43% Edge 540 ARF Wing Recall/Replacement

[islandflyer2]

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.

[islandflyer2]

UPDATE

PAU 43% Edge 540 Wing Recall Notice

Given the unexpected nature of the recent wing incident, it is taking us a little time to put the solution into action.
The most timely course of action turns out to be going back to the original factory. It would take too long for any one new to start from scratch.
However, this will also require a bit of patience: they need to finish what is already on their work tables, and then will jump right into our work. The best time estimate right now, is that the new foam core wings will be completed within three weeks, and I will have them air freighted to our warehouse.
In addition to the foam core wings, we have ordered a few built up wings that have been redesigned for higher strength, and better glue joints. I have received a few emails specifically requesting these improved built up wings, and we are happy to provide what our customers want, any time that is possible.

A couple of clarifications must be made:

- No customer had a failure, as the wing damage took place on a demo plane. We immediately notified all our 43% Edge customers.
- PAU is paying for these new wings, as we cannot squarely place the blame on the factory: the demo plane that had a failure was flown without any outboard aileron servo; this means that there was no control linkage from the aileron tip to about the middle of the aileron; this makes the infamous flutter highly probable, and we cannot blame the factory for it. We are taking these drastic measures because we do not wish to take chances on your safety.

We thank our customers for their loyal support, and we will keep you posted on the progress.

[cbk07]

Thanks again for the update and great customer service Herve!! Any idea on the weight difference between the original and new wing design?? I like the idea of a foam wing as long as the plane will remain in the 38-39 lb range. If not, then I guess I would like to stay with built up. The main appeal of this plane to me was the weight. Hoping you will be able to keep it in the same ballpark.

As far as a time line, sounds like the wings will be here in March sometime. This is great news as this is the plane I am taking to the Nall this year. Definitely appreciate the quick service!!!! Best wishes,

Craig