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| Factory repair scheme |
On return from AUSFly 2015 the fuselage was unloaded from the return trip with all seemingly OK until the fabric strap used to hold the fuselage at the rear was removed and the damage to rib 9 and the port skin was uncovered. Without the boring detail the rear was located at the rear of the trailer for the return trip and it can be concluded at the additional acceleration collapsed the rear support allowing the rib to ride on a hold down strip and the rest is history.
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| Happy Days at AusFly |
The factory was contacted and the repair scheme above was received within 48 hours and the parts were manufactured, alodined and dispatched with the supercharger upgrade kit.
While this was inconvenient and not a task I would willing seek out, it was one of the reasons I chose to build a conventional aluminium factory kit.
It can be repaired in the field with basic tools and should be part of any builder selection criteria. While it may grant bragging rights to have a kit built using the latest honeycomb graphite composite remember that you have to maintain it - a point to consider
The Repair
Rib No 9 was a total loss and Rib 8 had a couple of small creases and it was decided to remove it on spec. Once removed the longitudinal channel was straightened as much as possible and the new channel slipped over it and match drilled and clecoed.
Next the damaged rib was cut out using aviation snips and trimmed back to the underside of the longeron leaving the existing attachment brackets in-tack. The scrap for the No 8 rib was used as a drilling jig for the lower attachment but the damage to the No 9 rib precluded this approach.The new rib was trial fitted and aligned to the channel doubler. When satisfied the first mounting hole for the No 9 rib was drilled - re fitted and all other holes match drilled. This was repeated for the other side then the flange's at the center tab.
Next the No 8 rib was installed using the pre-drilled mounting holes as the starting point then all other holes were match drilled.
The channel was now reinforced with a length of aluminum angle and the tabs to attach the rib to the channel were pre-drilled to mount to the rib's, then the assembly match drilled. A single counter sunk 3 mm rivet was installed to secure the assembly. This operation was repeated at the next rib.
The sides were match drilled into the rib flange on each rib and cleoced. All bulkheads were fully riveted using 3 mm x 8 pop rivets at each attachment point including two rivets into the flanges.
The next task was to fit the undamaged skin on the starboard side to check alignment. This was slipped under the side skin and wrapped around using the two remaining drilled rivets to meet the lower channel.
A number of the other ribs had holes drilled using the skin to assist in this task. The lower flange is highly mobile and this resulted in the rivets location 2 - 4 mm from the flange of the rib and I suspect that they were not exactly in the correct alignment but in the case of the No 9 rib it had little give at this point so the alignment had been set at assembly
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| Repaired No 9 Rib |
The factory supplied two new skin's and one was placed on a flat table laying on 6 mm aluminium foil insulation that proved perfect for this task by allowing the drill to clear the skin and the cleco to bite at the hole created in the foam insulation effectively locking the job as the cleco's were added.The damaged skin was cut to allow it to lay flat with weight applied and the holes traced around the sheet.
The holes for the connection at the channel will be matched drilled at installation
Next working week we close the rear to allow the tail to be fitted.
To at least make me feel better when the liquid level was checked on the tail plane, it was perfectly level with the fuselage - all well that ends well.
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| Back were it all started |
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