0
yuri_base

L/D Vario

Recommended Posts

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

Share this post


Link to post
Share on other sites
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. B|

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

Share this post


Link to post
Share on other sites
- 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

Share this post


Link to post
Share on other sites
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

Share this post


Link to post
Share on other sites
- 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

Share this post


Link to post
Share on other sites
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

Share this post


Link to post
Share on other sites
A trivial, yet easy to overlook bug in my custom localization engine caused the app crash on launch if system language was not one of the supported languages (English and Russian). Sorry, Frenchies, that you could not flyaii yer bodeé with my app!

The updates are submitted to all 3 stores, however, while Android is already live, iPhone takes ~7+ days for approval (and submitting updates while the previous version is waiting for review resets the clock! what a shame, Apple), Windows ~2+ days. C'est la vie!

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

Share this post


Link to post
Share on other sites
Some news from the development front (may be of general interest for other devs):

B| #1. Impossible is possible: every one of the 4 apps on each platform consists of just one line of code (C#):

Shared.MainEngine.Instance.Initialize(some platform parameters).Start();

That is fucking it!

All other lines of code - thousands of them - in main engine are absolutely platform-agnostic. Of course, the engine links to some libraries, some of them cross-platform (various math, physics, Wingsuit Equations, etc.), some are abstractions from the platform specifics (UI, sensors, sound, localization), but all these libraries are generic and can be used in other apps, so the relative effort of writing them approaches zero in the long run.

B| #2. Localization (text, images, sounds) is also fully abstracted from platform specifics (all these horrible platform-specific ways of localization - *.xml, *.resx, *.strings - make me want to puke as you have to manually copy each string between platforms and escape the special characters), now all resources are in one folder which is simply copied between the 4 projects without any changes. Lovely!

B| #3. The visual designs in each of the 4 projects consist of just one container in the window. That is fucking it! Custom crossplatform layout engine fills this container with all UI elements in such a way that you can't see screen differences between platforms by naked eye, only using bitmap difference in photoshop can reveal small differences caused by slightly different rendering of the same font by platforms - here's the diff between iPhone 5 and Note 4:

[inline PlatformDiff-EN.png]

Sweet!

These are some invisible things behind the seemingly simple app with some numbers on screen. It's magic, pure fucking magic!

Now I need me some well earned beers! ;)
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

Share this post


Link to post
Share on other sites
mxk

Are you using on Xamarin or something similar to maintain a single codebase for all three platforms?



Yes, I use Xamarin for Android/Wear/iOS and Visual Studio for Windows.

Visual Studio can also integrate Xamarin's Android/iOS (you still need a laptop with Xcode to build iOS apps), but for now I run Mac version of Xamarin and Visual Studio in Windows on VMware on a MacBook Pro.
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

0