This is the spot for ballooning. Share your stuff here.
Earl
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This is the spot for ballooning. Share your stuff here.
Earl
You need to be a member of diydrones to add comments!
Replies
What we have here is a collision of design philosophies :-)
Good-natured, well-meaning and constructive, I hope.
Foamy's are cheap and expendable...in my opinion. If they are big-in-size and low-in-density, they should be able to absorb any shock that could damage instruments. This is common practise with the "rocket guys." The best HPR-type rockets only fly a few times. Frangibility (I think that is the right term) is built into the design to save instruments and lives and video cameras. Data and cool pictures rule!!! Even with parachutes, HPR-type rockets are so damaged by super-sonic flight, they can only be re-built and re-flown a couple of times. The main reason for a parachute is to prevent the rocket from breaking stuff and killing people when it lands.
-peter
If the over-all mass of the "foamy" is low-enough, a parachute may not be necessary....just design-or-allow the "foamy" to absorb the impact...that means sacrificing the aircraft in a way that saves your instruments....or shift the center of gravity so the foamy become unstable and floats to earth for the last 100 feet-or-so. Also, I wonder if a steamer could be used here?
-peter
That's an interesting idea, Monroe....using a "ring" on a round parachute that performs the EXACT same function of a "slider" on a square parachute. Murphy's Law say that unless you have some way vent and inflate a round parachute, the "ring" might prevent the parachute "skirt" from swallowing enough air to inflate the parachute. And you'll have what parachutist-over-50 call a "streamer." AGAIN, test this "ring" idea under the same conditions of aircraft flight when its parachute is deployed. The rocket guys use "sleeves" on their round parachutes, the same as was used by skydivers of the 1970's.
Instead of using masking tape as Monroe suggests, I would stow the cord using very light rubber bands. Masking tape...even gaffer tape....can roll-up-and-bind into a "rope," making it impossible to break. If you do use masking tape, DO NOT wrap it around the lines. Instead, find a way to use the tape to gently tack-down the lines. Better still, find a rigger over 50-or-60 who can remember and demonstrate how to pack-and-stow the lines of round parachutes using rubber bands, as was done with parachutes like the Para-Commander ;-)
I'm showing my age :-(
-peter
Hi Nicolas,
I think you are on the right track with the ejection system: A VERY small amount of FFF-G (gun powered) in an "air bag" will eject a properly packed and stowed parachute. The question is this: how fast will your craft be traveling when the chute is deployed?
When you say "rocketry guys," I assume you mean a group like the Tripoli Rocketry Association. The High Powered (model) Rocketry members of Tripoli do have a lot of experience with high-speed, parachute opening. However, they keep using parachute recovery methods that are meant for slow, model rocket-type openings.
If you attend a Tripoli launch and watch the really experience guys launch and recover their scale models, you will notice that most time, their round parachutes will blow a panel, or shred, or the Nylon or Kevlar "riser" connecting the chute to the rocket will cut through the rocket body like a "hot knife through butter."
Case in point: See Steve Eve's (link) launch (link 2) of his 1/10 scale model of the Saturn 5 (link 3). Notice how the riser, or shock cord, cut through the rocket body. (see 4 minute mark for close-up - link 4) Steve's rocket opened at apogee, the SLOWEST part of the flight, and yet the riser still cut-through a very solid rocket body. The "anti-tangling" device can help slow the opening and prevent the aircraft from being ripped apart from the open shock.
Can I suggest visiting a couple of the larger skydiving centers and consult several certified riggers, with a B or C license? In your case, the parachute deployment MUST be made gradual, or in stages, or the risers will rip the mooring from the aircraft, if the aircraft is traveling more than 200 mph when the ejection charge goes-off. A pilot chute, or sleeve, or bag is used by skydivers to delay or soften the open shock of their parachutes: something that is essential for any craft (or human) traveling more than 150 mph when the chute is deployed. Conversely, if the craft is traveling less than 50 mph when the chute is deployed, a staged deployment is NOT desirable.
Have you tested your balloon-launched aircraft recovery system at lower altitudes, like 5000 feet or less, where you can observe your design in action, and are more likely to recover most of the parts. It will cost more, but, if you can capture the opening with a min-cam or GoPro, you'll learn more about what works, or doesn't work.
-peter
I was looking for a description for the parachute harness, container and method of deploying the the pilot chute or ballute so your bird doesn't end-up with a tangled mess? Have you considered enlisting the help of a certified rigger who has experience packing for high-speed HALO or BASE openings? -peter
Hi folks,
I want to introduce my balloon based high altitude UAV. The construction is compact, lightweight and low budget but includes full 9 DoF IMU, GPS, pitot tube, barometer, VGA-camera, 20dbm transceiver and so on. For landing it is equipped with a parachute. Some more details you can find on the project blog. Current step is to realize the parachute ejection.
Pleace let me now your suggestions!
Nicolas
Earl -
Did the plane end up going where you told it? How did you solve activating the servo's at the right time?
I am trying to get everything together for a launch, using APM2.5. No APRS, just a modified cell phone for recovery(sends SMS of location).
Thanks. Lincoln
On high altitude balloon projects to avoid Arduino flight computer failures due to outside systems, for example, cutdown, communications, or sensor controllers from getting stuck in a subroutine, watchdog timer within Task Scheduler for Arduino will reset the flight computer. Source: Hack a Day
Hi Earl! What 433MHz amplifier did you use with you 433 3DR radio?
Best of lucks! :)
Hi Monroe . . . no team, just me with a strong interest in citizen science via balloons, e.g., mapping & ionizing radiation, etc - enjoy the relative minimalism. Nice to make a connection. CHEERS! Mike
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