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Extra Super Bettini


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I made myself quickly a few rib drawings- this time using HQ W08 – which is slightly thicker. After making 5 sets for the stabilizer I am well trained so the rib designing / printing / ironing / cutting went quick without any bad surprises. Of course I used my proxxon FKS for all wood shaping where possible. This saw is so precise that you can try everything without glue (as shown here) and when you are happy with the set up you can glue it by using very thin cyano glue. 


I found some pretty hard 1.5mm balsa sheet in my collection which I used for the part covering of the rudder. Everything went very well, I was surprised about my own precision and the result looks like an ARTF rudder. It is very stable and I think it will withstand the wildest knife edge and snap attacks. This is one of the few occasions where I am really proud of my work.


I did not grind the rudder to final shape –I prefer to do this in the garden – and midnight is a bit too dark for this job. If I keep this building speed there is a chance that the bird will take off in 2011….

Next day: Did the necessary grinding in the morning as I had a late appointment some 80 miles away from home today. Next was drilling the wholes into the fuselage for the stabilizer support. As guiding tubes for the carbon rods which will fix the stabilizer halfes I used my toilet paper reinforced plastic tubes – or TRP…. (see further up this thread). Now it is time to put the whole tail together – which is problematic in my flat – as there is only one place which is big enough to allow putting the model on the floor without touching walls, wardrobe or bed… (removal into a decent size house planned for 12th of July - so no need to cry for VA’s space problems) After a bit of filing here and there I was happy with the position and fixed it by using a few drops of medium CA and kick spray. After that I disassembled the plane and glued the tubes properly into the fuselage using slow epoxy and glass cloth patches to reinforce the connection.
 
And this is how it looks so far

 

Edited By Vecchio Austriaco on 18/05/2011 08:43:17

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Has the family moved here now? In short have you now got a workroom and garden again. I was thinking that is quite a big model to build in a flat.
 
I used to work away from home and lived in a cottage, I found that difficult enough for space, although i did not aero model. I did build a Revell 1:48 plastic kit Bachem, to keep me amused, and was surprised how little space there was, above the necessities of daily life..
 
What ever, your persistence needs commending, as I have about 6 kits bought long ago, which I still cannot get around to building.
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  • 4 weeks later...
Hi there Vecchio,
 
I (like many other modellers) have a drill press but no lathe or mill, so my solution to holes in the ribs especially for reinforcing tubes, first I buy the brass tube of the same diameter I wish to drill, then I cut a section of the tube approx. 75mm and fasten (epoxy) the tube to a drill bit of the same inside diameter, alternatively you can use smaller tubes as sleeves inside the main tube, as long as the tube is still ridgid enough to hold firm in the drill press. Once that is done, I use a triangle fill to shape teeth into the cutting face of the tube, usually I can drill the tube hole through many layers of ribs up to say 12mm in total depth before I have to clean out the tube with a jewellers screw driver - a minor inconvenience for accurate holes
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Martin,
 
this is a good alternative which works for sure as well as the one discribed by me. I think part of our hobby is also to think what can be done by the tools and possibilities we have. And this leads sometimes to very good and practical solutions. I don't know if this method has alredy been described in the forum - if not it could be a good idea to make a picture of it and start a thread with the description of the method in it. I think there is a section containing hints and tipps which should be the right place. Cheers VA
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  • 4 months later...
Now that I said I am working on it in another thread I have to update it...
Fact is that I am covering the stabilizer and the rudder to avoid warping in my new shed...
As you see on the design drawing a bit further up the plane will be blue on top and white below. (of course with some stripes otherwise it's invisible.
Now I have some trouble with the tail wheel - may be some parts are missing from the original kit. As long as this is not fixed I cannot do the rudder.
Cheers VA

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Posted by Vecchio Austriaco on 31/10/2011 18:28:27:
.Sometimes I should read the thread title before posting. Even this is an old kit it is 20 years to young for your 2012 mass build actions....

Edited By Vecchio Austriaco on 31/10/2011 18:31:38

Edited By Vecchio Austriaco on 31/10/2011 18:38:16

Pity, it is certainly an impressive job you have done.

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Tail wheel trouble solved by making the part that was missing - I don't know if it was exactly this shape, but it must have been quite similar.
Its the lever which transmits the steering movement from the rudder to the axle.
Putting things together makes it easier to see it.
The brass part I am holding between my finger will go (180 degree turned around) to the rudder and will transfer the movement via springs to the wheel. The wheel itself I found in my bits box - may be I will change it after my past experience with foam wheels getting flat.
This means now I can glue the counterpart for the black steel spring (5mm birch ply) into the fuselage and tomorrow it is time to test fit the thing to the fuselage.

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I reinforced the rudder at the screw positions as the balsa is too soft to take reasonable forces.

A pice of soft ply did the job.
 
All the edges of the rudder have been treated with sand filler to increase the surface hardness. Works well, but at covering it gives a little sticky feeling.
 
Finally I covered the rudder and made a test fit of the rear wheel.

The little holes you see on the stabilizer are for the allen key to fix the stabilizer halves to the carbon tube. As I want to have the stabilizer removable I will leave the holes open.
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  • 1 month later...
Short time before this thread goes into its third year I will proceed a little.
 
Next thing to do are the wing servos.
The wing has been prepared by the manufacturer, there is a nice box milled out of the structure.

As you can already see from the pencil line it is not the size I need. I have purchased a servo frame when I bought the model, and this frame is unfortunately a little bit too short for the hole but much wider.
 
How to fix a servo into the foam structure? well - I thought some lining from 1.5mm ply would do the job. It gives you the surface to fix support structures and also helps to strengthen the wing in the area of the cutting.

Here the lining is already in place with some temporary spacers to keep it in the right position while the epoxy glue sets.
 
 

now you can see the lining. I am happy with it so far.
I use only the top of the servo frame, and make a 10mm light ply support structure below.
 
 

You can see now the support structure in place. As mentioned before the servo frame was shorter than the opening - so I had to fill the gap as you can see on top of the picture. The wire is just a pilot to avoid fiddling later with the real servo cable.
 
 

Now the whole thing is in place, the cover is flush with the wing surface and I am happy with this piece of work.

Edited By Vecchio Austriaco on 25/12/2011 11:42:21

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Nice work Vecchio, it's nice to see someone really take their time and doing a good job
Are you going to pull out all the stops to get it airworthy for the summer?
Retro models seem to be undergoing a revival, with PB organising another retro fly-in in April in Shropshire. This would be a nice change from the Tornados and Bullets that are bound to be present.
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The problem is that I throw the model into a corner from time to time... Otherwise it would fly already. And as it will be powered by a 45cc petrol I have to work to high standards as I have seen how these engines are shaking the models - so I rather work with belts and braces...
As I have no other project at the moment the Extra should be done by next summer. Speaking about retro - I hope I have my Curare by that time - it is an ARTF - but based on a model from the 70th. I should get it in March - but you know what promises of model shops are...
Now I will go to the fuselage - hope I can make the firewall today. But before it's dogwalking time...
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The dog had its walk, the Christmas dinner is in digesting stage so it is time to go on.
The original firewall consists of 3 parts - one of 4mm birch ply which fits behind the flange of the fuselage - one spacer of cardboard and one thin (2.5mm) ply of some strange hard wood.

As I don't like the idea of having some cardboard in my firewall I made a new pice of 5.5mm birch ply. Instead of using a spacer I milled away 1mm in the area of the flange. also I gave the edge a 45 degree facette to allow for irregularities (resin drops etc) in the fuselage.

You see the milled part below and the hard wood ply on top.
According to the plan everything is glued together and kept in position by the use of some weight inside the fuselage. As I don't trust my own skill in positioning this in the right way I had the idea to use screws. They will stay in the firewall as they wil be in contact with the epoxy resin. The screws allow to make a dry fit test to see if there are any places that need shaping to allow a snug fit.

See above the test fit of the firewall.
Now comes the messy part - to glue the stuff in position.

Edited By Vecchio Austriaco on 25/12/2011 19:23:51

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Found another item which would be easier to put in now - the structure to hold the tank.
Structure - which structure? first I need to build one.
Was not too difficult, it is just a light ply board which holds the tank down by rubber bands.
This board I glued in at lunchtime and after some phoenix stick throwing I glued in also the firewall. Again 12h epoxy - means no further work today.

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Here we are with the next update.
Next for the fuselage is the servo board - I am not sure now which servos will go there - but in any case the throttle and joke servo and the rudder servo. the two elevator servos I would prefer to install close to the elevator, but this depends on the COG which I can only see after the engine finds its place.
Problem with the servo board is the tank - if I want to have access to the tank in the future (and may be also to the ignition battery - depends again on the COG) the servo board needs to be removable. so I decided to make 2 consoles where the servo board will be fixed to by screws.
 

I use my usual araldite glue with some glass rovings - 12h waiting time....
 
To do something in the meantime I decide to go on with the wings. So I give them a final inspection and smoothen some irregularities with light filler.
I noticed also some early hangar rush which I corrected.
Used birch ply for correction on both end ribs.
and some hard balsa at the aileron
Now the covering can start.
I start with the tricky bits
It is straight forward - only the size wants some time...

Finally I put the things together - this plane is a dining room filler...




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great build, like the maching, well thought out and designed, i could not do better, just a question, the wings are plug on, although the outline of the wing matches the root shape on the fuzz, are you using an incidence meter to make sure the wings are truly in line? might also at this stage, be worth getting a pitts wrap around silencer, and cut a step in the bulkhead bottom to take it, this will negate cutting the cowl ??
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Incidence meter: as this is what they called in the 80th a quick build kit I follow the instructions. All positions as for wingtubes are marked on the fuselage and I hope they are true...
I changed the stabilizer to a profile design - but this is a symmetric design so it shouldn't change anything (I hope...)
In the picture you see the stabilizer slightly bent to the left - at this stage the part with the rudder hinges was not glued in place. I did it after taking the picture - now it should be o.k.
 
Engine and exhaust - now I will start looking for the right position. It will look out of the cowl anyway as the kit was asking for 35glow and I have a nice 45 petrol which I plan to use. So far I have not found any matching exhausts for this size and brand. I have a standard exhaust which is made for inverted engine position - but I am sure this piece of Chinese workmanship will not silence a lot...
 
Family is coming back today so the build speed will decrease a little...
VA
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Tried to find the right position for the engine - and after fiddling around with my positioning tool I saw that the best would be 90 deg inverted. For the exhaust I found a nice silencer in the internet - has only one disadvantage - which is the price... 70 €...
So these things have to wait until I order and receive the silencer...
Looking at the wheels I purchased some 2 years ago - I saw that the flange centre is quite wide. I couldn't resist - I looked into my spare parts box and found 4 matching ball-bearings. Out with the prop reamer and on we go.

But I had to pay for my cheeky light run wheels...
The prop reamer is fine for the job it is thought for - doing more gives you a nice blister....
VA



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Having made this gadget I have to find also an axle. As the inner diameter of the bearings is only 3mm it had to be something hard.
Found several pieces of siver steel in my material box (115CrV3) which is normally used for tool production. Exactly what I need. But: Blooming hard. It took me quite some time to produce the axles. Especially the thread was a beast - A normal thread cutter die doesn't work - so I had to cut it using the lathe...

In the end they are done and another piece is put into the puzzle.

Edited By Vecchio Austriaco on 02/01/2012 18:01:17

Edited By Vecchio Austriaco on 02/01/2012 18:01:39
slight spelling problems - and this is before the beer...

Edited By Vecchio Austriaco on 02/01/2012 18:02:34

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