Marc's Public Blog - Cars

Clearly, since I overdrove my tires last time, I tried to be more mindful of their temperatures, and I just didn't drive them as hard. As a result, I barely managed a best time (for the 4.3 mile track) of 3:14 instead of 3:13 my last time there. Also I was just tired and not doing that well that day, so I guess there was no reason to push it unnecessarily.

Early sunrise flight to Willows

interesting way to water fields

Cool cars as usual:

back for more, full of bugs :)

competition was fierce :)

Although I was super tired, I did a 30mn RC flight around lunchtime to get some nice shots of thunderhill from low altitude. You should go to my RC flying Thunderhill 6 years later page, for more pictures and video.

On the flight back to PAO, I got extended very deep into Moffett. I could easily have landed there :)

my bigger power glider barely fits in my car :)

it's a bit snug though :)

2.6 meter wingspan

Around lunchtime, I went for a 30mn flight around the track (easy to stay up with minimal power use due to the gliding capabilities). You can see videos (front and rear) and some screenshots below (synchronized version courtesy of viewsync)

someone had fun doing donuts :)

Here is a virtual lap of thunderhill (although my RC plane took more than 3:14 to do the lap I did in my car :) ):

turn 2

turn 3

turn 5 and bypass

turn 6

I was impressed in the length of the protective tire wall before 8

8 looks benign from here

turn 9E doesn't look uphill from here, but we were taking the fork to TH West

Turn 9C is an interesting roller coaster, but you can't see it from here

what's interesting is how I've never even seen the 2W connector when driving by off camber and trying to get back to the right of the track

a rear view showing 2W

3W is an interesting turn where I'm braking hard and steering at the same time so that I can make 4W

I also never noticed that tire wall to protect people driving on the highway from being hit by an out of control car

5W is usually not a big deal

here it's easy to see the shortcut at 7W we were taking

the normal 7W hairpin is tough, but we were taking the straight instead

the new 7W shortcut is very inviting from this angle :) You also catch a bit of air at the 10W connector

10W connector from another angle

again, seen from the rear camera

rear straight with 1W

1W isn't too bad

funny how I've never seen 2W because I was so focussed on not messing up 10C

the conection back to the east track is very downhill and off camber, always scares me a bit :)

I didn't even know this access road to the west track was here

11 and 12

12

I like driving over this bit :)

14

15

It was fun to get a few shots of the cars that were doing drag racing:

I never noticed those numbers to setup cars on the front straight

I had never seen the cell phone tower at the top of turn 1 until now:

Some shots of the paddocks, many solar panels:

that was just after takeoff

I was piloting from the shade under the pro shop

skid pad

just before landing, crow flaps deployed

I was looking forward to this since I was pretty sure I had gotten faster in my last day, but had no point of refrence on that new track, and wanted to see how I'd do on the original track.
In the morning we were running the bypass and I got down to a 1:56 on one lap (and several laps at 1:57). That's beating my best time ever by a whole 2 seconds on half worn (good) street tires, yeah! The best view is this viewsync video showing front and rear at the same time (i.e. follow the link), or you can have just front and rear non synchronized (in 4K goodness should that be needed :) ):

Sadly, it seems that I was indeed pushing the car and those tires a bit beyond what they could do. The tires got too hot according to my tire pressure sensor, and as those things always go, I got serious understeer in turn 8 and was not able to complete the turn.
I went straight out to avoid problems, but sadly once out I chose to turn right a bit instead of turning left which had me go over some nasty bumps. I may have done this out of memory of the bad ditches that used to be just next to the track (and where people used to flip), but aren't there anymore.
The underside of the car suffered from jumping and landing over those bumps, although nothing major, but the shocks got a bit unhappy from landing while being on their harshes (least travel) setting, and all 4 accumulators need to be replaced (basically they got fluid pressure from the landing that wasn't dampened by the shocks since they were in race mode). The repair bill won't be too major though and thankfully no damage to the bodywork or front of the car.

Of course, I wanted to know how I managed to do this, and thanks to the video and the GPS track, I was able to determine that:

turnin point is almost the same with almost the same speed, and initial turn angle is the same

the tire doesn't look horrible, but I guess it was probably low(er?) on grip

I also reviewed the tire temperatures, and that's probably a good clue of something wrong

The video does show that I start turning left and just flinch the wheel to the right a tiny bit as a response to a bump probably, and then continue my left turn. However, by then even though I am slowing down still, I'm just getting understeer. I checked afterwards and my front outside tire was pretty worn (not bare, but worn) and apparently was low on grip.
Nico told me that 233F is way too hot for a tire, especially a street tire, so that could explain how I ended up in an understeer situation that was non recoverable.

The best view is this viewsync video showing front and rear at the same time (i.e. follow the link), or you can have just front and rear non synchronized (in 4K goodness should that be needed :) ):

There is some damage to the underside of the car, but it may not be worse than what you'd get from hitting rocks and/or bottoming out on a bumpy road (which incidently happened to me just 10 days prior). I'll know for sure when I get the car back from service.

Anyway, this is a bit vexing of course, but looking at it another way it's my first real out at thunderhill in 12 years or so, so it's not too bad looking at it that way.

During lunch I swapped the front rear tire after removing the weeds and pebbles that were inside my car :) and when the track re-opened I got to do a few laps on the track with the cyclone, the real 3 mile track. Just before getting an error about shock failure, I got a 1:59 which definitely has sentimental value to me since I had never ever broken 2:00 on the original 3 mile track.
So all in all, despite the off, it wasn't a bad day.

I guess it could have been a lot worse

After a few laps in the afternoon, I had to come out because a shock accumulator that popped and caused this fluid leak

A few pictures from others:

Arnaud and his new car

plenty of colorful porches