What you can do with the GRT EFIS....

[mgomez]

Originally Posted by penguin

Paul,

I'm guessing that it is much more difficult to measure stick force or elevator per g, do you have any such data?
Pete

There are CAFE Foundation reports on the RV-6 and RV-8A which include stick force per g. I don't remember if they included elevator deflection per g. They're free on the CAFE web site, www.cafefoundation.org

Cheers,
Martin

[Davepar]

Not sure how this relates to Kevin's work, but somebody has posted data logging software on Dynon's support forum:
http://dynonavionics.com/cgi-bin/yab...num=1131123528

It's very cool to have these tools available for post-flight analysis.

Dave

[Kevin Horton]

Originally Posted by Ironflight

Pete, I'll have to digest some of your questions when I have a little more time. The period of the Phugoid is actually about 30 seconds for this case, and so far I have found little variationin that with CG. It does appear to be more damped at foward CG, as expected. This was just a quick example of what we can do!

Paul

In theory, the period of the phugoid should be proportional to the TAS, if I recall correctly from my TPS classes (too many years ago). Two different aircraft types should have the same phugoid period, if the tests are done at the same TAS. In the type certificated world, it is considered acceptable for the phugoid to be very lightly damped, even slightly divergent, as the period is so long that the workload to control it is normally very low.

[Kevin Horton]

Originally Posted by Davepar

Not sure how this relates to Kevin's work, but somebody has posted data logging software on Dynon's support forum:
http://dynonavionics.com/cgi-bin/yab...num=1131123528

Dave

That software, the Waiters Flight Data Recorder looks quite interesting, but it has no relation to the stuff Mike and I are working on. It is a Windows-only solution. Our scripts use perl, which is freely available on Windows, Linux and OS X (which is what I'm using).

I'll post in this forum whenever Mike's scripts are ready for release. I suspect we are a few months away from that though. I've stopped development of my original script, because Mike's looked so good. But there is at least one major bug to exorcise, and many small features to add, before it is releasable. And Mike has other things going on, so it is often many weeks between updates.

Edit - I must be getting old, as I forgot to mention that my data logging scripts (Dynon D10A and GRT EIS 4000) are available on my web site. They are very crude
Perl scripts, but they work. I've tested them on OS X 10.4.2, but they will almost certainly work with Linux, and I did have an earlier version working with Active State Perl on Windows and OS X 10.3. The current version hasn't been tested on Windows. Get the scripts here.

[zkvii]

My main form of contact for this will be via the GRT Yahoo List, please see / use that for upto date info / contact.


Hi all,

As has been mentioned I've been quietly working on a utility to extract information for the .LOG files that can be recorded on a PFD.

Well after some help with specs from GRT (thanks Jeff / Greg) and some testing by Paul Dye (ironflight) it is as ready as it is going to be for a public release.

Please bear in mind this is un-supported by GRT and will only get limited support from me, any data errors I'm very keen to get flagged but otherwise as I don't have a flying plane (and I'm still in the waiting list for a GRT dual PFD system), I must focus on other things as a priority ;-)

Some notes / things to be aware of:

• This is a commandline utility - no windows use interface so you will need to use a 'DOS' window and type a command line.
  
• ALL values are currently un-validated - I've implemented the specs as best I know and the numbers 'look' right, but without careful testing with known cases I can't be SURE. If you can validate / test / confirm / prove one way or the other I (we all) would like to know.
  
• The analog values require calibration constants - these are specific to a PFD (ie. therefore playing a .LOG on a different PFD to the one it was recorded on will provide a SLIGHTLY different representation). Currently the constants are hardcoded - but visible in the XML output. I may be able to refine these to 'theoretical values' given some time and hopefully long term we will be able to read the constants dynamically as needed.
  
• GPS decode is only working for 'aviation format'
  
• I'm unsure of some of the units - eg. degrees C / degrees F, knots / mph, litres / gallons and it will vary depending on your setup - just be careful and validate some known points before you start 'trusting' the data.
  
• The XSLT sheet is available via my website - this provides an easy way of presenting the data in a neat manor and also providing a prompt for new versions when they are released.
  
• No error checking is done on the inbound file stream - it may be that strange results will get generated if something starts going awol.
  
• Beware of the XML file sizes - they can get VERY big, very quickly. The non-summary functionality is there, but you probably don't want it. Likewise the verbose option adds detail to the XML but little value for normal use. The XML files do compress well however.

Once things settle down a little, I would like to methodically work through each of the parameters and get positive confirmation of readings with different people. This will need a combined effort as it depends on what configuration / connections different installations have and time / effort to coordinate the results.

The web page:
http://www.rvproject.gen.nz/grt/

Example output:
http://www.rvproject.gen.nz/grt/TESTDATA.xml

I suspect this is going to generate some interest / workload - please bare with me if things are taking a bit of time.

Regards,

Carl
--
ZK-VII - RV 7A QB - fuse / engine
Cromwell, New Zealand
http://www.rvproject.gen.nz/

[Ironflight]

.....and now that Carl has released the beast into the wild, I want to say again just how much of an incredible service he is providing to those folks with the GRT EFIS!

He has been working on this utility for just a couple of weeks, and had the first version running in only a couple days after I posed a question on the GRT Yahoo group. They must have really long days there in New Zealand, becasue he seemed to be working on it at just about every moment of our day and night.

It does take a little command-line-savvy to run, but once you figure that out, you can convert files pretty fast. (My modern-computer-savvy Coop Student Task Force had more trouble with DOS than I did - I guess that means I am gettign really old....).

All of the AHRS/EIS data appears to be in common units - Knots, feet, degrees F, etc. A few things like Manifold Pressure are uncalibrated, but since you know the scale factor and bias values for your specific MAP sensor, it is easy to compute. Volts are in volts. I have found little need for the EFIS analog paramters yet.

This is the "Killer App" for the GRT EFIS.....


Paul

[Scott Will]

Carl,

Thank you, thank you, thank you for your efforts. Way cool. I contacted GRT a month ago asking for the data definitions but it's been a month and I just bugged them again. I'm a aircraft performance engineer for a major airline and I write a lot of code at work so you can be sure that I was interested in doing what you're doing.

I know there's a lot of talented RV people out there - maybe we all could help out or figure out what we really want to do.

We use APM/ETM (aircraft performance monitoring & engine trend monitoring) here at work to diagnose problems before they arise (hopefully). I can try to incorporate some of that methodology.

I sort of want to get the data log real time so I can either store it to a laptop/PDA and do other things with it.

Just wanted to let ya know that there are others out there...

Thanks again,
Scott