Back to USEFUL SIMULATIONS.
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Claude,
I agree completely with your opening post. (Yes, really, and the world still turns!)
And also with Edward's, and susequent, posts.
But what do the students say? Where are your views on "simulations'? Specifically, how often can the students say they have made really USEFUL DECISIONS based on simulations?
I would like to hear examples of such, because I see precious few.
~o0o~
To get the ball rolling, consider the big-picture "point-simulators" that are very useful in setting the overall direction of a team. This direction includes deciding how much of the team's scarce resources, such as man-hours, money, +++, to spend on the different events (eg. gaining static-points vs dynamic), and what overall concept of car to build to maximise total points (eg. cost-points vs speed-points), and so on.
This type of simulation was used by Geoff and his team at RMIT over ten years ago, and was very successful. They were top-of-the-world for a few years around 2006+. Geoff then spelled out this approach in his "Reasoning..." thread, which most older-heads here recommend as compulsory reading for all FS-ers. Geoff even pointed out how easy it was to write his first simple point-simulator. It took ONE WEEKEND!
Then in 2012 Claude's company released a somewhat more sophisticted simulator (IIRC, written by Pete Ringwood?). This was aimed largely at the FS/FSAE world, and was/is GIVEN AWAY FOR FREE! Students need only google "OptimumLap" and find free access to track maps, typical FS-car parameters such as masses, hps, CdAs, ClAs, +++ (well, a lot of that stuff was there last I looked).
Sure, both the above are "only" point-mass simulators, but they are certainly enough to get a team started on the big-picture issues.
So what have teams done in the five years since OL was made FREELY available to all FS-ers on the planet?
Well..., following Julian's suggestion to "call them out personally", I present here three case studies taken from the very small FSAE-Oz world.
~o0o~
1. RMIT(C) - As noted above, around 2006+ RMIT adopted the "simple, lightweight, single-cylinder-450cc, 10" wheels, and no-aero" car-concept. They were the first team worldwide to achieve high success with this concept. This concept direction, of course, was encouraged by their own in-house, very simple, one-weekend-to-write, points-simulator.
Some years later (possibly after OptimumLap was freely available to all teams?), the later generation of RMIT students decided to CHANGE DIRECTION on overall concept. The single-cylinder engine was tossed and replaced with a larger capacity twin. And a TURBO was fitted. And a shed-load of carbonfibre was also added, with the car somehow managing to get heavier each year. The car was clearly evolving in the direction of "Mini-F1" (though not very mini on mass!).
However, despite the awesomeness of its new powerplant, no significant aero was added. Note that even a very simple simulator suggests that the main justification of mega-horsepower is to offset the extra aero-drag from a mega-downforce package.
Anyway, the end result of above changes is that RMIT cars have struggled to turn a wheel at most competitions in recent years.
So, can anyone at RMIT please explain how they arrived at their current car-concept, and what, if any, "simulator results" they have to justify this change?
Or, putting it another way, was this change driven purely by your testicles?
~o0o~
2. UTAS - In 2014 the Tasmanian team returned after a long absence from competition. Their 2014 car was of ~2006 RMIT style, being a quite simple single-cylinder car, albeit, and understandably, of relatively "inexperienced" execution (ie. many small deficiencies, and it weighed ~220 kg). Nevertheless, despite barely completing Skidpad and Accel, and not even starting AutoX, they finished just below mid-field at the 2014-Oz-comp (14/24 and 428 points).
If, for the next year, they just aimed to score points in all events, and perhaps tidied-up the car's design and fixed some of its defects (perhaps easily cutting 50 kg), then they would have comfortably made top-five in 2015.
But what did they do? They COMPLETELY CHANGED DIRECTION!
Their 2015 car was a ~250 kg heavyweight, with "awesome" four-cylinder powerplant, and all-options-ticked-including-the-kitchen-sink. Err, except for aero-package, which was planned but not delivered in time. And by the end of the 2015-comp they had gone backwards, with an overall score of 415 points.
In 2016 they piled even more junk on the car (yes, even a pneumatic-paddle-shifter for the gearbox!), and with a massive expenditure of time and money they managed to move a little ahead on points. But 2016 was the year where almost all the usual Top-Teams, even Monash, managed to shoot themselves in the foot.
By my reckoning (ie. my simulations), the very expensive 2016-UTAS car is barely faster dynamically than a tidied up version of their 2014 car (Edit: which had ~25 hp!). A better "engineered" version of the 2014 car (ie. better designed, developed, tested...) would be much faster. And a lot cheaper (and easier) to build, so better Cost score. And more Fuel Efficient.
So, can anyone at UTAS justify the above change in direction on the basis of "rational engineering decision making". Perhaps, something based on NUMBERS? Or is this yet another example of young men's (boys?) testicles taking control?
~o0o~
3. U of Melbourne - Very briefly, they moved from a four-cylinder spaceframe car in 2015, and SECOND PLACE OUTRIGHT, to a carbon-tub (new), and 500+cc-single (new), WITH A TURBO (new!), for 2016. And, no surprise, a glitch visited the engine/turbo and they scored ZERO DYNAMIC POINTS.
So, perhaps some justifiable changes on the overall concept front. But can anyone at UoM explain why their points-simulator insisted that their new concept, which entailed many big and potentially risky changes, MUST have a turbo?
How is it that your Sim-Guru missed these few lines of code in the points-sim?
IF (turbo-craps-itself) THEN
......LOSE ~500 to 625 points
...ELSE % assuming turbo ok.
......GAIN trifle points % from awesomeness of turbo-power.
......AND LOSE smidgeon points % from higher Cost and Fuel-use.
ENDIF
Based on the above addition to the Sim (perhaps done with pencil and paper), then, in the event of engine problems arising just before comp, the obvious action would be to implement THE WELL PREPARED BACKUP PLAN of "toss the turbo" (ie. turboless exhaust pipes built, non-turbo fuel map ready...).
I recall Geoff discussing their attempts to fit a turbo to their 2006+ car. Something along the lines of,
"...we found the optimum length of the turbo manifolds to be ... with the car at Silverstone ... and the turbo in the rubbish-bin back in Melbourne..."!
Z
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Originally Posted by Z
