Tail

For the Bubble top P47 we have included a dorsal fin that is punched along the bottom edge of the vertical tail section. Carefully cut out the diecut parts from the coroplast sheets using a Xacto knife or razor blade. Corogated plastic is very stretchy does not die cut cleanly.

I generally start with the tail group. Look at Fig. 1 for the position and a side view of the hinge line in the elevator. (Note: these instructions will refer to drawings that are included at the end of this manual). Find the approx. hinge line by slipping the elevator into the fin (or just hold it up to the fin and line the tab and slot up) and pick a rib that will allow the elevator to move up and down without binding on the clearance hole in the fin (on this plane about 5/8 inch at the center dip). After finding the rib where you want the hinge, slice only the bottom surface of the coroplast. Then trim the flashing off so the hinge will bend up and down without binding on itself. Then make dashed cuts in the hinge; this makes the hinge bend easier. I take an Xacto knife and make 1/2" cuts every 1/4" or so. Bend the hinge up and down a few times to loosen it up.

The tailpieces are glued together with GOOP (that’s the retail name - E6000 is the industrial name). A small bead along each side of the fin will do. Then block them so they will dry straight and perpendicular. Thick CA or 5min epoxy glue will work also but not recommended as it will not be as crash resistant. Silicone glue will work too but don't get it anywhere you will need to tape or glue. Set the tail aside to cure and start the wings. The dorsal fin will be fit to the tail section when the fuselage is completed and the tail group is installed.

Wings – before going on, decide which wing version you will use, find the wing tip pattern and cut out the corresponding aileron. The long aileron is for the long span square tip wing and the short aileron is for the semi-elliptical standard Jug wing.

Before making the wings you need to prepare the wings for the ailerons. Most of our combat war birds have tapered wings. Tapered wings tend to get thin at the trailing edge towards the tip. Our aileron stock is 4 mil (about 1/8 inch thick) coroplast. So before you start prepping the wings, you will need to trim and sand the trailing edge. Make it a constant thickness, root to tip, so that it will approximately match the coroplast material. Usually the root is at about the right thickness. If it is thicker than the aileron stock, sand it down a little first. Then use a straight edge and mark a line from the root to the tip so that when the wing is trimmed, the trailing edge is a constant thickness. In effect you will be making the wing trailing edge a little more tapered by maybe 3/8 inch at the tip. This is OK; we have sized the wing to take the trimming into account. For the ailerons to work efficiently and smoothly, the trailing edge has to match the thickness of the ailerons.

There are a couple options for sparing and joining the wings - read them both and decide which one you like better.

Split the wing jackets and sand smooth the ridge bumps that came from the spar pockets -- set these aside, you may need them later.

OPTION 1: The Jug wing is in two halves + center section and can be cut for at least two scale wing span lengths. First you will need to decide which plane you want to build. The shorter span pattern is the rounded wing tip pattern and will use the shorter ailerons. This will give you a span of about 41-1/2”. If you wish to make the longer span plane, use the squared off wing tip pattern and the longer ailerons for an approximate span of 44-1/4” Use the appropriate wing tip pattern for the wing tip shape and cut and sand both panels to shape. After the tip shape is cut, sand the bottom and top edges of the wing tip. That will eliminate the thick and ugly wing tip that shows up after cutting to the tip pattern. Sand the top and bottom surfaces of the wing and the center section smooth with 150 to 220 grit sand paper and dust off thoroughly. This helps the tape to stick. We have included a center section that has the dihedral cut into it. Check the dihedral for accuracy before gluing the panels to the center, sand carefully if they need truing up. Block the wing tip at about 2-3/4" from the table to the top surface of the wing tip, (see Fig. 2). After the dihedral is checked and wings are sanded, place a weight on the center section and only when you are satisfied with the dihedral, Use 5min Epoxy to stick them together. Very important: before the glue sets, MAKE SURE the wing panels and center section are in the correct alignment with each other. One wing panel can not be twisted in relation to the other wing panel or you will have a plane that will continually bank one direction or the other or that will have a nasty habit of snap rolling. NOT GOOD!

Installing wood spars…..

We have included spruce spars on this kit. The wings have a spar pocket cut into them already and will pretty well fit the spars. Because the wing is tapered, the spar pocket will get a little smaller at the wingtip so use a sanding stick or gently drag the end of the spar through the slot several times to open it up until it fits. We usually never have a problem jointing the spars at the center of the wing center section but use a scarf joint in the middle of the center section for a stronger joint. Make a scarf joint like this: overlap the sticks and scarf the ends off so they overlap smoothly and create a larger joint area. The dihedral joint is not a problem, we usually sand the spar groove a little deeper through the joint and into the center so the spars will join in the center without making too big a bump – this is only a problem on the bottom of the wing as the top spars will naturally intersect each other slightly below the wing surface. Or you could crack the wood slightly and bend to match the dihedral angle joints - it will toughen up again when the spar is glued in. Sand the ends of the spars to match the wing tips that you just contoured.

OPTION 2: Split the wing jackets and sand smooth the ridge bumps that came from the spar pockets. Prepare the spar slots and check the dihedral with the center section as above but do not glue the wing panels to the center just yet. When satisfied that the dihedral is correct, cut the spars to fit each wing panel and cut a short piece for the top and bottom of the center. Sand the ends of the spars to blend with the wing tip shape and the sand them flush with the Root end of the wing. Cut and sand the short sticks for the center section so that they are flush with the dihedral angle. Now glue the spars in using one of the glues mentioned above. After gluing the spars in, tape them up as outlined above, including the center. Cover the wing panels with wax paper and use the wing jackets to hold the wing panels straight and contain the urethane glue if used. Stack the wing panels and weight them until cured. Urethane and wood glue will take over night. Epoxy is considerably quicker. After the spars are cured, then glue the center to the wing panels with epoxy as outlined above. You can use strips of strapping tape to hold the panels together as the glue cures. After the panels are stuck together, glue a 1” wide strip of cloth or fiberglass with some epoxy along the wing joints on the top and bottom. After the joints cure, you then attach the ailerons and finish taping the wing.

  There are other ways to do wings and no doubt you have a favorite, so by all means use what works for you and experiment a little. That’s what makes this hobby so fun.

The ailerons are die cut and I will assume you have already decided which to use – the long or short ones.

Center the fuselage on the wing and, at the trailing edge, make a mark about a ¼ inch from the side of the fuse. This is where the ailerons will start and should give plenty of clearance for aileron movement. If you get them all done and they end up too close to the fuse, they can be trimmed a little. First look at Fig. 3 for a visual aid on how to hinge the ailerons. Set the wing flat on a table, topside up, and lay the aileron along it lining it up properly with the wing tip. Use three tiny pieces of packing tape to hold the aileron and wing together with about an 1/8-inch gap between them. Lay a strip of colored packing tape along the top of the trailing edge of the wing and aileron together to create the top “hinge”. Flip the aileron up and lay it back on the top surface of the wing and use a small piece of tape to temporarily hold the aileron in that position, which will leave your two hands free for the next step. Stick a strip of tape along the backside of the aileron, smoothing the tape down and around the back edge of the wing – then smoothing it around to the bottom surface of the trailing edge. Open it up, lay the aileron flat. Turn the wing upside down and use a blunt object (window screen tool works perfectly) to press the top and bottom tapes together to complete the hinge. Do this to both ailerons and after they are attached, double check the aileron position relative to your wing tip shape and sand the wing tip a little or trim the aileron a little to match everything up. If this is difficult to figure out, see our web instructions for step-by-step pictures. The main idea is for the top and bottom wing tape to form the hinge by sticking them together between the aileron and trailing edge of the wing. This makes a very strong gapless hinge.

Taping wings

When covering wings with packing tape, follow this simple taping convention: Always start at the back and work forward overlapping about 1/4". This way the tape edges will flow with the wind instead of pointing into the wind. Another good idea is to always start with the bottom of the wing so that the finished wing always has the top tape wrapping over the bottom surface. It just looks a little neater. On tapered wings, cover one side at a time starting at the aileron hinge.

I like to see several layers of tape covering from the center of the wing out a couple inches past the wing joints. So, on tapered wings start applying the tape just ahead of the aileron hinge. As the tape comes across the center of the wing, let the tape run past the farthest wing joint from the panel you are working on. When both sides are covered you will have at least two layers of tape over the center portion of the wing. Again, always apply the tape from trailing edge to the leading edge with the typical ¼" overlap. The leading edge should have a couple layers of tape wrapped around it by the time the top and bottom covering is done. We recommend adding another layer or two of tape to the leading edge for extra protection. Stretching the tape modestly while sticking it down will help it go on smoothly but be sure to balance the stretching or you could have a wing that bends up or down.

After the main wing taping is done, apply one more layer of colored tape to the center of the wing. Start with the bottom and apply a strip from the leading edge to the trailing edge (front to back) in the exact center of the wing. From there apply more strips of colored tape with about a 1/2 inch overlap until you get past the seams about 3 inches both ways from the center. Pull these strips snugly and let the end of the tape run over the leading edge of the wing about an inch. Stop the tape at the aileron hinge because it will stiffen the hinge too much if you double the tape on the hinge line. This will give a couple more layers of tape right at the wing joints adding a lot of strength to the high stress areas right next to the fuselage. Do the same to the top surface of the wing and you will have a completed wing ready for the servo.

This servo works great if placed about 4-7/8" from the back edge of the wing to the servo pivot arm point.

Now that the wing is done, it is time to set up the aileron servo – see “Servo installation Tips”.  Find the exact center of the wing and make a centerline. Refer to the fig 3, for an approximate location. I usually place it at about 1/3 of the chord from the trailing edge of the wing. On the Jug, a standard servo will work fine but to save weight a Hitec HS81 will work well and the metal gear HS 81 is even better. Hold the servo in position and trace around it. Use a sharp knife to cut a pocket for the servo. Make it a tight fit. The wing is thin at the servo point so the servo will probably hang out the bottom surface of the wing. No problem, you can relieve the under-wing belly a bit to clear it. Install the control horns and connect the servo arms with the ailerons using the piano wire provided. I like to use Z bends at the ends and make a kink in the wire for adjustment. We have pushrod connectors available in packages of two or four which allow the use of only one Z bend with the straight end clamped to the control horn for easy adjustment.

The control throws for the ailerons should be 1/4” to 3/8 inch up closest to the fuselage. This will make the plane handle quick but fairly easy to control at high speed.

After the servo is cut in and you are certain of it's placement, slide it out for a second, coat the edges of the foam pocket and under the mounting tabs of the servo with silicone and slide it back in place. Wipe the excess off and be careful not to get it on the fuselage or wing where more tape would go. Set the wing aside and let’s build the fuselage.

Before proceeding, you need to make a couple of decisions. The Jug kit is a bit different than our other kits in that you are furnished with parts to build it one of several different ways. The two main variations of the Jug were the Razor back and the bubble top versions. We have included a standard Sig 9” canopy and a dorsal fin for the later bubble top planes and you should also find a wedge shaped canopy of foam to use for the razor back version. You may have already made your decision by the wing version you made but with the bubble top version, you could use either the short wing or the long wing and still be combat legal.

First, cut out the fuselage doublers and keep handy, as you will use them to check the motor position.

Fire wall with clearance for the muffler

Note: this is one of the prototypes that had the integral canopy cut with the fuselage. All production versions have clear vacuum formed canopy for the D and later versions and a foam canopy section for the razor back version.

As you sand the fuse you will want to shape it to blend with either the bubble canopy or the razor back canopy. If you use the clear bubble, locate the paper cockpit template and cut it out. Center it over the area with the flat at the front on the first angle cut into the top of the fuselage. Draw a line around it. This is the floor of the cockpit and the canopy will be positioned directly over it. When sanding the fuselage, round it out to the degree you wish but leave the floor of the cockpit flat by only sanding up to the line you drew around the pattern. The firewall area should be sanded as outlined above but go ahead and sand the sides sort of rounded until they curve in to meet the cockpit outline – leave the cockpit area flat, do not sand into it. Then, round out the rear of the fuselage back to the fin. The Jug fuselage is rather skinny and egg shaped at the rear from the canopy back to the tail so a lot of foam can be removed. Stop sanding when you are happy with the way the fuse looks.

Trial fit the fuse doublers to familiarize your self with their installation. The top edge of the doubler will be a little short at the canopy. This is no problem after it is all taped up. Trim the plastic at the front and rear of the canopy to fit well over the front, back, and sides of the cockpit. The trimming totally depends on how much or how little you rounded out the fuse, so trim a little at a time until you have a good fit. Check the Three view of the Jug we include with the kit and notice how the canopy is shaped and fit to the fuse. In general, not much plastic will need to be trimmed off the sides as the canopy on the Jug kind of swoops down low from the front and back giving it a “saddle shape” along the sides.

I used a band saw to rough the shape of the razor back but a sharp knife or large Snap Blade knife will carve it down quickly

For the Razorback, we have a paper template to approximate the footprint of the canopy. Line up the point at the front with the first angle cut in the top of the fuse, center it and trace around it to establish the razor back position on the top of the fuselage. Then do the same on the bottom of the foam razor back piece. This should give an approximate canopy shape that will fit up to the fuselage. 

Round out the fuselage up to the pattern line making sure not to sand into the flat where the razorback will glue on. I find it easier to sand canopies before they are glued to the fuselage so roughly carve the sides of the razorback and canopy section to the pattern line you traced onto the bottom. Then sand the sides smooth and slant them in towards the top of the canopy area. 

Study the three views sent with the kits for approximate canopy shape. The razorback and adjoining canopy are fairly pointed along the ridgeline. 

After you are satisfied with the basic shape of things - slice the canopy section from the razorback as per the drawing in fig # 5 and set aside. Glue the razorback onto the fuselage and use fine sandpaper to finish sanding the fuse and blending the razorback into the fuse. 

When gluing the razorback on the fuse, do not collapse the fin slot. The fin has to be able to slide under the razorback and into the slot after the fuselage is taped up so check the fit at this time – you will need to open up the slot a little on the rear of the razor back to allow the fin to slide all the way forward. 

On the real plane the razorback portion is actually slightly concave from about the rear of the canopy to the fin so you could sand that in at this time. The front wind screen of the canopy was kind of a rounded “V” shape with a metal frame at the center post. Trial fit the fuselage doublers. The top edge will sort of define the bottom of the canopy when lined up with the wing saddles. If it seems too short it’s due to how much or how little you rounded the fuse and is no problem, ignore it. We will install the doublers after the tank and throttle servo is in.

The fuel tank is laid out and cut in at this time. I like to go in from the left side of the fuselage, at about the center line, and dig a pocket that fits the tank snugly with about a 3/8 inch of foam left behind the firewall for strength and cushion in case of a crash. I like to crowd the tank close to the left surface of the fuse to give me a little extra foam on the right side to make a tunnel for the throttle servo linkage without accidentally boring a hole into the tank. Set the tank up so the tube on the left (as you face the front of the plane) is the vent tube that will go to the pressure fitting on the muffler. The tube on the right will go to the carburetor. One very important thing to do before installing the tank is to pressure check it for leaks and double check that the pickup and vent tubes are still properly placed. I pressure check by plugging one tube and blowing in the other. There are more sophisticated ways but this will quickly show up a bad seal or broken tank. If you put a leaking tank in the plane and fill it up with fuel, the raw fuel will eat out the foam on the front of the plane – not a very good thing – so check it before sealing it up.

You will have to accommodate the lines coming from your particular tank and a good way to help everything slip into place is to make the pocket long enough so that there is a little space for the fuel and vent tubes at the front of the tank area. After slipping the tank in, cut a chunk of scrap foam to wedge the tank in and keep it from sliding forward and possibly pinching the lines in a less than elegant landing. Locate and drill holes for the fuel and vent lines and install the tank. There is a lot of room for the tank in the Jug so a 4oz tank will fit nicely and a 6 oz tank would be OK too. After the tank is fitted and installed, start at the bottom and work up, covering the entire firewall with strips of strapping tape. Let the ends cover the nose back about an inch. This will strengthen the nose and help seal the firewall. Cover with another layer of colored tape over the face of the firewall letting the ends run long about an inch down the sides of the fuse. This will keep the foam from melting from the Goop glue we use when the doublers are glued and stapled on. Finally, put a couple dabs of silicone glue in the corners of the tank to hold it firmly in the foam.

You should now have a sanded fuselage with a firewall taped on and tank installed so the next step is to prepare the fuselage doublers for gluing on. These are die-cut from 2mil coroplast material and will cover each side of the fuselage from about the back of the wing forward and will be long enough to make the side of a cowl. If you miscalculate and get the engine a little to far back, it is easy to trim the front of the doubler a little to make it fit or cut it off and use a bottle to make a cowl - more on that later.

To prepare the doublers you could do two things – both of which are optional. The first is to use a blunt object and score the ribs on the inside of each doubler to help them conform to the shape of the fuse, and the second is to locate and cut a trap door on the side that you cut the tank in for access to the tank later on (that would be the left side if you cut the tank in on the left). Cut the door on only three sides so that one of the ribs in the coroplast will make a built in hinge. Cut the hinge just like you did the elevator hinge so the door will open out. Scoring the ribs does help the fit and is a definite plus, but lately I have not been using a trap door for access to the tank because it makes a stronger nose. If I have a tank problem, I just do a little surgery and open up the side of the fuse. Be careful where you cut though.

Throttle servo – Here is a good tip. Before gluing the doublers on, locate the throttle servo position and install it in the canopy area and route the throttle linkage through the foam. See fig. 2. There is a load of room in the Jug canopy so I installed the servo in the front right corner with the servo pivot at about 9-1/2” from the front of the firewall. I recommend using a sub micro such as a Hitec HS 55 or FMA 80 or similar for weight and space considerations. Temporarily screw the engine onto the firewall with a couple of screws and drill a hole for the throttle linkage so that it is inline with the throttle arm on the motor. Before cutting the pocket for the throttle servo, you could drop the floor of the canopy a bit where the servo is so the servo arm won’t hit the bottom of the canopy (razorback) or interfere with the bubble canopy. I gouge out an area large enough for the servo to fit plus room for the servo arm to swing. Then pocket the servo into the fuse – for directions on servo installation see ”Servo Installation Tips” further along in the instructions. The Jug fuselage is wide so you will have to sand a deep groove into the right side of the fuse for the throttle linkage to lie in – be careful not to cut into the tank!! Line up the groove to the throttle exit hole in the firewall and with the servo arm in the cockpit. Set up and install the cable and secure it in the groove with a couple dabs of silicone glue or spray glue if you made the slot snug enough. I wouldn’t glue the servo in until the whole system is checked out and in working condition but you could temporarily hook up the throttle and set up the lengths and throws before removing the engine and finishing the fuselage.

Use 77-spray glue and spray the fuselage doublers and the fuselage. After the glue dries and you are ready to install them, run a bead of Goop on the edge of the sealed and taped firewall. This is optional but the Goop creates an incredibly strong joint between the doublers and the firewall. When you are ready to put the doublers on, very carefully line them up to the wing saddles before sticking them to the fuse – you only have one shot at it because the glue will stick so make sure it’s right before you stick them. Now you will see why you scored the inside of the doublers. They should conform nicely to the contour of the sanded fuse and if you have let the contact cement dry well, should mold themselves to the nose, a Monokote iron can be used to heat and shape them to the foam if you wish – but don’t get them too hot.

After the doublers are on, check the fit of the canopy. The fuselage doublers and the foam fuse define the bottom canopy line pretty well. If you used the clear canopy, it should fit over the sides and snugly at the front and back. If you did the razorback version, you may need to sand the canopy a little bit more for a good fit. It may need to be hollowed out a little to clear the servos and radio before covering it with tape.

This would be a good time to double check the engine fit and location. Check the clearance for the prop/spinner and front of the cowl. Before you can do that you may have to trim the doubler to clear the muffler and you may have to punch a hole for the needle valve to poke through.

Here is the key to the outstanding strength of our planes...

After fitting the doublers and cowl fillers (if you used them), use a hand tacker or staple gun to staple through the coroplast into the edge of the firewall all the way around. This will make the firewall very solid and able to withstand unbelievable crash forces. If you don't have a staple gun, use 1/2-inch wire nails, upholstery tacks, or even thumbtacks. Just be careful that you don't drive them through the fuel lines that should be already pulled through the firewall.

Wing Saddle.  Before proceeding with the taping you will need to remove the belly part of the fuse under the wing. This is cut loose on one end already so use a very long and sharp razor knife and slice it off at the back edge. Set the piece aside for covering later.

Before proceeding with the taping, spray another light coat of 77 spray glue over the foam part of the fuselage and let it dry.

The second major key to the strength of our planes is to wrap strapping tape around the nose from the firewall back to the canopy. Do the same on the under belly from the wing saddle to the firewall. Lay the strips side by side and pull them hard enough to cinch the coroplast down tight to the foam. I use long enough strips to go over the top and down the sides about an inch then turn it over and do the belly the same way. I like to do the same thing with the wing saddle. Lay strips of strapping tape side by side and cover the whole wing saddle and let the ends run up the side of the doublers about an inch. Pull these tight as you put them on too. 

When strapping tape is wrapped radially around the nose and wing saddle, you will make the nose of the plane virtually unable to crush or buckle.The strength of this construction will be evident on the first ground plant.

Now we are ready to start covering the fuselage with the colored packing tape. Curved and rounded surfaces, as found on Jugs and most other war birds, can be a bit of a challenge to the first time foamy builder. My first bit of advice is to relax and don't stress out about a few wrinkles. We really don't care too much about how it looks because these planes are designed to maximize fun, take extreme punishment, and then throw away! Now, that having been said, with a little care, a few tips, and experience at sticky-tape handling, you will be able to turn out a reasonable looking product also.

The place to start is at the wing saddle. You should already have strapping tape covering the saddle from side to side so now we want to cover it with the color tape. Start at the trailing edge of the saddle and lay packing tape across the saddle letting the tape run up the side of the doublers an inch or so. Keep laying in strips of tape with about a 1/4 inch overlapping the preceding strip until the saddle is completely covered.

If your plane will use the doublers to make the cowl, it is a good idea to let the tape run long enough to tape around the front of the doubler to cover the inside of the engine compartment all the way back to the firewall.

You should have the fuselage covered pretty well by now. Since you have the canopy off your plane, let the excess edges of tape wrap into the canopy area. You will have to slice it to get to stick smoothly. Check the canopy fit to see if taping changed anything, sand the canopy (razorback) a little if needed.

Cover the underbelly of the wing and the razorback canopy with tape and set aside. For detailing purposes, I like to spray the razorback canopy with “Dull Aluminum” Krylon spray paint after it is covered with tape. Spray paint sticks pretty well if you sand the shiny tape surface with 220 grit “wet/dry” automotive sandpaper. Then use automotive pinstripe to apply the canopy frame lines.

Note: this is the Bubble top fuselage with the dorsal fin added. Cut a little slot for the tab to fit into and use a dab of Goop to stick it to the fin coroplast. DO NOT put Goop into the slot as it will MELT the foam. I use a small fillet of glue along the side of the fin so it sticks to the tape.

At this point you should have a fuselage that is completely taped up. The tail group should be dry and ready to install now. I use a coat of 77-spray glue on the part of the tail that slips into the fuselage. Now, you have to be fast so have the slot in the fuse open (slice along the covered up slot and push the excess tape into the slot) and ready to receive the tail group. Then, quickly spray a wet coat of 77 glue on the parts of the tail that fit into the fuse. Before the glue starts to set, slide the tail into the slots of the fuse. Make sure the fin is straight and true with the centerline of the fuse and that the horizontal tail is laying flat on the saddle then squish the sides of the fuse onto the fin. If you are not careful, it is easy to give your plane a permanent right or left turn by bending the back of the fuse one way or the other. The goal here is to assemble the tail group and fuse while the glue is still wet to allow a little slippage so they can be aligned properly---good luck, work fast! An alternate would be fast curing epoxy. Apply a strip of packing tape under the fuse to close up the tail slot, then run a small bead of Goop on either side of the elevator to stick and seal the tail to fuse joint. Block the fuse and tail so they will cure in good alignment. We like Goop because it is extremely tough and sticks incredibly well to tape and coroplast.

Alternate Method: One of our customers suggested this – spray the inside of the tail slot with 77 glue and the under part of the fin that fits into the slot. Let it dry. Then line the slot with wax paper before sliding it in position. When it looks right – pull the wax paper out and stick the sides to the fin. Haven’t tried it but sounds like it should work.

Wing installation – fixed or removable???

Fixed. Find the exact center of the wing and make a centerline. Measure the width of the wing saddle on the fuselage and make parallel lines where the fuse should sit on the wing. Hold the wing to the wing saddle in the fuse and eyeball where and how much you will need to cut into the wing saddle for the servo clearance. Hold the wing into position and use a felt marker to draw an approximate servo arm and pushrod position. You will have to cut a hole in the fuse doubler for the pushrods to exit the wing saddle and there will have to be enough foam and coroplast cut out so the servo arms and pushrods will work without binding on anything. The hole in the coroplast will resemble a “T” shape with the vertical portion of the T to allow the fuselage to be separated from the wing and the top of the T will give the pushrods room to move back and forth. See fig # 2.  Try to remove only enough material for the servo arm and pushrod action as the more material is left of the wing saddle, the stronger the fuselage. Our web instructions show this very clearly.

It is a good idea to hook the servo to your receiver to check for correct and smooth operation because the wing will be glued on permanently very soon.

The radio gear will be mounted under the canopy so bore a 1/2 hole through the fuse to route the aileron servo wire from the wing saddle to the canopy area. Be careful not to drill the Throttle servo! Before the final wing installation, let’s get a handle on the balance point for the CG by temporarily assembling the plane and laying out the radio gear placement.

After the balance point is worked out, proceed with the wing installation. You should have the fuselage and wing ready for gluing together so trial fit the wing and double check that the servo works without binding on the fuselage foam or the doublers. If all looks well, put a couple dabs of GOOP on the wing saddle and stick the wing on. Sight down the fuselage and check that the wing is level with the horizontal stabilizer. If it isn’t, you could put a shim in one side of the wing between it and the wing saddle before the glue sets. Check the top view of the plane and see that the wing is square with the fuselage and centered exactly on the fuselage – use the reference lines you drew on the wing to help line it up. After everything looks perfect, run a fillet of GOOP along the wing to wing saddle joint on each side if the fuse. Block the wing up and weight the top of the fuse until the glue cures.

After the glue cures, you can stick the under-belly onto the wing, with 77 spray glue, to finish off the fuselage. The belly of the Jug may have a small gap due to the cutting process, which could be filled with a sliver of scrap foam. Coat the foam with 77 and finish with strips of tape over the bare foam sealing all the joints between the fuselage and wing.

Removable wings

We have punched dowel holes into the coroplast for those who would like to rubber band their wings on. Basically you would set up the servos and balance the plane, as above but instead of gluing the wing on, you would glue the under-belly to the wing and tape it up permanently to the bottom of the wing. You should also have thoroughly taped the cut edges of the fuselage that will mate to the belly portion when the wing is dropped into place. Insert 3/16” dowels of the appropriate length through the provided holes and use rubber bands to hold the wing on. If you are really tricky, you could set it up with wing bolts to mount the wing instead of rubber bands but you are on your own on that as it is out of the scope of how our combat planes are designed to be used. Personally, I think servos last longer on wings that are fixed solid. It’s up to you.

Final servo installation

If you haven’t done so, thread the wires through the holes and hook up the plugs. Now is a good time to center each of the servos (you should have already tested and centered the aileron servo) and make sure of the control wire lengths. Before sliding the servos in for the final time, coat the pocket sides with silicone sealer. This will hold the servo in place and the silicone is not too impossible to remove. Try not to get silicone on the plane because tape will not stick to it! If you do, wipe it off with mineral spirits (paint thinner). Tip: wrap the servo with tape so the silicone can be easily peeled off if you take the servo out. If you mount your servos externally, tape over the servos leaving the shank sticking out. I must stress again to make the servos fit snugly. If you want them to fit flush with the surface you are imbedding them in, you will have to create a pocket that is sort-of two stepped to allow for the mounting flanges on the servos. This will allow the servo to sink further in and will keep the control arm as close to the fuselage as possible.

This is the Jug all decorated for combat. The underside of the belly and wings were painted gray and the fuselage was painted with Krylon Hunter Green semi gloss. The stars and bars were drawn in a graphics program and printed on a color printer. The checker board is shelf liner paper from a local variety store. The canopy was painted silver and uses 1/8" black automotive pin stripe tape.

Well, the last things to do are install the engine and hook up the throttle, and install the canopy. You can leave the fuselage doublers to form a fake cowl or cut them off and make a suitable cowl from a plastic bottle. Look through the local grocery or variety store for a round or oblong container. You might have to start with a round bottle and cut and shape it a bit to get the “EGG” shape of the Jug. With a little creativity you should be able to fashion something acceptable. If you can find a bottle that is clear, it will be easy to trim openings for the cylinder head, muffler, and needle valve. Attach some little blocks (use Goop and tape) to support the back edge at the firewall.  Screw through the cowl, the blocks, and into the edge of the firewall with # 4 sheet metal screws. If you find a clear bottle, clean the inside of the plastic and scuff with steel wool before painting. Krylon works OK. It makes a pretty neat looking cowl and is very cheap and replaceable. I good tip is to use a fuel valve (we have those available for around $10) to fill the tank, I mounted it on a portion of the fuse doubler before cutting them off. Cut a little hole in the bottle cowl to insert the fuel barb into the filler and you won’t have to deal with the fuel lines every time you remove the cowl! 

The canopy can be painted gray or silver with Krylon spray paint and decorated with automotive pinstripe. I sometimes use 1/4 inch black pinstripe to hold the canopy on around the edge or you can tape it on with clear or colored tape and touch it up with silver paint. Some guys are gluing Popsicle sticks to the canopy and holding it down with screws.

You can decorate the plane with different tapes or decals. If you have a computer and a drawing program, make up some decals and stick them on the wings and fuse with spray glue then tape over them with clear tape. Sand the tape with 220-grit automotive sandpaper (black wet-dry stuff) and paint with Krylon spray paint. There are a lot of tans, greens, and grays that work well. “Dull Aluminum” color makes a silver plane but give it a couple coats of semi-gloss clear urethane before flying it. The clear is a good thing for a painted plane as it helps the paint resist the fuel. The paint will chip off and smear a bit but take a can to the combat and touch it up between heats – besides they start looking real when they get a little battle worn!

The main thing is to have fun with this plane. This is designed for a .25 to .40 size two stroke. A geared electric should work fine also. Flying is straightforward, she’s a large plane and I found that a square of course wet/dry sandpaper GOOP’ed to each side of the fuse, where I grip it for an underhand toss, helped me hang onto it when it was slippery from the engine oils.