Comments on WSCTube.com: Solar car safety & crashes analysis

Unicore Inspire's roll bar, shorty helmet, an...

2010-11-05T21:54:54.086+01:00

Unicore Inspire's roll bar, shorty helmet, and lack of padding provide limited protection from either a violent rollover or debris intrusion. A line drawn from the underside of the apparently missing roll bar padding, to the cross-brace immediately forward of the steering wheel, bisects the driver's head. Also missing is an expected front roll hoop over the steering wheel. Per WSC thinking, perhaps that cross-brace is considered to serve the purpose. It doesn't.

WSC doesn't make a distinction between old 1995 helmet standards and more recent ones, but there are distinctions. [1] Although there have been improved Snell standards every 5 years, i.e. 1995, 2000, 2005 and 2010, even for 2011 WSC says the "1995 Snell/DOT/ISO motorcycle" standard is acceptable.[1] Hardly cutting-edge. Addressing safety is not so simple as picking or forming standards and leaving it at that.

At least 2" of air space between any part of the helmet to the padding should be required, with the driver properly strapped in - no crunching down allowed. WSC accepts even zero clearance between the top of the helmet and a line drawn from the tops, not bottoms, of a rear and forward roll bar[2]! Combined with the aforementioned "crunching down" tactic drivers may use to pass scrutineering, it should be no surprise if a driver is not well encased within the solar car during a crash.

No head restraint or fire suit seems to be used on the car, and the safety harness seems narrower than the minimum 3" I'd expect would be required.

It's frightful to think of the result of solar cars being creamed by other road-going traffic, when the carnage shown is what happens when solar cars land in the bush seemingly all on their own.

Umicore Inspire's roll bar design is intriguing as a minimalist approach, but driver protection is inadequate. UofMI's approach to driver ensconcement could be similarly criticized.

Sites such as [3]LaJoie's and [4]Simpson's may supply ideas on safety improvements.

Umicore's suspension and steering response to conditions seem to have been abysmal, yet in an article posted before and after the race it was said of it, through development software sponsor LMS, [5]"virtual testing was very promising and during the test drives, the car showed very stable and efficient behavior on the road." really?
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-brian

If you penaltize tyre changes, teams will probably...

2010-10-17T10:54:00.275+02:00

If you penaltize tyre changes, teams will probably use tyres that last longer than the ones currently being used. This also reduces the risk of tyre blowouts and thus make the event safer. The tyre choice is a tradeoff between low resistance and durability; teams usually select the ones to finish in shortest possible time. So it is not uncommon to completely wear out multiple tyre sets in one race.

A lot is discussed about this and other topics in the WSC groups at http://tech.groups.yahoo.com/group/wsc/ e.g. in the "Michelin 16 / 65-80" message thread starting from #2935.

Yeah, official regulations are to be obeyed of course, but the problem is that some regulations are not written precisely enough (e.g. safety aspects and the state of the car during scrutineering), which gives room for different interpretations and such.

I've never attended the NASC personally, and I think I'd better not write something serious about things I don't know about, so no NASC crashes are discussed in this article. Maybe someone else is interested in writing about this? But the only ones that have all original/official crash information is the organization of the event itself - and unfortunately they never make such matters public.

Just curious, why should teams that change tires b...

2010-10-16T03:10:02.548+02:00

Just curious, why should teams that change tires be penalize? How would that improve safety? You mentioned that the suggestions have been stated elsewhere, could you provide some sources?

"It's just psychologically difficult to t...

2010-10-12T20:10:31.994+02:00

"It's just psychologically difficult to take a car out of competition, because a team worked so hard on it and would have to wait two years for the next WSC! (I mean this especially about the not-so-precisely-written regulations)"

Regulations are created for the specific purpose of taking "psychological difficulty" out of determining what's fair and safe. Without enforcement, regulations are useless and the event becomes fundamentally unfair and unsafe. This is a basic aspect of running a professional racing event. I hope that the Global Green Challenge is ready to pick it up.

A bit more info on the Michigan brake system. Whil...

2010-10-12T19:29:25.165+02:00

A bit more info on the Michigan brake system. While ASC has since updated the regulations to prohibit the type of mechanical brakes used on Continuum - downhill mountain bike disc brakes - at the time they were legal and quite common. Most importantly, they were fully capable of locking all three wheels in an emergency stop - in other words, they achieved the maximum braking force possible given the tires and configuration. Really the main issue with the brakes, which became an issue in ASC 2008, was durability - the pads could wear out over the course of a race and needed to be maintained diligently. The stopping distance wasn't great, but was comparable to a large, loaded van - there are many road-legal vehicles with less braking authority.

The 2007 crash then, can be primarily ascribed to error on the part of the drivers of the solar car and caravan vehicles - a too-close following distance exacerbated by traffic congestion (it's amazing how many regular drivers will cut off a solar car, leading to defensive driving too close to your support), coupled with a slow reaction time. The accident occurred just as the team was proceeding through a recently turned green traffic light, at which point a Stanford caravan vehicle braked hard (they were separated from their solar car, and just located it). The Michigan lead car also braked hard. To the solar car and chase van, the braking of the lead car was not immediately apparent as an emergency stop, slowing reaction time. The compressed traffic situation and high-stress environment resulted in a rear-ender. By law, the solar car driver is "at-fault", but this situation is hardly unique to solar car and happens all the time in city traffic. Not a failure of the design or regulations, in my opinion.

The only regulation issue I have is that Stanford was allowed to leave the start line without its support cars - while Stanford is not at fault, their driving certainly contributed to a dangerous situation, and would have been a non-issue if the written start line regulations had been followed by race officials.

A couple of things I noticed: 1) note how many of the failures are due to tire failure or poor suspension design. Many of these accidents appear to be caused by marginal steering stability (you should not lose control due to a flat, and even willy-willies (dust devils) are manageable - Michigan's Continuum drove through several without incident) These appear to be the major mechanical causes of solar car accidents, and should probably be the main focus of any regulation updates. 2) Apart from the death of the Toronto driver, no major injuries have resulted. Given the visual severity of some of the crashes, the safety of solar cars in one vehicle and low-speed multi-vehicle crashes is remarkable - compare these crashes to the expected result of a similar motorcycle crash, for example.

Thanks for compiling this database - it's interesting stuff. I think there are some more North American incidents which would be worth looking at, some of which fall into the "driver error" rather than mechanical categories - one team, I think Stanford, rear-ended their solar car with their chase van and damaged some panels, for example, and I think several teams have had non-crash spin outs in rainy situations.

Thanks again for the comments! I've added an u...

2010-06-27T16:35:23.292+02:00

Thanks again for the comments! I've added an update to the information about Michigan's crash.

It's just psychologically difficult to take a car out of competition, because a team worked so hard on it and would have to wait two years for the next WSC! (I mean this especially about the not-so-precisely-written regulations)

"It is of course very difficult for the organ...

2010-06-27T04:29:52.687+02:00

"It is of course very difficult for the organization to actually take a car out of competition (at scrutineering or qualification) after a problem with regulations."

Why is that difficult? If the race will be taking safety (and itself) more seriously, I hope they're ready to enforce the regulations.

Michigan's 2007 car had mechanical braking on ...

2010-06-27T04:22:48.999+02:00

Michigan's 2007 car had mechanical braking on all three wheels. That should be corrected in this report.

Recalling Michigan's car required a (poor) red...

2010-05-21T20:54:02.605+02:00

Recalling Michigan's car required a (poor) redesign for the brake lever during ASC 2008. It appeared to me some of their drivers couldn't grip hard enough to stop the car during dynamics testing. The team stuck a piece of copper pipe over the handle (yeah quick thinking,but not a pretty design for a $2.2 million dollar car). I also recall their master brake cylinder leaking, they had a spare, but it was in ITALY! (great project management skills) I watched one of Michigan's driver's breakdown during qualifying laps due to the team's pressure to drive the car (poor/uncomfortable seating postion didn't help her nerves) and the officials required the team to get another backup driver (which I think drove in Australia). If you look back at the 2007 end or rayce video of Michigan in Australia, they show a scene where they are doing the brake test... Michigan's car doesn't stop.. it goes off the screen. The team then managed to rear-end their lead car just minutes off the start line. They tried to blame Stanford, but the root cause was poor brakes and following too close- again poor seating position didn't help along with the fact the driver had to take his hand off the steering wheel to reach forward and grap the brake lever... Then you have Michigan running thru traffic lights in the middle of 2008 rayce - why: they had worn thru their brake pads (really meant for a mountain bike) and the officials gave them a HUGE time penalty. If I was the driver, I'd refuse to get in that car. Thus there is the new "Michigan Rule" for brake pad area. I believe Michigan managed to run their car off the road and thru a barbed wire fence during a test drive prior to NASC 2003- maybe their team can tell us why.

From what I've read about all these solar cars, sure Nuon has wrecked more, but it appears Michigan has been the most negligent when it comes to design. 95- magnesium (light but not a very tough material) wheels with bad stress conentration radi, and 2001 car couldn't even complete the figure 8 test. So would you hire an engineer that couldn't master the basics?

The rollbar design of Umicore (and of all other pa...

2010-04-24T14:00:47.974+02:00

The rollbar design of Umicore (and of all other participating cars) conform to the regulations stated in http://www.globalgreenchallenge.com.au/assets/pdfs/wsc/2009.technical.regulations.pdf which implies that the driver's head doesn't hit the ground when the car flips over on a flat surface.

In the photo at http://www.solarteam.be/node/1167#767 the driver probably wasn't in normal driving position, I think (or it is the camera's perspective).

How do you mean that you can't practice a tyre blowout? Driving over road spikes on purpose in a well-protected (testing) solarcar would do the job :)

I think most crashes which are due to blown tyres,...

2010-04-13T23:40:19.873+02:00

I think most crashes which are due to blown tyres, may actually be driver induced. This is a situation you can't practice, so perhaps drivers didn't respond to this well enough. There's never a way to check this though.

And a rollbar is ment to protect the driver's ...

2010-04-13T23:36:23.014+02:00

And a rollbar is ment to protect the driver's head when the car flips over. Judging from your Umicore image on this site, if the car would have flipped during the crash, the driver's head would be severely hurt (it sticks out over the roll bar).

Continuum's steering wheel had the brakes buil...

2010-02-11T01:38:14.803+01:00

Continuum's steering wheel had the brakes built in, such that you did not have to remove a hand from the steering wheel. The steering wheel was quite beefy and had no problem handling the required forces.

Glad to have helpful people here! I didn't kn...

2010-01-18T11:17:27.766+01:00

Glad to have helpful people here!

I didn't know about hand-operated brakes in Continuum. Maybe this team member can tell us more about it: http://tinyurl.com/yzrkaek

Are there more teams (besides Twente&Nuon) which had troubles with adhesive joints?

One other note: Apogee was Stanford's 2009 ent...

2010-01-17T20:28:26.420+01:00

One other note: Apogee was Stanford's 2009 entry, I believe their 2007 entry that crashed was "Equinox".

About Michigan's 2007 car: I may be wrong, but...

2010-01-17T19:45:01.515+01:00

About Michigan's 2007 car: I may be wrong, but the impression that I got when we raced them at NASC in 2008 was that all of the controls: brakes, throttle, etc, are hand-operated. There was a pot on the steering wheel for throttle and a bicycle/motorcycle -style hand brake next to the steering wheel. So yes, while that seating position looks terrible, legs falling asleep doesn't really constitute a safety issue.

Having to take a hand off the steering wheel to grab the brakes, well...

Whoops, I watched http://video.canvas.be/solar-rac...

2010-01-17T15:25:28.382+01:00

Whoops, I watched http://video.canvas.be/solar-race-australie-afl-2-analyse-van-de-crash (at 0:12) with my lenses inside out. The rollbar is indeed still there. I've corrected it, thx :)

"The sleek rollbar of Umicar Inspire broke of...

2010-01-17T15:03:58.595+01:00

"The sleek rollbar of Umicar Inspire broke off in the big crash"
I'm sorry to inform you this is not correct, the rollbar was not harmed what so ever. And it was designed to withstand a force of 4g.
I do agree with the underlying message of your post. The average speed of the solar cars should go down to increase safety of the GCC.

Thx, I've adjusted it!

2010-01-13T12:41:24.934+01:00

Thx, I've adjusted it!

"The team later explained that the damper of ...

2010-01-13T12:20:30.097+01:00

"The team later explained that the damper of the rear-whaal suspension system was probably not tuned correctly" is a statement of the Umicore team and not of the team from twente.