Hi everyone
I have read a couple of discussions on this already but it seems no one has asked about this for over a year and I wondered if there have been any advances that would make this easier since then.
So last year my school sent a weather balloon to space with a payload containing various sensors and a camera, and after a lot of searching with a yagi we managed to find it! This year we want to do something a bit more interesting, and so plan to take another balloon up with a glider, and have it autonomously glide down to a predetermined location. We have a skywalker x-5 that we've assembled and got flying, and decided on an APM. (We decided against the pixhawk because it's outside of our budget). We are ordering an neo-6m gps unit for it, and aren't sure about whether we should get an airspeed sensor or not. Should we get one? And will we need to modify any of the code to make the APM do what we want or can we just put it into RTL mode on takeoff and have it glide down once it is detached from the balloon?
Any help is greatly appreciated.
Replies
I have imagined the same project, but never attempted to do anything about it. Have you seen this video? FPV From Space. This one uses a Funjet and LRS. It was done by David Windestål who I think has also done stuff for Flight Test.
Very cool project - would love to hear how it evolves.
Another tip: Use only quality METAL gear servos. The plastic ones can freeze up and break. Metal hinges metal links and attachments.
You can just use the APM as is for a flight IF the INS does not loose it's mind on the tumble from altitude and it will start to fly around 50,000ft (change the G sensitivity)
You can set the geofence to release the plane if you don't want it to get too far away. You can use a simple dowel threw the CG of the plane and use a servo to pull a pin from the dowel to release the plane.
You can use RTL
If successful what you will get is a video with a LOT of tumbling and spinning until you get to about 50kft. The video will most likely be unwatchable until you get to the lower altitude.
The trip up is great! So that video is nice.
So if I where you I'd get a Skyfun because I know these fly fairly well. Learn how to fly it. Learn how to use the APM with it. Use the 3DR 433 radios or the RFD 900, get a good CP antenna for both ground station and plane. Forget about FPV (Unless you go for a light 5.8 ghz to use at landing and you get good enough at tracking your balloons and can be at the landing site) and just use a gopro on the plane or something similar.
If you make it back to launch you would have been very lucky with winds that day it is possible but unlikely. So be prepared to give chase!
Don't mess with the code accept that you will tumble from high altitude. And go for it!
There's a little more to it than that and that part you will learn launching balloons and retrieving them.
One last thing get you a Big Red Bee APRS tracker on 2 meters (requires a license in the US which is easy to get or have a ham friend use his) or something similar depending on where you are located.
When you loose contact with the plane via telemetry that way you can give chase and regain your signal. The new antenna tracking feature using an apm or pixhawk could work for you better but I have not tried that yet (we optically track with a telescope)
A hail Mary would be just the apm, RTL and a APRS tracker and hope for the best. You could set up an LZ in MP and perhaps do better.
Setup your plane heavy with a fast glide slope and don't try to fly until you you hit 50k and you'll have plenty of fun!
I like heavy and fast for these types of missions but you can try light and slow. Pretty much the choices. Light and slow will travel farther away. If you go light enough the wings may survive. I don't know what a X-5 is by the way.
Ahh yes one more thing the wings of the skywalker are not ridged enough. Your plane will hit at least 200mph if not more during the first part of the fall even with a parachute perhaps even more.
You need a plane with ridged wings like a skyfun or a EDF Jet.
The NTNS EDF hit 498mph on the way down.
Yeah, but in very thin air, so its not going to cause the same structural problems as flying near sea level.
That is true but at some point there will be a pull out maneuver required that will stress the heck out of the wing. Oh it has been tried with regular gliders and they always shred their wings. This was actually done way back in the 80's by a fella in Canada.
He never succeeded in the pull up maneuver. I suppose it may be possible with a drogue chute but having tried that the chute is very likely to get entangled in the plane.
There is a lot of stress as you slow down in the thicker air.
Just simplify it and use a delta. That's just my advice. But hey I'd love to see anyone try it!
Here are some highlights.
-
1
-
2
-
3
-
4
-
5
of 5 Next