Alex362 0 #1 Posted May 18, 2021 So I am looking to buy a Pilot 9 150 for wingsuiting and Aerodyne seems to have to different material combinations, ZPX and ULPV. If anyone has jumped the 2 on the same wingloading and square footage, then did you notice any difference in the performance aspects, especially the flare? Quote Share this post Link to post Share on other sites
Alex362 0 #2 May 19, 2021 Or any information regarding ULPV and performance in general will be appreciated :) Quote Share this post Link to post Share on other sites
sundevil777 93 #3 May 19, 2021 I think that using non-zero porosity fabric on the lower skin does not result in lower performance. When a wing is flying at high angles of attack (such as during a flared landing), it is very important that the airflow over the top of the wing stay "attached"/not separate from the surface of the wing. If air is leaking out through the top skin fabric too much, then I think it has the effect of separating the airflow. Conditions on the bottom skin of the wing are very different, with separation not being an issue, so leakage through non-ZP fabric on the bottom doesn't matter. If it was possible to actually suck air into the wing through/from the top skin, then you get the ability to produce good lift at even higher angles of attack, as the airflow stays attached when it otherwise would not. This has been done on some experimental airplanes, including a Boeing 757 testbed that had part of the wing drilled with very tiny holes and a vacuum applied to suck air into the wing. So, air leaking out through the fabric matters a lot for the top skin, but not for the bottom, as long as it is not so much that cell pressurization suffers. That's my theory on why non zp is being applied on bottom skins, and I think it makes sense. In my previous life I was a mechanical design engineer, even did such for the Boeing company. Quote Share this post Link to post Share on other sites
BMAC615 205 #4 May 27, 2021 I know you didn’t ask this, but, I highly recommend you reconsider using a 9-cell for wingsuit jumps. They are fine when everything goes right and not fine when everything goes wrong. If you’re going to buy a new canopy, might as well get the right tool for the job. 1 Quote Share this post Link to post Share on other sites
