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Old Feb 03, 2009, 12:47 PM
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i'm at that stage of "finishing" sanding on the LE, and i do have to say... it would be very nice to have on hand... i don't remember if there was any room on the plywood sheet for it or not. but it's still coming along pretty well, just using the ply root ribs for a good reference across the wing.

here is the latest pic of the wing... just got to get the spoiler servos in there, route the wires, and put the last sheet on the center panel to cover it up... then a touch more sanding, and it's about done... starting on the fuse and tails.
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Old Feb 03, 2009, 03:28 PM
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Looking good Matt! I'm getting close to your stage. I'm about ready to put the top sheeting on everything. I'm going with the traditional pull strings for spoilers so that will make things a bit simpler in the wing.

RE: templates: I had just planned to print out some S3014 templates of various chords and cut them out of mylar. Should work fine for sanding.

I ran the Yardbird numbers and found that the EDA is a touch lower than I might like for my flying style. As a result I have two sets of joiners. One set with the stock 8deg bend and another set bent to 12deg. It should be an interesting experiment to see how it affects handling.

Andy
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Old Feb 03, 2009, 06:31 PM
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Matt,

That sure looks familiar...... I guess that means you're on the right track.

Andy,

What did you run the numbers on? If you increase the dihedral angle, it will turn more crisply and thermal a little more easily, but on landings, it will be much less tolerant of crosswinds and little gusts. I have used up to 10 degrees and... as said... for my flying style, I didn't like it as much... But as I've always said, it's your toy, enjoy it your way. It's all good.

I'll be flying mine in the Woody event at SWC. I'll let you know how it goes. An aside, I flew it recently off a strong winch. The wings do bow a bit, but don't break... and the zooms are pretty nice......

Jack
Old Feb 03, 2009, 08:34 PM
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Quote:
Originally Posted by schrederman
Andy,

What did you run the numbers on? If you increase the dihedral angle, it will turn more crisply and thermal a little more easily, but on landings, it will be much less tolerant of crosswinds and little gusts. I have used up to 10 degrees and... as said... for my flying style, I didn't like it as much... But as I've always said, it's your toy, enjoy it your way. It's all good.
Jack
Hi Jack,

I actually just tried Curtis Suter's design spreadsheet. I think it borrows heavily from Dr. Drela's methods which I have used a lot in the past for my own designs, but I'm not really all that familiar with the spreadsheet itself.

The main thing I was looking for with the dihedral was spiral stability and roll control.

I tend to agree with your assessment that the increased dihedral would make the glider a little more of a handful to land, especially in gusty conditions. However, I can just use the 8deg joiner set when the wind picks up and reserve the 12deg joiner set for hand launching into thermals close to the ground
Old Feb 03, 2009, 10:31 PM
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I saw Matt's wing tonight and it is just gorgeous, strong as titanium and beautifully built. Can't wait to see the whole thing all put together and flying.
Old Feb 17, 2009, 12:30 PM
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I'm getting excited, the wing is almost done. Just need to shape the wing tips and go over the whole thing with the fine grit and it'll be ready to cover.

I'm thinking of using pearl yellow monokote, anybody have any experience with the pearl colors?

Jack, I have a question about this picture:
https://www.rcgroups.com/forums/atta...mentid=2257515

Did you notch the tailboom to mount the fin or just attach the fin to the outside?
Old Feb 17, 2009, 05:41 PM
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Just received my short kit from Laser Arts. Looks nice. I'm sure glad this thread is here

The plan says "Yardbird" dated 7/20/2005. I sort of expected it to say Yardbird II. Is this the right plan, Jack?
Old Feb 17, 2009, 06:18 PM
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I'm sitting down with the plans and the materiel list and what I've ordered, trying to make certain I understand what goes where.

Someplace in the spar system I get disconnected. Did anyone ever do a rib cross section for the three panels that shows how the spar goes together? There are lots of pics, but I guess my head just extrapolate from the pics or something.

I guess the main spar is what is confusing me. Is it just a .042 cf bottom, vertical balsa web and .060 cf top?
Old Feb 17, 2009, 08:14 PM
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Quote:
Originally Posted by GaryO
I guess the main spar is what is confusing me. Is it just a .042 cf bottom, vertical balsa web and .060 cf top?
Yep, you got it. That confused me at first too.
Old Feb 17, 2009, 11:48 PM
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Shoe,

The tail boom isn't notched. It ends before the fin post to clear the belcrank for the stab.

Gary,

The spar caps are cf only, no wood, and are glued directly to the shear webs. Be sure to note the angle that must be sanded into the top of each shear web, to match the airfoil contour.

Jack
Old Feb 18, 2009, 11:35 AM
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tow hook & CG


alright... i'm moving along... getting ready to glue the pod all together, but first need to get the tow hook in there first.

so... what is a starting, recommended, or used CG point for this wing, and then where from that should the tow hook be placed? i got a adjustable tow hook from barry kennedy, it has about 5/8" travel. any good recommendations where to locate it in the fuse pod?

thanks!
matt
Old Feb 18, 2009, 02:27 PM
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Matt,

What kind of pod are you using?

JW
Old Feb 18, 2009, 02:30 PM
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Oh, by the way, mine is balanced at 4 7/8" behind the leading edge. I'd recommend starting at 4 5/8 and work back from there. I always start with the hook 15 degrees in front of the CG and work back from there. I usually don't have to move either CG or hook, much.

Jack
Old Feb 18, 2009, 02:54 PM
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i used the art hobby high aspect fuse pod, boom, and molded vertical stab... it seems real long, but compared to a Topaz fuse, the nose is about an inch longer than the Topaz, and with the rudder attached to the molded vertical stab, it is about 2 inches longer than the topaz. all with the wings leading edges lined up. with the rudder i made to go with this, it is 63 1/2" long from nose to TE of the rudder.

pardon my not understanding... but 15 degrees in front of the CG?? how do you measure that?

thanks
matt
Old Feb 18, 2009, 03:31 PM
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Make 2 right triangles from card stock. The other 2 angles are 15 and 75 degrees. Mark the CG on the bottom of the wing. I use tape, With the model upside down and the center section in place, place the triangles on the wing, next to the fuselage, with the 15-degree angle facing aft, the 90-degree forward, and the 75-degree up. Line up the 15-degree point with the CG on both sides. The aft side of the triangle now should be sweeping forward of the CG at 15 degrees. A stratight edge lined up across the fuselage will give you that 15-degree starting point.

JW

VERY nice radio installation...


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