until then. Here’s some shots of the holes in the block:
Auckland’s always show up with a very well made and fast car but are typically plagued with powertrain related reliability issues.
They run a very narrow track in order to navigate the tighter sections of the track as quickly as possible and as a result need to lower their COG as much as possible in order to avoid tipping. One of the ways they do this is with their custom transaxle. They have a carbon fibre one, but this was swapped out for the aluminium backup prior to the comp.
They use the same uprights front and rear to save time and effort. They make centrelock wheels and drive them with those drive pins sticking out the hub. Monash owes their 2009 finish to those drive pins, incidentally. Their wheel speed sensors pick up off the slots in the brake rotors and the brake calipers look to be made in-house. They adjust camber the same way that Wollongong adjust their chain tension.
Dampers and bellcranks mounted to the chassis as closely as possible in order to get as much of the forces as possible to be transferred to the carbon chassis in shear.
A lot of the drivers on the driver swap day were saying that Curtin’s car was monstrously fast. With a little bit more driver training, these guys are going to pose a serious threat to the current front-runners.
They’ve welded an RHS bulkhead to the chassis which saves them from having to machine an aluminium engine plate. Their uprights are machined aluminium with bolt-on alminium clevii. I’m not sure why they adjusted their camber by shimming the bottom rather than the top, though. Maybe they forgot to design excess camber in so they could shim camber out of the system?
Another dry-sump system by the looks of things.
Looks like there was a slight interference with this bellcrank so it was angle-ground to clear. It looks like an obvious thing to miss now that it’s all together, but I’ve done very similar things before. It’s easy to forget to check clearance for all orientations when you have to make a quick design change to a welding fixture or something. Like TDU, they’ve fishmouthed their wishbones prior to welding.
TDU’s car looked very well made but took quite a beating from its off track excursions. Nonetheless, they guys managed to get things together to finish endurance with a very respectable score.
Looks like they tension their chain with eccentric rings that are clamped tight with that nut at the top. They run a very small diameter torque tube which transitions rather quickly to the large diameter of the hub which looks like it may cause a bit of a stress concentration where it mounts into the bearing. The right hand side is unsupported. It looks like they did this because they wanted to run equal length driveshafts to avoid torque steer. I don’t think torque steer would have been a problem here, though. I used to think that torque steer was caused by unequal length driveshafts because the longer shaft twists more and “doesn’t drive as much,” but I thought about that for a bit one day and decided that I was wrong. Torque steer is, to my knowledge, actually caused by the driveshaft angles being unequal from side to side. The mismatch in angle of the drive shaft axis to the wheel/hub axis on each side creates a resultant torque around the steering axis. If both driveshaft angles are equal, these two resultant torques cancel each other out. If they aren’t, they don’t. However, if the wheels aren’t steered, and there isn’t any compliance in the system, the toe links will resist this torque and there won’t be any torque steer.
I know I’ve said this too many times already, but if I’m wrong here, please argue with me- the last thing I want to do is spread misinformation!
Anyway, if they really did want to run equal driveshaft lengths, why not move the right side engine mount a bit more to the right? On an unrelated note, TDU seem to favour split lock nuts over nylocs.
They have gorgeous gusseting on their wishbones… I suppose they must press them to get them into this shape. You can also see that they have cut their toe link into a fishmouth shape where they weld it to the threaded insert. I see this a lot on formula fords, old formula 1 cars and so on (see my previous post with photos from the historic races at Sandown) but not often in FSAE. This is good because there is more weld area and the weld is loaded in shear.
ECU’s car was a real monster this year, making a 47-point-something autocross time. If not for the two second penalty for knocking over a cone, they would have won the Autocross. They won the Endurance, too. With a little more development on their static events, these guys may well have won. Monash had better be on their toes!
There’s mounts for a pair of drop links for an ARB on those bellcranks, but it all looks to be absent. They might have decided it wasn’t working well enough, taken it off for the weight saving and tuned using the front bar. I might mention here that stripping as much weight out of these cars is critical not just because of the engine restrictor and small size, but also because design judges are very critical of car above 220kg.
Nicely machined bellcrank. The hex section tacked onto the pushrod is a nice touch, too. When I was at Monash, we’d scratch up our links by clamping around the ends with vicegrips when adjusting them because we never took the time to do this. It looks like the wing mount picks up on the chassis just behind the bellcrank in this photo. They’d only have to move the mount a tiny bit aft and outboard and they’d be able to mount it on the bellcrank for a semi-unsprung wing… please forgive the Monash bias! 😉
A big oil reservoir. I always figured that a dry sump system would break even on weight because the oil reservoir and extra pump would way about the same as the extra oil and accumulator that you’d need in a wet sump, but judging by the size of the tanks on all the dry-sumped FSAE cars here, maybe not.
ECU’s carbon skinned aluminium honeycomb panels give them the advantage of being able to stick their wishbones on the chassis wherever they want without having to worry too much about load paths. I imagine they’d have some sort of bulkhead on the inside to avoid oilcanning, but I couldn’t see. The front bellcranks look super light! I’m kind of nursing some sort of pinched nerve in my leg at the moment, so couldn’t be bothered getting on the ground to look, but apparently, there’s a pitch damper hiding under there. I suppose they need it because they’re running a bit more pitch stiffness than usual to avoid grounding their sprung front wing (I assume it’s sprung. Please correct me if I’m wrong).
The Wollongong team looks to be on the way up- flying under the radar to secure third place at this competition. Well done, guys!
I learned from our 2006 car’s chain tensioner that the only part of a FSAE car that should ever rely on friction is the tyres. Everywhere else, there should be a mechanical way of locking it down. Here’s Wollongong’s clever approach:
The ‘Gong had a cute brake light cover that lights up with their team insignia. Unfortunately, the design judges had some reservations about how visible it was, so they had to run the LED brake light above the cover. Below it you can see what looks to be a machined aluminium spool. Looks like there’s gasket goo sitting on the join line between the spool and the CVs which implies that the CVs are not blind bores, but holes all the way through.
Their seat displays some incredible craftsmanship. The only way I can make carbon fibre look like that is with a liberal application of bog and a faux carbon fibre stickers.
On the driver swap day, I had a conversation with one of the Wollongong guys that went something like this:
“Your hubs look very light”
“Yeah… a little too light.”
At this point I realised that I couldn’t see a spigot for the wheel anywhere on the hub because it had broken off! In any case, they had a set of hubs on the car long enough to complete the competition and secure a third place finish. They also seemed to experience an intermittently sticking throttle while shaking down the car prior to the driver swap day.
Looks like a custom made caliper. Their wheel speed sensors look very lightweight.
Small and neat front ARB. I should note here that the only thing worse than my writing is my photography, so, uh… don’t bitch.
Strain gauged uprights. Had a quick chat with one of their guys. They were apparently trying to correlate their accelerometer data and wishbone stresses to get some information about their tyres. Unfortunately, they didn’t apply their strain gauges all at once and then immediately test, so they found that their readings were faulty. I don’t have any first hand experience to back this up, but I believe that strain gauges have a very limited lifespan in this sort of application. It’s really good to see people going to this kind of effort to gather their own data, though and I’m really keen to see if they show up next year with some positive results.
edit: I don’t seem to have many photos of their car and at first I attributed these photos to Wollongong. Whoops! It’s a good thing nobody reads my blog or else people might get upset 😉 I’ll try to dig up some more later. As it is now, all I have is a shot of their front ARB link. I’m not sure why it’s curved… As far as I could tell, it’s a U-bar type ARB, so as the drop link moves in an arc, the adjustor could just pivot slightly to accommodate.
Waikato University had only 5 guys with which to design and build their car, in comparison to the larger teams having 10 times as many people at their disposal. As a result, the guys have had to come up with some innovative ways to cut down the manufacturing effort as much as possible. When I first looked at it, one of them asked “Do you like our car?” I had only just started to look at it, so I had nothing to say at the time- I wish I’d been asked towards the end of the competition when I’d had more time to look at it so that I could have said “I think it’s fuckin’ awesome!”
Their rear uprights were the perfect example of this approach. They are an RHS section with a bore laser cut in the middle and a machined bearing cup welded in place. The hubs are an off-the-shelf Taylor race (I think) unit. These two features alone probably shave two man-weeks or so off their manufacturing time.
Interesting front wishbones. It looks like they wanted to run the same wheel shells front to rear, but with the opposite offset (simple to point at but hard to explain in words… imagine taking the rear wheels off the car and then bolting them to the front inside-out). This caused a clearance issue on the front at full steering lock, so they made the wishbones like this to clear.
The welding on the intake is flawless.
That seat sure does look comfy. French seams and all, very nicely made.
UWA unfortunately didn’t run but they sure did show up with an interesting concept. It’s apparently intended to be a mechanical application of their famous Kinetic setup. The car is partly suspended by the diffuser and partly on a single flat spring front and rear. This decouples ride and roll. Roll stiffness is given by a single antiroll bar in the middle of the car that is moved fore and aft to adjust the front/rear roll stiffness percentage. Single wheel bump is handled by the diffuser warping/bending diagonally. I’m keen to see how this will all work out.
The driveline was unfinished but from what was there, it looks like it was intended to be another eccentric-adjusting setup. Unlike most other teams, though, this one was supported on two thin sheet steel mounts, rather than machined aluminium.
The lower arms on the uprights have been moved upward so that they can mount on the top of the diffuser’s tunnels. Didn’t get to see the hubs but the uprights look very light.
QUT were running a relatively large damper that was very popular a few years ago (Ok, I just noticed from a post on the FSAE-A facebook page that this was actually a 3rd year car. Makes sense). They’ve used this double-bellcrank sort of design in order to package the dampers next to each other while keeping the pushrods at the same angle. I turned my head inside out a few times trying to figure out how well the loads from this were resolved and never really came to a conclusion… There’s the two aluminium vertical driveline plates, plus the horizontal steel plate tying them together… then there’s the pair of chassis tubes in a X shape that tie to the rear bulkhead to stop lozenging, plus gusseting all under the little pillow blocks… It gets trickier the more you look.
Unfortunately, I didn’t get as much time to look at this car as I wanted to.
I’ve always liked University of Sydney. This might be due to personal bias- I have spent a bit of time talking to the two academic advisors there, Greg and Andrei and they’re both really awesome and knowledgeable guys. Greg actually gave me some vital advice that really saved my arse in 2009. But back to their car… They’ve been slowly getting faster and faster and this years car was particularly impressive.
USyd were one of at least two teams that I noticed pouring custom expandy-foam seats at the competition. I think in terms of maximum output for minimum time investment, this approach can’t be beat.
A neat way of adjusting the ARB. They’re running it through the jacking bar which is a good way of getting two functions out of one pair of mounts.
The bellcranks are very simply made- no welding. There’s a stiffening member that’s simply bolted in. Looks like there could be some room for some speed holes in that rear sprocket.
USyd’s driveline doesn’t look to be carrying a gram of excess weight. I was a bit worried about whether it would last, especially with the lack of lockwire on the mounts but it lasted the endurance just fine. The engine plate is very thick, though. I think there’s some room to strip out more weight there.
Their uprights were very cool. They were made out of two machined aluminium shells that were then assembled together and welded around the middle. They have a bracket built in to which they can mount a tyre pyrometer mount which they ran for the competition to collect data. Their rear brakes are tiny!
University of South Australia didn’t waste any more time than was absolutely necessary with their bodywork which probably didn’t impress the design judges but gets a thumbs up from me (I’m definitely a function over form kind of guy).
Different wheels front vs. rear… both of which look different to their testing photos on their facebook page. I wonder what the go is there?
This is something you don’t often see on a FSAE car: An analogue fuel pressure gauge. Most teams see it as unnecessary because if you’re having engine problems and you want to know if you have fuel pressure, you can simply get your team laptop and a really long extension cord (because the battery is always dead), find the bus cable, plug it in, turn the car on, open your motec software, navigate to the appropriate screen, forget where the fuel pressure is shown, give up and crack the fittings on the fuel rail slightly to see if fuel spurts out.
Some very nice welding on that plenum.
Machined aluminium rear uprights. I wonder why they didn’t design sidewalls on the upright’s clevii?
It looks as though UQ plan to do a lot of development with this year’s car. They have adjustable pickup points in the chassis so that they can play around with anti-squat and anti-dive. They also have 5 pickups in their bellcranks to change wheel rate. Their roll hoop braces come very high up on the roll hoop and are quite long. I think the braces are a mandated thickness, so they might be able to cut out some weight by laying these down a bit more (mind you, they’re a mandated angle, too). Rather long primaries and small plenum volume compared to most of the other cars I saw there.
That torque tube looks like a real bear to get in and out.
University of Adelaide had a solid and reliable car this year, completing all events for a top-ten finish.
Their wishbones have a rather large steel insert in which the spherical bearing is mounted. There’s some potential here to cut some weight out of the car. Looks like the pullrod mount is slotted into the gusset and welded from the top which would make things much easier for the welder.
Nice looking upright. I’m confused by the sensors they have here. There’s a familiar looking hall-effect sensor mounted facing into the upright. If it was pointing at the brake rotor or a trigger wheel, I’d say it was a wheel speed sensor, but I don’t know what it could be doing at that angle. Also, the little red sensor mounted on the aluminium plate. A brake rotor pyro perhaps?
Looks like the toe link is aluminium hex bar.
Sophia University had a heavy but very powerful car. A photo of their blower is shown below. Unfortunately, not many of my photos came out visible- when they weren’t competing, the Sophia guys kept their car in the pit where there isn’t much light.
This shabby, dark photo sort of shows Sophia’s intake which looks to be rapid-prototyped.
So that’s the wrap on the cars I covered. Again, please don’t take offence if it seems that I was critical of your cars. You’re all winners- building a car from scratch isn’t easy.
If anyone has any further comments, I’d love to hear them! Post away.