Espritmodel.com Telemetry Radio
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Old Jun 27, 2007, 03:16 PM
Marlon
Joined Sep 2004
100 Posts
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1 or 2 receivers/batteries **1:2,3 SCALE** ? What would y do to keep your $$ safe ?

The plane is a KA 6 CR from CNC and I'm looking for some advice on a bullet proof setup... just too much money and time involved on this project.
I will post pictures of the plane.... BTW looking for a scale pilot for it.
  • One receiver or Two receivers ?
  • NICD , NIMH, LIpo - 1r or 2 ? Power box ?
  • 2,4 ghz or 72mhz ?
  • on/off switch 1 or 2 ?
  • Any other improvements ?
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Old Jun 27, 2007, 03:25 PM
VNE ? I bite my thumb at thee
stinkyfive's Avatar
Shropshire, UK
Joined Jan 2005
501 Posts
2.4 Ghz, no question.



Emcotec DPSI
Lipo's
Vario with battery readout is probably the most reassuring though.

Ell.
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Old Jun 27, 2007, 04:13 PM
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Dorset, Southern England
Joined Dec 2006
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A very comprehensive article on the subject can be found here...

http://www.scalesoaring.co.uk/HintsT.../systems3a.htm

For me, the Common Mode Failure section convinced me to run two receivers and two batteries/switches on my biggest motorglider.
It's as the man says though, you can't beat a vario giving you a realtime voltage readout to still that beating heart...!
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Old Jun 27, 2007, 05:12 PM
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New York
Joined Feb 2002
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When was the last time an RX failed in one of your sailplanes? Probably about as often as your TX going out other than for battery. For my money: one RX, 2 battery packs and 2 switches. Fortunately the Ka-6 doesn't include a retract, otherwise you might consider a separate battery for it. And then of course there's the optional safety net extending completely over the field and surrounding counties.

These days I see more carnage due to carelessness and lack of attention to detail vs radio failure. Your mileage may vary.

Good luck,

Steve
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Old Jun 27, 2007, 09:48 PM
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pinolefm1's Avatar
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Quote:
Originally Posted by stinkyfive
2.4 Ghz, no question.


a fine system for non carbon fiber sailplanes.....
Not one I'd dump my 72mhz system and dozen or so 72mhz receivers I have for but if I were to start fresh and knew for certain I'd never fly carbon fiber planes again I'd seriously consider one

Steve
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Old Jun 28, 2007, 10:08 AM
Vintage wood is the best!
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Quote:
Originally Posted by pinolefm1
a fine system for non carbon fiber sailplanes.....
Not one I'd dump my 72mhz system and dozen or so 72mhz receivers I have for but if I were to start fresh and knew for certain I'd never fly carbon fiber planes again I'd seriously consider one

Steve

Agreed! That and the fact that it seems that everyone is jumping on the 2.4 Ghz bandwagon so 72 Mhz in a few years will be wide open!
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Old Jun 28, 2007, 12:34 PM
Look out! The lever!
bobthenuke's Avatar
United States, AZ, Peoria
Joined Feb 2005
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I use an EVO-12 Tx and for my larger sailplanes use MPX receivers. These have an auctioneered battery circuit to allow a primary and backup battery pack...a very nice setup IMO. As SteveR suggests, Rx and Tx failures are far and few between. Power is almost always the subsystem that will provide the greatest benefit by providing redundancy.

...bob
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Old Jun 29, 2007, 09:05 AM
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I now use two receivers/batteries on my large scale planes.

I recently had a crystal go bad on a relatively new JR 9ch PCM receiver. No prior crashes or abuse. Fortunately it failed when I turned the system back on and tested the controls just prior to launch. I had about a second of control then nothing. Flew two or three flights earlier that morning with the same plane without glitches or problems.

Don't know if you can run two receivers on 2.4 GHz but I would try especially if you are using standard receivers with crystals.

TommyT
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Old Jun 29, 2007, 11:00 AM
VNE ? I bite my thumb at thee
stinkyfive's Avatar
Shropshire, UK
Joined Jan 2005
501 Posts
35Mhz

I do agree about the rush to 2.4Ghz, I have too much invested in 35Mhz to make the swap currently, and the new rx's I buy (multiplex ipd synth & jr synth both pcm and ppm) appear to work so well that changing seems pointless (especially in an engine free model).

However, you did ask about 2.4Ghz, and it is without a doubt a far superior link to your model, JR/Graupner are also offering a telemetry unit in the near future, so even more peace of mind (or distraction)....

FWIW. Ell.
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Old Jun 29, 2007, 03:07 PM
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El Dorado Hills, California, U.S.A.
Joined Mar 2000
545 Posts
This may help you.

http://www.smart-fly.com/Products/Expander/expander.htm

I know somebody must make a device that electricaly swaps from one receiver to the other when the noise value(lack of signal, rx failure ,interference) increases, decreases, or lack of signal. We made a device that did this for testing the early 2GHZ receivers six years ago.

Use NMH or Nicad cells, stay away from Pen-Cell-Types, the failure rate is about five to ten times more than the stubby cell type. If you can make your own packs, use electric motor grade cells. Electric grade cells will be about 0.1v to 0.3v higher under load because of the lower internal resistance of the cell. The motor grade battery is more rugged cell and will last a very long time, I have some Sanyo RED(Very Rere) cells going on ten years-best cell evermade. Baned because high levels of Cadnium. Stay away from lithium polymer or Lithium ion, but the new Lithium nano-technology type cell is a very rugged and safe cell use. The best one to use is A123 or the Emoily's from Canada(I know I'm speaking French here, but on Ten Thousand USD glider only the cutting edge stuff counts). A123 are bullit proof these cells are used in the DEWALT 36v cordless tools. The Emoilys are used in the line of Milwakee 28v Power Tool line.

Hope this helps.

Martin

Hope this helps
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Old Jun 29, 2007, 08:08 PM
Vintage wood is the best!
SZD16's Avatar
In a house
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Quote:
Originally Posted by MAVA
Stay away from lithium polymer or Lithium ion,

What's the problem with these?

Smart-Fly sells Li-ion for the power expander.....if there no good....why do they suggest people use them?

http://www.smart-fly.com/Products/Fromeco/Fromeco.html
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Old Jun 29, 2007, 08:34 PM
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USA, TX, Dallas
Joined Jan 2007
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Quote:
Originally Posted by SZD16
Agreed! That and the fact that it seems that everyone is jumping on the 2.4 Ghz bandwagon so 72 Mhz in a few years will be wide open!

And cheaper even yet than it is now!
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Old Jun 30, 2007, 09:46 AM
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jooNorway's Avatar
Norway
Joined Jul 2005
796 Posts
As bobthenuke said: Buy yourself a good MXP-receiver with dual battery input. It requires 5S NiXX instead of 4 if you run dual batteries.

My advice: do NOT put switches on the batteri-circuits. If you want to avoid weak links in your setup, switches are the first thing to get rid off. In my planes there are not many with a switch onboard

If you use Picolario you always get warnings if the voltage drops onboard.

Keep it simple. Avoid junk-electronics. Add ferrites on the longest servoleads.

I can`t see any incrising of security by swapping to 2.4GHz...
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Old Jun 30, 2007, 07:07 PM
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Hi there mnluz my experience with large models has shown two lines of thought to work, the Kiss principle and the expensive one.
The first uses two gold JR switches between two 2200 mhmp nicad batteries going into two diffrent ports of your reciever and uses one JR PCM 10x receiver. This idea was offered in the old forum buy Peter Goldsmith a few years ago as being economical and reasonably idiot proof. The downside is if one battery fails it drags the other one down. So far in 26 years of flying I havn't ever had a JR gold switch fail and have been lucky with batteries!!

The second is to use a battery splitter from smartfly in the States, it monitors your battery voltage and switches to whitchever battery has the highest voltage. Additionally Smartfly also make some very nice switches that are designed to fail in a closed or still working circute. If your running high current draw such as in giant scale aerobatic models where you are expecting to pull more than 2 amps (your average JR receiver) then they also make 4 diffrent models of power expander that removes load from your receiver and can even allow you to gang up to 4 servos per channel and individually adjust them without using a powerbox!! The smartfly gear has been well and truely proven buy our power flying extreemos who fly Imac (big over power really makes me sick aerobatic guys)

As to dual receivers other than 2.4 gig radios Peter Goldsmith also found out the hard way that using 2 conventional receivers together is bad news as they interfeir with each other. Which now brings us to 2.4, at this early stage in 2.4 gigs savillion life (futaba has been selling it to the millitary for the past 12 years!!) I would be only using 2.4 with channel hopping capability (futaba has this JR is developing it for release next year) or at least broadcasting on 2 frequencies. But it is IDIOT PROOFE!!! as no idiot can switch on and shoot you down and you also can't do the same.
Regarding range, we recently tested a Spectrum 2.4 system in a 5 meter model and flew it to 3100 ft without a glitch.... it has also been competed with at a local comp incased in a carbon bodied glider and even in an all alluminium covered model again without a glitch! So at this point 2.4 looks wrather inviting and when they bring out a module and receiver (aka JR dx 12) for my pcm 10x with 10 channels, that is how I will be converting to for my big models.
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Old Jun 30, 2007, 09:01 PM
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Quote:
Originally Posted by Big Nuts 181
, we recently tested a Spectrum 2.4 system in a 5 meter model and flew it to 3100 ft without a glitch.... it has also been competed with at a local comp incased in a carbon bodied glider and even in an all alluminium covered model again without a glitch! So at this point 2.4 looks wrather inviting and when they bring out a module and receiver (aka JR dx 12) for my pcm 10x with 10 channels, that is how I will be converting to for my big models.
I'm just going to point out that no new system should be flown without extensive and thorough range checking and in the case of 2.4ghz in particular at as many different orientations as possible .The effort some are having to go through to try to get these 2,4ghz systems to work in some carbon fiber bodied planes is monumental ,well documented here on this website and not worth the trouble IMHO.It "seems" to have something to do with the density or thickness of the cf as some thinner walled planes appear to do OK where some thicker do not.Adding patches and whiskers as bandaids for poor reception does not appeal to me and the first time I see something like that on my home field I'm gonna hide in my truck until the flight is over one way or another

Steve
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