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Sabre made in Belgium


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20191204_222208.jpgAfter closing the wing with the upper wing skins (all with green zap) and trimming the edges ,the next thing to do is placing the middle wing piece (triangular stock hard balsa).For this task i'm placing the wing on a flat board side per side to get the parts in line with the bottomside of the wing.

I marked the position of ribs no2 on the wing skin for a reinforcement between wing and triangular pieces.I cant help thinking these parts will brake -off in the event of a hard landing....After all this part holds the wing to the fuse !!!

20191204_221904.jpg

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WAUW, Dirk... you've joined and top sheeted the wing already, your wing servos are close to being sorted and your fuse is more than halfway... or even further in the meantime...

Somewhere I'm envious of course, but also a bit 'disappointed' as you're going sóó fast that there is nothing really for me to try to copy...

Keep up the great work, young man.

Cheers

Chris

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Posted by dirk tinck on 08/12/2019 16:45:48:

20191130_233830.jpgFirst made a servo mount ,allways keeping in mind the low weight -rule no1.20191130_233824.jpg

Thanks for these photos Dirk, very helpful as I am at exactly the same stage. I am also using exactly the same servo!

Question, how are you attaching the servo to the mount - presumably a screw into softwood? I was going to do the same then I thought that if so one would never be able to get the servo out without wrecking the wing? Or have I misunderstood?

I was going to line the top sheeting with a piece of ply to give it stability then glue the servo to the ply with laminating resin which will pop off if prised with a screwdriver as per a mouldie, This, however is ply and balsa rather than fibreglass, so it may wreck the wing anyway?

What say you?

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20191214_220251.jpg20191214_215319.jpgThe idea is to make the doors in epoxy.

To protect the fuse ,i'm covering it with plastic foil.Then a few layers of epoxy resin is applied together with cloth.I'm using 4 layers of 200gr.

To press the whole down i'm using another plastic foil and some balsa strips and pins and leave it to dry.

This should be my first speed brake !The surface won't be 100% but good enough after some sanding.

Good thing is that i can still see the outlines i drew on the fuse.When dry i can copy them on the epoxy part and cut it out.

Tha plan is to make a complete ''insert'' for the brakes ,meaning they must be fully oprational before mounting them in the fuse.20191214_213220.jpg

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Very very interesting Dirk. I too am doing the speed brakes but will use a fibreglass fuselage so should be easier. Am very interested how you are going to hinge and operate. Very useful to have a top designer ahead of me. Great blog by the way. Very intriguing, like a mystery novel!

Edited By Peter Garsden on 15/12/2019 00:20:07

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I agree with McG - drooping hinge would be a nightmare because it would touch the ground on landing and get ripped off.

I notice that you are using 4 sheets of 200gm fibreglass. All I use for the fuselage will be 2 layers of 150gm then a layer of 80 gram followed by some splurge of resin and microballoons to finish. Since you are the master of fibreglass I am sure you are right but I worry about weight particularly in the rear of the fuselage.

Also, presumably you are going to make holes in the flap servo support pieces afterwards when you make the hole for the servo arm - I would use a small needle file, I think? I was thinking one had to make holes before putting on the top sheeting, but perhaps it is not necessary?

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  • 2 weeks later...

Hi Peter ,you're right about the thickness of the panels. layers of 200gr. will be enough,even 2 layers i guess...

As for making the holes in the servo supports :You can do this anytime with a needle file !

Back to the airbrakes : When you look closely to the real sabre you see the panels ''drop'' when they open. IMO the upper hinge must be situated deeper in the fuselage than the lower to get this result so i tested it15349169153_18d69a7e20_b.jpg

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As this is only a test i ''guessed the shape of the hinge parts. I made them out of epoxy plate, a bit to big just in case...They were gleued in place with Z poxy . Then sanded them with a dremel tool as much as possible to save weight ....yes allways ! The hinge pin holes were pré drilled again guessing their position. Looking at it after, they were spot-on !20191218_220418.jpg

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