New Parachute Design.

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AndyC

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Thought I'd share this with you all. The attached pic is a new(?) parachute design that I have come up with. Essentially it is a cone, with a extended skirt band below. A bit like the disk-gap-band 'chutes used on the recent mars-landers; more like a cone-gap band. I've tested this in sizes of 12", 18" and 24". The chute is REALLY stable, and best of all, opening-shock loads are very low indeed. Downside is that you need a bit more tube-space because of the extra fabric.
Actually very easy to make: the cone is a 3/4 circle, stitched to form a cone, the band depth is 1/3 the chute diameter, separated by a gap of approx 1/9 the chute diameter. Shroud lines are sewn across the depth of the band, with about 1" sewn onto the cone. I've used 8 shroud lines on the 12" and 18" chutes, and 12 lines on the 24". Would be interested in any thoughts on this. Has anyone done something similar before?
 

eugenefl

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Very cool! I don't know all that much about parachutes, but if it slows the rocket's descent and recovers it safely, it works for me! If you can prove it has more benefit than a traditional chute, I say go to market. Rocketeers are always looking for recovery device alternatives. Heck, sometimes just something different (with disregard to improving a current design) is good enough. Glad to see new ideas cropping up. Any actual pics of in-flight usage?
 

AndyC

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I'll sort out some photos of the actual thing, and post here soon.
Thanks for the positive remarks.

Andy.
 

Micromeister

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Pretty neat Andyc:
Have you tried attaching the band to a standard flat circular plastic or mylar canopy? This could be a bridge between fabricating true hemispherial parachutes and Flat parasheets we all use in our current models. I can see where the band may have a stablizing affect on a solid non-porous canopy material allowing the trapped air to spill out the gap more evenly. Good Idea.
 

AndyC

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Yup - I've tried it with a flat circular canopy. Worked pretty well, and was stable. The benefit of the cone appears to be softer inflation at high speeds - they inflate, rather than "popping" open.
I've tried the cone versions with and without a spill-hole at the apex, and it appeared to make very little difference - both versions showed only slight oscillation on the way down. All these tests so far have been conducted as drop-tests from a large parafoil kite, and from a moving vehicle at speeds up to 70mph. I guess actual rocket-flight behaviour could be different.

Andy.
 

Micromeister

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Sounds good.. I'll give a couple a try. I'm assuming the test chutes are rip stop nylon or porous fabric of some kind which will make a very large difference in opening characteristics.

Question about diameter to band sizing.. is the finished diameter after stiching of the cone the size used to determine 1/3 size of the band or the original flat circular dimension of the canopy before cutting?
 

vjp

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This looks a lot like the chutes being used on the M.E.R. (Mars Exploration Rover) missions.

If NASA uses this design, it's gotta be good!

The MER chutes pop when the re-entry capsule is travelling at about 1,000 MPH. Obviously the atmosphere is much thinner there, but - JEEZ!!! A thousand MPH!? Talk about pucker factor!

There's a cool video about the MER entry, descent and landing phase at

https://marsrovers.jpl.nasa.gov/gallery/video/challenges.html#edl

(Download the 'complete video' if you have the bandwidth, it's about 17MB and worth every byte)
 

AndyC

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Micromister: the ratios given are for the cut fabric BEFORE any sewing. I actually hand-sew mine, because I can get a much smaller hem. So you need to allow an ammout for hemming, etc.
However, I haven't found the exact ratio to make too much difference, so I wouldn't get hung up on it. What IS important is that the shroud lines are stitched across the whole depth of the band, as this helps maintain its shape when inflated. If you make one of these, I'd love to know how you get on. Keep us posted!!

VJP - yeah the MER was an inspiration for this, but their chutes are disk-gap-band, not cone-gap-band. It may be a scaling thing, but in the sizes that we rocketeers tend to use, the cone seems to perform better. But I guess NASA may know better.;)

Cheers,

Andy.
 

mkmilion

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I think the design rocks!!! My only question is you know how bad the drift is? I realize you testing methods we're unorthodox, but if you could guesstimate approxmately drift difference between your design, conventional chute, and streamer.
I ask because I have limited space, and I figured it's a good question. If anything bringing you ideas here first is the best trial and error I can think of for new products.
 

AndyC

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mk: - based on my observations (unscientific) the drift seems to be less than a standard flat hexagon 'chute. Don't fully understand why, as the frontal area is greater, so it should create more drift. Perhaps it's something to do with the way it vents the air around the perimeter... Not sure... I'd say its comparable to a X-form 'chute in terms of drift, but ought to be more efficient in the drag department. Glad you like it. Why not make one, and let me know your thoughts;)

Andy.
 

AndyC

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Sorry this took a while, but here's a photo of an actual prototype,in flight - not great picture quality, but I was also trying to fly the kite which dropped it!! Comments always welcome.
BTW - to answer an earlier point, the ripstop nylon is use is zero-porosity, so I guess performance would be similar for a mylar or plastic version - although attaching lines to the skirt could be awkward. I'd recommend going the nylon route.

Cheers,

Andy.
 

aksarben10

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Its not offen that you see new Parachute designs, very inventive. I would love to see more pictures of it in use and maybe some data on the drift.

Scott
 

vjp

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Originally posted by andyc
Sorry this took a while, but here's a photo of an actual prototype,in flight - not great picture quality, but I was also trying to fly the kite which dropped it!! Comments always welcome.
Nice!

Any plans to market these?
 

AndyC

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Plans to market?? To be honest, no. I've got my hands full with enough stuff at the moment. However if there's enough interest amongst you guys, I'm happy to draw up some plans and construction guides for you to make your own.
Let me know.

Cheers,

Andy.
 

Nite Builder

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andyc:
I may not be the one who will actually "make" this chute, but I think I will let a more "sewing educated" friend take a look at this because frankly, I think its an awesome design. They have made me parachutes in the past and will be quite impressed at the whole concept of this. So as for some sort of planform or blueprint......I know I'd be grateful~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>>>====> Fly High.........
 

AndyC

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Nite Builder (and anyone else). I've got a plan drawn up as a .pdf file. It's too big to post, so if you PM me with your email address,
I'll send it to you that way.

Cheers,

Andy.
 

AndyC

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To all who have emailed me asking for plans of the chute:- thanks for your interest. I'm back in my office on Monday 5th, and will send out the plans early that morning. Appreciate your patience - and can't wait to hear how you all get on with it.

Cheers,

Andy.
 

gladiator1332

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Awsome chute design. I was just doodleing some plans out today, I want to try to make a parasail-type parachute, it was just an idea so I don't think it will ever leave the drawing board. It is good to see some different types of parachutes, hey maybe if have got something really innovative there some company will contact you and want to market it...You never know!:)
 

AndyC

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Gladiator-thanks for the positive comments! (BTW - got your PM:- I'll emails you the plans on Monday - on a differnet computer).
I've also been thinking about parafoil recovery. These could be adjusted to glide in a circle to minimise drift. They are pretty tought to make. Another thought could be a parawing, like the ones Nasa develped in the Gemini programme. Take a look here npw for some inspiration.

anyhow, it's good to know that I'm not the only rocketeer who isn't satisfied with simple hexagon chutes!!

Cheers,

Andy.
 

gladiator1332

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I think sometimes that the way a rocket goes up can be just as exciting as the way it comes down. I am getting a little bored with the hexagons and it would be nice to see some new types of parachutes in the future. I think FlisKits has the greatest chance of giving us new chute designs, they already gave us some new engine mounts, so they are known for bringing out new stuff. Until then I'll have to try to make that parachute. I was happy to see your thread though, I wanted the NOVA special and saw the MER parachute and I thought, wow I would love to recover a rocket with something like that.
 
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