PIK20 rebuild
Posted: 14 Feb 2019, 15:23
Having designed a set of built-up wings for the PT Pik20, a friend gave me a PIK20 fuselage which had previously been "repaired" after having its tail snapped off. Also, the damaged fin had been split with a razor saw around the original join seam in order to clean up the inside of the fuselage join area.
Whoever had attempted the previous repair had used a shiny blue outer surface carbon? tube, but had apparently used an epoxy or similar glue which was still gooey in places & had certainly not bonded very well to the original polyester glass. I was able to twist out the tube in strips & then clean out the goo/harder stuff fairly easily, cleaning off further using an IPA wetted cloth to get back to clean polyester glass.
The additional external glass epoxied directly onto the top of the original smooth gel coat was easy to peel/pick off!
It also looked as if the fin post had been similarly glued as the hard brownish glue could be sliced/pinged off from the original polyester glass.
There was also an equipment mounting tray fitted in a similar way in the cockpit area. This also pulled off in one piece pretty easily as shown below.
Although I didn't get any photos of the original state, I include a few taken after I had removed the joint tube, finpost, tailplane mount, cockpit tray and as much of the joint material as i could to get back to the original polyester glass surfaces.
Apart from the rear fuselage/fin break, the forward end of the fuselage is pretty much undamaged.
My repair plans are currently:
1. Make a new polyester glass rear fuselage internal support tube, using the outer gel coat surface as a mould. This is then slit to remove from the fuselage and the slit widened to allow it to be compressed enough to slide inside the fuselage break area & be attached with polyester resin.
2. Put a lightweight glass cloth layer on the inside of each fin half to stabilise these before rejoining & then carefully refit to the fuselage over the new tube stub.
3. Once the fin has been correctly reassembled, pick off the gel coat around the joint & apply an external glass bandage before filling as necessary to achieve a smooth finish before repainting the whole fuselage once other minor damage had been repaired.
Hopefully, apart from a little extra weight, it should give a firmly bonded repair. We shall see in due course
Whoever had attempted the previous repair had used a shiny blue outer surface carbon? tube, but had apparently used an epoxy or similar glue which was still gooey in places & had certainly not bonded very well to the original polyester glass. I was able to twist out the tube in strips & then clean out the goo/harder stuff fairly easily, cleaning off further using an IPA wetted cloth to get back to clean polyester glass.
The additional external glass epoxied directly onto the top of the original smooth gel coat was easy to peel/pick off!
It also looked as if the fin post had been similarly glued as the hard brownish glue could be sliced/pinged off from the original polyester glass.
There was also an equipment mounting tray fitted in a similar way in the cockpit area. This also pulled off in one piece pretty easily as shown below.
Although I didn't get any photos of the original state, I include a few taken after I had removed the joint tube, finpost, tailplane mount, cockpit tray and as much of the joint material as i could to get back to the original polyester glass surfaces.
Apart from the rear fuselage/fin break, the forward end of the fuselage is pretty much undamaged.
My repair plans are currently:
1. Make a new polyester glass rear fuselage internal support tube, using the outer gel coat surface as a mould. This is then slit to remove from the fuselage and the slit widened to allow it to be compressed enough to slide inside the fuselage break area & be attached with polyester resin.
2. Put a lightweight glass cloth layer on the inside of each fin half to stabilise these before rejoining & then carefully refit to the fuselage over the new tube stub.
3. Once the fin has been correctly reassembled, pick off the gel coat around the joint & apply an external glass bandage before filling as necessary to achieve a smooth finish before repainting the whole fuselage once other minor damage had been repaired.
Hopefully, apart from a little extra weight, it should give a firmly bonded repair. We shall see in due course