C4X
Jan 30, 2009, 09:37 PM
This is my first ever balsa project! Recently, I made a few laminated paper gliders, replete with airfoil, which worked surprisingly well. Obviously, I found them to be a little less than durable, and could only achieve decent performance down hill (they crumple if thrown hard). They tended to work nicely until the moisture made them lose shape and performance, but thankfully they stoked me to the point of no return! I needed a real glider. . . .
I built my 1934 Competition HLG from plans (http://www.theplanpage.com/How%20To%20Articles/Fundamentals%20of%20Model%20Airplane%20Building/Part%203/Part%203.htm).
It was originally from the pages of "Universal Model Airplane News". I utilized whatever wood I could find, which in the end is decent enough, but probably a little heavier than optimal (c of g is fairly aft). The model (see plans) is all balsa, 1/4" fuse, 1/8" flat bottom 2 piece sweptback wing with 2 1/4" dihedral, and 1/16" tail feathers. As this was my first build, my journey began with lots of research and plenty of un-answered questions which I had to figure out for myself. That is what it's all about, right? All in all it has turned out fairly well.
The fuse was quite straightforward for a first build, laid out on paper partially with the aid of 1/4"sq graph paper, traced on to the wood with carbon paper, rough cut, sand papered to shape. Because I knew nothing of the details involved prior to beginning this project, the coarsest paper I used was 280, so I added some extra work there. Towards the end of the outline shaping I realized that maybe somehow this could all be easier? Again, more research on the matter. I decided to go with a "Stanley 12-101" micro plane for the remainder of the build, which was only airfoil shaping at this point. I love the little Stanley. I think I'm a plane man now. Probably won't need much more than 280 from here on in, we shall see.
The tail feathers were no problem tracing, cutting and shaping. Nothing to report on that front.
The wing was a little more challenging for me, lots of variables to which I knew not how to react. I can say that I was amazed how my less than perfect traced outline of the wing shapes magically turned out nicely curved and symmetric to each other. Makes sense in retrospect as the shaping process through sanding will generally turn out nothing less than smooth lines, as opposed to right angles and the like, from pencils and razor blades. The profiling of the airfoil was a complete unknown to me as I began in earnest beyond the "make or break" point. As a pilot by profession, I know first hand how critical airfoil shape can be when it comes to functioning within design parameters. It doesn't take much ice on a Caravan wing or a King-Air's laminar flow wing, to increase stall speed exponentially. For my glider's wing, I did some more reading. It was at this point that I made a run to the local hardware store for Stanley (my new little pal ;) ). As per advice from the experts, I marked the mid chord (or high point) and masked it, then began planing. As I worked, I checked the general shape with a template I made from the plans. I sanded between runs with the plane, and re-checked everything. On the second wing half, I constantly checked it's shape against the first. Eventually, they both actually turned out well. To achieve the required 2 1/4" dihedral, I made a little 4 1/2" high stand for the wingtip to rest on while I glued the two halves together. I had intended to use some liquid cement for the glue party, but ended up using thin CA and kicker (because I'm too impatient to wait for glue to dry). Wings were now sorted, Fuse - sorted, Tailfeathers - sorted. Time to put it all together :)
For the wing to seat nicely I had to work a groove into the wing seat on the top of the fuse. That was a hack job at best, but I achieved a good enough result, so no worries. Any ideas for the next one? I continued to use thin CA and kicker, everything glued up nice and square (in future builds, I will def use some Med CA though). So far so good. Check the pics, and look to "Part 2" for the slight hiccup which threatened to destroy my beautiful balsa creation's carefully sculpted lines and its performance potential. . .
I built my 1934 Competition HLG from plans (http://www.theplanpage.com/How%20To%20Articles/Fundamentals%20of%20Model%20Airplane%20Building/Part%203/Part%203.htm).
It was originally from the pages of "Universal Model Airplane News". I utilized whatever wood I could find, which in the end is decent enough, but probably a little heavier than optimal (c of g is fairly aft). The model (see plans) is all balsa, 1/4" fuse, 1/8" flat bottom 2 piece sweptback wing with 2 1/4" dihedral, and 1/16" tail feathers. As this was my first build, my journey began with lots of research and plenty of un-answered questions which I had to figure out for myself. That is what it's all about, right? All in all it has turned out fairly well.
The fuse was quite straightforward for a first build, laid out on paper partially with the aid of 1/4"sq graph paper, traced on to the wood with carbon paper, rough cut, sand papered to shape. Because I knew nothing of the details involved prior to beginning this project, the coarsest paper I used was 280, so I added some extra work there. Towards the end of the outline shaping I realized that maybe somehow this could all be easier? Again, more research on the matter. I decided to go with a "Stanley 12-101" micro plane for the remainder of the build, which was only airfoil shaping at this point. I love the little Stanley. I think I'm a plane man now. Probably won't need much more than 280 from here on in, we shall see.
The tail feathers were no problem tracing, cutting and shaping. Nothing to report on that front.
The wing was a little more challenging for me, lots of variables to which I knew not how to react. I can say that I was amazed how my less than perfect traced outline of the wing shapes magically turned out nicely curved and symmetric to each other. Makes sense in retrospect as the shaping process through sanding will generally turn out nothing less than smooth lines, as opposed to right angles and the like, from pencils and razor blades. The profiling of the airfoil was a complete unknown to me as I began in earnest beyond the "make or break" point. As a pilot by profession, I know first hand how critical airfoil shape can be when it comes to functioning within design parameters. It doesn't take much ice on a Caravan wing or a King-Air's laminar flow wing, to increase stall speed exponentially. For my glider's wing, I did some more reading. It was at this point that I made a run to the local hardware store for Stanley (my new little pal ;) ). As per advice from the experts, I marked the mid chord (or high point) and masked it, then began planing. As I worked, I checked the general shape with a template I made from the plans. I sanded between runs with the plane, and re-checked everything. On the second wing half, I constantly checked it's shape against the first. Eventually, they both actually turned out well. To achieve the required 2 1/4" dihedral, I made a little 4 1/2" high stand for the wingtip to rest on while I glued the two halves together. I had intended to use some liquid cement for the glue party, but ended up using thin CA and kicker (because I'm too impatient to wait for glue to dry). Wings were now sorted, Fuse - sorted, Tailfeathers - sorted. Time to put it all together :)
For the wing to seat nicely I had to work a groove into the wing seat on the top of the fuse. That was a hack job at best, but I achieved a good enough result, so no worries. Any ideas for the next one? I continued to use thin CA and kicker, everything glued up nice and square (in future builds, I will def use some Med CA though). So far so good. Check the pics, and look to "Part 2" for the slight hiccup which threatened to destroy my beautiful balsa creation's carefully sculpted lines and its performance potential. . .