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Stabilisator (Tail Plane)
Stabilisator (Tail Plane)
Standard Build - non removable
The parts are a little fragile, take care when extracting from the laser cut sheets, and take care when using. For example, it's easy to break the ply spars at the notches or to break off the rib feet. The stab is built, initially, in one piece on the template and then the elevator separated from the front part by cutting between the two ply spars.
The stab is built on the handy ply template. Make sure the template is flat on your bench - use some pins nailed through if need be to hold it all nice and flat. The template makes it very easy to line things up as the ribs have feet that fit into the template slots.
Ribs
Glue the central 4 ribs (S1,S2) together - use the ply template to align them correctly.
Insert (place) all the ribs into their slots - take care not to break the feet (use some CA to reattach as needed). Make sure they are all sitting down in the slots - use pins or tape to hold them down if needed.
Leading/Trailing Edge Ply (1mm)
Before gluing in the leading edge ply (1mm), test fit it and the LE balsa stick that will sit outside of it. You want the balsa block to mate primarily to the front of the ribs (the ply is only 1mm thick so hard to bind to that). So, you may need to deepen the slots in the ribs (for the ply) a little and you should sand the front of the ribs so that their profile matches that of the curved LE balsa stick. Use some 5mm shims to rest the LE balsa stick on when trial fitting. You will also need to trim the centre of the LE balsa sticks. So, only after convincing yourself that the LE balsa stick will mate with the front of the ribs, should you proceed to the glue in the LE ply.
Glue in the trailing edge ply (1mm). The rear slots in the ribs are delicate so take care.
Spars/angled ribs
Consider that the hinges will protrude through the front ply spar (but only into the 15mm square stick that will be glued to the front of the rear ply spar). So you may like to cut hinge slots in the front ply spar before you glue it in. It could still be done after, but it's much easier to do now. One hinge per section between the ribs is appropriate.
Glue in the two ply spars.
Cut to shape some of the 8x3mm balsa strip and glue in the two front balsa spars
Glue in the rear/central angled ribs (S6) using the line on the template as the guide for the angle. Block up the front of the ribs so that they are held in place when slotted into the rear ply spar. Glue in some wedges from scrap in the angle between the ribs and the plywood spar to provide some additional strength to the joint.
Cut to shape some of the 8x3mm balsa strip and glue in the two rear balsa spars. You may find you have to adjust the notches in the rear/central angled ribs to accomodate the spar.
Trim the 1mm trailing edge ply along the angled line of the rear/central ribs leaving an open wedge.
Remove the stab from the template and turn it over
Spars
Cut to shape some of the 8x3mm balsa strip and glue in the two front balsa spars
Cut to shape some of the 8x3mm balsa strip and glue in the two rear balsa spars. You may find you have to adjust the notches in the rear/central angled ribs to accomodate the spar.
Now remove the rib feet and do an overall light sand so that all surfaces are flat
Leading Edge Balsa
Reassess the fits of the front balsa LE stick. Make any adjustments you need to ensure the LE is mated with the ribs (and if possible, the thin 1mm ply).
Place the stab right way up and hold down securely with weights and pins - the stab may 'spring' a bit after removal from the template
Attach the two balsa LE strips. I used a combination of a) pins and b) pegs to hold the LE in place as the glue dried. If you don't feel you have a good mating of the LE to all of the rib tips or the 1mm ply consider gluing some little strips, top and bottom, to join the ply to the rear of the LE.
Separate the elevator from the stab by carefully cutting between the dual ply spars. After separation, sand off all excess.
Sand the balsa LE to a round shape. At this point, you need to try and fit the stab into the R3 part of the tail. You will probably find you need to adjust the contour of your LE near the centre, as the profile in the R3 is relatively slim.
Stab tips.
These are supplied as 8 sheet cutouts (4 front and 4 rear). You can either
Cut more from some excess sheeting (e.g. the packing sheeting) and laminate them into a block so that they are thick enough to match the tip rib.
OR
Treat the sheeting as the bottom of the tip and attach angled bridges to the rib (lighter)
Rear (x2) - elevator
Note that you are also going to glue on 15mm stick to the front of the leading edge of the elevator, and it will extend past the stab tips (joining with them). So the rear stab tips match the side profile of the elevator, before adding the 15mm stick.
Before gluing on, shape down the profile to be roughly correct.
The bottom of the ribs profile is flat, so pin/weight down the elevator so the ribs are flat against your building board (as it may have 'sprung' a bit after being separated).
Make sure all the mating surfaces are perpendicular (by careful sanding) and that when the 15mm stick is added, that it will also mate with the rear tip.
You might stick a toothpick though the rib into the tip as well for some extra join strength.
Glue on the tip - you can 1) attempt to correctly align with the ply spar or 2) have it extend just a little past the spar and sand back after.
Sand the tip profile to match that of the rib.
Front (x 2) - stab
All sanding can be done after gluing
The rear/bottom of the ribs profile is flat, so pin/weight down the stab so the rear of the ribs are flat against your building board.
Make sure all the mating surfaces are perpendicular (by careful sanding)
Glue on the tip - you can 1) attempt to correctly align with the ply spar or 2) have it extend just a little past the spar and sand back after.
Sand the profile to match that of the rib
Elevator Hinge Block
Pin/weight the elevator so it's flat on your building board, as it tends to spring up.
The 15mm square stick is going to be attached for the hinge block
You can either sand the profile to be roughly triangular if the hinge point is at the front of the stick or round if the hinge point is set back into the 15mm stick. It's up to you whether you do this before or after gluing it on.
I made mine triangular and arranged that before attaching. If you are just sanding it round, probbaly easier to do after attaching.
Glue on the 15mm square stick to the front of the LE ply spar, making sure it mates well with the rear tips. Be aware that the elevator LE ply spar tapers slightly to the ends (by about 1mm) when positioning the 15mm block.
Removable option - the stab is quite large, and you may wish to consider making it removable. Here is how I did it
Cut the stab in half at the centre rib. I did this with a hand razor saw, but you'd be better off with some kind of table saw
Sand the centre ribs at the cut if needed to make sure the faces are perpendicular to the rest of the structure. This is really not very easy!
Make a plug for the stab cutout in the fin. I made mine the same width as the platform I made for the stab to sit on (see fusealge build section) which is about 2cm. You can do this by laminating some balsa and you can get the right shape initially from the left-over ply that the fin section was pushed out from. Fiddle about to make this fit the best you can - it will eventually be glued in.
Don't glue anything in yet!
Select some tubing to join the two stab halves. I used a carbon fibre tube inside an aluminium tube (don't use aluminium inside aluminium as it will likely bind owing to molecuilar adhesion forces). The outer diameter of the carbon fibre tube is about 4.5mm. You want the inner tube to have just a little friction. We will use a pin to hold the two halves together.
One stab half and the central fin plug will receive the aluminium tube
The other stab half will receive the carbon fibre tube which will stick out of it long enough to go through the fin plug and into the aluminium tubes on the other half.
Drill pilot holes through the plug (taking great care with alignment) for where you want the aluminium tubes to go through. You have to work out those locations out by looking at the stab halves and where the tubes should be located.
Mine are centred about 3.8cm from the front and 3.6cm from the rear
Mark holes in the stab halves at the centre rib for where they will receive their tubes. Do this by aligning with the pilot holes you drilled in the plug.
Check all alignments frequently as the whole thing critically depends on this.
Drill through the center and first ribs of the stab halves to make the tibe recipient holes (remember the diameter is smaller for the half with the inner tube). Do this with an alignment method of your own devisement and a long bit!
Drill out the holes in the centre fin plug for the larger Aluminium tubing.
Now you are ready to test fit everything. Your goals of course are
to have the tubes exactly in the plane of the stab and at the same height
for the stab centre ribs to exactly meet the faces of the fin plug. It's not so easy to get all of this right, but mine was good enough (I did need to re-fabricate the fin plug).
for the stab to be perpendicular to the fin. I needed to add a small shim (1mm ply) to one side, on top of the fin plug ledge, to push one side of the plug up slighty.
Make and glue in (on the root rib side) some light-ply doublers for the second ribs sitting around the tube holes b
When you are happy it all works you can glue in (epoxy)
aluminium tube into the fin plug
the aluminium tubes into one stab half
the carbon fibre tube into the other stab
the fin plug into the fin hole
After it was all glued I found I needed to sand the carbon fibre tubes to ease their fit a little. Otherwise I would have no hope of getting them on or off once everything was covered (as you have reduced leverage points to hold things)
Create the locating pin holes to hold the halves together.
Close to the ply doublers, drill a small hole (about 1.5mm) perpendicularly down through the aluminium tubes
Now put the two halves together on the fuselage
Use a hand drill to drill through these holes through the carbon fibre tubes
Make a small (1cm) ply platform so sit on the top of the tubes - you will need to create some kind of support structure for it epoxied to the tubes - and epoxy it on.
Turn over and drill back though the holes though the ply platform.
You can just get a nail and bend it over at the top, to insert through these holes (with some tape over the top) to hold the two halves together.
These pictures are for the standard build
These pictures are for the removable stab option
Removable pins inserted through tubes.
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