Sam-Rai Composite Thread
 

Sam San is now concentrating on his composite kit business.

Here is one of his Semi-Composite-Kits. His products fly great and are available at competitive prices.

Here's a link to this kit:

http://shop.sam-rairacing.com/SAM-RA...e-Kits_c24.htm

The composite versions are legal for the 426 class racer. They are not legal for 424 (Thunder Tiger) racing.

The wing weighs in at 16.75 ounces and modelers should have no problem building a racer at minimum weight.

I plan on finishing a couple other models before getting started on this one.

RE: Sam-Rai Composite Thread
 

It's time to get back to building after a few contests. The Albuquerque race cost me a Q500 racer.

In keeping with my philosophy to minimize building time I've chosen to reuse the tail surfaces, landing gear, and pushrods.

RE: Sam-Rai Composite Thread
 

I've gotten used to the following servo arrangement. The two in the back go to the "V" tail and the other goes to the engine kill.

A tray is made from 1/8" thick plywood. Use the kit provided tray as the basis for the widths and tabs. Locate the servos and switch as required.

Drill the holes for the servo mounting screws at this time.

RE: Sam-Rai Composite Thread
 

Lay out the fuselage sides, making sure to make a right and left hand side.

I attached the fuselage doublers with 3M77. Apply a coat of adhesive to both sides. Wait at least 30 seconds and then join parts together.

RE: Sam-Rai Composite Thread
 

Test fit parts and trim them as necessary to fit.

RE: Sam-Rai Composite Thread
 

A piece of wrapping paper was taped to the workbench to provide a building surface.

Draw a line down the length of the surface to provide a frame of reference.

Along the line identify where the formers will be located. I used a marker and identified the appropriate widths.

RE: Sam-Rai Composite Thread
 

"Gorilla" glue was used to attach parts.

Begin by dampening the surfaces with water.

Apply the glue to formers.

I then used rubber bands to clamp parts in place.

RE: Sam-Rai Composite Thread
 

The front firewall is squared by placing the nose to the wall and adjusting as required.

RE: Sam-Rai Composite Thread
 

The top wing mounting blocks have a tendency to slide around until the glue dries.

Double check the joint and insure that the fuselage is straight before leaving it to dry.

RE: Sam-Rai Composite Thread
 

I always like reading your threads. Thanks for shareing your tips.
Question...Doing the fuse doublers with spray 77 looks super quick. I never thought of that.
How does it hold up over time? Not that many of mine last too long.:)

RE: Sam-Rai Composite Thread
 

I've attached the doublers many ways. I don't notice any significant difference with the 3M77.

I've went back to the 3M77 to speed up construction.

RE: Sam-Rai Composite Thread
 

It is easier to drill the servo mounting holes prior to mounting the servo tray.

Here's how you can drill the holes after the tray is glued in place. Begin by turning the fuselage over to provide access to the bottom.

Mark the location of the screws with a sharp pencil. Remove the servos and drill accordingly.

RE: Sam-Rai Composite Thread
 

The fuselage top and bottom surfaces are sheeted with the provided 1/8" thick balsa sheets.

I glued on the sheeting with CA.

The bottom of the fuselage behind the motor firewall was left unsheeted. This provide access to the back of the firewall for installation of fiberglass or carbon fiber fabric.

RE: Sam-Rai Composite Thread
 

The nose moment is a little short and may cause you to add nose weight.

Lengthening the nose will reduce the amount of nose weight required. I added a 3/8" thick piece of plywood to lengthen the nose.

RE: Sam-Rai Composite Thread
 

The blind nuts are installed in the back of the firewall and pulled flush with the 6 x 32 bolts.

A drop of oil is applied to the bolts to keep glue from sticking.

Strips of carbon fiber were glued in place with medium CA.

RE: Sam-Rai Composite Thread
 

The landing gear was attached with button head bolts and blind nuts.

RE: Sam-Rai Composite Thread
 

After about 6 hours of work the fuselage looks like this.

RE: Sam-Rai Composite Thread
 

Align the wing to the fuselage and tape the wing on.

Drill, tap, and countersink for nylon bolts.

This step takes about an hour to complete.

RE: Sam-Rai Composite Thread
 

Next is making sure the tail surface is ready to attach.

I begin by identifying where to place the level.

There should be plenty of room for the torque rods.

RE: Sam-Rai Composite Thread
 

The wing is attached and parts are set on a flat surface. You block up the tail as necessary until the wing is level. An incidence meter is used to confirm that the wing is level.

The tail surface is checked for level with a simple string level. Adjust as required until parts are square and tack the tail in place with CA.

RE: Sam-Rai Composite Thread
 

Small pieces of balsa sheet are glued in place under the tail surface.

A piece of balsa is fitted and then glued between the "V".

RE: Sam-Rai Composite Thread
 

Use a sanding block to shape the fuselage as required.

RE: Sam-Rai Composite Thread
 

I reinforced the landing gear block with a piece of 4 ounce fiberglass cloth. The tail was reinforced with 1.6 ounce cloth.

RE: Sam-Rai Composite Thread
 

Spray a light amount of 3M77 to the wood to tack the fiberglass cloth in place. This time I used 1.1 ounce cloth.

RE: Sam-Rai Composite Thread
 

Three layers of 1.6 ounce cloth were applied over the nose to provide strength.