2015 FSAE Rules

[Alumni]

Someone throw Z the life preserver. He's really gone off the deep end this time!

As far as the turbo discussion I do have to agree with Jay that there will be an increase in thermal events, but probably not by much. There will be, as MBirt eludes to, a number of teams undertaking a turbo attempt that have no business doing so, simply to jump on board. And at early September planning meetings, a turbo now makes a lot of sense. This will result in one or two turbos or engines spitting bearings and connecting rods out through previously non-existent holes in their engines, which almost always leads to an oil fire.

With that said, Bob, I agree that in order to be a top five team such as yourself a turbo will be practically a necessity (sidenote: it'll be interesting to see how the Europeans fair at MIS this year with these and the aero changes...) As you drop below the top few teams, reliability is increasingly driving factor between, and a turbo adds a lot of complexity and weight to a car. I do not see them as being necessary to compete with "the best of the rest" such as at FSAE West or smaller competitions.

As far as ETC, it should have been implemented years ago. Unfortunately, the rules committee and their fear of unknowns at that time can be better explained via Simpsons meme than another mindless forum rant.
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Luckily things seem to be changing. Slowly.

[Charles Kaneb]

I'm fine with most of these rules, but I'd REALLY rather not see unsprung aero go away for three reasons.

1) Banning it eliminates your most difficult first-day design decision. There are very few half-measures - either unsprung aero is a primary feature of your car and other systems were designed around it, or it isn't and you don't have it. Can you get enough additional performance out of an unsprung system to justify the rest of the compromises to the car?

2) Unsprung aero is only legal here. There's no "canned" design solution available. You cannot modify an IndyCar, F1, LeMans wing and mounting type to suit the scale and use of the car if you go unsprung. Therefore, if it's on the car and it works, you designed it, or you reverse-engineered it from another FSAE car with nothing to go on but photos.

3) The cars aren't fast enough yet. Unsprung aero gives an avenue for making one a lot (multiple seconds/lap) faster if you can make practice match initial calculations. The SCCA Solo PAX index for FSAE is 0.989, for a K-mod it's 0.957, for an A-Modified it's 1.000 A 2013 FSAE car is expected to be 1.1% slower (one second per lap or so) than an A-Modified car and 3% faster (2 1/2 seconds per lap) faster than an SCCA-legal kart. If we do something that slows FSAE cars down by 3% between 2013 and 2015, they will be slower than a kart that is 1) Ballasted way up to 385 lbs 2) Not first-line equipment (CRG Bad Boy, TonyKart Racer EVK, or equivalent, powered by a Swedetech CR125 or a 2010-homogolation KZ2 shifter engine and 3) Driven by someone who won't win SuperNationals. These cars are expensive ($25,000+) and take a lot of student effort (5000+ hours) to design and build. What they get in return should be able to beat throwing a dart at the eKartingNews classifieds.

[Z]

I'm not sure what your complaint about the bigger engines is ... as you state the restrictor already provides a limit.

Kev,

And that is exactly my point. Why bother with any engine-capacity limit at all? Just scrap it. Make the Rule book thinner. Save some trees...

But for reasons to do with low self-esteem, the RC Members only ever want to make the Rule Book longer. This is a bit like blokes with small, err, "members", wanting to drive high-powered cars with long bonnets. (I will retract that last statement when any RC Member provides any reason at all why a RESTRICTED big-block V8 might have any advantage in FSAE, or otherwise be too dangerous because of its "awesome" power.)
~o0o~

Also by Kev.
... the big difference between the electric motors and petrol is not the peak power, but the sustained power. An electric car limited to 80kw will be able to do this through-out their rev range by the rules, meaning incredible torque down low...

Technically correct, but IRRELEVANT to the Acceleration event. So WRONG, WRONG, WRONG!!!

Sorry Kev, but I have spent the last decade+++ bashing my head against a wall in frustration over this. Please do not take personal offence, be patient, and read on...
~~~~~o0o~~~~~

Head-banging rage building... Internal pressures reaching critical... Stand back, boys and girls...

(I have selectively rearranged the following quotes to better make the point. What follows is not directed soley at Dunk, but at ALL OF YOU, because you are all making the same STUPID MISTAKES!)

Originally posted by Dunk on this thread, and also the FSUK Comp thread:

... I don't agree that 2wd is better than 4wd for accel. ... if the cars are breaking traction, and the coefficient of friction cannot be increased (short of cu$tom tyre compounds), then the only way to accelerate off the line faster is to drive all 4 wheels.

... biasing all the mass to the rear of the car to maximise traction on the rear tyres, will not only make the cars impossible to control but also just darn terrible in every other event.

Maybe a [combustion] car designed purely for acceleration could keep up with the standard e-cars, i.e. a dragster that meet the regulations. But that car would suffer in every other event, and would not beat a electric dragster. The issue being torque curves, dropping power to shift gear 2 or 3 times [blah, blah...]...

Copying last years car is an industry standard, because well it works. It means ... the problems [are] easy to solve.

But starting from the ground up with students who don't really know what they are doing and haven't got a clue ... is just going to [fail]...

Is it possible for the best combustion car to outperform the best electric car in acceleration under the current rules? ... doubtful ... a insurmountable amount of work for a bunch of inexperienced students to have to do in the space of 10 months.

The above sentiments, shared by almost all FSAEers, are proof positive of just how far down the S-bend the Education system has flushed the lot of you.

The emboldened sections are PURE, UNADULTERATED, CODSWALLOP!!! The fact that the vast majority of you FSAEers BLINDLY accept such BRAIN-DEAD "explanations-cum-excuses" is a DISGRACE.

I accept that a small part of the blame for YOUR STUPIDITY can be laid at the feet of your current teachers. When your current University teachers refuse to teach you the most basic elements of Mechanics, then, yes, there is a skerrick of an excuse for you to keep making the same STUPID MISTAKES.

But you have been doing it non-stop, over and over, for 30 years! By contrast, the Toothless-Hillbillies don't have any teachers at all, other than each other. And they keep going faster and faster, non-stop, year after year.

Your generation call yourselves the "interconnected" (or "networked", or whatever...) generation. You have Google. But have any of you ever used it, for this particular problem? CLEARLY NOT! Otherwise you would not make the STUPID sort of comments above. INCREDIBLY, BLEEDING, STOOOPID!!! And BONE-IDLE LAZY, too! You cannot blame your current teachers for your own laziness.

So, what is the root cause of all this STUPIDITY?

It is ALL THE TEACHERS you have had since Kindergarten. They have brainwashed you into believing that "There are no wrong answers. All opinions are equally valid. Yes! That way every one of you darling little kiddies can get a Gold Star!"

The end result of a decade and a half of such CLAPTRAP is that none of you have to think about anything. None of you have to learn anything. None of you will ever question the emboldened quotes above (which, I repeat, are pure BULLDUST, and obviously so!). And all of you can be content just "copying last year's car", because that way the "problems are easy to solve", and you are assured of getting that Gold Star. (And here the GS is simply having "FSAE" on your CV - "Sure, the car never turned a wheel, but I are an FSAEer!".)

There are a few students who question the above stupidity, and are prepared to put in the hard work seeking the correct answers. Unfortunately for them, they are vastly outnumbered by the zombie hordes of IMBECILES who are chasing their bonus Gold Star by shouting out "Look at me! I have an opinion! I think we should keep doing the same STUPID things we did last year. And I won't give a single good reason why...".

Even more unfortunately, the philosophy of mindlessly "copying last year's" whatever ultimately takes you all down the crapper. Very rarely there might be some small, random, improvement. Much, much, more often there is degeneration in the "copying" process (look up entropy).

The degenerative changes that result from this "mindless copying" of society's accumulated knowledge are now so bad that I know of legions of Emeritus Professors who are nowadays metaphorically teaching Flat-Earth Theory - "Oh yes, it's supported by four huge elephants, all standing on an even bigger turtle. All done in 6 days back in 4004 BC. And I can prove it. Look, its in these books!"

I feel very sorry for all your children, and the world they will inherit.
~~~~~o0o~~~~~

Should any of you want to show that you are NOT as STUPID as I say, then here is a quick quiz. All the answers are available on these pages (I have been spelling them out since 2005). So a Pass mark requires a perfect score.

Q1. Explain how the car's "power" and "grip" influence the Acceleration event. Specifically, which is more important at different stages of the event.

Q2. For a car with a given maximum power, why is the "launch" phase the most important for low times? (The THs know this, and call it "hooking up", or some such...)

Q3. Why is RWD-ONLY better than 4WD for a good launch? (The Mechanics of this are simple, but since they require knowledge of "rotational quantities" I am confident you will all fail.)

Q4. Explain the differences between Formula-5000 and Formula-Ford racecars in terms of their power, mass-distribution, and tyre-sizes, and how these differences affect the two cars' relative performances on the circuits they race on. (Note that neither of these cars is a "dragster", and their type of racing demands that they go around corners as fast as possible. Like in FSAE S-P, AutoX, and Enduro.)

Q5. Explain why the vast majority of FSAEers have more closely copied the general layout of F-Ford, rather than F-5000. (There is only one correct answer here, and that is that said FSAEers are LAZY IMBECILES).

Z

(PS. Dunk, again, not directed soley at you, but at ALL of you...)

(PPS. Pressure still near critical. Better go for a walk... )

[Swiftus]

We would still be limited to the same power limit due to the restrictor

I disagree. A supercharger or electrically driven turbocharger would allow an engine to continue to compress air into the plenum further down the line during any part throttle event (most likely more than 50% of an FSAE course). That mass which is stored is then used during the full throttle events. If the course is transient enough and the plenum large enough, then power is effectively unlimited.

The engine only needs to last for ~45 minutes, so turn the boost up to 11 and, partnered with Electronics throttles, auto-drive your 600hp FSAE around the track. I'm sure that car would win every event by enough of a margin that the economy wouldn't matter.

[Swiftus]

(1)Jay, we see this often as the price of admission is lowered. Carbon fiber becomes increasingly more available: more suspension points pull out of tubs during the brake test. Giant wings become almost mandatory to win under wide-open aero rules: more wings fall off during endurance, more cars crash due to aero balance issues that weren't sorted in design or testing. And so on.

(2)...no major issues other than a cracked exhaust manifold weld after the 100 mile endurance....(3)they just weren't highly visible like the one thermal event-prone example of late you're probably thinking of.

Cool! I like this discussion! How about a couple of counterpoints?

(1) I agree that as tech becomes cheaper, it becomes more common which means more mistakes can be seen. However, unlike all of the failures you mention, a failure in a turbocharged system means unpredictability with moving parts and explosive fluids at 1100C.

(2) Pre or post turbo? And does a snowmobile in CSC compete in the snow during winter?

(3) I have seen two very thermal events in the last three competitions I have attended, plus additional minor thermal events in the previous four events. I would not consider it uncommon and to see how common failures are with the big teams, imagine the catastrophe of the smaller teams joining in. Who wants to work all year to end up with a smoldering pile of tubing?

[Kevin Hayward]

Z,

Both power and grip are important in the acceleration event, no one disagrees with you that the launch phase is the most important. It does not mean that increased power does not contribute to the overall time. This is true in the very powerful drag cars that are traction limited for around the first half of a pass. I am also aware that good times can still be had from drag cars even getting off the throttle at the half track mark. The other important thing to note is the more we improve grip, the more important power becomes for decreasing accel time.

We have a number of drag racing guys as students. One of whom is the crew chief for one of Australia's top teams. I also agree that we have a lot to learn from the drag racing guys.

Likewise I agree with your points about rear mass distribution. When we made the move in 2003 (UWA) to much more rear weight it was seen as the wrong path with just about every other team eschewing a 50-50 weight balance. In fact calcs support quite a lot more rear weight even with the same size tyres front and rear (60-65% with appropriate suspension changes). Changing relative tyres sizes and you could go much further, making RWD the way to go, with a car able to do well in all circumstances.

In this case power still matters, more so than before, because grip has improved.

The big problem with going down that path is getting all the weight to the rear. If we say that a top level FSAE car is 140-150kg. On average a driver will weigh about 80kg with all gear. Of that weight 50% will be below the navel. Lower body weighs significantly more than upper due to lungs and dense leg bones. This means the drivers legs will push the weight forward a lot. This has been made worse with the chassis length rules.

We want the engine and driver as close together and as rearwards as possible. You would probably agree that this means not having double wishbones at the rear. It also probably means hanging the engine out the back 911 style. Achievable, but has some packaging considerations. The newest ECU car tries push the weight further rearwards than before, including a live rear end. Unfortunately for the weight balance a lot of weight was saved out of the powertrain, but very little from the driver. So despite the wheel centreline and the driver being a lot closer together than in the past the rear weight (with driver) is still only 56%. Without the driver the rear weight percentage is huge. A rear hanging engine was considered, but wasn't implemented at this time, for a number of reasons. A lot of which could be revised later.

One of the big issues for these cars is having enough yaw acceleration. To this end close to minimum wheelbase was chosen. Extending the wheelbase out to 1700mm would take the rear weight bias to around 60%. Which is better but still far from making your case work.

Getting a larger car such as a F5000 to have a much more rearwards weight bias is a lot easier mainly due to the fact that the powertrain is much heavier than the driver and the cars are longer. The driver is a small proportion of length and weight.

There are car configurations that make your assumptions work reasonably well, but they almost defintiely involve powertrains currently unused in FSAE, as well as a vastly different car architecture. Not implementing these is not just a case of laziness. These students have only a starting knowledge in maybe a couple of areas. Teams consist of a large number of students that didn't grasp a lot of the engineering mechanics. Maybe somewhat because of bad teaching, but also because they didn't go to all classes, or work hard on their knowledge. In designing a car they are finally finding out why that knowledge was important.

The pace of improvement in FSAE is slow, with high student turnover, poor knowledge retention, and conservative design being the primary cause. But overall the cars are moving towards more go-karts. In 2003 (reference year for the UWA car mentioned above) the norm for top cars was:

- Weigh ~230kg
- 4 cylinders (with around 60hp)
- 50% rear weight
- 1750mm wheelbase
- 1200mm track
- No downforce
- 13" wheels and tyres
- Almost universal double a-arms and rockers
- Mountain bike shocks

Now the picture is signifcantly different
- ~160kg
- Single cylinder (around 60hp - fours with around 85hp)
- 55-57% rear weight
- 1530mm wheelbase
- 1100mm track
- ~100kg at 70km/h downforce
- 10" wheels and tires
- Much reduced unsprung and rotating mass
- Purpose built shocks

The typical Formula ford design of the rear suspension mounting significantly rearwards of the powertrain is almost unseen near the top. A lot of focus of teams has moved away from mid-corner ultimate grip towards initial turn in and increasing yaw acceleration. Understanding of the physics behind the cars is slowly improving. The questions asked now in design are significantly harder and more involved than 10 years ago. Any student that goes into a design event now with a 2d understanding of 4 bar linkages, a lack of data analysis, and no effective team management structure will be crucified. The loop is being closed as ex-top students start to fill the judging roles. Nothing bores them more than seeing the same stuff being done now as what was done 10 years ago.

More importantly we are seeing more teams playing around with different powertrains, and drive methods. More teams looking at alternative suspension mechanisms. More teams playing with smaller different tyres and so on. We are heading towards the go-kart slowly but surely. This work isn't being done by the majority of the teams, but I think that just mirrors the wider engineering community. One of the big issues here is that it is difficult for teams to look past the short term pain for long term gain (especially considering they will not be the students benefiting from the work). For example the ECU car this year was a massive re-design of all systems, with some pretty large conceptual changes. Some you will like, some you wont. Things did not go smoothly at the recent UK comp. Some of the new systems had some teething problems, and students were doing a lot of different types of work that they had very little experience with. An unlucky problem right after the team arrived in the UK, ended up causing problems that dogged the team the whole way through.

By making a lot of changes at once there was increased risk. The question is was it acceptable risk? The previous car would have outperformed the newer car at the same competition, purely by being a more developed machine (a polished turd compared to a rough-cut diamond). But the new car has much more potential. A lot of the people that took that risk, will not be there if it comes good. Was that a good strategy? The points on the board say no, only future development might reverse that.

Lastly when looking at simulated evolution we see some funny things:

- Improvement is almost never purely linear
- Evolution is slow and fast. There are spikes of improvement, but there can also be long periods of stagnation
- Ultimately it is mutation, not combination that moves the performance of a population (these random improvements that you mention)
- There is a difference between genotypes and phenotypes. The outward display of the genes does not necessarily represent their inward design. With respect to FSAE that could mean that the future "best" FSAE team at the moment does not look like it could be the best, likewise the teams currently winning, might have deep structural flaws. Same goes with the cars.
- Selection is based largely on Phenotype. Teams try to copy another, but do not replicate the underlying ideas (genotype) causing a flawed copy. Similarly less judgement is made on the inner properties. It is not difficult to imagine people ignoring the good designs of an otherwise poor vehicle.
- A population average can improve without the best solution improving. For example given enough time the seemingly worse solutions may overtake the current best.
- Changes to the environment will change the population. We cannot underestimate the effect that rule changes have on disrupting the improvement in performance.

I would say we could very clearly see this process occuring in FSAE, in both the teams and cars we see. When you see entropy, I see evolution. It is an inefficient method of utilising all of the resources of all of the teams to move towards a global optimum, but it is probably better than the alternative.

To avoid getting stuck in local minima it is important to increase variability (mutation). Commenters like you can help with that (although it would be nice if it was with less acid), overly strong selective pressure (i.e. too much focus on final performance) will encourage local minima. Given that the greatest pressure comes from the score-line and prizes and reputation rewarded accordingly there is a great pressure to stay in the local minima. For example when we see the reports of the events, almost all of the focus is on the winning teams, and almost no focus on the innovative concepts.

I think the best way to help teams move towards the global minima is to encourage a population that is more focused on genotype than phenotype. What is the make-up of the car, not the final result. To call them lazy is wrong, teams are just organisms responding to external pressures encouraging local optimisation.

Kev

[Tim.Wright]

[Dunk Mckay]

I'm hurt, Z, very hurt. Just kidding, I fully agree with you on the education side of things. I skipped most of my lectures in my final 2 years of uni, preferring to educate myself on the relevant subjects. Yet somehow I still got a 1st class degree. Just a shame I had to pay a lot of money for it, and that a load of other people I wouldn't want to work with in a million years also got the same qualification. The issue for me, I guess, was that I was still reading from the same books as everyone else, more or less, as that's all there is to read.

Due to this, I don't expect to do very well, but I'll play your game, for now...

Q1. Explain how the car's "power" and "grip" influence the Acceleration event. Specifically, which is more important at different stages of the event.

Based on my observations of wheel spin on launching I have to say that cars are low on grip in the early stages, so this is the limiting factor, not power.
Further down the course the rate of acceleration is dropping so the engine is struggling to overcome the drag and inertia, i.e. it is lacking in power.

Q2. For a car with a given maximum power, why is the "launch" phase the most important for low times? (The THs know this, and call it "hooking up", or some such...)

For a given maximum power there is a given top speed. Reducing the overall time along a straight means increasing the average speed, this means reducing the time it takes to get to top speed. (an oversimplification FSAE cars rarely reach "top speed" over 75m, but they start to plateau and the overall principal applies).
I'm getting my thoughts muddled, not being a powertrain guy. But power and torque curves probably come into it. The quicker you can get the car up to a speed where the engine speeds being used are such that maximum power/torque are being sent to the wheels the better. So the more efficient the launch, the quicker you can get some real power down.

Q3. Why is RWD-ONLY better than 4WD for a good launch? (The Mechanics of this are simple, but since they require knowledge of "rotational quantities" I am confident you will all fail.)

I'm still going to say that F=ma, and that force is the product of normal load and the coefficient of friction. and the best way to maximise that force is by spreading your traction across 4 wheels. The only downside to this being that it invariably increases m, but probably not by as much as it increases F.
There is also load transfer to the rear wheels, dictated by numerous factors, susp geometry, CoG height, etc. Which will increase the normal load on the rear contact patches. Shifting the mass of the car rearwards in it's design will also do this.
But assuming that a 4wd system weighs the same as a 2wd system, all else being equal, unless you car is doing a wheely of the line (i.e. dragster) then there is still more traction to be had from the front wheels. In fact I would hope that there is still some traction on the front wheels otherwise you driver will have no control, and with uneven driveshafts and imperfect components a guarantee, torque steer is going to spin the car into a wall, like this guy: http://www.youtube.com/watch?v=kh1uE4jdxh4 (still no excuses for ruining a perfectly good helmet though).

Q4. Explain the differences between Formula-5000 and Formula-Ford racecars in terms of their power, mass-distribution, and tyre-sizes, and how these differences affect the two cars' relative performances on the circuits they race on. (Note that neither of these cars is a "dragster", and their type of racing demands that they go around corners as fast as possible. Like in FSAE S-P, AutoX, and Enduro.)

I'm going to skip this because it has been covered by someone more knowledgeable on the subject that I.

Q5. Explain why the vast majority of FSAEers have more closely copied the general layout of F-Ford, rather than F-5000. (There is only one correct answer here, and that is that said FSAEers are LAZY IMBECILES).

Rhetorical?
Lazy? No, well some of them maybe. Some are scared or lack confidence in their own abilities. Others know the limits of their own abilities which aren't great. Others have the ability but don't have the time. Others have the ability and the time but no one to support them. Some even have the abilities and the support, but that support completely lacks in ability and one man can't design and build a racecar all on their own, not in the allocated time anyway. (I use the term ability here to encompass experience, knowledge, skills, or the capability to acquire said qualities.

So to some extent yes, you're right people in FSAE are what you call 'stupid', some of them, a significant portion of them perhaps. I've helped manage a team of 30-40 "engineers" and as I said above there is a good portion of them that I would not want to work with in future. And of the hundred or so people that I met doing FSAE at my university during my time there, there are probably only 20-odd that I would ask for help if I was given the task of recruiting a team to design and build a really good FSAE car.

[Mbirt]

Cool! I like this discussion! How about a couple of counterpoints?

(1) I agree that as tech becomes cheaper, it becomes more common which means more mistakes can be seen. However, unlike all of the failures you mention, a failure in a turbocharged system means unpredictability with moving parts and explosive fluids at 1100C.

(2) Pre or post turbo? And does a snowmobile in CSC compete in the snow during winter?

(3) I have seen two very thermal events in the last three competitions I have attended, plus additional minor thermal events in the previous four events. I would not consider it uncommon and to see how common failures are with the big teams, imagine the catastrophe of the smaller teams joining in. Who wants to work all year to end up with a smoldering pile of tubing?

1. An 1100 C EGT would be a sign that that team should not be running a turbocharger: "I can just keep retarding the timing and adding fuel, right?" Custom dry systems have been allowed for years and have dumped plenty of oil on tracks and exhaust systems. Student-built fuel systems are almost always in close proximity to the exhaust system. I don't think you can say that turbo oil plumbing is an order of magnitude more dangerous than student-built dry sump systems and fuel systems.

2. Pre-turbo, at the turbine inlet flange. We finished the endurance and the crack could have been repaired without penalty under FSAE rules. At CSC there is a 100 point no maintenance "bonus" that you lose when you break a serial-coded hood seal to make a repair to the vehicle. We had to fix the crack/leak to comply with the rules of the lab emissions test.

Snowmobiles at CSC do in fact operate on snow, on public trails, in a dyno lab at peak power speed WOT for 2 minutes, and are even ridden by competition judges for a subjective handling event. That should make FSAE safety folks cringe considering the fully enclosed bodywork, turbochargers, and catalysts, but SAE manages to get the event insured (the same organizers handle FSAE) and no one debates whether or not students should be allowed to innovate with boosting concepts.

3. Big team does not equal good powertrain sub-team. Small teams that venture into turbocharging without a thorough points analysis or thorough development of the rest of the car have probably already done so. I often tried to stay abreast with what these teams were doing in previous years, became excited to see them at competition, and was eventually let down when they arrived naturally aspirated.

Contrary to what Dr. Paasch and you believe, turbocharging will not become mandatory to win the competition. Well-tested and well-driven cars will continue to win. A second-tier team might crash the party with solid design, acceleration, and fuel economy scores, but it's no reason for teams at the top to be concerned.

I disagree. A supercharger or electrically driven turbocharger would allow an engine to continue to compress air into the plenum further down the line during any part throttle event (most likely more than 50% of an FSAE course). That mass which is stored is then used during the full throttle events. If the course is transient enough and the plenum large enough, then power is effectively unlimited.

Your capacitive overboost/compressor surge theory giving any team a huge advantage is a bit ridiculous and the plenum size limit will attempt to keep this in check if anyone does attempt it. If a team does figure this out, more power to them (pun intended)! It would still not be able to achieve the same average power of an 80 kW e-car.

[Swiftus]

1. 1100C in a turbocharged system is precisely my point. EGTs that high should not exist around turbochargers, but it is very easy to do. Maybe a team cuts spark for their rev limiter. Maybe a team placed the turbo too close to the cylinder head so it takes just a very small amount of unburned fuel to greatly increase the EGTs. Maybe the team did everything right except they have poorly atomized fuel? Without a huge amount of testing and knowledge, it can be very difficult to make all of the mistakes and design a good solution. The current rules set helps a team make that effort distinction right away.

2. The failure at a weld next to the large bending load makes sense for why it failed there.

How enclosed are the snowmobiles? If they are anything like I've see in the mountains, than the engine exposure is a little less than an ATV.

My point, as you correctly inferred, is that snowmobile engines are in front of the rider and are somewhat exposed. Formula engines are behind the driver (typically) and are enclosed. Which is partly why it can be so difficult to cool Formula cars with the 'stock' cooling system from the bike.

...to be continued...Boarding an airplane.