larrytoelle
05-27-2007, 10:16 AM
Howdy,
First off ... the following is in no way meant to criticise any product, only to inform others of a failure that I've had with a configuration of equipment and setup that I suspect is entirely my fault. This is an older bird with a new Jewel and AP2000i setup.
The following picture is of the bird, equipment and setup that I used.
Notice that I've used a two-tap variety Jewel generator ... the second tap (11.3V) intended for a camera mount. Also, note that this bird has an AP2000i stabilization setup using a FMA I/R sensor.
The first tank, after a thorough, engine running, range test was uneventful ... requiring some trimming due to the AP2000i setup. The Jewel seemed to be operating correctly ... the AP2000i indicated periods of 5.1-5.2V output, a voltmeter to the second tap showed output varying to engine speed. After initial tweeks, the bird flew smoothly and reliably with no sign of a problem.
On the second tank, I began experimenting with the AP2000i, recalibrations and varying gain to the unit. Again, nothing out of the ordinary ... things seemed to be working as I would expect.
On the third tank, at about 75 feet, the bird entered a hard left aileron roll, and continued the roll into the ground after one full roll and a little bit.
I can only speculate at this point, but I suspect the aileron servo went to full deflection and didn't respond further.
During the build, I had debated with myself where to locate the electronics for the Jewel ... finally mounting the first package on the aileron servo. This I suspect contributed to or perhaps was the sole cause of the failure. Although I had range tested and flight tested this setup ... when it failed the aileron was definitely locked in hard over. These are 8311 servos, installed new on this bird ... with perhaps 3 gallons on them.
Although the AP2000i setup is new on this bird and perhaps a contributor, I don't believe it was active at the time ... although I may have nudged the slider to activate it ... can't say for certain. Even if it was active, I can't imagine its normal operation would've caused a hard over aileron.
After the crash, the I/R sensor had disconnected itself and was found in the general line of flight. It's possible that it might have come loose from its mount and caused the problem ... but again ... I believe the AP2000i was inactive at the time ... but not entirely certain. Also, normal stick inputs seem to override AP2000i inputs, so unless the AP2000i simply went nuts, I'd find it difficult to believe the AP2000i was the culprit, or sole culprit.
Unless someone has a better thought ... I suspect mounting the Jewel's package on the aileron servo is the problem.
LT
First off ... the following is in no way meant to criticise any product, only to inform others of a failure that I've had with a configuration of equipment and setup that I suspect is entirely my fault. This is an older bird with a new Jewel and AP2000i setup.
The following picture is of the bird, equipment and setup that I used.
Notice that I've used a two-tap variety Jewel generator ... the second tap (11.3V) intended for a camera mount. Also, note that this bird has an AP2000i stabilization setup using a FMA I/R sensor.
The first tank, after a thorough, engine running, range test was uneventful ... requiring some trimming due to the AP2000i setup. The Jewel seemed to be operating correctly ... the AP2000i indicated periods of 5.1-5.2V output, a voltmeter to the second tap showed output varying to engine speed. After initial tweeks, the bird flew smoothly and reliably with no sign of a problem.
On the second tank, I began experimenting with the AP2000i, recalibrations and varying gain to the unit. Again, nothing out of the ordinary ... things seemed to be working as I would expect.
On the third tank, at about 75 feet, the bird entered a hard left aileron roll, and continued the roll into the ground after one full roll and a little bit.
I can only speculate at this point, but I suspect the aileron servo went to full deflection and didn't respond further.
During the build, I had debated with myself where to locate the electronics for the Jewel ... finally mounting the first package on the aileron servo. This I suspect contributed to or perhaps was the sole cause of the failure. Although I had range tested and flight tested this setup ... when it failed the aileron was definitely locked in hard over. These are 8311 servos, installed new on this bird ... with perhaps 3 gallons on them.
Although the AP2000i setup is new on this bird and perhaps a contributor, I don't believe it was active at the time ... although I may have nudged the slider to activate it ... can't say for certain. Even if it was active, I can't imagine its normal operation would've caused a hard over aileron.
After the crash, the I/R sensor had disconnected itself and was found in the general line of flight. It's possible that it might have come loose from its mount and caused the problem ... but again ... I believe the AP2000i was inactive at the time ... but not entirely certain. Also, normal stick inputs seem to override AP2000i inputs, so unless the AP2000i simply went nuts, I'd find it difficult to believe the AP2000i was the culprit, or sole culprit.
Unless someone has a better thought ... I suspect mounting the Jewel's package on the aileron servo is the problem.
LT