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tucano 25.jpg

Well Lordy Lordy, it's starting to look like an aeroplane rather than a coffin! The front roughed out with the plane and coarse sandpaper. Needs finishing off but we're getting there.

Now I decided to make the Tuc an experiment - I've never used glass and Poly-C; so, with this being entirely a sheet structure, I'm going to have a go with that as the covering. Ordered some 0.6oz glass fibre cloth and a bottle of Poly-C. Should prove interesting one way or the other!

BEB

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I covered the fuse in my Acrowot this way, I found it easy to do and a lot less messy than Epoxy. Still looks good after 2years.

Acrowot

 

I am thinking of doing a Tuc build perhaps the same technique would be goo.

Edited By Glyn R on 30/04/2013 20:05:28

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Very smart indeed Glyn - that's the sort of finish I'd be very pleased to achieve. Did you spray the paint finish? Presumably you used a primer over the Poly-C after a light rub down with something like 400 grade - yes?

BEB

Edited By Biggles' Elder Brother - Moderator on 30/04/2013 21:55:15

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Posted by Biggles' Elder Brother - Moderator on 30/04/2013 21:54:49:

Very smart indeed Glyn - that's the sort of finish I'd be very pleased to achieve. Did you spray the paint finish? Presumably you used a primer over the Poly-C after a light rub down with something like 400 grade - yes?

BEB

Edited By Biggles' Elder Brother - Moderator on 30/04/2013 21:55:15

I used another coat of Poly-c and rubbed down then lots of coats of Hi-build car primer rubbed down between coats until there was very little paint left, the a couple of coats of Simoniz white primer on the white areas. I used 400 wet and dry on the first coats of gloss. All spraying just Aerosol cans.

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Hi, I have tried it but was a bit disappointed as I could pull off the fibre glass matting from the balsa test piece after the PolyC had cured overnight. I have since been told the balsa surface should be treated to a coat of 50/50 sanding sealer beforehand. So I will try again, Glyn has used it to good effect. I used 1oz fibre glass matting, may be 0.6oz will give better results.

Mike.

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Just a quick progress report.

I've fitted the nose ring and more or less finished the shaping of the fuselage - so that just needs the tailplane and fin adding to finish the basic construction.

I've fitted the aileron torque rods to the wings and covered them up. Tonight I joined the two wing halves - and the epoxy on them is setting overnight. I've used a bit less dihedral than Nigel specifies - just 25mm instead of 40mm. One delay here was that I removed the dihedral braces from the sheet when I was doing the wings. Can I find them? Can I hell as like! So had to make two new ones. No big loss as I might have had to make new ones anyway as presumably the ones supplied were for the 40mm dihedral set up. They might have been "fettlable" but let's say not, that way I don't feel so miffed about lossing them! Of course I will find them tomorrow we all know that! sad

So next up I'll fit the wings to the fuselage and then the tailplane.

I'll post some piccies tomorrow if I can. The weather forecast does not look good at the moment for tomorrow (I usually go flying Wednesday evenings) and the long range forecast for the weekend isn't so good either - so its looking like I should get some building done over the next few days.

BEB

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I promised a photo of the wings joined - here we are:

tucano 26.jpg

As you can see the aileron linkages are in now and the whole wing structure is quite stiff - nice design work Nigel!

Here is a couple of shots of a dry assembly of the wings to the fuselage with a spinner in place to check the lines of the nose,...

tucano 27.jpg

tucano 28.jpg

tucano 29.jpg

I've had a few issues with getting the line of the nose right. F1 seems to be considerably too small really. As I explained above I placed a ring around it to widen it a little, but even with this I wasn't able to get the lines smooth into the spinner. I have had to build up the front of the nose just a little with some filler - it surprising, but only a tiny amount really made all the difference and has made the front look much better. But I'm reasonably happy with it now.

Next I'll epoxy the wings on then it oonto the tail.

BEB

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Hi,

well the wings were expoxied in place last night and are now set. This morning I have glued the tailplane in place and the epoxy on that is setting now. Here's a photo with the clamps on the tailplane.

tucano 30.jpg

If any beginners are looking in just a word of caution about this step. Its vitally important to the flying characteristics of the final model that the wings and tailplane are spot on square and level. So do the wings first. Use slow setting epoxy. Loosely clamp everything up then take a piece of string and measure from the rear wing tip to the centre of the fin post on each side - it should of course be the same. If one side is longer - even very slightly - then that wing tip is need jiggling backward a tad. Then gauge again with the string to each side. When you're happy double check by using the string to gauge the distance from the front of the wing tip to the centre of the nose - again (as the fuselage is striaght) it should be the same each side. When completely happy tighten the clamps and do a final check that nothing has moved.

Now once that has set we can do the tailplane. Dry clamp the tailplane in position and view that model "nose-on" from short distance. Is the tailplane exactly level with the wings? If not you need to adjust the seat slightly. You might want to check by clamping a steel rule at different points along the seat that its the same all the way along.

Once you're happy the tailplane will sit level, apply glue to the seat and loosely clamp the tailplane in position. Double check its level. Use the string gauge technique to measure from the tips of the tailplane to the tips of the wings - the distance should be the same both sides - if not jiggle accordingly. Once completely happy its level and square tighten the clamps and do a final check.

BEB

Edited By Biggles' Elder Brother - Moderator on 11/05/2013 13:31:36

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No flying today, so a chance to do a little building. Been busy working on the tail today, once the stabiliser was in place its was time to add the fin, the first part of the strake and the side extensions to the front of the tail plane.

tucano 32.jpg

The trickiest part of this was getting the tapered blocks that extend the line of the rear fuselage along the fin. Carving, sanding and fitting so that they did extend the line of the fuselage was quite time consumming! There's a couple of close up views that show the tail from infront and behind:

tucano 31.jpg

tucano 33.jpg

More sanding and profiling to be done here but I'm pleased with it so far. I still have the very front of the strake to add.

I need to sort out a couple of things "mid-ships" next. First I'm wondering if I will be able to fit the three servos in the cockpit bay - immediately behind the battery? This would have the advantage of saving weight rearwards and save me making a hatch to access the radio gear - but it would be a very tight squeeze.

Secondly I need to make up the canopy. If I can get the servos in forward then I need to make a good canopy/cockpit removable hatch - that will start with fitting the canopy itself.

BEB

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You're not kidding WF!

OK starting to think about radio installation - where to stick the servos mainly. With a 4000mAh 3s in the front of the cockpit area and three mini-servos placed at the back, the model is tipping the scales at 2.35lb. So I'm optimistic of bringing it in at about the 3lb mark - which bodes well for the performance as the power train is spec'ed up to 400-420W.

The other good news is that with the kit in position she's still slightly nose heavy. There are no control linkages to the elevators and rudder yet and the coveriing will effect all that tail area - so that should pull the CoG back a little to just about the right spot with a bit of luck!

BEB

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I've decided to tackle the cockpit hatch next so I'll know for sure if I can get the servos into the rear of the cockpit area. I did consider getting the Vortex cockpit kit - but never got around to ordering it - so I'm making my own now. smile

To start with I'll need two 1/16 ply copies of formers F4 and F5. One of these copies is stuck to the original balsa version of the former and one copy is left as it is - as shown in the photo below with the doubled up balsa backed versions on the left.

tucano 34.jpg

The non-balsa backed ones are then fixed in place on the model. These will give me a hard sharp edge to the front and rear faces of the hatch hole, look neater and be more hardwearing than just the plain balsa faces. So here's the one at the front:

tucano 35.jpg

And the one at the back:

tucano 36.jpg

Obviously the tape is just there to hold it firmly in position while the glue goes off - (al a AW!)

The plan for the hatch itself is to use the balsa backed versions of F4 and F5 as end plates and run two lengthwise struts between them as shown in the dry mock up below:

tucano 37.jpg

The lengthwise pieces will be "let in" to the composite formers approx 50%. I'll put cross bracing pieces in this - from below. They will ;

  1. make it nice and stiff
  2. act as sideways locators to keep the hatch in position
  3. act as supports for a sheet balsa or lite-ply "floor".

Once lined up in place I will plane and sand the side pieces flush with the sides of the fuselage. The canopy will then glue to this framework. The edges being covered with some solartrim to finish it off. The hatch will be secured by extending the front of the floor to form a tongue that will slot under the ply F4 and at the rear I'll use magnets - the rare earth ones are very strong!

So, that's the plan let's see how it goes! All I need now are two 1/10 scale jet pilot busts - any ideas for decent ones? I've seen a few - but as my 17 year old daughter would say "they're pants"! Ideas gratefully received.

BEB

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Building the canopy hatch goes on,...

We have to glue the basic framework together - end plates and sides. I did this on the fuselage to ensure a good fit.

tucano 39.jpg

The pieces of card are temporary spacers to ensure that the canopy has just a little end clearence so that when the model is covered the hatch will still fit on! The cards give us about 1.5-2mm total clearance which should be enough. The cling film is too stop me accidentally gluing the hatch to the fuselage! Not good when you do that embarrassed.

Here is the basic framework lifted out of the fuselage once the glue was dry:

tucano 40.jpg

Now I need to fit the cross pices that will stiffen it and support the floor. Again these were fitted with the framework taped in place on the model. Its important to get these a nice "touch" fit as they will provide the side-to-side location for the hatch.

tucano 38.jpg

I'll leave all that overnight now for the glue to fully set. Next up is fixing in the floor and then sanding the side rails flush to the fuselage.

I have ordered my pilots today so hopefully they will make their way to me very soon and I can get on with doing the interior and getting the canopy itself in place.

BEB

Edited By Biggles' Elder Brother - Moderator on 15/05/2013 21:05:58

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BEB, enjoying watching your build.

Ref. suitable pilots, I used two jet pilots from HobbyKing. The ones I bought were item 9306000004, but these are on backorder, but, it looks like this is the same size 9306000034-0.

These are mine

img_4689_s.jpg

These look about the correct size, the only drawback is that being identical they are both looking in the same direction!

Cheers GDB

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We continue with the canopy hatch,...

I've cut the ply floor for the hatch. I did coonsider a balsa floor for lightness, but it would have had to be thicker than I wanted to get the required stiffness from the hatch. The hatch is not structural, but it is taken off and put on a lot, if its flimsy it will not survive the sort of handling my models get day to day - I don't intend this to be a hanger queen - I intend it to be a practical hack I can fly through the winter - so she'll have to be tough!

Here's the ply floor in place - not glued yet. The square cut out at the rear will house the fixing magnet. You can see the black plastic holder I have cut out to hold the magnet in the left of the photo.

tucano 41.jpg

Next I glued the ply floor in, added the balsa block that will hold the magnet over the square cut out and the ply tongue to the front which slides under the ply copy of F4. Here's a view from the top:

tucano 42.jpg

The small piece of metal to the right is a little piece of steel plate that I will let into a block glued into the fuselage and is the other half of the magnetic catch.

The view from underneath,...

tucano 43.jpg

And finally one of the hatch in place on the model,...

tucano 44.jpg

I still have a fair bit to do here. The side pieces need to be sanded to be just inside the upper lines of the fuselage - thus allowing the canopy itself to sit more or less flush with the fuselage sides. I need to add a little detail - nothing extreme, the pilots, tops of ejector seats etc., paint it all then fit the canopy. I have had a little trial fit of the canopy and the good news is it seems - as far as I can tell at this stage with the side pieces oversize - to fit very well. So hopefully no problems here - I hate doing canopies when they they don't fit well!

BEB

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Its drizzled all day and blown a gale - so a building Saturday,...

Fiddly jobs today. First I cut through the balsa block over the magnet cut-out on the hatch as I need to have access to the back. Then we insert the magnet into the plastic holder (having given it a rub over with some sandpaper to give it a key). The holder and magnet are placed in the cut out and positioned so that they are about 1mm short of being flush with the bottom face. Now we pour some epoxy into the hole - lovely job!

tucano 45.jpg

I have made a balsa plug that will seal this off once the epoxy is set and make it all look nice! Here's a view from underneath showing that the upper face of the magnet is sunken just a millimetre of so below the surface.

tucano 46.jpg

Next we make the fuselage side of the catch. A piece of 1/16 ply with a cut-out for the steel insert. This backed by a piece of balsa. The steel insert is then CA'ed against the balsa - again having been keyed - and again it is left a millimetre or so below the top surface.

tucano 47.jpg

Once the epoxy is set on the hatch part we can turn it over. Now the good bit! We add just enough epoxy to fill the space so the surface of the epoxy is flush with the surroundings. When you start adding the epoxy you have to spread it about to wet all the area you want epoxy to go in, after that you just keep adding it to the middle - blob by blob off a stick. I use Deluxe Materials slow epoxy for this and its quite runny so it forms a nice pool. Just leave it level to set!

Here's the hatch,...

tucano 48.jpg

(It my wonky photography that is sloping - the hatch is level!) Here's the fuselage fitting, having recieved the same treatment,...

tucano 49.jpg

Its hard to see the epoxy - and I'm I lousey photographer - but I'm sure you get the idea.

Why do it this way? Well when they're set the magnet and the steel are now encapsulated in a block of solid epoxy - just below the surface in each case. So the two cannot come out - impossible - and they can never come into actual contact - the epoxy is between them - so they don't "bang" together. Believe me these magnets are such that if we had a magnet-to-steel contact

  1. they'd be a swine to get apart and
  2. eventually we'd chip the magnet or damage the hatch.

This way we get plenty of magnetic pull without the harsh clash and no risk of losing either the magnet or the steel. I've used this technique in a number of models with sucess so far - let's hope it stays that way!

BEB

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