yuri_base

Version 2.0 [inline LDVario_v.2.0_EN.png] L/D Vario is now a complete flight instrument, measuring the most important aerodynamic parameters of the gliding flight: lift-to-drag ratio, air glide ratio, current horizontal and vertical airspeeds, and sustained horizontal and vertical speeds normalized to sea level (a.k.a. the polar curve). Advanced multiple-layer algorithms are used to calculate smooth descent rate and vertical acceleration from noisy altitude data. Wingsuit Equations are solved in real time using accelerometer and barometer (or GPS) data to measure flight parameters and provide instant visual and audio feedback. Use of devices with high-speed barometric sensors (60Hz or faster) is highly recommended for the feedback lag not to exceed 0.2s. Android+Wear iOS Windows Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

L/D Vario is now available on Apple devices! Choose your weapon: [inline AndroidStore-EN-172x60.png] [inline AppleStore-EN-202x60.png] [inline WindowsStore-EN-231x60.png] Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

L/D Vario is now available on Windows devices! Windows 10 is required as earlier versions do not support pressure sensor. https://www.microsoft.com/en-us/store/apps/l-d-vario/9nblggh22jwg Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

- made app load much faster - removed the inclusion of x-component of apparent gravity in z-component upon more research - reduced the aggressiveness of the low-pass filter and limited max L/D to 10 to improve responsiveness Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

I thought I'd share some pitfalls that I encountered during R&D so other people won't repeat them. With the iPhone vane mount I jumped before (https://vimeo.com/132279770) there was one significant issue: vibrations. Vibrations introduce a lot of noise to accelerometer readings. These vibrations come from body movements (slight pitch and roll movements we don't even notice result in noticeable accelerations at the end of a long pole), breathing (mounting platform moving), and invisible vibrations from turbulence created by the vane itself. With the smartwatch mount I've been working on, I wanted not only to make the whole system lighter and creating less parasite drag, but also solve the vibration problem. So I thought, instead of a rigid stick (that blue pole is a telescopic hiking pole), something flexible - like a fishing rod - would damp the vibrations well. Also, suspending the vane on a thin rope instead of a rigid axis should also help. But as it turned out in testing, both ideas were wrong: rope only increased the wobbling, so I returned to rigid suspension axis; and the fishing rod - compared to rigid pole - also only increased the vibrations, as it happily dances in the wind. This dancing makes L/D measurements unusable. So, going back to rigid pole and rigid axis... Hope this helps folks building their own vanes. Any suggestions are welcome. Perhaps someone with an engineering experience of damping vibrations can chime in? Video: https://www.youtube.com/watch?v=dPZ02IGk78Y (For some strange reason, all 3 jumps with the fishing rod resulted in linetwists - same direction and amount. Go figure.) Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

- added support for GPS altitude if barometer is not present - improved timeliness of speech generation: if by the time the first digit is finished being pronounced the second digit changes, the "fresh" second digit will be pronounced instead of the old one - tone is now playing in the left stereo channel, speech in the right Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

- added speech generator - eliminated audio clicks in tone generator Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

L/D Vario now supports 6,666 different devices running Android 4.1 (Jelly Bean) and higher. Almost 90% of total number of devices in use are now compatible. (Please let me know of any issues with layout or functionality on 4.1-4.4 devices, as it's impossible to test everything.) So, now you can use some old Android device you had collecting dust in a drawer, as your dedicated L/D variometer. Remember the old discussions circa 2005-2009 (before facebook ate people's brains) we had in the forums on how to measure L/D? How to compensate for the wind? How to achieve best L/D? Remember claims of 7.0+? People are still looking at the GPS graphs and can't figure out what they're looking at, as glide ratio in general is not equal to L/D. Glide ratio of modern wingsuits can be anything - from 0 to positive infinity and through singularity to negative infinity to some negative number (when gaining altitude during flare). L/D is a true measure of aerodynamic finesse of a flying craft and has a hard ceiling. Nobody in the world has L/D higher than about 3.0-3.1 in wingsuit. The glide ratios of 5.0 you can see in competitions are simply results of insane upper winds, superslow fall rates, and milking of the initial high speed gained during a steep dive. Now we can stop fooling ourselves. The problem is FUCKING SOLVED. Fly smart! https://play.google.com/store/apps/details?id=com.PFM.LDVario Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Lowered the minimum Android version to 4.4 (API 19) for the mobile app and to 4.4W.2 (API 20) for the wearable app. https://play.google.com/store/apps/details?id=com.PFM.LDVario Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

L/D Vario is an Android + Android Wear app for wingsuiters, trackers, canopy pilots, paragliders, etc. (any gliding airsport) to help maximize your flying performance. It is a much simplified version of L/D Magic for iOS. [inline AndroidWear.jpg] The app is based on "Accelerometer-Vane Principle" and uses the accelerometer in your device to accurately measure Lift-to-Drag ratio (L/D) and provides instant visual and audio feedback. To use it, your device needs to be mounted on a vane that is positioned in undisturbed air stream (away from the body/wing at least 2-3 feet) and is precisely aligned with the relative wind at all times, so that its Y-axis (from screen bottom to top) is parallel to the relative wind, and X-axis (left-right) is parallel to the ground. Similar to what you can see in these videos: vimeo.com/108428363 and vimeo.com/108326309. Now with Android Wear watches, the device can be made quite small&light and less obtrusive compared to a phone on a vane. [inline LDVarioBanner.jpg] Unlike GPS that measures ground glide ratio (which is distorted by wind and dynamic maneuvers such as dives and plane outs), L/D Vario measures true, instant L/D — your aerodynamic finesse — independent of wind and dynamic distortions, so you can maximize your L/D much faster and more reliably. It is also a great tool for airsport equipment manufacturers to develop even higher performing gear and do A/B mod tests directly in flight! Enjoy ---> [inline Icon.png] L/D Vario on Google Play Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

For wingsuiters and trackers, I created an iPhone app called L/D Magic: https://itunes.apple.com/us/app/l-d-magic/id643384086?mt=8 (and for a limited time, Flight Data Recorder feature and additional Kalman Filters are free) It's not a simple logbook, though - it's a scientific application for serious flyers. Example of data (Lift-to-Drag ratio, Glide Ratio, lift and drag forces and coefficients, momentary and sustained horizontal and vertical speeds, momentary and sustained polar curves): [inline Sputnik.png] To get good results, you need an external GPS running at a minimum 5Hz (the app supports Bluetooth GPS Dual XGPS 150A and 160 and plug-in units like Emprum UltiMate GPS and BadElf GPS). For best L/D data, however, nothing beats using accelerometer/gyro with the phone mounted on a vane. A couple of videos to give an idea of what it looks like: https://vimeo.com/108326309 https://vimeo.com/108428363 Yuri Base Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

The SensorTag printed circuit board is the size of two quarters side by side, and weighs nothing. If I were to do it, I'd make a tiny pouch from thick fabric or leather and attach it with a few hand stitches to an inner rib (if you look at crossport cuts, you'll see some fraying - manufacturers dod't even bother embroidering the edges, because the stress there is small enough; making a few stitches there to hold a 5-gram PCB won't weaken your parachute). Of course, you'll need to be careful when packing as not to snap the PCB. For the second sensor, I'd make some kind of miniature sock or cotton ball that will equalize the pressure so it won't measure the stagnation pressure, but rather ambient, and mount it between frontriser links after opening. I believe TI's app is able to pair with several sensors at once (but you'll need to switch between screens to read each). I have two SensorTags (which I bought with the purpose of making a Bluetooth Pitot tube for L/D Magic), so I'll gladly answer any questions about them. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

You can find this out yourself with a couple of SensorTags for a cost of two jumps. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

I've found that 2 feet is the absolute minimum to get accurate airspeed and glide measurements. The more, the better. Good (L/D Magic): Good (Analog L/D Meter): [inline AnalogLDMeter.jpg] Bad - too short (~12"), recorded airspeed was only ~70% of the actual, and exaggerated L/D due to relative wind being deflected by body and appearing to be closer to horizontal than it actually is (Z-Device): Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

The almighty iOS 8 broke Help system in the current (1.0.1) version of L/D Magic. (You see an error instead of a document.) Since the upcoming update will jump directly from iOS 6 to 8, as a workaround for now you can download Help files and Kalman Filter model descriptions in PDF format: LDMagic_1_0_1_Help_English.zip (1.2MB) (also available in Russian (1.0MB)) This would have never happened while Steve Jobs was alive. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

This sensor might be of interest to you: Airspeed MicroSensor (they also have data recorder that this sensor can plug in to, as well as wireless dashboard) I've used Eagle Tree products in the past and although it was a struggle to adapt them to my purpose, they might work for you. If you're interested in using your smartphone with a wireless pressure sensor, check out SensorTag from Texas Instruments. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Can you design and mass produce a good vane mount for a smartphone? (to get an idea, watch 1, 2, 3 (fail)) [inline LDMagicVane.jpg] Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Tuomo, shoot me an email at ldmagicapp (this is a gmail) Yuri Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

TuomoK - YES, I'm always interested in wireless sensors for smartphones and adding support for them in L/D Magic. What's the update rate of the GPS? (I need at least 5Hz, but 10Hz or higher would be awesome.) And what's the price estimate? Here's another inexpensive Bluetooth sensor that has 6 sensors (temperature, humidity, pressure, accelerometer, gyroscope and magnetometer): Texas Instruments SensorTag Alas, it doesn't have a GPS... yet. But the way things are going, smartphones are becoming the centers of computing universe - everybody has them, upgrades them, they have powerful processors and beautiful screens, so the need for external sensors is huge and we see more and more low energy wireless sensors introduced. And while smartdevices themselves have sensors, in many applications it's often best (or only option) to have external sensors. For example, at least some smartphones (ALL iPhones) have GPS that is not usable in freefall - they have such a heavy smoothing/data massaging that they respond to rapid changes in altitude with a huge lag - I land yet it shows I'm still thousands of feet in the air and continue flying for a minute or two. iPhone's internal GPS is not usable at all for freefall data collection/analysis. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

I have a different reason for using Bluetooth aside from "wirehate": wireless is the only option when using L/D Magic's audio feedback with iPhone mounted on a vane (see https://vimeo.com/108326309 and https://vimeo.com/108428363 to get the idea). I tried a wireless headset and closed-ear headphones with no avail - they simply did not provide enough volume to be heard in freefall. So, I've got the following setup: 1) August MR220 Bluetooth Audio Receiver ($10) 2) FiiO E6 Fujiyama Portable Headphone Amplifier ($26) 3) Koss 'The Plug' In-Ear Headphones ($10) This works. I can hear it in freefall just fine. The Koss headphones are cheap yet have very good isolation. (Next I'll try separated closed-ear headphones with this setup to reduce the hassle of putting the helmet on.) The receiver and amplifier are small boxes that should fit inside most of helmets under the foam or in audible pouch. Anyway, since I've spent some time, money, and frustration on finding what works, I thought I'd share. If anyone finds a combined compact Bluetooth receiver-amplifier, please post. OR, if you know any Bluetooth headphones that can be very loud and be heard in freefall, in which case the whole setup above is not needed. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

It's really easy to estimate the drag of the drogue if you measure sustained fallrate with and without the drogue. Ask jumpers doing a practice tandem jump to do this for you using any device that can measure fallrate (Viso, etc.) If without the drogue sustained fallrate is V1, then W = Kd1*V1^2, where W is total weight, and Kd1 is the "magic" coefficient of drag from Wingsuit Equations. If with the drogue sustained fallrate is V2, then W = Kd1*V2^2 + Ddrogue, Ddrogue is the drag due to the drogue. So, Kd1 = W/V1^2, W = W*(V2/V1)^2 + Ddrogue Finally, Ddrogue = W*(1 - (V2/V1)^2) For example, if W = 170+170 + 40 = 380lbs, V1 = 150mph, V2 = 120mph, then Ddrogue = 380*(1 - (120/150)^2) = 137lbs For purely theoretical estimate, without any measurements, we can estimate the drogue-less fallrate of the tandem pair as standard fallrate 120mph times square root of 2 (since drag is proportional to the square of speed, and weight is increased by a factor of 2). Then (V2/V1)^2 = 1/2, and Ddrogue = W/2, which for the total weight 380lbs gives Ddrogue = 190lbs. But with actually measured V1 and V2, the estimate will be much more precise. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

Some modeling shows that the forward throw (relative to airmass) for a headdown jumper can be 200m (~650ft) greater than that of a belly jumper at jumprun airspeed of ~80kts (and even more at higher airspeeds, obviously). Which essentially "eats up" 5 seconds of exit separation. So if you're a belly jumper exiting after freeflyer (at some DZs this order is still the case), count to 5 first, then start your normal separation count. [inline Headdown.png] [inline Belly.png] The old notion that by 10-12 seconds of freefall the forward throw completely stops as if we're falling in glycerin is incorrect: even at 12s, belly jumper is still moving at ~22mph horizontally, and headdown jumper at whopping 44mph! Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

I'll take a pic next time I jump, but there's no difference in the rest of the pack process. You fold the cocoon and put it in the bag exact same way as you usually do. Of course, always make sure the slider grommets are pushed all the way up the lines. Here is a 3.5yo video which helped me first realize what the problem is and how to solve it. It shows "only" a 0.7s (22 frames at 30fps) cocoon hesitation, but I've experienced some 2-3x longer hesitations as well. If you watch frame-by-frame, you'll see that the cocoon stays closed and is dancing, morphing and rotating in the air, resulting in line twists even with good body position. Sometimes, hard openings would occur due to slider grommets sliding down the lines under the wildly dancing cocoon. Note that I never wrap the cocoon tightly - you can see that the top part of the cocoon falls apart in 2-3 frames, while the bottom part (facing earth) stays "glued" to the packjob for the whole 22 frames due to pressure of airflow hitting the pack job at an angle. Yellow is the center cell; orange is adjacent cells; red is side cells and the slider. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

I tried it before settling on the more radical approach - it didn't work. In angled deployment, the extracted cocoon is sagging below the relative wind line drawn from your shoulders, due to its weight. As a result, relative wind is hitting the cocoon not "heads on", but at some angle. The pressure of wind in this case presses the tail of the center cell, which is wrapping the packjob, against the rest of the packjob, making it "stick". A little hole in the apex of a loosely wrapped cone is not enough to overcome this. Android+Wear/iOS/Windows apps: L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP iOS only: L/D Magic Windows only: WS Studio

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