Stabilizer rev 1.2 The SE5a stabilizer is the heartbeat of the tail and is recreated like the full scale version. All tail pieces depend on the stabilizer. It uses the steel fittings, pulleys, inspection windows and flying wires found on the original. Eight flying wires attached to the stabilizer and eight pulleys are used in the stabilizer. All these features add weight to this area. You can counter balance with some weight up front. The fuselage instructions show some steel being added to help with this. The spars have pre-drilled holes to help locate the hinges as well as pulley brackets. The kit supplies the servo tray which goes under the pilot seat that route the cables to the stabilizer pulleys. It would be painful but the stabilizer could be removed from a finished plane if needed. The stabilizer is one piece. You will construct the stabilizer first as the pulley components will be added later. The front of the stabilizer is mounted to two vertical fuselage braces. The original stabilizer incidence was adjustable by turning the wheel next to the pilot s left leg. In the kit the stabilizer is not adjustable. You should use wood glue such as, Titebond, not CA glue during this construction. The inspection windows are done like the original which are held in position by fabric. If you want to gain access to the pulleys, then you can make a removable frame like some of the modern full scale versions have. A quick overview. You will secure the spars, add ribs and rib capping. The spar is completely covered with fabric even the backside of the spar. There are drainage eyelets in each bay that you will add as well on the bottom side only. Note center body of the main rib 5.115 is slightly taller than the spars. The front end of this rib is slightly smaller than the back end. The rib has a arrow laser etch in it indicating the correct orientation. The arrow should point to the elevators or the rear stabilizer spar when the main rib is position in-between the spars. Locate the two stabilizer spars 5.111 and 5.112. The spars might need a slight sanding or clean up from the CNC process. Note - the front spar has a group of four holes in the center spar area. These holes will be used for the servo pull-pull cables. Orient the front spar so the holes closest to the spar edge are furthest from the building table. These holes are there to help you locate the pulleys. They can be enlarged if needed. The rear spar is symmetrical and can go either way. To help align the main ribs to the front spar you will need to raise the front spar some. Position the spars in place on the plans. Raise the front spar above the building table with some scrap 1/16-inch balsa spacers. Secure the two spars onto the building plans. The front spar should have some scrap 1/16-inch balsa spacers below it and the rear spar should not any. Starting from the root rib at the center of the stabilizer add the main ribs inbetween the spars as well as the outer ribs 5.207 and 5.209. Make sure the top edge of each rib is flush with the top edge of the spar. Ribs should fit snuggly. Use a
triangle ensuring the ribs are vertically straight and in the correct position. Using some wood glue secure the ribs to the spar. Take your time. See photo below Note - the nose ribs 5.210 and 5.208 are thinner than the main ribs. These nose ribs will use a thinner rib cap than the ribs. This is per design. To help support and align the nose ribs to the front spar part 5.211 was designed. Use these support pieces to position and hold the leading edge dowel 5.97 in place in the next step. Cut the dowel 5.97 into two pieces 13-3/8-inch long. The leading edge (dowel) goes from the root rib out to rib 5.207 where meets the front outline 5.114. Using support pieces 5.211 secure the dowel in position on the plans. Add the nose ribs using wood glue to secure to the front spar. Ensure the nose ribs 5.208 are position correctly before gluing as well as the main rib nose ribs 5.207 and 5.115 align with their main rib. See photos below
Position and glue the front and rear outlines 5.114 and 5.30. Make sure they follow the outline shown on the plans. Glue the outlines in position trim/sand as needed. See photos below
Cut four 2-inch pieces of 5.122. Glue these on top and bottom of rear outline 5.30. These will butt up to the spar. Sand these support pieces to a taper from the spar down to rear outline. At the same time trim and sand the spar ends. See photos below
Position and glue nose ribs 5.209 and 5.210. See photo below Remove the stabilizer from the building table. The two leading edges should line up when you look down the stabilizer. See photos below
Time to add the rib capping. Rib capping will go onto every rib and nose rib. The box rib covers 5.117, 5.118 go in place after the rib capping. The main rib capping starts at the leading edge over the front spar stopping on top of the rear spar. It will be trimmed to be flush with the back spar edge. The nose rib capping starts at the leading edge stopping on the top of the front spar being flush with that edge. You will notice on the plans that the main ribs use a wider rib cap than the nose ribs. Try not to mix that up. The rib capping is very visible so start on the bottom first. Use material 5.116 for rib capping the main ribs first. Try using paper clamps or similar helping secure the rib cap to the rib. Use wood glue. Keep the rib cap straight. Start at the leading edge and work your way to the rear spar. You can trim the rib capping when it s dry. Don t get happy with glue. See photos below Once you have the main ribs rib capped go ahead and do the nose ribs. Use material 5.45 for these nose ribs. Again start on the bottom and follow the same procedures as you did for the main ribs. See photo below -
Repeat the two above steps for the other side of the ribs. Once you have all the rib capping done. Trim the ends flush with the spar and sand the front so it blends a little into the leading edge. Add the box rib covers 5.117, 5.118 now. Reference the plans for the locations gluing these covers to top and bottom of their respective ribs. Note that the outer cover 5.118 does not go to the leading edge. It is flush with the rear spar and goes a weebit past the front spar. This is per design. See photos below -
Stabilizer Fittings There are sixteen steel fittings involved with the stabilizer. Four of them attach to the outside (on top of the fabric). Those fittings are 4.12 (rear wire plate - 2 each) and 4.41 (front lower wire plate 2 each). These fittings will go on after you have the stabilizer, upper and lower vertical fins covered/painted installed on the fuselage and you have the flying wires available. The other twelve fittings are added prior to covering the stabilizer. Note it is recommended that you test fit the proper screw into the fitting hole ensuring the screw fits correctly. The fitting holes were design to create a snug fit. In the event you find a hole too snug for the screw, enlarge the hole by drilling it out some. Most likely the holes will be fine as tolerances on screws and clevis pins are pretty decent. Eight flying wires attach to the stabilizer. The front flying wires attach from the upper and lower vertical fins to the front spar fittings. The rear flying wires go thru the upper and lower vertical fins to the rear spar fittings. Technically, the rear flying wires set the incidence for the stabilizer. There are eight pulleys used. Four outer and four inner. Start with the outer pulleys. The pulleys need to be installed before the inspection window wooden frame goes in place. That way you can make any adjustments to that frame. There are four window frames upper and lower. Typically, the lower frame is just covered with fabric. The kit uses two upper inspection windows and the lower will be covered with fabric although you will install all four window frames. Modern SE5a replicas have updated the inspection windows to be removable. The kit does not follow that. The kit has the original application which is the inspection window is held in place with fabric. Recall these WW1 planes were designed for several months of use not years. If you want to gain access to the pulleys, then you would create a removable frame like the modern subjects today. A picture is shown below what is used today.
The pulleys 3.2 are visible thru the inspection window. They need to be painted aluminum as the originals were aluminum not black plastic. The inner pulleys are not visible so you don t have to paint those if you don t want to. The outer pulleys are visible and should be painted. At this time spray paint the four outer pulleys aluminum. Each outer pulley 3.2 uses a pulley arm bracket 4.57. There are two pulleys in each inspection window. The upper pulley guides the cable 6.48 to the upper control horn and the lower pulley guides the cable to the lower control horn. The pulley arm bracket 4.57 is steel which will be bend/formed/soldered and painted. Gather up four pulley arm brackets now. Using a pencil draw a line in the center of the bracket. Using a 1/8-inch rod or drill bit put that into a vise then bend the bracket evenly around that rod. You can use some pliers to get a nice bend around the rod. Ensure that the bracket holes align. Repeat this step three more times. See photos below
Each pulley bracket will need a copper guide (tube) 6.42 solder inside which holds the bracket in place when installed. Take the copper tube place it inside the bracket seating it all the way down centered and straight in the bracket. Hold these parts in a vise ready to be soldered. Repeat this step three more times. See photos below Solder the copper tube to the bracket. Don t get too happy with the soldering just enough to secure the tube in place. File / clean-up the solder joint if needed. Repeat this step three more times. See photo below
The bracket arms need to be widened a little so the pulley can spin without hitting the bracket. Place the bracket with the soldered tube in a vice using a piece of 1/4-inch thick steel or even some hardwood widened the bracket arms out. Repeat this step three more times. See photos below You should paint these bracket arms satin black now or leave you can leave them natural.
You need to add some wood to the top and bottom of the front spar before continuing with the fittings. The inspection window needs a solid surface to attach to. You will add some wood 5.122 in-between the rib capping next to the box rib plywood cover 5.118 above and below the pulley fitting area. Cut eight pieces gluing in place where this filler wood is flush with the leading edge of the spar. See photo below The pulley bracket arms are held in position with the double pulley bracket 4.59. This flat bracket needs to be formed into a U shape bracket. Which is not all that hard. The goal is to ensure the holes align with each other. Even if they are off a wee-bit that won t be critically bad. See the before and after photo below The gap should be around 1/4-inch. You want to pulley arm bracket 4.57 to be able to move freely and the holes to align straight. Using a pencil mark the two bend lines centered about the center hole. Bend the fitting 90 degrees creating the U shape. See photo below
This fitting can stay unpainted if desired. Otherwise, you should paint it satin black now. The front spar 5.111 has a pre-drilled hole locating this fitting. Note that once this fitting is installed it will require cutting fabric to gain access to it. Using screw 6.11 temporally install the fitting in the spar. Make sure the fitting seats well and the screw head is in-between the fitting ears. This same screw will be used to secure the wire plate fitting 4.40 which is mounted on the other side of the spar. See photo below
The front wire plate 4.40 needs to be painted satin black after you form the fitting. This wire plate connects to flying wire E shown on the table plan sheet 4. You will make a left and right version of this fitting. The tab or ear that connects to that wire is above the fabric and is bent slightly backwards. The bend starts at the top of the filler wood 5.122 towards the elevator. The tab or ear should be pointed to the fuselage. The fitting is secured using screw 6.11 with hex nut 6.10 and screw 6.2. For now, test the fitting in place. See photos below Mark the fitting where it clears the top of the filler wood 5.122 remove the fitting and slightly bend the tab or ear. Once painted you can permanently add this fitting using the hex nut and screws. Use some Loctite (blue) on the screw and hex nut keeping this hardware secure. See photos below
The outer pulleys are next. You will make a right and left set, two of each. The upper pulley near the inspection window should have the hex nut 6.5 on top when you look through the inspection window down at the pulleys. A copper eyelet 6.22 is used to help the pulley spin freely. The top pulley should have the top of the eyelet facing the inspection window. The lower pulley should have the hex nut and eyelet flange face the bottom window. When the two pulleys are installed into the bracket the screw heads should be in the center with the hex nuts on the outside. This assembly should be permanent so add some blue thread Loctite (blue) to the screw threads when you assemble the four pulleys. Test them in place as well. See photos below Mount the outer pulleys to the base bracket 4.59 using screw 6.60 and hex nut 6.5. There is no advantage of which way to insert the screw. Use Loctite (blue) to secure the hardware in place. The pulleys should spin freely and the pulley arm should move up and down with no interference. See photo below
With the outer pulleys installed you can add the inspection window cross brace 5.119. You will add four cross braces; two top side and two bottom side. Reference the plans and photos below to understand how this brace is installed. Cut, notch and glue the balsa cross brace in place using wood glue. Notice the cross brace should be flush with the box rib plywood. There should be a gap between the cross brace and pulley. The top side will get the plastic inspection window 3.72 after you cover the stabilizer at a later time. See photos below The center of the stabilizer uses four more pulleys. You will notice several pre-drilled holes in the center front spar. The group of four holes guides the cables going to the elevator servo. The other hole is for the center double pulley bracket 4.58. That bracket requires another small hole that you will drill. Overlay the bracket on the spar aligning the bracket to the existing holes marking the other hole location. Remove the bracket and drill a 3/23-inch hole at that mark. See sketch below
Bend the bracket tabs 90 degrees similar to the outer pulley base bracket 4.59 you did earlier. The gap between these tabs should be a wee-bit more than 3/8-inch which is enough for two pulleys 3.2 and their shoulder washers 3.62. Test fit the two pulleys and shoulder washers inside this bracket. The washers should be installed in each pulley with the washer base touching the bracket tabs. Use the screw 6.68 and hex nut 6.63 to hold and align the pulleys. The pulleys should spin freely. See photos below
The bracket and pulleys do not need to be painted. This area is not seen when assembled. Once your satisfied with the bracket and pulleys undo the screw adding Loctite (blue) to the threads. Re-assemble the pulleys, brackets, washers, screws and hex nuts now. Set aside. The opposite side of the front spar has another bracket 4.42 which is called the pivot bracket. This bracket secures the front of the stabilizer to the fuselage which the stabilizer would pivot off when the incidence was changed. In our case the stabilizer incidence is stationary (not moving) although we are still using the pivot bracket. You will bend the tabs 90 degrees creating a 5/16-inch gap between them. That gap size, 5/16-inch is the fuselage vertical support width. You don t want the gap any smaller than 5/16-inch a wee-bit more is fine. At this time bend / form this bracket 4.42 into a U shaped fitting. Add the screw 6.11 and nut 6.10 securing the double pulley bracket and this pivot bracket in place. As shown on the plans the screw head shown be at the base of the pivot bracket. That screw has a low profile which will clear the fuselage vertical member when the stabilizer. The opposite is true with screw 6.8 and hex nut 6.5 that screw head should be at the base of the double pulley bracket. This gives you access to that hex nut. At this time assembly these two fittings using the screws and nuts per the plans. Again use Loctite (blue) on the screw threads. See photos below
The remaining fittings 4.12, 4.41 and 4.50 will be added after the stabilizer is installed into the fuselage. The inspection window 3.62 and leather exits 9.3 will be added after the stabilizer is covered. The elevators should be installed before the top of the stabilizer is covered but after fitting 4.12 is installed to the rear stabilizer spar. To keep the cables in place on the pulleys you should use some small eyelet screws in random areas. These are not in the kit as you might want to use a different method than that.
You should cover the bottom and back spar with your fabric of choice now. It should remain natural and unpainted. The prototype used natural linen with clear nitrate and butyrate SIG dope. See photos below This concludes the stabilizer instructions. The remaining fittings, etc. will be discussed in other instructions.