Overview
The cowls supplied with this kit were to suit the 912 Rotax fitted with a ground adjustable propeller. The constant speed propellor selected has a 60 mm prop extension incorporated so it meant the cowl would require modification to fit.
Installation
The first task was to fit the Flying Legends stainless steel prop jig to the Rotax propeller hub creating a fixed reference for the cowl installation at all phases. After installation the correct spacing was calculated [36mm] and the front plate adjusted using the M6 threaded rods separating the two [2] [ plates.
Note: The stainless jigs were cut locally at Laser Wizard from factory supplied DXF files
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| The top cpwl is secured through the 3.2 mm holes laser cut in the plate The advantage is that because of the accuracy any set of holes can be used |
Installation of the top cowl showed it might have enough length if the cut allowance was used but would require modification to remove the hump at the cut line. A steel strip was clamped to the side and the cowl edge trimmed using the factory cut lines with a Dremel cutting tool fitted with a thin cutting disc.
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| Repeated at both sides |
Next the lower cowls were fitted with a gap at both sides and widest at the starboard side. Again a strip fiberglass would have to be added using the cowl side as the former.
The task started with the top cowl by cutting a series of slots using the Dremel along the factory cut line and then cutting a series of perpendicular cuts to allow the area to expand when straightened.
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| Top cowl ready to fiberglass |
A series of aluminium channels were clecoed to the cowl and then clamped to the channels for the perimeter of the cowl. Next a width of 50mm and 75mm fiberglass tape was fitted to the underside using West Systems Epoxy. With the areas fiberglassed the cowl was refitted to the aircraft and allowed to cure.
When this cured all the clamps were removed and the cowl reposition on the aircraft and a series of 50mm / 75mm tape added to the top side of the cowl in two separate applications. Finally the same was done on the underside in the same manner. The cowl was laid on the aircraft for curing at each operation.
The side cowls were covered in packaging tape allowing 3 layers of 75mm wide fiberglass tape to be laminated and allowed to cure.
Once cured they were removed and the sides scuffed and glued to the sides using the West System epoxy and sanded to profile using a orbital sander and 80 grit discs.
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| Check of side cowl before sanding |
Once checked the inside face of the extensions were thickend using layers of 50mm glass tape to match the factory thickness and then capped with a 75 mm wide layer bonded between both for additional security.
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| Final check before starting the installation of the fasteners |
Comment
It worked out even though I had no idea of what or how to do the job.
The new cowls are a total redesign with a lip at the wheel entrance, removable side cheeks with the lower cowl now beign a one piece assembly.
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| Entry lip resist air entering wheel well |
Joys of the early purchaser
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