Preparing to Build
Tips and Techniques
This page is used to compile all the little tips and techniques that I have been picking up along the way. Although there are separate areas to divide the subjects, the items in each area are listed as I thought of them. There is no relevance to the numbers and the relative importance of the tip.
- One thing that you see right away in the builders manual is that most of the drilled holes require reaming for a proper fit. A reamer isn't exactly a local hardware store item. Most of the sizes that you need can be obtained rather inexpensively from Grizzly Industrial Tools. Some of the slightly undersize reamers used for tight fits will require purchase at a specialty location.
- Reamers are usually sold as 'chucking reamers'. Most of the reaming that I have done did not require a drill motor. The reamer was easily turned (and controlled) by hand. So, how do you hold the thing? I purchased a 3/8" drill chuck - just the chuck - and mount the reamers in it. The chuck provided a good hand hold to grip and turn the reamer.
- Bearings and bushings need to be press fitted into tight areas. You need a method to provide straight and even pressure over the surface of the fitting. I have had success using an arbor press, a small table vise, and woodworking screw clamps. I pick the tool that will fit the work location.
- Solid rivets are easily installed with a hand rivet squeezer. Consistant results were attained.
- A gravity feed HVLP (High Volume Low Pressure) paint spray gun was purchased for about $50 and uses my regular compressor fo an air source. It has worked extremely well applying the fabric covering finishes.
- I used a soup ladle to move/measure the polybrush and polyspray liquids into a coffee can for reducing and mixing.
- I purchased a MD Smart Level to set the flight controls. This thing is great! I also used it for general levelling of the aircraft, instrument panel alignment, and propeller pitch setting.
- Sometimes, you need to drill a hole through a bolt. This can be frustrating and break many drill bits. It is a lot easier using a Saf-T-Block drill bushing.
- Electric wires are terminated with ring terminals, butt splices, or spade clips. All these things are crimped on to the wire. Get a ratchet style crimper specifically designed to give the double crimp needed by these rascals. It saves time and gives consistant results.
- Get a bandsaw to cut the aluminum parts. I use a 1/4" blade with 14 teeth per inch. It makes a smooth cut without distortion.
- Almost every metal piece will require filing to remove saw marks or bring to a final fit. Aluminum is such a soft metal that it will soon load up the file teeth. Clean the file with a file card to remove the metal and keep cutting.
- There is a requirement to drill a 1/16 inch hole through the center of a /4 inch steel pin. I broke several drill bits before I hit on a proper way to accomplish the task. I drilled a 15/64 hole through a block of oak and inserted the steel pin into the block. This held the pin tight and allowed it to be clamped to the drill press. I then drilled the 1/16 inch hole perpendicular to the pin through the wood and steel simultaneously. The wood held the tiny bit steady and guided it accurately. The result was a clean hole.
- An area at the root of each rear wing spar had to be cut away to provide a relief opening which allows the spar to pivot when the wing is folded. It is not easy to cut a piece out of a round aluminum tube. I performed the task using a Dremel tool with a spiral carbide cutting bit. The same tool was used to cut slots in the fiberglass seat pan to allow the seat belts to pass through.
- Holes in the instrument panel were cut using a Unibit (for smaller holes) and a fly cutter (for the larger ones). Make sure the panel is clamped in place before trying to cut one of the larger holes at the drill press.
- How do you cut those rectangular holes in the instrument panel for radios, Hobbs meter, and the ELT head? I carefully marked the area to be cut, then used a cutout wheel on the Dremel tool. I went though several wheels - they will break if you pinch them in the metal. I did the cuts freehand, and they came out surprisingly well.
- Many of the powder coated areas will have to be sanded to remove some of the build-up before the parts will fit. I first encountered this on the elevator hinges.
- The flap handle mount point was close enough to other structural members that the bolt head had difficulty clearing. This part will be almost impossible to disassemble once the center console is in place.
- In order to place the clips which hold the bottom of the firewall to a fuselage belly tube, I had to remove the floorboards and rudder pedal assembly. It would have been easier if I just fabricated and installed these clips prior to working on the floorboards.
- I had the avionics shop prepare the wiring harness for my radio installation. It has been a huge time saver.
- Nylon cable ties are quick, but the sharp edges left behind after you trim them can be a pain. Also, nylon ties are adversely affected by exposure to the sun's ultraviolet light. I used the cable ties temporarily during the initial wiring runs, then I bundled the wires using waxed rib cord. I then clipped off all the cable ties. This resulted in a bloodless installation. By the way - the waxed cord is an FAA approved method of bundling wire.
- I sure wish that I had done the initial installation and back drilling for the cargo area floor before I did the fabric covering! Make your life easier by mounting some nutplates on the underside of the floorboard tabs. It is extremely difficult to contort oneself when trying to secure the floorboard with screws and nuts. The cargo sack gets removed for the condition inspection, so the nutplates will pay for themselves in no time.
- I put all of the hardware into an organizer cabinet. Label the drawers with the Skystar part number and the AN designation.
- Get some extra cotter pins. Invariably, you will find a perfectly valid reason to remove hardware secured by a cotter pin.
- I made a jig for drilling nutplate rivet holes by screwing the machine screw in from the back side of a spare nutplate. Set the machine screw into the hole drilled into the part which will anchor the nutplate. Match drill the first rivet hole, Cleco it, then match drill the second hole.
- The plastic sight guage tube in the right fuel tank sprung a leak after just two months of exposure to gasoline. It turned very brittle. I am searching for a replacement material that will better stand up to the fuel.
- Covering the wings was a big job, but not overly difficult. It helped to heat form the fabric over the trailing edge before attempting to glue. Also, don't go crazy with the amount of glue applied under the leading egde. It has a tendency to pool and form lumps.
- Skystar provides just enough fabric to cover everything - if you are careful where you trim and you don't leave too much extra around the edges when you make the rough cuts. Fit the fabric to get the best use prior to trimming off the roll.
- I purchased some extra supplies to complete the fabric covering. A roll of bias ply 2 inch tape really helped in the curved areas. A roll of 6 inch tape made it easy to cover the leading edges of the wings, leading edge of the rudder, and trailing edge of the vertical stabilizer without multiple pieces. Polyspray was purchased for UV protection.
- Heat forming the fabric around the tubes prior to gluing made for a much better result with fewer creases.
- When making the final cut on a piece of fabric that will be a seam, I would first paint a small stripe of polybrush over the area and allow it to dry. This acted as a fray-check and kept the threads from unravelling after the cut was made.
- I chose to paint my aircraft with PolyTone. It makes fabric repairs very easy - especially when compared to an Aerothane coating. I was happy that I had the PolyTone when I poked a hole in the underside of my horizontal stabilizer and had to patch it.
- Denatured alcohol is the Skystar solvent of choice for cleaning and prepping parts. It also does a great job removing the adhesive left behind when you remove the labels that Skystar placed on each part. It is fairly inexpensive to buy in a one gallon can, but it hard to handle in the original container. I cleaned out an empty liquid dish detergent squeeze bottle and filled it with denatured alcohol. Now it can be easily dispensed.
- The structural adhesive (two part epoxy) is usually mixed in small quantities. I purchased a bag of 100 plastic spoons to get the adhesive out of the quart cans. I then mix the two parts together in disposable plastic bathroom cups. The epoxy mixture is then placed into a small Ziploc bag, one corner of the bag is snipped off, and the epoxy is squeezed where it is needed.
- Don't use plastic containers to mix epoxy varnish. It can dissolve some of the plastic and contaminate the mixture. Use a glass jar or a ceramic mug
- Make a couple of sturdy trestles (saw horses) about waist high with a top beam of 4'. They will be needed to work on the wings.
- My shop has a couple of columns which support the loft floor. In order to make it easier to move the fuselage, I constructed a dolly which has full swivel castors. The main gear sits in this dolly. I can now easily move the aircraft in any direction.
- I used a Dremel tool with a fiber reinforced cutoff wheel to trim the fiberglass. It works great!
- I used my bandsaw to cut the polycarbonate for the side windows. Final edge dressing was done with a belt sander.