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Oct 10, 2021, 03:40 PM
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Looks like excellent craftsmanship. Wood gives that opportunity.
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Oct 10, 2021, 06:56 PM
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Thanks, I am moving right along now with gluing the tail part of the fuse frame together and it all matched up very nicely. I did use a long straight edge and measured off the edge of my steel build board to verify the center line, as the plans printed line was a bit off in a few spots. After marking the center of the fuse formers and all the double checking, I used my mag jigs to line it all up perfectly and then glued the tail together...you only get one chance to get this right or the fuse will be crooked forever...
Oct 11, 2021, 10:36 PM
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The 5/16" square balsa cross-pieces are glued in with Titebond III and drying. I decided to use straight edges held with magnets to get a straight run and then checked square with a steel square while glueing and it looks to have worked well, making sure each pair of cross-bracing was exactly the same to achieve squareness.
Oct 12, 2021, 09:54 AM
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It all came out pretty good, now on to the fun part and will start working on the nose next with motor mounting and such.
Oct 12, 2021, 10:33 AM
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More than close enough! I cannot even measure 1mm. The 1mm difference in the airframe may not even be noticed in flight. It's looking great, especially with the floats in the background.
Oct 14, 2021, 10:38 PM
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I always like mounting the motor and getting the first part of the electric conversion completed. I purchased a Great Planes motor standoff kit GPMG1275 a few months ago for about $40 (everyone is showing discontinued or unavailable now) and it worked great! They give you enough parts to do a few planes and it is made for 50cc Rimfire motors so more than enough strength for the Power 160 motor. I had to drill out and enlarge the holes in the Eflight motor mount to 1/4 to fit the standoff 1/4 bolts but otherwise perfect fitment. I hope that the kit is available in the future again as it is really a nice standoff kit with a few different size aluminum heavy duty tubes and plenty of hardware.
Oct 17, 2021, 01:32 AM
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Working on the nose assembly now.
Oct 17, 2021, 04:33 PM
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Gussets for the fuselage trusses.


After much reading of other builds and looking at Airfields Models website, I decided to make more work for myself and install some gussets on the fuselage cross trusses per recommendations of other builders. The very thin ply that is used (I had some 0.5mm thin ply scrap laying around) and cut out with scissors adds virtually no extra weight but the added strength is enormous. SO, I fabricated 24 gussets and now am in the process of gluing them in with Titebond III, which will take a few days to complete. Luckily it is easy to get in there to install these as normally you would do this when building the trusses.

I also worked on the nose section some more this AM and found out since the nose is tapered you really should sand the mating surfaces, that glue to the fuse, flat so there wont be a gap. The instructions don't mention this and no other builder has mentioned this either, but I am sure everyone that has built this cub knows what to do. I took a large sanding block I made and very carefully sanded the back of the nose flat.
Last edited by nhk750; Oct 17, 2021 at 04:41 PM.
Oct 19, 2021, 08:23 PM
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Alright, got the truss all gusseted up and it is looking good, now I can focus my attention on the nose and get the motor, esc, wiring and front end work all sorted out.
Oct 20, 2021, 07:56 PM
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Installing the nose section


It was kind of strange how they designed the nose section and how it attaches, but I guess it works. I used the magnetic jigs to hold everything in place as the epoxy cures, but I really could not get it clamped very tight. Possibly using large long clamps and clamping from the aft of the fuse cabin section to the front of the nose would work also, but the jigs did clamp it tight enough for a good bond and there are more ways to skin this cat, I would imagine.

I am planning on installing some light ply or balsa sheet on the inside joints with epoxy to reinforce the joining area as others have said this is a weak point for the Sig 1/4 scale cub and a definite must do on the list of modification and improvements during building. I have heard people also fiberglass both the insides after installing the cabin support wires for reinforcement and securement of the wires, but balsa or light ply sheeting works fine too. The outsides will have light ply sheeting installed later.
Oct 22, 2021, 02:20 PM
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Firewall epoxied in place using the mag jigs to hold in place. I will be adding a few diagonal shaped gussets to the inside sides of firewall for some extra strength before everything is boxed in.
Oct 23, 2021, 08:46 PM
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Just a quick update today, got the reinforcements epoxied into the nose, some triangle stock on the sides of the firewall and thin plywood strips along the butt joined seams of the nose to fuse area. It's a good idea to put these reinforcements in as you wont be able to get in there once the structures on the top and bottom are built and that is also why no reinforcements are needed on the top or bottom as they will be very strong with the built up parts being added later.
Oct 25, 2021, 09:52 PM
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Drilled the holes for the cabin wires in F5 and sized to a slot with the Dremel to fit, then cut out the remaining material from the top of the wire slots in the sides of nose with a hacksaw. The cabin wires pretty much positioned on the first dry fit and I just need to tweak the right wire a bit then will be ready to epoxy them in.
Oct 27, 2021, 11:01 AM
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Epoxy the cabin wires


Here I go again, trying to reinvent the wheel...Anyway, I decided to try a better way of epoxying the cabin wires in. I used thin CA and glued some thin balsa sheeting to the insides of the cabin wire slots to seal up the backside of the slots after I dry installed the wires. This also tacked the wires in place so they would not move while I positioned the fuse to apply epoxy. Then, I used epoxy syringes to inject epoxy into the wire slots behind the wires in the bottom and top, then baby sat the fuse and added more epoxy as it sunk into the holes. If I were to do it again I would coat the wires, install them, then glue the balsa sheeting on then inject more glue in, but no matter what you do it is still a bit messy. After this all cures the outside lite ply cheeks will be installed and then you can finish injecting and applying epoxy to the outside slots and exposed wires and seal it all up with the plywood. I would imagine this will be very strong, but I may not have got all the inside wires coated with epoxy because you cant really tell with the balsa sealing up the slots. That's why if this is done it would probably be better to coat the wires first then seal them up on the inside, although I think the way I did it will be plenty strong enough.


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