How To
Build A Wood Kit Trainer
Part One
By: Frank Granelli
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LT-40 Kadet ARF photos from Sport Aviator Article
Most Basic Trainer kits today are sold as either Ready-To-Fly (RTF) or Almost-Ready-To-Fly (ARF). Almost all such aircraft reviewed in Sport Aviator are in one of these classes. For more details on assembling these aircraft, review the Sport. Aviator articles, How To Build Your ARF Trainer (Parts 1-3) and How To Assemble Your First RTF Trainer. This next series of articles will be about building a Basic Trainer from a wood kit. We’ll be using the SIG LT-40 Kadet wood kit as the project airplane. The LT-40 Kadet ARF is reviewed in the Sport Aviator’s On The Flight Line Section.
Photo 1
The SIG LT_40 is the modern version of the SIG Kadet which debuted in the early 1960’s. The Kadet has been the premier Basic Trainer ever since. My first Kadet flight was a real eye opener for me. I learned to fly RC on a Jenson Ugly Stik. The Ugly Stik was a great airplane and the first (I believe) model aircraft designed for proportional RC systems. Fifty years later its descendants live on in all the “Stick” airplanes available today. But the old Stik did have a Symmetrical airfoil wing and was quick to respond to the pilot’s control inputs. Today, it would be classed as an Advanced Trainer/sport airplane.
Nearly three years into my RC flying career, I was a club instructor and taught a student pilot to fly using his SIG Kadet. Wow, was the Kadet ever easy to fly, stay ahead of and then land. It was the best trainer I had ever flown up to that time and remains one of the best in the world. It is available as both an ARF and a wood kit.
So, that is why we choose the Kadet. But why in the world build one from a wood kit when the ARF is available and flies just as well? That is a good question, especially considering the higher quality of today’s ARF aircraft. The answer comes in several parts:
Before I am accused of being old fashioned and silly about building a wood kit in this thrilling age of ARF and RTF models, I need to be honest. I am NOT recommending that your first Basic Trainer be built from a wood kit. My thought is that only returning modelers might do that and then only a very few of those will build.
No, your first Basic Trainer should be either an RTF or an ARF. This gets the pilot into the air faster so piloting skills can be more quickly mastered. Your second airplane should definitely be an ARF as well. This provides a back up airplane should the worst happen.
But somewhere in your early RC career, you should build from a wood kit. You may want to fly an older RC airplane that is only available as a wood kit. You may want to build an advanced scale airplane such as those from Balsa USA or Top Flite. In the real world, your first wood kit will most likely not be a Basic Trainer.
But, the skills gained from building a Basic Trainer such as the LT-40 Kadet are directly transferable to the more advanced wood kit airplane you will most likely be building. They are identical. This being Sport Aviator, a “beginner’s magazine”, we are using the LT-40 Basic Trainer as an example. And who knows, maybe you will be sufficiently inspired to build the LT-40 as your “backup” trainer.
The Balsa USA Stik 40 Plus review touched on some techniques and tools used in building a wood kit airplane. But that article was mainly a kit review. Sport Aviator has already reviewed the SIG LT-40 Kadet so this article series will focus more on the building than the flying. But there will be some flying information since this LT-40 will have some modifications designed to improve its flying abilities and its appearance.
This is an article series. How many parts will be in the series is somewhat unclear. The articles are being written as the aircraft is being built. I don’t even yet know what colors the final design will be. So, here is Part 1 of the series.
Part 1 details building the LT-40’s main wing. How an airplane flies has much to do with its main wing. Both of the major modifications being made to this LT-40 are contained in the main wing. In addition, building this wood kit allows us to position the wing ribs for maximum performance and the spar webbing for maximum durability.
 Photo 2 |  Photo 3 |
The task is to turn all those pieces in photo 2 into the wing in photo 3. This is not hard, can be a lot of fun and allows the builder maximum flexibility. Photo 1 pictures many of the tools and adhesives used in building a wood kit. Among the most needed are:
ª A high-speed rotary tool such as a Dremel® tool with sanding and cutting bits.
ª Both thin and medium CAA (fresh) and CAA Accelerator.
ª If you wish, a bottle of Aliphatic Resin glue and an application “syringe”.
ª A deep razor saw (~2 inches)
ª Both 5- and 12 minute epoxy with several epoxy brushes, cups, maybe micro balloons and mixing sticks.
ª A small hobby miter box
ª Pin clamps and hobby clamps (from any hobby store)
ª A few hobby razor knives with sharp #11blades, #16 blades and 1/2 in. chisel blades
ª A flat place to build.
Photo 4
A truly flat surface is a necessity. I use an old solid wood door that had been damaged in the lumber yard as my table top. A corner had been clipped but the door itself is perfectly straight and warp-free. To build, I usually put a 1 x 4 ft. redwood shelf on the door. Redwood almost never warps and is soft enough to pin into but then self-heals when the pins are removed.
This time, I used the Great Planes magnetic building board. While pins can’t be used into the steel base, the board arrives with numerous magnetic clamps. The vise clamps on the left are the most useful so extras were purchased. The small black clamps hold 3/16 in. or 1/4 in. spars in place while gluing. The redwood building board will be used for building the fuselage.
 Photo 5 |  Photo 6 |
We are going to transform that neatly packed box of stuff into the airplane shown in photo 6.
Photo 7
To make this transformation, we are going to use the plan sheets included in the kit. These plans are used during almost all the construction. The plans not only illustrate what parts to use where, but they supply each part’s positioning. Look closely in photo 2 and note the excellent instruction manual. This is the best manual we have yet seen for a wood kit. It is extremely detailed and very accurate.
While there may be technique differences in this build project from the manual, the manual is correct. Following it will produce a fine LT-40 Kadet. But the plans themselves have a minor problem. Even though a venerable wood kit company such as SIG should know better, the plans as supplied are folded, not rolled. Folding the plans results in the creases shown in photo 7 and creases change the part spacings.
The first building step is to tightly roll the plans. Make the roll as tight as possible. Twist the inside edge of the roll for even greater tightness. Be careful of paper cuts as the plan material is tough and sharp. Leave the rolled plans for about an hour to remove the creases.
Photo 8
Identify all the wood parts used in to wing and compare them to those listed in the manual. Read through the manual at least once and then re-read the wing sections. Make sure there are no questions in your mind. If some arise, comparing the manual to the actual parts involved usually answers the question.
Photo 9
Cut out the plan for the right wing panel according to the instruction manual. Yes, we did construct the right wing first here despite the instruction booklet’s order to build the left panel first. The right panel better fit our building area for photo purposes. Whichever side you choose, building allow lots of flexibility, spread the now creaseless plans out on your building board. Make sure the plan is flat and fully stretched. Tape or fix in place.
Note the box of parchment paper in photo 9. The manual says to use wax paper over the plans to protect them and to prevent gluing the plans to the wood. This is fine. But wax paper can leave a residue on the wood. Parchment paper protects just as well but releases cleanly without leaving a residue. Parchment paper is available in just about any supermarket wherever wax paper is sold. Cover the plan with the protective paper of your choice. Again, make sure the protecting layer is fully stretched and taped in place.
 Photo 10 |  Photo 11 |
First, lay out all the wing spars. Check for warps. The spars in this kit were exceptionally straight but even so, a few slight curves did appear. The idea is to match contrasting curves or to eliminate any slight warps during the laminating process. If the warp is truly bad, more than a quarter inch, replace the piece with one from the hobby shop.
What is contrasting warps? The two rear balsa spars were slightly bowed. When assembling the ribs, make sure the spar bows face each other, top and bottom. This cancels out the slight warp yielding a straight wing.
When laminating parts, especially spars, my choice is to use aliphatic wood adhesive. Medium CAA does work well but may not allow enough time to position the parts in the few seconds before it sets. If you are straightening a part using the lamination process, using CAA makes the task nearly impossible.
The first step is to laminate a 12 inch long balsa strip to the 1/4 x 3/8 inch hardwood spar. If the spar has a slight curve, as this one did, position the curved side towards the inside. Affix the spar to the plan lined against a metal straight edge. Using either pins or clamps, hold the spar firmly in place, apply the adhesive and spread it out on the shorter piece. Always apply the adhesive to the smallest piece when possible.
Photo 12
Make sure the spar remains straight and clamp the top laminating part in place over it. Make all four front spars in this manner. Once the adhesive dries, about an hour, you’ll note that the spars are now reinforced and straight. Affix (pin or clamp) them in place on the plans as shown. Do the same for the rear balsa spars.
Photo 13
Carefully remove the wing ribs from their die cut sheets. These ribs removed cleanly. If you feel too much resistance when popping out the ribs, lightly sand the rear of the sheet. The ribs will about pop out by themselves. Note the different rib shapes and their locations. The part numbers are stamped on the ribs.
Place a few wing ribs in position, no adhesive, to insure that the spar spacing is correct (photo 13). The ribs should fit firmly into position without compressing the spar notches. If they do not, recheck the spar positioning.
Photo 14
Before gluing in the center ribs, position the center wing sheeting in place between the front and rear spars. Always put the printed side facing into the wing or the numbers might show through the covering. Once positioned correctly, weight or affix the sheeting in place and run a thin bead of medium CAA along the front and rear on the sheeting where it meets the spars. Do the same for the rear sheeting between the rear spar and the trailing edge. Do not install the front sheeting at this time.
Photo 15
Leaving a few ribs in place, no adhesive remember, affix the trailing edge in place on the plans. The trailing edge on this airplane has rib notches. Use these for the rib spacing, not the plans. Plans sometimes change dimensions due to humidity or temperature changes and can be off by 1-2%. SIG says to use the trailing edge notches, not the plan positioning. Most other wood kits have trailing edges without rib notches. In those instances, use the plan spacing.
Likewise, this airplane has a flat bottom airfoil so the ribs fit firmly against the building board during construction. The airplane you will most likely be kit building will have a symmetrical airfoil. In these instances, the plan will show a leveling “spar” that is affixed somewhere to the building board towards the trailing edge. The rear of each rib rests on this “spar” during construction. This aligns the ribs producing the desired wing shape. Fortunately, that particular complication is not required for this airplane.
Photo 16
Here is one area where you can improve upon an ARF. You can bet the farm that ARF manufacturers do not perform this operation. Remove all of the W5 (the most common) wing ribs. Then weigh them using the gram scale. This scale is available from most diet stores, vitamin shops and from BP Hobbies. Write the weight on each rib as shown.
The rib weights varied from 3 to 7 grams due to density differences. Separate the ribs by weight: Use the heaviest ribs for the left wing. The lightest ribs are for the right wing. Two medium weight ribs, ~ 4-5 grams each, are saved for the wing tips. Wing tips take a beating and a slightly more dense rib in this position is a good idea.
Use the 4-5 gram ribs at the tips because you do not want to put the heaviest ribs out that far on the wing. The heavier the wing tips, the less precise are rolling maneuvers and the greater the rotational momentum during rolls. Greater momentum requires more control inputs to stop the rotations.
Photo 17
Working inboard from the wingtip, place the W5 ribs in place starting with the lightest in that side’s batch and working towards the center. The lighter ribs go to the outside to keep the wingtips light for better rolls.
Why use the lightest ribs in the right wing and the heaviest in the left wing? Because, the muffler will be on the right side in this airplane. Using the heavy ribs in the left wing will help to laterally balance the airplane without using extra weights.
Photo 18
Insure that each rib is vertical and aligned with the plans as much as possible. Tack glue each rib in place with thin CAA. Also install the center W-2 to W-4 ribs in place. Make sure each rib is vertical. The instructions say to insert the spar webbing now. I usually save the spar webbing until all spars, the front and trailing edges are glued in place. If not done correctly, spar webbing can warp a wing. If the wing is already almost completely built, warping is then more difficult.
If you want to install the webbing now, go ahead. Make sure the webbing is tight but does not put a strain on the rib positioning. Spar webbing is vertically grained balsa that fits inside the top and bottom spars and against both ribs. The webbing creates a D-tube wing and converts the top and bottom spars into a solid, rigid “I” beam.
Once the ribs are tack glued vertically in place, install the top spars. Check all the alignments and then use medium CAA to glue everything down. If you are installing the webbing later, apply the medium CAA only to the front and rear spar notches; not to the center section.
Photo 18a
If you are using aliphatic resin wood glue, holding the top spars in place using pin clamps (available at hobby shops) is a good idea. These pin clamps have a thousand uses in building. They were also used to hold the leading edge in place before applying the medium CAA.
Photo 19
Check the leading edge shape. There is a difference between the top and bottom. Check the plans and note the wing side view presented on the fuselage plan set. Identify the top of the leading edge and mark it.
Then pin the leading edge in place on each rib. Check that all is straight and then glue the leading edge in place using medium CAA.
 Photo 20 |  Photo 21 |
Once all the adhesives are set, install the spar webbing. Make sure the webbing is vertical and has a snug, but not tight, fit. Sand a little if necessary. I used a 3/8 inch square block about 2 inches long as a “square” to insure that each web was vertical. Spar webbing is not required for the two outboard sections of the front spar or for the three outboard sections of the rear spar. The wing areas closer to the fuselage usually sustain the highest air loads.
Photo 21 |  Photo 22 |
As another strength modification, you may install some spar webbing in the two most interior rib bays. The plans do not show this as necessary. But the airplane as designed uses rubber bands to hold the wing onto the fuselage, Rubber band mounting reinforces the wing’s center section.
But this airplane will be modified to use bolt on wings because I detest greasy rubber bands and their hit or miss wing positioning system. As designed, the wing center is probably strong enough, especially when fiberglass is used (we will be doing that on this aircraft as well). But spar webbing is cheap and light, so why not use it in the center?
To make the webbing for the first two rib bays, cut some scrap balsa from the unused sections of the wing sheeting die cut balsa. Make sure the webbing is cross grain as shown. Use a # 16 razor blade (photo 21) to cut out the new web by cutting around one of the interior spar webs before installing it (photo 22).
I am not sure if this is this blade design’s intended purpose but the # 16 blade is ideal for cutting out duplicate parts. The non-blade section easily rides around the template part without damaging it while the sharp razor blade area cuts out the duplicate part.
 Photo 23 |  Photo 23a |
Insert the spar web you made in between W-2 and W-3. Install the webbing between W-1 and W-2 only after W-1 is installed. SIG provides a dihedral gauge for installing W-1. Position W-1 in place at the inner edge of the root sheeting. Use the rear spar notch for positioning. Then place the gauge (actually a wooden square with one edge not at 90 degrees, against W-1 so that the rib top tilts slightly towards the wingtip. The gauge determines how much tilt. Then glue in place using medium CAA. Insert the final spar web.
Photo 24
Note that the main spar notch is larger than the spar on both W-2 and W-1. This makes room for the center dihedral braces.
 Photo 25 |  Photo 26 |
Once everything is dry and with the wing still firmly on the building board, locate one of the plywood dihedral braces (photo 25). Note that the ends have a middle cutout. Slide one end of the brace into its slot until the end of the cutout contacts W-1. Hold the brace firmly against the spars. Then use a razor saw to gently cut away the part of W-1 that is blocking the brace. Make several cuts instead of one big one that could split the rib. Do the same to the rear spar slot.
W-2 does not need to be cut as the brace’s open center allows its two ends to reach all the way through W-2 and onto W-3.
 Photo 27 |  Photo 28 |
Place both dihedral braces against the drawings in the instruction manual (photo 27). Make a center line as shown in the photo. Trial fit each dihedral brace into its center slot (photo 28) but do not glue in place at this time. Although SIG instructs you to glue the brace now, making sure that the brace’s bottom is firmly against the lower sheeting, making a positioning error here is all too likely and extremely damaging. After the other wing half is built, we will join the two halves as if they were an ARF wing. This method allows perfect alignment and dihedral.
Normally, this would be the moment to remove the wing half you just made from the building board. But there is one more major modification we are going to make. Flat bottom wings usually have a lot of adverse yaw. Newer pilots usually have some trouble controlling their trainer at slow airspeeds when right aileron application swings the nose way off to the left.
To eliminate this problem requires trimming the ailerons so that the upward moving aileron has more deflection than the downward moving one. Doing that requires, you guessed it, installing one servo for each aileron. Installing two aileron servos also provides for flaperon operation. The stock SIG LT-40 uses only the older, single aileron setup for control.
 Photo 29 |  Photo 30 |
Take a piece of 1/16 in by 3-inch wide, stiff balsa. As photo 29 shows, the rib spacing is just less than 3 inches. Cut the balsa sheet to fit between the ribs. Measure the internal distance from the front spar to rear spar and cut the balsa sheet to that length.
 Photo 31 |  Photo 32 |
Trial fit the balsa sheet into the rib bay that is the 3rd out from the end of the center sheeting. Why here? This is a compromise location. Placing the control horn out more towards the aileron’s center helps reduce any aileron flexing and reduces any chance of possible fluttering (one of the problems inherent in center servo aileron torque rod linkages). But remember, we are trying to reduce wing tip weight in order to enhance roll control performance. Therefore, the servo is mounted two rib bays inboard of the aileron’s true center. This is a compromise but a lot better than the torque rod linkage would have been. The torque rod linkage’s many limitations are why we didn’t locate both aileron servos in the wing’s center.
Trial fit the balsa piece so that it lays flat against the building board and is tight against all four sides without putting pressure on any one side. Sand until the fit is good. Then remove the balsa piece, center your servo on it and cut the servo hole so the servo just fits through the hole (photo 32).
Photo 33
Place the balsa sheet just trimmed on top of another balsa sheet and cut out the matching part for the other wing half. This insures that both servos are equidistant from their respective control horns. Identical linkages are always the easiest to tune.
 Photo 34 |  Photo 35 |
Cut two pieces of 1/4 in. by 1/2 in. spruce longerons to match the balsa sheet’s width. Use the hobby miter box to insure that the ends are square and will butt against the ribs without gaps, if possible. Insert the balsa sheet between the ribs, mark where the spruce servo mounts will go and glue in place with medium CAA. Do not apply adhesive to the areas that will be occupied by the servo mount rails.
 Photo 36 |  Photo 37 |
Tests fit the servo mounting rails and then use a small triangle to insure that the rails fit squarely into the rib bay (photo 36). Line up the rails with the front and rear edges of the servo cutouts and glue in place. Later on, the balsa sheeting covering the rails where the servo mounts will be removed to allow the servo to slightly “indent” into the wing.
Once the mounting rails are glued in place, use some short lengths of hardwood triangle stock (1/2 in. square spruce cut length-wise into triangle stock if none is available at your hobby shop) to reinforce the mounting rails against the ribs as shown in photo 37.
If this had been a larger aerobatic airplane such as a scale fighter or Extra, we would have reinforced the balsa ribs with 1/16 in. thick plywood before mounting the servo rails and triangle braces. But this installation is more than strong enough for a Basic Trainer.
Photo 38
Use a high-speed rotary tool or a sharp razor knife to cut holes in the inner ribs so the aileron servo extension wire can reach out to the servo. Be sure to include holes in W-2 as well. Lay some strong thread or other small string in the holes and tape in place. This thread will be used later to pull the servo wires through to the wing center when mounting the servo in the finished wing.
 Photo 39 |  Photo 40 |
Remove a wing tip from its die cut board. The wing tips are made from light-plywood. This type of plywood differs from the usual aircraft plywood in that it is made by laminating a thin sheet of balsa wood between two thin layers of plywood. It is much stronger than plain balsa wood but lighter than normal aircraft plywood. Since the wing tips usually take a beating during handling, light plywood is a good material for use here.
Use a small sanding block to sand the edge flat as shown. Cut away the bottom spars flush against the outer-most rib. Then Slide the wing tip into the top spars that are longer than the wing half as shown. Once firmly in place, glue with medium CAA. Glue the tip to the outer rib and all spars. Glue the spars from the inside.
Photo 41
Using the tip itself as a guide, cut off the extended spars outside of the wingtip. Final sand the spars to match the curved wing tip. Always use a sanding block for any sanding job, large or small. This prevents uneven sanding.
Before removing the wing half from the building board, slide the lower, front wing sheeting into place under the wing ribs. Glue the sheeting only to the front spar. Do not glue to the leading edge or the ribs except at the very rear of each rib. those areas will be glued in place after removing the wing from the building board.
Remove all the clamps and remove the wing half from the building board. It should be straight, warp free and very strong. The top front and middle center sheeting should be missing and the lower front sheeting glued only at the rear. Turn the wing half over and lay it against the board. Gently press the front of the lower front sheeting against the leading edge.
Photo 42
It should fit onto the ribs and just inside the leading edge. If it is too long, use a straight edge to cut it to the correct length. If it is too short, cut a thin piece of scrap balsa and glue in place with wood glue only after the sheeting is glued into place.
Apply some slow dry adhesive such as wood glue to the ribs. Then bend the sheeting, step-by-step slowly into place against the ribs; pinning in place with pin clamps as you go. When you get to the leading edge, hold the sheeting in place and apply medium CAA. Use CAA Accelerator here if required. Let the slow adhesive dry.
OK, that wing half is now ready for joining. I’ll wait right here while you go ahead and build the second wing half. Let me know when you are done and we will play ARF as the wing halves become one. SIG Supplies a dihedral jig that makes the joining a pleasure.
Photo 43
Prepare both root sections for joining. If any spars extend past the bottom of the root rib, remove the overhang using a razor saw. Then lightly block sand the entire rib section with a 12-inch sanding block making sure that the wing tip is raised half the 3.75-inch dihedral or 1 7/8 inches.
 Photo 44 |  Photo 45 |
Trial fit the two wing halves together on your building board just as if they were two ARF wing halves. Note in photo 44 that I had to remove a small section of the center top sheeting for access. It was not possible to insure that the dihedral brace would fully contact the front spars without the clamps. That is why I made the previous suggestion to leave the top center sheeting off until the wing was joined.
SIG provides a great dihedral jig for joining the wing halves (photo 45). Place the jig under one of the tip roots as shown. Weight the other wing half flat on the board just as you would do with an ARF wing.
 Photo 46 |  Photo 47 |
Once you are satisfied with the fit, it is time to join the wing panels. Use an epoxy brush, a cheap brush available at all hobby shops, to apply 12 or 15 minute epoxy to the areas touched by the dihedral brace, including the balsa sheeting areas, and to one of the root ribs. Butt the raised wing half against the root rib of the half laying flat on the board. Insert the dihedral braces and clamp them in place. Make sure they are tight against the bottom sheeting.
Tape and clamp the root ribs and wing halves together as shown in photo 47. Make sure the joints are tight all along the length of the root (called the wing “chord”). Check everything again including that flat wing panel is indeed flat against the building board.
Allow the epoxy to set. Photo 47 shows the final assembly. If you sanded the root ribs correctly and removed the overhanging spars, one rib will fit firmly against the other providing a tight, strong joint.
If there are any gaps, maybe along the bottom root seam, fill these with a thin mixture of epoxy and micro-balloons (again, from any hobby shop). Tape out the area around the section to be filled to protect the surrounding wood. Mix some 12-minute epoxy in a cup adding micro-balloons until the mixture resembles a thick cream soup.
Apply the mixture to the gap and allow it to sink in. Remove the protecting tape before the epoxy sets. Keep the wing in position, upside down in this example, until the epoxy sets. Do not fill gaps in the root joint with the usual wood fillers. While they do cover the open area, they are not able to add any adhesive strength. The root rib wing joint is one area that must be strong.
If epoxy only was used to fill the gap, the thin adhesive would run too far into the joint and would probably crack as it sets. Adding the micro balloons prevents cracking and over-penetration while also supplying adhesive strength to the joint.
 Photo 48 |  Photo 49 |
The instruction booklet says that the trailing edges‘top and bottom are identical. As the photo clearly shows, this is not the case. However the edges do form the same angle against the wing with either side up. Possibly that is what is meant by identical.
Photo 50
I placed the thicker side facing upwards as shown. Place the trailing edge against one wing side’s trailing edge until the inside bottom is just at the wing center joint. The top should be extending a tiny amount past the joint. Use a sanding block to sand an angle into the trailing edge piece so that both top and bottom are parallel to the center joint. Remove that piece and do the same to the other.
 Photo 51 |  Photo 52 |
After sanding, glue one half of the center trailing edge piece to the wing half making sure it is straight and flush against the wing’s T.E. both top and bottom. Since the wing mounting bolts might be, or might not be, passing through these parts, I used 5- minute epoxy to apply them. Remember to apply adhesive to the center sides of this piece so they are also glued to each other. The rubber bands in photo 51 make sure that this joint remains tight during the adhesive’s set time.
Once everything is dry, install the two remaining top center sheeting pieces. Do not install the front two top sheeting pieces now. We will need access to this area to install the front wing hold down dowels. That step will happen after the fuselage is built as the dowel locations will be determined by the fuselage’s main front cabin former.
This would normally be the time to install the ailerons. But I am one of those builders who prefers to attach all the control surfaces at the same time. Control surface installation is a critical step, no gaps or raised edges wanted here. I find I achieve the best fit once the major surfaces have been rough sanded to their near their final shape.
So, for now the wing is complete. This is the hardest of the building tasks. If you take extra time, getting to this point will require about 3-4 long evenings. Figure on taking as long as 25-30 hours building the main wing. The important point is to make everything is straight and firm. The job might go a little faster if no modifications are made. But then, modifying a wood kit is usually the best part. So far, the modifications have been:
ª Installing twin aileron servos to trim out adverse yaw and add flaperons
ª Making the right wing lighter than the left, improving lateral balance
ª Installing the heavier wing ribs toward the center for better roll control and/or compensating for the wing mounted aileron servos
ª Setting up the wing for bolt-on installation instead of rubber band hold downs
ª Making the wing’s center stronger by adding extra spar webbing
All those improvements were made just in building one part of the airplane. Imagine what we can do on the whole aircraft. We are gradually making this particular aircraft truly our own. Can you feel the sense of accomplishment yet?
Next time we’ll be building the fuselage. I have to go now for I hear the glue, wood and building board calling my name. And, the call is getting stronger with each stick I glue in place.
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