# Why triple parachute works?

by jostpuur
Tags: parachute, triple
PF Gold
P: 3,103
 Quote by jostpuur Bernoulli principle only applies to noncompressible fluids, so you can forget it when dealing with gases.
Not true. Bernoulli's law was developed from the study of uncompressibles, but it also applies to gases under certain circumstances, for instance when the flow rate is slow compared to the speed of sound as it is in the topic of this thread.
 Sci Advisor Thanks PF Gold P: 12,267 Jotspur "I would try to understand airplane wings from the point of view that the wings will shoot air downwards when they move forward. So the lift follows as result of Newton's laws. " I don't think the simplistic argument based on Momentum change is sufficient to explain the force generated by an Aerofoil or, as an extension, to the fact that a yacht sail provides windward 'lift'. I know you can fly an aeroplane upside down by using the momentum change of the air but that is a very inefficient mode of flying and 'planes are designed much better than that when they need to be efficient. Also, how else is drag to be explained? Your simplified argument would imply that vehicles should be pointed at the front and the back end shape would make no difference at all - ideas which were tried long ago and found not to work.
 P: 8 With water rockets as one of my hobbies, I can sure relate to just one parachute tangling in ways that do not seem possible. I have never attempted using more than one but understand for larger parachutes using a drogue parachute is a good idea. Bill Kuhl
P: 15,319
 Quote by ScienceGuyOrg but understand for larger parachutes using a drogue parachute is a good idea.
Are you sure that isn't a drouge parachute?

( Running gag)
P: 4,777
 Quote by ScienceGuyOrg With water rockets as one of my hobbies, I can sure relate to just one parachute tangling in ways that do not seem possible. I have never attempted using more than one but understand for larger parachutes using a drogue parachute is a good idea. Bill Kuhl
I knew your name looked familiar, you fly at FSA. Your picture is on the January newsletter.
Thanks
PF Gold
P: 12,267
 Quote by DaveC426913 Are you sure that isn't a drouge parachute? ( Running gag)
How are running and drougeing connected? Are they both methods of flight?
P: 15,319
 Quote by sophiecentaur How are running and drougeing connected? Are they both methods of flight?
http://physicsforums.com/showpost.ph...8&postcount=16

http://physicsforums.com/showpost.ph...90&postcount=2
http://physicsforums.com/showpost.ph...86&postcount=1
etc. etc.

Doing a PF search for 'rouge' will turn up dozens of posts...

And finally:
http://physicsforums.com/showpost.ph...&postcount=112