Jump to content

F3F Timer


Rooster-X

Recommended Posts

Yes it worked fine until the laptop battery started suffering and the first thing it did was shut down the serial port connected to the timer to save juice. I'm sure there will be a solution, warmer weather perhaps.The P3 survived the land out OK, just a little embarassment, wet feet and tired legs to show for it. I hope its another 3 years till my next one

Link to comment
Share on other sites

Gonesoaring2003 said:

It appears to be working - but only for George Young grin.gif, I presume they're just setting up at the mo!
I flew first today and just after I landed I got a text from Ian Stewart (who was at home watching the live results) telling me I had FTD and top score. It went downhill for me after that when the others had their turnlaughing.gif Great to know David Loomes' magic box of tricks was workingclap.gif George
Link to comment
Share on other sites

It was good fun to see all the bits working, just a shame my laptop's battery gave out.  I'll have to check up on why that happened as I was expecting it to have plenty of capacity. Then all we'll have to do is teach Pete how to find his way to the hill and how to land on top of it and w can have a real comptongue.gif See you all next year.party.gif David

Link to comment
Share on other sites

  • 1 month later...

reto.blumer said:

Hi Reto, how is the automated system coming along? I read in the Engineer magazine that Mercedes is planning to use a new system for detecting pedestrians using two camera's instead of one. Wonder if that would be a useful enhancement to your system? The two camera's work like your own eyes as they can detect depth as well. Link to article below. http://www.theengine.....cmpid=TE01 Cheers, Tom
Link to comment
Share on other sites

  • 9 months later...

Was out on the MTB today in the glorious November sunshine, gives me plenty of time to think on my 20 mile training loop up to the windmills and back. My thoughts were wondering whether it would be possible to develop a GPS F3F training aid, similar to the GPS Triangle racing format.

Would it be possible to use a GPS sensor in a model and telemetry that could be used to track its position on a virtual F3F course. I was thinking that you would be able to set the origin just before you launch as the middle point, and have two virtual bases 100m apart or 50m to your left and right of your origin. Then I guess you would need some clever software to time the 30 sec climb out and beep you off and on the course and the laps. Of course it probably wouldn't be practical to use in competition but might be a useful training aid. You would probably have to remove it for racing anyway with the intended rule changes on telemetry. Thoughts?

Tom

  • Like 1
Link to comment
Share on other sites

Tom, it would be great if it could be made to work. I think there might be an issue with accuracy though, specifically during the very high turn rates at each end of the course. GPSs available to us tend not to be that great in dynamic situations. Now if we could get our hands on an air-to-air missile GPS algorithm...

Simon

  • Like 1
Link to comment
Share on other sites

There's a bit of an obstacle to be overcome in finding any space inside a model that's barely big enough for the radio gear let alone anything else!

I have a fair bit of experience in building data loggers with GPS and the one I use in the timer can be set up for a variety of different dynamic environments ranging from stationary (only one satellite needed to maintain timing accuracy once initial lock acquired) to +/- 4g aerobatics, which would probably work for us in modest conditions.

Having run it on race cars and compared the 5Hz GPS output with data direct from wheel speed sensors, it is clear that there's some smoothing going on, so practicing with it a lot might teach you to fly a very consistent course that's slightly too short!

Since it would need to know not just where the centre is, but also which direction the course is laid out, you'd probably walk to one base, tell it that's base A and then walk along the edge until it beeped to let you know you'd walked 100m and set that as base B.

I've also plotted the output in real time on Google maps and I know that over a period of a few minutes, the indicated position wanders around by a few metres, so it'd never be good enough for anything other than some practice.

Might just be doable though.

  • Like 1
Link to comment
Share on other sites

Where does the wandering start?

(In Toms case its fighting windmills.)

would more receivers and an average reading improve the accuracy.

Just wondering.

Link to comment
Share on other sites

The wandering arises due to changing atmospheric conditions between the satellites and your receiver. If a cloud drifts between you and the satellite, it affects the time taken for the signal to reach you and your calculated position will appear to change.

The solution to this is DGPS or Differential GPS (http://en.wikipedia.org/wiki/Differential_GPS) which involves sticking a very clever piece of kit at a known position - in the centre of the course would be nice - and having it constantly monitor the errors in the satellite signals, then transmit corrections to your model. This approach is widely used in farming to control crop spraying equipment so that some crops don't get double dosed or missed altogether. It's a bit out of our league though.

There are global correction systems in place (WAAS and EGNOS are the well known ones - see the above linked article) but for the sort of accuracy we'd want and in real time, you'd need your own system up the hill with you. Oh and you'd have to know its location to an accuracy of 10cm or so for it to be any use.

David

Link to comment
Share on other sites

How inaccurate would the 'wanderings' be David, are we just talking a couple of metres? I think from a practice point of view that would be acceptable.

Link to comment
Share on other sites

It was a couple of years ago that I did the test, but we had the gear set up on a car at one of my pals' house with the reported position being shown on a google maps page. I remember being amazed that we could see the cross on the computer screen move if we pushed the car in and out of the garage. When we stopped though, the dot continued to move around in a random fashion over a distance of I'd guess 10 to 15 feet. The symbol definitely didn't jump around, it seemed to be moving at a very slow walking speed, taking a minute or two to move that sort of distance.

I'll see if I can repeat the experiment and record the results this time. While I'm at it I'll have a think about how to build such a thing. The biggest problem has to be getting it inside a modern F3F machine, then have it use as little power as possible. Obviously you need something in your hand to do the processing and buzzing - a blue tooth equipped smart phone would be nice.....

David

  • Like 1
Link to comment
Share on other sites

I'm with you that the hardest part will be fitting a new gubbins into a current generation fuselage, unless it goes behind the TE which would rule out most retrofits.

Why not just tie 50 m of string to the plane and if you break it you've gone too far??

:)

Link to comment
Share on other sites

Why not just tie 50 m of string to the plane and if you break it you've gone too far??

:)

Oh don't you just love it :D The more you think about it the better it gets :D

Link to comment
Share on other sites

Sounds a bit like the blind man going bungee jumping.

It's the only time you'll hear a Labrador scream, but he'll know he's near the bottom when the lead goes slack!!!

  • Like 1
Link to comment
Share on other sites

Why not just tie 50 m of string to the plane and if you break it you've gone too far??

:)

Fly by wire or

Control line F3f,

That's an interesting thought, stand down at the bottom of the hill (out of the wind and cold)

:D

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.