olnico

Hello guys

I'd like to give you a feedback from the first users of JR 12x system here in Dubai.

We just had a crash this afternoon due to loss of range.
The model was a 1 year old Velox that flew successfully for a long time on 35 Mhz.
The owner switched to the module based 12x and AR 9000 Rx.

The crash appeared on the first flight with the system. The owner didn't deam necessary to do a range check with this radio ( big mistake ).

The guy had a lot of luck since the lockout appeared after takeoff on a vertical climb. The pilot recovered some control and managed to get it back. While on base leg, the plane locked out during a pitch up action.
This led to a stall and crash on final. The plane did land on its tail in the sand with only minor damages.

After recovery and download of the flight log data here is the conclusion:
The plane got 2 hold conditions with massive amount of antennas lost for all 4 antennas ( up to 600 in 3 minutes)

We checked the plane on advance range test with the AR9000 and got a catastrophic result at 30 paces with multiple frame drops.
We then changed to a JR 1221 with the same TX and got the same result.
I then tried to relocate all antennas with no improvement.
We then tried another JR12x with the same poor result.

At that point I was scratching my head and decided to try my 10x with my AR9000 RX. Perfect solid results.

It looks like that the 12x transmitters ( both of them ) have range issues.

I have no more feedback at this stage but it could be a faulty batch of tx...

Doug Cronkhite

My Feedback: (34)

So because you had a single issue, with a single transmitter, you've decided all 12X's have problems? You haven't even tested a second sample yet to see if it's just a unique problem with your friend's radio.

noahb

My Feedback: (67)

Doug, he did not say all 12Xs have problems. He stated that the TWO they tested had problems and that it could be a bad batch of tx's.

seanreit

My Feedback: (60)

Hey Doug, he did mention that they tried a SECOND 12x. I would not condemn all of them, but I would be asking the same questions in the same way if I tried two 12x's and got the same result on range tests! I hope y'all get this worked out.

ianober

My Feedback: (12)

If both of you bought your transmitters at roughly the same time and location then possibly yes, a bad batch it could be, but I have used a couple different 12X's so far and had no problems.

Shame on your friend for not range checking first, it would have saved him a load of repairs.[:@]

Gary Jefferson

My Feedback: (167)

I would take the receiver out of the plane and do a range check on the bench...Gary

bevar

My Feedback: (27)

Maybe I have it wrong, but was it you guys who also lost some other jets on 2.4 a while back?

I seem to remember reading about that. Maybe 2.4 is not suited for where you live.

Beave

Gary Jefferson

My Feedback: (167)

I think it was one of Tam's A-4's that was very nicely customized but not sure...Gary

Doug Cronkhite

My Feedback: (34)

You're correct.. I misread his post. I thought he was condemning all 12X's..

My apologies.

Tom Antlfinger

My Feedback: (24)

I have installed the 1221 in 3 different planes, UB, Boomer XL, and BCARF......I have the dedicated 2.4 TX....Between all the planes, I have over 100 flights on 2.4 during the last 2 1/2 months. Never a glitch.

Range checks equal what I get on my 10X on 50 Mhz, i.e. about 100 paces or about 300 feet with the low power button pushed on the 12X in all 4 quadrants with the TX held clear of my body. The manual only requires 30 paces or about 90 ft.

I usually get either 0 or 1-10 fades. The most I have ever seen is 27. Never any frame losses.

I wonder if there is a problem limited to the module based TX?

seanreit

My Feedback: (60)

I think it was these guys too, but that became the issue with the mis wired switches. I would give these guys a lot of credit and not think they are misrpresenting anything. As far as I know, these guys DISCOVERED the problem with the switches, and it cost them a jet to do so, and then they shared the information and pictures with all of us, rather than just let us all crash.

I don't know them from anyone, but I don't think of them as chumps who crash jets, not saying you do, but your comment on the 2.4 I think is too early to say.

jetdriver

My Feedback: (1)

this is the same guy that was throwing rocks at spektrum radios a few months ago. I agree, the environment must have something to do with the problems. one 2.4 spektrum and 2 JR 12X systems that all won't work...........strange, very strange

acw

My Feedback: (1)

Oliver, could this be related to some large carbon fiber reinforcement? Carbon fiber in large quantity is a problem with all 2.4 radios. It became so bad with competition gliders that manufacturer now produce 2.4ghz version of their products.

Irregardless, It would be very interesting to perform a range check with the rx outside of the model.

Arnaud

Ehab

My Feedback: (44)

Is it possible these problems may be related to the non-us version of the 12X? I know that the 2.4 is not highly regulated in the gulf nor is highly monitered there, hence may have interference. As suggested, check the same Rx outside the craft with a bunch of servos and compare results with inside the craft... Another way is to install a fut 2.4 in identical location in the jet and see if you get range. Try to change one thing at a time and be scientific about it, not emotional[8D]

HotelSierra

My Feedback: (9)

Fellas, don't forget he tried his 10X with 2.4 module and an AR9000 and it worked perfect. This should rule out 2.4 not working properly in their region.

Ehab

My Feedback: (44)

Well, it actually depends on when he bought the 10X conversion. early units did not comply with the EC directive for 2.4ghz trasmission and were of US strength. Later units supposodly complied with the directive and had a sign on the box... This is one possible explaination (I am assuming proper insallation, by the way)[8D]

darryltarr

My Feedback: (2)

Oliver,

I think there may be some other facts missing here!!

I don't want to open a can of worms and get into a lengthy discussion about who knows more but this is what I observed.

After you had left the field the other night I was helping some guys with thier turbine and was approached by some guys to ask about my 12X 2.4GHz installation and if I had ever had any issues with it. It was only then that I heard about the incident with the Velox, so I spent some time looking at their set-up and was NOT supprised why they had issues. There is too much information to write down here, besides it will take me all day, but here are some obvious mistakes:

1. Using only ONE JR EA101 with the RD1221 Receiver
2. Wrong orientation on the EA101
3. Using 2" pieces of plastic tubing on the small antennas (THIS IS A RECIPIE FOR DISSASTER)
4. Not using a voltage regulator (preferably 6.0V), on the RD1221 RX

I am using the 12X 2.4GHz in my BVM KingCat with PERFECT RESULTS. I PERSONALLY THINK THERE ARE NO ISSUES AT ALL WITH THE 12X

THIS IS THE GREATEST RADIO FROM JR EVER!!!!

As we all know "A successfull and reliable model aircraft requires THREE vital steps": PREPARATION, PREPARATION, PREPARATION.

To convert a model from PCM to 2.4GHz is not as simple as replacing the RX, which as we both know is what often happens here in this part of the World. Ignorance is costly in such circumstances.

Regards,

Darryl Tarr

olnico

Our environment here in Dubai is not worse than anywhere else for using 2.4 Ghz systems. Most of the jets modelers here in Dubai have now switched to Spektrum/FASST systems.
I am flying with a 10x, air Spektrum module and AR9000 at least one day per week. I have owned air Spektrum systems bought from the States for the last two years and have experimented most of their early systems and versions. I have been recording the Flight log data on my flight folder for every single flight from the beginning and now have a good collection of samples to say what is going on with this technology. I am also doing range tests on a regular basis with my well proven system ( more than 120 flight with very few frames dropped ) and I know exactly how a good Spektrum system is supposed to perform and have been very pleased to see a HUGE increase in range performance from the early air module versions.

The typical range test will exhibit a solid RF link at 60 paces with frames starting to drop from that distance.
An optimized system will go up to 90 paces.
Please read my Spektrum technical review in the RCJI June/July 2008 publication for further information about the advanced range test procedure I am using.

Darryl, I have spent about two hours on this plane playing around with the components after the crash. What you saw this night was the plane state AFTER I did work on it. It was not representative of the flight configuration. The owner's worker also possibly removed components from the plane since we had to borrow some for the range checks after the crash.

The plane originally had 2 Spektrum remote receivers and an AR9000. The antenna placement was standard although not absolutely optimal. The guy had one Duralight regulator and the battery used was a big 4000 Mah Duralight. I carefully inspected the plane and the setup used and applied the evaluation criteria that I detail in my technical review. There was no carbon reinforcement in this Velox. The antennas were placed far enough from the ECU and all the metallic/conductive parts.
The regulator didn't fail during the flight and the power system was perfectly working after the crash. The guy didn't turn off the power until I retrieved the RF link data and there was no power interruption during this flight since the Flight log data was consistent. The electrical system test I did after the crash gave solid results.

I tried two different JR12x on the same plane and these two radio gave very poor results on the advanced range test. I believe that these radios were bought at the same time and there is a great probability that they are from the same batch.

After having tried two different 12x Tx with the same plane I was convinced that the plane setup/receiver was faulty. At this point I decided to take my own reliable system apart and I put my AR9000 with my own receivers into this guys plane. After rebinding the results were absolutely the same.
I was really surprised and I decided to use my own Tx to see what it would do. The following range test proved to be rock solid at 60 paces away. I did put back the original AR9000 that the guy had in the plane at first with the original antennas and binded everything to my own JR 10x. Once again the results proved to be perfect. We then rebinded the system to his own 12x transmitter and once again the results were really poor.
I then asked him if he could put his JR1221 with 3 JR remote receivers in the plane, which he did. After rebinding to the 12x the results were the same again and not flyable.

This is how I came to the conclusion that these two 12x transmitters have a range problem. It took more than one hour of work and I cannot see any other explanation at this stage.

I am not throwing stones at any particuliar system, my aim is just to give you guys feedback and make you aware of possible problems as I did previously with the AR9100 cabling issue.

I tried to persuade the owner of the radio to let me open the TX module to check the version and s/n, but he didn't want to. This is perfectly understandable since he was going to send the Tx back to Spektrum.
The radios were module based 2.4 Ghz 12x and there could be a problem with this specific category of TX and a batch of associated modules.

Guys just be aware of this possible problem. There is only one answer to this at this stage: NEVER FORGET TO DO A RANGE TEST before a maiden, after a rebinding and every month.

There is absolutely no doubt that this is the greatest radio from JR, however I did characterize a range problem with these two sets on this day.

olnico

Hi Sean,

You are right in you comment, it cost me a jet and not the worst one.
It is very pleasant to ear that this loss did help a few guys around and I thank you for the support. I'm flying to Texas quite often and I'm sure our path will cross soon or later in a meeting.

olnico

This is a very interesting feedback.
I have been using Festo clear 3mm tubing to protect the antennas from static electricity discharge for a long time. The idea is to avoid any contact between the fuselage/structure fiber surface and the antenna wire. The advanced range test did not show any difference with or without the tubing.
However I did try the black antistatic festo tubing ( ref number PUN3 ). I believe that this tubing is made of a plastic that includes some conductive material and is meant to carry the static electricity away thus avoiding accumulation. The range test was significantly reduced with this. It is a great product for fuel tubing and not for antennas protection...

Did you experience similar results with any specific tubing ? What brand, what color ?
I wonder if some specific plastic pigments could act as a conductor and reduce the antenna reception sensitivity.

AlW

My Feedback: (17)

Darryl,
I am interested in your comment re tubing over the Spektrum antennas also. I have been using a 10X with a Spektrum module to fly my Bobcat and Kingcat since the beginning of 2008. The Bobcat uses an AR9000 receiver with (2) remotes and the Kingcat uses an AR9100 with (4) remotes. Prior to installation I had covered all the antennas with 3mm Polyurethane clear tubing manufactured by Freelin Wade. The initial range tests on both airplanes yielded very low fade numbers on all antennas at the (30) paces as specified by Spektrum. Both airplanes are flown with Data Loggers installed and have always yielded low numbers. Prior to each flying session I conduct a simple range test at twice the recommended distance and again have always gotten low fade numbers.
However if there is some reason why the installation of this tubing might result in range loss then I will remove it. I had installed the tubing to protect the antennas and keep them straight never thinking about possible RF issues.
Al Watson

darryltarr

My Feedback: (2)

Hello Al,

Regarding the plastic tubing used in Your, Oliver's, and perhaps many other installations there should be no issues. WHY; becuase you guys have done extensive range testing and have also used sensible tubing. I am not sure what material was used on the Velox but I can guarantee you that there was no range testing done before the first flight after the modification.

As you know some plastic tubing can conduct very small ammounts of electricity, large enough to induce a good source for a static discharge, enough said.

Despite all the information thrown arround on this thread I still doubt there is anything wrong or faulty with those 12X transmitters in question. This is of course my opinion and I tend to speak my mind, so I hope I don't offend anyone.

JR quality control standards are second to none.

Regards,

Darryl

David Gladwin

I wonder why you chaps are putting anything over the antenna wires. I've never put anything over my remote rx aerials and never lost a frame (loggerchecked after every flight) on my Spektrums installed in two Bobcats and an L39., perhaps my ignorance is bliss. If you are worried about the internal metal of the aerial conacting something conductive why not just cover the ends of the wires with a tiny piece of heatshrink or perhaps a tiny blob of epoxy ? I see that Darryl mentioned that only ONE remote was connected to the main 1221 receiver but the manual (P1-16) clearly states that that at least TWO must be connected for the system to work, could that have been the real problem ?

Just received my two 12Xs. one on 2.4 the other on 36 Mhz PCM. Beautiful pieces of avionics and I'll do a range check tomorrow. but my Spektrum ranges are WAY over the 30 paces suggsted in the manual, more like 90.

The first 12x on 2.4 in a jet in Australia flew very frequently last weekend at Temora, Flash with JC 160, zero problems, like everyone else on 2.4, both Spektrum and FAAST mine will be airborne soon.

Regards, David Gladwin.

olnico

David, this plane flew and crashed with a AR9000 and two remote antennas.
I am trying to get this transmitter from the owner to do some more tests.
Not sure he didn't send it already though...

Tom Antlfinger

My Feedback: (24)

I have been using Festo clear P.E. tubing from the start on my 1221's as I found my self always bumping and bending the antennas.

It has the ID: PUN-H-3.0x0.5.......I cut pieces in between the lettering on the tubing. I wasn't sure if that ink could cause a problem.

As I noted previously, range checks on all my 1221/12X setups approaches 100 paces with minimal fades and zero frame losses in over 100 flights.