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Danny's "poor mans Spitty"


Danny Fenton
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Posted by Charles Galloway on 13/10/2014 11:28:50:

Have you any tips for cutting the tapers on the ends of B3 so as to get a nice flat surface?

Maybe the laser cut parts come ready tapered.

Charles, the laser cut B3 parts are not tapered.

To make producing the taper easier without the use of machinery (Sorry Danny), I shortened one B3 piece before joining. If you look at the drawing you will see that the taper is only on the outer 4 ". So, Mark a centre line on both B3's and remove 1 7/8" from each end of one B3. Glue the 2 B3's and clamp well. Make sure they are flat in the middle and wipe off any excess glue. When dry, you will have a much easier hand sanding task.

I hate sanding plywood. angry

Eamonn.

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That's not a nice sanding task there good luck Charles, I am sure you will get there

When assembling the wing watch out for Rib 2 leading edge I am not convinced it is the right shape at the front. When I lay a straight edge along the top that one stands proud. Might be my shoddy building embarrassed

Cheers

Danny

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Posted by Danny Fenton on 13/10/2014 14:09:28:

That's not a nice sanding task there good luck Charles, I am sure you will get there

When assembling the wing watch out for Rib 2 leading edge I am not convinced it is the right shape at the front. When I lay a straight edge along the top that one stands proud. Might be my shoddy building embarrassed

Cheers

Danny

Are the ply pieces in the wood pack made from birch ply or liteply?

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Well I am not sure, its as hard as Birch ply but a darker color. Its much harder than lite ply and there are 5 layers to each piece so ten in 1/4 inch laminate. Yes I would suggest you use Birch ply.

My wife is away so got a fair bit done.

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Firstly the trailing edge was completed.

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Then the leading edge added, while drying the shroud was added. I made the shroud slightly differently on this wing. Instead of running the shroud to the back of the capping strips. I stopped it 1/8 short. The shroud grain runs fore and aft because it is overhanging the wing and needs the strength in that direction. However where it meets the cap strips was ugly, so I have added a spanwise strip of 1/8 x 1/16 just to give an nice edge wink 2 does nothing but make it neater.

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If you have OCD this pic should scream out at you wink 2

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Then I moved on to the bellcrank installation. Firstly I needed to plan a path for the piano wire. This is always a bit of a guess because until everything else is in place you don't know if you guessed correctly.

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I used Thunderbird "Permagrit" to tunnel its way from the root to the tip

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I ran a piece of 1/8 sq through to check that I was hitting the underside of the bellcrank, the output to the surface will be from above and cross over the other.

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Ditto, but further away

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More bellcrank stuff

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This is the underside of the belcrank plates, simply made from 1/16 ply and re-inforced with some 3/16 stock. The nuts are tight and glued.

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Cheers

Danny

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The finished wing panel (top at least) was then removed from the board and after struggling for twenty minutes managed to slide the sections together. I tell you there must be a better way. If anything had been a "gnats nadger" out it would not have fitted. But fitted it has, and we have a very long and skinny wing!

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Furthermore the incidence appears to be equal from one side to the other. The dihedral however is not equal. 51mm on port 61 on starboard crying 2 I will take a look tomorrow to see if it can be altered, at this point I am tempted to just sand the centre section to make it equal and be done with it....

I would suggest perhaps the best way to do this is not the way I have and to perhaps build the second wing straight onto the first wing, including centre section.

We need to see what the next builder comes up with, is that you Terry, Charles or Martin? I got lucky because they do fit, but if you are out by a fraction they would not interlock.

The fit on mine is so tight I probably don't need glue! At one point I was tapping the spars at the wing tips driving them home crook

Cheers

Danny

Edited By Danny Fenton on 13/10/2014 23:56:11

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That's a job well done Danny! Thanks for all of that I'm sure we will either be following your technique to some extent or other. Not the easiest of wing builds eh?

I have to confess that I succumbed to another bout of flying at my 'new' club yesterday - well it was a lovely day! blush As I've hardly flown in the last 3 months maybe I can be excused?

I have declared to SWMBO that today will largely be a building day! That will be finishing off the tail pieces including sheeting the fin and adding ply to the shrouds. Then we'll see if there's anytime to think about the mainplane

Terry

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Thanks Terry, I will value your thoughts when you can cast your eyes on the wing plan, as I am sure I have made a meal of the procedure for the wing, I could say "I Have managed" but that's not fair on the other less experienced guys. This is not an easy plan to follow and understand the designers thought process. Did he have a thought process crook

I have made the second wing panels shroud an 1/8th wider so we can shave an 1/8th off in front of the flaps perhaps. Have to rip the other side off if it works and redo. Was not terribly happy with the angle. A word of note here the shrouds have to follow the line of the ribs, which means sanding that shroud gusset. Not easy to do acurately and mine was a little too flat.

Hi Nigel and thanks yes might be an idea to see how one of the other experienced builders tackle it, as i don't think I have set a good example.

Cheers

Danny

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That’s a great wing build well done and thanks for the insight. I think I would have taken longer thinking about the job than you have to build it and probably still will.

If I have to build the second wing panel onto the first (and it does seem like a good idea) then I will need to commandeer the dining room table. This poses the question, do I start now and try and complete before Christmas or postpone the wing until the new year ?

Yes my builds do take that long, I’m still on with the tail. The good thing is although it is complicated it all looks doable. I’m a one piece at a time man and I try and work it out as I go along but you get there. Having seen your wing so far I’m quite confident. Although a bit worried about Christmas lunch !

Nice Job, Nev.

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Go for it, shouldn't take long wink 2

I would leave the triangle stock and shroud off the trailing edge, you might then consider flipping it, once lifted from the board, and adding feet to the leading and trailing edges so you can sheet the underside and keep it straight.

You can eat Christmas dinner on a tray in front of telly Don't tell your SWMBO where I live smile o

Cheers

Danny

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Oh by the way overnight the wing healed itself and I have 60mm under each tip (Rib 18) so I am not sure what's happened there. Those dwarf carpenters maybe worked overtime.....

Anyway threw thin CA everywhere and its all locked in now. I am going to add some triangle stock, along the rib to spar joints, as the fit is not brilliant and there are a few small gaps.

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Centre sheeting over the leading edge is also in place. Need to think about even if you don't do it, the servo placement

Cheers

Danny

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Thanks Tony, but I fear its not worthy of such praise

Well I have trimmed the shrouds, what I have effectively done is made the aileron shroud deeper while leaving the flap shroud as intended. When it comes to the flap and aileron construction we will see if we can shave a little of the aileron leading edge. This will allow us to add some material to the wing trailing edge in front of the aileron and give the impression that the flap is deeper into the wing than the aileron. Fingers crossed as its a work in progress.

But first I fitted the flap bellcranks. Remember I am using a single central servo so the bellcranks have to be handed.

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They bellcranks are shown in the up position a

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You can see in this shot that the hole in the trailing edge has been simply mirrored, this is not as per the plan, nor my model. Because the bellcrank is one bay further outboard the hole needs relocating

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Here you see the step in the shrouds, only an 1/8th inch wider on the aileron shroud.

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We will have to see how it looks.

I am stalling becuase before I can sheet the wing underside I need to make up the undercarriage stubs, that means bending 8 SWG (4.06mm) piano wire, next to radio installation it is my least favorite job

Cheers

Danny

Edited By Danny Fenton on 14/10/2014 15:42:52

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