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Islandflyer · 02-28-2008, 01:30 AM

PAU 43% Edge 540 Wing Recall Notice

Following a wing failure yesterday (Saturday), we at PAU have decided to recall the wings of the 43% Edge 540 ARF, and a few customers were already notified by telephone. This costly decision was made as proactive measure in response to one single incident that happened on one of our demo plane.

Just to put thing into perspective:
- Demo plane #1 has more than one hundred flights with no incident, and is still going strong.
-Demo plane #2 had this problem in its eleventh flight. Upon close inspection, the glue is what failed, rather than a lack of glue as we first feared.

Unfortunately, this demo plane (#2) was not set up as prescribed with 3 aileron servos per side and 2 elevator servos per side. Instead, it was set up with 2 aileron servos per side, and 1 elevator servo per side. Therefore we will never know if the failure was inherent to the construction, or due to the number anchor points on the ailerons that was reduced to 2 per side.
Indeed, we at PAU at well aware that the torque of today’s Ultra Torque servos can move the large ailerons. However, the question is the flex in the ailerons this size: if only 2 servos are used, there could be enough flex to allow some flutter. This is a possible reason for glue failure in wings, as even 1 second of un-noticed flutter is enough to rattle wing components loose. Once some components have come unglued, the integrity of the whole wing is jeopardized.

In any case, even tough we unfortunately will never know the definitive answer as to the cause of the failure, PAU is contacting the customers who bought the 43% Edge 540 ARF to notify them of the decision to recall the wings. We are working on a plan that will allow the speediest replacement of the wings: one likely solution is going to be a replacement of the built up wings with foam core wings. We are looking at the possibilities of manufacturing these foam core wings in the US, in spite of the high costs involved, in order to best serve our customers with the shortest possible delays.

We apologize to our customers for the inconvenience. This failure happened yesterday, and today we are already hard at work to find the best solution. We also urge every one to follow our recommendations: DO use high 3 high quality servos per wing, and 2 high quality servos per elevator.

I will follow up with each of you as soon as we determine the best course of action.

Several of the 36% Edge has been flown very hard for the past several weeks, and has had no issue: hard walls, blenders and parachutes.

02-28-2008, 01:30 AM	#1
Islandflyer Bad-ass Super Contributer! Join Date: Mar 2007 Location: Hawaii Posts: 638	43% Edge 540 ARF Wing Recall/Replacement PAU 43% Edge 540 Wing Recall Notice Following a wing failure yesterday (Saturday), we at PAU have decided to recall the wings of the 43% Edge 540 ARF, and a few customers were already notified by telephone. This costly decision was made as proactive measure in response to one single incident that happened on one of our demo plane. Just to put thing into perspective: - Demo plane #1 has more than one hundred flights with no incident, and is still going strong. -Demo plane #2 had this problem in its eleventh flight. Upon close inspection, the glue is what failed, rather than a lack of glue as we first feared. Unfortunately, this demo plane (#2) was not set up as prescribed with 3 aileron servos per side and 2 elevator servos per side. Instead, it was set up with 2 aileron servos per side, and 1 elevator servo per side. Therefore we will never know if the failure was inherent to the construction, or due to the number anchor points on the ailerons that was reduced to 2 per side. Indeed, we at PAU at well aware that the torque of today’s Ultra Torque servos can move the large ailerons. However, the question is the flex in the ailerons this size: if only 2 servos are used, there could be enough flex to allow some flutter. This is a possible reason for glue failure in wings, as even 1 second of un-noticed flutter is enough to rattle wing components loose. Once some components have come unglued, the integrity of the whole wing is jeopardized. In any case, even tough we unfortunately will never know the definitive answer as to the cause of the failure, PAU is contacting the customers who bought the 43% Edge 540 ARF to notify them of the decision to recall the wings. We are working on a plan that will allow the speediest replacement of the wings: one likely solution is going to be a replacement of the built up wings with foam core wings. We are looking at the possibilities of manufacturing these foam core wings in the US, in spite of the high costs involved, in order to best serve our customers with the shortest possible delays. We apologize to our customers for the inconvenience. This failure happened yesterday, and today we are already hard at work to find the best solution. We also urge every one to follow our recommendations: DO use high 3 high quality servos per wing, and 2 high quality servos per elevator. I will follow up with each of you as soon as we determine the best course of action. Several of the 36% Edge has been flown very hard for the past several weeks, and has had no issue: hard walls, blenders and parachutes. __________________ Herve Lejeune http://www.flypau.com/ http://www.handibond.com/ Last edited by Islandflyer; 02-28-2008 at 02:20 AM.