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Old Jan 05, 2011, 12:54 PM
G_T
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Kristof,

I am curious about your CNC machine. What make is it? I have been studying up on CAD programs some and have started looking into machines.

R&G,

I need to place an order with you guys soon... Hopefully your atypical European winter has calmed down! And thanks for the link!

Gerald
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Old Jan 05, 2011, 01:28 PM
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hi,

the speed is ok now , i get 8500mm/min
i use a 1.6mm ,2 flute cutter(no ball end) to cut the cores , main reason for that : i wan't a 1.6mm gap for the aileron's and i used a 1.4mm precured rod as for spar this time.(it fit's that slot nicely)

the bottom side is cut first indeed , for the second halve the rohacell fit's into a deeper cut negative so it's exactly positioned and the airfoil is perfectly cut.

i can just load the file anytime and start cutting...

-kristof-




Quote:
Originally Posted by Traian View Post
Khristof you can get it faster yet.
I noticed that you use a small 1/8 or 3mm end mill. May I suggest using the largest ball nose end mill you can fit inside the router. 3 flute ball nose work great. If you need help with programming I can help you if you use G Code in your machine. I use Master CAM and I can import IGES DXF STEP files etc.
Another idea here is for you when you cut the top of the foil. It looks that you are cutting the bottom first then you cut the top. The issue here is that the bottom of these wings is not flat and when you flip it over and place it on vacuum it changes the shape and the foil. You need a negative to place the wing in to before you cut the other side. If you make this negative pay close attention to the trailing edge and maybe add a removing feature to it with some pins for alignment so you can put it on the table and remove it when you do not need it and make a note for your offset position. Then next time you need to make another wing just place it in position recall the offset, load the program and go. A faster spindle will work too here with faster travel too.
I like your machine and just by looking at the ways it tells a lot about the quality of the machine. I was thinking of building one just like that with 48 in of travel by 24 by 6 in of travel but I have no money.
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Old Jan 05, 2011, 01:59 PM
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It souds that you need a tool changer. This will eat up your time.

Traian
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Old Jan 05, 2011, 02:01 PM
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why,? i do the whole wing core with that cutter.

( i get the cores done in 3 hour's now)

-kristof-
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Old Jan 06, 2011, 01:53 PM
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hi,

i pulled a second wing today and results are good!

i used 25gr glas for skin like i use on the tail's

torsionally it need's more stifness, bending is ok.

CF d-box should take care of it

weight 107 gr.

-kristof-
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Old Jan 06, 2011, 01:58 PM
I ♥ Carbon Fiber
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Wow! 107g, that's nice!
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Old Jan 06, 2011, 02:32 PM
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hi jonas,

sure that's nice but it needs something to stiffen it , D-box or disser (or both)

i think 120 gram should be possible .

with rds , it' ll be around 140 i supose.

-kristof-
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Old Jan 06, 2011, 09:37 PM
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Is there a reason why you did not tie the carbon patch on the top of the wing to the spar? A good engineering technique to eliminate stress risers is to taper the reinforcements rather than end the square. That creates high concentration of stress and if the wing fails I guarantee you that there is where it will break. Great weight although.
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Old Jan 07, 2011, 01:56 AM
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hi,

i mean to build it with a d-box(wich will take care of this problem)

i just wanted to see if the spar looked ok and the LE reinforcments too.

the patches were put in to use the wing if possible , torsional stifness is very low so i doubt i will put servo's in.

but i know this method works out now so i can build a d-box next time .

-kristof-
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Old Jan 10, 2011, 08:50 AM
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hi,

new fuselage mould's are cut , the fuse can take 2 big servo's now (side by side)

and the canopy has a straight hinge line now so the canopy itself can be taped(hinge) and on the other side held by a magnet.

also the vertical can be mounted like on the drawings in post 1

now the fun part can begin , wet sanding and polishing!

last picture is the new wing on an old fuse.

-kristof-
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Old Jan 17, 2011, 01:28 PM
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first fuselage!

hi,

the first fuselage of this new mould is curing for the moment , evrything wen't well(experrience has something to do with it i guess)

i expect it to come around 40 gram , i could get a few gram's of probably but this one will be very stiff)

my new zone v2 mould's are polished and ready for usage.
i'm cutting a negative vacuum plate for the moment so cutting rohacell cores will be something for tomorrow and hopefully the day after laying up a new zone wing.

-kristof-
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Old Jan 17, 2011, 01:36 PM
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pictures of the new zone v2 mould's
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Old Jan 18, 2011, 12:18 PM
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improved rds

hi ,

i've been working on my rds system and made an important improvement.
i made a alu transition part between coupler and cf tube, this way i can tighten the set srew witouth crushing the cf tube.

i got it at 4 gram's / servo now (coupler, wiper , pocket).

here are some pictures .

the carbon tube and the alu transition piece are gonna get wrapped with a carbon sock to add torsional stiffnes.

-kristof-
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Old Jan 18, 2011, 12:49 PM
G_T
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Carbon and aluminum combination is tricky. You need to paint one or the other of them with a non-conductive primer of some sort before bonding them together. You want no possibility of direct contact. Othwise, you experience galvanic corrosion and the joint will fail. It is only a matter of time.

You can further reduce weight if you wish, by tapering the aluminum where it goes over the carbon.

Gerald
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Old Jan 18, 2011, 01:02 PM
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gerald,

just came up with a solution for that AND it reduces the weight too.

i will grind 2 flat sides on the alu piece on the side were the carbon tube goes in and also make it thinner in the middle .

so the carbon sock will hold evrything together also...

-kristof-
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