You are currently viewing archive for August 2010
Category: Racing Simulators
Posted by: Mike
I'm at my Mom's this weekend and was bored so I decided to take a quick crack at Grand Prix Legends. Grand Prix Legends is a racing sim from 1998, simulating the 1967 F1 Season. It was highly regarded at the time and had a huge following in the sim racing community.

I hadn't played it at all since I started playing iRacing over a year ago. I used my old non force feedback Logitech Wingman Formula GP wheel. I played this game for six or seven years, and although it was pretty sparingly and I never put in that many hours or raced competitively online, I thought I still had a grasp of it. I was wondering if I could improve my times since between iRacing and real world racing, I have a much greater understanding of what the hell I am doing now. But I was in for a surprise! I crashed the Lotus 100 feet after pulling out of the pits at Watkins Glen! It was a challenge to just drive straight down the straightaway! The handling is very touchy, especially with the non force feedback wheel and cheap pedals.

After a few laps and a few crashes, I did actually start to get a hang of it though. But after running 26 laps, my best time in the Lotus at Watkins Glen was 1:08.5, over 1.7 seconds off my personal best of 1:06.77 I set in May 2007. I don't think I'll ever improve on my GPL Rank again. Although I think I could improve it I put in ALOT of time, it's just not worth it anymore. Looks like my dreams of a negative handicap are done!
Category: General
Posted by: Mike
A few months ago I bought the My Tach GPS Sport Trainer watch from AIM for use as a primitive data acquisition system for karts, track days and SCCA racing. I'll say it is nice tool to have and well worth the money for me.

There are four main measures that the My Tach logs that are helpful for racing applications - position, speed, longitudinal acceleration and latitudinal acceleration. It also logs slope (I think that's degree of elevation change) which might be marginally helpful and heading is of no use from what I can tell.

I've used the My Tach several times at outdoor kart tracks in arrive and drive karts and also for a trackday event. Be sure to check whether you are allowed to use a GPS timer or data logger with the organizers of the trackday, although from my experience, it is not always clear what is allowed. It's also the perfect tool to have if rules dictate you cannot have a data acquisition system plugged into the cars electronics (such as SCCA showroom stock).

The tricky part to using the My Tach is setting the starting "point" to get laptimes. Basically, you just press a button on the watch to set the point wherever you are. On the kart track, I was able to run out onto the track to set this. If you aren't able to do this, you'll have to set it on a warm up or cool down lap. Also note it is a starting "point," so if you are too far off from that point, such as if you are passing someone, you may miss the point and that laptime won't count. I set the starting point in a corner and haven't had a problem like that yet. Otherwise, you just press the start button before you go out and the stop button when you are done. I don't bother to look at the little screen for laptimes while I am driving, and wouldn't advise you to do this; I use it strictly as a logger and download and analyze the data afterwords.

Analyzing the data isn't quite as simple though. The watch attaches to a dock which is connected to a computer through a standard USB, but the raw data is downloaded in a proprietary format (although there is an option to save it in CSV format within the AIM software) and must be downloaded into the Aim Sports Agenda software or the Aim Race Studio Software. If your already familiar with the AIM software that's great, but if you're not, it's not the most user friendly, although I can manage with it. The Sports Agenda is a simplified version of the Race Studio software designed more for other sports such as running or cycling, but the interface 95% the same. If you've never looked at any data acquisition before, it may take some time to draw any meaningful conclusions form the data (I'm definitely still learning), but I do definitely think it can help. That said, I wouldn't expect to pick up huge chunks of time, especially from just a few measures (no throttle position or braking force, etc.) Some of the things the software allows you to do are plot speed and acceleration vs time, view GPS position data, overlay laps on top of each other, and plot the time gap between two laps over time. Below is a screenshot of the Race Studio software with an overlay of two laps run in rental karts at the Summit Point Kart track.

The My Tach samples at 10 hz, which is fast enough to produce reasonable data with the 110-115MPH top speeds I was seeing in the Spec Rx-7 on Summit Point main. The GPS position is precise enough to see variations in cornering line between different laps on a kart track. One neat feature is the GPS data can be exported into kml data to overlay onto google earth images. Below is an example of this which shows the precision of the GPS.

The My Tach attaches to your wrist like a watch although it is pretty bulky, bigger then most gps sports watches designed for running I've seen but it works. The casing is plastic and not too heavy and the buttons and interface are easy enough to use.
I've also used it a few times for running and it's a cool tool to have for that too, although I haven't used comperable units designed specifically for running to compare.

Feel free to ask me any questions I didn't cover.