Sirob

Members
 View Profile  See their activity

  • Content

    70

  • Joined

  • Last visited

  • Feedback

    0%

Posts posted by Sirob

  7. I noticed improvements while playing AVCHD with latest update of Sony Picture Motion Browser version 4.2.10

    It is also stated in release note for it:
    Quote

    Support for DXVA 2.0
    DXVA (DirectX Video Accelerator) 2.0 considerably enhances the playback performance of AVCHD contents.

  11. Quote

    There are two areas in wingsuit flight that laminar flow is ALMOST acheived.
    I capitalized ALMOST for one.




    Almost achieving “laminar airflow over wingsuit” reminds me of a joke when some guy was bragging that he “makes love almost every day!”

    He said: “I made love almost on Monday, almost on Tuesday, almost on Wednesday,…”

    Airfoils that are closest to achieving laminar airflow are used on the wings of open class gliders (costing number of hundreds of thousands $ or EUR).
    Compare them with the airfoil on the wingsuit.
    I think that it requires very extensive imagination to see any similarity between the wing and airfoil on the wingsuit and the wing and airfoils on open class glider.
    Laminar flow on non rigid wing is illusion.

    Boris

  12. Landing speed was just indication in comparison to speed we have with wing suit.
    I would say that Mustang wing was quasi-laminar wing, maybe first real attempt to have laminar flow.

    In short - very different animal than our wing suit wings.

    Boris

  14. Quote

    Do you have data for lift and drag as functions of angle of attack?
    And if yes, can you share it?



    No, I don't have data for lift and drag as functions of angle of attack but I have data for pracitcal usefulness as a function of narrow angle of view.

  15. Quote

    James, Robi, and Boris, (others?) do you have any video of similar experiments to see what happens with airflow over the wings on a wingsuit?



    Of course Phoenix-fly and Atair have it for wing suits and for canopies.
    Any serious development will try to collect as many data as possible.

    Boris

  16. Looks like basic are ignored (again and again)... [:/][:/][:/]
    I suggest to all of you with doubts to read WS flying and Basics of Aerodynamics 1 and 2 here http://www.phoenix-fly.com/articles.htm.

    Concerning videos of wing suit airflow, have you seen how airflow looks on our skydiving canopies?
    I think many of you will be surprised - I was...

    To all of you with doubts - "Is there any lift in wing suit flying?" or "Wing suiting is really nothing more than an assisted track", few questions:
    V2 is at least 30% - 35% faster than Stealth and have less wing area but it have about the same (or better) glide ratio, why?
    Good tracker is flying 1:1 or better, wing suit have way better than that. Why is wing suit better if it is just "assisted track"?

    To all that are still having problem with terms "laminar", please read this article (again and again):
    http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=2683420;#2683420

    Many of skydivers are trapped with time and vertical speed as the only relevant factors in WS flying.
    In one of my previous posts, one of the posters wrote me: "The way I read it, though, leads me to believe that you guys think that all we here in the states care about is vertical speed.".
    Looks like it is becoming more and more true... If it is so, Para Foli's or Manta's will be the best skydiving canopy....

    Boris

  17. I started with 106 jumps filming 4-way team in order to be ready for international competition (that happened 50 jumps later). I knew that I will do the same (filming the same 4-way) in next years and that was the only option for the team and me. Motivation and dedication was on the high level and there was constant pressure every single jump for improvement (no video bust on exit, all grips in the frame, flying on the close distance, etc...). It was hard work but it pays off very quickly and my skill was good enough to compete without any problem for me or the team.

    As stated here many times before, important is what you are doing, who is with you and, for me the most important factor, your motivation and dedication. Numbers are just numbers ...

  18. You forgot competitions (individual performance - time, distance, speed).
    There were several nice competition, each on his own set of rules in search for the best form of "how to do it".
    GPS devices prove themselves not to be trusted and dueling seems to be very interesting form.
    What artistic WS competition will bring, we will have to wait and see....
    Good luck for all future competitions!!!

  19. For example take Robert's jump from Smellvegen.
    Here is just straight flight from point to point.
    Used height is 930 meters, covered distance is 2100 meters and total time is 50 second. Wind was close to zero as I recall.
    Simple calculation will give you GR 1:2.25 and average total speed 165 km/h (102 mph) - (average speed is total path over total time).
    Robert is flying V2 and I trust to him that Vampire is still faster than Phantom.

    Regarding use of GPS, in my opinion people are trusting too much to the GPS numbers.
    I am not convinced about precision and accuracy of GPS data.
    Is there any test of precision and accuracy of GPS device in skydiving environment?

    I believe more to the detailed map and stopwatch even if that makes my GR lower than what people are measuring with GPS's.
    I will end further discussion here.

    Regards,

    Boris

  22. Kris,

    Jump was distance chasing, not speed chasing.
    Robert was not slower - we were equally fast (if you ask me). :P
    On max glide speed is not the fastest we can fly.
    In my opinion your calculation (96 mph) fits here quite well.
    I am using my calculation model for distance only. How it works for speed I don't know.

    What do you think, what total speed you (should) have while flying max glide in Phantom?

    Boris

  23. Quote

    Exit in opposite direction to flight path does not do anything, if, you did a fast turn.



    Really?!
    You have to kill the speed you get from the plane (cca. 65 kt), turn 180 degrees and fly back.
    Flying in the same direction as the plane does not help my GR, turning 180 degrees also does not help my GR.
    By looking to my exit point (relative to the ground) I spent some time of my flight without flying single meter back.

    I think it have some impact on my performance...the way how I am measuring it.

  24. Quote

    1.8 is too low an estimate.



    The way I am looking to Glide Ratio - I don't think so.
    Remember, this is average of the whole jump - from the exit in opposite direction to the flight path till opening with assistance of 0 km/h wind.

    I am not talking about GR during the best part of the flight, like Robi explained here - http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=2731517;#2731517.

    If you do some very rough calculation, assuming your average vertical speed to 65 km/h, 1 m/s of down wind is adding about 0.05 to your glide ratio. (With help of the 4 m/s wind you are flying over 2.0 GR.)

    Data calculated that way pretty good match with the jumps I am making here with the estimated wind speed at the altitude (from meteo or pilot information) and jumping over known land marks around airfield (as I described in previous threads).

    Boris