Quote:
Originally Posted by groar
I have a lot of respect for all coast down testers (Darrin and all). After this experience I have even more respect. Before doing CDT with the uglyback, I'll try to find another road and a light-to-no traffic moment.
|
I wanted to talk about every people spending a lot of time to make studies, measures and data analysis, coast down and any other test.
As I said, it took me a lot of time :
- 30 minutes to drive enough to heat the car. I drove 30 miles as the road I wanted to use was too hilly and I got the wrong road to go to the one I used.
- 15 minutes for each test
- between 5 and 20 minutes between tests : stop the GPS recording, change the configuration, take a few notes and restart the recording.
- 20 minutes to drive home.
The total was 2h30. I would have liked to test the uglyback, but I need half an hour to tape it and I had only 2h available. Oops, I spent more time than I had
It seams that in the precipitation I installed a skirt less tightly than the other one so I'll have to reinstall it. If I can do other tests soon then I'll make C & D test again before doing E (D + uglyback).
About the length of the road, I simply measured it by accelerating to 110km/h and coasting to 70km/h. I was happy as at 110km/h the aero effect is important so it should be able to show a smaller difference, while I'm mainly driving at 70-80 km/h. But during last tests the road was too short and I had to break before reaching the 70km/h.
From a quick calculation, the coast down used 1.3km (0.8mi) and the acceleration (from a stop) around 0.8km (0.5mi).
I used an USB GPS receiver plugged to a computer to record my coordinates (lat, lon & alt). The GPS receiver generates a coordinate every second and it timestamps each one at micro-second. With each coordinate is also indicated the speed and the heading.
Of course I can't have the exact time at which I was exactly at 110, 100...70 km/h, so for each speed during each coast I estimated the moment by (simple linear) interpolation of time and speed between the last entry over the speed and the first entry under the speed.
Denis.