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Data logging and / or Telemetry ?

Old 12-29-2011, 01:50 AM
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solentlife
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Default Data logging and / or Telemetry ?

I've been using various Doppler speed programs to evaluate model performance ... but they all lack in terms of slower models and when wind noise / other sounds enter the recording.

I use FrSky radio modules and am thinking to change to Two-Way telemetry from the standard one-way in use now.

Main information I'm looking for is track / speed / altitude info.

I would think that a data logger recording info in flight is easiest way to go ... but probably more cost and heavier than telemetry. But it gives the possibility of PC download after for analysis.

I need advice / info on what people use and how to achieve it in lightest, smallest, most economic way .....

At present I am leaning towards FrSky two-way module, Rx, hub, GPS sensor, data display.

Does the GPS sensor and data display give tracked flight ? can it record to view later ?

???
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Old 12-29-2011, 02:42 AM
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Hey, solentlife. Back from I***?
Check this out.
http://eagletreesystems.com/Standalone/standalone.htm

They work either stand alone or with the Eagle Tree Systems data logger.

I'm picking up the altimeter on Friday for my son's science project - what is the optimum amount of water to provide the highest apogee for a water bottle rocket at a given pressure.
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Old 12-29-2011, 03:07 AM
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Originally Posted by earthsciteach View Post
Hey, solentlife. Back from I***?
Check this out.
http://eagletreesystems.com/Standalone/standalone.htm

They work either stand alone or with the Eagle Tree Systems data logger.

I'm picking up the altimeter on Friday for my son's science project - what is the optimum amount of water to provide the highest apogee for a water bottle rocket at a given pressure.
Hi earth .... skipped to Korea as well .... and just waiting to fly out home ...

Just ordered my 4S 960mAh 25C packs for the T45 ... 20mm x 10mm wheels to replace the larger ones supplied with the Stinger U/C ... so looking fwd to seeing postman ! How's your Mig doing now ? Carving uop the sky nice and fast now I reckon ?

Yep - I googled and got Eagle Tree ..... problem for me is cost ... have to find the most economic way to it..... and THAT little beauty looks neat ! I didn't see that one when I googled - I was taken to their main page with serious kit !

Did some calcs prior to testing the new packs when I get them ... will post up on another thread with test results later ... don't want to look an idiot quite yet !

Back to data - one of the main items I want is to be able to view the data after flight ... to aid in the quest for max speed out of the model. Doppler stuff is all well and good ... but prone to all that surrounding noise etc.
On-board data recorder is the way _ I know ... but all the low-cost stuff is too heavy / large. The real small stuff I want is way too high price for me ..

Open to suggestions !!

Last edited by solentlife; 12-29-2011 at 03:25 AM.
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Old 12-29-2011, 03:19 AM
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The Mig is great! I crashed it on landing a couple of weeks ago (dang wingtip grabbed the grass and it cartwheeled), rebuilt it and over-compensated for a tendency it had to roll to the right. Upon the next flight, at the school where I teach, It flew straight beautifully! Problem was, I couldn't get it to turn! I lost sight of it somewhere over my school, low to the roof, cut throttle and hoped for the best.

This was a Saturday, so the really useful parts of the building (such as the roof hatch) were not accessible. We (me and another teacher that I fly with) climbed trees surrounding the building to try to find it. No luck. Finally, I had the bright idea to throttle up on the TX to see if I could hear it. Sure enough!

We have 3 courtyards within our building with quite large trees growing in them (planted in 1965). We found a 14 foot step ladder in the gym (by kicking in the equipment room door-its common practice), climbed up on the roof, and there she hung. The Mig was about 10 feet above the roof line, perfectly intact!

I revisited my "adjustments" for that roll tendency and flew her on Christmas day. She flew like a dream! Gotta love it!
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Old 12-29-2011, 03:46 AM
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Love the story !!

Only mishap I had with a tree - actually a Privet hedge ..... open field, mate of mine hand launching my big biplane ... silly b****r threw it straight into the bloody hedge !! That was the end of a long love affair with that model ... she'd survived more than 6 years till then with only a few scratches.

Same guy was my Pylon race launcher .... and as you know - with that when the flag drops - HE bungs it whether you're ready or not ! Yep ... I was distracted for a few secs just as flag dropped - he launched like a javelin ... for me to fight to keep it from burying itself in the ground ! I reckon that took 5 years out of my life.

back to EDF ... I flew the T45 with the /C before I left for assignment ... and it was OK. Speed appeared to be less, maybe because I was expecting it ... never video'd as it was a spur of the moment flight on rough ground. The balance was more fwd ... but made no difference to trim. Its strange this trim / CoG with the T45 ... going frrom a 65 gram pack up to a 124 gram pack in nose ... only thing you notice is less speed on the smaller pack, but trim is near same. Even though the CoG moves about 20mm.
I wonder if the ducts allied to wingform have something to do with it ?
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Old 12-29-2011, 04:03 AM
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Well, while you are waiting in various airports for flights to God only knows where...
Check out this guys website:
http://donsrc.com/cart/index.php?act...d&productId=97
He doesn't have a video of the T-45 with this setup, but here's the 50 mm Mig:
[media]http://www.youtube.com/watch?v=-bgjjP4U6n0&list=UUQa50msKiIfGF9Lzylzf4hw&index=5&f eature=plcp[/media]

I'm salivating!
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Old 12-29-2011, 07:03 AM
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just putting last bits in bag ... then driver arrives to take me to airport ....

That is one wicked Mig !! Love it ......

just Dopplered his video .... results :
  • 0:13 - 34.0 MPH
  • 0:27 - 88.4 MPH
  • 0:29 - 53.4 MPH
  • 0:55 - 94.6 MPH
  • 1:09 - 41.7 MPH
  • 1:23 - 94.0 MPH
  • 1:25 - 28.3 MPH
  • 2:56 - 96.3 MPH
  • 2:59 - 42.8 MPH
  • 3:10 - 75.3 MPH
  • 3:15 - 66.1 MPH
  • 4:22 - 94.2 MPH
  • 4:36 - 23.1 MPH
  • 5:20 - 81.0 MPH
First numbers are the time slot in the video ... then the speed in MPH ... so 96.3mph max ... not bad !!

I reckon to keep with stock DF unit till it basically gives out. I will then swap out for a 6 - 7 blade 51mm unit ... with 5500 - 6000KV motor with 4S up it's chuff !

Yes I know it's gonna be a high amp draw and likely to fail in short time - but the push for speed is what's diving me !!

Last edited by solentlife; 12-29-2011 at 07:21 AM. Reason: insert doppler readings
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Old 01-05-2012, 09:47 AM
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Like the Dons set-up- but it's a package deal in USA as I see it ...

So I'll stick with my own DIY route. Trouble finding a suitable 20mm mount 6000KV ... so opted for the Turnigy 5000KV unit. That should be a direct drop in to the T45 stock fan.

Specs indicate stock ESC should work with it. So first runs with stock fan / ESC / 3S and new 5000KV - see what happens.

I have a higher rated ESC on way ready for the 4S into the 5000KV ... I expect to have more heat production and this may offset a lot of the apparent benefit of increased motor KV etc.

HK is slow at this time of year !!
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