Flying AdHoc Network

The first time I heard about FANET was at a gathering of some paragliding friends last year. They mentioned that they can display each others position on their flight computers. While that sounds cool, I don’t often get to fly cross country any more. Thus this feature was not of particular interest to me. Then some months ago I read an article about the Skytraxx 3.0 in a paragliding magazine. It was mainly focused on the builtin database of aerial obstacles, namely dangerous cables. But it also mentioned that weather stations could broadcast wind information on FANET, which the flight computer would then display in real time. Now that was more interesting to me. The part I like the most about the FANET technology is that it is an open LoRa mesh network. I watched a video where the developer explained that it is even possible to transmit landing procedures based on wind direction to be displayed on the flight computer. Further pilots can send messages to each other, and change the mode from “flying” to “retrieve car” or “need a ride”. All of this together was too much to ignore.
While FANET was developed by Skytraxx, it is an open protocol, and other companies started including support for it in their devices. The Skytraxx devices that come with FANET, also include FLARM. FLARM started as collision avoidance system for sailplanes. But in the meantime, most light aircraft are equipped. Devices for paragliders only transmit to FLARM. They are unlikely to crash into one another due to the slow speed. But by transmitting their position, faster aircraft can be warned soon enough about their presence. Like FlightRadar for big airplanes there is GliderNet based on FLARM and SkyNet based on FANET. These sites are fed by ground stations that decode the signals broadcast by the aircraft. All you have to do in order to appear on these sites, is register with the Open Glider Network. If you register in addition with LiveTrack24 and link your OGN registration (the FLARM id), then your flights are automatically archived. What I like most about this, is that I can give the URL to my beloved ones. If I’m not home in time, they can check if I am still airborne, and where my last recorded position was. So in the improbable case of an accident, they could send search and rescue in the right direction.

How I wrecked the new glider by flying into a cable

We went skiing to Stoos lately. From time to time I went up to the Fronalpstock with the kids. Every time we were up there, I checked the conditions for paragliding. Every time, the wind was blowing from the back. Not very strong, but if it is from the wrong direction, it can be too much rather quickly.
When the day was almost over, I figured that I could also go to the Klingenstock, which is better shielded from southerly winds. When I reached the summit, there was virtually no wind at all. As the sun was already quite low, I could not spot some cables that I knew from the past. I knew I had to be especially careful.
I don’t fly at the Klingenstock very often, only once in a couple of years. The last time was with the speed wing, and I started close to the top on the west side. With the speed wing, I just glide with the skis and the glider comes up pretty quickly. I didn’t want to stretch the lines that quickly with the fragile single skin glider. That is why I descended a bit to a more flat area. I took off from there with a regular paraglider many years ago.
Now the single skin has a worse glide ratio compared to a regular glider. This is why after take off and flying straight for a while, I realized that it would get tight with clearing a small hill in front. My first reaction was to avoid it by flying left. But then I would cross the ski slope with very little ground clearance or possibly even having to land. This is not only forbidden, it can also be dangerous in some cases. So I decided to fly around the small hill on the right hand side. Thus I made a right turn of approximately 90 degrees.
And there it was. All of a sudden I saw a cable right in front of me frighteningly close. I had no time to think. Call it instinct or muscle memory, I immediately continued the right hand turn as hard as I could, to fly back to the slope. For a moment it looked almost as if I could clear the cable and perform a slope landing. But when I was only about 5 meters above ground, the upper left part of the lines connecting the glider to the harness collided with the cable. My forward movement came to a halt, and I slid down gently into the soft snow. Along the way down I could hear lines snapping and the fabric ripping. I was not injured or even hurt, but the glider looked like a wreck. I sent it for repair. But it turned out that it was a total loss. The glider was only two months old and had less than ten flights. Bad things always happen when the equipment is new! Like when I was ground handling a brand new glider 15 years ago, and a RC airplane hit it.
This was the most severe incident in my 17 years of flying with more than 2’200 flights.
In the aftermath it is always important to analyze what went wrong, and what I should have done better.
The first and most important thing is that I was not hurt. But could I have saved the glider?
To save the glider after I saw the cable, I could stall or spin it. That way I would hit the ground before the cable or slip under it. But these procedures induce a pendulum moment and/or spin movement. This is not what you want close to the ground. The risk of injuries would be way too high. In school we learned that some people overreact in this sort of situation, and involuntarily stall or spin the glider. This often results in injuries. So I am relieved that my instinct reaction was just right. I would act the same way if I had the time to fully evaluate the situation.
If my reaction was correct after the fact, what could or should I do better that it couldn’t happen in the first place?
The easiest answer would be to look out carefully for any sort of obstacles. The bad part about this, is that I actually did that.
The next would be to inform about a flying area before going there. When leaving home, I expected to fly from Fronalpstock which I know fairly well. And even if I considered flying from Klingenstock, I don’t think I would look up the map with aerial obstacles, since I was flying there before. But maybe I should.
Cables can be dangerous also for other aerial vehicles like helicopters. There are efforts to remove cables that are no longer in use. So I asked the corporation that owns the land about the cable.
In the meantime I already received the replacement, which is the exact same model of single skin paraglider. Last weekend I used the new glider for the purpose that I bought it for : run and fly. I ran halfway up the Urmiberg an flew down.

Run and fly with the XXLite2

Before I participated in the rollibock trophy in Fiesch last October, I thought my paraglider equipment was fairly lightweight. The glider is a regular Mac Para Marvel, but the Advance Lightness 2 harness is optimized for weight as the name implies, as well as the accompanying backpack. With helmet, gloves, sun glasses, flight computer and clothes, the equipment is slightly less than 14.5kg. When I started paragliding in 2002, a normal equipment was about 20kg. For reference, My tandem equipment is around 30kg, and my competition equipment also was in that ballpark.
When I looked around the participants at the rollibock, I was astonished by the small and light backpacks they had. They were literally running up the mountain. When single skin gliders were first released, it didn’t spark my interest. They were a strange appearance, and the flight characteristics looked slightly frightening to me. But a lot has improved since then. Some models have tubes along the leading edge, others from front to back. They have a lot better characteristics and performance than the first models. I started my research in the internet. Some models weight only 1kg.
Best of all, I started thinking how cool it would be to combine hill running with paragliding. I try to run once a week from Brunnen to Morschach and back. Depending on my daily condition, I make it up to the cable car, or I turn around shortly before I reach Morschach. I always prefer running uphill. Especially since I started getting cramps in my forearms on the descent, sometimes even extending from there. It only happened on longer tours, and only on the descent. After a while I found out that it was caused by dehydration, and I took detours to water sources. I didn’t want to carry anything when I go running. But carrying an ultra light paraglider is something entirely different.
So I asked the loal flying school for an Ozone XXLite 2 glider for a test flight. November is the worst month for flying in Switzerland. The weather is mostly bad with lots of fog, and most cable cars are closed for revision. When the weather was finally flyable, somebody else grabbed the wing already a couple of times. In early December, I finally got to try it. I didn’t really know what to expect. Some people I talked to, praised single skin gliders as great and fun, while others dismissed them as falling out of the sky like a stone. I completed two flights from the Rothenflue. Take off was very nice both times. With the slightest blow of light wind, you can bring it above the head and maintain it there. Also without wind it was easy to get airborne. The handling was surprisingly similar to a regular paraglider. It doesn’t flare as well as a regular wing, but it does flare somewhat. I didn’t know beforehand, but most single skin gliders apparently don’t flare at all. Apart from the handling, I was mostly interested in the performance of the glider. Of course it was not made for performance, and is far from regular gliders in that respect. The teacher from the school providing the glider told me to expect something in the range of a school glider at the time I started flying. When I checked my XCTrainer in the air, I mostly saw glide ratios between 6.5 and 7 with speeds around 35km/h. For comparison, my regular glider has a glide ratio of around 9 and a current high end comp glider is slightly above 10. The trim speed again seems to be different from other single skin gliders that apparently mostly fly less than 30km/h.
My resume after the first two flights was that the flying characteristics are good enough, and the small and ultra light package is just astonishing. In short, I ordered one on the same day. Luckily the forecasted delivery time was was much shorter than I expected.
A week after ordering, I picked up the new wing including the super light harness that I didn’t see before. Of course I bought the glider at the flying school where I can pay with Bitcoin.At home, I installed the special lightweight carabiners and the speed system. But the weather really didn’t look good. We had occasional rain and very strong wind for days. I added a ribcap and gloves to the kit. With this addition, the backpack now weights 1.8kg.
As the first chance of getting good enough weather, I went to the Zugerberg. Instead of the usual walking to the takeoff, I ran. The light backpack really doesn’t bother at all. Even with light wind from behind, the glider took off flawlessly. The gliding ratio was enough to clear the trees halfway down. When I started paragliding, some school gliders had to land before the trees here because they didn’t glide good enough. Also the landing was smooth. The only thing that was strange was the cold wind flowing around my butt. Usually it is very comfy in my cocoon harness. The equipment is packed rather quickly into the backpack, and I was ready to run up to the train. From the train of course I ran again to the car. So my first flight with the new kit was not a pure “run and fly”, but I can say that it works as I envisioned. Now I’m ready for the real “run and fly” adventures.

Hike and Fly the "Kleiner Mythen"

I used to hike the smaller Mythen at least once a year with a paraglider on the back to fly down. Usually i took the Chaemi route which involves some light climbing. Many times I saw mountain goats, and once I slept near the top. Last year I didn’t make it, so I wanted to revive the tradition. Last Thursday I sent messages to some friends asking who would join. Pascal came. With good company the whole trip is even more pleasant. Just before we reached the summit, the fog came in and blocked the view in takeoff direction. We decided to descend. We almost reached Zwischenmythen when the fog lifted. So we hiked up again. The reward was a gentle glide into the sunset. I appreciated every second of the flight a lot more then if I went up with a cablecar.

DCIM103GOPRO

The legacy banks in Switzerland

Transaction costs

I have a separate bank account for my tandem flying hobby at the local bank where I live. I didn’t want a plastic card for it, and setting up online banking turned out to be too complicated. So I pay a CHF 3.00 fee for every withdrawal at the counter. That is, if I go to the branch at my home town.
But last week I wanted to withdraw some money near where I work, less than 30km away, at a branch of the same bank. The teller told me that he would have to make a phone call to the other branch, and that the transaction would cost CHF 10.00
That was too much for me. Considering that a bitcoin transaction to Australia (16’000 km) costs CHF 0.02, the transaction cost of the retail bank per km is more than 250’000 times as expensive as that of BitCoin.

Communication

In Switzerland we usually don’t tell each other how much we earn, or how much we have on our bank account. Swiss Banks even had a reputation of secrecy up until recently. Naturally when you communicate with your bank, you expect this to be confidential. So I asked my bank representative for his public key some years ago, so that we could exchange encrypted emails. His answer was that I would have to use the messaging in the online banking platform in order to enjoy encrypted communication. I strongly dislike to have to log into different web platforms in order to communicate with different people. Some banks even communicate with their customers through centralized unencrypted social media, thus voluntarily introducing a man in the middle. I just had to accept what they offered for the time being. Hence I used this messaging system to cancel my credit card last year. He asked me if I wanted to cancel right away, or just not renew it when it ran out in a couple of months. I opted for the later. But then it was renewed nonetheless. So I asked what went wrong, and to please fix it. The answer was, that I didn’t specify when to cancel. Of course I did! Whether the message disappeared from the system because of some glitch, or was deleted intentionally to cover up incompetency doesn’t really matter. Fact is, the communication channel failed completely. Accountability is an important part of communication. This incident cost a lot of trust that I had in my bank.

Stranded funds

But the story with the cancelled credit card didn’t end there. Because it was not cancelled in time. Some company where I used a service, renewed without my consent. Thus they charged the card that should have been terminated by that time. So I had to send a printed form for the chargeback to the card operator. It took some time, but the money came back to my card account. And for another half a year, I receive a monthly letter stating the balance would be reimbursed next month. I misinterpreted this that it would be automatically sent back to my bank account. But it won’t. I have to send them another signed letter by snail mail to perform the obvious. As if it was 1995, and the electronic signature on my email was not 1’000 more secure than the ink on the paper.
Maybe I’m just spoiled with how well everything works with BitCoin. But the legacy banks really could do a better job.
Companies that deal with BitCoin usually:

  • Have competent and responsive customer care
  • Offer real two factor login with hardware tokens
  • Encrypt and sign the eMails with OpenPGP
  • Execute transactions instantly, not only once per work day
  • Have reasonable fees, even if the volume is still ramping up
  • Care about the usability of their platforms

And where they have limitations, they are usually imposed by the legacy financial institutions.

Back to Mac (nothing to do with Apples)

After I stopped flying in competitions, I also slowly stopped flying competition gliders. So I went back to my old and proven sports class glider. I meant to replace it for a long time. But as my Gradient Aspen 1 is by now more than eleven years old, there really were no more excuses.

So, I took the time to test new gliders. The first one I tried was the successor, the Aspen 5. It felt familiar and comfortable. They also have some good results in sports class competitions. So I almost bought one.

But I wanted to try at least one other model. The most obvious was to see what Mac Para has to offer. After all most of my competition gliders were from MacPara, and I still consider the Magus 4 the best glider I ever flew. The description of the Marvel sounded good, but the model is more than two years old. So I asked if the successor is imminent. Most paragliding companies don’t announce the new models in advance, as they still want to sell the old one. I still expect a successor next spring the latest. That is probably the reason why I got such a good deal for the demo glider. Since I don’t fly cross country as much as I would like to these days, I don’t need the latest and greatest. Instead a glider that I am comfortable with, and that lasts for another decade. Ah and there is another factor. I still like the design of the MacPara gliders. When I was collecting information on the Mac Para switzerland webpage, I was pleasantly surprised to see a picture of myself and my Magus 4 over the pre pyrenees at the 2006 pre World Cup.


Paracuda walk & fly

In the Paracuda paragliding club, we distribute the organization of the events among the members. So I agreed to organize a “walk n fly” event in October. Usually pilots go up with a cablecar to go flying. This saves us from having to carry the equipment for too far. But for people that want to do a bit more sport and see a bit more from the nature, there is “walk n fly”. It’s the perfect undertaking for autumn, where the thermals vanished and the temperatures retreat. The interest was stealthy from the start, but I still hoped some people would join. To my dismay, I was alone on the meeting point.  That didn’t stop me from going to hike though. The Wasserberg was covered in a cloud, and the description in the Internet described the trail as difficult to find. So I save this one for later. Instead I went to the familiar Pfaff near Glattalp. About once a year, I take the cablecar to the Glattalp, and do the half hour hike to the Pfaff. It has a huge take off area with two possible directions. After I was airborne, I headed straight to the Kupferberg with a nice little cloud atop. As I approached, the birds left, and apparently the thermals as well. So I went to the next one. This was the mountain straight on top of where my father grew up. I remember looking up the wall when I was a kid, visiting my grandmother. It looked enormous from below, but at the hilltop looks very friendly. It even spared some thermals for me. In October late afternoon it’s already very nice, if you can hold your position for a couple of minutes. After cruising around in the Bisital some more, I landed right behind my uncle’s cows. That was actually the most difficult part of the flight. There is a tight grid of power lines, and only from atop I could spot a cell big enough to squeeze into. I had a coffe at my cousin’s house, and then hiked back to the car. The signs indicated more than an hour, but actually it takes only slightly more than half.

 

Generating flight vouchers with LaTex

Learning LaTex was on my todo list for many years. Like most people of my generation, I learned wysiwyg text programs in school, and used them for a long time for most stuff that ended up on paper. Actually, to be exact, the first text processing program I learned in school didn’t fall into the wysiwyg category, but was DOS based. I think it’s name was “Farsight”, but I can’t find any information about it on the internet. Since I am no friend of proprietary lock-in systems, I switched from MS Word to OpenOffice a long time ago, and more recently to LibreOffice. But even though their file format is open, it’s still binary. I know, I know, Word and ODF offer textual formats. I think they are mostly XML based. But the last time, I looked at one of them, I could not believe how overloaded with useless trash they were. The most annoying limitation of binary formats, is when you want to store the documents in a version control system, and compare different revisions. I used html for a while for documentation purposes. Although it is very good for these textual diffs between revisions, I’m not artistic enough to make it good looking. Hence, I thought for a long time that LaTex would be worth learning.

Also, for a long time I wanted to automate the vouchers for our tandem flights at paraeasy.ch. Even-though I knew that this was a perfect match, I had too many other things to do. As I’m currently reading a book about LaTex, I have my perfect hands on exercise. Hence, I prepared a template tex file for the vouchers and one for the invoices. Then I wrapped a python script around, that handles the rest.

The traditional way to keep track of which vouchers are active, and which ones were redeemed, is to keep a list. But after reading all the buzz about smart property, I figured that BitCoin is actually a perfect solution in itself. I generate a unique BitCoin address for each voucher, and load it with some coins. That way I can easily check, if the voucher is still valid. In fact, even other pilots that fly for us, can easily verify the validity of our vouchers. Now the perfect solution would be to load it with the full value, but since the BitCoin price is still quite volatile, the risk would be too high. After all, I need to be able to pay other pilots in case of a BitCoin crash. So I decided to load the voucher addresses with half the value. That way I can better tackle the risk.

As an opensource believer, I pushed my scripts to github, hoping they might be useful for somebody. I didn’t go to full lengths, in making it a configurable drop in solution. So, if you want to use it, leave me a message, and I will help you set it all up, and make it more configurable along the way.

Now, what happens if somebody orders a flight voucher on paraeasy.ch?  After the customer fills in all the required fields, and presses submit, I receive an email with a html table containing all the information. I then save the mail with evolution to a folder as an mbox file. Next, I start the python script which performs the following:

  • Generates a new unique number for the voucher.
  • Parses the information from the mbox email file.
  • Generates a BitCoin address that contains the initials of the passenger.
  • Replaces the placeholders in the tex files with the actual information.
  • Generates a qr code with the relevant information, and a gpg signature thereof.
  • Generate pdf files for the voucher and invoice.
  • Add the new entry to the list of active vouchers.
  • Add the pdf files, the updated list as well as the encrypted private key for the BitCoin address to my private git repository.

The system is not finished yet, but it already looks like a big relief. In the future, it might also generate the email to send the pdf file back to the customer.