ZNLine Factory Enigma Build by Mark Novack

There was some space in the day so I started getting some of the sanding out of the way.
We have no special trick for tips. I scribe the center line on the tip, razor plane them until they have a nice basic form and then smooth the planning flats into a nice curved surface. It's a combination of sanding and looking and sanding and looking and, you get the idea. Anyway, nicely rounded tips that are even between the two stab halves. Some people prefer a larger radius, some more narrow radius. I'm not sure if it makes a difference aerodynamically. Here is a photo of the finished tip. Now when I chop off the elevator, the tip will flow smoothly from front to rear.

Another view of the rounded tips.

With the stab socket and incidence pin solid and dry, we can install the stiffening former. It's very light weight balsa with a notch in the top for the antenna tube. It's tricky to get in and glue, but it will never be seen again, so it just needs to be a decent fit and effectively glued. There is not a lot of stress on this piece. We jimmy it into place with various balsa sticks, poking on it from behind and also through the wing saddle opening. It takes about twenty minutes to position it and get the glue where it needs to go. We will not disturb this for a while; we do not want this brace falling over. Important here is that it is a loose fit held into place by the glue. We do not want to distort the fuselage by jamming this thing into a seamless fit. Loose fit, epoxy and microballoon.

Yesterday was more of the same. Sanding, stab mounting, and now the airplanes are almost at the same stage. So, continuing on, today we faced some rudders and closed the tail. I like the tail closing step. It's really easy and is a landmark in the building procedure after all of the little things done inside of the fin. Here is a shot of the fin post. It's about 5-6 grams and is a perfect fit out of the box.

I could not think of anything else that needed to be photographed here. A little epoxy/microballoon mixture and the post is inserted flush with the rear edge of the fin. A small notch at the bottom of the post is made to key it to the tail wheel block. The most important part here is that the fin is clamped flat to the post. Our clamping blocks are very straight pieces of high density particle board that are longer than the fin post. The Burna clamps provide nice gentle, but firm pressure.  This will sit for twenty four hours now. In the mean time we will start elevators and the rudders, keep sanding more tips, and get to the ailerons too.

Another easy step. The rudder is about as simple as it gets. We take our rudder faces and glue them on. We start with the tips, cut them flush and put on the long hinge face. NOTE: If you noticed, we have not installed TE pieces on any of the surfaces. The trailing edge of the ailerons and wing, elevators and rudder will be 1/64th ply. This will make the trailing edge very ding resistant. Here are four rudders that took not long at all. This is not a difficult airplane to build at all.

Well, before we make our hole for the MK elevator device, we shall cut and face, hinge and bevel our elevators, inlay the ply horn mount and attach our horn. This way we can establish the perfect relationship between the horn and the MK device arms. The first thing we do it mark the stabs and elevators as to not get them confused.

We have a fully equipped factory, so we are taking the easy way, but this step is just as easy with a hobby knife and sanding block. When doing five stab sets, this is easier.

We pull back, turn it around and cut the tip.

Don't risk slicing too much. Cut it reasonably close and let your sanding block do the rest.

Do not cut away any of the face. Only the extra tab. The stabs and wings are perfectly routed to accept 7mm facings. Most people will do very well with a sanding block. It takes expert hands to use the belt on on such soft wood.

Here are the two pieces. They are perfectly aligned. JP has been a professional carpenter and wood craftsman for 20 years. His work is second to none.

Another angle.

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