The Sig 1/4 Scale Cub build series is well under way! In part two of this build series, we will focus on the rudder assembly. Last time in part one we built the main fuselage formers and also the rear formers F8 through F11. If you have not seen part one, click here to view part one of the Sig Quarter Scale Cub build series.
As with any build that I start, I like to begin with the simple aspects of the build. For example, the rudder is usually a piece that can be framed up fairly quickly which helps to give a sense of accomplishment right a way. This goes a long way in helping the builder stay motivated during the entire construction process!
For the rudder I also tile printed that portion of the plan and taped the pieces together and covered them in wax paper. In this case it’s a matter of finding the correct printed parts mentioned on the plans and utilizing some of the straight balsa stock included with the kit. For a few of the straight pieces in the rudder, you will have to cut and shape these by hand using the balsa stock provided. Most of the curved parts of the rudder are included on a printed sheet of 3/8” balsa. Be sure to make note of proper thickness and width of the balsa stock the plans call for.
The best way to cut out the printed parts is to use a small bench-top band saw and cut them to within 1/16th inch of the printed black line. Then shape the pieces accurately to the line using a disc sander. Some shaping by hand will need to be done on some of the inside curves. Again, take your time here – a lot of test fitting over the plans to make sure everything is within the lines!
Once all the parts are cut out, lay them over the plans to test the fit. Once you are satisfied with the fit of the parts, I like to tack them together using thin CA. Use a magnetic building board or pins to hold the parts securely as they are glued in place. Once the main parts are in place, work on the inner framing. To ensure that the angles are accurate, you can use a bent T-pin to score the under side of the stock to mark the angle it needs to be cut at on both ends. Next, cut it close to the line using a razor saw and then finish for a nice snug fit with a disc sander or sanding block. A disc sander will help to ensure the angle is square along it’s entire face.
Score underside of stock with a pin
Once all the framing is completed, I like to use my favorite wood glue and brush a small amount into any gaps that need filling. Some final sanding will be needed to finish the part for final assembly.
Part 1 Main Fuselage formers and Rear Formers F8-F11
The Sig J-3 Cub Build is now under way!
One of the first parts that are easy to build are the main fuselage formers and the rear balsa formers F8-F11. You will have to build the main fuselage formers from the balsa sticks provided – cutting them to size according to the plans from the 36” stock provided. Rear balsa formers F8-F11 are die cut balsa pieces you will have to glue together at the seams.
Before starting the build, I like to sort the balsa and included ply wood die cut parts into piles. With the Sig RC48 J-3 Cub kit, much of the balsa is supplied as die cut, printed balsa sheets, or in the form of balsa sticks. It helps to organize things; when the manual calls for the needed parts, they will be easier to find. Most plywood parts are already die cut and are easily removed from their sheets.
Before starting this build I decided to have all four plates of the plans scanned into PDF. This allows me to print out certain parts without having to cut up the original plans. I print them out using the tile feature in Adobe’s Acrobat PDF viewer software. I also print them with a ½ inch overlap. This allows me to line up the tiled sheets much more easily. I tape them together using small pieces of Scotch tape. Using a large window as your background allows you to see through the pages allowing you to line things up perfectly as you tape them together!
I like to build off my magnetic building board – that I use for all my model building – to ensure the parts are aligned as accurately as possible. Take extra time to make sure the main fuselage formers are square, will result in an air frame that is precisely built and accurate. Remember straight air frames fly better and helps to reduce any trimming issues!
Build the main fuselage formers as shown directly over the plans. Use a good wood glue or even epoxy here. Using slight pressure on the joints (using the magnets you can “wedge” the parts together as they dry) will result in a very strong and sturdy joint! Add some weight on the pieces that glue on top of the former sides to ensure a good bond.
Glue the rear former halves F8-F11 together using wood glue and tape on one side to ensure the seams are pressed tightly together while they dry. Place some wood glue in the seam, and then press the joint together by hand and wipe out any access glue that seeps out. Finally, place the formers in between to pieces of wax paper as they dry. Add some weight on top to ensure they dry straight and flat. Use a piece of scrap board and a ten pound dumb-bell as weight on top of the formers. The scrap wood board will help distribute the weight evenly over the formers.
Tape on back side of peices
brush in glue or epoxy into open seam and fold shut
Finished pieces! Very tight seams!
Once the glue has dried the formers are now complete! They may require some final sanding once mated to the fuselage sides.
The Senior Telemaster RC airplane makes a great trainer and is available many sizes: from mini all the way to a giant 12 foot wing span! With it’s slow flight characteristics and docile handling it’s truly a joy to fly – even for more experienced pilots!
Another primary advantage of the Telemaster design is its ability to be able to carry a lot of weight due to the low wing loading. This make it a great platform for modifications – as there is room to add some weight without effecting flight performance!
This particular Telemaster I acquired was not in very good shape and was in need of some repairs. I restored it earlier this summer: fixed the broken balsa stringers, recovered the wings, and shaped new ailerons for the wing. The fuselage was also twisted and needed to be straightened. I was able to do this by the holding the correction (twisting it past the correct point since it will naturally spring back a little) in place while shrinking the covering with an iron. I added a set of flaps!
One other item I wanted to do was add some lighting to the wings and the fuse. Originally I had just added some LED strip lights to the main wing during my first round of repairs, but after my initial testing I decided I wanted to light the entire plane!
When I was recovering the wings with Ultracote, I drilled wholes in the ring ribs so I could run the LED strips through the wing. I ran a set in the front of the spare and also at the rear of the spar so I could light the entire wing. One thing I wanted to keep in mind when positioning the LED strips in the wing was to try to position the LED’s in such a way that the wing was “indirectly” lit – taking advantage of the internal reflection of the white Ultracote. This makes the lighting appear evenly distributed throughout the entire wing giving it a more natural “glow” effect.
The main colors I used for the wing and the horizontal stabilizer, were red and green – with the green LED’s on the right and red on the left. I used neutral white for the fuselage interior. I placed the fuselage LED strips on the bottom so they could shine up – again taking advantage of indirect lighting. Using this technique where possible really makes it glow and the light looks very even!
Removed the old covering for access to the bottom
positioned in ribs
LED strip, shining outward
drilled small holes for wires
drilled small hole in fuse to run wires inside of the fuse
Measuring the amount of covering I will need
When it came time to install the LED strips into the horizontal stabilizer, I developed a new technique for placing the lights; perhaps one I wished I would have thought of instead of drilling holes in the ring ribs! Sometimes you “learn as you go”! For the horizontal stabilizer, I cut small slits in the rib and slid the LED strip in place as close as I could to the spar location. Once I was satisfied with the positioning, I added some thin CA to the small gap to restore the integrity of the ribs in the stab (the Telemaster uses an air foiled design for the horizontal stabilizer). Again, I ran a strip in front of the main spar and also at the rear – both strips shining outward from the center. This made for very even light distribution!
Marking center of fuse line
Use a straight edge to make a nice clean cut in the covering
gently begin to peal it back to expose the fuselage.
Use tape to hold covering out of the way
Installing the light in the fuselage, I decided the easiest method was to cut the covering down the very center using a straight edge so I could access the entire bottom of the fuselage. Of course hindsight would dictate to install the lights before I covered it the first time! For the LED strips in the fuselage, I stuck two strips of lights back to back (in this case I did want one set to show down and one set to shine upward into the inside of the fuselage). I ran two double strips on each side of the center line of the fuselage. I wired the back-to-back pieces together using jumpers I had made from some scrap servo lead wire.
sticky side up
position one strip sticky side up
LED’s stuck back to back
test fitting inside of the fuselage
cover exposed ends.
Once I was satisfied with the placements of the lights, I secured the LED strips and wire leads with a hot glue gun. Hot glue works very well for this sort of thing!
I wanted to be able to control the LED lights from my transmitter. I decided to use the Turnigy Receiver Controlled Switch to do that. This switch simply gets wired into the positive lead of your battery, and the other end connects to an open channel in your receiver. Since this plane is a glow powered plane, I’m using two separate batteries, a normal NiMH 5 cell – 6.0 volt pack for the receiver and servos, and a 3S lithium polymer battery for the LED strips. One thing to note, is that for this circuit to work properly, the ground (black wires) of both batteries need to be connected together! Without doing this the switch will not operate! I’ve included a wiring diagram of the configuration for this type of setup. Mode II is the diagram you should follow when using two separate batteries.
If there ever were an RC plane that one were required to own – the RC Polaris Seaplane designed by Steve Shumate would be it! Made from 1/4 inch depron foam sheets, it’s a quick build for most and very low cost!
One of my local club members had a partially completed Polaris he had been working on and never got around to finishing it. It was given to me by this club member so I wanted to finish it and get it flying. This is actually my second Polaris I’ve owned as the first one met and early demise when flying to close to the ground!
I was able to reuse all my electronics from the original Polaris park flier I had, so everything was mostly a direct fit. Part of the fuselage and tail section had already been started and some of the control surfaces had already been hinged with tape. On my original Polaris, I used Ultracote iron on covering for the hinges and it worked very well! I decided to do that on this one as well and replace the tape that was partially coming off. Surprisingly Ultracote covering sticks very well to depron foam; even using the low heat setting of around 220 degrees Fahrenheit. I did some tests on small pieces of foam to see how much “stick” it had… it seemed to hold better than any of the packing tapes I had tried in the past!
digital Servos
Castle Thunderbird ESC
2200KV motor
Futaba 6Ch Receiver
Castle 10 AMP BEC
Ultracote Hinges
Ultracote Hinges
On my original Polaris, I felt the tail section was a weak point so I added some 1/16 balsa there to make it slightly more rigid.
Clamp and let dry
1/16th Balsa
I also reused the original wood control horns for the ailerons and just carved some small slots in the foam and secured those with a foaming polyurethane glue. These glues work great if you have to fill some larger gaps. For a more secure bond, use clamps.
The rear vertical stabilizer was missing so I opted to make one out of 1/4 inch thick balsa and then carved the center out to reduce the weight. I also laminated this with some thin CA to stiffen it up a little more. I printed the template from the original Polaris plans and simply cut it out with my no. 11 blade xacto knife. I used 30 minute epoxy to secure it into the rear tail section and pinned it in place once I was satisfied everything was square and straight.
With the original Polaris RC Plane I had, I had made a motor box that “gripped” the tail section a little better as I had an unfortunate mis-hap with the original where the motor mount had torn away from the foam!
Next, it was time to begin running some wiring for the 2200Kv motor and Castle Thunderbird 54 Amp ESC I was using. I also decided to not mount the servos inside the body compartment this time. It is not as waterproof I will admit, but it made running the control rods a lot easier! As a result of this modification I felt it balanced slightly better than my original Polaris, since it allowed me to move the battery to a more forward position. Having to replace a servo is now much easier too.
Once I had all the servos mounted, ESC, and receiver in place, it was time to add the top cover. I secured this using polyurethane glue. I pinned it in place along some of the curved sections and also weighted it down with a pillow and a couple of 10 lbs. weights. Using a pillow helps to disperse the pressure more evenly.
The bottom rear section was also missing. I cut some balsa to fit and then sanded this to final shape. I secured it with polyurethane glue and weighted it down for a few hours.
Once all the major work was completed, it was time to do some sanding to help smooth out any bumps and rough corners. I rounded over most of the corners and edges. I also hit the edges of the wing and rear control surfaces just to take off any hard edges.
Finally, I cut my battery hatch. I found the approximate location by just setting the battery on the top of the fuselage and determined where the proper CG should be. I cut an opening that was slightly larger than the battery for easy “in and out”. I placed scrap foam pieces in the nose as a “stop” so I know exactly where to place the battery each and every time. I also made a small latch by cutting in a scrap piece of balsa and securing it to the foam with epoxy. I drilled a hole for the screw and strengthened the balsa piece by coating it in thin CA. A simple Ultracote hinge works well on the ear section of the hatch as it acts like a trap door.
I added some more covering to the wing leading edges to help increase visibility. I’m not certain I’m done covering it yet… I’ll fly it and see where I should add pieces to help aid with visibility!
This was certainly a great project to work on! It’s amazing how well these little foam planes can fly. I highly recommend any modeler build one!
I was in the market for a sport/3D plane after flying a 40 size Kaos and exhausting the flight envelope of my trainers. When I first saw a review for the AJ Laser 230z in Model Aviation it really caught my eye. I watched a number of videos on YouTube and I really liked the way it flew!
This really is a plane you can fly in full 3D mode or as a gentle sport flyer. I do prefer the more “pattern” style of flying than 3D but this plane can really do both!
I placed my order for the 73″ inch version and received it 2 days later! Fast shipping to say the least! It came extremely well packaged and nothing was damaged at all. The covering was virtually wrinkle free. All hardware that was needed for either glow/gas or electric setup was included.
The manual is fully illustrated and should be a fairly straight forward assembly for anybody who has assembled an ARF before. I took my time during the build process; all in all I had about 15 hours into it to get it flight ready. I did not use their recommend electric motor, so this undoubtedly added to the assembly time as I had to fashion an additional spacer out of 1/4 inch ply wood to accommodate the Firepower 1.60 I wanted to use.
The hinge slots came pre-cut and everything was a very precise fit.
For initial setup I used their recommended expo settings but reduced my control throws by nearly half as I wanted a very docile maiden flight. Setting things up at home as precisely as you can goes a long way in ensuring a successful maiden flight. This includes making sure ailerons are a level as they can be with the wing at mid stick and even deflection on either side. I measured the control throws in degrees using a pitch gauge I use for helicopter setups. Also take measurements and re-measurements to ensure that your horizontal stabilizer is square to the wing as much as possible.
I did the maiden flight in early April of 2015. 10 seconds into the flight I had a huge smile on my face! The plane just flies so smoothly it’s almost unbelievable! Just a few clicks of right aileron was all it needed to achieve perfectly straight flight!
This plane is one of the easiest planes I have in my fleet to land. It literally just floats down and tip stalls are essentially a non issue! Customer service is also top notch with AJ Aircraft!
This is truly a home run from AJ Aircraft! I highly recommend it!
Here is a great review video of (one of many on YouTube)
