Hey there fellas,

I have been a member of FGs for a little while now, and this is the first time I am posting anything. So from YorkPA, hey there ya'll!!

I am hoping that someone might be able to help me with understanding something. I have been using the Spektrum Aircraft Module in my JR 10X Air transmitter since about June 2007 with out any major issues until now. I have experienced two things in that time and the second one is not good at all.

First thing, I began to fly my first gas plane this year a 35% Aeroworks Yak-54 and I used my JR 10X radio with a Synthesized module and receiver with out any major issues. The only thing I did see from time to time was minor interference while flying but never anything to be concerned about. Well the opportunity presented itself for me to upgrade to the Spektrum module and receiver and so I did so, mostly because I often worried about being shoot down and the added benefit of not needing to visit the channel board at the field. I had flown my Yak for about 10 or more flights on the Spektrum, when one morning I flipped on the transmitter and then my receiver and all the control surfaces began to twitch and then stopped. A few seconds later they all twitched again and now I was concerned and I backed off of flying for the moment while I tried to figure out what was going on. Through my inspection I found that the antenna connector on my transmitter had come loose but not disconnected. I turned my 10X back on and then the receiver, I then touched the antenna connection on the back of the 10X and noticed that each time I did do the control surfaces would twitch, so I tightened up all the nuts on the antenna and I had not had an issue since.

Until last week!!! Arrrggg!!! I had bought a fully assembled Hangar-9 Extra 260 from a fellow pilot about two months ago and then installed the Spektrum AR7000 receiver that I had been using in my H9 Showtime. I didn't experience an issue with the radio or receiver in the Extra 260 the entire time I had it, until last week. I had improved my 3D flying this year and I had even dialed in the Extra 260 to fly a very good Harrier and I finally was holding a very solid Hover and was very happy with the set-up. Then it happened, I had heard and read about other pilots being locked out of any control from the transmitter to the receiver with their Spektrum units but I didn't think it would happen to me.

I had just pulled the receiver and ignition batteries off the chargers and my 10X off of the charger as well and even checked the batteries in the Extra with my volt meter and they were fully charged. The screen on my 10X read 12.6 volts so I knew all the batteries were fully charged and ready to go. I had been practicing my harriers again and I went into a hover for a few seconds and then powered up the throttle to pull out when I lost all control of the Extra. I immediately felt the radio had no connectivity with the plane and all I could do was watch. The plane stayed at full throttle (I am positive that I had set the fail-safe to low throttle) and I could not figure out why, and the Extra leveled out to the belly and then took a hard right turn and went towards the ground. It hit the landing gear very hard and it took off again (I don't know how), and went straight up and did a very bad rendition of a hammer-head and went straight back down into a set of small trees and bushes. Needless to say the Extra was smashed up pretty good and is not worth the effort to rebuild.

The thing that gets me, is that I understand the issue with Spektrum and the low voltage cut-off and the receiver rebooting, but I didn’t have that in this situation because I am positive that all the batteries were fully charged. The other thing that gets me is that I thought that Spektrum was impervious to interference, but I am not sure if that is what it was either so I am at a loss for what possibly could have happened. I also flipped my 10X over and checked the connection of the antenna with the TX module and it was still very tight, so I don’t suspect that either. I did notice once I retrieved the plane from the trees that the remote antenna was unplugged, but I am not sure if that happened in the crash or if it somehow came loose in flight, and I am positive it was connected when I attached the canopy to the plane. I don’t know if when the remote receiver is disconnected if it will cause a lock out like that or not, but I suspect that I still should have had some control over the plane if it did. I know that I have said a lot here and I thank you if you were patient enough to read all of this, but if you or anyone would have some insight or experience that you can share with me I would greatly appreciate it.

Well if you are sure you set your failsafe to idle then it likely wasn't a loss of signal. Have you tested your failsafe before? Turn off your tx and see if it goes to idle now. Also, if you do a range check, get out of range and push the power down button (bind button on the back of the tx). Have someone watch your throttle servo when the system goes into failsafe and verify it works. Now you will see what happens if the signal is lost. If the plane didn't go to idle in your crash, then it was likely not a loss of signal. Then you need to look for other causes.

Your Tx read 12.6 volts? Is it a 9.6 volt pack? If so, mine only reads a little over 11 volts on a full charge. Just curious. Also, and most importantly, what packs are you runnung? 4 or 5 cell? Dual packs? What Mah? How many connectors going into the receiver? What technology? If Li-ion are you using regulators and which variety? What size H9 plane is this? They make a 27 and 35% Extra 260. How many serovs? Digital?

Lots of styff to consider here. Once you can rule out all of the above as causes, then you may need to send the rx to Horizon to be checked out.

yes we need info on what you had in da plane fo power to the radio

I have had the same experience with a non 2.4 set up. I had failsafe set to kill the throttle and a Rcats kill switch that also should have killed the engine. Well after the crash i took all the part back to the house and tested to find out what situaion could cause a plane set up the way mine was and induce the problem i had no failsafe out of my pcm jr rx and no cut off of the rc kill switch.

The kill switch with no power will not let the ign send a spark the rx would go into failsafe if i lost signal. So after some testing i found that when the batteries got low enough (about 3.7 volts) the rx doesnt go into failsafe because it see's a signal but the servos would not respond (To low a voltage )and the kill switch allowed the ign to send electricty so the prob was a low battery or a bad battery This was all on my old version wild hare 50cc extra.

this kind of thing can happen to 2.4 rx's to so theres one more thing to look for.

Just a thought, since you were hovering close in, was the antenna pointed directly at the plane? I heard this could create a problem 2.4 or not.
I always point my antenna on my 2.4 straight up 90 degrees from the radio.

what kind of battery are you running in the transmitter? 12.6 volts sounds like a li-ion battey voltage. If so, that could very well be the problem. The Spektrum instructions INSIST (at least in my instruction booklet) on NOT running lithium in the tx, as the voltage is too high and will overheat and damage the tiny diodes, regs, etc. in the module/transmission board.
Beyond that, are you 100% positive that you set the failsafe to low throttle, as in you fired the engine up with tx/rx on and then turned the tx off to verify that the engine shut down? I say it this way, because if you found you had to reverse the throttle servo during radio setup, then it would actually have gone to full throttle in a failsafe situation if you did not re-bind after reversing the servo.
It is still possible that you lost voltage to the receiver - a fully charged battery means nothing if the switch/wiring/plugs in between fail.
Also, you DO NOT lose your rx link if the remote rx comes unplugged, but you will lose range.

Originally Posted by bodywerks

It is still possible that you lost voltage to the receiver - a fully charged battery means nothing if the switch/wiring/plugs in between fail.
Also, you DO NOT lose your rx link if the remote rx comes unplugged, but you will lose range.

I agree with with "bodywerks", there are many reasons for loss of control. Lost of the radio link is one of the less likely causes based on many years of experience.
Connectors are a more common problem. As an example I was test flying another fliers airplane today and was doing a lot of rolls and snap rolls. Ailerons became intermitten when rolling. I quickley landed and what we found was that the weight of a "Y" harness being used for the ailerons was causing the plug to come out of the receiver. A couple more snap rolls and it would have complely pulled out of the receiver. No, this may not be the cause of your crash but it does show what can happen with the connectors used in our models.

Originally Posted by bodywerks

what kind of battery are you running in the transmitter? 12.6 volts sounds like a li-ion battey voltage. If so, that could very well be the problem. The Spektrum instructions INSIST (at least in my instruction booklet) on NOT running lithium in the tx, as the voltage is too high and will overheat and damage the tiny diodes, regs, etc. in the module/transmission board.
Beyond that, are you 100% positive that you set the failsafe to low throttle, as in you fired the engine up with tx/rx on and then turned the tx off to verify that the engine shut down? I say it this way, because if you found you had to reverse the throttle servo during radio setup, then it would actually have gone to full throttle in a failsafe situation if you did not re-bind after reversing the servo.
It is still possible that you lost voltage to the receiver - a fully charged battery means nothing if the switch/wiring/plugs in between fail.
Also, you DO NOT lose your rx link if the remote rx comes unplugged, but you will lose range.

My manual for the airmod upgrade does not say anything about what type of Tx battery I can use.
I am using the duralite Li-ion pack in my 10x and spektrum, it does settle below 12 volts very quickly though.........

My question is............you had radio interference with 72mhz.....you switched to 2.4 thinking it would go away (and for the shootdown) Then when you had issues on 2.4 you just tightened some screws?

IMHO you should have sent the radio in for a checkup. Along with the spektrum gear.

Lastly.......which version of Spektrum was it? The new version doesn't require a screw to hold the antenna in place....it pops over an installed screwed in piece of plastic. It also has the new software that disables over 100% throw effecting the next channel in line. And did you glue down the capacitor like it says on Spektrums site? How many antennas and where were they in relation to the plane?

Lots of questions to answer

Benny, I copied and pasted this from my 9303 manual"
5. Q: Can I use a 3-cell Li-Po pack in my transmitter
A: No. All current JR and Spektrum transmitters are
designed to operate using a 9.6-volt transmitter pack.
A fully charged 3-cell Li-Po pack puts out 12.6 volts.
This higher voltage can overload the power-regulating
transistor causing damage and or failure, possibly
in flight. Many of our customers have experienced
failures using 3-cell Li-Po packs and their use in JR
and Spektrum transmitters is highly advised against.
The X9303 2.4 system will operate for over 15 hours
using a 2700mAh Ni-MH battery.

And Sweet, he was using an AR7000 rx - I don't think those required the user to glue down a capacitor. I also didn't read anywhere that he got shot down or had any major problems when he was on 72mhz, just the normal glitch here and there, like we all get - or at least I always got...

I think that is ultra lame that you can point your spectrum antenna at the plane and lose signal. WTF over?? Who ever thought this up as being a good idea should be fired. If you cant point the antenna at the plane then that is a stupid system. I know they say not to do it but still i never had a problem with my 72mhz radio ever losing signal because of that. 2.4 is not as advanced along as they should be. Too many people losing there high dollar planes because of under researched equipment. When they do finally perfect it, i might change over. but i want peice of mind more than anything.

does the Futaba fasst system have the same problem's or is it really "technology superior"

I picked up a blade cp heli on MHz to screw around with on rainy days. while hovering i got some glitches when noticed it only happened when i pointed the antenna at it.

Originally Posted by Extra nuts

I think that is ultra lame that you can point your spectrum antenna at the plane and lose signal. WTF over?? Who ever thought this up as being a good idea should be fired. If you cant point the antenna at the plane then that is a stupid system. I know they say not to do it but still i never had a problem with my 72mhz radio ever losing signal because of that. 2.4 is not as advanced along as they should be. Too many people losing there high dollar planes because of under researched equipment. When they do finally perfect it, i might change over. but i want peice of mind more than anything.

When was it determined that it was the fault of the 2.4 ?
I agree with Aviti--if it was a loss of signal then the failsafe should have kicked in--

sorry to hear of the loss

Hold the phone!! Its is simply not a true statement that you cant point the antenna at the model with Spektrum. It is not critical at all, though as with any signal propigation, it is better if the antenna is pointed up. i.e. just rotate the antenna 90 deg up, though it works fine regardless.