CO5 build - Page 2 - RC Groups
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Dec 23, 2015, 03:38 AM
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Hussle's Avatar
Okay, after much experimentation, it turns out that using a low heat works, albeit very, very slowly. I'm sure ice ages came and went...

So, I now have one core cut, and 3 more to go, wish me luck!

Thanks for all the help.

Hussle
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Dec 23, 2015, 03:50 AM
You know nothing....
Stuart A's Avatar
A good way to tension the wire with your setup- Spanish windlass
Dec 23, 2015, 04:13 AM
Registered User
Hussle's Avatar
Quote:
Originally Posted by Jon Snow
A good way to tension the wire with your setup- Spanish windlass
Of course! Should have thought of that. Thank you very much
Dec 23, 2015, 04:26 AM
Registered User
Hussle's Avatar
A few more details on the setup:

I found that a few dots of CA glue on the templates made sure that they stayed put perfectly.
Each cut took about 15 minutes (yes, I know, but it works)
I marked the top of the blanks with a scale so that it's easy to see whether one side is lagging behind, and I got better results by pulling the slow side rather than slowing the fast side.
The trailing edge required a light sand in order to remove a few small ripples.
The weight on the pulley is about 75 grams.

Hussle
Dec 23, 2015, 07:52 AM
Registered User
Hussle:
Another way to increase the tension may be to use a guitar machine (doohickey that tightens a guitar string). Someone posted a very simple setup that was a piece of plywood with a guitar machine. They're cheap, I ordered some on Amazon ... I think it was 6 machines for $10. Of course if you're smarter than me (most people are) you might be able to source one in a much cheaper way (scrap pile, garage sale, garbage, dollar store, etc.).

-Dave

Dec 23, 2015, 11:21 PM
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EdSoars's Avatar
Great idea! Those sre for nylon strings might not put enough tension on a steel wire. I can send you a steel string tuner if you want.
If you tell me how long your wire is, I'll also tell you what note to tune it to! This might be a major advance in foam cutting!!
Dec 24, 2015, 04:37 AM
Registered User
Hussle's Avatar
Success!

All cores cut (very slowly) and cut to shape for the sweep angle.
Next up is the joiner boxes and wing spars. How many spars would you recommend, with how many runs of tow in each? (I have 120m worth of 12k, should be enough I think )

Cutting time was improved to about 7-8 minutes per side with a slightly higher heat, and the Spanish windlass worked well thanks Jon.

Merry Christmas to all,
Hussle
Dec 24, 2015, 04:41 AM
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Hussle's Avatar
Quote:
Originally Posted by EdSoars
If you tell me how long your wire is, I'll also tell you what note to tune it to! This might be a major advance in foam cutting!!
Funnily enough my wire did hum a note. Must have been the switching frequency of my power supply or voltage control.
Dec 24, 2015, 06:10 AM
You know nothing....
Stuart A's Avatar
See what the other guys say,but Verns method worked well for me-
https://www.rcgroups.com/forums/show...1571140&page=2
#21-23.
Dec 24, 2015, 07:40 AM
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miniphase's Avatar
They look like good cores.....you did remember to cut them with the required washout didn't you?
Dec 24, 2015, 02:59 PM
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Hussle's Avatar
Quote:
Originally Posted by miniphase
They look like good cores.....you did remember to cut them with the required washout didn't you?
Yep, though I was initially going to cut the first one with washin, caught myself in time though.

Hussle
Dec 24, 2015, 07:36 PM
Registered User
Hussle

Yet another way to tension the cutting wire, threaded rod and wingnuts.-

Been following your C05 build with interest, looks like you have used the same foam as I have on my 1200mm span wing, still unfinished.

Merry Xmas
Stewart
Dec 24, 2015, 11:22 PM
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Hussle's Avatar
Quote:
Originally Posted by morgans
Been following your C05 build with interest, looks like you have used the same foam as I have on my 1200mm span wing, still unfinished.

Merry Xmas
Stewart
Thanks Stewart, I got this foam from Bunnings, they sell it as knauf insulation foam.
Dec 26, 2015, 03:51 AM
Registered User
Hussle's Avatar
Not much work done for the moment, just the first of the joiner boxes made for the 15mm main spar. The anti-rotation spar will be 10mm. How long should the rotation spar be?

Hussle
Dec 26, 2015, 04:49 AM
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Hussle's Avatar
Also, thinking about laying up the spars again, it seems that everyone sands a shallow trench and lays the carbon tow face down in the slot. Has anyone tried cutting a thin, deep slit and laying the tow in edge up. This seems like it would obviate the need for a shear web or for relying on the foam to act as the shear web.

You could even cut the slit and then lay carbon face down above your vertically oriented tow, forming a "T" shaped spar, which might even help with torsional loads.

Seems like this could significantly strengthen the wing, or is added strength in this direction unnecessary?

Hussle


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