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.
Tuesday was the day everything came together and I my aircraft was fully assembled. Previously in the week Peter & John balanced my plane to determine how much weight was required. The aircraft was quite tail heavy. Need to remember that as you move away from the center of gravity (CG) the effect of 1lb of weight is compounded. This means that even though the engine, wing, battery, etc. is all up at the front of the plane the tail still wanted to ‘sink’.
In order to counteract this John & Peter determined how much weight was required to place up in the nose so that the aircraft is actually a little nose heavy. They determined the weight required and already had the one side of the piece of metal sanded and a piece cut out for the drain hose from the engine to go through allowing the fuel to exit instead of pooling on the bottom. I then drilled two holes into the piece of metal.
After yesterdays session you can really get a sense of what my aircraft will look like (without the wing anyways). I started my day with covering the hatch cover. I wanted to break up all the white on the fuselage and since Peter and I had the same idea for what color should be used I went with green. Before covering I had to make sure that there was clearing for the throttle linkage which involved sanding down the one side. Once that was done I covered the surface and folded over the edges like I have done previously. This also means that for the front it involved doing a bunch of small cuts to get the covering folded over the curved edge decently.
John came over to check things out and while he was there we bound my transmitter to the receiver. I haven’t installed that yet as John’s going to bring over some velcro for that task; however I know where it is going to go and already hot glued some tubing to the side of the fuselage to run the longer wire at a 90 degree angle to the other for reception. I set up a new model in my transmitter (named it 4Star60) and the various leads were hooked into the correct places on the receiver. We were not able to get the desired effect for the throttle after doing endpoint adjustments on the throttle control arm and in the transmitter itself so will have to look at that again. We were able to adjust the servos (mechanical adjustments) and the linkage near the control horn to get us satisfied with the movement of the rudder and elevator for this first crack at it. John had to go and then Peter and I hooked up the wing to test the ailerons. I had to reverse RAL so that when pushing the joystick left the plane would bank left (as was reversed originally).
Tuesday was on the shorter side (1.5hrs) but accomplished the two goals that were set out for the evening, cutting the canopy and securing the pilot in place.
The first task was to cut the canopy. This may sound like a simple task, but the thing to remember is that I only have one and if I screw up we have to order a new one. That said I took my time. It initially was curved such that it was flat with the ground all the way across and had an edge/lip all the way around. This would make it easier from a manufactures perspective as they just put it on the mold and walla! Every plane is a little different in how the top deck curves, etc. so this allows you to cut it to your aircraft. Peter mentioned some come with the canopy cut to size, but guessing there is more precision in the top deck and where it needs to sit?
I had John’s canopy to use as a guide to get me started, but even then if I’d of cut it exactly like his it wouldn’t have fit my aircraft. First I lined up the front ‘band’ you can sorta see in the pic with John’s and marked where the back of his canopy was with a pen that I could clean off. I then cut out the enclosed part of the back and worked my way towards the pen mark taking out chunks, or as John likes to say hack-choo. There was a process finding the right tool to cut the molded plastic as Peter had no suggestions and I don’t know what others use (please comment and let us know!). What I ended up finding worked best for me were metal cutters with the straight blades, not the funkily curved ones (sorry I’m no Tim the Tool Man Taylor 🙂 ).
Last Tuesday I got to work on my plane again and been so busy since I’m only now getting around to blogging about it.
The first thing we did was install the wire for the tail wheel. This involved first bending the tip of the wire into a 90 degree angle and ‘sanding’ the wire to rough it up a bit which allows the glue to stick better to hold the wire into place. Then needed to drill a hole into the button of the rudder for where the end of the wire (the part bent up at an angle) will slide into. This provides a sturdier fit into the rudder, since this wire steers the tail through the wheel/rudder connection.
The remaining part of the wire that goes along the bottom of the rudder needs to be recessed into the rudder itself so that it is flush. In order to accomplish this I first lined up the wire and traced two guide lines along the bottom. Using the guide lines I drilled tiny wholes along its length to carve out a groove. I then alternated between using a drill bit to run along its length a tiny file to sand out the inside. I alternated and repeated until upon one of my checks the wire sat down into the rudder to my satisfaction. Note that we used the plans to figure out how far back the wire needed to go and also need to ensure that not to much sticks out at the leading edge that would interfere with rudder movement.
Once that was done and glued into place we then cut a piece out of a fiberglass sheet such that it would wrap around about 2 inches on each side. I then brushed glue over the fiber glass, ensuring to role any air pockets out of the fiberglass over the wire and down the sides. Once this was done it was left to dry.
The fiberglass provides additional support / reinforcement to the tail wheel assembly.
Next I went back to working on the wing and installed the invasion stripes on the bottom of each wing panel, seen in the feature picture at the top. Placing covering over top of covering can lead to an excessive amount of air bubbles forming as air gets trapped between the two layers. In order to help mitigate this issue I used the Top Flite Woodpecker Perforating Tool:
Saturday I got over to Peter’s for another building session. We started by going over what Peter had done. In order to not ‘waste’ my time on some of the easy but tedious stuff Peter will do some of it for me when he has a chance so that those things don’t hold us up in the project. He then goes over how he did it so that I still gain some exposure to the task.
One of those things was attaching the hatch covers to the bottom of the wing, seen at the top and bottom of this post, and the other was running the leads from the servos out the two wholes in the top of the wing. He used the previously run string to pull the wires through, since covering is now applied. By tying the string around one end of the wire (ensuring you go along the connector and between two of the wires so the string doesn’t slip off while being pulled). You then slowly pull the string through, working the string and lead back and forth if it catches, until you are up and through the hole. Repeat for the other servo.
You can then connect the leads to a receiver to test the servos with your transmitter.
Hinges are used to connect control surfaces (i.e. ailerons, rudder, elevator) to a main part of the aircraft (i.e wing, fin, stabilizer). How I learned to do this is as follows and I will be using the context of installing the ailerons.
First I use a motorized hinge slotting tool (i.e. Great Planes Slot Machine, Fig. 1) to make the hinge slots into the trailing edge of the plane and ailerons. This was done, and matched up, prior to covering. Then once covered you can use the back of a scalpel to gently poke around about where the hinge slots should be. Once you’ve poked through and found the slot you cut along its length exposing the slot.
Tuesday I was able to get in some more covering and visiting. I started by covering the ailerons, which as you can see from the pic above I did in green. Kevin stopped by for a visit to see how things were going and a bit of a chat. It is nice to see guys interested in what’s going on and my progress, even if it is a bit nerve racking at times but we all need to start somewhere, lol.
I also covered the servo hatch covers, seen below. Which was done the same colour as the bottom of the wing so that they match and blends into the rest of the wing.
In order to more easily cover the hatch covers I detached the servos. The overall covering was pretty straight forward though a little awkward due to the small surface area. John taught me the proper way to cut the covering away from the opening where the servo arm goes through. Because you want to have covering over the edges of the opening to protect the wood you cut down the centre of the opening (length wise) and then two cuts into the ‘corners’ of the rounded ends. From there you fold the covering pieces over and iron it down to the edge and back side of the cover.
An ‘oopsie’ was discovered in this process where one of the blocks wasn’t glued to the hatch cover and thus fell off. Good thing this was discovered now, by John, so it could be glued and clamped so that it is properly attached.
Saturday was another great building session. John stopped by for a visit to check out how things were coming along and contrary to the ‘hack’ job he voices I believe he thinks I’m doing a pretty decent job :).
Thanks to Peter for trimming off the excess of the top left covering I didn’t have a chance to finish last time as well as along the leading edge and sealing that down. Both Peter & I learned something new yesterday from John, which is how to cut a pretty straight/clean edge. After covering the top of the left panel, sealed all around the edges and using the blow drier to shrink of the center need to fold some over the leading edge to prevent wind from getting under and peeling it off.
Once adhered the time came for the trim trick demonstrated by John. Depending on where you want the line you allow the side of the blade to rest against the ‘natural’ curve at the desired angle and follow it along the length of the wing while you are making your cut. Ideally you want to do the entire cut from the same position as changing position can alter the cut reducing the visual straightness (for lack of a better word) of the line. This also ensure that it is cut to the same length throughout. Once cut you then use the iron to roll over the top of the leading edge onto what remains after the cut to adhere to to the wing.
The last part was cutting a piece for the center of the wing. Had to mark the wholes for the dowels, which I then cut out, and once fitting the covering over with the dowels through marked the two square wholes where the cables will come out. I then applied the covering to the sheeting on the wing keeping the iron level (sides to the bottom/top) and working from the center out to the left, followed by center out to the right and vise versa. Always want to start in the center so you work any air bubbles, wrinkles or other imperfections out to the edge in hopes they disappear :). Once done I found the two square holes, generally marked via the string previously pulled through the marking wholes. I made sure the covering was adhered firmly around the edge prior to cutting out the covering to expose the holes. We still have the string coming out, don’t want to loose it, as the string will act as our guide when running the wires for the servo in each wing panel.
I did my best to line up the bottom edge of the L panel yellow covering to look similar to the R as well as the center to be lined up with the L & R wing panel.
To wind up the evening you can see I started covering the ailerons, just the tips so far, which will be done fully in green. Before starting that next time I am going to go over the wing to make sure it’s done as best I can get it.
The aircraft is really starting to come together and will be starting to cover the tail soon and working on the fuselage. As a fun aside I need to find my pilot, which can be about 2-2.5″ tall with a fairly wide base as will want to glue and screw into place.
Tuesday I was able to work on my plane for a couple hours.
Prior to covering the top of the wing I needed to cut the covering that was over the servo hatches. After cutting the covering into an ‘X’, corner to corner, I turned the wing back around and ensured that the covering is firmly adhered around the opening. I then folded the cut pieces over, one per side, and performing little cuts where necessary to get the desired fold. Then using a tiny iron I adhered the covering to the side of the wood before flipping over and adhering the leftovers to the inside wood (provides better attachment then cutting the excess short) and then only trimming where little bits stuck up higher than the ‘height’ of the wing so as not to affect when covering the top.
This can be seen in the image below:
Once that was done I covered the top of one half of the wing (seen in the featured image at the top). I ran out of time as I was getting tired and hungry so I will have to perform the finishing touches next time prior to starting the other wing panel. The touch ups include making sure there are no sagging parts, trimming the excess along the edges, etc.
As a note, this time prior to even starting to cover the top I used the woodpecker over the entire exposed sheeting where the two wing panels are connected.
Saturday was the first building session of the new year after Christmas holidays. John stopped by and showed me more about covering. He also brought his woodpecker over which is a device used for making tiny wholes in the surface when you are covering. In my case I used it when covering the wood sheeting where the wings connect. You can also use it when putting covering over top of covering.
The idea behind the woodpecker is that the tiny wholes it makes allows for air to escape instead of getting trapped between the covering you are applying and the surface you are covering which would create air bubbles and creases that can be a royal pain to get out.
This session I covered the entire bottom of the wing using safety orange. Peter and John weren’t kidding when they stated that covering takes a long time in order to do it right and get a decent look. One definitely needs to strike a balance between perfect and good enough or else you’ll never get done! Lol.
With covering the bottom (and eventually I will do similar for the top) of the wing I did it in 3 pieces. The left wing, right wing and centre piece. Once measured and cut I started by pinning into place and ironing down parts of the edges to adhere some of the covering initially. I then worked on ironing the rest of the perimeter starting in the middle and working my way to the outside alternating between the top edge and the bottom edge. The bottom or trailing edge piece overlaps the green I did for the trailing edge and you need to make sure not to overheat it or else you risk the underlying covering (green) coming off.
Once I got the edges done (as well as what overlaps onto the centre sheeting) you use a ‘special’ blow dryer to heat up the covering. You need to ensure you keep the blow dryer at a safe distance from the covering (approx. 3″ I believe) and constantly moving or else you risk burning a whole through the covering. Then you need to start all over again.
Felt good to be back working on the plane and I’m looking forward to tonight’s session as well.