Wednesday, June 29, 2011

T28 Trojan Pilot T-Shirt

The T28 North American Trojan is one of my favorite RC airplanes to fly. The full scale Trojan was used during by the Navy starting in the 50's as trainer for pilots. Today it's radio controlled little brother is made by Parkzone and is flown by many pilots including myself.

With very sturdy foam construction, mine has taken more than a few beatings and continues to be a blast to fly. This is also a great plane from those that like to tinker. Some have added flaps and retractable landing gear. Mine sports a eflite power 10 motor which gives it unlimited vertical climb. If you don't own one of these jewels, then it might be time to let your better half know that the Parkzone T28 Trojan is at the top your Christmas wish list. Or if you all ready have one, let her know you want a T28 RC Pilot shirt from Poker and Chaos.

Saturday, June 25, 2011

Senior Telemaster Build, Part One

Senior Telemaster RC Airplane
Photo by D. Reifsnider
After getting back into the hobby and flying a few RTF and foam planes, I decided I wanted to build my next RC plane. It had been more than 25 years since I had built a wood model, but I excited and anxious to again give it a shot . I decided on a classic kit,  the Telemaster Senior to use for my reintroduction to this lost art form. This German designed model has a long history having been first built sometime around 1967. Eventually, Hobby Lobby started importing them into the U.S.A. and they still produce the kits today as this is where I got my box of balsa from. If your interested in the STM's history you can read more about it here:
Telemaster PDF

Having ordered my kit, I set about collecting the basic tools and supplies that I would need for the build. First was a level surface that would except and hold the t-pins that are used to anchor the balsa parts over the plans as you build. For this I built a 2"x4" frame to attached a piece of 5/8" high density particle board, the kind cabinet maker use. The wing span on the Tele is 95" so I built my table 4 feet long to accommodate each wing panel. It might have been nice to have a larger table, but my space was limited. My original thought was to cover the table top with an acoustic ceiling tile as they are fairly level and will easily accept t-pins. Problem was I could not find a supply store that would sell me an individual tile, they all wanted me to buy a $70 box of tiles. So if the big wigs at Lowes or Home Depot are out there, take your box of tiles and... Well I digress. To solve this problem I chose to put a 1/8" layer of luan over the top and anchor it with small paneling nails. This worked fine.

Here is a list of the basic tools I scrounged up.

#11 X-Acto Knife and a box of 100 blades. Be sure to take a piece of tape and wrap it around the handle sticking the two ends of the tape together creating a flag. This will keep the knife from rolling off the table. It's not a pleasant sight to look down and see a knife sticking out of the top of your foot, ask me how I know.

Razor Saw, X-Acto makes one as does Zona. A mitre box is also nice to have. This saw and the knife will be your main tools for cutting all your wood.

T-Pins in various sizes. These are used to anchor parts together and down to the building board.

Clamps, lots of them. I found quite a few types of small clamps at Harbor Freight. While not the best quality, they are cheap. Another option would be a magnetic building board which I did use for assembling my fuselage, but I'll get to that later.

Glue, the instructions call for any type of wood glue. I used Titebond II as that's what I had on hand. If I had it to do over I believe I would have rather had the original Titebond formula as it's water soluble and excess glue clean up would be easier. I also used Zap gap filling CA in a few places where pieces were hard to get a clamp on. 30 minute epoxy is needed for joining the wing halves together if your building a one piece wing like I have.

Wax Paper and Scotch tape. Used to cover your plans as the wing, stab and fuselage are built directly over them.

Q-Tips and Paper Towels. Used to clean up excess glue squeeze out.

Sandpaper, in various grits from #60 to #150.  I mostly used 60grit as it is very course and shapes balsa quickly. The finer grades will be used prior to covering to get a smooth surface. I created sanding blocks by cutting strips of high density particle board 1-1/2"x8"x3/4 and used CA to glue the sandpaper to them. I also made a few smaller block using various sizes of hardwoods.

Power Tools, While the hand tools above will get you going and are are all you need for the majority of the build, you will need a hand drill and bits. A drill press is even nicer. My jigsaw came in very handy. I mounted it to a thin board and flipped it upside down on a couple of sawhorses to make it stationary (see photo below). This setup worked very well. I also used a dremel tool with with a cut off wheel and grinding to fabricate some of the aluminum pieces I used I needed.

After receiving my kit the next step was to cut up the plans into the different sections that I would need for building, wing panels, fuselage top and side views. I taped the first wing panel plan down to the table and covered it with wax paper. I looked all over God's green earth for transparent waxed paper that was wider than Reynold's Cut-Rrite brand of 11.9". It's not out there. So if any of the big wigs at Reynold's are out there, you can take your almost 12" wax paper and shove it up your... I digress again. Anyway, I pieced together the wax paper and covered the plans so that they would stay clean and could be reused. The other views I taped to the wall above the table so that I could refer to them throughout the build.

To get started, I had to take my X-Acto knife and cut around all the die cuts of the ribs. I then stacked them together and gang sanded them smooth.

I have to say that the die cutting in this kit looked like it was done with a garden trowel. It was terrible. The wood in the kit was also poor and I had to contact Hobby Lobby to get them to send me replacement sticks of some items. At this point is was basically just following the steps in the instruction manual. Anchor the spars to the building board and start gluing the ribs into place. One thing to note here, I found the plans to be a bad as the wood. The lines were extremely warped and twisted. so be sure you have a long straight edge to use when putting the spars down. Don't trust the lines on the drawings to be straight.

Here  are a few pictures of the progress on the wing.

Here the rear spar is pinned down and I'm using ribs to establish the location for the center spar and leading edge before I pin them down. I used a metal straight to align the trailing edge as the plan lines are not straight.

Once the spars, leading edge and trailing edge are located and pinned down, I then started working from one end to the other gluing the ribs into place. I used a square to be sure each rib was 90 degrees to the work surface.

My first modification to this model was to strengthen the wing by adding 1/2"x1/2"x3/32" triangle gussets to the ribs at the trailing edge. I added one at the top and bottom of each rib on both sides.

Wing Gussets
The inboard rib of each wing panel is angled towards the wing tip. This angle is established using a template on the drawings. Instead of cutting the template out of the plans, I laid a piece of paper over the plans and traced the outline of the template. I then used this pattern to create a balsa wood template to use for setting the center rib angle. I also wanted to do away with the rubber band mounting of the wing, so I created a center wing doubler out of 1/8" G10 material that has a tab that slides into a slot cut into the #2 bulkhead to hold the wing in the front. The rear of the wing will be held on with 1/4" bolts. The pictures below show the doubler being glued into place.

G10 Wing Doubler

The wing tips are glued into place using a template from the plans to set the correct angle. I also used this template to mark the tip angle on the struts so they could be cut to the proper angle.
Wing Tip Angle

Wing Tip Glued and Clamped

The original plans call for a single aileron servo with dual linkage to control both left and right ailerons.  I decided to change this and have separate servo for each aileron. This required that I box in a center portion of each wing in order to mount these servos.

Aileron Servo Mounting

Removable Aileron Servo Tray

Below you can see where I drilled holes and used green milkshake straws for a servo wire chase in the wing. 

Below you can see where I have glued the wing halves together and added balsa sheeting to the underside of the aft wing section.

Once the wing halves had been glued together, I wanted to reinforce the rear of the wing where it would be bolted to the fuselage. I did this by fabricating an aluminum brace that I glued at the rear of the wing.

Fabricated Brace

Installed Wing Brace

Next step was to move on to fabricating the tail feathers, better known as the stabilizer, elevator, fin and rudder. I will go over this in part two of this post.

  1. Part One, Wing <--YOU ARE HERE
  2. Part Two, Tail Feathers
  3. Part Three, Fuselage
  4. Part Four, Wing Struts
  5. Part Five, Wing Attachment
  6. Part Six, Power and Fuel