KrisFlyZ

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Posts posted by KrisFlyZ

  3. Quote

    I blitzed my personal best on my old GTi according to my Protrack - shows how the technology has moved on if nothing else.



    If the suit had the exact same area as a GTi then 'new technology' might be the reason. When you got a suit with nearly double the area, a comparison is pointless.

    Kris.

  10. For Ground Effect to be a siginificant factor, the distance between the ground and the wing must be really small in wing span terms.

    Span dominated ground effect reduces induced drag (by not allowing the wingtip vortices to form). for a 50% reduction of induced drag the wing must be 10% of the span from the ground. About 6 inches for a 5 foot span.

    Chord dominated ground effect may increase lift but the wing must be pretty close to the ground. As an example. A height of 5% of chord for a 30% increase in lift. That is 3 inches for a 5 foot chord.

    The road will need to be at the exact varying glide angle as this persons flight characteristics in a flare under the atmospheric conditions.

    In other words, it ain't happening :P.

    Kris.

  15. Quote

    Having a suit with a little extra room for clothing (or growth:$:P) is not a bad thing..

    Though it may affect your L/D by 0.00032698 ofcourse..




    No no it effects it by 0.00032699. :P

    I can prove it.

    Kris.

  16. Just saying Full flight is confusing. Other things being equal, the opening speed depends on the speed of the air that the PC is released into. So spreading all wings but flying slow will result in a slower opening compared to doing the same thing but flying faster.

    I have some interesting video on full flight deployments. Will upload once I get home.

    Both deployments are from full flight but the first flight is flown much steeper.

    Video 1(v2Ex4St.mov) is a flight with a steep pitch(angle). The resulting opening is brutally fast.

    Video 2(v2Ex4Fl.mov) is a flight with a slightly shallower pitch angle. Nice and gentle opening.

    Kris.

  17. Glad that you are experimenting Tony :)
    Attaching the wing like the 'Mercury Wing' is causing the leg wing to be at a reduced angle of attack compared to most prior designs. The Phantom and the Rigor Mortis have the leg wing attached half way between the toes and the heel.

    Gliders at a reduced angle of attack fly faster. Do they glide better? That answer is not simple. Only testing will tell.

    I would love to fly a suit that has this Mercury leg wing and smaller armwings(with smooth leading edges, please) that are also attached in the same manner. Speed baby...speed.

    Kris.

  19. Quote

    You basicaly answer this question yourself saying:

    Quote

    while I perceive an increase in speed, my arm-wings start fluttering



    The wind normaly detaches from the wings a short distance behind the leading edge already. Choosing a steaper angle means the wind starts to attach to the wing. Causing it the flutter and flap, as the wind starts to grab/attach itself to more of the wing on top

    You may not have a clean profile/body position, which means the wind never reaches a clean airflow. And keeps the flutter going. But seeing your performance is increasing, you're definately not doing something wrong. You just have to find out how to do it better..


    Don't agree with some bits of what you said Jarno. :P

    IMO, Attaching air does not cause flap or flutter. At low angles and fast flight regimes, the fabric is pulled parallel to the body. This will not cause or keep flutter going on a properly inflated wing.

    Proper inflation makes the wing rigid and flap proof. The key reason for flap is improper inflation. In this case, my best guess is that the suit has been taken past its design boundaries.

    Every inlet based on the design works effectively in a angle of attack range. Here are a few thoughts on inlet types the angle of attack regimes that they are most efficent at.



    Quote



    Inlet types and inflation
    =================

    The amount of air entering the inlet is dependent on the size of the inlet, speed with which it is moving through the air and also on the angle the inlet makes with the air.

    a) Mesh covered hole in the wing.

    The area of the inlet is parallel to the surface of the wing. This is most effective at higher angle of attack.


    Why? Imagine trying to block flow of water along a stream with a flat plate. How will you place the plate in the stream? At 90 degrees to the flow. At any other angle, the plate is less effective. The inlets(Type a) on wingsuits are the same way. The lesser the angle of attack, the less effective they are. The S-fly inlets also fall under this category.

    b) Scoops

    Like Phantom and Tony suits or like the front air deflectors on the Skyflyer series of suits.

    Even though they look different and are placed at a different part of the wing, they work similar to the mesh covered hole inlets. Because most of the the opening area is parallel to the bottom surface of the wing.

    I cannot talk about Tony suits from experience. It is possible to fly a phantom so steep that the armwings will start to loose inflation.

    c) Scoops facing the correct direction

    V2 inlets

    These inlets have the inlet area facing 90 degrees to the direction of flow at low angles of attack and are most effective in the low angle of attack regime.

    That is what Robi designed them for.



    Kris.

  20. Quote

    -The angle I'm flying is too steep and therefore the wings lose pressurization due to the air not hitting the arm inlets at the correct angle. I'm skeptical of this due to the airlocks which, at least with the leg wing, seem to keep the wings rock-solid.



    I agree with this theory.

    The leg wing inlet usually (unless you are flying completely flat...When we roll the shoulders, we are reducing the angle of attack of the arm wings and top section of our body and thus reducing drag) is at a higher angle of attack than the arm wings and that may(depending on inlet type) make the leg wing inlets more effective than the arm wing inlets when flying steep.

    This is why I asked the question in the Apache thread if anyone has flown the Apache steep...really steep. The same thing you describe can be done on a Phantom.

    Just ease off on the steepness and see what happens(Obvious really).

    Airlocks will not help when there isn't enough pressure(or dynamic pressure) to force the air into the wings.

    A properly inflated arm wing does not need to be tensioned outwards, only forwards(form the leading edge ).

    Kris.

  21. Quote



    From my experience about the GR and speed I may say following:

    There are a few well known rocks in Europe for which we know exactly how good you need to fly to get down safely.

    A few require 2.1:1 and some even harder at 2.3:1. The funny thing is that only a handful of people so far have jumped them successfully.



    Why only few people are doing it is an interesting question. My answer is that it is Robi and VKB's fault ;).
    Most people these days want to do one jump flying away from the wall and start swooping it on the second jump.

    Seriously...

    This year several jumpers in tracking gear were flying back high over the landing area from #6. High enough to pull over the lighthouse if they kept going. The Flying Finn as everyone called him was easily pulling over the lighthouse.

    Pete the Aussie with less than 10 big wall BASE jumps was pulling pretty high over the landing area using tracking gear. None of these guys are thin and tall, neither are they using special thin rigs for tracking. They are average height and solidly built.

    2.3 or 2.4 is not hard to fly just because only a few people have done it so far. Afterall, It has been done in a medium sized suit(Phantom) and with a big fat rig as well. For 50 second flights, endurance is not an issue for the phantom.

    My view is that anyone that is of reasonable build can do it in the correct sized suit if they really want to in one season of jumping. The reason why only a few people are flying 2.3+ must be something else.

    Quote

    In overall; writing that glide is 3:1 or that Speed on Phantom is 160 for GR jump is not correct – flying Wingsuit is not this straight forward!



    Considering the source of the 2100m flight from Smellveggan in no wind, you are responsible for the 3:1 :P. A 2100m flight from Smellveggan in no wind is over 3:1 L/D whichever way you cut it. Are you saying that it never happened?

    No one said 160km/h is the speed of Phantom for best glide. 108-116 mph(total speed along the vector) was the range of speeds observed by me on my normal Phantom jumps. That information was provided because Boris asked for it multiple times, it has no other relevance to this conversation. Simple. :)
    What is your typical L/D in a Phantom? Because it is a reasonable assumption to make that Boris was flying better than you on that jump or atleast as good as you for you not to have caught up with him assuming it was a fair race to begin with.

    Kris.

  23. Quote


    So performance numbers from GPS flights can't be taken strictly serious. Not because the GPS is imprecise, but that the numbers do not reflect the affect of the wind.



    GPS numbers with whatever correction we can apply for wind are helpful if you can download after the jump and compare with other jumps on the same day.

    For me the numbers out of the airplane matched quite well with numbers from Smellveggan jumps. I discarded the ITW data because opening altitudes were too high for GPS based altitude to be trusted(too much possible error).

    I don't carry a GPS anymore on my jumps, its gotten too boring.

    Kris.

  24. The way L/Ds have been reported on this forum(horizontal distance / vertical - 300(150 for opening and deployment).

    A flight of 2100m for 930m of altitude is an L/D of 3.33(2100/630). See why 1.8 sounds too low?

    From an airplane there is no altitude used in starting a flight. So the numbers from an airplane will be better if you use the method you used to calculate L/D.

    Kris.
    P.S: As a side note, I must say that the flight in Kjerag_07.wmv is nowhere near 2100m(you maybe talking about another flight). The 2km point(the ladder in the wire fence behind the white house...This is same fence the we climb over to access the pendulator area) is to the left and ahead of the opening frame and it is not hard to tell that the camera is mounted pointing forwards, this puts the flier behind where the opening point seems to be from the video.

    As an example , if you stop the video at 1:15 the shore closest to the wall, in front of the Big rocks is 1500m compared to 1600m for the point of the nose on the other side of the river. The white house is 1900m away and the closer you come towards the wall(perpendicular to it) from the white house the distance to the exit point decreases.

    I walked the landing area several times with a GPS(Hey Scott...this boosted my ego so much, I had a Hard On the entire time:P:ph34r::D).

  25. Quote


    Obviously you don't understand what I want to say.

    I am not saying that I am actually flying 1.8 nor that my total speed is 80 mph. Probably it is better than that..




    Let's break down the problem. The total flight time is ~92 secs(1600m vertical distance and 39 mph average speed).

    a) Exit(at Point A) facing North(for the sake of clarity) at 65 knots(33.22 m/s).
    b) Turn south quickly(less than 2 secs)...maximum distance traveled in the North direction is 66.44m.

    c) Maximum of 10 secs is needed to cover this distance going south. A lot more than 66 m can be covered in 10 secs from a still air exit.

    Using values for this, show me how the speed on the south leg could have been 96 mph (total speed along glidepath...or a reasonable number).

    96 mph is too slow. If you jump with a GPS for a few jumps and see what speeds you get when flying for distance, you will see why these numbers you post are wrong.

    I am almost the same height(187 cm) and was the same exit weight as you when I got this GPS data(last year).

    Downward speed was mid 40s and GR was between 2.2 and 2.4. That makes the total speed range 108 - 117 mph.

    Kris.