Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!samsung!uunet!comp.vuw.ac.nz!canterbury!otago.ac.nz!klox
From: klox@otago.ac.nz
Newsgroups: rec.skydiving
Subject: Re: Differences between parachutes and paraglider
Message-ID: <1991May3.164623.358@otago.ac.nz>
Date: 3 May 91 05:17:21 GMT
References: <6435@qip.UUCP> <1991May1.212459.776@husc3.harvard.edu>
Organization: University of Otago, Dunedin, New Zealand
Lines: 66

In article <1991May1.212459.776@husc3.harvard.edu>, galperin@husc9.harvard.edu (Gregory Galperin) writes:

> 	But since they hadn't just been in freefall for a mile ( ;-), a couple 
> of minutes under canopy on the way down didn't provide enough excitement.  So
> they started using larger and larger canopies, with more and more cells...
> all the time looking enviously at hang glider pilots above them.  The designs
> grew in wingspan and area continually, and many paragliders are now over
> 40 ft. in wingspan and 450 sq. ft. in area, with a large aspect ratio.  The

Aspect ratios of around 4:1 are now common

> resulting airfoil is something like a ram-air sailplane (i.e., parachute +
> glider = ...), and flies something like a hang glider (or so I've been told,
> at least).  The chord length tapers off severely at the ends, and the last
> few cells are closed in front (they have no ram-air port, only cross-ports),
> and curve down like stabilizers.

Some also have winglet fins above the top surface. Some are ported only on
the wing undersurface, not leading edge (= less drag)

> 	It's true that the materials used in paragliders are generally less
> porous than those in skydiving canopies (although it's hard to get less
> porous than a zero-porosity fabric... :), but a greater difference is that
> paraglider materials are less elastic (which is why an opening shock from
> terminal would shred them).  

Has anyone actually tested this?   Also I believe that a paraglider would 
need a drogue to open...

> Even standard parachute line cord has too much
> stretch for paragliders (I know someone who injured himself when he rigged
> his 'glider up with standard jacketed suspension line and couldn't control
> it enough to keep from stalling out).

Good Paragliders use kevlar shrouds

> 	These canopies allow a much greater glide ratio than parachutes, and
> allow (good) pilots to stay in the air for hours.  Anyone who's been hanging
> in a harness for over 15 mins. can understand why paragliders grew seats as
> they became larger; multiple line groups are connected to the seat along its
> length so that shifts in weight can steer the paraglider.  

That depends on the harness, most control still comes from the brake lines
attached to the trailing edge.

> To stay flying,
> 'glider pilots catch thermals (and carry variometers to help find them).

Or catch ridge lift on slopes facing into a wind. You need about a 25 kmh
breeze to stay up. Mostly canopies have max speed approx 40kmh

> 'Glider competitions sprang up, and have categories much like glider 
> (sailplane) competitions: net distance, time around a course, etc.
> In summary, you can still buy small (<5 lbs!) 7- or 9- cell
> paragliders to use for descents (and this is standard equipment for climbing
> in Europe), or you can go the competition 'glider route.  They're probably
> more expensive than "normal" 'chutes because (1) they're larger, (2) the
> designs are more complicated (tons o' cells, tons o' lines, and a more
> involved airfoil design), and (3) the market is still relatively small.

I dont know what a parachute costs, but I can get a glider ready to fly 
for around $2500 new, $2000 second hand. 

just my $0.02 worth

KLox