• Excellent Laser cutting
• Parts fit perfectly, even when dry fitted.
• Very good flying characteristics
• Makes a great
  "Giant Size Trainer"

• Laser cut parts not labeled (but see text)
• No recommended servo sizes
• What is "Right Trust"?
• Suggested gluing method is questionable
• No suggested control throws
• No detail drawings of critical assemblies are provided.
• Every other step tells you to laminate something.  Get it done all at one time.
• Only photos are shown for fuselage servos, engine and fuel system mounting, but there are two pages on installing a removable hatch.
• Almost 2 pounds heavier than advertised

Now that all the laser cut parts are ready to be assembled, the first thing to do as stated in the manual is to start gluing fuselage parts together. The floor and sides have doublers that have to be aligned with the outside pieces while the adhesive dries.  Since I am using yellow carpenters glue, there is a risk of those doublers shifting away from their original locations, so I followed the instructions which state to hold these parts together with staples.  Yes, good old heavy duty staples from my staple gun were used to keep the laminations together. 

Fuselage sides, formers, the firewall and other parts were glued, laminated and stapled to dry overnight.  The instructions go into considerable detail about building left and right fuselage sides, which is very important.  I'm sure if the builder tried hard enough, the fuselage could be built incorrectly.   I did later find out that still more parts needed to be laminated, which took time.  If all the parts could be laminated at one time, the building process would be quicker.

The manual now jumps to the tail surfaces for some unknown reason and tells the builder to cut several of the 3/8" balsa sheets into smaller pieces and to edge glue them together.  Not wanting to do anything out of order, I followed the instructions, cut the parts, glued them together and let them dry.

Before the firewall was glued into place, I decided to at least mark and drill the holes for the engine mount since there would be limited room to do so later on.  The Zenoah G-26 required 3/4" standoffs to place the prop hub at the correct location, and I used short pieces of heavy duty PVC water pipe for these spacers.  I'll use large fender washers between the plastic and the wooden firewall on final assembly.

Yellow glue was used to assemble the formers into the right side of the fuselage, making sure everything was square to the side, except for the firewall which had 2 degrees of right thrust added due to the angle cut on one of the formers.  All of the formers could only be assembled one way to the fuselage sides, making the job almost error free.

With the formers allowed to cure overnight,the second side was dry fitted to make sure everything would snap into position perfectly.  After a slight bit of trimming of the dried glue in several slots, the second side fit perfectly.

It was then removed, glued into place, and held in position with anything I could find in the shop including old starter batteries, an electric engine starter and some hand weights. Only the front four formers were glued into place at this time.  You can also see the inset made by the fuselage doubler into which the laser cut plastic window material will be mounted later on, a very nice touch.

With the second side dry, the bottom was added,which required a lot of adjustment and making sure all the tabs were seated in their respective slots.  The fuselage bottom aligns the sides perfectly and the resulting fuselage comes out straight and warp-free. Several additional parts were added, including the stab saddle, wing dowel and bolt doublers and the tail wheel mount. 

Balsa sheeting was then cut,fitted and glued into place to cover the top of the rear fuselage, which is the first piece of balsa used in the kit assembly process so far.  It will be trimmed and sanded later on.

Remember those edge glued balsa sheet parts we put together way back when?   Well, the manual now says to cut them out to shape using the printed templates in the kit box.  Frankly, these are the only printed "plans" in the kit, since everything else is laser cut and is supposed to fit perfectly.  They let the builder cut the parts out to see just how good their building skills are.  I used my table top band saw to rough cut the parts, with emphasis on the word "rough", and then sanded them to shape.  The pieces were then glued together and everything was again allowed to dry.

The engine compartment on the Trainer 26 has a set of laminated (where have I heard that word before?) inner plywood doublers that have to be glued in place after they are, you guessed it, laminated. They provide support to the sides of the engine box, but I also plan to add a pair of triangle stock reinforcements between them and the firewall, and probably on the inside of the fuselage also.

We now get to wing construction, where we add a few balsa sticks to laser cut trailing edges, glue together some spar parts and laminate some other laser cut parts that go into the wings. Take extra care to cut the spar parts from the correct lengths of balsa, because if done incorrectly, you won't have enough correctly sized pieces left.  A side view of several sections of the wing structure would be of benefit here. Root and tip ribs were laminated and stapled together and allowed to dry overnight.  I wish I had known that these had to be laminated at the beginning of kit construction which would cut down on glue drying time.

Just about every part of the wing is laser cut, and dry assembly is entirely possible.  In fact the manual tells you to put everything together at first to ensure that all the tabs fit into their respective slots, and they did just that.  Care must be taken to ensure that the ribs are perpendicular to the spars, at least at one end, since there are no plans over which the pieces are assembled.  They also have to be 90 degrees to the building board, except for the root rib, which is set at a 2 degree angle by a wooden gauge. I checked the alignment with a small framing square, finding the entire rib and spar assembly was perfectly in alignment.  Once the balsa secondary spars were added, the entire wing half could be picked up and moved around without the first drop of glue being applied.  Even the ailerons were made from laser cut parts that keyed into one another like a jig saw puzzle. Here is the entire wing panel being held in one hand, without the benefit of any adhesive at all.  That's how well the parts fit.

This is where I began to disagree with the statements in the manual which said "Remember not to glue anything before indicated", followed by  "You can now bond the wing pieces together".  These two statements were separated by the assembly of all the ribs, spars and other wing parts. My disagreement lies in the fact that yellow glue cannot penetrate into tightly fitting wood joints, so all the parts have to be taken apart and glued before reassembly.  Possibly if the adhesive of choice was a CA product, it could be applied to fitted joints, but not yellow glue.  I took everything apart and began to reassemble all the wing parts. this time using yellow glue, and double checking alignment as I progressed.

The laminated root rib is added first, followed by 3 more ribs that sit on the doubled spar. Next, the outer ribs are glued into place, and the laser cut "preliminary leading edge" is then added.This is a sub-leading edge to line up all the ribs and to provide a backing for the balsa leading edge, added later.  A rear spar that sits above the level of the ribs is added next, followed by several other smaller spars.The aileron hinge plate, another laser cut part, is added to the trailing edges of the ribs and provide the mounting location for the hinges in the wing.

Shear web plates are added at the main spar and form a place into which the wing joiner can slide.  They have the dihedral angle cut into one side, so care must be taken to install them the right way.  A secondary shear web is glued to both the front and back of the primary webs for extra strength.  Since I was using yellow glue, I double checked alignment, clamped everything into place and allowed the pieces to dry over night.

Front half ribs are then added, and one of them is laminated, wouldn't you know.  But, I read ahead and laminated them before leaving the shop on the previous night.They both key into the sub-leading edge, but I rechecked alignment, especially the fore to aft alignment of the entire root rib assembly.  A small piece of 1/8" balsa will keep the nose ribs at the correct angle while the glue dries.  The manual says to repeat the process with the other wing panel, but I chose to continue assembling this panel in it's entirety to see how everything else fits.

The wing is turned upside down and the bottom balsa spars are glued into place.  Guess what?  There are more parts to laminate.  Imagine that.  This time it is the servo mounting plates, but I again read ahead and glued them together earlier. The servo mounting plates are glued into the underside of the wing, and the tips of the spars are cut off and sanded flush with the wing tip rib, but that presents a problem.  There is no mention of installing the tip ribs, so be sure to install them prior to cutting the spars. Otherwise you will wind up with a "clipped wing trainer 26!"

The wing tip is aligned by a set of laser cut 45 degree braces and glued into place.  The front of the wing tip will be glued to the balsa leading edge once that is installed.  Oh, Boy, more laminating.  This time it is the wing dowel supports and they are glued behind the sub-leading edge.

On to the ailerons, which are made from laser cut leading edges, bottom and small ribs. All the parts fit together like a jig saw puzzle as mentioned before, and even the hinge angle is set up correctly.  Here we go again, laminating a set of aileron horn support plates, and gluing them into the correct position, using the wing panel as a reference.  There is a right and left aileron on this plane, and they have to be assembled correctly.  A balsa trailing edge is glued into place, the whole assembly sanded to shape and they are ready to hinge to the wing panel.

The point style hinges need some sort of block through which holes are drilled and the hinges glued into place.These blocks are made from laminated (I just knew it...) 1/8" balsa strips that are cut to length, glued into place and sanded to shape.  There are 6 aileron hinges on each side and corresponding blocks added to the rear spars in the wings.  After the glue dried, holes are drilled and made a bit larger for the hinge to fit correctly.  After all hinges are installed and checked for alignment and operation, they are removed and won't be reinstalled until after covering.

A cardboard tube is supplied for servo leads to pass through the wings to the center section and after they are cut to size, they are glued into place.

The wing is now set flat on the building board to keep everything straight and the inner section of the  panel is sheeted with 1/8" balsa back to the rear spar.  I pinned the panel down to the table to keep everything straight.  A set of plywood rings are laminated and glued to the inside of the root rib to support the anti-rotation dowel to be added later. 

The balsa leading edge is now glued into place and shaped to match the fuselage outline.  Since I had not built the second panel, I only rough shaped the leading edge with my Master Airscrew razor plane, waiting until later to do the final shaping when both panels are joined. 

The bottom center sheeting is now added and a plywood backup plate is glued to the inside of this sheeting.  A hardwood dowel is then drilled for the wing bolt, cut and sanded to shape and glued into place with the dowel protruding from the top sheeting, added at this time.  With the center section sheeted, a trailing edge stick is glued into place.

Now I get the opportunity to build the second wing panel, making doubly sure I built the "other side".  Answering your question, "Yes, I have", but not this time. 

The completed wing panels are now joined using the plywood joiner, making sure the alignment dowel mates into the hole on the opposite wing panel.  There may be a little sanding needed to get the joiner to fit perfectly, but go easy as this is the only part that keeps the wing panels at the correct angle.

The joined panels are now placed on top of the fuselage and the dowel holes are drilled.  This may get a little tricky since there are no holes in the wing leading edges, and there are holes in the dowel reinforcement pieces inside the wings, but you cannot see them.  If the wing is centered on the fuselage front, the holes will like up perfectly.

Before the wing bolt holes are drilled, the wing must be aligned to the tail of the fuselage.  This procedure is called "tramming" and is done by making sure the distance between the center of the tail post is equal to the distance to the same relative point on each wing tip.I use a metal tape measure, but string can also be used.

Once these distances are equal, the wing is secured to the fuselage using tape and the bolt holes are drilled, using a drill bit that is a few sizes smaller than the size of the bolt.  Since the kit uses 1/4-20 nylon bolts, I used a 3/16" drill to make the holes and then opened the wing dowel holes with a 17/64" drill for a little flexibility.

The bolt holes in the fuselage are then tapped 1/4-20 and a little thin ZAP is applied to the threads to harden them.  After the ZAP cures, the holes are tapped again and the wing is bolted into place.

The fuselage needs some type of front cover and the kit includes parts for a windshield and a hatch that can be removed. Well, wouldn't you know it, more lamination.  This time some 1/8" balsa sheeting is glued together to make the windshield and hatch and these parts are then fitted to the fuselage.The windshield is glued into place permanently and the hatch is made removable with some wood screws.

The main landing gear  is now mounted to the fuselage, but I found the instructions to be a little vague. The aluminum gear leg is mounted at a place that locates the wheel axles to be more than 3" ahead of the wing leading edge.  This could make smooth landings difficult since once the tail drops, the fuselage can pivot on the forward mounted wheels and the wing may start flying again.  I mounted the gear at the indicated position, but I may be moving it rearward once I make a few landings.

The wheels are mounted using 8-32 bolts and safety nuts.  I then noticed that the distance between the wheels is extremely small, measuring only 16". I feel that  this distance should be approximately 25% of the wingspan, making it closer to 21", but I can't do anything about it other than replace the gear legs.  As you can see in the photos, the wheels just look too close together. I then took it upon myself to remove the gear from the plane and take the wheels and axles off the aluminum gear.  Using a bench vise and a couple of pieces of hardwood, the "modified" gear now sits about 1" lower to the ground but has a space between the wheels of more than 19", which will add to the stability of the plane on the ground. 

Now we jump back to the tail surfaces where we join the elevator halves with a piece of dowel and add the hinges.  If the builder choses to use dual elevator servos, this joiner will not be needed.  CA type hinges are supplied in the kit, but point style hinges, similar to the ones used on the ailerons will work just fine.  Make sure to drill the holes using some sort of gauge to keep the hinges inside the wood. 

The rudder is hinged the same way, but the hinges will not be glued into place until the model has been covered.

Here are two photos of point style hinges that are installed into a balsa sheet.  One of them is a good installation, and the other is a bad installation.  Can you tell which is which?

The pivot point of the hinge must be even with the surface of the drilled part.  This can be done by first drilling the part for the main size of the hinge, in this case it's 1/8". Then a larger drill bit is used to open up the outer 1/4" or so of the hinge hole so that the larger section of the hinge has a place in which to slide easily.

The stab is now set on the rear of the fuselage and aligned to the wing panels, both horizontally and vertically.  The fin is set over the stab and minor sanding may be needed to obtain a perfect fit. The rudder is attached with a few hinges and the slot for the elevator joiner dowel is cut out and trimmed.  The tail parts are then removed and will not be reinstalled until after covering.  The manual tells to use two pieces of triangle stock between the stab and the fin, as these provide the needed strength to keep the parts in place.

I won't bore you with the details of filling and sanding, mainly because it is a basic model building technique and it's hart to photograph it with a cloud of sanding dust hovering around the work area.  Let's just say that I applied filler material, allowed it to harden for at least 24 hours and then took the parts outside the shop where I proceeded to sand away anything that didn't look like an airplane. Once all the sanding dust is blown or wiped away, the model was covered as stated above.  This took me about 6 hours, including the installation of the striping tape.

You will also see that the Trainer 26 has been magically covered, using Top Flite Monokote and some Hangar 9 UltraCote trim pieces.  I also used some 1/8" trim striping tape from the auto parts store to outline all the trim colors.

The stab was epoxied to the fuselage and allowed to cure over night.  The fin was then epoxied to the stab and the top of the fuselage and also allowed to cure.  In both cases, alignment to the wing, both horizontally and vertically, was checked before the epoxy had cured completely.

Hinging of all the control surfaces is done using Pacer Hinge Glue and the supplied point style hinges.The ailerons are hinged to allow the pivot points to be as close to the surface as possible while still allowing full range of motion.

The elevators and rudder are hinged in the same manner, making sure there is only a minimum hinge gap.

Now that the Trainer 26 is covered, the installation of all the linkages, servos, engine and radio equipment can begin. The elevator servo, a single Hitec HS-645MG, is mounted into one of the fuselage holes after cutting the covering open using the tip of a hot soldering iron. 

Here is a photo of the slot in the rudder that needed to be cut to clear the elevator joiner rod.  

The rudder servo, another HS-645MG, was installed on the opposite side of the fuselage and connected to the rudder using 4-40 rods and clevises.You can also see the double-sided ruder horn I found in my parts drawers. 

The tail wheel assembly supplied with the Trainer 26 kit would have been perfect except that the rudder was just a bit too long and would hit the steering arm.  I raided the parts bins and found this tail wheel bracket and wheel that I pressed into action.  You can also see the coil springs that come with the kit to connect the rudder horn to the steering arm.

The Zenoah G-26 engine was now bolted into place using the stand-offs and lock washers on the mounting bolts.  You can see the holes that needed to be cut into both sides of the front of the fuselage to clear the muffler and carburetor. I also mounted the engine "right side up" rather than with the cylinder pointing down.

I used a plastic tube type throttle linkage to connect the throttle servo, a Hitec HS-425BB unit, to  the carburetor.

At the carburetor end, I used a nose wheel steering arm and an EZ connector for engine speed adjustment.

Final details include a simulated front window (yes it's really tinted a lot)  made from black UltraCote. The laser cut plastic side windows are glued into place using Pacer Canopy Glue.

I also installed the receiver, a Spektrum 7000 series DSM2 unit and made up an aileron Y harness from old connectors.

After allowing all the adhesives to cure, I took the Trainer 26 out into the light of day and put the wing on the fuselage. The model actually balanced between the 25% and 30% point of the wing chord, meaning that once the spinner and radio batteries are installed, the balance would be at the very worst, "adjustable".

The manual lists no control throws for ailerons, rudder or elevator, leaving these dimensions to the judgment of the builder.  I set up my ailerons with a  1.5" up and 1" down throw, the elevators +/- 1.5" and the rudder was set for 2" each way.  Dual rates were set for about 65% of these dimensions and I added 25% exponential on each channel.  The first flights will be flown on low rates and will determine if my guesses at control throws were close.

I also put the Trainer 26 on my digital fish scale and found that it weighed 14 pounds 15 ounces, meaning that the completed weight would be a bit higher than the figure stated in the manual.  But even with that, the wing loading is quite low for a plane of this size at about 25 ounces per square foot.

This is where the instruction manual stops, giving the builder only a series of photos to look at and determine how the rest of the model is to be assembled.  This model is listed as a "trainer' and while it probably should not be used as a first kit project, the title of trainer should include all the information needed to complete the assembly process.  AMR lists a disclaimer at this point that basically says to complete the model in a "safe and reasonable fashion".  They also say that the photos show the radio and engine installation "based on our initial prototype...have worked out perfectly for us".  All I can add to that is to use your best judgment as to sizes of control linkages, fuel systems, radio installation, engine and ignition installation and if you are not completely sure of anything, enlist the help of a local modeler to help you complete the project safely.

Everything seems to be in order, the plane is balanced between 25% and 30% of the wing chord, the batteries are charged and the weather for the upcoming weekend looks to be just about perfect.

Let's go flying!