2,4Ghz

[Jocke]

Anyone using the 2,4Ghz radio system for large electric planes/setups?

[sun.flyer]

Yeap, been flying with a AR7000 in my beta 3DHS 85" Extra 260 with great success.

Tim

[Jocke]

Nice to hear, you feel its better now with 2,4ghz in terms of interference and glitching from powersystem?

[megawatt]

I am using Spektrum DX-7 in my 1/4 scale super cub.Have been flying DX-6/DX-7 for over 2 years.NEVER had a glitch!It tends to add a new level of comfort when flying, by removing the fear that someone may accidently decide to share your frequency.(Way bad with the big birds! :eek: )

Jeff

[sun.flyer]

Nice to hear, you feel its better now with 2,4ghz in terms of interference and glitching from powersystem?

I would say this is still to be seen. This past weekend I say a guy loose his IMAA legal plane because he was using a 4.8 volt system and his rx went into reboot while he was at 50ft off the deck. Total loss of aircraft, was able to salvage equipment however.

I think that Horizon has identified this issue and is now offering diodes to put on your receiver to prevent reboot issue. I definately feel that 2.4ghz is the new 72mhz and you will continue to see manufactures marketing this through there line of radio systems.

Tim

[cooper998]

My Sig Rascal 110 originally used my 9 channel Futaba 9Cap and matching receiver and I just recently switched to a Futaba Fasst system due to glitching experienced during landings from the far end of our field. So far the 2.4 system has worked flawlessly and no more glitching was experienced. I was original hesitant to experiment with the 2.4 system in the Rascal but after flying it in a smaller plane I felt comfortable enough to try it in the Rascal.
One word of caution, make sure your receiver battery is large enough to supply enough voltage to the receiver or it will reset(not sure if it would happen with the Futaba). I use a 2700mah receiver battery to power 5 high torque servos and monitor the voltage before each flight. I have witnessed a couple of flyers lose their plane due to small receiver packs being used.

cooper998

[BobMcClure]

Jocke - A lot of giant sized models fly with the new Spread Spectrum radios. Here's an item from the Joe Nall fun fly.
"The Spektrum people from Horizon thought that the ultimate expression of confidence in the new 2.4Ghz system would be flying it in an Ultra Bandit with JetCat P-180 power. It worked perfectly at the hands of Chris Huhn, as did dozens of other Spektrums at this, the biggest model flying event in the world." Joe Nall (http://www.bvmjets.com/HotShots/nall07/joe_nall07.html )

[Jocke]

So there are no downsides ;) thats nice, one can start thinking big and then bigger electric conversions with not as much worying of glitching from powersystem.

[GordonTarling]

Jocke - if you believe all you read in forums, there ARE downsides. However, I'm sure a lot of the problems being reported are due to people not taking due care with installation and instructions! I don't know what radio you're using, but I've just ordered an Xtremelink module for my Graupner MC-24 and a 10 channel receiver, so can report on that when it arrives if it will help.

[Jocke]

That would help, all info i can get is good, im now using Futaba FF9.

[Andrew McGregor]

There's really only two things to worry about.

1) Make absolutely sure you have enough power for all the servos and the RX, because all the 2.4GHz systems behave badly on power dropouts. What exactly happens and how bad it can be depends on the system, but they are all quite capable of crashing a model on a power dropout. 4.8V nickel packs are often undersized, and have little margin. 6V nickel, 2S A123 or any switchmode lithium BEC or regulator system is the ticket here.

2) Range check at all orientations, and if it doesn't check, don't fly. Especially check the orientations shadowed by motor, packs, wing spars, and the tail group. Landing gear as well if there's a lot of metal in that, and if you have retracts, check both gear up and gear down. The options for dealing with a failed range check basically come down to moving antennas out of shadows. The Spektrum AR9000 is useful here because you can get the two sattelite receivers 2m apart with extension cables... there are not many airframes you can't get at least 1 of 3 antennas with a full meter of separation out of the shadows.

If you have a mostly carbon-fiber model, you need to be extremely careful with the range checking, and be prepared for it to be impossible to range-check without significant effort involving external antennas... fortunately, that problem mostly applies to gliders.

[ekotil]

Anyone using the 2,4Ghz radio system for large electric planes/setups?
Been flying my 80" Lanier Stinger with Axi 5330/18 on 2-5s2p packs with total confidence and trouble free performance. Prior to my conversion to the Spektrum 7000 I would routinely be glitched nearly every flight. After almost piling it up because of a low level(altitude) glitch I took the plunge and switched 29 electric models to Spektrum. 2.4 is the best thing to happen to R/C ever! I had never before experienced this level of total trouble free performance. I rely on mostly Jeti ESC's with BEC although on my bigger stuff( over 65") I am using a UBEC. When the motor starts to lose it's edge it gives me 2-3 minutes to land and enough power to idle back into the pit area. The fuel guys hate it since they usually make dead stick approaches and sometimes they land. Other times they make semi-controlled crashes. More of them are converting over to electric and 2.4 grudgingly every month.

[feathermerchant]

I am flying an 85" proto 3DHS Katana (see my blog) on 2.4G. I am using 12S but only 4S powers the 6V UBEC. The UBEC is more efficeint in this range and with a 6V output I feel safer. I think the larger, more powerful electric setups have more RF interference to overcome. 2.4G seems to be high enough freq that it is not bothered.

[Pheasant]

The diodes that are available for Spektrum are intended for surface use only.

Just as there are setup requirements for the correct operation of 72mhz equipment, there are for spread spectrum. One very important one, as others have noted, is that the radio power system is capable of delivering sufficient voltage and current during all expected flight conditions. This will obviously be different from a Cub to a 3D Extra. A 4.8V system is fine for Spektrum providing it is correctly sized.

I think 2.4 is a pretty big leap over 72mhz, unquestionably the future of radio control.

CG.


I would say this is still to be seen. This past weekend I say a guy loose his IMAA legal plane because he was using a 4.8 volt system and his rx went into reboot while he was at 50ft off the deck. Total loss of aircraft, was able to salvage equipment however.

I think that Horizon has identified this issue and is now offering diodes to put on your receiver to prevent reboot issue. I definately feel that 2.4ghz is the new 72mhz and you will continue to see manufactures marketing this through there line of radio systems.

Tim

[GordonTarling]

Jocke - Just thought I'd give you a short update on my Extremelink 2.4 gHz setup. It arrived in good time, but I was rather miffed to find that the Tx module wasn't moulded the same as any other JR Tx module and thus wouldn't plug straight into my MC24 transmitter. I was even more miffed when an email I sent to Extreme Systems about the problem didn't receive an answer! I suppose I could have sent the whole lot back there and then, but I wanted to try it out, so I hit the Internet and did some research!

I found a fairly simple way to fit the 2.4 module inside my Tx and still retain the ability to refit the 35mHz module when I needed to. I can provide details if you need me to!

With that problem sorted out, I tried it on the bench and had a bit of a problem getting the receiver bound to the transmitter, but I persevered and got it all to work eventually. It seemed OK on the bench, so then had to decide which model to fit it into for tests. There really was no choice, because I was experiencing glitching problems with my Logo 10 helicopter and the 2.4 setup seemed like it offered a simple solution! Easily installed in the model, range checks exceeded manufacturer's recommendations by a large amount in all the orientations I could achieve, so it was time to get airborne!

I have to emphasise here that I'm only a novice heli flyer and thus am not pushing this system to anywhere near its limits of range or orientations, but have found that it just does what it's supposed to do. I've experienced no glitches or lockouts at all in about 6 flights that I've had so far, so I'm fairly happy with it.

My only very slight problem so far has been that when powering up, the receiver doesn't always seem to initialise properly and I don't get the solid green LED that shows a good link with the Tx. I'm guessing that this is because my heli is using a separate BEC and I don't have a switch on the power to the receiver, so am probably not always getting a clean first-time connection when I plug the battery in. Usually, a quick reconnect will do the trick, though there has been a couple of occasions when two or three reconnects have been necessary. The Extreme receivers have a very short boot-up time in order to help eliminate power dropout problems when airborne, so I suspect that what I'm seeing is a direct result of this. I'm going to try temporarily adding a switch in the power line to the receiver to see if this will fix the problem.

I'm very happy with the way the system works, so am now trying to decide which of my models (fixed wing) I should try it in next. I'm leaning toward my LT-25 AP ship at the moment, purely because it gets flown at distances from me that none of my other models do and I'm loathe to trust it 100% in my 1/4 scale Tiger Moth just yet!

One last comment - when flying with others, it feels very odd just going to fly without bothering about any sort of frequency control or checking and I'll have to watch that I don't get into bad habits when I go back to flying 35mHz!

[Andrew McGregor]

The diodes that are available for Spektrum are intended for surface use only.


They're capacitors, actually. And while they're only intended for surface, they won't actually hurt in a plane... it's just they won't help enough to matter either, so they're a waste of weight. Better to uprate batteries or BEC.

[flypaper 2]

I've been flying a 1/4 scale Corby Starlet for quite a while, as well as other planes, with the Spektrum with no problems what so ever. The 1100 ma. 4.8 V pack that came with the radio works fine. I use an ESV before every flight and never let the pack get below 5.2 volts. I get four flights out of a charge.

[Pheasant]

Excellent to hear.

Is that a plans built Corby? I had one built from Tapsfield plans (38%), was a great flying airplane.



I've been flying a 1/4 scale Corby Starlet for quite a while, as well as other planes, with the Spektrum with no problems what so ever. The 1100 ma. 4.8 V pack that came with the radio works fine. I use an ESV before every flight and never let the pack get below 5.2 volts. I get four flights out of a charge.

[Jocke]

As it seems now i think i will try FUTABA 2,4ghz, hoping for a revolution, no more problem.

[flypaper 2]

Not sure whose plans for the Corby. I bought it from a fellow club member about 15 yrs ago. Like me, it's getting a little rough around the edges but keeps on truckin. :D At around 80 in span, it flies like a great big foamy. :p

[Pheasant]

Might be the same, mine was about 82". Started with an Enya R1.20 then changed to a Saito 1.50. Flew great with both motors.


Not sure whose plans for the Corby. I bought it from a fellow club member about 15 yrs ago. Like me, it's getting a little rough around the edges but keeps on truckin. :D At around 80 in span, it flies like a great big foamy. :p

[Pheasant]

Any reason not to try Spektrum? I prefer it to the Futaba as it's proven, available, faster, and has multiple antenna options.

The very large majority of motor generated RF occurs far below the 2.4ghz band so those probably are truly gone.



As it seems now i think i will try FUTABA 2,4ghz, hoping for a revolution, no more problem.

[desert_flyer]

I use two 6V VHVBECs in series on my big YAK - these are connected from the main 12S pack. They are rated for up to 15S. No problems so far - I just check that both BEC power lights show up before each flight. The rx is the AR7000 and I mount the remote antenna under the fuse. The system is very responsive - lots of expo is needed.

[Erik v. Schaik]

There's really only two things to worry about.

1) Make absolutely sure you have enough power for all the servos and the RX, because all the 2.4GHz systems behave badly on power dropouts. What exactly happens and how bad it can be depends on the system, but they are all quite capable of crashing a model on a power dropout. 4.8V nickel packs are often undersized, and have little margin. 6V nickel, 2S A123 or any switchmode lithium BEC or regulator system is the ticket here.

2) Range check at all orientations, and if it doesn't check, don't fly. Especially check the orientations shadowed by motor, packs, wing spars, and the tail group. Landing gear as well if there's a lot of metal in that, and if you have retracts, check both gear up and gear down. The options for dealing with a failed range check basically come down to moving antennas out of shadows. The Spektrum AR9000 is useful here because you can get the two sattelite receivers 2m apart with extension cables... there are not many airframes you can't get at least 1 of 3 antennas with a full meter of separation out of the shadows.

If you have a mostly carbon-fiber model, you need to be extremely careful with the range checking, and be prepared for it to be impossible to range-check without significant effort involving external antennas... fortunately, that problem mostly applies to gliders.

I have found an other downside to my just prushased Spektrum Dx7 Tx:
No throttle timer!! :mad: Only a normal timer or count down.

I am trying to get the most high efficiency of my 13s2p A123 setup (in my case with 2x90mm edf=3kW :rolleyes: ) The drive setup has 94% motor efficiency and now I have to reduce flight times to 3-4 minutes to be sure not to run my pack empty and crash!

Currently I am in search for an Ah telemetry system which is capeable of warning me with an acoustic signal when a preset Ah has been exeeded. With my 4s and 6s pack in my smaller planes I do run them down 2200MaH which is 95.6% empty :D THAT'S EFFICIENCY!


I'm reading this at this moment, I do hope some can help me here.
http://www.eagletreesystems.com/MicroPower/micro.htm


Thanks in advance, Erik

[Andrew McGregor]

On my helis, I use a simple voltage alarm that turns on a bunch of very bright LEDs when the voltage gets below a preset level. It nails 80% of the (lipo) pack capacity every time, which is exactly what I'm aiming for.

[flypaper 2]

Sounds like a great idea Andrew. Where does one come by one of these devices.? I'm all for the KISS principle. :D

[Andrew McGregor]

I got mine from www.rchelis.co.nz, or you could PM EFlierNZ on here, who makes them. He can do custom LED configurations to suit the aircraft.

[Erik v. Schaik]

On my helis, I use a simple voltage alarm that turns on a bunch of very bright LEDs when the voltage gets below a preset level. It nails 80% of the (lipo) pack capacity every time, which is exactly what I'm aiming for.

One cannot do this with A123. The voltage curve is too shallow for this. I would like an warning system when a preset consumption of mAh is reached.

much safer this way too!

[jonnyjetprop]

Gordon,

A good flying buddy bought one of Jim Drew's systems. While we had some problems at first, we were able to work them out.

The receiver is sensitive to the distance between Tx and RX on power up. Small models were not a problem, larger planes were. I was holding the model and turning on the switch while he stood with the transmitter. Several times he was just a bit too far away for the receiver to lock on.

Hope it helps.

John

[Erik v. Schaik]

The Dx7 is only available in mode2 (throttle+rudder on left rocker and aileron+elevator on right rocker) the rockers can be swapped in the Tx, but the trimming does not. I am lucky flying mode2 and have no problems with is, but all other guys at our field will be P#ssed :p . Nothing of this is mentioned in the poor manual. Even the voltage range of the Rx is only mentioned briefly (not under 4.7V) but the maximum limit is not mentioned. I guess 6V is no problem :confused:

[Heather]

The Dx7 is only available in mode2

In New Zealand we can buy the DX7 in either mode 1 or 2, but it cannot be changed from one to the other, which I agree... sucks.

Heather

[Pheasant]

I'm in the US and fly a Mode 1 DX7, as does my friend. Horizon Hobby is able to do the conversion.



The Dx7 is only available in mode2 (throttle+rudder on left rocker and aileron+elevator on right rocker) the rockers can be swapped in the Tx, but the trimming does not. I am lucky flying mode2 and have no problems with is, but all other guys at our field will be P#ssed :p . Nothing of this is mentioned in the poor manual. Even the voltage range of the Rx is only mentioned briefly (not under 4.7V) but the maximum limit is not mentioned. I guess 6V is no problem :confused:

[feathermerchant]

Erik - I have several planes with 6V BEC's and Spektrum receivers with no problems.

[Erik v. Schaik]

found it:
http://www.spektrumrc.com/Products/TechnicalSpecs.aspx?ProdID=SPM6070

An other question:
For High powered edf systems (very tight in the plane, more as in prop powered planes) Would the Ar9000 with 3 receivers a better choice? The Dx7 has only 7 channels and what is the use of chanel 8 and 9? best I can think off is connecting the two UBEC connectors on them :confused: The AR9000 has dsm2 technology as like the Dx7...

[turbonut]

The Dx7 is only available in mode2 (throttle+rudder on left rocker and aileron+elevator on right rocker) the rockers can be swapped in the Tx, but the trimming does not. I am lucky flying mode2 and have no problems with is, but all other guys at our field will be P#ssed :p . Nothing of this is mentioned in the poor manual. Even the voltage range of the Rx is only mentioned briefly (not under 4.7V) but the maximum limit is not mentioned. I guess 6V is no problem :confused:

Horizon shows the dx 7 also has mode 1 available on the dealer web site!
There is also a dx9 in the works and the Jr 93032.4 can use the ar9000 recievers as also any that use the module on the back to convert to 2.4

[feathermerchant]

You can also buy an analyzer for the 9000 that logs the activity of each receiver, dropped frames, etc.