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Old May 03, 2011, 01:41 AM
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atesus's Avatar
Los Gatos, CA
Joined Aug 2009
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I gathered the wing parts. There may a few more that I missed but I have the main ones to start putting the center wing panel together.

Miles uses a built-up trailing edge. In order to obtain the proper profile, the inner surfaces of the upper and lower TE sheeting need to be thinned starting from where the ribs end, to a point at the back of the wing. In the second photo, the areas to be sanded are marked. The instructions recommend to go down to 1/32" at the back edge, but the drawings show almost a point. Using my bar sander and checking the progress frequently, I thinned the back edge to somewhere in between the two, like 1/64"
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Old May 03, 2011, 01:54 AM
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Los Gatos, CA
Joined Aug 2009
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I assembled the bottom LE and TE sheeting around the plywood wing center piece and glued in place. I noticed a minor mismatch in the way the LE pieces fit the plywood center piece. While trying to improve the fit, I got a little carried away and ended up with a 1-1.5mm gap between the L/R LE sheetings. No worries though, this is not a joint which needs to be extra strong, I will fill it up with scrap balsa later.

Most of the cap strip notches lined up perfectly between the LE and TE, except the outer two on the LE sheeting. I will trim them to match the TE.

I cut and trimmed the bottom cap strips and glued them in place.

I realize that the now tapered TE sheeting is not transitioning to the plywood piece nicely since I didn't sand the plywood. I will sand it and smoothen the joint.
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Old May 04, 2011, 03:15 AM
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Los Gatos, CA
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At this point there's no real need to be building over the plans, so I removed the plans and laid the plastic sheet directly on my building board. To protect the building board I use a dry cleaning bag which works nicely with wood glues, and with CA and epoxy as well.

The bottom of the ribs aft of the main spar is flat whereas the front part curves up towards the LE. One way of building this wing is to glue the flat section aft of the main spar first, then remove the assembly from the building board and to bend & glue the LE sheeting to the curved part of the ribs using thin CA. Since I'm trying to avoid CA glues I decided to try something different.

I placed wet paper towels on the underside of the LE sheeting. Once wet, the sheeting curves up. I then pinned the wing's lower structure down, and began adding the ribs. I was hoping that I could pin the ribs in place and move quickly from rib to rib but I quickly realized that this wasn't quite possible. It wasn't straightforward to reliably pin down the ribs without any gaps with the sheeting. I had to hold each rib down by hand, until the glue grabbed, a good 4-5 minutes per rib . After over an hour I was done, so it wasn't too bad after all... In any event, I'm satisfied with the results. I'm intending to bite the bullet and finish the remaining wing sections using the same approach for the sake of avoiding CA glues.
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Old May 04, 2011, 11:38 PM
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Sunnyvale, CA
Joined Feb 2002
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Great build thread. I admire your work.

Don
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Old May 06, 2011, 12:56 AM
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Los Gatos, CA
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Thank you Don .

The center 3 rib bays get extra 4mm thick shear webbing between the spars. I trimmed and installed those to fit with no gaps in this center part of the wing which will be subject to highest stress. I glued the top spar in place. I sanded the 1.5mm plywood shear webs of the middle bay to correct height and glued them in place. Test fitting showed that the balsa shear webs which will be used in the rest of the wing are also too tall but it's easier to sand those down altogether after installing them.

I sanded the TE of the plywood wing center piece to smoothly transition to the wing TE. I was a bit overambitious on the left side , nothing a bit of filler can't correct...

I was unable to locate the hardwood parts, I'm not sure if they were missing in the kit box or maybe I've misplaced them. Anyways, a quick trip to Home Depot yielded enough 1/2" sq hardwood for twenty Miles' for $1.50. I cut the wing bolt housings from the hardwood stock and shaped them to follow the profile of the 3mm center rib sections and glued all of them in place. I installed the rest of the shear webs with the exception of the outer two bays where I'll need access to install the joiners.
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Old May 06, 2011, 10:38 AM
that's gonna hurt...
USA, CA, San Jose
Joined May 2005
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Thanks for the great build thread, but I'm confused .... I thought it was going to move slooooowly

Bruce
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Old May 06, 2011, 01:16 PM
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Los Gatos, CA
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Well... I was extrapolating from the only other laser cut glider (GL) that I built, which had poor fitting parts and took me nearly 5 months to complete. Here the parts fit accurately, very minor trimming was required so far. It seem like most of my building time is spent while waiting for the glue to dry .
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Old May 11, 2011, 01:24 AM
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San Jose, Ca
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Quote:
Originally Posted by Don Cohn View Post
Great build thread. I admire your work.

Don
+1, great job, uhhhh nice clamps, a type and sorce if you can
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Old May 11, 2011, 09:44 AM
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Los Gatos, CA
Joined Aug 2009
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Hi balmy_breeze, the clamps with the rubber bands seen in the last picture are "Hayes Small Clamp 1-3/8inch" from Tower Hobbies. The other type seen in the second picture is the "3inch Spring Clamp Tool" from Hobby King. Harbor Freight also sells many types of clamps which can be used for our purposes for pretty decent prices.
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Old May 19, 2011, 02:07 AM
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Los Gatos, CA
Joined Aug 2009
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Back to work after some lull in the activities...

I glued the half-size doublers to the outermost ribs with spoiler notches (W6).

I started the wing joiner installation. The joiner tube mainly rests on the plywood shear web in the last rib bay and partially on the balsa shear web in the bay next to last, both aft of the spars. I glued those two shear webs in place.

Using the angled side of the plywood shear web as the gauge, I installed the last rib (W10) in place, handling it carefully as it is fairly weak in the center due to the opening for the joiner tube.

Once things were dry, I roughly trimmed the spar to proper length.

The wing joiners are pretty beefy and heavy. At one point I was tempted to let go of the joined supplied in the kit and make a one piece wing as I'm OK handling my other 2M glider's one piece wing without any troubles. I decided against the idea when I realized that I would have to give up the ballast tube which is accessed through the first polyhedral break .
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Old May 19, 2011, 02:26 AM
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Los Gatos, CA
Joined Aug 2009
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I sanded one end of the joiner tubes to match the first polyhedral angle and I plugged up the other end to avoid glue getting into the tubes.

I installed a piece of balsa between the spars, right after the joiner tubes, to act as a glue dam. I "borrowed" this idea from Robglover's build thread.
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Old May 19, 2011, 02:49 AM
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I roughened the surfaces of the tubes with coarse sandpaper to improve adhesion and cleaned the tubes with alcohol.

I mixed some 20min epoxy with 20% or so microballoons. I'm using the microballoons not so much for weight savings but to adjust the consistency of the mixture. This way it will be easier to pour it where I want .

The lower and back sides of the joiner tube rest against the lower spar and the plywood shear web respectively, so it's not quite possible for the glue to get into that area once the tube is inserted in place. For that reason I poured some glue to that area before inserting the tube. Now this is all done with the wing propped up on its trailing edge, with the leading edge pointing up.

Once the tube was installed in its place, I plugged up the two holes left on the rib, between the lower spar and the tube, with triangular wedges that I had cut from 4mm balsa scraps. This will avoid the epoxy mixture from oozing out of those holes. I'll trim these wedges later.

I poured the epoxy mixture between the spars to cover the entire joiner tube. The mixture is thin enough to flow through the gap between the top spar and the tube, and to fill the voids in the back.

I finished the joiner tube installation by gluing the last two shear webs in place.
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Old May 19, 2011, 08:23 AM
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Cupertino, CA
Joined Dec 2008
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Your photos are as beautiful as your assembly... nice work!
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Old May 25, 2011, 01:57 AM
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Los Gatos, CA
Joined Aug 2009
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Thank you Noel

I installed the ballast tube and glued it in place at each rib location. I was avoiding CA glues up to this point but I wasn't going to mix epoxy for this purpose .

Getting ready to apply the leading edge sheeting. I glued the two interlocking sheeting pieces together and while that was drying, I sanded the shear webs flush with the top spar. I had already trimmed off the shear webs with a razor blade so minimal sanding was needed.

I cut and stuck sections of masking tape to lower sheeting and readied them to be wrapped around the D-box in the next step. I applied glue to the spar and the ribs and without delay, I installed the top sheeting and secured it in place using the masking tapes. For good measure, I also put weight on the assembly as it dried.
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Old May 25, 2011, 02:05 AM
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Los Gatos, CA
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The sheeting is a couple mm longer than the ribs, it needs to be trimmed back flush with the front of the ribs.

I used a mini plane to shave off most of the material, followed by sanding with the bar sander.

I glued the laser cut LE stock in place and secured it with masking tape.
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