David’s STI Build N413KF

[iflywhatevr]

So me the little bit of the fuselage so far has been a lot more fun than messing with ribs!

[efwd]

Unfortunately I think the build manual proceeds as though you are building without upgrades. Being that the fiberglass stuff you will install on the vertical as well as the rudder are all speedster upgrades, things change. Gary has you heading the right direction.

[iflywhatevr]

About three hours today checking the fit of the horizontal stabilizer ribs, sanding, scotchbrite on the frame in the area they would be hysoled to. Cleaned everything up with alcohol let that dry and started with the hysol checking measurements as I went. First thing I realized is that my fat fingers result in anything but a “neat” appearance of the hysol although it got a bit better as I went. I’ve done a lot of painting and caulking in my time which turns out nice but this is a little different working with the angles of the ribs and frame and tight spaces. Cleaned up the excess with a rag with a bit of alcohol on it so it wouldn’t look like a complete disaster but didn’t sweat it too much since my main concern was that the ribs were firmly attached and straight. No one will ever see any of this again after the Oratex is on!

I ordered a 36 inch piece of balsa from Aircraft Spruce yesterday which I plan to use on the stabilizer and elevator wingtips. I’m flying a trip the next couple days so I will let this harden up and then move on to the elevator when I return.




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[Meyer]

Good luck on the build!!

Hopefully you lined up the ribs on the elevator before you glued those down on the HS so that you are sure they will line up with each other. On mine, I measured like the manual said originally but if I had secured them that way the ribs would not have lined up identically with each other between the elevator and HS.

[iflywhatevr]

I did I had to shift the HS ribs in two locations slightly from the book measurements to make sure that they would line up with the elevator ribs and not be blocked by the metal components.

[iflywhatevr]

Well the tip about using model glue to tack the rib first made all the difference in the world. Just a drop on each end of the rib to hold it in place and then went back with a 10ml syringe of hysol to secure all the ribs on the elevator today. Much better looking finish and a lot less hysol used with this method. Once this dries I’m going to hit it with varnish and then move on to forming the tips with the balsa wood I picked up from Aircraft Spruce.


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[iflywhatevr]

Been slow going on the airplane end of the year is always crazy busy for aircraft sales with clients trying to get those last minute tax benefits. But back to work on the project.

In the last week I have formed the elevator and stabilizer tips out of balsa, attached them with structural adhesive, and then once I did some fine tuning of the shape coated them with structural adhesive for strength.

I did a couple test pieces of balsa that I coated with hysol, sanded and then perfected with superfil on top of that to eliminate any imperfections. Even smacked with with a big box end wrench a few times to see it’s resistance to hangar rash and it seems to hold up well so I will finish off the tips with supefil this week when the weather is a bit warmer and I don’t have to run the heat full blast to keep the garage at 70 which is the recommended cure temp for the superfil.

I moved on to pressing the bearings into the horizontal stabilizer and used the method I saw mentioned on here of a bolt with a washer on each end that could be tightened to press in the bearing. I had to sand down the outside of all 7 bearings despite having the holes reamed to the correct size in order for them to fit snugly. No way they would have ever been able to be pressed in without deforming at their original thickness. Found that chucking them in a drill and using some 220 grit sandpaper did a nice job and then I checked with a micrometer that it was a uniform size. Sealed in with the loctite 680 as recommend.

Attached the horizontal stabilizer to the fuselage and worked on the slider blocks which is a cool solution for allowing the stabilizer to be trimmed. Attached the stabilizer struts.

The elevator is currently just hanging from the fuselage I need to do a lot of work on the bushings to attached the elevator to the stabilizer. The one bushing needed to attached the stabilizer to the fuselage took about 30 minutes to chuck in a drill and a lot of trial and error to get just the right fit. Ended up starting with 80 grit sand paper then 220 and finally 400 to give it a smooth finish. The others should be a little faster now that I know what I’m doing but certainly time consuming none of them are very close to their necessary size.

All of the hardware I am just barely threading the nylock nuts on since I know I will need to pull off the stabilizer and elevator to cover the airplane. The slider block hardware is the only thing that has had its final tightening down at this point since it doesn’t need to come off.

Looks a little bit more like an airplane now!


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[iflywhatevr]

Got the electric trim on today and the bushings for the elevator fitted so it could be attached to the fuselage. Trim went together pretty easily other than having to backtrack because I did not ream out the attached point holes ok the stabilizer and the bolts would not fit due to the powder coating. Use of a small pick to sneak the washers in between the various components helped a lot. Onto the fuselage portion of the binder tomorrow!




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[bbs428]

Sure like the black powder coat. Nice work!

Nothing on the plane is really that hard to do but add up every task, some good old head scratching, a few dozen re-read's of the build manual and you end up with your spare time being traded for one of the best flying planes on the planet. Some are more efficient with the time than others... I'm in the latter group.

[iflywhatevr]

Elevator is on after LOTS of sanding on the bushings in order to make them fit they were all very oversized. Moved onto the fuselage portion of the binder starting with the control column and reaming various mounting holes on the fuselage. The tip in the instructions about using a dab of superglue to hold various washers in place so they can be slid into place without fighting with it for hours was key! It made a huge difference moving things along particularly on the rod ends where they connect between the two control sticks where access is very restricted. Had to order a different .1875 reamer off of Amazon that could be used with a t-handle as the access to many of the mounting holes on the fuselage doesn’t allow enough room to use a drill with the reamer designed to be chucked that came with the tool kit from the factory.




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