Mercury vs iGyro SRS

  • I’ve a yellow aircraft F15, similar size to the legendary avonds F15

    I previously flew the model with an iGyro SRS, with the older software where you adjusted all three axis during one setup flight. The iGyro made the plane feel great.

    I’ve since changed a lot of other components, (new engine, pipe, electron retracts) but I added a mercury SRS.

    The CG was checked on xicoy scales and it may be slightly further back, but not more than a cm.

    I’m surprised that the model feels so different. There’s a terrible wing rock. Setting the gain to 83 percent didn’t help. Setting it to 100 percent helped slightly more, but it’s not perfect.

    I even landed, and set a slider to allow me to adjust rudder gain independent of aileron and elevator. I was concerned it may be Dutch roll, and didn’t want the aileron and elevator gyro action to mask it.

    So the question, should a plane flown with an iGyro SRS behave the same as when flown with a mercury? My thoughts were that it should.

    If so, I’m confused what could be making such a difference.

  • The wing was rocking, (on the roll axis) oscillating due to the wind. We increased the gain during the "test fly assistant" from zero up to 80 percent. It didn't seem to make any difference.

    We then reduced it to zero gain just in case it was gyro induced and it didn't seem to make any difference to the wing rock either.

    We increased the gain to 100 percent and it may have been a slight improvement, but i had to land due to fuel shortly afterward.

    I know the gyro was working because i confirmed that the gain control had an affect before we got airborne, and also in the air when the gain was zero, some trimming was required.

    I know from another thread/ instructions the aircraft should be trimmed first, but this was mimimal.. maybe a couple of clicks of trim on a futaba.

    With the igyro the effect transformed the model.

    The mercury seemed to have little effect.