As I got close to finishing the lower wing it became obvious that an important detail of kit engineering had been overlooked. The plans indicate that the entire lower wing center section as well as the innermost rib bay of each lower wing outer panel are to be sheeted with 1/16″ balsa. The usual method of doing this is cutting back, or relieving, the outer edges of all the ribs involved by 1/16″ so that the sheet covering will lie flush with the outer surface of the rest of the wing. None of the ribs in this kit were cut back. It would have been simple to trim each rib before assembly, but I chose to make the fix later in order to illustrate another way of solving the problem.
These are the root (inboard) ribs of the right lower wing panel. You can see where I have marked cut lines representing the correct location of the outer edges of the parts.
Here is the center section with the ribs trimmed back by the requisite 1/16".
This is the center section with the 1/16" sheet in place on the top surface. The kit provided 3" wide sheets for this job, which requires that you make edge joints. Always make those fit as neatly as possible. Any small mismatches can be sanded away later. For larger sheeted surfaces there are other ways to get this right...we'll talk about that another time.
Those plywood spar doublers/dihedral braces that we left protruding from either side of the center section now get to do their job of setting and reinforcing the outer panel joints. The rib space, or BAY, where you see the clamps, will be skinned with more 1/16" balsa sheet...but...I wanted to make the spar to doubler assembly in the open in order get the alignment just right and to clamp the joints securely during glueing.
The lower edges of both wing spars are intended to lie flush with the outer surface (covering). Trimming a primary load bearing structural member like a spar in order to make surface sheeting fit flush is a BAD idea., so we inset the sheet covering as separate pieces between the spars. Here I have assembled the sheet insert between the front spar and the leading edge. The loose piece will go into the center opening.
Hi, I stumbled onto your site via a Great Lakes Goggle search. I have the Flyline kit and was gathering information and photos as backup when I found your build series! Your build sequence was a gold mine for me before attempting this project. I keep looking for your next entry via the goggle images. I do hope that you cover the entire build sequence.
My Dad flew one of these in the 30s so I wanted to build one, only modified to the early 2T with the upright cirrus engine, larger thin wheels, and the small vertical tail. I found an early Cleveland kit plan on ebay and wanted to change the Flyline kit to that configuration. I am retired and getting back into model building as I enjoyed in my youth. Great site : D
Thanks, Bart Hunt Santa Fe, NM
Bart,
Thanks for passing on your experiences. I will, indeed, present the entire build right through (and including) flying. As you will soon notice, I’m going to interrupt the Great Lakes blogs for a bit to talk about the big Stinson SR-9 project, but I’ll be back to it soon.
If you haven’t already done so, please take a minute to check out my new book Hey Mister, Will It Fly? You’ll enjoy it!
Bob
Hey Bart! If you keep an eye on this page it will keep you up-to-date on the latest builds. It says “sorry page not found” but I find it invaluable.
http://www.rcmodel.com/2011/02/building-the-old-flyline-great-lakes-2t-1a-kit-6/
Good day Bob, Is it possible to fill in some of the detail of what happened in the second photo where the front of the ribs disappear from the center section forward of the front spar?
Jim,
Yes. The simple answer is that the center leading edge is cut out (per the plans) to fit the fuselage. Check through some of my later posts and you’ll see lots of detail about how that works. I’m not sure why Hurst Bowers designed it that way, but it’s not a unique approach.
Bob
It looks to me like the lower wing LE was cut back to accommodate the attach point for the rear landing gear struts.
Thayer