mattlong 0 #1 April 4, 2008 I've read the PD document about wing loading http://www.performancedesigns.com/docs/wingload.pdf, and was interested by the paragraph that states "Wing Loading is the biggest determinent of speed". If this is the case, can you estimate your airspeed based on your wingloading? Cheers Matt Quote Share this post Link to post Share on other sites
parachutist 2 #2 April 4, 2008 Not very accurately. The only certainty is: the higher your wing loading under a model x canopy, then the higher your air speed will be under that model. You can guess within the general ball park range though, such as .8 wing loading is likely 7-10 mph, 1.0 probably 8-12 mph, 1.2 = 10-15 mph There are too many varibales to predict air speed accurately. Some of those variables: - different models of canopy (different airfoils, different aspect ratios, etc) - altitude (canopies fly faster at higher altitudes than lower) - air temp (faster through hot air than cold) Quote Share this post Link to post Share on other sites
billvon 2,990 #3 April 4, 2008 >There are too many varibales to predict air speed accurately. >Some of those variables: >- different models of canopy (different airfoils, different aspect ratios, etc) Agreed. >- altitude (canopies fly faster at higher altitudes than lower) Actually, the _airspeed_ will be the same on your canopy no matter what the elevation you jump at. >- air temp (faster through hot air than cold) Same. Airspeed won't change (although your groundspeed certainly will.) Quote Share this post Link to post Share on other sites
JohanW 0 #4 April 4, 2008 Bill, I think you're talking about some other kind of airspeed than the one a layman would think of first. There's indicated airspeed and the other one which I can't remember right now, and I'm not the correct person to explain anyway. But could some pilot, or anyone else that knows what airspeeds I'm talking about, and does know the difference, please explain? I think it's pertinent to the discussion. And it's rather counterintuitive (to me at least).Johan. I am. I think. Quote Share this post Link to post Share on other sites
DrewEckhardt 0 #5 April 5, 2008 QuoteBill, I think you're talking about some other kind of airspeed than the one a layman would think of first. There's indicated airspeed and the other one which I can't remember right now, and I'm not the correct person to explain anyway. But could some pilot, or anyone else that knows what airspeeds I'm talking about, and does know the difference, please explain? I think it's pertinent to the discussion. And it's rather counterintuitive (to me at least). Indicated airspeed (total pressure of the air molecules hitting the measuring device) is unchanged regardless of density altitude. True airspeed (velocity vector magnitude relative to the air mass) is higher when air density is lower and there are fewer molecules running into the airspeed indicator. Since your reaction time requirements and kinetic energy on landing are a function of your velocity vector plus the wind's, true airspeed is more relevant for skyiving. Quote Share this post Link to post Share on other sites
d123 1 #6 April 5, 2008 The main question of the non powered flight era is: How does a wing with a suspended weight underneath it finds the right balance between AoI, AoA(CL) and air speed? From Lift only point of view we could use these formula's to approximate the speed increase as we increase the WL. http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=3155098;#3155098 Two things might be worth mentioning: - as you increase WL via reducing wing surface (downsize) the air trajectory (L/D) will only get worse and your wing will fly at a higher angle of attack. -> easier to stall! - as you increase the WL via weight bearing the L/D, AoA & AoI might remain the same .. (not sure about it but I can't prove the opposite) so the formula for speed V2 = V1 * sqrt (WL2/WL1) might be correct. take it with a grain of salt ... or weed ... ... yeah I know ... yawn ....Lock, Dock and Two Smoking Barrelrolls! Quote Share this post Link to post Share on other sites
Rdutch 0 #7 April 5, 2008 QuoteI've read the PD document about wing loading http://www.performancedesigns.com/docs/wingload.pdf, and was interested by the paragraph that states "Wing Loading is the biggest determinent of speed". If this is the case, can you estimate your airspeed based on your wingloading? Cheers Matt Definitely, you can predict airspeed!!! My prediction Airspeed will dominate the world meet this year! Oh your probably talking about something else. Ray Small and fast what every girl dreams of! Quote Share this post Link to post Share on other sites
