yuri_base

Hmm... a male stripper in the NPS uniform with handcuffs. Even PRICELESSER! Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Do you see in the video why the PC stayed on her back during the barrel roll? Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Let's thank Abbie with a stripper!!!!!

I think we're not done with learning lessons from this accident yet. We can't attribute the whole jump to the Freak One-Time Glitch. She was very quick in realizing the Glitch and started fighting it almost instantly. But the fight was unsuccessful. From 3.25s to ~5.5s, for the whole 2+ seconds in the 70 to 90mph wind, the PC failed to do its job. Why? An in-depth analysis of the video from 3s to impact will answer this question. But even before that, we can see that the technique of turning on your side to clear the burble gives the Freak One-Time Glitch another chance to kill us. It places your arm right in the way of the PC, creating a chance of entanglement. If you overrotated on your back, the canopy extraction can be delayed, too, due to distribution of the pull force. And if you overrotated even further, the canopy-bridle entanglement can happen. Maybe we can rethink this technique borrowed from skydiving and develop the one that doesn't give FOTG another chance and works faster? How about bending forward while simultaneously bringing legs forward as if you're trying to touch your knees with your head. This will clear the burble and keeps the path for PC clean. You can also reach BOC with your wrist to dislodge the PC but your arm will not be in its way. Thoughts? Yuri Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Guys, Just ask Medusa how to fly inflated Vampire on your back. No back vents needed! You may need to point your toes backwards to put your booties on, though! Yuri Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Tony, I used to do research on behavior of high-temperature superconductors in strong microwave field. I can help you with your questions. I just need a couple of numbers to plug into Maxwell equations. So, what's her phone number? Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

When using Century Optics 0.55x with HC-1, I see this strange effect: the picture becomes kind of "liquid", not moving as a whole, but rather the center is kind of "floating" relative to corners. I think this side effect is created by electronic image stabilizer. Wide angle lens introduces significant barrel distortion, which has different strength at the center and corners. When electronic IS moves the cropping frame around to compensate for the shake, the center of distortion appears to be moving and that makes the image look "liquid". Do you know which WA lenses have the least barrel distortion (while maintaining the high resolution suitable for HDV)? Thanks! Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

What shutter speed do you use to achieve F < 4.0? What are the disadvantages of setting the shutter speed even higher than that? Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

At 3.25s, she was falling at 65mph and according to the report above, by that time she cleared the burble by turning on her side. At 65mph, it would take ~0.1s for PC to pop the pins and another ~0.2-0.3s to linestretch. According to some witnesses, the pins poped just before the impact at 5.8s. What was the PC doing from 3.25s to ~5.5s in clear airstream accelerating from 65mph to 90mph, if it wasn't entangled with her body? Anyone have a different video of the accident showing what happened after 3s? Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

You'll be even hotter if you wear a pink ProTec and pink 'Lolita' goggles. Yuri Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

I don't compete. I just love the feeling of ripping through the air and hauling ass across the ground.

That's what I'm saying. It's not the loss of the GPS signal strength (otherwise both horizontal and vertical speeds would be noisy), it's Vista C's freakin' barometer which is totally useless for skydiving. Do you know the way to turn it off and use GPS altitude only? BTW, I kept my head in fixed position specifically to get better data. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Why is the horizontal speed data smooth, then? Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Did one jump with leg wing on Phantom (arm wings collapsed). Tracked in the direction of jump run first with a slow turn for the first 40s, then turned 90 and tracked for about 15s in the direction approximately perpendicular to the wind. Then sharp turn towards DZ and flew both wings for another 40s. Maximum ground speed achieved on perpendicular to wind leg was about 135mph, with glide ratio approx. 1.4. Vertical speed data is so noisy it's not even funny. Vista C was mounted on the side of the helmet. I guess, increased total speed creates even larger fluctuations in dynamic pressure than when flying both wings. Total speed (~160mph) builds up incredible pressure on leg wing, it's almost impossible to keep the wing wide open and I thought it's going to explode any second!!! Arm wings are bitch to keep collapsed, too. After the jump I felt as exhausted as after 20 WS jumps. What can I say... It's a fuckin' Rocket!!!

I thought (and am most likely wrong) that from the deck the perrine had a 5.2s to impact. clarification anyone? Without air resistance, t = sqrt(2*h/g) = sqrt(2*486/32) = 5.5s. With air, you are at 366ft at 5s and 504ft at 6s, so 5.8s for 486ft is just about right. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Just watched "Lemmings Extremes" again, a collection of the Bridge Day's "The Best of the Worst" jumps. Watch 27:45 (or 12:15 on Johnny Utah's "Bridge Day Safety Video"). A guy makes a 2s delay, pitches the PC in a smooth and swift motion and brings his hands to shoulders waiting for the risers. What can be clearly seen is that the PC quickly moves from his right side into his burble and stays "glued" to his butt. There's no bridle to be seen. Apparently, most of the bridle stayed in the BOC. The PC is not inflated as there's no tension in the bridle. At 4s into the jump the guy realizes something is wrong. He looks back and reaches back with his hand, pulling the PC out of the burble. At 5s into the jump, you can see the container opening. At 6s, his canopy is half inflated. At Perrine (5.8s to impact), he would have died. Only additional height of NRGB saved him. His pitch was not weak. Yet, for unknown reason, the PC didn't move further to the side in a tight bundle before inflating, instead, it spread out instantly into a pancake which got sucked into the burble. Thoughts? Any particular method of PC packing that can cause this? It seems, the bridle didn't stay trapped inside the mushroom, it got "dumped" in BOC on pull. Maybe, "Dead Jaap Pack" is not that bad afterall (if the ZP material is not thick/sticky), since it prevents the "bridle dump"? There's not much time at Perrine to clear PC hesitations, and they do happen... Yuri Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

The result is actually quite generic, it is based only on these two assumptions: 1. Gravity is the only engine. 2. Aerodynamic force is proportional to the square of speed (which is true for high Reynolds numbers typical for wingsuit flight). It's just simple physics: the gravitational "thrust" is equal to weight W times the sine of glide angle A. When the glide ratio is high, the thrust T = W*sin(A) is too low to achieve high horizontal speed. On the other hand, when the glide ratio is low, the thrust is high, but the horizontal component of your speed Vx = V*cos(A) is low. The maximum speed is somewhere in the middle. This golden middle happens to be at sqrt(2) = 1.4. It doesn't have to be precisely 1.4. The range 1.2-1.6, as can be seen from the graph, is almost "flat" in terms of horizontal speed. The crucial task is to achieve minimum drag while maintaining this 1.2-1.6 glide ratio. 1.2 can easily be achieved even with the Prodigy leg wing, but to maximize speed, a smoother and tighter pants and low profile rig will help. I'll measure the glide and speed on Phantom leg wing this weekend. Yuri Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Here's the article in case the link goes dead: Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

That's BS!! Everyone knows that number must be PHI (1.618) . Here we go: In equilibrium flight (straight flight at constant speed), the vector sum of lift L and drag D is equal to weight W, therefore, W = sqrt(L^2 + D^2) If d is the density of the air, S is the surface area of the wing, V is the speed, the lift can be expressed as L = 1/2*Cl*d*S*V^2 where Cl is the lift coefficient. Drag is D = 1/2*Cd*d*S*V^2 where Cd is the drag coefficient. Thus, W = 1/2*d*S*V^2*sqrt(Cl^2 + Cd^2) Total speed V is the vector sum of horizontal and vertical components Vx and Vy: V^2 = Vx^2 + Vy^2 So, W = 1/2*d*S*(Vx^2 + Vy^2)*sqrt(Cl^2 + Cd^2) The glide ratio G is the ratio of the Lift/Drag, or horizontal/vertical speed: G = L/D = Vx/Vy = Cl/Cd From this we have Cl = G*Cd Vy = Vx/G and W = 1/2*Cd*d*S*Vx^2/G^2*(G^2+1)^(3/2) The horizontal speed is Vx = sqrt(2*W/S/d/Cd*G^2*(G^2+1)^(-3/2)) For given weight W, air density d, wing surface area S, and drag coefficient Cd, the maximum horizontal speed will occur at maximum of this function: F(G) = G^2*(G^2+1)^(-3/2) The derivative F'(G) must be zero at maximum: dF/dG = 2*G**(G^2+1)^(-3/2) - 3/2*G^2*(G^2+1)^(-5/2) = 0 From here we find that G^2 = 2 G = sqrt(2) = 1.414 Fmax = 0.385 Vxmax = 0.88*sqrt(W/S/d/Cd) So, for given drag coefficient Cd, the maximum horizontal speed is achieved at the glide ratio of square root of 2, or 1.414 - not the Da Vinci "code" Phi. E.g. for exit weight 200lbs (W = 90kg*9.8m/s^2 = 882N), d = 1.25kg/m^3, S = 0.8m^2, Vx = 42m/s*sqrt(G^2*(G^2+1)^(-3/2)/Cd) = 94mph*sqrt(G^2*(G^2+1)^(-3/2)/Cd) The 2-D graph of this function Vx(G, Cd) is in the attachment, and you can see that given Cd, the maximum horizontal speed is achieved at G = sqrt(2) = 1.414. To summarize, to achieve the maximum horizontal speed, glide at ratio 1.4 (angle to horizon 35 degrees) with as little drag as possible (that is, gliding with your body parallel to the relative wind, arms not wide spread, smooth & tight suit). You can achieve this with the leg wing alone or with the leg wing and small arm wings. Yuri Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

A guy makes his first jump (PCA), doesn't unstow the brakes, pulls on front riser loops when everybody on the bridge is yelling, "Pop the toggles!!! Pop the toggles!!!", shlares the tarp with front seat belts and lands on the Bitch without a scratch. I think it's a damn good indicator. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Yes, I got an interesting result: To achieve maximum possible horizontal speed, one should fly at glide ratio of square root of 2 (1.41) with minimum possible drag coefficient. This theoretical result points to leg wing as optimal for achieving max speed, since it's glide ratio lies between regular tracking (~1) and wingsuit (2-2.5). I don't have time now to elaborate, c-ya! Yuri Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Yo! C-ya on Thursday morning!!!

I think we're all right here, we just need to put the pieces together. You do get higher horizontal speed when you plane out from head down (or very steep dive). When you dive at constant speed, the total force the air exerts on your body is vertical and equal to your weight. The components of this force perpendicular and parallel to your trajectory are called lift and drag (there are no two actual separate forces). When you plane out you change the angle of attack and other aerodynamic properties of your body in such a way that the total force the air exerts on your body increases and is inclined forward, accelerating your body horizontally. However, if you plane out as typically done with wingsuit - i.e. you try to level off as much as possible - your horizontal speed will quickly bleed and you go back to your regular forward speed. You need to maintain the high speed over the period of 90 seconds somehow. I believe the best distance in fixed period of time can be achieved not with wingsuit, but with leg wing, because it gives you so much thrust. I recorded sustained horizontal speed of 140mph in Prodigy pants without even trying to max it. Diving with Twin Otter in Phantom, I found that flying just the leg wing allows me to hold the race for longer time. 140mph in 90s gives you 3.5 miles. In 60mph tailwind you'll get 5 miles. Larger (but not too large) wing with smooth & tight legs will give even higher horizontal speed. To achieve maximum sustained horizontal speed, think thrust, not lift. Leg wing is the way to go. Yuri Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Since the jumps were made from a moving object, they don't qualify as BASE jumps. They should be logged as skydives. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

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