jonty

Hi all

We on Sunday my beloved Boomerang nano came to grief and is now balsa popcorn. I wanted to post the details of the crash on here to see if anyone might be able to help in diganosing. My gear is as follows

1. JR9X (X9303) 2.4 TX
2. Spektrum AR7200 RX
3. Turnigy powerboard
4. 2cell Lipo RX batt (regulated by powerboard)
5. Jetcat p60
6. High end metal geared servos

Ok, so I was flying the downward leg in a flat level position when suddenly there was a right aileron command given somehow and the Boomer rolled to the right and into a nosedown dive. By some serious luck as the Nano hit nose first and the turbine let go from the bracket an landed in a long patch of soft grass and is completely intact. All electronics bar the I/O board are fine. The fuel tank seem to shoot out one way and the turbine the other so no fires or electonics damage we can see so far.

The weird thing during the flight that happened was that the elevator trim was out by almost 10 clicks (it had been set perfect the day before in the same conditions). In know that radio had bound properly as I has checked all lights were solid (the flight the day before I had noticed the satellite light blinking so re bound). It was also on the right model and no radio settings were touched . I am yet to check the failsafe settings but I would have expected that if it was a lockout it would not have rolled. Further, the battery was fully charged and seems fine.

My thoughts so far:

1. I noticed the right hand aux 3 slide lever is activated on Aux 3 (which means I could have bumped it). I need to check tonight but I would not expect that to affect the ele or aileron as I was only using a 7 ch RX with aileron on a Y lead on the Aileron channel;

2. the turningy powerboard has somehow developed a fault and is sending stray signals

3. there is something up with the TX or RX

Ideas of what to check are welcome

Cheers

Airforce7

My Feedback: (31)

What is and why are you using a turnigy power board?

john491

My Feedback: (13)

Was the aileron y harness a reversing type?
John

jonty

What is and why was I using a Turnigy power board?

Because the Nano was second hand and the previous owner had used it without any trouble for sometime. It is essentialy a voltage regulator power board which takes a 2cell lipo and powers the servos. The board also takes in and puts out the servo signals hence my suspicion (it will be binded trust me). I had a search on the HK site to get a link but I can't find it on there.

On the Y lead, I did not install that as again it was second hand so will need to check tonight but i don't think it is a reversing lead.

trioval00

My Feedback: (17)

last year, 2011 at the last day of the Hamburg jet rally, I was decided to fly my Skymasters L-39 as I spent the other 3 days burning 10 gallons in my Boomer XL.

Just after take off I was making a right turn, she acted weird for just a quick second, the aileronbanked the L-39 hard over on the right, I gaveleft aileroncommand and she came back, a second later she rolled over to the right again, again left aileron stick and she responded and leveld out again, then she rolled a third time. All 3 times were right aileron movement. I yelled "Mayday" turned sharp right and brought it in without any damage.

all this happened with in a few seconds as I only made 1/2 lap around the circuit. And during this I had full control on the L-39, even though she still wanted to roll. When she did roll the 3 times, it wasn't like the control surfaces were out of trim, but were like I gave hard right stick.

landed and brought the jet back to the pitt area. I checked every connection, range checked it 3 or 4 times. I plugged the data logger in and thats when I found my problem. After logger was in, I did 3 more range checks. Radio is JR2.4 9303. so after I did the walk with finger on the button, I checked the data logger, got the usual reading on most of the remote receivers, but one read "999"...... there it was, I had a bad remote receiver (satalite) The receiver I believe was a R922. but after this mishap I changed the entire receiver set up and I went with a different one, I think it's the R1222X, and No more problems ..

Mark

jonty

Mark

Many thanks for that. What you describe is very much what happened to me although I was having trim issues intially (and I wasn't quick enough to save it like you!). I am only running the AR7200 with one satellite RX so I will put that in a park flyer and give it a good thrashing. I will be replacing the RX with a JR RX with mulitple satellites and chucking the power board. I just really hope it is not an intermittant TX issue as that it is just so hard to replicate that.

Also whether it matters or not but when it rolled it the RX and satellite woudl have been in the worst position as it was 200 meters downwind and level and the signal would be having to go past the turbine etc.

I just would have thought for me (and you) that fail safe would have kept it level had it been a lockout

John

Pegasus

I had the exact same problem with two separate aircraft, one with a AR 9100 in and the other with the Ar7000 in it. It did not seem to affect the other channels just ailerons, I would post the video of this but the language I was using at that point would get me in trouble. On one incident it was at El Mirage Dry lake bed the other was at the Supulveda field, 100 miles apart. The only common factor between the two aircraft was the transmitting module and transmitter I have flown this transmitter many more times with foamies on the 72 mhz module and no problems. I could not put the data logger on the AR 7000 because it does not work with it and the aircraft with the AR9100 in it was a complete write off and everything was disconnected at the crash site. Could there be electrical interference with high voltage ESC's or electrical equipment that causes this? I would really love some answers to this. I am ready to try the new aircraft this weekend, although I have replaced everything in the plane if it has something to do with high voltage electric planes I would like to know about it now. I am glad I am not the only one that has seen this

Pegasus

john491
One of my planes did have a y harness with reversing on flaps, why did you mention this?

john491

My Feedback: (13)

Spectrum has a awarning about the reversing y connections. I believe that it counts as a powered reverser and they cause glitching just as you describe intermittently. I even had several do this to me as I converted from 72mhz to 2.4. As a result I have retired all of my reversing y's. Now I use a second channel, reverse the servo, use a brand of servo of another brand with different direction of rotation, or make sure the linkages are set up not to need reversing.
9303's also have a 'notam' about frayed wires on the aileron pot as I remember. That's easy to check by opening the back and checking the pot wires. It's on the JR site as I remember.
John

invertmast

My Feedback: (23)

Reversing Y harness' and extensions with chokes are said to not be used with the spektrum/JR systems (not sure about futaba). Look at the don'ts in the link

http://www.spektrumrc.com/Experience...Practices.aspx

rcjetsaok

My Feedback: (7)

Is the Tx and RX both DSMX or DSM2 protocol, or one of each, and if so which is which ????


Danno

jonty

Thanks John

Will open the back of the TX tonight and check the wires.

jonty

Both DSM2 I expect

Pegasus

I just remembered my second plane had this reversing device on the nose gear servo, can this affect ailerons?
FYI My transmitting module and receiver were the package deal from spektrum.

john491

My Feedback: (13)

It's probably not worth your plane to find out. In my case the interferance was intermittent and fortunately detected on the ground after some in flight 'wierdness'. Make the change over in direction mechanically if possible.
John

mirce

I use JR Match box for that...

Mirce

sieze2

The Nano only has one servo driving the airbrake, it has no flaps? Are you talking about a y harness for the ailerons ?

essyou35

My Feedback: (11)

To me, given the elevator trim issues, then the roll to the right, it sounds like you may not of had a boom bolt installed correctly.  There are several  videos of this type of error on youtube.  If you did have it installed, maybe the mount where the blind nut is gave out.

If it were a radio issue it would make sense except the elevator trim issue leads me to believe a mechanical issue.  A lost connection or "hold" as they are called wont cause a trim issue.  It basically just does something uncommanded for a short time then stops if it gets signal back.

ChrisPetersen

My Feedback: (3)

Those reversing y's can be bad news. I know of a guy who could not turn on and off his receiver without the y'd surfaces changing trim. Of course he flew anyway, I think the crash is on YouTube now. This of course is worst case scenario but from that and my experiences having them drift I would steer clear of them if you can. My2c

Sahevaan

Incase you are using the back stand for the Tx , for certain modules for the tx , the range check button gets pressed . The same thing happened here with a fellow flyers jet .

ynonorr

One thing you need to remember is the blinking satellite receiver (from the day before). That means a low voltage event, yes the system did unbind
and rebind but not do to a radio problem but to a low voltage problem.[&o]

So I would be more interested in the failsafe settings than any thing.

just one more thing to think about.

Bob

luvthestang

My Feedback: (172)

if your fail safe on the radio was triggered and set correctly your turbine should have also cut out. This would have been a clear indication of lockout. If your radio failsafe was set correctly. IE bind with stick and trim in down position.
D,

jonty

Thanks guys - all good ideas. I will test them all then report back.

John

Jackjet

My Feedback: (1)

This is why I will not use a 2.4 system.........yet - at least with a 72mhz you MAY have a chance of landing it.........

Jackjet
Rabbit Dry Lake

Fred L

My Feedback: (2)

i have had one or both recievers flashing <satalite and main>. i like to see the lights solid before i take off. also had signal boosters in servo extensions cause problems