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Old Dec 28, 2010, 10:01 PM
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Thomas Wang's Avatar
Beijing
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Quote:
Originally Posted by krikkens View Post
hi,

rohacell cores are almost done.

aileron, spar and wingmount holes are cut into the cores , the first one i'm gonna make is without rds , that will be machined too on future cores.
mould is waxed and painted .

i'm gonna use carbon tow for sparcap wich hopefully fit the cnc'ed slots well.
if the wing has no sufficient bending stiffnes i'll cut a thin slot all the way thru and glue a thin piece of hardwood in , this should do the job, no doubt.

here are some pictures , more to come...
This is great, what concern me is if the rohacell core weights too much?

Thomas
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Old Dec 29, 2010, 12:51 AM
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South Africa, GP, Centurion
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Hi Kristof,
Is the rudder going to be a pull-spring setup or normal pushrod system?

Regards
Rudolf
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Old Dec 29, 2010, 02:17 AM
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hi,

weight of the cores = 40.1 gram (for both halves)

rudder is ment to be pull-spring, this is what i've been doing last year witouth problem's so...

but it would be very easy to install a rod/tube also...

-kristof-
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Old Dec 29, 2010, 02:26 AM
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I just read through the old thread.
Well done.
I'm at the point where you started.
Busy making a plug for fuselage.

Rudolf
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Old Dec 29, 2010, 05:23 PM
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hi,

i pulled the first wing today!

i was a little to impatient and opened the mould after 20 h , result : delamination

it had to do with the pva i used too, normally i spray it on ,(a relatively thick coat ), now i used a pva sponge to do the job , but the layer of pva was way very thin .
the upper side of the wing is much better then the bottom side ,(had troubles with the pva on that side ,probably not properly degreased or something...)

at least now i know the exact weight of the part's:
rohacell cores: 40.2 gr
CF for spar and LE reinforcement: 55gr
glas skin : 43 gr
rest : 10 gr

it should be 20-30 lighter , the spar is waaaay to much

-kristof-
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Old Dec 29, 2010, 05:29 PM
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Hong Kong
Joined Sep 2010
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Kristof,

I love that color scheme, good job!
What airfoil is that?
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Old Dec 29, 2010, 05:44 PM
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Quote:
Originally Posted by ThomasLee View Post
Kristof,

I love that color scheme, good job!
What airfoil is that?
hi,

edge series by GT

-kristof-
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Old Jan 04, 2011, 03:00 PM
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hi,

new mould's for vertical and horizontal are done .

vertical has the edge vertical airfoil and a 2.1dmē area

horizontal has the ht 22 airfoil and also 2.1 dmē area.

vertical is bigger than the one i used last year , this should get the plane quicker into a straight climb (can't wait to find out on the field)

horizontal is slighly smaller than what i used to fly to compensate weight of the vertical and it should be better balanced according to wing area too.

hope to pull the first part's next week...

-kristof-
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Old Jan 04, 2011, 03:02 PM
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Why do you use the HT22 on the horizontal instead of the Edge foil?
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Old Jan 04, 2011, 03:08 PM
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hi,

edge is ment for full flying...

-kristof-
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Old Jan 04, 2011, 03:09 PM
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i forgot the pictures....
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Old Jan 04, 2011, 03:12 PM
I ♥ Carbon Fiber
Jonas M.'s Avatar
Germany
Joined Apr 2006
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Nice molds!

Hinged Edge stab airfoil can be found here:

http://www.rcgroups.com/forums/showthread.php?t=1238997
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Old Jan 04, 2011, 03:47 PM
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jonas,

yeah , i know that one , the fixed hinge location bothered me . i like a big moving surface but that one leaves very little for mounting it on the boom .

-kristof-
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Old Jan 05, 2011, 08:49 AM
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United States, GA, Roswell
Joined Mar 2008
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CNC Advice

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, 12:28 PM
R&G
Composite Technology
Stuttgart
Joined Oct 2005
79 Posts
Quote:
Originally Posted by krikkens View Post
at least now i know the exact weight of the part's:
rohacell cores: 40.2 gr
CF for spar and LE reinforcement: 55gr
glas skin : 43 gr
rest : 10 gr

With precured UD material you should be in the range of + 5-10 g for the spar. The required groove could be milled in the core. Try our range of carbon rectangle high modulus profiles and carbon rectangle profiles
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Last edited by R&G; Jun 20, 2011 at 03:28 AM. Reason: Wrong link
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