Over the last several years I have devised a method of building box fuselages from stick balsa by lifting up the longerons when building a side frame, then placing a strip of balsa under them for marking and cutting the uprights, together with some tools to do the job.

The typical way people build is to place the upright strip over the longerons, and by sighting down or eyeballing, try to obtain the correct angles and length. That requires quite a bit of skill and time. My approach is far easier and faster. It works great for diagonal spacers and Warren truss type of structures with all the angled cuts, as well as for cross pieces.

The method described here deals with 3/32″ and 1/8″ square balsa strip, with some changes when using smaller and larger sizes of balsa(more on this later). A favorite model, the Miss Canada Sr., is used to illustrate the system. As a side note, the method has been found to be a great help to a fellow modeler handicapped by a stroke.

The tools for cutting spacers are very simple to make. There are two types of cutters, but at this point the discussion centers on what I call a MARKER/CUTTER because it is a double-ended tool in which one end is used to mark where the cut goes, and the other end of the tool, the cutter, finishes the job. The tool is made by sandwiching a short (3/8″) length of razor blade between two popsicle sticks having both ends squared off. Cut a 5/32″ deep x 1/4″ wide U-shaped opening in one end and square off the inside corners, then glue a piece of blade to the other end to serve as a marker. The blade should project from both ends no more than 1/32″. I use popsicle sticks because they are readily available and are a convenient size (1/16″ x 3/8″ x 4-1/2″).

Use epoxy for gluing the sticks together and contact cement for the marker blade. This arrangement gives a very rigid support for the blade, even the narrowest ones I use which are 1/4″ wide. The long “handle” helps a lot in keeping the tool close to the vertical for nice square cuts. I use blades from our local Dollar Store and some double edged blades. I will leave it to the reader to work with what he has available. Better quality blades should give better results but the tool works beautifully to ensure accurate cuts on the first try, thus speeding the work along greatly. A second item that is required is a set of jig/building blocks as can be seen in the photos . These are made from a strip of hard 1/4″(16 lb.) square balsa cut into blocks 1/2″ long with one end sanded to 90 degrees and the other end cut to about 30 degrees. They could be made of pine or some similar wood.

Drill pilot holes about one third of the way from the square end to receive the pins which should be a tight fit in the hole. Make about 30-40 of these blocks which will be used mainly on the outside edges of the longerons. The pins remain in the blocks permanently. This size block can be used for both the 3/32″ and 1/8″ strips. A Pin Driver is next, make this from a 4-5 inch length of 1/4″ diameter hardwood dowel with a 1/8″ diameter hole drilled into each end. The depth of the holes is such that the straight pins do not penetrate my gypsum wallboard building board and ruin the kitchen table(ouch!). A last item that is needed is an end-grain chopping block, again hard balsa or pine, onto which the strip is placed for cutting after it has been marked. The two faces of the block have to be parallel of course and sanded smooth. Always use the end-grain block as this will give a cleaner cut as well as prolong the life of the blades.

Paint/colour all these tools (though not the faces of the block) with a bright colour so that they will be easy to spot among the clutter. This may seem like a long preamble but the tools just described will be available for future building jobs. It would be useful, nay, necessary, to provide for some type of container to hold the knives and blocks (mine were purchased at the same $ Store).

Compared to the standard way of placing the upright strip over the longerons, this new way is actually fun. Protect the plan in your usual way to prevent the structure from sticking to it. Lay down the longerons by placing the blocks for the top longeron in line with the upright positions. For the bottom longeron, place the blocks about 1/4″ off to the side of the upright positions so as to allow free passage of the upright strip under the longeron and to leave room for the marker. Glue up the several pieces of the top longeron if it is made up of more than one piece such as for a cabin model. For the inside edges of the longerons a pin at every second station might suffice.

A word here on how to hold the tool… I find that holding it at a point about one third up from the bottom end gives a good control in keeping the tool vertical as well as making it easier to apply a slicing motion when needed for harder strips. OK, so we are ready to start. Insert a strip of balsa under the bottom longeron, then under the upper one. Line it up on the upright position and gently push blade side of the marker up against the top longeron to mark the angle at that end. At this point it would be a good idea to put a mark of some sort on the piece to ensure its proper orientation later – a “<” pointing towards the front is what I do.

Remove the strip and place it on the block for cutting with the other end of the tool. Re-insert the strip under the bottom longeron and slide it up against the top longeron which by this time has been lowered back down onto the plan. Push the strip up fairly tight against the top longeron and proceed to mark the lower end of that upright. Experience will tell you how much pressure is right. Remove, cut, and, voilà, one very neat fitting upright.

The angles and length are perfect! You really have to work hard to get a reject. The speed of this method and the high degree of accuracy is miles ahead of the old ways. After one side is built, remove it from the building board, but leave the blocks in place to build the second side. With the jig blocks in place it should not at all be difficult getting the two sides the same. A little care is necessary, but then again, we always do use a little care, don’t we?

The business of cutting diagonal cross pieces is handled in the same manner. Since we need the top view of the plan to cut the cross pieces, I draw a basic copy of that onto a strip of paper and staple it a few inches above the top view of the actual plan. The assembly of the side frames is done over this drawing using poster board triangles about 5″ high x 3″ at the base to keep the frames in line and square. An extension at the base is bent over to a 90 degree angle to allow stapling the triangles to the building board. For a typical model of, say, 36″ span, eight to ten of these triangles are needed. As each pair of cross pieces is cut mark them with an arrow as before. When gluing in place put the arrow marks towards the in- side of the fuselage.

For smaller models using 1/16″ square such as Peanuts, life is even simpler: The tool, if one can dare call it that, is simply a short length of razor blade glued onto the side of a popsicle stick. Narrow the end of this tool to 1/4″ wide to accommodate tighter inside curves on small models. Leave no more than 5/64″ projecting from the end and glue it on using contact cement. A neat way to measure this is to push the cutting edge of the blade through a scrap of the chosen longeron material with about 1/64″ projecting. This simple device will be used to cut the uprights and cross-pieces while the strip is still under the longerons. For 3/16″ and 1/4″ wood on larger model the type of marker/cutter described at the outset is made bigger, eg, two strips of 1/16″ ply or pine, 3/4″ x 5″ long, with a 1/2″ wide opening, just over 1/4″ deep. Jig blocks 1/2″ square could do for these two sizes of strip.

So, there it is. It is not an automatic thing, but after you get the feel of using these tools – and this will come quickly – you will be surprised at the beauty of it. Anyone having questions or suggestions can reach me at harrier@nb.sympatico.ca, or at, Marcel Lavoie, 111Victoria Street, Campbellton, N.B. Canada, E3N 1J6

-by Marcel Lavoie

Here’s a procedure for making box frames that Tony Peters showed me when I was just starting out in this hobby. I think it’s the easiest and most accurate way I know, and requires no fancy tooling at all. As with any technique in this tradition, I’ve added a bit here and there, and I also will bring in comments and tips from friends who’ve added to the craft.

For anyone doing this for the first time, the best basic text for learning this stuff is a series Bill Warner did in Model Builder magazine, titled “Hey Kid!–Ya wanna Build a Model Airplane??” This series started with the basics of flight and learning how to “see” what a model is doing and how to deal with it, and works you through progressively more complex models and construction procedures that get you ready for anything you might want to try from there. It’s a great source. Dennis Norman sells a ring bound reprint, by permission, of the entire series. Email him for details.

In this first image you see several things. First and shiniest, the one tool I need to do all my chopping, scarfing, fitting and trimming: one single-edge razor blade, unadorned. You can chop straight through just about all you need with this, with a bit of practice, and save your ExActo blades for later. You learn quickly to cut vertically through your stick (or pair of sticks, as you’ll see) by leaning the blade just barely into the cut, so the knife-edge bevel doesn’t push outward against the wood. Also, pushing the razor sideways in a short slicing motion is way better and easier than straight down. Practice a little on bare sticks first; you pick up the skills fast.

LARRY MARSHALL: “So many modelers believe that a #11 blade can substitute for any other cutting device. As you’ve indicated, when building with sticks, you NEED single-edged blades, which don’t crush the stick ends and can facilitate obtaining square cuts. They are NOT optional or some affectation of us old guys building model airplanes.” To expand on Larry’s comment: a nice #11 blade looks sharp, pointy, and efficient, but you need a long flat surface to sight down when cutting square. Save your #11 for slicing curves in sheet, and even then, leave stock for sanding.

The second thing I want to mention: I’m doing both left and right sides of the box here at one time, with no Saran wrap, no worry about gluing together, no nothing. Why? Because it’s half the time that way, and more importantly, it’s lots more accurate. I start by pinning the pair of top longerons to the line with side-by-side pins holding the longerons snugly. Then, I’ll cut pairs of uprights, a little long, and glue them wherever they go. I’ll put the bottom longeron in later, and you’ll see why then. All the bits of wood that go against the top longeron–the uprights, any gussets like you see here at the sternpost, the scarffed piece that will form the stabilizer slot–all are glued in now, while I have room to work. You see the pin at the bottom of the too-long uprights, pushing them against the longeron for the glue to dry. This takes maybe fifteen minutes in aliphatic glue, less with Duco; so you’ll go from one end of the fuselage to the other in that time, then go back and remove the pins for the next step.

But not yet, there’s one more thing I want you to look at here. I’m holding sticks taped together to make sure the wood I want is all matched up. Store-bought sawn strips are never quite perfect in dimension, and they’re all different stiffness and weight. I use a gram scale to grade all the strips I have, then decide if the lightest ones will be stiff enough by bending them in both directions, selecting the stiffest (You’ll notice those with straight, long grain are stiffer than ones where you see diagonal grain running through the stick on one side). Now, those stiff long ones are paired up for longerons, and the less-stiff ones can be used for the short bits (within limits: no punky wood, anywhere. You decide.). The taped-together part is so I can work with TWO bits of upright at a time, without having to fumble with them.

Here’s the sternpost after the pins are removed. Everything hangs down well past the inner edge of the bottom longeron, and you see the little gusset bits glued to the upright, also long: so that when I trim the bottom line, that joint will be perfect and I won’t have to fiddle with tiny angle bits, which sometimes can be a tricky angle indeed.

Now here’s the bottom longeron in place. See where the diagonal braces (which can be even lighter wood, as they’re all compression, and anything that will break them is more than the model will like anyway!) have been fit a little long, and they have been trimmed too when the cut was made; now they form part of the glue joint as well. The corners against the top longeron and uprights were beveled too, but I had room to work then, remember?

Joints are critical. The closer we get our sticks to fit, the better the airframe will be. Filling glue between balsa does not give a great joint. It’s one reason I like cutting and trimming the sticks I use in the ways I do, it gets me joints that line up & fit in a pretty easy way. Also, I can spread out the joint over a longer area, when I cut my diagonals and uprights in one pass like you’ve seen here; if I had to make that four-bevel cut on each diagonal and get the lengths right before dropping it in, I’d go crazy.

The best thing to me about doing things this way is that I can’t cut anything too short, ever. There’s no fiddling around trying to fit exactly between top & bottom longerons, or do any of the other fiddly bits need anything fancy at all.

With a frame like I’m making here, there’s not so much stress to that gentle curve of the bottom longeron, and the diagonal braces will keep the curvy part from moving when it’s freed up. But you do want to consider those stresses, and in your own box frames you may add a brace or two in areas you might be worried about. Don’t be afraid to depart from the draftsman’s drawing, that’s how you come to find your own way of doing things.

With stressed structures, a lot of us will give the frame a soak of water (usually mixed with ammonia, or Windex, to cut down the surface tension of the water and get it to seep in better), to relax the wood a little. Ammonia will loosen white-glue or aliphatic joints, while Windex doesn’t so quickly. Acetate- nitrate glues like Duco or Ambroid won’t be affected.

Suggested by ART HOLTZMAN: “Many frames have pronounced curves at the chin, like from the nose block to the landing gear. When I encounter these, I carefully slice the longeron in half (1/16 sq into two 1/32×1/16) from the LG forward, wet-form the curve on a mold, and run some glue down the split to bond it together again. Once dry, lay it on the plan and keep on building.”

I’ll let this dry overnight then I’ll take out the pins and sand the top of the double frame while it’s still sticking to the wax paper, just a gentle sanding to bring down any high spots.

Speaking of wax paper, another neat trick comes from DAVE MITCHELL: tack everything to your board using Artists’ Spray Mount repositionable adhesive, available in rattlecans at art and craft outlets. Put the plan down to the board with it, stick wax paper over that, and you’ll have a smooth flat surface that doesn’t bunch or wrinkle under your work. Better yet, this sanding procedure can be done with incredible ease when all’s tacked down and the frame is hanging to the wax paper.

Now to the cutting-apart. The only places the box sides stick together are at the glued joints. You can slip a razor between the sticks at any other place, and push toward the joined spot and it’ll cut/crack loose. Takes about five minutes to do the whole thing.

A very important thing first, when you are ready to separate the sides, mark an “X” on the front or back of the whole frame to remind yourself which are the OUT-sides. You’ll need this little nicety just once, but it’s a big once.

You MUST control your blade–if your hands are not in contact with each other, your big arm muscles will push the blade right through the frame. Keep the frame in one hand and the blade in the other, and press two fingers together as a rest-stop. This allows fine motions with great force. Once in thirty slices, you’ll go a little crooked and start cutting an upright. Back off and get back in line, and glue the upright when all’s loose.

Any sideways slice will ease the force of the cut. Prove this by pushing a sharp knife straight down on a tomato. Look at how deep you can go with a single-edge blade; you can cut most everything you build apart from the outer edges of the frame. Cabin models with elaborate window glazing may be deeper, but the sticks usually flex enough that you can start to bury the backside reinforcement on the blade between the sticks and get down there. Sure, you could break out the blade from its backing, glue it to a handle or not, use a different blade (typically thicker, not a good thing), but I’m preaching the simplicity of using these blades, unadorned, for a very good reason: you don’t want to become too fond of them. If you spend time making up something special, you don’t want to go through re-making, so you try to stretch more much work out of something that is going to get dull. Sharper would be better. When a blade even hints at getting hard to push, throw it out and unwrap a new one!

Now we start to frame out in three dimensions. I’ll talk a little about building straight boxes. We worry over how to guard against “banana” boxes; those frames that seem to fishtail off to the left or right when seen from above. Well, work carefully. -Great, thanks, Michael…but that’s really all, and still there’ll be that time when the frame goes off. Like everything you do with such a vague material as balsa, stuff happens. Learn to enjoy it. My best advice, build over a centerline and work one station at a time. Use as many blocks, jacks, squares, what-have-you as you need, it’ll work out. There are a few specific things you can do as you build, though, and now we’ll look at some.

First, and I didn’t talk much about this earlier, try to pick your longeron sticks to be about the same stiffness. I weighed my lumber and picked a dozen nice ones, and I did mention examining them for straight grain (which helps in the stiffness part), but also you can actually try to match for stiffness in the two directions, either trying to gage this by bending in your fingers or by making up a bending fixture with weights and a protractor. I won’t go into it here, as I think it’s too much to think about right now, but some dedicated guys will go that route.

Larry Marshall’s take on this: “Personally, I would never build with pre-cut sticks as I’m too darn lazy to start sticking them on flex meters and such. But as I create them with a wood stripper, I will create pairs of sticks, cut right next to one another off a sheet and these serve as my longerons. This ensures the same amount of flex that you describe.”

Now, start to box up. I will do two stations at the first glue-up and no more (if I’m smart, and I’m not always smart), and get the resultant box right and solidly dry before continuing. What you see here is all I did for one evening, and then I let it set up thoroughly. Continuing down the frame from here, you’ll have the advantage of an already-dry, solid, integral structure you can count on.

So let’s see what’s in this picture. These two stations are the only square ones in this trapezoidal-box frame, so they’re good as starters. When I cut the cross sticks for the stations I also cut squaring pieces of scrap sheet, a neat trick I got from ART HOLTZMAN–these get taped in and hold the box nice and perpendicular. The great thing is you can cut them for the trapezoid sections in just the same way.

As this is the first pin-down and because part of this particular box bends out of the straight line, I hung the frame off the end of my board. After this I will glue up all the rest over a reference centerline, carefully measuring everything I do to make sure I’m not banana-ing the box–but for now, all I needed was a square drawn on the board to line everything up to for this glue-up; that’s the red lines you see here. One side, the near one, gets pinned down along the reference line, the bottom cross sticks glued up and placed in their positions, the opposite side brought up and pinned down. Then the squaring pieces are put in with lo-tack tape, top cross sticks glued in, and as a precaution I spread rubber bands over the whole thing. (Those are little dental bands, looped together with a lark’s head knot, to make up the length I want. Handy and quick.) I’m building with aliphatic glue, which has a little more working time than Duco, but that’s doable too; and you could set up the whole frame you see here and run drops of CyA to assemble, too, if you do that sort of thing.

Once dry I’ll pull this off the board and glue up fore&aft of this. One more banana-busting tip, and you’ll see it in this next sequence: do the low-stress end of the box first: usually heading toward the tail. Then tackle the hard end.

DICK FORS: “When assembling both sides of a box frame, as in the process of building a square section, once I’m certain a section is square, I like to glue in a temporary diagonal brace. Sometimes, several of them in different sections as I go along. Adds lots of strength until the frame is complete!”

Earlier, I told about stress-relieving with Windex, but there’s something more important to try to do: don’t have any stresses in the individual bits of wood that make up the frame! This is a guitar-maker’s trick, and they have good reason to have no tension in their structures–here, it just means we have less ready to break off at the wrong moment.

I will pre-roll a curve into a stick that bends, just laying it on the board and pulling it under one pressing finger until it takes the shape of the curve I need. Harder bends, I’ll soak and pin up overnight, or soak and then pop in a 250-degree oven for an hour. I didn’t need that here for this frame, but keep the technique in mind. It’s harder to pre-bend the sides to curve into the nose of the box. Bending a whole side frame-nope, better to soak with Windex and gently pull in with pins, squares and rubber bands.

Not all box frames are square-section. You’ll often need to make trapezoidal boxes, both when unadorned as in a boxy-shape model or with formers hung over the box-which is where this method really comes into its own as you can bend the box around to fill out the most space with the least wood. This will be shown in detail in the next installment of this tutorial. In the picture below, you see my cheep and durty method of cutting cross sticks for trapezoid sections.

Ignore the lines on my drawing here. I blew it up, and the wood sizes as shown are now way over what I’m using, so I can’t just go slicing my crosspieces off the section views. So, to get the right size, I’m holding two sticks of my model’s size in my right hand lined up with the outside edge of the section; I’m pushing the crosspiece against the inside edge of those sticks, and cutting the piece along the outside line on the other side of the section. See? [Section] minus [two sticks] equals [space between sticks on each side]. Jeez, I hope that’s clear.

Now comes the gluing of the sections. I’ve drawn a centerline on my board, willy-nilly and in no place, just to line the frame up with. The box frame is laying curved-side down and I’ve pinned the last square section down, centered, there out of the picture. You can just see a little black hatch mark on the crosspieces, right in the middle of their length–they tell me which side is up as well as where they should go on the board centerline. I glue the bottom one and pin the sides against it, then pry open the top and glue the top crosspiece in, and run my rubber bands over the whole section for tension. I’m holding my scale on end as a quick square-check, and if the mark on the crosspiece is out any amount, I can pull the pin with the rubber band out on that side and pull the section back into place that way. It’s a very easy and, once you get used to the risk and just trust yourself to do it right, a surprisingly accurate way to get things lined up.

Here’s the end of the frame. Two things I want you to see here: first, I pinned and closed the tail post with pinpoints on the bottom, but the top edge still spread open. So I sliced a bit of extra stick at a long angle and used the two pieces as wedges. Cheep&durty, again. Also, notice my two sides are about 1/64″ mismatched; after all I did to keep things lined up perfectly. The frame is square and un-banana’d, though, and after a pass of my sanding block, you and the air will never know the difference. So don’t worry the little stuff!

There’re the basics. After this, you can hang any bit of wood you need for attachment hard points, anything you didn’t put in your original box-side, what have you; and we can go on to fit formers, for a rounded model airframe.

-Collected by Michael J. Heinrich

This article describes the design, construction, and flying of the easiest to build, cheapest little RC glider for schoolyard thermal hunting I’ve ever tried. You can follow along by downloading the free plans.

The Inspiration

While living in North Carolina I had the privilege of flying with the great Carl Dowdy (SFA:bugsoaring). His knowledge of RC & free flight gliders and his penchant for great craftsmanship are difficult to compete against. It can be embarrassing and frustrating to watch how well his airplanes – always simpler than mine – seem to fly.

So far, Carl’s most famous contribution to aeromodelling has been the remarkable 30” RC glider called The Bug. This model landed Carl on the cover of RCM, and has generated what is perhaps the highest form of recognition in the information age – a Yahoo! Group dedicated to the design. Many modified versions have been built.

The Bug is very simple and attractive. It combines cheap, everyday materials (balsa, dowel, and pultrusion carbon tube) in a simple, structurally sound and elegant balance. It looks like it wants to fly and just begs for any number of modifications – conventional tail, setup for discus launching, electric power, etc.

The Bug also happens to be ideal for my needs for an RC glider – small size, easy building and flying, durability. So I built one, right? Of course not. I had to try to design – with my inferior experience and questionable IQ – some thing even simpler, even quicker and cheaper to build.

The Design: the Candy Wrapper

My airplane is built around the wings from the “Skyraider” Styrofoam glider molded by Guillows and marketed to children at craft and toy stores. You can find it online through The Guillow’s website. The stabilizer from the toy is also cut down, hinged, and used as the stab on the Candy Wrapper. The “Skyraider” usually costs about $5.

The other unique element is the Blue Arrow receiver and servo equipment. It is very light and small, functional, and costs about $70 for everything. You can view Blue Arrow’s products at the Blue Arrow Website, and you can purchase Blue Arrow receiver and servo equipment at various online hobby retailers.

All other materials are completely ordinary: light, stiff 1/8” and 1/16” balsa, 1/32” ply, 20.25” of 1/8” pultruded carbon tube, cellophane tape, CA, and – that’s right – a wrapper from a granola bar.

Construction (Free plans available)

Wings first: I cut the plugs off the molded Styrofoam wings in a single stroke that goes at a right angle to the trailing edge. I angled the blade slightly to induce the 1” of dihedral. Putting the two wing halves together was simple…a butt joint with aliphatic resin, then cellophane tape spanwise from tip to tip, top and bottom, 1.5” from the trailing edge, and a 2.5” piece top and bottom 3” from the trailing edge. The left wing features 1/32” ply discs, glued with foam-safe CA, as reinforcement for the discus launching peg.

The wing mount was the most difficult part of the build. I built up a ¼ x 3/8” triangle fillet on each side of the wing half. This is a fragile piece as the grain runs spanwise. I’m not sure, but I sense that it might work better with grain running fore-aft like typical triangle stock. Unlike triangle stock, however, the fillets are not right triangles in cross section. Their angles fit the wing and wing pylon exactly. The wing pylon is light 1/8” balsa with grain running up-down.

The forward fuselage uses light 1/8” balsa with grain running fore-aft. The front piece is an expendable piece of 1/8” balsa. This is like a car bumper. It is smooshed in a crash, reducing damage to the rest of the airplane, and easily replaced. The battery and received are taped to the forward fuselage using double-sided foam tape. The granola bar wrapper, trimmed to the shape shown on plan, is slipped over this and taped to the top of the wing. The fuselage behind the wing is a servo tray built from very stiff 1/8” square balsa. It must be very securely assembled and tightly taped down to the carbon tube. I secured the tape with CA.

I cut the rudder from 1/16 balsa and the stab from the Skyraider’s Depron stab. All edges were sanded round. I would recommend doping or otherwise finishing the rudder. A smooth finish reduces drag. There are many ways to hinge an airplane like this; the simplest that I could think of was to use tape on the stab (glued with foam-safe CA) and tissue (glued with plain CA) on the rudder. I drew the plan with cellophane tape on both surfaces; no reason to mess with the tissue.

The control linkages used the horns provided with the Blue Arrow servos and a pull-pull system with 2-lb test fishing line from Bass Pro Shops (link). The control lines pass through ¼” of 1/16” alu tube near the servos and just before the stab. The control surface horns have the same basic dimensions as the servo horns. I used 1/32 ply.

Flying the Candy Wrapper

The Candy Wrapper prototype flew with virtually no trim adjustments but, because of fairly rearward CG and the Skyraider’s primitive airfoil, it tended to loop on a discus launch. In the end I trimmed it for down elevator, and just hold in some up on the glide.

Some controlled crashes (and one really violent altercation with a manhole cover) proved that the Candy Wrapper design is essentially extremely durable. The wing often popped off on less than perfect landings. I think this is a good thing, and I recommend using very little glue to keep the wing in place.

The tail of the model — a major weak point on small RC gliders — stayed put even on the worst landings. The servo tray(shown on the plan has also held up perfectly.

Unfortunately, the elevator shown on the plan is not big enough! After flying the Wrapper, Carl Dowdy recommends that it should be doubled in size. This is the next thing I will try.

Moving On

I feel that the Candy Wrapper is a design ripe for modification. With more accurately cut wings from blue foam and smooth finishes on all surfaces, performance of this little airplane could go up by 50% if not more. Simply cutting off the bottom 3/32” of the wing – the extra foam doesn’t really do anything – could have a similar effect. It would be very easy and take little time to build a sturdy balsa fuselage pod. The Skyraider parts could also carry electric power.

If you build the Candy Wrapper, or something like it, please drop in the Small Flying Arts Discussion Forum and let us know. We would love to hear from you.

-Andy Mitas, August 22, 2006

Many fuselage plans call for bends in the longerons, particularly around the nose area. If the curve is very slight, we can usually just flex the longeron into shape and pin it until the glue dries. But trying to do this with sharper curves puts stress on the airframe, and the fuselage may distort as the longerons strain to return to their natural shape. This week’s tip presents three ways to pre-shape curves into longerons permanently, to help you achieve tight bends without stressing your structures.

Setting a Curve With Steam

Gently bend the longeron while holding it over the spout of a steaming kettle, and it will hold the shape once removed. Check the curved piece against the plans and steam again as necessary.

Setting a Curve With Hot Water

Soak your longerons in hot water for a few hours and then pin them to the correct shape. When dry, they’ll be warped to the curve you desire.

Setting a Curve by Laminating

Carefully slice part of the longeron in half lengthwise. Start from the nearest end of the longeron and cut to the point where the curve will end (you’ll need a balsa stripper or a steady hand for this). Apply your favorite glue between the laminations, and pin the longeron to the correct shape.

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