Fuselage / Tail
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Jump To: Getting Started Wing Fuselage / Tail Radio / Balance Flying / Tuning Parts List Options Cores and More... *** Updates ***

[Courtesy of Bill Grenoble (iflyicrash "at" aol.com), Denny Maize (rcsoarnut "at" aol.com) and Joel Foner (joel.foner "at" fonerassoc.com), this page last updated on June 07, 2003]

Fuselage Overview

The Terminator uses a simple pod and boom design. The fuselage uses a minimum of parts, yet is quite strong. 

termfuse.gif (10054 bytes)
Dimensioned fuselage plan - click the small thumbnail image above for a large image.

*** Don't sweat the specific shape of the fuselage pod, as long as the basic dimensions in the drawings are adhered to.  Here's a picture with some experimental fuse pods we've built.  Just make sure that the length from the wing to the tail stays the same, the angle of the wing to the tailboom stays the same and there's enough space for your gear and it'll fly fine!

fusepods.jpg (43569 bytes)

But where do I get the arrowshaft for the tailboom? There are archery shops in most cities, and these shops carry a variety of arrowshafts.   Several types can be used for the Terminator. We have used arrowshafts from two major vendors, Beman and Easton. We use the Beman ICS 500 whenever we can find them - they are lighter and slightly larger in diameter than the Easton arrowshafts (less flex and lower weight). 

Note:  The standard Terminator tail boom, from the front of the wing saddle to the rear tip of the tailboom, is 26.5"-27".  (This is written up this way so that if you choose a different fuselage shape or design it is easy to get the overall tail length correct.)

If you cannot get the Beman, then the Easton ACC 328 or 339 will work (in order of size and weight - the 339 is the heaviest - anything lighter than the 328 is likely way to flexible).  Almost any carbon arrowshaft will do, although the smaller diameter shafts may take some extra work, and may have too much launch flex.  Some are very small diameter - these can be used, but the control wires may need to be run down the outside (CA the sheath in place every couple inches if you opt for this approach).

Create the Fuselage Sides

fusesides.jpg (32219 bytes) Fuselage sides with doublers (click for full-size image)

  1. Cut two fuselage sides from soft 3/32 balsa. Hold the two together and sand so they are exactly the same.
  2. Using the fuselage sides as a pattern, cut out two 1/64 plywood doublers. (these are best cut with household scissors)
  3. Making sure to make a right and left side attach the doublers to the fuselage sides with thick CA.
  4. Attach 3/16 or triangle stock flush with the bottom of both fuselage sides along the full length of the bottom using thin CA
  5. Attach 3/16 or 1/4 triangle stock flush with the top of the front 4" of both fuselage sides, using thin CA.
  6. Attach 1/8" square balsa along edge of wing saddle, using thin CA, stopping where the boom former will be installed.

Assemble Fuselage

sides_former.gif (58769 bytes) Fuselage in alignment jig (click for full-size image)

  1. Cut the center former from 1/8 light ply.
  2. Click here to download an Adobe PDF file showing how to make a very simple jig for aligning the fuselage (5 kB PDF). The braces for the nose former should be 7/8" apart; the braces for the center former should be 1 7/16" apart, and the holder for the rear of the fuselage should be 5/8" wide.
  3. Place the sides in the jig upside down and slide the center former into place making sure it is aligned properly with the end of the plywood doublers. Make sure that everything is pushed down squarely on the jig surface and zap the center former with thin CA to hold things in place.
  4. Make the nose former from 3/32 balsa and thin CA it in place

Add Fuselage Sheeting

sheetedfuse2.JPG (34487 bytes)  sheetedfuse.jpg (35115 bytes) Adding top and bottom sheeting (click for full-size images)

  1. Now you can start sheeting from back to front on the bottom of the fuselage using light 3/32 sheeting cross grained I use thick CA for this and make sure to glue full width on the triangle stock also as you will sand much of the corner away when you finish the fuselage.
  2. When the bottom is sheeted the fuselage may be removed from the jig and triangle stock fitted to the top from the center former to the nose former with thin CA.
  3. The first 4 inches of the top is then sheeted with 3/32.

Mount the Tail Boom

boommount1.jpg (34664 bytes) Fuselage ready for tail boom attachment (click for full-size image)

1. At this time you must cut the boom former from 1/8 light ply and glue it into position. Make sure to make the hole for the boom slightly oversize so that you have room to align the boom. MAKE SURE THAT THE HOLE FOR THE BOOM IS BELOW THE LEVEL OF THE FUSELAGE SIDE TOPS!

boommount2.jpg (36376 bytes) Tailboom in fuselage pod, ready for glue (click for full-size image)

2. Slide the tail boom into the former from the rear about 3/16 past the former. Holding the fuselage upright the tail boom will pretty much self center in the triangle stock. Sight from front to back to check alignment. The boom may be adjusted slightly if necessary since we made the hole slightly oversize. When you are satisfied with right to left alignment put a drop of thick CA on top of the boom at the former.

3. Now fill the space between the sides and the tail boom at the extreme rear of the fuselage with tiny pieces of scrap balsa so that it remains aligned right to left but can still move up and down.

boommount3.jpg (35542 bytes) Final fuselage pod and boom alignment (click for full-size image)

4. Turn the fuselage over and block the rear up so that the wing incidence angle is level with the workbench top. Now block the tail boom so that the top side (now the bottom side since we are upside down) is also level with the workbench top. When you are satisfied that both the wing incidence and the boom are level with the workbench top put a drop of thick CA on the boom at the rear of the fuselage to hold it.

Here's an alternate boom alignment method from Dan Griscom. Lay your fuselage side on poster board and draw just the top section containing the wing saddle and rear top of the fuselage to the end. Then, trace the center wing panel airfoil onto the wing saddle, just as the wing will be placed when the Terminator is assembled. Draw a straight line through the chord line of the airfoil (through the center of the leading edge and the center of the trailing edge), extending it about 12" beyond the trailing edge.

Tack the front of the boom to the boom former with a bit of CA, leaving some space for it to move around. Hold the fuselage and boom against your template, moving the boom up and down until it is parallel to the extended chord line. Tack the rear in place, pick up the fuselage, sight the boom straight, and finish glue.

boommount4.jpg (38094 bytes) Final boom lock-down with epoxy (click for full-size image)

5. Turn the fuselage right side up and re-check your right to left alignment. When satisfied that alignment is correct fill in the back of the fuselage around the boom with scrap balsa to form a dam. You now have a space between the boom former and the rear of the fuselage which gets filled with 5 minute epoxy mixed with lots of micro balloons (to keep it light) - this secures the boom to the fuselage. NOTE: Make sure to push this mixture down around the sides of the boom, etc. to get a good bond on the boom.

6. Cut the boom off at 26 - 27 inches from the center former.

Add the Wing Saddle and Wing Hold-Down Blocks

boommount5.jpg (110500 bytes) Adding wing saddle and hatch support (click for full-size image)

  1. The wing saddle from the boom former to the center former is doubled on the inside with 1/8 square balsa and thin CA.
  2. At this point the wing hold down blocks can be installed. The lower portion of the front hold down is 1/8 light ply and slides up against the bottom of the 1/8 square doublers and against the center former. The upper portion fits between the doublers and is located so the front wing bolt is about inch back from the leading edge.
  3. The rear hold down is constructed the same way and is located so the rear wing bolt is located 5 inches from the front one.
  4. The upper hatch is made from light 3/32 balsa. A small scrap of balsa may be used to make a locator block for the front of the hatch. For the time being the hatch may be held on with a small drop of thick CA to the center former. This will allow you to shape the hatch along with the rest of the fuselage.

Sand and Finish (almost done!)

  1. Now it is time to get out the sandpaper and shape to your liking. I like to round the corners pretty hard and make a nice aerodynamic shape. Carefully cut the top hatch loose and remove.
  2. When the fuselage is shaped to your liking, the whole thing is covered with a layer of fiberglass cloth (cloth between 3/4 oz and 1.5 oz works fine - 3/4 oz is strong enough to withstand being "piled in" from fairly high up!).  Lay the fiberglass over the fuselage and attach it with water based urethane, which acts as the finish as well. Allow this to dry overnight.   Don't skip this step - with the layer of fiberglass it is very difficult to damage the fuselage pod, and it doesn't add a significant amount of weight!

An easy technique for applying fiberglass is given in this CRRC tech note.

Here are alternate instructions for covering the fuselage (from Denny Maize, aka rcsoarnut "at" aol.com):

"When covering the fuselages with glass I clamp the fuse horizontally from the tail boom and upside down. I use a single piece of 3/4 oz cloth draped over the fuse. I use a foam brush to apply the urethane starting on the bottom and working down both sides (you will have to reach in with your scissors from the front and make a couple of slits to go around the nose contours). When I get the sides covered I stop and trim the cloth so that it will overlap on top. Rotate the fuse and work first one side then the other till they are overlapped and you have your first coat on.

"I do not make any attempt to blot this first coat, nor do I use spray adhesive as I like to get the saturation and penetration of the wood for strength. On subsequent coats where you are just filling the weave you can blot the excess off. This fuse is so small and light that I feel the good penetration for strength on the first coat is worth a lot more than the millionth of an ounce you might save by skimping here. My fuses weigh from 1 to 1.2 oz with the boom installed so I'm not sure what you would save by skimping. I don't think you will properly wet the cloth and wood with a spray can on the first coat, but, for finish coats it would be fine."

Option: tinting water-based polyurethane

Drill and Tap Wing Holddowns

  1. You may now locate the exact center of the wing center section and place the wing on the fuselage.
  2. Drill a 7/64" pilot hole through the front edge of the wing, about 3/4" from the leading edge - also drill through the holddown block and tap the block for 6-32 threads.
  3. Open up the hole in the wing to accept a 6-32 screw and install a 6-32 x 1" aluminum or nylon screw.
  4. Carefully measure and locate the wing by measuring from tips of center section to the center of the boom - make SURE that when you drill the rear hole the wing is in good alignment (both tips equal distances from the nose or tail.
  5. When properly located, drill rear hole exactly 5 inches from front bolt and tap rear block.
  6. Open rear hole in wing and install 6-32 x 1" aluminum or nylon rear wing hold down bolt.
  7. To keep the wing from being crushed at the bolt locations, make up a couple of "washers" out of 1/16" plywood, about 1/2" in diameter, and glue them to the upper wing surface with thick CA.  (These don't need to be round - we cut them 1/2" square and just sand or cut them to be "roughly round").
  8. If you want to be able to finger-tighten and -loosen the wing bolts, cut two 3/8" long sections of arrow shaft, sand the bolt heads until they friction-fit inside the shaft pieces, and then CA the shaft pieces in place.
  9. To make the threaded holes stronger, tap them, drip a bit of thin CA into them, wait a bit, and then tap them again.

When you want your next wing to match, screw a cut-off screw you pointed into the front hole. Push the wing down on it, making sure that it's straight, then remove the wing and drill up through the dimple mark. Move the cut-off screw to the back hole, hold the front of the wing down with a screw through your new hole, align the wing, and push the back of the wing down against the point. Drill up through this second dimple, add plywood washers, and you're done.

Install Throwing Grip(s)

Throwing grips are an almost religious topic in the HLG community.  Here are the approaches we've seen used for Terminator throwing grips:

  • 320 sandpaper glued to the fuselage sides, and add a brace to keep the fuse from getting crushed and use a "squeeze grip" to throw with
        (easy to install and use)
  • Install a 3/16" throwing peg at varying locations from the trailing edge to about 1.25" ahead of the trailing edge    (some feel this gives the highest throwing power and control, but you do have to be very careful not to pull down during launch or you can fold the wings!)
  • Cut a hole in the fuselage bottom for a throwing hole
        (a classic approach - requires adding a partial height former for your finger to push against)
  • Reshape the rear of the fuselage so that you end up with a finger-grip using the bottom of the fuselage (with a finger grip area just below the wing trailing edge).
        (inspired by the Orbiter HLG, provides an easy high power grip while avoiding the possibility of folding wings due to a pull-down during launch - but does require playing with the fuse design a bit) 

Probably the best thing to do is to talk to your local club members and pick an approach that seems to meet with local approval.

Build and Mount the V-Tail

The v-tails are of standard balsa construction. Some folks mount the v-tail to the top of the tailboom.  These instructions show mounting it under the tail boom. There are a couple of tradeoff's either way:

On top of tailboom: Less likely to get damaged from landings, since the tailboom protects the bottom of the "v"

Under the tailboom (described here): Allows control horns and linkages to be more streamlined (they don't stick out as much), so the drag profile of the tail is lower.   Easier to align.  Can be easier to damage, so you might want to put a light coat of glue or light fiberglass along the bottom of the tail "v" joint so that it doesn't get scraped during landings.

tail_surfaces.gif (6712 bytes)
Here is a dimensioned diagram of the tail surfaces (click for a large image).

tail_joints.gif (2863 bytes)
And here is a diagram showing the angle of the tail "v", as well as an illustration of the control horns and linkages (click for a large image).

Here is a picture of what the assembled tail looks like from above (click the thumbnail below for a larger image)
tailcontrolhorns2.jpg (7895 bytes)

Now for the step-by-step instructions (thanks to Dan again for this step-by-step tail construction guide). (Note: there are a lot of specific dimensions given here. Treat these as loose guidelines, any and all of which may be changed.)

  1. Cut the tail parts from 1/8" balsa. Use contest grade balsa (4-6 pounds); if not available, use as light as possible. (You can reduce weight by using 3/32 contest balsa with lightening holes, but the results won't be as strong.)
  2. Round the leading edge of each stabilizer and the trailing edge of each ruddervator, and bevel the bottom of the front edge of each ruddervator (see the diagram above if this is confusing).
  3. You want to join the roots of the two stabilizers at a 110 angle: with an 8" tail, the tips should be 13" apart. Using a long piece of tape between the tips to set this distance, tack the joint with thin CA, fill the bottom crack up with thick CA, and spray with accelerator.
  4. Cover the tail components with film (Ultracote Lite Transparent works well). Make sure to leave 1/2" of space on either side of the top of the joint on the stabilizers, so you can glue down the arrow shaft. Leave the edge of the ruddervators closest to the V-joint bare as well; this is where the control horns are glued. Be careful not to warp the tail when shrinking the film.
  5. Hold the stabilizer V against the bottom of the arrow shaft, overlapping the last 2 1/8" of the shaft and leaving 7/8" of the joint uncovered. (You may want to add shims at the front between the shaft and the stabilizers; see note below for details.) Tack in place, fill joint with thick CA, and spray with accelerator.
  6. Hold two pieces of 1/32" plywood between your fingers. Use scissors to cut both at the same time to approximately 1/2" high or a little less, and 1/2" wide. Taper one or both sides as you wish, and sand both while still holding them. Then drill a 0.040" hole through both.
  7. Temporarily tape each ruddervator to its stabilizer with two small pieces of masking tape, one at either end of the hinge. You should have about 1/4" space from the end of each ruddervator to the V-joint, and each ruddervator should be held at neutral.
  8. Hold one of the control horns with a pair of needle nose pliers and apply thick CA to the side you want to attach. Hold it against the inside edge of one of the ruddervators while sighting that you are not over center, and spray lightly with kicker with the other hand. Do the same for the other side.
  9. (In the radio/balance instructions, you'll run the control cables through the shaft and add Z-bends at the end to match the control horns. After bending the Zs, remove the ruddervators, put the Zs through the control horns, and reattach each ruddervator with hinge tape.)

NOTE:  We've found that if you add a little negative incidence to the v-tail (rear of the tail a little higher than the front of the v-tail), you'll need less shimming during the tuning phase.  In general, we set the rear of the v-tail 1/64-1/32" above the leading edge of the v-tail, although this is really done by eye.  "If it looks like it's barely at an angle it's probably about right" (like cooking - sometimes feel counts!).  This isn't critical, since you can always add a shim to the LE or TE of the wing as described in the tuning section - and most folks find over time that they like the incidence tuning slightly different anyway.  This is another setting that you shouldn't sweat too much - but feel free to put a touch of angle in here if you wish - just make sure to try the shimming experiments discussed in the tuning section regardless of what you do.

And if you really want to build a conventional tail...

Click here to download an Adobe Acrobat diagram of a conventional tail that works well on the Terminator (126 kB).

Jump To: Getting Started Wing Fuselage / Tail Radio / Balance Flying / Tuning Parts List Options Cores and More... *** Updates ***

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