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Old Mar 13, 2015, 11:25 AM
making my own planes...
decones's Avatar
Curitiba - Brazil
Joined Oct 2007
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Quote:
Originally Posted by ALEX HEWSON View Post
Really cool scratcho developments all around the world
Yes! I Had To threaten Marcio, I sad my house would born earlier than his Scratcho...... It worked!!!
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Old Mar 13, 2015, 06:55 PM
AvB
Wind, hill, ... I'm keen ...
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Australia, QLD, Woody Point
Joined Nov 2006
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I agree Marcio, I think you will have enough work just to get the first SCratcho made! Good luck with the preparations and have a great trip!
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Old Mar 14, 2015, 01:28 PM
no pain, no pain
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Brazil, PR, Curitiba
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well.. half the work is done... lots of fun for the weekend LOL
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Old Mar 14, 2015, 07:41 PM
AvB
Wind, hill, ... I'm keen ...
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Australia, QLD, Woody Point
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Hey Marcio it looks excellent! Do you have only the 2 alignment locations? I only have 2 alignment pins in my Scratcho mould but I wished I had put more in, particularly in the centre area as the moulds have become just slightly misaligned in the middle.
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Old Mar 14, 2015, 08:55 PM
no pain, no pain
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Brazil, PR, Curitiba
Joined Dec 2006
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hi Andrew, I have more 2 places where I will drill at the end of the work before oppening. I placed two pieces of hard wood at these places. they are in oposite positions of the alignment bumps you saw at the picture. but they are at the corners also...
after read your comment, with the help from Christian , we drilled more two 1/2" alignment points at the center. need to seal and wax them well now. problem solved
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Old Mar 14, 2015, 08:56 PM
no pain, no pain
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Old Mar 15, 2015, 02:00 AM
AvB
Wind, hill, ... I'm keen ...
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I got stuck in to finish the hardware and close the moulds of the latest wing. The spar is CNC cut, the dragspars are CNC cut with carbon facings front and back, and the aileron stiffeners were made by very carefully hot wire cutting some foam to the correct thickness and taper, then slicing it up in square section from the tapered sheet, then the carbon sock slipped over. As you can see, they're quite thin.

This afternoon I finished the preparations and even placed the servo wiring in routed slots. I wet up the socked spar stiffeners with LC3600 and put them in place. Then used the Compset 121 epoxy gel to smear over the blue foam faces, and also with a fine tip I syringed it into the slots cut for the dragspar and the main spar - and also around the edges near the tips and along the trailing edge.

A bit of thick splooge for the wing bolt areas and then I mixed up the Sicomin PB250 foaming epoxy. I had measured the volume of the D-Box area (a bit under 800mL) so since it expands to 4 times, I put 200mL into the D-box. I left it lightly clamped for about 15 minutes, to let the foaming epoxy push the air out through the leading edge, then clamped it all up.

I'll give it a day or so to harden up, then I'll give it a post-cure process and let's hope that it doesn't sink back! I hope not ... I really think this might turn out to be the best SCratcho wing ever, for stiffness, durability and moderate weight.
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Old Mar 15, 2015, 04:05 AM
377 beeatch!
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Australia, QLD, Toowoomba
Joined Jan 2010
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That's super impressive Andrew! you've blended so many cool techniques into the one wing!
I bet it will turn out great.
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Old Mar 15, 2015, 05:07 AM
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Brazil, PR, Curitiba
Joined Feb 2005
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Andrew, you are taking the scratcho to a high quality level. So impressive the techniques and the precise working you have been doing. It is definitely a craftsman work. I can't wait to see our Brazilian's Scratcho version cutting the air soon.
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Old Mar 15, 2015, 06:36 AM
The seasons are changing
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gold coast australia
Joined Aug 2008
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Brilliant work Andrew , well done
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Old Mar 15, 2015, 08:24 AM
Where is the inspiration
wdeighton's Avatar
Moira
Joined Feb 2006
870 Posts
Oooo to have my own cnc machine to be able to do that.

Now you have take the plunge with the loom, next time the servos?

Only concern is the expanding epoxy.

I was thinking a noodle of foam in the D-Box area may help the sink back by reducing the maximum thickness of expanded epoxy?

Good work.

I do agree, the inner quality of these scrachos are second to none!
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Old Mar 20, 2015, 10:32 PM
no pain, no pain
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The brazillian scratcho fuse mould READY !!!!!!
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Old Mar 27, 2015, 11:14 AM
no pain, no pain
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Now is time to assemble it. I have a little more than 20h available to do this.
Funny is the fact that the friend of mine that I asked to paint it, made a mistake and painted the wing and stab upside down !!!! Lol.... Willl put some adhesive vinil to correct it.
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Old Today, 07:48 AM
no pain, no pain
marcioh's Avatar
Brazil, PR, Curitiba
Joined Dec 2006
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unfortunately I am very sad . I was unable to finish it before my trip to USA , where I would spend some nice days flying it. A lot of things happened before the trip including a big leak in my house water heater 2 days before the trip. but the biggest problem is my total failure in time managment. not only my hobby related projects are late, almost all the things in my life. now I will spend the nice 22 trip days with my family and when I return home will try to start life new. will bring 2 48" planks to at least have the weldon feeling again.
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