On Nov. 27th I started the process of covering the elevator and rudder for my Seamaster. This day consisted of covering the ends and trailing edges of the two control surfaces. This is done first in order to ensure the edges are properly covered and ensure there is no exposed balsa in the end.
In the next session on Dec. 5th I finished covering by cutting two rectangular pieces, one big enough to wrap around the elevator and the other around the rudder. The key here is to make sure it is big enough to cover the widest/longest part (the leading edge in this case) with enough to wrap around the surfaces beyond the trailing edge.
The covering process is similar for both. Starting with wrapping the covering around with the leading edge aligned somewhere in the middle you tack/iron down the covering to the leading edge.
Next you pick a side and iron the covering around the leading edge and to the side of the control surface making sure to work your way from the centre out to the three remaining edges. When ironing at the edges make sure it’s securily ironed at the edge itself and be careful not to have the excess covering touch (cut excess as you see fit). Once done the one side you can trim the excess covering along the edges before proceeding.
Next, flip the elevator or rudder over and repeat on the other side. Starting with rolling the iron over the leading edge and continuing to iron the covering to the other side of the surface starting at the centre of the leading edge out into the middle of the side and working your way out to the three remaining edges. Then trim excess covering. This process left me with covered control surfaces.
On Nov. 20th I focused on covering the bottom of the stabilizer. You can see the stop point for the day with the bottom of the stabilizer covered in the featured image above.
Above you can see the top of the stabilizer (bottom of the covering) I ironed in place. Below you can see the bottom of the stabilizer (one side) covered).
The first step was to measure it all out and cut a piece of fabric over-sized with a straight edge I could put the the inside along the triangle block to have a cleaner finish. I then worked the covering around the leading edge (which was previously sanded to be rounded). You can see me doing this in the picture at the bottom of the post. I made sure to iron from the inside out towards the leading edge and rounding out around the edge to get a smooth finish.
Once that was done I tacked the edges to the bottom of the stabilizer and worked my way around the outside ironing the covering to the balsa of the stab, ensuring I pulled the covering tight as necessary. This left me with the finish below.
Not quite done yet, now that I had the edges of the covering sealed (ironed to balsa) I used the heat gun to shrink the covering. This was done by starting at one of the ends and ensuring I’m always blowing towards the center (away from the covering stuck to the balsa already) and constantly moving and working my way around. You do not want to stay in one place to long or else you will burn a hole through the covering and have to start over. This provided the ‘crisp’ finish you see in the image at the top of the post.
On Nov 17th I finished covering the wing and started covering the tail of the aircraft. You can see in the image below that I covered the seems (joints) along where the triangle stock is in place helping support the stab to the fin. I do the seems first to help keep fuel, etc. from getting in and eating away at the glue, damaging the wood, etc. I also try and do it strategically to limit the places where air can get under the covering and peel it away.
Once the joints were covered I wrap the excess around the leading edge, see aforementioned point about air movement and then trim it from the trailing edge since this has already been covered.
You can see the in feature image of the post that I have started covering the stabilizer. I focused on the convex curves this day (Nov. 18th). This is slow meticulous work as it involves a lot of tiny cuts of the covering along the curves so that you can get it all covered and limit (in an ideal world eliminate, lol) the wrinkling of the covering. I did the outer edges in orange to match the bottom and I did the convex curve on the top of the stab (which will be for the control wire to fasten to and flow over for controlling the elevator) in yellow to match the top. Top and bottom of the stabilizer are going to match the top/bottom of the wing.
Yesterday I continued working on covering the ailerons as well as ensuring a fit between the rudder and elevator.
Prior to fitting the elevator and rudder I needed to V the ruder and elevator so that when hinged to the tail of the fuselage side to side movement of the rudder would be possible as well as up and down movement of the elevator. To ensure the elevator has enough down movement I had to sand the top of the elevator at an angle slopping from leading to trailing edge, seen below.
I finished the night by covering the ailerons. This took a quite a bit of time. I was working on the aircraft for about 2.5 hrs this day.
I measured out enough covering to go around the entire aileron in one piece. In this case it worked out to 5″ wide. I started by ironing a strip down the one side of the aileron and wrapping it around the flat trailing edge, ironing it down as well. Then folding the covering around and pulling tight I ironed it to the one side of the aileron. I subsequently started pulling it around the leading formed edge tacking it down.
I then pulled it tight across the other side and tacked it down near the edges and used a heat gun to shrink the covering to the other side as using the iron in this case would not work and cause plenty of wrinkles and havoc! Once I did what I could with the heat gun I used the iron to shrink up any loose spots and ensure the covering was adhered to the surface of the aileron.
This process was repeated for the other aileron. Since the covering once it cools may slacken in places I haven’t cut the slots for the hinges yet and will have to inspect at the beginning of the next session.
That concluded another building session at Peters. Prior to heading home I visited for a while as its going to be Friday at the earliest that I get to head over again to continue working on the aircraft. Covering is a slow, but therapeutic, process to get it done at least somewhat decently I am hoping :). The therapy part is in it takes my mind off work and other things for that time, lol. Part of why I enjoy building, plus it keeps me in the hobby throughout the off season.
On Oct. 19th I did some more covering, as will be the case for many sessions to come :). This particular day I covered the trailing edge of the stabilizer in caution yellow, seen above, which will be the color of the top of of the stab and wing, as the plan is to match them.
Once the trailing edge was covered and found the hinge slots and cut them out. The next task was to finish covering the aileron tips, seen below. This time I folded the ends down first followed by the wider pieces along the side and folded over the edges. I think overall gave a better look even though it typically folded right around.
On May 4th I worked on the wing and tail of the aircraft.
Seen above I worked on sanding the leading edge, specifically the wing tip corners to get the desired taper.
The fin of the aircraft is composed of two pieces, front and back. I started by sanding off the ‘burnt’ finish from the laser cutting and then glued the two pieces together, pinned them to the board and placed weights on top to hold everything in place while the glue dried. This is seen below, the wax paper is to ensure nothing gets stuck to any glue that oozes out that shouldn’t.
Though my plane according to the plans was complete, Monday I truly completed my aircraft!
Outside of the plans, based on club members experience, I added support wires to the tail. You can see them installed in the featured image above. The reason for this addition is that a known flaw in the design of the aircraft is the weakness of the fin. If you were just flying in circles and figure eights you would be just fine but as soon as you started performing loops and rolls you would have a problem.
That problem is that the forces applied to the fin during these maneuvers would cause the tail to twist making the aircraft unstable in the air. This instability, and perhaps damage, leads to a lack of control and I believe even the potential for the fin to break.
The wires were created by John based on the ones installed on his 4 Star 60. He sautered the ends to bolt to the surfaces onto the wire. The are adjustable for length as you want to make sure they are at about the middle of the top of the fin as well as the middle of the outer edge of the stabiliser into solid wood, but not to close to the edge to ensure a firm hold.
Doing one at a time you line it up and mark where the holes need to go into the stab and the fin. Adjustments needed to be made on the ends to ensure they sit flush with the surface of the aircraft. You then drill out the holes, ensuring you go through in a straight line as you don’t want to be at an angle. Next you put the screws through (screw it in once required) and then put a locking nut on the screw through the stab. Can leave the one through the fin for now.
On Saturday I got to work on my plane again and made some more progress on covering and installation of the fuel tank. One of the discussion Peter & I had in a previous session was what I’d like to do with the cockpit, use covering or paint it. I decided to go with painting it as I felt under the heat of summer with no airflow under the canopy that covering would wrinkle and be a waste, so Peter stained the cockpit green, seen at the top.
I continued where I left off last session by completing the covering of the fin in white. I was able to utilize the knowledge I learned from John in my last session about covering. I was impressed with the result. I didn’t quite get it right the first time so had to switch around the covering and start again (as the glue along the one edge was no longer good after pulling up the heated covering). Throughout the process I had to make some incisions at the top and bottom to allow the covering to come around properly, which includes removing excess when I could.
Tuesday was an excellent covering session and nice to get in back to back days working on my plane. Covering is definitely a time consuming task and the tail with all its intricacies took a lot of concentration and patience. Throughout the process I learned how to do things better, namely so that I do not get the wrinkles when rounding corners causing a jagged/rough looking edge with wrinkles in the fabric.
I started with covering the bottom of the stabilizer in orange and the top yellow to match the colour scheme of the wing (picture below and above, respectively). Measuring the surface at its widest point and longest point to cut a piece at those dimensions plus three inches to have play and room to grab. For each piece the process I went through was (see bottom of article for better approach):
Woodpecker the surface
Line the piece up at the fuselage
Tack it down starting at the centre and working my way out
Start up by the fuselage and apply heat from trailing edge to leading edge (width of iron)
Repeat moving down the stabilizer
Ensure all edges are fully ironed down
Cut excess from trailing edge and tip
Fold leading edge (as have excess) around the entire edge, pull tight & iron it down
This is where the wrinkles really come in!
Trim excess from trailing edge
Doesn’t necessarily look pretty as the wrinkles cause the blade to catch preventing a clean line and instead you get a jagged rough line