Iron Dog

The thin plywood hatch mounting rails are glued to the bottom (underside) of the sheeting with a combination of medium and thin CA.




(Tim states that this next step is unnecessary, so consider this optional.) We then used small pieces of triangle-stock to reinforce the security of the these mounting rails to surrounding structure, as pictured below. Sand any excess tri-stock away.

Iron Dog

With the aileron hatches defined, it is time to run the aileron extension wire through the panel. We are choosing to splice and solder a length of servo wire between the servo and the lead, rather than use a prefabricated servo extension. Whichever method you prefer, run the length of wire (or long extension)through the internal cut-outs within each rib, from the root to the hatch.



Tape both ends of the wire in-place so it doesn't pull through one end, or the other, before the wing construction process is complete.

Iron Dog

With the servo wire extension in-place, the last section of wing sheeting is glued in:

Trial-fit the final top sheeting piece, and sand/trim as necessary for a proper fit.

Iron Dog

As with the prior sheeting pieces, spray the inside portion of the sheeting piece with CA accelerator.

Apply thick CA to the spars and ribs.



Carefully, but quickly, press the sheeting in-place, starting from the apex of the piece (at the tip), towards the wider end (at the root).

Iron Dog

Complete the other panel in the same manner.


In these pics, and those in the 3 posts above, I (Ollie) demonstrate the steps described. See Jake . . . I CAN build! (That emoji is me giving you an extra wet, sloppy,and loud "raspberry", my friend!)

Iron Dog

Eric presses his final sheeting piece in place, as well.



Tim is done with this step, so he snaps a picture of both Eric and I, as we complete our second panel.

Iron Dog

Wing-tip blocks are thick CA'd to the panel. We got so involved that we forgot to take pictures of much of this part of the fabrication process. Essentially, we used three thicknesses of sheet. The grain of the middle piece runs parallel to the sheeting, with the top and botttom pieces running perpendicular. Thus, making balsa "plywood." At the time I finally remembered to take a picture, we already had ours rough-sanded to shape.


The only picture of the rough block is this poor resolution pic, as I photo-bomb Eric's gluing his sheeting with my wing panel. The second picture is what mine looked like when I finally realized I'd better start taking quality pictures. It is already rough-shaped after using a razor plane, by this point.



Tim final-sands his tips.

Iron Dog

Tim holds his two panels together to get an idea of what the finished wing will look like.





Tim is pretty excited that the CzechMate is finally taking shape! (Well, that and my music selection that we rock-out to each day of our build. The rolling stereo cart is behind him.)

Iron Dog

Eric and I also can't resist holding our panels together to better envision the completed wing, as well.

Iron Dog

Temporarily secure the aileron hatch, centered within the hatch opening, to the sheeting with tape. Drill the pilot holes for the hatches button-head screws. Repeat for the other panel.


Eric demonstrates on his first panel.

Iron Dog

My first panel's hatch taped.



Pilot holes drilled in my second panel.



Eric's grandfather, Greg, came all the way down from Redding to join us for the build on Saturday. He bought one of the other prototype CzechMate kits, as well; so wanted to witness some of the techniques used in its construction, as well as spend time with us.

Tim uses an allen wrench to install the button-head screws, while Eric drills the pilot holes in his second panel.

Iron Dog

It's finally time to join the wing panels!

I "refreshed" the airfoil centerline marks that were largely sanded away in places to ensure I could align the wing halves appropriately. These marks on the leading edge are references to better ensure that both halves would have the same angle of attack, after being joined. (If one wing has a higher angle of attack than the other, it will stall, first -- thus potentially dropping a wingtip on landing.)




Mix a batch of 30-minute epoxy and use a small flux brush to apply it evenly to both root ribs. Align the halves; then secure with tape and/or pins.


Greg assists Tim in applying epoxy and Eric observes the step that he is about to perform, next.




Tim aligns his wing halves, and holds them in-place ,as Eric tapes the halves together for him.

Iron Dog

While Eric and Tim taped their halves together, I chose to pin mine. (Each T-pin is placed at alternating angles to the center ribs.)

MFLOOD3800

My Feedback: (51)

Glad to see you all back at it, I've missed your posts Ollie.
It was great talking with you guys on Saturday.

Iron Dog

Tim displays my wing so I can take a picture.



Eric proudly displays his joined wing.



Tim's joined wing, set aside to cure.

Iron Dog

Great talking to you, too, Marty. I've missed you, and hope to see you soon. Sounds like you already have a busy race schedule, but any chance you'll be able to make it to the Big Kahuna race next month?

I've enjoyed following your Tsunami build, as well. Sorry we fell behind your progess. It has been difficult getting all three of us free for the same day, on a consistent basis, lately. Work has been kicking our butts, the last few weeks. But, we met last Saturday, and plan to again, this Saturday . . . so, stay tuned.

MFLOOD3800

My Feedback: (51)

Ollie,
Unfortunately I wont make the Sams April race.
I am planning on the YS / Trashman and Redding race though.

I have been slammed with work, travel and Ministry to the point I work on planes early or late, and try to make as many races that are aligned with my work schedule and that location.

The next 3 weeks are all on the books for Club racing, Q40 and Warbird racing - so Im excited to venture into all 3 racing types so early on.

Its all good but I cant wait to retire

FlyerInOKC

My Feedback: (6)

I'm surprised the wing halves are butt joined and there isn't at least 1 plywood joiner slotted into the wing to reinforce the joint.

Iron Dog

Even with larger race planes, I have yet to have a failure at the wing center section; or anywhere else for that matter. But that is because I use spruce spars and I fiberglass the center section appropriately. The Spruce doesn't compress -- and therefore collapse, causing the wing to fold -- under the G forces, like balsa would. (I have built planes for pilots in all three race classes, in this manner . . . "Yes," even several Gold planes. And my father-in-law also builds airplanes in this manner, and is a former gold class season champion, in his own right, as well as building for other very successful Gold pilots.)

If a larger and heavier airplane can handle these greater stresses magnified even further by G forces, then I am very confident that a smaller, lighter airplane, such as this one will handle them just fine.

But, there is no reason that a builder wanting that extra bit of security and peace of mind, couldn't use an exacto knife and a ruler lined-up with the top and bottom spars to cut a quarter inch wide slot between the spars and insert a dihedral brace, if so desired. (Now, bear in mind that I have a reputation for "overbuilding," and even I think this is excessive, under the circumstances, and an unnecessary addition of weight. ��)

tdstaf

My Feedback: (11)

Like Ollie said I also have not yet had a wing fail in the center. A dihedral brace only usually extends to the second wing rib anyway and typically this is where the wing fails at the fuselage edge and wing top sheeting at high G loading. Most often then not the wing rib was not located directly under the fuselage edge forcing the sheeting to be crushed thus causing its failure.

FlyerInOKC

My Feedback: (6)

I guess I'm thinking more in the terms of what I normally build sport and scale designs that normally use dihedral braces with or without fiberglass on the center joint.. I guess I take more of a belt and suspenders approach.

Iron Dog

With the wing panels joined and set aside to cure, Tim hopped on my table saw and started ripping two 2" wide strips of 3/32" balsa for each of us, and a bunch of 1/2" wide strips. These will be used to begin planking the top half of the fuselage.


For safety, Tim uses a "push-stick" to cut the 1/2" wide strips in the second picture.

Iron Dog

Sheeting/planking the top half of the fuse begins with adhering the bottom of the 2" wide sheet to the 1/4 x 1/4"longerons. Run a thin line of medium CA the length of this sheet, about 1/8" from what will be the bottom edge. Align the trailing edge of the sheet just slightly overhanging the rear edge of the fuse; allowing the majority of the overhang of the sheeting to extend beyond the the front. Starting at the rear, and working towards the front, begin pressing the sheet in contact with the longeron. (Make sure the sheet is flush with the bottom of the work surface.)

Glue the other 2" wide sheet to the other side, in the same manner.

Iron Dog

Apply thick CA to the edge of fuse formers where they will contact the sheeting. Press and hold the sheeting against the fuse formers, until the CA sets.


I hold the sheeting in contact with the formers until the CA sets.

Iron Dog

Eric, gluing his sheeting in place.