Відео

but air density is also much lower! so there's less absolute drag force (Newtons), and thus higher speeds are possible/needed for gliding with the same L/D ratios (so that lift ~= weight). if airspeed >> wind speed were kinda safe

Exactly! at 30km altitude we usually fly at 80m/s ground speed, around 10km altitude, as you mentioned the windspeed is usually very high and the flight speed lower, so we mostly descend vertically. Most of the return distance is done between 20 and 30km altitude

Please read the description again. 10 of the flights we did this summer were with MeteoSwiss from their launch site in Payerne literally launching within military airspace. Autorities know the system and have confirmed it fits in the same category as conventional radiosondes.

@@YohanHadji I have to deal with the FAA here.

Well, we also got confirmation from the FAA that the system would also be considered as a standard radiosonde in the US

@@YohanHadjiI think when you release the plane, you will be in no-man’s land because it becomes a UAS..

No, FAA confirmed that it doesn't become a UAS after release.

Usually 70 to 80m/s, sometime up to 130m/s of groundspeed after release at 30km altitude!

@@YohanHadji 130m/s its about 400-500km/h. I see the wing is covered with thin carbon rods. IMHO the wing would have collapsed at 150kmh

@@unixoid33 thin atmosphere so less problems?

@@vidmasze ok maybe, but on low altitude?

I never said we're flying at 130m/s at ground level! We only fly that fast at super high altitude, the groundspeed at ground level is between 10 and 20m/s.

We usually have around 70-80m/s of groundspeed at 30km altitude and have already reached 130m/s at 33km altitude!

yeah the ascent is done with a weather balloon!

yes it's giued by GPS

Without being blasted with music.

Hey! Most Ublox GPS modules available today work perfectly fine up to 50km altitude and sometime even 80km altitude as long as you choose the "airborne < 4G" navigation filter in the settings.

good eyes!

Weather balloon !

Just to make it clear the video is in x20 speed starting from a few seconds before 1:15 hahah but I think I see what you mean anyway. Yeah stability is hard, a bit harder with a huge camera (relative to the size of the glider) on the tail too. This launch isn't from Payerne but we have done 10 launches from and back to Payerne a few weeks ago with the support of MeteoSwiss! If you live in the eastern part of Switzerland and like building electronics you might help us by setting up a small ground station capable of receiving the telemetry of the glider. Every now and then we have a small issue with small gliders and having multiple ground stations would help with getting as much data as possible to recover them. Let me know if this sounds exciting (you can get in touch via the form on the website: https:r2ho.me or maybe ytb is sharing my email somewhere)

@@YohanHadji Ah, I missed the part that is is 20x speed. Still, you should get rid of the oscilations.... So, where was the launch from?

​@@ronaldglider20min away from Lausanne

@@YohanHadji Ah, so I see lake Leman

Peut être que je peux aider, on a des bonnes antennes 2.4GHz à cheseaux!

the avionics doing the guidance is custom, on most days, you can't use the standard RTH procedure from existing software such as ardupilot/Px4 to return from the stratosphere to a precise landing point

@@YohanHadji Nice, it is really impressive how close it returns to you

> you can't use the standard RTH procedure from existing software such as ardupilot/Px4 to return from the stratosphere to a precise landing point do you mean doing to "routing", finding the better/safer path to fly? or in general? ​@@YohanHadji hmm my guess would be that with minor modifications Ardupilot should likely work (didn't test), e.g.: scaling of cruise/minimum speeds depending on air density/height (if doesn't exist already), configuring for proper gliding (prefer fixed airspeed with differing AoA, over fixed AoA and differing throttle -> should exist in soaring code, there's a setting). There's also Lua scripts to modify some Ardu behaviour (or raspberrypi over mavlink). no sure just about cheap airspeed sensor reliability at such heights. What I'd worry about would be stall-spin recovery, due to baloon/line/aiplane spinning during launch @YohanHadji did you experience any? without a rudder might be not easy to recover, and I doubt Ardu has/had code for that.

maybe because there are two gliders hahah! That was the whole point of the video but I feel like no one actually got it.. :'-(

​@@YohanHadji No I actually did think that but I thought there was no way! That is insane man, really impressive.

Please tell us

​@@johninyorkit's all autonomous with custom avionics running the guidance code and uses a GPS for position input yes

@@YohanHadjivery cool 👍🏼

who said that hahha?

@@YohanHadji well, 30km altitude and glide ratio 1:20 gets you there

@@ronaldglider We can only dream of 20:1. Reynolds is a git!

@@markpitts5194 Well, I fly gliders from time to time with 1:50 What do you mean by *git?*

Ohhh I wish we had 1:20 lol. Glide ratio is much lower on a glider with a 90cm wingspan haha

Yes

No the avionics doing guidance is custom

Could you do a video on the avionics? Like did you make the software yourself?

Yes software is custom, to be honest, not sure that video will exist in the short term, it would take way too much effort compared to just putting some music on the raw flight footage and I don't have that much time to spare but maybe I change my mind in the coming months!

Tout est automatique!

When I retire in a few years I'm going to do this

radiosondy.info/sonde_archive.php?sondenumber=U0510118Y radiosondy.info/sonde_archive.php?sondenumber=U3510394Z radiosondy.info/sonde_archive.php?sondenumber=U3510387 radiosondy.info/sonde_archive.php?sondenumber=U3524360