Comment by Martin Seven on March 27, 2011 at 10:32pm

There are a number of ways. Mechanical (springs, pistons, levers... actuated by servos) that are heavy and slow, natural (drogue chute positioned to open on its own when the airspeed reaches a certain level) which is dangerous because you never know when it opens, and pyrotechnic (a very small BP charge together with a commercial fireworks electronic igniter) which is by far the lightest, most reliable and safest of them all.

There are even chute designs with forced inflation - a system of weights and strings designed so that when ejected out of the chute tube it forces the parachute open, making it effective within meters from the apex of the free fall.

Comment by ARHEXA on March 27, 2011 at 10:39pm

oh no, taking explosives onboard is a step too far :D

i want to safely land my camera, not to blow it in the sky :P

the servo arm pushing it out is obvious, but i'm afraid this won't 'throw' it harsh enough (resulting in bad opening?)

Comment by Marco Glattfelder on March 28, 2011 at 2:12am

Maybe a bot off topic, but still about parachutes: I used a 36" chute on my HAB capsule. I guess I had 15-20 Km/h at impact. The landing video i here: http://www.youtube.com/watch?v=evNg1oWyfu4 

But I had 21'000m to open the parachute ;-)

Comment by I.S. on March 28, 2011 at 2:56am

@Marco

How much does the set up weight?

Comment by Nicolas Brieger on March 28, 2011 at 3:37am

Hey,

there is a dedicated, parachute-based rescue system for the german Mikrokopter that claims to open within .3 secs. It uses a pyrotechnical opening device, which is, as far as I'm concerned, the most reliable way _not_ to crash your camera. Site's in german only, so here's the google translation link: http://translate.google.com/translate?js=n&prev=_t&hl=de&am...

~Nicolas

Comment by ARHEXA on March 28, 2011 at 3:46am

pyro propulsion is probably not stupid to use.

i might go this way, it's not too complicated or expensive to make,

and it has the force like nothing else...

when you compare the german video device to a servo arm pushing a compressed parachute out of a tube, it's quite obvious....

Comment by Martin Seven on March 28, 2011 at 4:38am

Yeah, it's not explosives. It's a teeny tiny lightweight device that when commanded turns itself into about a liter of gas that can push things... out of other things. With unmatched reliability and weight.

Comment by ARHEXA on March 28, 2011 at 4:44am

Martin,

expect the blog post in a month or so about propulsion system for the parachute....

 

the thing is i'm still hesitating on which parachute to go for...

i aim for 40" (1 meter) or a bit less.

on all the rockets sites ive seen, they use 20" parachutes for max 1KG loads...

thats far of being my needs...

 

ill go though on one from a rocket store rather than a sports one, because they are made lightweight and efficient i believe

Comment by ARHEXA on March 28, 2011 at 4:51am

i'll just try to avoid this happening

http://www.youtube.com/watch?v=3arC5lVAo-Y

Comment by I.S. on March 28, 2011 at 5:17am

Cool??!! No it wasn't.

On the other hand I like this vdo because it shows what should be done:

1st stop the motors

2nd Let the drone free fall "some time" to catch some vertical speed

3rd trigger the chute

4rd cross your fingers

Comment

• ‹ Previous
• 1
• 2
• 3
• 4
• 5
• 6
• Next ›
• Page