DS in Norway and the Pike Kobra DS

[jojoen]

Hi guys!
I enjoy a lot surfing past this site now and then to get inspired for a DS session.

Here at my place I am mostly alone when I fly DS. Sadly none of the other guys in my area dares or have the thumbs to fly with me. I have a radar gun but alone it is a bit difficult to operate it ;) Sometimes my son comes along luckily. Video calculation is anyhow cool and I can atleast calculate the top turn ;)
Here are some videos from norway this summer and one old but favourite one.
Sorry I am VERY bad in German so reply in English ;)
Jo Grini
www.jojoen.no (http://www.jojoen.no)
www.jojoen.no/ds (http://www.jojoen.no/ds)


Kobra DS (not in regular production)
Calculated speed from video of the last pass 318mph (512km/h)
http://rapidshare.com/files/140080886/kobrads_300mph.wmv.html
Backup: http://www.workflow.as/jogrini/video/kobrads_300mph.wmv
http://www.workflow.as/jogrini/diary/1180kobrads/video.jpg

Kobra DS (not in regular production)
Calculated speed from video of the last pass 229mph (368km/h)
http://rapidshare.com/files/140084156/kobra_ds_229mph_080608.wmv.html
Backup: http://www.workflow.as/jogrini/video/kobra_ds_229mph_080608.wmv
http://www.workflow.as/jogrini/diary/1177kobrads/jojo_launch_s.jpg

Here is my favourite though from a couple of years back (2003) flying on the west coast:
http://rapidshare.com/files/140084624/bokn_survive_ds.wmv.html
Backup: http://193.215.54.10/jogrini/video/bokn_survive_ds.wmv
http://www.workflow.as/jogrini/diary/529bokn/ds_wmv.jpg

[Bob Hopman]

Hi there Jo!

nice to hear from you. I once visited Jo in Norway, what beautiful surroundings!! We flew some places as well as the one in the second picture.
Landings made me worry most in the beginning... landing spots over there are many times well covered with rocks, which is not the very inviting. But Jo showed how overcome this problem, there are allways some spots where the green grass rules. :D

Sorry to hear, you're still pretty much allone in the inlands of Norway practicing DS... (you shouldn't have build a F3J Supra for your son hahahahaha) I, and I think many of us, enjoy your homepage/ Diary too!

Did you ever had a good chance to compare your video meassurements with radar? Or any other speed meassurement? It would be very interresting to know, if your way of calculating the speed is accurate enough!

Keep them coming those videos ;)

BTW have you gotten news from Samba if they will try to take the Kobra back in 'small' production? I asked them a while ago, though at that time, they said, it was a one time special edition for you..

Regards,

Bob

[Artur Blömker]

Hi Jo!

Thank you for logging in and posting your very interesting news!

Wow - you´ve got a really high speed! :eek:
Nice videos - nice location!

Maybe we´ll see a new European DS Record in the near future? 300 ++++ :)
You really need a DS-team! Maybe you can fix the radar in front of the camera at the mode C ? Do you have a Prospeed?

I think a few of us are glad to hear that your 318 mph is without witness and radar ... hahaha :D:D:D

The DS-Kobra (you wrote) has ++ 3 kg - did you try ++ 4 kg? If not - may be you´ll try it? You get bigger circles, better to control at very high speed and a good penetration.

Waiting for more high speeds of you! :)

Artur

[joehighrider]

Hello Jo!

I would be very interested how the speed is calculated from the video. Can you exactly describe your method?! How do you get the single frames in one picture?

Regards,
Hannes Hochreiter

[jojoen]

Hi guys. A bit late but here I am again.

Video meassurement is a well proven method of calculating speeds. Just watch a few programs on Discovery ;)

What you need is a good camera with a fixed framespeed and a way to show frame by frame. You can even do it just by meassuring on a television set with a ruler. My camera can actually show frame by frame on the camera and take a snap shot as new pictures. Then I put them over each other and see the distance between the planes in one or several frames.
But a normal good video program can do frame by frame (quicktime can do this and then do a print screen and paste in a photo program).
Since my camera is standing still I dont need to align each picture mostly. But if I also move the camera I need to align the picture on each other (easy if you know your way around a photo program)
Since I know the frame rate (in my case 30 frames per second) and know the length of wing or fuse I can calculate time and distance.
Lets take this picture:
http://www.workflow.as/jogrini/diary/1180kobrads/last.jpg
http://www.workflow.as/jogrini/diary/1180kobrads/kobra338.jpg
When you open it in a photoprogram you get a ruler and can see the pixels
The wing on the photo is 94pixels and since I know it is 2,52m this means 94/2,52 = 37,3pixels for each meter.
Then we see that between each plane there is 188pixels / 37,3 = 5,04m for each frame. Multiplied by 30 frames = the plane moves 151,2m each second.
In kilometers an hour this is 544km/h or 338mph
Since I do several frames I go for the worst scenario or medium calculated speed so I dont say I am flying faster than I am....
did a lot of calculations not only on these frames shown. So I settled for myself that I had beaten the 300mph. Actually the calculations I did when I posted it in my diary was calculating the fuse. Not the wing.
I did some testing last winter one the ice with motor planes and my calculations are very similar to the radar.
My radar gun is an older stuff kind that needs to be held directly to the plane. Not as good as new ones. But I will try to make a stand for it to capture on video.
I dont need to prove anything other than for myself. If I would go for a record I would do a FAI record instead. But that is a lot of hassle.
I dont have ballast for the Kobra but it will be easy to make in the joiner since this LARGE Viking joiner in UMS (standard is not).
Samba feels it is too much work on the Kobra to sell it. It will have to be very expensive. The moulds are not up to date and lots of manual work.

Hopefully I can get out a soem more before the winter comes (end of november)
Regards Jojo
www.jojoen.no (http://www.jojoen.no)

[jojoen]

Oh forgot to say...
The video method calculates a passing model. While the radar needs a incoming or going away model. So checking the radar on the same object in the exact same time frame is not possible. But I had a couple of the motor guys fly past with their speed models and the speeds I got from them fly straight was very similar every time when the flew the same altitude.

[jojoen]

http://www.workflow.as/jogrini/ds/kobra_mm.jpg

[Artur Blömker]

Thanks Jo!

I post the thread in RC-Groups to inform all interested DS-fans:

"Norwegian breaks 300?"

http://www.rcgroups.com/forums/showthread.php?t=918311

Thanks Jo for your informations!

Artur

[Jaro_U]

Wow Jo, thats really really really fast!!! Congratulations to this speed!
I think you are the inofficial new European-DS-Champion!

Thanks for explaining the measurement! It seems to be very accurate!

Your Kobra must be build very well! Not very easy to get a model with a two-piece wing so stiff... It's a pity that Samba won't produce them in larger numbers.

I hope we'll hear more about you in the future! Nice to have you here in our forum! Maybe one day we can go flying together... :) :confused:

With kind regards from Germany
Jaro

[jojoen]

Thanks. Lets keep it very unofficial ;) (unless I suddenly flies together with others and with radar and video).

The model is built to my specs with
40g glass +1 layer 200g carbon + 3 layers 180g glass + 1 layer of 200g carbon. no balsa or herex. Spar is with UMS rowing (think it was Tenax 2526 but might be the mitsubichi stiffer one). The elevator is made the same way. Hingeline is with a 3mm high sikaflex (kind of a industrial silicon) Fuse is all carbon and can not be bent. Elevator is screwed on with 3 screws (actually have to beef it up even more after last session as it loosened up in the last pass).
I do have a rudder (since this is a separate mould) but I tape it when flying heavy DS.

I have room if you suddenly find the urge. Lots of DS sites here but most you need to walk. The one I use is only 400m of walking and if I walk 200m back to the car I can land on very soft ground.

Regards Jojo

[Dietmar]

Hi,

I also thought about new ways of measurement when my radar gun got to its limit. Also I don't like (Hannes) flying to close to use exactly in our direction. And btw. I can't fly the track I want because I have to fly against the radar gun, so I fly mostly a triangle instead a circle or ellipse.

The most important things when measuring speed by video I think are:
- Camera is not allowed to move (also not by wind).
- Autofocus must be switched off (does often change scale factor)
- the calibration must be done in the same direction the airplane goes, because if the wing is not paralell it looks smalle and the estimated speed gets to high.
But the airplane should fly paralell to the camera, so the calibration should be done again from pic to pic, because if the angle gets mor parallell by time the calculated speed is to high.

By rough calculation I got to a speed of:


http://www.dynamic-soaring.de/forum/attachment.php?attachmentid=537&stc=1&d=1220471124

If I get the high res pictures I might try to do a more precise calculation by a special software.

greatings

Dietmar

PS.: next time I will take a second camera with me (16:9) to compare the two methods.

[jojoen]

Today it was nice conditions with 6-10m/s winds and thermals passing thru. Set my old fashioned radar up and did get a few passes with the radar and could calculate also the bottom turn just a second or so before the radar reading. The radar reading on this pass was 110 and 106mph (it started with 110 and went down to 106 passing). Calculating showed a very similar speed though it was small pixels (far away on the bottom turn).
I also got 237mph on the radar gun as top speed of the day. Lots of video to go thru to find the right pass that gave that value. I had huge problems getting the numbers to show up on the video since the sun was into the display and it is a LED display. Most speeds today was around 120-140mph and my son worked the radar a lot but got tired after a while (he is 11years old). So I mounted it on a pole so he could lay in the grass and just follow it.
p1040972 1:28 106mph
14pxs between back elev to front wing = 14/0,9 = 15,55
25pxs between each model = 25/15,55= 1,607 *30frames = 48,23m/sec
= 107mph = 172k/h
http://www.workflow.as/jogrini/diary/1200kobra/P1040997_orig_cut.jpg
http://www.workflow.as/jogrini/diary/1200kobra/P1040997_all.jpg
http://www.workflow.as/jogrini/diary/1200kobra/radar_237.jpg

The model is built to my specs with
40g glass +1 layer 200g carbon + 3 layers 180g glass + 1 layer of 200g carbon. no balsa or herex. Spar is with UMS rowing (think it was Tenax 2526 but might be the mitsubichi stiffer one). The elevator is made the same way. Hingeline is with a 3mm high sikaflex (kind of a industrial silicon) Fuse is all carbon and can not be bent. Elevator is screwed on with 3 screws (actually have to beef it up even more after last session as it loosened up in the last pass).
I do have a rudder (since this is a separate mould) but I tape it when flying heavy DS.
I guess if enough demand is made Samba will consider. I am their friend and their webmaster... Have been working with them for many years.

[jojoen]

Found a superb DS slope on the north west coast and thought I would share the find. Looking forward to test this slope in higher winds (probably not before march/april).

http://www.workflow.as/jogrini/video/skolten_ds.wmv (48mb .wmv)

http://www.workflow.as/jogrini/diary/1223molde/video_s.jpg

[flowmotion]

Hi Jojo,

very nice video !!!!
Thank you!
The spot is great and should shoot you to a very high speed!

Hannes

[Bob Hopman]

Hi there Jo!

a really nice video worth looking at! Nice site to fly too ;)
Long trip to get there, but surely with high potential!

Looking forward for March/ April....

Regards,

Bob

[Jaro_U]

Hi Joe,

thank you for posting this video!
I like it! Nice flying and good cut!

The spot looks great! I wish you strong wind and good luck for the next time!

Kind regards from Germany!
Jaro

[jojoen]

Thanks guys! Cant wait to get there again.
Off to a smaller slope tomorrow or in the weekend. In the mood for DS now and the slopes in my area is not possible to access :(