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Old Mar 14, 2013, 01:44 AM
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2 metre speedwing.

Started this 'wing tonight, it will be a 1 piece 2 metre bagged carbon surface with carbon capped spars.

The cores were CNC wire cut by my building and flying buddy Dale and they came out great. The 'wing uses a modded MH-64 at 26 degrees sweep, -1 degree anhedral and transitional washout of 1.5 degrees. Power will be a HET Typhoon but not sure which yet.

I'm going to build a plywood bagging bench using the plan form of the 'wing including anhedral...lots to do.

I'll post photo's as I go if anyone is interested.


Tony

PS, the name of my 'wing 'Sebess' is a shortened form of 'velocity' in Hungarian and when anglicized is pronounced Shebess.
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Old Mar 14, 2013, 03:08 AM
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Interesting!Is the airfoil constant along the span?

Quote:
I'll post photo's as I go if anyone is interested.
Sure

Andrés
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Old Mar 14, 2013, 03:23 AM
I don't like your altitude
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More I hate the stuff
Winglets at the tips?
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Old Mar 14, 2013, 10:40 AM
less is more
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That is a tiny amount of wing twist.....This thing IS going to be fast. With that speed and wing sweep, you can't have too much carbon. One piece wing solves a lot of problems.

A "plywood bagging bench"? I can't imagine what that would be.


Looks like a cool project Tony. Keep us posted.

Kent
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Old Mar 14, 2013, 06:01 PM
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Started laying out the tow for the main spar caps, it starts at 4mm in the centre and transitions to 2.5 at the tip...I'm using a derivative of the spar set up in this article from B2 Streamlines:

http://www.rcsoaringdigest.com/OTW/o...uppression.pdf

To achieve the rounding of the spar caps I'll route a channel in the back side of the bagging bench and bag the caps up in there with a squishy plastic plug on top so they will also have the anhedral.

Andrés, the tip section is the MH-64 thickened slightly and lightly blunted at the leading edge...I've had luck with this set up in the past so IMO no sense in changing what works.

Stu, yup tip mounted winglets which will have their main mounting location tied into the end of the spar but most of their mass behind the spar. Did a little modeling on this and it 'might' work out okay.

Kent, I'm hoping for 200+ KPH but who knows? I'll post photo's of the bench set up, it's really simple and makes for an easy/accurate lay up and bagging.


T.D.
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Old Mar 14, 2013, 07:06 PM
I don't like your altitude
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http://www.rcgroups.com/forums/showt...colibri&page=2
This may be of interest.Tow both sides of the hinge line.
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Old Mar 14, 2013, 08:01 PM
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Thanks Stu, I've read that thread a few times. The spar on my 'wing will be 5 or so mm in front of the hinge line with the A-frame set up as shown in the article I linked to...but I am going to add a lighter spar at a point behind the leading edge as I want this 'wing to be as ballistic as possible.

I'd like to say I'm hunkered down over my plan right now but the truth is I'm washing tonight's dinner dishes.


Tony
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Old Mar 16, 2013, 02:48 AM
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Started the spar slots, 9mm wide with a crescent transition at the root for a constant width and tapered thickness carbon cap top and bottom with a +/- 25 degree, 3mm thick carbon cloth shear web between them. I could get away with no shear web at all but the bit of margin the web supplies is worth it IMO.

Thinking of going with 30% tip to 25% root elevons only (no flaps) on the outer 50% of the semi-span...opinions are most welcome on this idea.


T.D.
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Old Mar 16, 2013, 10:25 AM
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I'm not quite clear on how you plan on adding shear to your spar. A few more piccies, when the time comes, would be helpful. I like the idea of crossing the spars and connecting them....see attached.

This looks similar the the CO5. IIRC, they used elevons that were 1/3rd the halfspan plus a similar elevator at the root. It would certainly fly with just elevons.

Looking forward to how you plan on attaching the winglets. Many different approaches there.

Kent
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Old Mar 17, 2013, 12:45 AM
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Kent, to achieve the shear webbing I will lay in one side of the tow spar (the top side first) then hot wire a vertical slot in the centre of the bottom spar slot that goes through the core span wise and ends at the pre bagged top tow spar then insert the pre-cured 25 degree bias carbon cloth shear web ...it makes for more work and fiddling but what the hay.

I'll post photo's when I do it...maybe a video if I can set that up.

Tonight I finished sanding the spar slots...what Vernon Hunt calls "ditches". Instead of a forward carbon tow spar I'll lay a full span 5cm root to 3cm tip wide piece of uni against the core in that area when I lay up the 'wing.


Tony
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Old Mar 17, 2013, 04:16 AM
I don't like your altitude
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Just wondering if you might be better with a line of tow either side of the hinge?It would add a lot of stiffness to the surfaces
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Old Mar 17, 2013, 02:36 PM
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Good idea Stewart.

I'm going to put a 1K disser on the elevons so tying that into the span wise tow you suggest will be good.

We are finally having some sunshine here so I'm off now to do some 1/12 electric combat.


Tony
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Old Mar 20, 2013, 03:22 AM
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Laid the carbon tow spar caps in tonight, I'll post a photo tomorrow after they come out of the hot box.

Here is a look at the slope version of the finished product, FLZ doesn't really lend itself well to plan form photos' so I laid it out in XFLR5...I like it.


T.D.
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Old Mar 20, 2013, 05:29 AM
I don't like your altitude
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Nice!
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Old Mar 20, 2013, 03:03 PM
the answer 42 is
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Careful with XFLR5, it is sometimes very optimistic of how far you can bring your CoG. In my experience it happens more often with Fw than with regular planes

EZ
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