Schweizer TG-3 ~ 1/3-scale model by Peter Goldsmith (Build Thread by JimD)

[JimD]

Link to Peter Goldsmith's website page for this model:

https://www.petergoldsmithdesigns.co...-tg3-1-3-scale

The TG-3 is the fourth model in Peter's giant scale sailplane series joining the 1/3-scale Slingsby Swallow & Skylark and the 40% Schweizer 1-26 models.



The model kit is densely packed in a 6"x12"x48" box and includes two large rolled sheets of full-size plans. These plans are really for reference and not to be used as a building template. We started our build by finding all of the fuselage parts and separating them from their carrier sheets. The parts were placed over the fuselage plan in their approximate locations to assist with understanding where all of the parts go.

[JimD]

We were intrigued by Peter's design and build plan for the fuselage, so we decided to start our build here.

There is "crutch" section that forms a plane which cuts the fuselage in half top and bottom. Start by establishing a straight reference line on your flat and level building board. It is very helpful to place something on your worksurface that pins can be pushed into. Some builders like sheetrock (drywall board) or Homasote Sound Board for this purpose. Cover the surface with wax paper of other similar non-stick material so your parts don't get glued to the building board!

The crutch parts need to be aligned with the centerline and check along its length to make sure that the right and left sides are equal distance from the centerline.

[JimD]

The formers have tabs that fit into slots in the crutch base plate. Note that they are NOT perpendicular to the base plate. Peter provides an angle gauge to set these parts into place at the correct angle.

[JimD]

[JimD]

Scrap hardwood stick, binder clips, rubber bands, and bricks make useful tools to assist in keeps parts in place. In the picture above, we used a hardwood stick to keep the plywood former from bending while fabricating the dowel roll bar structure.

The upper fuselage parts continue to be added as we progress front the front to the back.

[JimD]

[JimD]

[JimD]

Pieces of scrap 1/32" plywood were used as shims to help set the spacing around the canopy frames. Strips of wax paper were used to prevent gluing the canopy parts to the fuselage.

[BryanB]

Really love your build threads Jim. Thanks for doing these.

[JimD]

It has been quite a journey this past year and four months...have built and flown four of Peter's designs, 40% 1-26, 33% Swallow, 33% Skylark, and Sapphire. Have built three other of Peter's designs and have them nearly ready to fly, the 33% TG-3, the Cmelak tow plane and the RES Foxbat sailplane. Also have Gunny's 33% 2-33 nearly completed.

[JimD]

While the fuselage is flat and level on the worksurface, the fin can be added. Allow the aft fuselage to overhang the workbench so the lower part of the fin can extend below the bench top. Sandpaper wrapped around a piece of dowel helps angle the fin ribs for a better fit of its dowel leading edge.

NOTE:

We built the fin separate form the fuselage as shown below. When we attached it to the fuselage, we somehow induced a bend in the 1/8" fin post! This was corrected by cutting the fin2 rib away from the former it sits on at the trailing edge of the stab. This allowed the fin post to straighten, but caused the leading edge of the fin to have a larger space between it and the top of the stab. This was just a cosmetic problem and not serious at all. The space was eliminated by adding a scrap piece of balsa to the bottom of the fin2 rib and leading edge dowel.

My recommendation is to do what Peter suggested, install the fin post to the fuselage, make sure it is straight, then add the ribs. In other words, build the fin on the fuselage instead of separately.







The three pieces of thick balsa that form the fin trailing edge and the rudder leading edge were held together with temporary wooden dowel pins and used to keep the 1/8" fin post straight.

Note that the bottom of the fin post extends below the workbench surface while the fuselage sits straight and level. This technique allows the stab and fin to be aligned properly while the fuselage is securely held in place.

[JimD]

This is also a good place to build the stab so it can be mated to the fuselage while the fuselage is firmly sitting on the workbench is a straight and level configuration. Start by aligning the two balsa stab TE pieces and aligning them on a straight line. Find the ribs and the plywood joiner part.









Prepare the lower center section sheeting by adding the elevator servo mounting parts. We started with the top sheeting and then added the bottom panels.






Apply Speed Bond glue to both surfaces, spread it into a thin layer, let it dry to clear, then iron parts together.












.

[JimD]

Check that the stab slides under the leading edge of the fin, then align stab with fuselage and drill a 1/16" pilot hole. Stick a piece of 1/16" music wire through this hole, double check the alignment, drill rear pilot hole. Remove stab and check to see where these pilot holes penetrated the stab platform. Once satisfied with these being on the centerline, put the stab back in place with the 1/16" pieces of music wire. Now remove one piece and drill out the hole with the size needed for the stab mounting bolts. Double check alignment and then drill out the other. Next, add the blind nut to the underside of the stab mounting plate.

[JimD]

Next, add the finishing touches to the stab and build the elevators.

[JimD]

The rudder is built in a similar fashion to the elevators. The thick balsa leading edge gets sanded to a "V" shape to allow for the hinge line to have sufficient side-to-side travel. Likewise on the elevators.

[wesryman]

Hi Jim. The plans show R1 (large ply vertical piece at bottom of rudder) and R2 touching. On mine there is a gap. In the first picture of rudder construction above it looks like you have added a piece to the top edge of R1 so it touches R2, is that what I’m seeing? I can add a piece like you did, just trying to make sure. Thanks

[JimD]

Yes, there was a gap on mine and we added a piece of scrap balsa to fill it in. Peter and I talked about that issue and a couple of other small things. He reviewed his CAD plan files and cut files and made corrections, but some parts for early kits may have slipped through.

[wesryman]

Ok. Thanks. No big deal just wanted to be sure before glue got applied. Thanks again

[JimD]

Now we return to our regularly scheduled program!

Where were we...ah yes, the canopy frames. Time to add the piano hinge to the front canopy. This metal hinge needs to be cut down. We used a cutoff wheel on our Dremel tool.





Next, the rare earth magnets are added to hold the canopy closed.