cobaltdan 0 #1 July 19, 2006 Thought this might be of interest: http://atairaerospace.com/parachutes/heli-chute/ Atair has been working on auto-rotating parachutes, both single skin and double (ram-air) for many years. We are now introducing a line of “Heli-Chutes” for low cost humanitarian airdrop (e.g. economically dropping 100 liters of water), military SOF air-drop and specialized UAV recovery applications. Why a rotating parachute? A round parachute basically has the same drag coefficient of a flat plate of the same projected area. Modern rounds are slightly higher due to some wake vortices effects, but basically rounds are in the 1.15-1.4 coefficient of drag range. And they are of course ~100% solid. A helicopter rotor by comparison is only ~4% solid (with respect the circular area it inscribes) but has a drag coefficient of ~40 ! The Atair Heli-chutes operate in a Vortex-Ring State. Helicopter pilots will be familiar with the term. As a helicopter descends vertically with increasing speed the rotor starts to enter its own wash, creating an inversion which transitions into the so called vortex ring state whereas the flow pattern is two concentric toroidal vortices extending above and below the rotor. This condition spells disaster for a helicopter pilot but in the context of our parachutes we are taking advantage of the fact that we can influence a huge air mass with very little material. The Heli-Chute has the same vertical decent rate as that of an equivalent projected area round parachute. The material and construction costs of Heli-Chutes is drastically reduced, as is pack volume ! They're real pretty in the air: Check out the video ! .Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
airtwardo 7 #2 July 19, 2006 http://atairaerospace.com/parachutes/heli-chute/ ~ If you choke a Smurf, what color does it turn? ~ Quote Share this post Link to post Share on other sites
Mostly_Harmless 0 #3 July 19, 2006 Thats heli-cool._________________________________________ www.myspace.com/termvelocity Quote Share this post Link to post Share on other sites
ripcord4 0 #4 July 19, 2006 What goes around - comes around. Someone has re-invented the wheel here. This looks just like the old Vortex Ring canopy. Is there nothing new under the sun? Quote Share this post Link to post Share on other sites
pchapman 279 #5 July 19, 2006 That's cool that someone came up with a new rotating parachute! As far as I had known, the idea had died with the old Barish Vortex Ring parachute, jumped back in the 1960s. Even with a swivel, the payload will tend to rotate. Not good for a human but irrelevant to a jug of water. While economical in terms of fabric & lines, one wonders about malfunction potential. It looks like a nightmare for partial inversion type of mals, which would then result in entanglements of all the rotating parts, as was supposedly experienced in the 60s. If only low value payloads are used, higher mal rates are acceptable. Overall delivery costs might still be minimized. 120 lbs at 22 fps at 1.5 lbs chute weight? Maybe someone has to jump a slightly enlarged version to beat the "smallest landed parachute" record... :) But I didn't design or test it, so good for Atair if they've figured out how to make it work well. Quote Share this post Link to post Share on other sites
cobaltdan 0 #6 July 19, 2006 Actually the idea was re-born when Dave Barish wandered into our factory looking to use a sewing machine!!! He had with him a portfolio of his past work, which simply is nothing short of amazing. He got me when he showed me his rotating single skin miniature parachutes designed for use on SADARM munitions. I showed him the work we had done on autorotating ram air canopies. And later when a requirement came up for an extremely low cost parachute, we decided to revisit the concept with Dave. As to deployment issues: they are so far proving out highly reliable at deployment speeds from 70 kts (helicopter) to 150kts (c130,c17)... sincrely, .Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
mdrejhon 8 #7 July 19, 2006 Actually, maple trees beat you to the heli-chute delivery system concept millions of years ago (maple seeds!) Very impressively small 1.5 pound packed volume to cargo drop that much. And even more interesting if it's the same inventor as the original concept by Dave Barish! Quote Share this post Link to post Share on other sites
FrogNog 1 #8 July 20, 2006 May I be the first to say: "I'd jump it!". -=-=-=-=- Pull. Quote Share this post Link to post Share on other sites
Chris-Ottawa 0 #9 July 20, 2006 Looks to hit pretty hard, might hurt the bones, or at the very least, your ego. Plus, you'd be damn dizzy after that! Assuming the load doesn't have some sort of a rotation limiter or something. Chris"When once you have tasted flight..." Quote Share this post Link to post Share on other sites
cobaltdan 0 #10 July 21, 2006 spinning is not an issue as the swivel works quite well. if you use a poor swivel, onel with a high tortional friction the lines twist up and the parachute falls faster. at 70kts opening shock is about 6g's, at 120kts it is about 13 g's......you would not want to jump the helichute at high speeds. with its current reefing (no slider) it is intended for cargo. .Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
