Problem with Mercury SRS gyro with 18MZ

  • Fortunately I was able to level the aircraft before impact and therefore there was very little damage to the components, see the attached photo. All of the control linkages were inspected at the crash site, everything was still connected. I checked all of the control surface servos when I got home, they all seemed to be working properly, however I need to mark the two aileron servos as possible suspects.

    I had 26 flights on this aircraft when the crash occurred, I agree that it does seem unlikely to be turbine noise on the 26th flight. If I were to send you the Mercury is there some kind of diagnostic test you can run on it to make sure there is nothing else wrong with it?

    Thanks again for the help,


  • Hello,

    we will replace the unit for two reasons: it was involved in a crash, and you are using it in a jet . To be safe for this two reasons in the next model, you get a new one.


    I appreciate the offer to replace the device involved in the crash, what do I need to do to get that going?



  • Thanks Danny, I will put it in the mail tomorrow. I really appreciate the help from the whole Powerbox team. Should I send the switch, display, and the unit? Or just the unit. That display you sent me last week was for this unit (the ribbon cable on the other display was damaged in the crash), so the display is new.

    Best regards,


  • Hello Richard

    I have previously submitted a thread in which I was querying mode selection when using 2 x Futaba 7008SB Rx

    The reason I asked as I had a catastrophic failure of my brand new HAVOC SS which was complete with the following equipment

    1 x Mercury with GPS and mercury set to 12ms

    2 x 7008SB Futaba Rx 1 set to mode B the other set to Mode D

    2 x futaba 9157 on elevators

    2 x futaba 9157 on ailerons

    1 x futaba BLS157 on rudder

    2 x savox 1256tg on flaps

    1 x Macgregor MG7245HV on nose steering

    1 x GS200 landing gear controller

    1 x Jetsmunt 200 turbine

    1 x Futaba 18SZ Transmitter

    I must state I am not trying to blame anyone I feel that I have probably done something wrong somewhere along the line and am trying to understand where the problem was so I do not make this mistake again.

    All ground testing of the model with turbine running and off showed no bad habits all appeared stable, so I went for the maiden. For this I left the Gyro switched off on the mercury and left it in FM1 and I did not engage the test flight assistant

    The havoc ss accelerated down the runway and took off with a squeeze of up elevator, I raised the UC and flaps the havoc needed no correction to ailerons but was climbing slightly, I made the up wind turn all felt good, flew the down wind leg and compensated on the elevator stick for the slight climb, I turned around on the downwind leg, came back into wind and trimmed the elevator, everything at this point felt great and I made the upwind turn come back down wind shortly after making the turn the havoc ss violently went to knife edge without any input from me and took me by total surprise, I corrected it to level and it responded as would be expected back to level at this point I thought I have a major problem here and must land asap. approx. 2 second later the havoc violently snapped as though I had put all controls to 1 corner which I hadn't and then spiralled in I could not regain control, and shut the turbine off, which I do not know if this action at the trany or the failsafe having shut the turbine down anyway there was no fire and no one got hurt

    I have uploaded 2 pictures 1 of the Havoc SS just after it was completed and the other after the pieces had been picked up after the maiden, unfortunately no photos were taken at the crash site I and a number of other model flying friends were guest at a club in France when the accident happened and it was of the upmost important to clear up the mess as quick as possible and I did not have a camera with me initially which is why the pictures are after I stripped the Havoc down all the bits that were salvaged are still in those black bags

    I have 2 friends who also have brand new havoc ss we brought them at the same time and each has very similar setups they are both using Mercury with 7203SB RX and different mix of servos and there's works perfectly

    I have been flying Turbine powered Jets since 1997 with no previous problem that I could not locate

    I have used plenty of power box equipment over the years and have had great success with it

    This is the first time I have used SBUS RX 7008SB and Mercury, I'm just hoping you maybe able to shed some light and I can avoid this problem going forward

    For clarity I continued to fly the week out with the Futaba 18SZ and Jetlegend 1/6th F16 complete with PB evolution, 3eIGYRO and 7014 Rx all worked perfectly along with other models I have



  • Unfortunately the ecu was totally destroyed along with the 2 Rx and most of the Mercury from the picture I sent u can see the remainder of the mercury on the centre board along with the 2 bottoms to the receivers and also the GS200

    As this was my first time with sbus receivers I had not got around to fully setting the telemetry side

    I had wanted to get the model flying first and then set up telemetry

    I have attached another picture of the electronics board

  • Hello,

    I´m sorry to say that but if you don´t find bad wires, servos or mechanical issues which may had occured it will be nearly impossible to find out the crash reason.

    As the problem occured 2-3 times with time in between it looks like a RF-issue. The PowerBoxes are digital from input to output. It works, or it doesn´t work- I state this because in the last 10 years with SRS technology I can´t remember to an interupting function.

    We can replace all PowerBox parts for 50% as usual because they are not repairable.

  • Hello Richard

    Thanks for your honest opinion, its kind of what I thought maybe the outcome. Last night I re hooked all servos on to a receiver and all are working correctly.

    1 of the 9157 servos has 1 missing tooth from the main large gear wheel and I feel this has probably happened during the impact, of cause I will not use these servos again as I cannot be sure of a potential failure with them going forward

    I would like to take up your kind offer of a new Mercury at 50% of cost, can you confirm how I go about this please