As soon as the tailplane’s servos fitting-out was done I busied myself with the linkage. To start off with, I made a few errors which had to be corrected. I will describe those errors as well as the solutions, so perhaps somebody can learn from my mistakes.
Since I’m not too sure what forces I will have to account for, I’m erring on the safe side. At any rate, I reproduced the linkage used with the Easy Glider and chose a combination of 1 mm steel rod, 2-to-1 mm and 3-to-2 mm bowden tubes.
Fitting the engine has sent my motivation soaring, so to speak. So I launched myself at fiting the servos.
Alas, I soon realized that my “planless” construction made my life a tad more difficult. In order to soundly fit the servos, the fuselage has to be reinforced and strutted. I had partially anticipated this and thus constructed the belly with very few slats. Nevertheless I’ve come to realize that one’s way better off if the servo mounting’s fixture is built into the fuselage from the get-go.
The cross cut sled is assembled, but not precisely adjusted, yet. This calls for patience and precise work, as I’ve learned from painful experience. In total, I needed six attempts until I was satisfied with the results. However, I am now!
Via Michael Truppe’s video channel “Let’s Bastel” I learned about the fice-cut-test. This was apparently invented by William Ng, who demonstrates and elaborates on the underlying principles it in a youtube video. Truppe summarizes it in german.
By assembling the tailplane the construction is finally finished, so now it’s out-fitting the model. As a matter of fact that’s already started since I fitted the aileron servos while building the upper wing.
I’m going to work my way through the fuselage from nose to tail. So today’s topic is set: the engine has to be fitted.
The easy part was constructing the sled bottom. Now it’s getting straight at the nitty-gritties, namely construction the fences and attaching them.
The front fence needs to be as level as possible, so it can’t just be cut from a single piece of board. Almost any board has some kind of warp which is simply inacceptable for a precise fence. Thus, the front fence has to be comprised of a cornered construction that is self-centering.
As I mentioned in the construction report, I made a mistake while building the vertical stabilizer for my biplane, namely not chafing the trailing edge. Attempting to correct this using the transverse stop thoroughly failed. In order not to have to repeat this experience, I’m building a cross cut sled for the circular table saw.
However, a cross cut sled is capable of many more things. For once it facilitates to repeatively cut slats to length, thus one can skimp on a mitre saw. And then one can use it to get small boards back to right angles which were cut crookedly, so they can be rip cut again. So today is about the first part of a mini project which will facilitate my other handicraft.
Finishing the vertical stabilizer only leaves the tailplane’s assembly. Here, three important objectives have to be met: the horizontal stabilizer must be in parallel to the long axis, so must the vertical stabilizer, and the vertical stabilizer has to be at right angles to the horizontal stabilizer.
The most important contribution to the right angles is provided by clean, perpendicular cuts, which I can achieve easily thanks to my table saw. In order to further stabilize this orientation, I’ve constructed two guides from balsa wood and sanded them into a streamlined shape.
The vertical stabilizer’s guide is in progress.
The structural work is coming to and end: since the horizontal stabilizer has made much progress, it’s the vertical stabilizer’s turn.
Horizontal stabilizer and elevator reinforced.
Horizontal stabilizer and elevator reinforced.Even while building the horizontal stabilizer I realized I made a design error: the thin leading and trailing struts have been glued to the tips as butt joints, lacking adhesion area and thus stability. I rectify this by reinforcing the corners with small wedges of balsa wood. And this enlightment directly flows into the vertical stabilizer.
The landing gear’s completion left only one step to finish the structural work: the tailplane. I copped out for a while to face this step because the tail plane ultimately makes or breaks the aircrafts stearability:
If it’s too small, you can’t control the model aircraft. If it’s too big, the bird responds like a proper boulder. This effect is additionally influenced by the fuselage’s length, as I’ve already mentioned while building the fuselage. That’s why I’m really glad to have found Christian Forrer’s web site, including an excel sheet for calculating model dimensions, before I started constructing my biplane in earnest. Based on the finished parts, I was able to determine the minimum size for the tail plane and get on with it.
Last Saturday, an old friend of mine and I held a small operation session at his place. The weather was fabulous, we had high temperatures for february, around 14°C and lots of sunshine.
It’s been a huge success: multiple trains running simultaneously, shunting, test drives, lots of talk on lots of topics. But most important: a train-load of fun!
This web site uses cookies to support language selection and comment functionality. No other user-related data is tracked.