Futaba 2.4GHz problem

[Trevor Heley]

As anybody had a similar problem?

I had my original 6Ex 2.4 GHz Tx replaced by Ripmax in the replacement programme.

I was flying on the 18th Sept. when the following happened. Through the previous night  I fully charged my Tx and Rx batteries. I was in my 3rd flight of the day [2 x 10 mins + 6 mins] when the engine cut out and the plane banked and crashed into the ground.. I have an onboard Rx voltage meter and prior to take off was in the 5good indicator position [positions are 1low, 2 low, low, 4good, 5good, 6perfect and 7perfect] - Major damage -wing replacement , fuselage and stabilizer repair.

On 20th Sept. I was fyling again to test out after my repairs. Again I had fully charged my Tx and Rx batteries through the night before. I completed one flight - 10 minutes. On preparing for the second a worrying thing happened! On switching on the Rx both the throttle and aileron servos went fully anticlockwise. [both are set to normal {not reversed} on the Tx]. I experimented with switching on / off both the Tx&Rx. I also manually adjusted the position of all servos and on Rx switch on the rudder and elevator reset to neutral and the throttle and aileron servos went fully anticlockwise. I fly Mode 1. Movement of the left hand stick produced expected movement and the right had stick [throttle and aileron] no response. The on board voltage meter was reading 6perfect. I packed up and went home.

At home I could not reproduce the condition. I checked over a 5 day period as I let the ran the batteries down without being able to reproduce the condition.

Ripmax supplied with a second replacement Tx. I have only made 1 flight since then. On taking off to undertake a trimming flight prior to my A test  the plane  rolled and looped and destroyed itself. I am a "leaner" so this crash may have been my fault but I cannot rule out it may have been due to a Tx / Rx problem?

I am worried about using the Tx / Rx again due to the ongoing crash costs and of course possible safety issues. I am disappointed with Ripmax non-response to E-mails, letter and phone calls but that is another matter. 

Anybody had a similar problem? 

[Former Member]

[This posting has been removed]

[David Ashby - Moderator]

Trev I took your pics out as they weren't working...

Hmm strange one and good thoughts from Eric there. I have lost two models over the years in similar circumstances ( a slow roll into the ground) and have put both down to receiver battery failure. I think it's worth changing the rx pack - have you cycled the pack on a charger and seen what it's capacity is like?

[Tim Mackey]

And exactly which Rx battery pack are you using?

[260 Flyer]

Trevor

The first incident does sound like a genuine loss of signal because the fail-safe closed the throttle.

The subsequent problems could be due to damage caused by the first crash. The 6EX on switch on may cause a slight twitch on the servos as they re-center but nothing more. That is assuming you are using Futaba or other reliable servos, as some cheap servos do their own thing at switch-on, including driving past full throw and destroying themselves.

I have seen similar erratic servo behaviour in I.C. powered planes when the servos have not been isolated from the airframe by the proper use of grommets with a good clearance all around the servo.

I think your best course of action would be to persevere in contacting Ripmax and send the complete outfit back for testing.

Good luck.

Rob

[Ernie]

Hi Trevor,

Rob is right, you just can't take chances with something like this. It's not breaking the model, it's breaking somebodys skull. Send the whole thing back to Ripmax. I've found them very good, if you can get through to the guys who actually do the repairs

ernie

[Trevor Heley]

Thanks for your responses.

Eric - I have not had 2 duff Tx 's. The first one was returned due to the Futaba replacement policy due to the 2.4 GHz coding issue. All the problems have been with the second unit. I don't think charging of the Rx battery is a problem.  I have an onboard voltage monitor which gives "expected" results full perfect to poor as the battery discharges. I did a full range check without problem. On the second incident the plane was next to the TX? The aerial is set up as the Futaba instruction at 90 degrees and away from metal.

Timbo - The Rx battery pack is the one that came with the Futaba package which included TX, Rx, servos and battery back in January this year. [9 months old?]

Rob - I agree loss of signal should failsafe the throttle,  but why would the ailerons servo go full travel aswell? On the second incident why would the throttle and aiIerons servos be "locked up" where the rudder and elevator  servos operated as normal? I am using the full Futaba parts that came as a package. The Futaba S3003 servos are supported on the gummets. On the second incident the engine had not been started. I have suggested to the supplier that the Rx may be the problem and maybe it should be replaced?

Ernie - I can never get through to the right people at Ripmax  and nobody rings back or answers my E-mails or letter. I suppose I have given up too quickly - I will ring them again in the morning.

[Former Member]

[This posting has been removed]

[Martin McIntosh]

Sorry to hear about your woes. My original Tx pack died after 20 mins. use every time and was replaced with a 2400mA/h which lasted all day. Could this be your problem?

[Trevor Heley]

Dear all who posted. Just to let you know what has happened.

After various discussions with Ripmax they agreed  to replace my Futaba 6EX-2.4 Tx and Rx. They provided an "uprated" model a  Futaba 7C-2.4. I received the replacement in December 2008. I have had limited flying since then. I hope the coming season will be trouble free?

 

[Ady Hayward]

Hi,

I had a similar problem this weekend with the Futaba 6EX 2.4GHz system. Flying a Multiplex Mentor fitted with a 3A Bec. The flight was going well and around 4 minutes into the 8 minute flight when the aircraft started an undemanded roll right and dive. I throttled back, and tried recovery to no avail. Rudder, elevator and aileron were each tried in turn during the steep descent with no effect seen. Post crash inspection found all servo connectors were in position in the receiver, the wing connectors had seperated as the wings parted company. Everything worked after the crash including a range check after. The same transmitter was used several times later in another aircraft (With different receiver) without problem. Seems another flyer had a similar problem earlier in the day.

 

Adrian

[Delta Whiskey]

Sounds like you got a good deal in the end Trevor with the 7C !

 

I have the original Futaba 6EX 2.4GHz system I dediced not to get it replaced at the time, (not sure I can still get it replace now??)..........as I'm the only one (I think) in my club using Futaba 2.4, (all Specy) as far as I've seen so far.... this was with the 606 RX, and I orginally had it in a 450 heli, and used for about a year and half now with no issues ......it's now in a flying wing which I hope to maiden tonight !  

 

I have the 7C in 35 mhz, and lost two planes down to what I think was glitches & pilot error trying to recover..., so will gradually buy more 2.4 rx (617's)...as I've found them very reliable, even when I've done stupid things, like turning on & off the TX without waiting the recommeded 5 sec, and switching on the RX first......it was still in full control of the RX and servos.

[Trevor Heley]

Adrian

Sorry to hear of your crash. What does " another flyer had a similar problem earlier in the day" mean?

Trevor

[Ady Hayward]

Hi Trevor,

I was told that another flyer had a crash using his Spektrum system. It was muted that maybe mobile phones were an issue but I think not.

I believe my issue was maybe a drop in voltage causing a brown out as I had just completed a flick roll using full stick deflection and powered up to full power during the exit. The system had four servos in use driven via a 3A 5v BEC so maybe I had an instant of excessive current draw.

From what I now understand one of the micros that drive the binding process may have reached a low volt threshold and stopped. As the rest of the receiver was still operational it could not go through the normal binding process as would happen if the receiver had been completely switched off then powered up so the system remained live with no means of reactivating the binding process. 

 

Thanks

Adrian

[Tim Mackey]

I have never heard of such a thing before.

A chip that controls the binding process reached a low voltage threshold and stopped? Who says this ??

The easy way ( and confirmation by design ) of detecting a brown out is the flashing LED on the RX after landing - did you check for this?

[Ady Hayward]

Hi Timbo,

The suggestion of the micro was made by one of our RF engineers who did some work with similar micros, so having seen similar things with  a product from a reputable company (Not model related) it sounded quite feasible. Unfortunately the lipo in use was severely damaged and had removed itself from the aircraft. The system was tried with another used battery and powered up ok. All functions and controls operated normally as was a range check.

I'm away for a couple of weeks so cannot carry out some controlled tests just yet which are planned to explore this idea.

 

Regards

 

Adrian

[Ady Hayward]

Hi All,

I managed to get some time with the system and our engineers this morning.   The system flown is: HobbyKing Guard 40A ESC with 3A /5V BEC DC 5.6V-26V. Futaba R617FS FASST RX, 2x Futaba S3003 servos and twoTGE 0001 servos. Motor is different being a 55mm DF unit for convenience.

We set up the airborne system powered from a power supply at 12v nominal drawing 0.2A with four servos in connected at idle 18.78A with a motor at full throttle (55mm Ducted fan). All servos operating together drew less than 2A and with two stalled got the max amps to 2.7A. The supply voltage was reduced whilst stirring the sticks. The Motor stopped at 9.6v, and the servos started to be noticeably slower as the voltage reduced further, with the RX losing lock (Red LED) at 3.6v. As soon as the voltage increased a little the RX came back to life, re-bound and continued to work.

 As a result it would appear there is nothing wrong with the rx, and the cause must be down to a break in the main supply or something similar. The LiPo was held in with velcro under the canopy (Which was close to the fuselage on recovery) so it is possible it could have come loose and worked rearwards over the receiver disconnecting itself in the process.

 

Adrian

Edited By Adrian Hayward on 03/09/2009 13:40:37

[BB]

Is it possible that the ESC is located in such a way as to be ' too close' to the fire wal (i.e. noise! l; Or, that ventelation of air from the ESC is impeded causing overheating?

 

The Futaba has a number of 'builtin' safety features that SHOULD  stop an 'immediate' malfunction.

 

BB

[Ady Hayward]

Hi BB,

The ESC was placed in the chin intake to maximise airflow over the unit. Multiplex have generous airways through their range and have done an excellent job on the Mentor. From the testing carried out, the airborne system performs well better than thought originally so the "Brown out" would seem to have not happened. The motor was not under power when the plane crashed and none of the flight controls had any effect on the way down for the several seconds it took to descend. Our conclusion is that there must have been a disconnection of power to the receiver by either a failed battery or released power connector.

The photos show the new Mentor with the velcro mountings in place as was the set up on the one that crashed. The second pic shows the systems fitted.

 

Regards

 

Adrian

Edited By Adrian Hayward on 04/09/2009 02:15:54

[Former Member]

[This posting has been removed]

[Ady Hayward]

Hi Eric they are just aft of the rx heading rearwards at 45 degreesto the centre line. I have some golden rod inner to guide them through the fuselage sides and have the exposed tips of the antennae uncovered there is around 30% of the whole antenna length outside the fuselage. The servo wires are taped in to the upper fuselage sides to keep them away from the antennae.

 

Cheers

 

Adrian

[Former Member]

[This posting has been removed]

[Ady Hayward]

Hi Eric

the antennae are flat on the fuselage floor, one pointing 45degrees to the left rear quarter, and the other is pointing to the right rear quarter so i have acheived the 90 degrees separation with what could be seen as horizontal polarisation as opposed to the vertical polarisation as you describe. It is my belief (Maybe mistakenly) that as the aircraft is continuously manoeuvring relative to the transmitting antenna it makes little difference within the short distances the model is flown from me (It was less than 400metres away where it crashed). I agree that if the aircraft were to be flown in level flight at extreme range then the antennas should need to be placed in the optimum position given the direction and altitude flown. In the case of the Mentor, I would have had one antenna going upwards around 20mm from, and parallel to the aileron servos Y lead and the horizontal on eto the rear would have had the rudder and elevator servo leads running parallel within 30mm which I thought to be indesirable.

 

Adrian

[Adrian Smith 1]

I think I must be thick because of my inability to resolve a servo problem! I am fitting mechanical retracts to my Cmpro Mosquito using two Supertec S136GH retract servos and my Futaba 6EX 2.4GHz set. Servos are connected from a y-lead into the gear channel, in this case channel 5. The End Point Adjustment (EPA) is on it’s default setting of 100% which is too great and the servo arms rotate too far. However, when using the EPA facility of the gear channel to reduce the throw to 50% nothing seems to happen and the servo arms move the same as the original 100% setting. I don’t understand this at all or how to alter this. This is my first attempt at using retracts although I quite happily change the EPA on the other channels without difficulty. Any ideas?

[Tim Mackey]

Dedicated retract servos are non proportional and the travel cannot be altered.