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Dec 26, 2012, 12:34 PM
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Knoll53's Avatar

Wing begins

This will be a vacuum bagged one piece wing. Glass skins with a built up spar. To be honest, I've yet to vac. bag a wing without some sort of problem. So I'll post all the steps so we see what needs improvement.

Also, I typically write a procedure as I go along. So I'll post that too.

• plot paper wing templates with all layout. spars, servos, elevons. tape templates together to form full wing panel with long straight edge.
• lay mylar over paper template. tape down. cut out mylar and paper template with one cut. Repeat for other mylars. 4 total for this one piece wing.
• sand raised edge at mylar as needed.
• Use paper templates to mark foam with sharpie. cut foam with drop bow a little large at the joints.

Blocking foam - The Gravity Cut (3 min 2 sec)
Feb 02, 2013, 01:28 PM
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Kicking around some color schemes. I've already got the fin in red, so that leaves the wing. Currently I've got some Navy blue and Harvest gold paint on the shelf.
Last edited by Knoll53; Feb 02, 2013 at 01:31 PM. Reason: add bottom 2
Feb 02, 2013, 09:55 PM
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1967250s's Avatar
I very much like this design and would like to build one. Would it be possible to get a side view of the fuse and rudder?
Feb 03, 2013, 12:16 AM
B for Bruce
BMatthews's Avatar
The gold lower tips will certainly show up best in a steeper bank out at a good distance. The red will just blend in with the blue when farther out. Otherwise the light top and darker bottom is always a wise option for any glider that will be flown out at a longer distance at times.
Feb 03, 2013, 09:51 AM
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Thanks Bruce. The color scheme is all about visibility at distance and visibility is becoming a bit of a problem. I've used red before and although it is generally dark and contrasts with the sky, I've have found it hard to see. I'll try the gold tips on the bottom.

@ 1967250s, I'm happy to see anyone build one of my prototypes based on what I post, but I don't take requests. I've got enough to do.

Feb 10, 2013, 02:53 PM
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Cutting cores

I got some nice cores from the Foamular 150. Here's the current version of the gravity feed hot wire. The birch plywood edged templates worked well.
Drop Bar hot wire cutter (2 min 28 sec)

The cores are all sanded out now and thinking about a lay up schedule. I have mountains of a rather heavy dense glass cloth, so that will be the outer skin. Not sure of it's exact origin but just the skins cut to size weigh 500 gms. this will be a stout wing. Lots of little doublers and hinges in folders ready for lay up.

Just did a quick calc.......looks like I'm using 12 oz/yd. glass....Yikes, that should be enough.
Last edited by Knoll53; Feb 10, 2013 at 05:31 PM.
Feb 24, 2013, 01:11 PM
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mhodgson's Avatar
Knoll53, I have started drawing up a built up version, very slight changes to the planform to allow for even rib spacing.

The fuselage is also built up. The nose is sized so I could put a whirly thingy as there are not many slope near me.
Still tinkering with the dimensions and materials sizes.

Still much to do, like joiner size/type deciding on 2 or 3 piece wing etc.
I think I will finish in glass cloth all over but not sure yet.
Feb 24, 2013, 02:49 PM
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@M: If you plan on flying thermal with an electric launch then conventional thinking would dictate a lightly built ship, but I haven't been able to talk myself into a lightly built ship in years. Indeed, I'm beginning to re-build previous projects with new mods for a stiffer spar. I've given up on using wood spar caps. Too many variables. But that's me. I've got 4 lbs. of CF tow on the shelf and I'm hell-bent on using it.

From the looks of your design, looks like you'll come in lighter than my prototype, even with the motor.

Feel free to post your build log right here along side mine if you like. It might motivate me to ramp up my efforts.

Feb 25, 2013, 04:08 AM
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mhodgson's Avatar
Always preferred making built up wings, even like cutting ribs, added to which I can build as and when time allows. Something finite about starting a layup if you are unsure about being disturbed.
Did you use the section unmodified? might have to thicken it for my servos, not that I've chosen them yet.
I'm leaning to 3 piece wing as it will make a nice compact size for storage.

I'll get the drawings done soon but the build might take longer. Too cold outside and the workshop has minimal heating in winter. though a build log might persuade me to get on with it.

Martin H
Feb 25, 2013, 10:27 AM
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Yes I am using an unmodified PW51. I'll be using big Hitec standard servos too, so there may be a slight faired bump at the servos. I'll maintain the airfoil at the top surface and have the bump at the bottom.

If any plane deserves the super fine control of a digital servo, it's a plank. I'll first try the analog Hitecs, set up with as much mechanical advantage that I can get to assure fine control.

BTW, Peter Wick suggests bottom hinges at control surfaces.

Feb 25, 2013, 10:40 AM
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mhodgson's Avatar
I may follow the same route re servos, as I have lots of standard servos lying around
I remember reading about tailless, particularly planks working better with bottom hinging allround. I also recall that a bottom surface turbulator just in front of the hinge can improve control response if it is lacking.

I can see why you went 1 piece. The joiners are giving me a headache trying to integrate them carefully with the sweep, I'll get there...
Feb 25, 2013, 04:54 PM
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Originally Posted by mhodgson View Post
The joiners are giving me a headache trying to integrate them carefully with the sweep, I'll get there...
If a 2 piece wing would be packable enough for you, then a short joiner should develop the full strength of the spar. See sketch. Happily there is no dihedral, so just the sweep must be dealt with.

Feb 26, 2013, 12:44 PM
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mhodgson's Avatar
2 piece was the last option if all else failed.
However, looking through my joiner bits and pieces box I came across some flat steel strip that will fit just right between the spars at the joint. Forgot I even had it, and should do the job well, particularly if bound in.
Feb 26, 2013, 08:27 PM
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1967250s's Avatar
What about making a three piece wing with the joiners at the outer flap and aileron break? Less chance of it breaking and then you'd have a straight joiner? You'd also have a much more easily stowable wing.

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