PetriL - 25-3-2011 at 03:45 AM
Hello all,
Yesterday we had a quite windy (and super gusty) day here in Finland and some records were broken? I'll list here the data I have and also leave links
to original files. You can then speculate if my calculations are correct.
I was on skis and had a LF Envy 2011 7m2 kite, wind was ~15-16m/s and gusts somewhere 25m/s. Data logger was a Ventus G730 and as a back up I had
another logger also. I do realize that I don't own a GT31 logger so all results are more or less "valid".
First link includes filtered data from my gps, filtered means that I've taken off all accelerations over 4m/s2. Second link has been calculated with
trapeze setting on and last with doppler setting. Software I used was GPSAR Pro:
http://toaster.fi/~Frk/KiteSpeed/24_3_2011_filtered.html
http://toaster.fi/~Frk/KiteSpeed/24_3_2011_filtered_trapeze....
http://toaster.fi/~Frk/KiteSpeed/24_3_2011_filtered_doppler....
As far as I've understood, my device doesn't support doppler and results are too (in)accurate in that sense? From KA72 I got results http://www.ka72.com/TrackRecalc.aspx?fid=13041 which are a bit different from GPSAR calculations but still in the same line.
Original files are at: http://toaster.fi/~Frk/KiteSpeed/data/
24_3_2011.gpx file is exported from gps logger via GPSBabel and those others starting with W are from Nokia Sportstracker (+external bt gps receiver).
That Sportstracker data is filtered already
in software so it's not that accurate and there no doppler support at all. There are multiple files because I have to shut down logging if wan't to
see max speeds during session.
Here's also a short clip from a one "show off"
http://www.youtube.com/watch?v=Pp3GKisvABc
So, how fast can we go?
-Pete
PetriL - 25-3-2011 at 07:23 AM
After I removed all speed values from gpx-file and uploaded it to ka72 (so calculations are made based on trackpoints, not doppler), following results
came up:http://www.ka72.com/TrackRecalc.aspx?fid=13050
65.5 knots = 75,37 mph = 121,3 km/h are the ~same as in other calculations.
Comments?
edit: mph was wrong.
PrairieWind - 27-3-2011 at 02:26 PM
My only comment is if it takes that much work to prove how fast you are then you might want to get whatever certified gps gear is needed at those
speeds instead of all manner of calculations and machinations... .
I'm thinking you spent more time working out the speed stuff online than actually kiting. (A sin). I'm sure you are fast dude, just let Rachel
decide if you get your Dakine Beanie or not (or whatever the reward of the week is!).
g-force junkie - 27-3-2011 at 04:54 PM
PetriL
That's haulin a*# by anybody's standards, good job!
krumly - 27-3-2011 at 05:49 PM
PetriL - by the look of the YouTube video, you were hauling a$$.
Prairie Wind - you could back off a bit. PetriL is new to the forum. The device he's using is a GPS logger without a display (BTW, it looks like a
pretty cool device). My guess is the devices we're all more familiar with are using some sort of algorithm to smooth the discrete data points to give
us an 'average peaS-P-A-M-L-I-N-K- over some duration, however short, to determine the max speed we see on the display. PetriL is presenting several
of those scenarios. Don't fault him for being a gear head. Maybe some speed freaks like Chris Krug on skis or Arjen on the buggy might weigh in. On
one level you are correct: If you want to set some sort of record, find out what the requirements are to have it recognized and measure accordingly.
krumly
thanson2001ok - 27-3-2011 at 06:45 PM
That was screaming fast.
I have never flown that fast. Forgive the naive question. How do you stop when you are doing those speeds?
snowspider - 27-3-2011 at 09:01 PM
I like how your video shows you preparing for your run then dropping the kite into the power and just locking it level , beautiful ! That feeling of
acceleration is addicting.
PetriL - 27-3-2011 at 11:10 PM
Thanks for the comments!
For me going fast has been just a fun thing to do, and suddenly I realize that I'm going pretty fast. But again, to be able to compare data, all
should have the same device and use same software to calculate results. That whole "max speed" is questionable anyways, in my opinion official ranks
should be based on 5x10s average or something else more realiable way of measuring. More correct places for rankings are at gps-speedsurfing etc.,
these forums just give you an opportunity to share your experiences.
PrairieWind, don't worry, I spend more time to kiting than writing to forums. Those results are made while laying in a sofa and having couple beers
after great sessions. And for the beanies or wallets, I don't need those 
krumly, you're correct about the devices, very few device can provide "raw data" to be analyzed. One of those is the "official" GT31 which I don't
own. Then again, to prove record results should I have 2 of those devices? That Ventus is really a good and inexpensive device and accuracy is enough
for me at the moment. Just put it on and check data after sessions.
thanson2001ok, just spot 100-150 meters of free space, full depower and FULL BRAKES 
snowspider - 28-3-2011 at 07:09 AM
For those of us who dont have brakes(aka kite sled) its look and plan way out front , full depower , maybe raise the kite maybe not , steer up wind.
Still scratching at the 50mph door.
PrairieWind - 28-3-2011 at 08:02 AM
It's great when the wind / surface / and kite size all come together for some blazing speeds. I think I was just a little grumpy yesterday morning
when the wind speed at my spot was a big fat ZERO. Sorry if my comment was offside - I guess I didn't realize the type of GPS gizmo you were dealing
with. The beanie comment was meant to be funny, since I know that you have to produce the raw files for speeds over 60 for the stormboarding stuff.
g-force junkie - 29-3-2011 at 04:57 PM
PetriL
Would love to know what ski's you were riding, you were holding a wicked edge on less than perfect surface, I could use a set of those for our less
than perfect conditions.
PetriL - 29-3-2011 at 10:06 PM
For speed riding I use my old racing skis, K2 Comp 190cm, from year -93 or something. Maybe best picture of those is here http://www.flickr.com/photos/karri3nen/5512264001/in/set-721... 
Before each
speed session I sharpen the egdes to get maximum grip. Normally I ride with Atomic Pimp twin tip skis.