Costyn

Very nice work Jarno! I'm all hyper again from seeing all the footage of those cool jumps. That was a lot of fun. Zeemax, the video's look different because Jarno is not using a wide angle these days. Makes for some cool looking footage. Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

I've noticed that the GPS altimeter readings are quite accurate on my ForeTrex 201 (it doesn't have a barometric altimeter). There's no wild fluctuations and especially in freefall the unit has a nice clear view of the sky so the 3D readings should be quite accurate. Of course I'm not a GPS expert and can only comment on my experiences. Seeing that TrackingDerby.com also recommends the 201, I'm guessing they came to the same conclusion. Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

Yeah, it is loud. I took my ipod mini up once, and I could hear it ok with my earphones (Sony MDR-EX71LP) during freefall. I later learnt this was really stupid (could've crashed the harddrive), but I guess I was lucky. I would like to go wireless, but I'm not gonna go out and buy another GPS just because it has wireless.

Yeah, I try to do that, but it doesn't always work. I usually try to pester the person who's sitting next to the pilot until he relinquishes his seat to me. I get pretty good coverage (8 or 9 meters accuracy) when I'm seated there. As long as you are not seated beneath the wing the gps will find a couple satellites it can latch on to. So sitting in the back near the door (of a caravan or twin otter) will work too. I've found that the shorter the interruption of signal is to the GPS unit, the longer it takes to re-acquire (up to a max of 15 seconds). If the pilot is dropping you a little further out on a wingsuit jump you can sit next to the door and have the GPS look at the sky through there while you wait for the pilot to travel his 3 NM from the dz.

Hahaha yeah it's funny how people keep on posting a link to it every couple months. Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

I've updated the GPS to SRT page with more information on how to encode the videos under various operating systems. There was little information about doing it under Windows, but I've found out VirtualDub with the VobSub plugin does the job very nicely. See the GPS to SRT page for more information. Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

Ah, ok, that's what you meant. Yes, I do add up the pieces. Hehehe yeah a GPS is a fun toy to play with indeed. However, be aware that overlaying the data on a video isn't really a trivial excercise (yet), especially encoding the video with the subtitles. Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

Cool, that should be a fun toy. We'll take a look at it tommorow. Hahaha, cool, a true hacker solution. Re-encode? Bah! Just hex edit the file. Pretty cool. I didn't know this was possible. Anyways, the original FMP4 file has been replaced with one that has the correct DX50 header ('cause it's a DivX), that people seem to be having less trouble with playing. Oh yeah btw I uploaded the same GPS track to TrackingDerby. The mileage is a little less than in the video, because TrackingDerby starts counting 15 seconds after exit. Oh and yes, it was quite windy that day. I'm not that good (yet). Cheers, Costyn. Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

Thanks! Yeah, the bearing is calculated between two consecutive points. I guess that might introduce a slight error. Hmm... that's a good point. I'm not sure how accurate the floating point numbers are, although I do the rounding only just before they are printed. The total distance is calculated with unrounded numbers. Anyways, as promised, so that everyone can play, a webpage where you can upload your GPX file and get a subtitle file with the calculations in return: GPX to SRT. I've included some notes on how I encoded it (the second time round ). Your mileage may vary. Heh, sure, I'll try. Which one do you have? Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

Hi Dave, Thanks for replacing the broken version. Apparently I needed to give an extra option so it would place the correct DivX header in the file. I also downsampled the sound some so that it became a bit smaller. Yeah, everything is in Perl. I used an XML module to read in the GPX data. The rest was just searching for the right equations on the Internet.

For everyone who couldn't get the other version to play, I've uploaded it to Google Video Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

The video was encoded using MPEG4. So you probably need the XviD codec or alternatively you can download VLC which, unlinke Windows Media Player, will play pretty much anything you throw at it (highly recommended). As for the process: the Perl script converts a GPX track file to an SRT subtitle file, which you can then give to mencoder along with the raw DV dump (or any other format for that matter) to convert to MPEG4. I'll make the perl script available for downloading once I clean it up a little. Cheers, Costyn. Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

Hi everyone, I was messing around with my GPS data today, and with the help of some Perl code to calculate values and generate a subtitle file and MPlayer's mencoder I created this video which shows various data throughout the flight: altitude, glide ratio, heading/bearing, vertical speed, horizontal speed, time, and distance covered so far. I wanted to share it with ya'll. You can find it at SkydivingMovies.com of course.

Hate to burst your bubble, but this happened in April 2002 already.

These are quite simply known as vortex generators in the aviation industry, Google it and you will see many aircraft use them. In very simple terms, the longer you can keep the flow of air along the wing before it seperates(flow seperation), the more effcient it is in producing lift. Idealy you want this seperation to be as close to the trailing edge of the wing as possible. In order to facilitate that, the use of vortice generators literaly stirs the air up to keep the energy of the air moving along the wing and prevents it from stalling at high angles of attack.The vortices created by the deflectors interact with the rest of the air moving over the wing to speed it up and help reduce the possibility of separation. The deflectors you see on the S3S and S6 are and improvement on the older design of Skyflyer deflector based on the information gained from the wind tunnel testing Birdman did awhile back. First of all, sorry for the threadjack, but this thread seems to be somewhat resolved concerning mylar inserts. I still have a question about deflectors/vortex generators, though. As you can see in this picture (photograph by Saskia Zegswaard), the 2 innermost deflectors seem to be inflated somewhat, but the rest are just sorta scrunched up and not really doing anything except creating drag, just like they are when I'm standing on the ground. I'm wondering if my deflectors are doing me any good at all. The wingsuit is an early production model (I bought it off of Jussi of Bird-Man), and perhaps they hadn't finalized the deflectors, because these are made of very tough plastic, very different from the ones that Jarno has on his suit, for example. I was thinking perhaps the suit would be better off without the deflectors, and I could take them off. What do you guys think? Cheers, Costyn. Another cool picture from that jump here. Thanks Saskia, you rock! Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

Hi Claude, Congrats on your baby! The mother and child are doing ok? Ah, ok. Yes, I see now that it stopped counting the distance at around 90 seconds. I didn't look at it that closely, I assumed my track would be disqualified, but this works too. Cheers, Costyn. Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

And what altitude is that? Wing suits usually pull higher than skydivers and some Wingsuit pilots also take it pretty low. So your pull time could differ greatly from what everyone else in the world does. If you really want to make it a fair competiton for everyone, you need to adjust the exit altitude and post the rules( safety limit/max vertical decent, etc) otherwise its just a Russian roullette for the competitors. Claude, is there actually a hard dekc? If so, it is set pretty low. I was open kinda low last weekend (think I was in the saddle around 1800), as can be seen in this track, but my track was still accepted for uploading to TrackingDerby? Cheers, Costyn. Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

Damn... very cool visuals man. I sure do wish I was there. Very cool. BTW, you took a Cessna 182 to 14000ft? How long did that take? Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

Agreed, to summarize I was just repeating what Claude had said about GPS elevation data. Sorry I guess I should've included you guy's statements about this in my summary.

Although 120 seconds is a challenge for me too from 12000 feet, I would agree with Claude that having significantly less seconds measured will make it easier for those leaving the plane at 13.5. Consider: 1 person leaves the plane at 13,5 and does a steep dive for 75 seconds and deploys at 3000ft. The steep dive gives him a lot of downward speed and forward speed, covering a lot of ground. A second person, leaves the plane at 9000 feet and does a 75 second flight, deploying at 3000 ft. This person will have covered a lot less ground and thus is still at a disadvantage. A solution to this, as was suggested by Scott, is to have an altitude range between where you measure the ground covered, much like in speed-skyidiving, where speed is measured between 9000 and 6000 feet (if I remember right). The problem with this, according to Claude is that the elevation data provided by the GPS unit is not accurate enough. So, this is problem... Decreasing the number of seconds does not level the playing field per se. Cheers, Costyn. Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

Oh yes please. I mean, I enjoy desiging and building stuff, but pointers and tips are always welcome of course. Why re-invent the wheel, I guess. Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

Uploaded......

Damn... that was quick. Yes, I did think of the forward mount, however, the camera has lots of lenses to make stuff thats closeby still in focus. Our eyes don't, and you need to place the GPS about 10cm (4 inches) from your face to be able to focus on the display. I guess you can make a construction to place the GPS there, but do you really want this thing sticking out that far from your head? It would be very vulnerable there, I think. On the other hand, Jarno placed a camera there the whole jump, so I guess maybe it would work. I'll think about making a mount for it there.

Ah, interesting, Matt. I'm sure my science teachers have probably talked about it, but I had to look it up again: http://www.chem.tamu.edu/class/fyp/mathrev/mr-sigfg.html Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

Ah! I'm finally beginning to see the light! So: if you have 2 people, one exiting at 13,5 the other at 12 and both open at 3500 and both have 90 seconds of freefall, the one exiting at 13,5 will have had a steeper angle of flight and thus probably more forward speed. This is what you mean by angles right? And the problem with using an altitude range is that the GPS altimeter is not accurate enough? Hmm... well it's a complicated issue allright.