With most of my projects, I like to start building with the small parts to get warmed up and work my way up. So I start with the tail surfaces and then when they are done, I do the fuselage and then I move to the wing. So with that said, I started getting the fuselage started. Most of Ziroli designs are built around a flat built up crutch that aligns and ties all the formers together.
So as show below, the first thing to do is to layout the top view of the fuselage, cover it with GP Plans Protector and start pinning the longerons, cross-pieces and diagonals into place. If I hadn’t mentioned it in a while, I get my balsa from Balsa USA and I ordered all the material from the Ziroli Builder’s List for all the wood for the plan I am building from. Here you see that the lite-ply wing saddle doublers have also been glued in place.
As shown below, I make up several supports, all the same size and height that are used to lift the crutch up off of the plans.
Once the supports are made, I place them under the crutch and then line up the crutch with the centerline on the plans. I then pin the crutch to the supports and the supports to the workbench.
So carefully and easily slide all the formers into place and adjust the supports to clear the formers. Make sure they are vertical and square to the crutch. The saddle doubler has notches in it that help align the middle formers.
Sight along the tops of the formers and make sure they are correctly positioned. Now tack glue the formers to the crutch.
It is important that the crutch stays parallel to the workbench so you do not build a twist into the fuselage structure. I use lead weights to keep the structure aligned with the supports.
Also make sure that all the cross-pieces are centered with the formers as they provide strength and stiffness.
If there is a little space between the notch in the formers and the crutch longerons, center the former and slide in thin plywood shims to take up the space.
Here you see the space at the former before it has been centered. The former in the background has a ply shim installed.
A unique feature of the Skyraider is that the vertical fin is built and blended into the aft fuselage. Here is the vertical keel piece that ties the fin into the fuselage formers.
Once you have the Keel part in place, you can then add the rest of the formers and internal vertical fin formers as well as the rudder post and rudder hinge support tabs.
Before gluing in these important parts, you should make sure everything is centered and properly aligned with the fuselage centerline.
I check the alignment of the tail and fin by adding a few stringers to the fuselage. Misaligned parts show up right away.
Here you see I have added the stringers to the top half of the fuselage. I will add a few more to the lower aft to make sure the rudder post is aligned.
Once the fin is aligned, you can use the rudder to properly space and align the hinge support tabs. Don’t glue anything until you know everything is in alignment. Once you have the alignment set, use the rudder to help guide the rest of the vertical fin’s construction.
Here with the rudder in place, you see everything is flowing nicely from tail to nose.
Here you see the majority of the stringers have been added and the lite ply wing saddles are in place.
A note here is that you won’t find quality stringer material readily in the local hobby shops. I use a Balsa Stripper from Master Airscrew to make my 1/8 x 1/4 inch stringers.
The rest of the fuselage aft bottom section is joined together with a pair of 3/8 inch square balsa longerons. Once all the glue has dried, use a razor plane and a sanding bar to smooth everything and blend all the stringers flush with the formers.
Thanks it for now, stay tuned for more fuselage construction details and the installation of a scale retractable tailwheel assembly.
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