Aug 03, 2014, 08:59 PM
Soaring Circuits
rcbrust's Avatar
Discussion

GPS Racing Discussion


The purpose of this thread is to discuss the possibility of new electric soaring formats based on GPS telemetry data, with a strong emphasis on the technical side, i.e. the equipment and logistics needed to run such an event.

One example which is already being flown primarily in Europe is GPS Triangle Racing. This format has 1/3 scale sailplanes, either aerotowed or launched with up-and-go's, flying predetermined triangular shaped courses. In a nutshell, you're typically given 30 minutes to fly as many laps as you can and successful flights combine both fast ground covering phases and also thermalling phases to regain lost altitude. A team consists of a pilot and a helper who follows the sailplane's course on some sort of receiver and guides the pilot through the flight. The official flight starts and ends by crossing a starting line (typically at some maximum altitude) so the launch and landing are taken out of the picture.

In my opinion, one obstacle to flying such an event with our ALES style ships is the cost of entry. The GPS systems typically cost in the range of $800 to $1000. Personally, I'd like to see hardware that costs 1/4 to 1/3 this much. I don't think it will ever get down to the point where a GPS based event could have the mass appeal that ALES does, but hopefully we can get it down to where it would appeal to hundreds of people, versus just a handful.

To that end, I am presenting some results from a project I've been working on. I've been playing with triangle racing using a FrSky Taranis and its custom script capability. One script I've written gives you audible cues to keep you on the course, i.e. you can fly it by yourself and don't have to look at the transmitter. Below are 3 laps that I flew today at my local high school using a Radian on a 200m course. I know 200m isn't that large but the Radian doesn't exactly have great legs and it's just a proof of concept. I still have some tweaking to do but it's getting there.

Triangle racing isn't necessarily the only way to go. I just decided to emulate that since it's already an up and coming format in the scale sailplane world. So, let's have at it...

Randy
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Aug 03, 2014, 09:19 PM
Registered User
kcaldwel's Avatar
Randy,

Thanks so much for pioneering this! I hope there are some interesting new tasks that come out of this. I hope to have my Taranis GPS set-up flying soon, although I definitely do not have your programming skills.

One question - when I scale the distance of your course off the length of the tennis courts in the photo, I get two legs about 285m long, with a base leg of about 400m, almost 1,000m around the points of the triangle (about 970m). That is much more than a 200m triangle I think? Triangle course are usually measured by the sum of the length of their sides.

Kevin
Aug 03, 2014, 09:30 PM
Launch high, go long
LostVisual's Avatar
Hi Randy,

I'm all over this one. I attended the Montague Glider Festival this year where a portion of the festival was 3 days of GPS Triangle racing. I've decided to make this a future event for myself but with an electric launch glider. It's a lot easier to practice when you don't need a tow plane or a winch. I bought the T3000 electronics to install in on of my electric glider to practice. You need a special electronics set up because it is used to compute your 'score' for the day from the flight data it collects during your run.

Have you checked out the website Sky Navigator? skynavigator.net The Europeans have used to to score/report event results.
Aug 04, 2014, 05:59 AM
Soaring Circuits
rcbrust's Avatar
Quote:
Originally Posted by kcaldwel View Post
One question - when I scale the distance of your course off the length of the tennis courts in the photo, I get two legs about 285m long, with a base leg of about 400m, almost 1,000m around the points of the triangle (about 970m). That is much more than a 200m triangle I think? Triangle course are usually measured by the sum of the length of their sides.
I'm using the size "standard" that others have seemed to settle on and that is based on the distance from the base position to each of the turn points. If you assume the base point of the course is in the middle of the bottom (long) leg, and for the sake of simplicity let's assume the base leg runs east-west, then for a 200m course, turn 1 is 200m to the east, turn 2 is 200m to the north and turn 3 is 200m to the west. The perimeter of the course (lap) is 0.965km. The big ships fly 500m courses which equate to 2.41km laps.

There's nothing magic about the 200m course I'm test flying with. I chose that size for two reasons. First, to keep me primarily over the school property and second, the Radian is so darn pokey that it takes a while to get around any course. This last trial, I did add about 6 ounces of ballast which helped a lot. I plan on adding more next time.

Randy
Aug 04, 2014, 06:03 AM
Soaring Circuits
rcbrust's Avatar
Quote:
Originally Posted by LostVisual View Post
Have you checked out the website Sky Navigator? skynavigator.net The Europeans have used to to score/report event results.
Yup, saw that. And I agree that any system that we come up with should time and score the flight automatically.

Randy
Aug 04, 2014, 08:35 AM
Flying = Falling (Slowly)
dharban's Avatar
Fantastic!

I am testing the RC 3000 setup right now and agree with your observation that something more cost effective will be needed to get widespread interest. A Taranis based system would probably fit the bill.

One of the things that you need to test for is the extent to which lost telemetry packets effect the use of the system. I have heard some comments that some 2.4 based systems have exhibited problems which materially effected the ability of contestants to get around the course -- especially on the speed run.

Another thing that needs to be determined is where you get to the point where the GPS signal is not accurate enough to adequately differentiate speeds. It looks like the Triangle Racing has pretty well figured this out and designed tasks where the GPS error is small enough relative to the measured task that it works. The F3B guys have been working on this and I am under the impression that the error inherent in GPS is too large to accurately differentiate speeds on the speed runs.

That said, one of the things I have discovered with the RC 3000 is that it is not only set up for GPS Triangle Racing that allows the user to specify the course size and heading, and altitude and speed entering the triangle course -- parameters which are part of the rules -- but it can also be employed for simple speed and distance tasks flown between two imaginary planes.

When you look at the GPS Racing rules it contemplates a 30 minute flight window for the task and this pretty well drives the contest size and administration. On the other hand, having a simple device which can be set up to define two imaginary planes and which will provide a simple audible signal each time a plane is approached and passed would facilitate distance tasks which could be incorporated within a standard ALES format.

One of the things that you might consider in setting up your software is the mechanism that the RC 3000 has available for setting up the principal course heading without an external computer. When you are setting up the course part of the routine simply has you identify your current position and then walk you plane a modest distance in the direction of your principal course heading. That's it.

I really think you are doing a great thing here. I hope it goes well. If I can help in any way, just let me know.

Happy Landings,

Don

BTW: Missed you and Lauren at Polecat. Next year for sure.
Aug 04, 2014, 09:01 AM
Soaring Circuits
rcbrust's Avatar
Don,

Thanks, and please continue to share any experiences you have with the RC3000 system. I'm not trying to limit this thread to just Taranis (or other inexpensive) based systems and I'm not trying limit this to just triangle racing. That's just the approach that I happen to be taking right now, but discussions based on all systems and potential formats are welcome.

Yeah, I'm aware of the course creation feature that the RC3000 has. That's pretty cool. For now, I've created a spreadsheet where you can enter the base location coordinates, the size of the course and the angle and it generates all of the coordinates to define the course. I've been manually entering them into Google Earth but once I have the spreadsheet creating the KML file which can be loaded into Google Earth, I'll post it here so others can play with it.

Randy
Aug 04, 2014, 10:06 AM
Registered User
kcaldwel's Avatar
Quote:
Originally Posted by rcbrust View Post
I'm using the size "standard" that others have seemed to settle on and that is based on the distance from the base position to each of the turn points. If you assume the base point of the course is in the middle of the bottom (long) leg, and for the sake of simplicity let's assume the base leg runs east-west, then for a 200m course, turn 1 is 200m to the east, turn 2 is 200m to the north and turn 3 is 200m to the west. The perimeter of the course (lap) is 0.965km. The big ships fly 500m courses which equate to 2.41km laps.

There's nothing magic about the 200m course I'm test flying with. I chose that size for two reasons. First, to keep me primarily over the school property and second, the Radian is so darn pokey that it takes a while to get around any course. This last trial, I did add about 6 ounces of ballast which helped a lot. I plan on adding more next time.

Randy
Having flown many hang gliding XC courses, and set an FAI triangle record, I know the standard FAI definition of a triangle XC course is the sum of the length of the legs. Defining it by the length of the sum of the sides also allows setting up a bigger variety of triangle shapes to fit particular site requirements.

A 1km triangle sound much better than a 200m one! Why wouldn't you measure a the triangle size by the distance flown?

You flew more XC distance with your Radian, solo, than the teams at the Nationals!

FAI Sporting Code Section SC 3, Sailplanes:

"b. TRIANGLE FLIGHT
A CLOSED COURSE having three LEGS . For triangle record COURSES of 750 km or more, the length of each LEG shall be 25% to 45% of the OFFICIAL DISTANCE . For record COURSES shorter than 750 km, no LEG may have a length of less than 28% of the OFFICIAL DISTANCE. The geometry may be either:
(i)A triangle having two TURN POINTS , or
(ii) A triangle having three TURN POINTS independent of the position of the START / FINISH POINT . The distance is given by the sum of the LEGS of the triangle formed by the TURN POINTS . The minimum OFFICIAL DISTANCE (1.3.9) is 300 kilometres."

Kevin
Aug 04, 2014, 10:52 AM
Registered User
Hi Randy,

this sounds great.

Would you mind supplying the Taranis .eepe file so we can see how you coded it.

Thanks.

Lift,

- Bob -
Aug 04, 2014, 12:26 PM
Soaring Circuits
rcbrust's Avatar
Kevin, the course size gets referred to both ways, i.e. distance to the turns and lap distance. The distance to the turns seems to usually be the round number. Feel free to use whichever you like. The way I see it, when deciding how to refer to the course is our biggest problem, I'll be quite happy.

Bob, it's a LUA telemetry script file, not an .eepe file. It's still a work in progress. I'll post it once I get a little further along. It's currently useless without course coordinates though.

Randy
Aug 04, 2014, 02:23 PM
MrE
MrE
Registered User
Thanks for starting this thread Randy!

I am very interested in seeing your scripts and spread sheet when you're ready.

Being completely clueless on the details of this, is it possible for different pilots to use different hardware and still fly the same "contest" together or is everyone going to have to standardize on the same hardware?

I other words, if I got a Taranis and used your script, could Don show up with his T3000 and easily join us or is there going to need to be a bunch of programming done on one or both sides?
Aug 04, 2014, 02:36 PM
Flying = Falling (Slowly)
dharban's Avatar
While there are many possible GPS applications for ALES flying, the GPS Triangle racing to which Randy refers is described in the attached rules. These are the most recent rules I can find.

In its current context it is flown mostly by 1/3 scale gliders. There are two classes that are flown -- Aerotow and Up-and-go.

Four or more rounds are flown with one round being a speed task and the remainder distance tasks.

Each round is flown within a window which is long enough to facilitate the launching of all of the contestants. Contestants launch inside the window and the objective for the distance task is to fly as many laps of the triangle as possible in 30 minutes (from a single launch).

The speed task is flown like the distance task except planes are timed for one lap only.

Planes are launched to in excess of 500 meters. Planes fly about until they are ready to enter the course at which time the telemetry notes the time, altitude and speed when the plane crosses the line. There are penalties for entering the course above 500 meters and/or for exceeding some predetermined maximum speed. The telemetry keeps track of how many laps are flown and how long it takes to complete those laps.

Planes land in a rectangular landing zone and are required to touch down in the zone in a realistic manner and to come to rest inside the zone.

Scores for each round are normalized to 1000 points.

Upon landing the telemetry furnishes Starting Time, the Task Entry Height, The Task Entry Speed, the Flight Time, the Number of Triangles and the Speed at which the triangles were done. This plus the landing score are entered into a computer and the scoring is done pretty much like any other contest.

This kind of flying is interesting and challenging. And its cost and logistics are pretty much out of the range of many fliers. It can be done with smaller planes, but the scale of the enterprise has to reduced to facilitate being able to see our smaller planes at a distance and at altitude. A lot of what I am testing right now is exactly how the event might be scaled for the gliders that we mostly fly in ALES. The equipment is no problem. The entire RC 3000 system can be fit inside a Maxa fuselage and weights about 1 ounce.

Once Randy and others get the cost of telemetry down a bit it opens the door to a whole new dimension -- literally -- ALES competitions. Contests where distance is a part of the task can be flown without any significant organizational logistics -- just different score cards.

By the way, GPS Triangle Racing at the international level is not an FAI event. It has its own stand-alone organization. But it is becoming very popular and guys who have flown it really seem to like it.

Happy Landings,

Don

BTW: One of the things I am going to experiment with is installing the on-board telemetry in a pod that can be moved easily from plane to plane.
Aug 04, 2014, 06:53 PM
Registered User
wakumann's Avatar
Triangle racing with a Radian or Maxa
just hope there is no wind or get ballast or better fitted models.

The Idea of GPS based recording competion isn't new, neither doesn't require a large investment
https://www.rcgroups.com/forums/show....php?t=1018007

Thomas
Aug 04, 2014, 07:54 PM
Registered User
kcaldwel's Avatar
Thomas,

There are much cheaper GPS data loggers available now:

http://www.ebay.com/sch/sis.html?_nk...d=220781466584

Without telemetry back, you would just be flying random courses, and guessing at distances flown. It is far more challenging to have to fly to fixed turn points.

The "J" planes are doing quite well at XC, albeit with ballast:

https://www.rcgroups.com/forums/show....php?t=2188962


Kevin
Aug 04, 2014, 08:16 PM
Soaring Circuits
rcbrust's Avatar
Quote:
Originally Posted by MrE View Post
Being completely clueless on the details of this, is it possible for different pilots to use different hardware and still fly the same "contest" together or is everyone going to have to standardize on the same hardware?

I other words, if I got a Taranis and used your script, could Don show up with his T3000 and easily join us or is there going to need to be a bunch of programming done on one or both sides?
I believe you can load courses into the T3000. Don may be able to shed more light on this. In my opinion, being able to use different systems would be ideal.

Randy


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