skydivah1 0 #1 February 26, 2014 Got my velo back today with thinner hma 500s on her and got to thinking: Does less wind resistance mean that you gain extra distance (how ever miniscule that may be) but AT THE SAME SPEED? In other words, you're carried further - not because of extra speed - but because you have less hindrance in parasitic drag which keeps you swooping across the ground further? The initial "gate speed" is the same but you will have gained more ground before it begins to die off? OR You gain more distance because you have extra speed due to less wind resistance?? Or A combination of both? Somebody sort me out here... Quote Share this post Link to post Share on other sites
Pobrause 6 #2 February 26, 2014 Of course both. E.g. you fall faster in freefall when you reduce the surface exposed to the wind. Same applies under canopy when building up speed. The less surface you expose the faster you go. Less drag on a given speed means you can hold that speed for a longer period of time, gliding more efficiently through the airflow --> swooping further. but there must be some aerodynamics engineers around that could give better and deeper insights to this.------------------------------------------------------- To absent friends Quote Share this post Link to post Share on other sites
Polorutz 0 #3 February 27, 2014 I'm not a swooper but I'm a pilot with a physics background. In sport skydiving the only thing producing lift is your parachute, unlike in airplanes where the fuselage can come into play. Therefore, when you reduce drag in the system as a whole, you aren't really changing the amount of lift the aerofoil is producing, what you are doing is removing drag for that aerofoil to fight against. When you're in full flight, except in phases of acceleration, the aerodynamic forces on your system are in balance, if you were to accelerate, the parasite drag would increase with speed, which would eventually lead the system back to its original balanced speed. Imagine you instantly change the lines in flight, now your system is no longer in balance because you have less drag, what happens then is that the system accelerates until the point where the speed itself causes enough drag to stop the acceleration. It's useful to know that there are 2 types of drag, profile drag and parasite drag. Profile drag is the one you're thinking about when changing lines, presenting less surface to the airflow, etc... Parasite drag is proportional to the airspeed, the faster you go, the more drag you will create. Think of it as dragging your hand through water in a pool, the faster you move your hand, the more force you'll feel push against it. EDIT: To answer your question, reducing profile drag by changing your lines means both a higher airspeed for full flight as well as a reduction in drag overall. What this means is that most definitely your gate speed will be higher, and due to the drag being lowered a bit, the rate at which that speed bleeds off during the swoop is lessened to a degree, so you'll fly farther too. Quote Share this post Link to post Share on other sites
morris 0 #4 March 1, 2014 Two types of drag? How about induced drag, number three. And linedrag is a parasite drag, not part of Profile drag... Quote Share this post Link to post Share on other sites
Polorutz 0 #5 March 1, 2014 I was trying to explain the situation in a concise manner. Profile drag is part of parasite drag, I just wanted to differentiate between drag that increases with airspeed (all parasite drag) and just form drag. It's been a while since I've reviewed these concepts so might have gotten the terms wrong but the logic still works. Quote Share this post Link to post Share on other sites
