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Dec 27, 2015, 01:58 PM
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Hussle's Avatar
Quote:
Originally Posted by Knoll53
Here's my theory. Adding camber to a wing will create good lift at a slower speed, thus allowing tighter thermal turns..............it's a good thing.

With full span elevons and flaps the entire wing can be cambered. Here's how. Make the flap as long as possible while maintaining a pitch positive effect. The remainder of the wing is elevon. Compensate for the pitch positive flap with elevon deflection, which would be a downward deflection, thus providing a fully cambered wing.

Kent
Sounds brilliant Kent, thanks for the advice

Hussle
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Dec 28, 2015, 04:31 AM
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Hussle's Avatar
Ditches for carbon tow all marked up on both wings, and sanded on one wing.

Tomorrow's work will be to sand the rest and lay up the tow on one side of the wings.

Spars are forward and rear (top and bottom), diagonal connecting spar (top and bottom) and a spar through the control surfaces (top only).

Hussle
Dec 28, 2015, 09:34 AM
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Looking good.

So I see that you have moved your sub spar back to the elevons AND put in a diagonal spar. You've certainly done what you can to maximize strength for this construction method.

Did you check the layout of the joiners with this new layout? I can imagine that the main joiner, the aft one, will be a very tight fit in the airfoil.
Dec 28, 2015, 03:13 PM
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Hussle's Avatar
Quote:
Originally Posted by Knoll53
Looking good.

So I see that you have moved your sub spar back to the elevons AND put in a diagonal spar. You've certainly done what you can to maximize strength for this construction method.

Did you check the layout of the joiners with this new layout? I can imagine that the main joiner, the aft one, will be a very tight fit in the airfoil.
I did check, the aft joiner has always been as far back as fits in the airfoil for maximum length and is quite a tight fit, but does not interfere with the other spars

Hussle
Dec 28, 2015, 07:34 PM
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I got to say, it sure doesn't look like the joiner assembly will fit......

If you say that it fits..............then it fits.

Dec 29, 2015, 12:35 AM
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Okay, unfortunately I left it a little late in the day to start epoxying, so progress for today was sanding out the rest of the grooves, cutting the slots for the boxes and wrapping the boxes in tow (yet to be epoxied).

Tomorrow's work should be to glue the joiner boxes into place at the correct angles.

Hussle
Dec 29, 2015, 11:23 AM
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You are making good progress. This model building game is a lot more fun when you build a little everyday. Once a project gets "cold" some times you never come back.

Please don't change a thing based on my comments. I'm just opening up a discussion right in the middle of your build log.

Wrapped joiner boxes ! Like it. If you could figure a way to wrap the spar at the joiner box connections you'd really be maximizing strength.

I think you might have a slight anti-rotation problem with the current joiners. If you do, it is easily fixed with the addition of a small alignment pin at the aft spar.

Kent
Dec 29, 2015, 04:01 PM
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Yeah, trying to get the maximum length out of the main joiner didn't leave enough space for a rear joiner, so it's just going to have a small alignment pin at the back.

Hussle
Dec 29, 2015, 07:22 PM
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Quote:
Originally Posted by Hussle
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
Wow, thats nothing. I have upwards of 280 grams. I will certainly try next time with less weight.
Last edited by Knoll53; Dec 29, 2015 at 08:00 PM.
Dec 29, 2015, 07:46 PM
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Bent Spars


A good way to connect the carbon spar caps and the joiner box is to lay the tow right over the boxes. this way you eliminate the front joiner and put the battery there. Based on what you have, this is what I would do.


comments from the local suspects?
Dec 29, 2015, 08:16 PM
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Quote:
Originally Posted by Knoll53
A good way to connect the carbon spar caps and the joiner box is to lay the tow right over the boxes. this way you eliminate the front joiner and put the battery there. Based on what you have, this is what I would do.


comments from the local suspects?
Here's a practical example on my latest project pretty much just as Kent has illustrated.

Rectangular aluminium joiner bar for built in anti-rotation.
Last edited by guitarcher; Dec 29, 2015 at 08:18 PM. Reason: Added a bit.
Dec 29, 2015, 11:13 PM
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Nice guitarcher..........is there a build log for this beast?
Dec 29, 2015, 11:56 PM
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Hussle's Avatar
Quote:
Originally Posted by Knoll53
Wow, thats nothing. I have upwards of 280 grams. I will certainly try next time with less weight.
The weight was this low only because my bow wasn't strong enough to put a lot of tension on the wire, the low weight gave a nice smooth drag and prevented rippling.
Stick with what works for you.

Quote:
Originally Posted by Knoll53
A good way to connect the carbon spar caps and the joiner box is to lay the tow right over the boxes. this way you eliminate the front joiner and put the battery there.
I'm afraid that I've already glued the joiner boxes in place, but I will certainly be running tow over the boxes to join the main spar. I was planning to put all the electronics in the pod anyway.

Speaking of electronics, I was planning on using these servos. Thoughts?
http://www.hobbyking.com/hobbyking/s...sec_18_8g.html

Hussle
Dec 30, 2015, 08:49 AM
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Quote:
Originally Posted by Hussle
I've already glued the joiner boxes in place,
Hussle
That's what I like to hear. A modeler that BUILDS!

Your approach with joiners and pod sound good. Of course the pod can help protect the flaps from a ground strike when landing.
Dec 30, 2015, 09:17 AM
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BTW, just for reference, THIS WING, has just one bent spar and a rectangular joiner and I flew it for months without an alignment pin. The whole wing hung off of the joiner.


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