yuri_base

Ancient? This modern one seems to be leaping from the big walls. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Yes, the data from the G3 flight shows (acceleration corrected) L/D = 1.6, with potential for 1.8 according to windtunnel data with a different pitch angle. It would be interesting to see the windtunnel data for Vampire or S-3 for comparison. Lokky_luke? Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

I think body & rig dumpen the performance of the wings to a great extent (for example, you made wings with new profile and expect 30% greater L/D... but body with its L/D ~ 1 dumpens the increase to a mere 10%), so the most performance gain will result from eliminating the drag from body as much as possible by putting the body ("fuselage") inline with the flow, just like in any airplane/bird. I don't believe squirrel-like suits (Sugarglider, etc) with huge wings have better performance than airplane-like suits (Vampire, S-3). If they were, we would have seen the real data already. Pony? what pony? Looks like I missed all the fun. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Patent Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Yo! Today I made a few test flights with the Eagle Tree Systems flight data recorder. The recorder has built-in pressure sensors to measure airspeed and altitude, and an option to connect various other sensors, including accelerometer, custom sensors, GPS, etc. The data is recorded to onboard memory and can be downloaded to computer via USB. Also, the data can be monitored live using wireless dashboard. The sensors are sampled 10 times per second. The first results are promising! Although the Pitot/static tubes were mounted in fixed positions, the altitude/speed data is relatively smooth when the head was not moved. The next step is to mount the tubes and accelerometer on a weathervane. This will provide much more reliable altitude/speed readings and with the help of accelerometer, the true L/D can be measured. The goal is to build a system which will provide live feedback to the flyer with accurate L/D and horizontal/vertical speed data. Share your ideas, knowledge, results here! Anyone know Kalman filters? 2007 is going to be a very exciting year! 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! This is interesting: http://www.bicambertechnology.com/technology.htm http://www.bicambertechnology.com/how-it-works.html http://www.bicambertechnology.com/application1.htm Bicamber wingsuits? V-3? 4.0? Yuri Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

With enough kerosene, we will prevail. The skies will be ours. It will become a federal offense to disturb the most rare bird in the universe - WS BASE Homo Sapiens.

We just need a little bit more powerful jet engines. Jump, enjoy the unpowered flight, turn the engines at 200ft, climb up 4000ft and pull over the plateau. Parachute: $2,000. Wingsuit: $1,000. Jet engines: $10,000. The look on ranger's face as you buzz him just 20ft away... PRICELESS.

Got any tips and tricks - on jumping, packing, canopy control, anything - that are not obvious, that you discovered by (no pun intended ) accident or smart thinking? Share! Here's one, "negotiating the shear layer". The tailwind at the exit point was ~10mph, but I knew from the previous jumps off the same object that in the dawn hour the wind on the ground is nil. I used to do 180 into the wind, as usual. The landing area is a long alley of trees which traps the still air, while the air above treetops can be moving at substantial speed. What happens if you cross this shear layer going upwind? If your canopy's airspeed is 20mph and wind is 10mph, you'll enter the still air at 10mph, suddenly loosing 3/4 of the lift. The canopy will dive, the flare will be weak. If you cross the shear layer going downwind, you'll enter the still air at 30mph, giving you a swoopy landing with tons of flare. The "experiment" proved the theory. If your groundcrew reports that the wind on the ground is zero, go downwind (landing area permitting), this way the shear turbulence will work for you, not against you. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

What is the most efficient technique to start flying as quickly as possible from still air exit? Is it an intentionally extended superterminal dive? Is it totally flat? Or somewhere in between? The wingsuit equations can help us understand what works and what not. Let's use the lift/drag coefficients from this post. Although they may not represent any wingsuit, the aerodynamics of the wings at high angle of attack (see, for example, this article) suggests that the lift coefficient is maximum at 45 degrees and is almost independent of the geometry of the wing. Let's model the initial 10s of the flight for the angles of attack 6 degrees (L/D=2.0, Cl=0.26, Cd=0.13, Vxs=132mph, Vys=65mph for some wingloading), 12 degrees (best L/D=2.8; Cl=0.55, Cd=0.2, Vxs=98mph, Vys=35mph), 45 degrees (L/D=0.85, Cl=0.92, Cd=1.09, Vxs=43mph, Vys=51mph), and 70 degrees (L/D=0.35, Cl=0.56, Cd=1.62, Vxs=20mph, Vys=58mph). See StartingToFly.gif. 45 degree technique wins hands down. Due to its high lift coefficient, it propels you forward much more efficiently than even the best L/D AoA. Below 1000ft down, best L/D catches up and soon beats the 45 degree. At these altitudes, the glide ratio is already 1.0 and increasing, so it's time to switch from 45 degrees to full maxed out flight. The headdown and "flat from the start" techniques are the least efficient. StartingToFlyVsWingloading.gif shows how wingloading affects starting to fly. The distance you fly in the first few seconds is inversely proportional to weight. (This explains Deadmanwalking's amazing discovery. ) The bigger the suit, the faster it starts to fly, even if it is not the best L/D suit around. Conclusions: - to start flying as quick as possible, maintain the 45 degree angle of attack in the first ~6s into the flight. Maintain the balance using the leg wing and decrease the pitch angle in sync with the increasing glide until you reach your maxed out pitch. - light flyers start flying faster - the bigger the suit, the easier it starts to fly. Phantom will start flying faster than Prodigy, Vampire faster than Phantom, squarrel suits will fly faster than Vampires. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Ever get a balloon or base jump when it feels all too good... you max out the suit, and you effortlessly fly at insane glide ratio, you experience the quietness and smoothness you've never experienced before and can't figure out what the hell is right? You may think that increased concentration and strength made you fly better. Well, now you can praise basic aerodynamics instead of praising yourself (or clown shoes)! The wingsuit equations are solved in the attached spreadsheet using the simple Euler integration method for some sustained horizontal/vertical speeds (which, as we saw, determine the adjusted lift/drag coefficients). For simplicity, we assume constant Cl and Cd (that is, the wingsuit geometry and angle of attack are constant) and zero-speed exit. You can change the values of Vxs and Vys to match your speeds. In this particular example, Vxs = 86mph, Vys = 43mph, L/D = 2.0. The graph PlaneoutTheoryVsExperiment.gif compares the calculations with one of the Phantom flights (the above parameters were chosen to best fit the experimental data). As you can see, from about 12 seconds to 24 seconds, the glide ratio is higher than 2.0 - we have a planeout with maximum glide ratio as much as 35% higher than the sustained glide ratio. The graph PlaneoutVsWingloadingAndLD.gif shows the dependence of the planeout duration (time period when glide is better than L/D) vs. wingloading. The heavier flyers experience longer planeouts which start later. The graph of glide ratio increase vs. L/D shows that the planeout effect dramatically increases with the increasing L/D: the better you fly, the more you can be fooled into thinking that your insane glide ratio is your L/D. PlaneoutVsLD.gif shows the trajectories and glide ratio vs. time for different L/D. Unlike intentinal dives and spirals and subsequent high-speed planeouts with quite high g-forces in skydiving, the smooth transition into full flight on a base or balloon jump hides the planeout in virtually unnoticeable ~0.1g decelerations that bleed your speed ever slowly, but do make your glide substantially better than your actual L/D. In conclusion, - when analyzing GPS data from a base or balloon jump, discard the first ~30s of the flight, even if it has a linear portion that looks like a sustained flight... it's not! (or better yet, correct the glide ratio for acceleration using the formula above) - planeout effects can also manifest themselves when you change your body position and feel the decreased fallrate and improved glide - only to lose it in a few seconds. It could simply be a planeout! (again, accurate acceleration data can help you see if the improved glide was real or "fake") - after the planeout, you will experience temporary "drop", a decrease of glide ratio even below your L/D. Plan your "do it or die" jump accordingly. - heavier jumpers will experience the planeout effect longer. Vampire will exhibit stronger planeout glide imrovement than Prodigy. The higher the performance, the better the planeout - and the worse the "drop" after it. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Imagine a weathervane attached to the flyer, with a 2-axis accelerometer installed on the vane, with one axis parallel to the vane and the other perpendicular. What will the acceleromer read? The vane is oriented at the glide angle A to horizon. In sustained (zero-acceleration) flight, the components of gravity parallel (g1s, the reading of the first accelerometer) and perpendicular (g2s, the reading of the second accelerometer) to the vane will be g1s = g*sinA and g2s = g*cosA , with cosA/sinA = G (glide ratio). Therefore, for sustained flight, L/D = g2s/g1s. In non-sustained flight, the horizontal ax and vertical ay accelerations will skew the readings (lazy to draw a diagram, figure it out yourself): g1 = g1s - ax*cosA - ay*sinA g2 = g2s + ax*sinA - ay*cosA Hence, g2/g1 = (g*cosA + ax*sinA - ay*cosA)/(g*sinA - ax*cosA - ay*sinA) g2/g1 = (G*(g - ay) + ax)/(g - ay - G*ax) Compare to the formula in the post above. OMFG… The right hand side is equal to nothing but L/D! L/D = g2/g1 Isn't it amazing?!

When speed has not yet reached the sustained value or when we change body position, the current glide ratio is not necessarily equal to L/D ratio. And it's L/D that determines the sustained glide ratio, and that's the value we strive to increase. Can we figure out L/D from the current non-equilibrium glide ratio? The current glide ratio G is equal to Vx/Vy. Let's solve the wingsuit equations for Kl and Kd and then we can determine L/D = Cl/Cd = Kl/Kd. Kl*Vy - Kd*Vx = ax/g/V Kl*Vx + Kd*Vy = (g - ay)/g/V The solution is Kl = (Vx*(g - ay) + Vy*ax)/g/V^3 Kd = (Vy*(g - ay) - Vx*ax)/g/V^3 thus L/D = Kl/Kd = (Vx*(g - ay) + Vy*ax)/(Vy*(g - ay) - Vx*ax) and finally L/D = (G*(g - ay) + ax)/(g - ay - G*ax) If we have accurate glide ratio and acceleration data, we can calculate the true L/D even for non-sustained flight (dive, starting to fly, planeout, etc.) by using the formula above. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Without horizontal windtunnel, how do we know the coefficients of lift Cl and drag Cd? Fortunately, the answer is, we don't necessarily need to. Suppose in some fixed body position your sustained horizontal and vertical speeds are Vxs and Vys. Since for sustained flight acceleration is zero by definition, the wingsuit equations read k*Vs*(Cl*Vys - Cd*Vxs) = 0 k*Vs*(Cl*Vxs + Cd*Vys) = g We have 2 equations for 3 unknowns (k and Cl, Cd). But note that if we combine k with the Cl and Cd into "adjusted" lift and drag coefficients (no longer nondimensional) Kl = k/g*Cl Kd = k/g*Cd we have 2 equations for 2 unknowns: Kl*Vys = Kd*Vxs Vs*(Kl*Vxs + Kd*Vys) = 1 The solution of these is: Kl = Vxs/Vs^3 Kd = Vys/Vs^3 With these adjusted coefficients, the wingsuit equations are dVx/dt = g*V*(Kl*Vy - Kd*Vx) dVy/dt = g*(1 - V*(Kl*Vx + Kd*Vy)) Now the unknown wingsuit parameters (wingloading mg/S and aerodynamic properties Cl, Cd) are "hidden" inside coefficients Kl and Kd, which can be easily calculated from sustained horizontal and vertical speeds. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Consider forces acting on a flyer. One is gravity m*g, another is aerodynamic force that can be broken into two components: lift L perpendicular to current speed V, and drag D opposite to V. If the current glide angle to horizon is A, the horizontal components of lift and drag are L*sinA and -D*cosA, vertical -L*cosA and -D*sinA. Therefore, Newton's law gives us two equations: Fx = m*ax = L*sinA - D*cosA Fy = m*ay = m*g - L*cosA - D*sinA where ax = dVx/dt, ay = dVy/dt are horizontal and vertical accelerations, Vx and Vy are horizontal and vertical speeds. According to aerodynamics, lift and drag can be expressed as L = (1/2)*Cl*ro*S*V^2 D = (1/2)*Cd*ro*S*V^2 where Cl and Cd are nondimensional coefficients of lift and drag, ro is density of air, S is effective area of wingsuit. Since sinA = Vy/V, cosA = Vx/V, after some refactoring we arrive at these differential equations: dVx/dt = k*V*(Cl*Vy - Cd*Vx) dVy/dt = g - k*V*(Cl*Vx + Cd*Vy) where k = (1/2)*ro*S/m, V = sqrt(Vx^2 + Vy^2). Note that the lift and drag coefficients themselves can be changing with time. For simplicity, the surface area is presumed to be constant. These equations can also be applied to tracking, canopy flight, etc. - any non-powered, not spinning out of control flying body. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Yo! Wingsuit flying lends itself to some simple, yet elegant and powerful math. By analyzing the equations of motion, we can try to find answers to questions like: - how can L/D be calculated from the glide ratio in non-sustained flight modes? - can a true L/D meter be built to give the pilot instant and accurate feedback? - why on BASE and balloon jumps you seem to fly better? - how to start flying as quickly as possible on base jumps? - what is the altitude used up before you're flying at full glide? - is bigger better? - how does wingloading affect various characteristics of flight? (including "perceived" performance) - how does balance affect the performance? (controversial, not completely researched, and partially wrong example here; another example of balance derived from windtunnel data here) - how to achieve maximum horizontal speed possible? - why sometimes you seem to be stuck and barely moving forward? Let's see! 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 passengers don't have to land with the plane, right? Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

It was 72mph average several hours ago, with 117mph gusts. I'm sure Lurch can match 72mph with his gigantic Caterpillar boots. Lurch... where's Lurch???????? (He lives just an hour away from Mt.Washington...) Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Exactly. It would be cool and hillarious if a smart, able, and humble kid takes all the candy from energy drink babies, without actually giving a shit about it at all. Land wingsuit, fly through an arch, do a baton pass with a skier, etc. The wind on Mount Washington right now is 72mph. On Monday it was 140mph. A 100mph wind up the 30-degree slope has a horizontal component of 87mph and vertical 50mph... do the math Maggot??? Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

"As far as we know, there are only ten natural arches in the world that have spans longer than 200 feet. All but one of these are in the Colorado Plateau area of the United States. Although there may be other natural arches this long somewhere else in the world, no others have so far been confirmed. The most likely candidate is Tushuk Tash (Shipton's Arch) in China, measured at 1200 feet high, making it the tallest natural arch in the world." http://www.naturalarches.org/big9.htm Arches for any taste! Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Although I've never flown any tracking suit (but flown Prodigy pants a lot, which do not exhibit any stability problems), let me make a guess about the nature of these problems: the legs and arms are not in full contact with the inflated "balloon", which allows the latter to wobble (move separately from your body). Tracking suit stability can benefit from additional points of contact between body and outer fabric by means of, for example, inflatable inner cells. Robi? Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Nah, that's weak. Proximity flying is soo 2006. The 2007 rage will be flying through arches. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Agreed. Landing wingsuit is a piece of cake. A snowy mountain slope at ~25-30 degree angle, and sustained wind up slope with horizontal and vertical components matching your speed is all you need. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Maggot, be careful with black holes! "A black hole is an object predicted by general relativity with a gravitational field so strong that nothing can escape it — not even light. A black hole is defined to be a region of space-time where escape to the outside universe is impossible. The boundary of this region is a surface called the event horizon. Nothing can move from inside the event horizon to the outside, even briefly." Also, remember: Black holes have no hair!!! Look at this guy, he studied black holes! Learn from his mistakes! Use your manequins as test jumpers and proceed with caution. Call me from black hole, that will prove information can escape from black holes and we'll win the Nobel Prize! Yuri Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

To verify the theory of bottom skin expansion, one could make the following experiments on a windy day: 1. Pinch the nose cells and try to kite the canopy. Does it expand? 2. Fold the overhung tops of the nose cells inside and fix with tape to make the nose "straight", with no overhang. Present the canopy perpendicularly to the wind (so that it passes parallel to nose openings). Does it expand? I think even without doing the above, it's clear that the canopy will just bunch up and flap like an old rag. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio