aris1

My Feedback: (3)

Good morning modelers,
I would like to report 2 crashes, that happened to me a few days ago. A few months ago I decided to upgrade all my airplanes to 2.4.
After 20 years flying with JR without any problem, I ordered from chief 5 JR 921 (2.4) rx and the spektrum module for my pcm10x radio.
I installed the first rx into a little electric plane (tucano, from phoenix) to check if everything was going to be okay.I flew the little, tucano
for a month , having the JR921 rx only with one remote rx, and everything OKAY.So I started to install the other 4 JR 921 rxs, into 4 giant planes glow operated.I flew all my 4 giants airplanes for 2 months using this time 2 remote rxs, WITHOUT ANY PROBLEM.A few days ago I
took my little electric tucano for a flight, and just after lift off the airplane went into an ABRUPT CONTINIOUS ROLL AND CRASHED!!!!!!
I tried to recover but it was so quick, and so low.I immediately removed the JR 921 rx and the remote one and installed it in another little
electric plane, and flew it immediately WITHOUT ANY PROBLEM. So I repaired the little tucano, and did reinstall the Jr 921 rx and remote
into it and EVERYTHING OKAY. In the mean time I am also flying all my giants without problem.Yesterday I took the little tucano for a flight ,
and just after lift off the airplane went into an ABRUPT CONTINIOUS LOOP THIS TIME AND CRASHED!!!!I again immediately removed the JR 921 rx and remote and installed it AGAIN in another electric plane, and flew it immediately WITHOUT ANY PROBLEM!!!!!I really don,t understand what is happening. I called horizon hobby and they told me to send all my jr rxs and the spektrum module for them to check.
PLEASE HELP! Anybody with an opinion? For information the little tucano was equipped with an AXI 221220 MOTOR and JETI ADVANCE 30 AMP, ESC,AND THUNDER POWER 2200 MAH,3S LIPO BATT.The tucano was flown in my backyard . ALL my electric planes are flown in my backyard
. THE big ones are flown at the club.I have been flying the electrics in my backyard using JR pcm rxs for 10 years without a SINGLE problem.I would like to report also that the axi motor was operating outside it,s amp range (max 18 amps)I was at 28 amps due to the
SIZE of the prop.CAN THIS PROVOKE UNCOMMANDED SERVO INPUT? Today the TWICE CRASHED JR 921 RX flys in my backyard in another electric plane (with an axi 221226 motor this time and another JETI ADVANCE 18A ESC) WITHOUT PROBLEM.A friend of mine told that the esc is the cause of both crashes.Also during both crashes all the other channels were responding normaly!!!!!! I thing that I AM GOING BACK TO MY OLD TRUSTY JR RECEIVERS. Thank you for your patience, and your help,and keep on modellinG!!!!!!!

Bundubasher

This is scary - as I'm in the process of converting to 2.4 on all my planes as well.

I've had twice a similar problem with very much the same size motor and controller - But with 35 mHz Tx. It turned out that the receiver was too close to the speed controller. I separated the 2 further apart and the problem was gone.
But this was on 35 mHz and not 2.4 - but try it - maybe the 2 components (or that 2nd Rx thingymajig that is supposed to be 90 deg offset to the main Rx) are too close together in the Tucano..

It will be very interesting to see what the supplier advise.

aris1

My Feedback: (3)

Dear bundubasher,
I know that the remote receiver was almost touching the esc,but horizon hobby told me that this is NOT a cause for trouble.!!!!!!
What scares me most is as I said before :I have 4 giants scale warbirds equipped with the same JR 921 receivers.I did almost one year
of building (scratch building)for each airplane, and you understand that if this happens with one of my beauties!!!!!!! Okay a little tucano
crashed, no problem.But a big mustang with approximatelely 22000 rivets (hand made!!!!!)I forgot to mention that after the second crash
I had with me a data logger, and it showed nothing!!!!!No fades,no holds , no frame loss nothing. If I was sure that the esc provoked both
crashes, okay I would not use 2.4 in my electrics. But as I told you the crashed JR 921 RX and remote fly almost every day in my backyard without problem.Okay it is not the same power axi motor and not the same rating jeti esc. I am going to mount the twice crashed
jeti 30a esc and the 221220 axi motor on a test stand with the same prop, and make mesurements to see what is happening with the BEC
How is life in south africa. I am a retired Airline capt , and I use to fly to Jobourg twice a month. You guys have one of the beautiful country
on earth!!!! Especially for modeling, I am sure that i will agree with me. Best regards. ARIS

Bundubasher

Hi Aris,

You too live in abeautiful part of the world.

The speed controller creates a strong electromagnetic field and may interfere with other electronics close by, especially receivers. Space is a problemon some small electrical planes and the electronic components are too close - within reach of this field - I had that.

I also had once 2 differentbrands of Deans plugs - looks the same but did not make good contact - check this - have everything plugged in and running and wiggle the wires - like you will wiggle abeautiful Greek girl in dance.......... to see if it is not a bad contact.

But it is best toget professionaladvice from the supplier of your2.4 gig stuff - it will definitely hurt to hit the 3rd rock from the sun with a beautiful plane....

Hey, when you solved this problem, pour yourself a Tsipouro grappa and.....

Johann

jerdavis

My Feedback: (3)

BEC input voltage will limit the number of servos the BEC can support. The higher the input voltage, the fewer servos you can use. You may be driving more servos than is recommended, and having receiver "brown outs" that will lock up the system for a moment. I would think that with a higher than usual amp load by the motor, you would be just asking for a "brown out".
Check the BEC operating manual for the number of servos supported.

Jerry

Rafael23cc

My Feedback: (6)

Could this be your problem?

[link]http://spektrumrc.com/Articles/Article.aspx?ArticleID=1693[/link]

The article has a date of 2007, so it might not be your problem, but it is worth looking into.

Rafael

aris1

My Feedback: (3)

Johann, thank you for your good words concerning my country. When the problem will be solved, I will definitively pour myself a glass of
TSIPOURO and enjoy.Concerning my connectors I use sermos (power pole) for the last 10 years and not a single glitch!!!!Anyway thank you again for your help.

Jerry, I know that the maximum servos I can use is 4(for the 30amp esc)My little tucano was flying with 4.So I don,t thing that the problem
comes from there. I have 2 other electric planes same size as the tucano, using both 18amp jeti esc where I use 6 servos (I have flaps on both)instead of 4 and I have been flying like that for the last 5 years without problem. Anyway thank you again for your time and opinion.

Rafael, I am aware of the spektrum JR 10x module bulletin. Before flying with 2.4 I saw the bulletin and I called them to ask what to do
because, I WAS MEETING ALL THE CONDITIONS OF THE BULLETIN.They told me that because I baught my 2.4 in 2009 that the reprogramming was already done , and not to worry.Thank you for your time, and opinion.

duworm

Hmmmmmmmmmmmmmmmmmmmmmmmm.

If I get this right, it is the same plane that did its own thing twice. In both cases, the Rx was removed and worked fine in a different plane. If that is the case, it sounds like you have eliminated the Rx as the problem and all that is left is the plane or the physical relationship between the Rx and something in the plane.

I had this same problem come up flying 72Mhz. Crashed the same plane twice. Pulled out the Rx both times and it worked fine in a different aircraft. I finally tore out the wiring harness in the plane, replaced it with a new one and problem solved. Looked over the old harness very carefully and never did find a problem with it.

Electrons are funny things, and even harder to see.

Sherman Knight

aris1

My Feedback: (3)

Dear sherman,
Thank you for your support. As I said ,I am going to make measurements on all the failed equipment to try to find out what happened.
I will also check the wiring harness, you are right ,because despite the fact that it is a good quality esc (jeti advance) their switches don,t
show much quality.I am scared because as I said to the other guys, I have 4 warbirds (hand made you understand)equipped with JR 921
receivers. I will put back my old trusty JR pcm receivers and continue to fly and make tests with the electric one equipped with 2.4
until I will be 100% sure. Even if it takes 2 years of tests I don,t care.Thank you again.


Aris