Forums: Skydiving Disciplines: Wing Suit Flying:
Head Up??

 


TB99  (D 26447)

Mar 18, 2003, 5:52 PM
Post #1 of 6 (845 views)
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Head Up?? Can't Post

What do you guys think about keeping your head up instead of your chin tucked for flight?!?? You keep your whole body still dearched with shoulders rolled and everything else the same, legs arms, etc ... but instead, you look up instead of tucking. It's weird at first because you have the tendancey of wanting to change the rest of your body, but it's easy to get used to after only 1 jump.

Reason I tried this was because here in Deland, a fellow birdman jumper was talking to Jari and the technique of putting your head up actually came from his mouth.

Personally, I've done about 4 jumps like this and they were consistantly better for me, my last one I tried the normal way, and it didn't come anywhere near the same results. Although, the only theory I have with that is that I was really focusing on having an awesome body position because it was different and when I went back to the normal method, I wasn't paying as much attention to the rest of my body and was just normal flying. Maybe, maybe not ... I usually try and max flights when I go solo, but it's one way to discredit.

I dunno, I'd like to hear other experiences!!

(The reasoning I was told why it was better was because the airflows under, creating more lift, but I'm visualizing the shape of the airfoil being distorted with the head up ... I don't know!Crazy)


ManBird  (D 28001)

Mar 18, 2003, 6:52 PM
Post #2 of 6 (826 views)
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Re: [TB99] Head Up?? [In reply to] Can't Post

Head up for sure. Keeping a head high attitude will keep you from leaning too far forward, so long as you're moving your head only at the neck and not pushing your chest out/down.

Good examples of the difference are the videos of Robert's jump from Arco in December, and his jump in February. In the December jump, he launched a little head low, with his legs a little too far back, and while he did have some motion almost right away, the initial descent was significantly longer and faster (down) than his moe head-high-legs-a-little-in launch in February. I believe the suits were a bit different, but it probably didn't make a giant difference compared to his body's angle of attack.


Premier TomAiello  (D 22400)
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Mar 19, 2003, 5:42 AM
Post #3 of 6 (789 views)
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Re: [ManBird] Head Up?? [In reply to] Can't Post

I definitely think that a head high flying position has given me better results in glide angle. I just seem to get more forward speed, and slower descent rate, with my chin up.

In reply to:
...initial descent was significantly longer and faster (down) than his more head-high-legs-a-little-in launch...

However, the speed and length of the inital "drop" ought to depend more on the "float" of your body position than it's efficiency for forward flight. The length of the "drop" is not necessarily a good indicator of flight efficiency or technique (not in the specific case--I doubt that anyone aside from Jari approaches Robert's flight efficiency).

I'd guess that the chin up position maximizes both body surface area and bottom skin "cup" and thereby initiates flight slightly faster. But I don't think that's a good indicator of general flight efficiency, nor do I believe it's the dominant factor in initiating flight sooner. For example, I think body angle is more important than head positioning in determining the "drop" interval before flight. As I recall Robert once said that "drop" time was almost entirely a function of wingloading.

Damn, this wingsuit stuff is so much fun. Smile


ManBird  (D 28001)

Mar 19, 2003, 7:09 PM
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Re: [TomAiello] Head Up?? [In reply to] Can't Post

In reply to:
However, the speed and length of the inital "drop" ought to depend more on the "float" of your body position than it's efficiency for forward flight. The length of the "drop" is not necessarily a good indicator of flight efficiency or technique (not in the specific case--I doubt that anyone aside from Jari approaches Robert's flight efficiency).

I'd guess that the chin up position maximizes both body surface area and bottom skin "cup" and thereby initiates flight slightly faster. But I don't think that's a good indicator of general flight efficiency, nor do I believe it's the dominant factor in initiating flight sooner. For example, I think body angle is more important than head positioning in determining the "drop" interval before flight. As I recall Robert once said that "drop" time was almost entirely a function of wingloading.

Right, I don't disagree with anything here, but this wasn't my point. I wasn't speaking on Robert's general flight effeciency in those videos. I was just using the body position during the launches as examples where the differences between head-high and head-low flight are fairly noticeable. Continuing to use those videos as examples, look at the "external" views when he launches to note the position of his camera. Then watch the onboard video of him in full flight. The reason you can see his rig throughout those flights is that his head is up.

On launch position, here's how I look at it: Body position has no effect during the drop. As you approach/reach terminal, you can start flying. Common sense. However, body position during the drop can determine what terminal is going to be and how much control you will have at different altitudes. Steep/head low flight (after the drop) may be 60 - 70 down, while head-high may be 40 down. If you drop in a head low position that would give you 65 down in flight, it's going to take a bit longer (altitude) than assuming a position where your terminal is going to be 40. It takes longer to hit 65 than 40. Therefore, it takes longer in the "65" position to attain the same level of control of the "40" position. Theoretically, you could launch the suit head down, and if you manage to adjust to your optimum body position at the exact moment that you hit your optimum body position's speed, then the it wouldn't make any difference. In all reality and practicality, this isn't the case.

Of course, it all slides... there is no on or off speed. There is a hyperbolic control curve, caused by the increase in viscocity between the jumper and the air. It has more to do with the amount of control you have at different speeds than control on/off at different speeds. You can attain the ability to control your fall at the same altitude, regardless, but a wingsuit will give you more control at lower airspeeds, and a wingsuit sitting in the right position, waiting for its control point, will give you control sooner than that same wingsuit that needs some position tweaking.

In other words, better launches are better. :)

Note to people who aren't Tom: All of the above refers to fixed object jumping only. This doesn't apply to jumping out of a plane that's already traveling 80 - 100 knots, so no comments like "Are you crazy? I can fly right out the door!". (dammit)


ManBird  (D 28001)

Mar 20, 2003, 1:45 AM
Post #5 of 6 (719 views)
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Re: [ManBird] Head Up?? [In reply to] Can't Post

BTW, Tom, the above response isn't really targeted at you. In looking it over I could see that a lot of this could read as condescending or argumentative. Not the case.


TB99  (D 26447)

Mar 20, 2003, 3:04 PM
Post #6 of 6 (687 views)
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Re: [TB99] Head Up?? [In reply to] Can't Post

Okay ... I talked to Jari today to clear up this issue. I hate hearsay, because what my buddy told me was nothing like what Jari said!!

Chin tucked in really good is best for head position he said! If you really want to max out, your chin really tucked in takes out a LOT of drag.

These WERE from Jari, I talked to him personally today when I went in to finish my payment on my GTi (which will be here soon, yay!).

I'm going back to really digging my chin into my chest for those solos I try and max ...



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