T-28 Trojan Scratch Build

Hello All! This is a Scratch Built T-28 Trojan I built using $Tree Foam.

Check out The Overview Video!

Here's a Flight video:

T-28 Specs:

Wingspan: 52"

Horizontal Stabilizer span: 18"

Length: 34" (From Spinner to Elevator)

Motor: Park 480 850kv w/ 10x4.7 Prop.

Battery: Turnigy 1800mAh 3S (7-8min. flights)

Reciever: OrangeRX R620

ESC: Turnigy 30A Plush

Servos: (4) Turnigy 9018MG

(If you want more specs, leave me a message)

Background Info

After buying and mastering my HZ Super Cub, I had to make a difficult decision. I had enough cash to either upgrade it to a brushless motor and get larger batteries, or I would buy the PZ T-28 Trojan. I really liked the way the T-28 looked, and wanted to buy it. But, for some reason I did not. Looking back, this was a decision that would change my take on the RC Hobby. After upgrading my Super Cub, I forgot to recheck the Center of Gravty, causing it to crash. I became very frustrated after this, but decided to scratch build a completely new plane, using my new motor( which was'nt damaged in the SC crash). This sent me down the scratch building path.

So after building 5 scatch built planes, I gained enough flying and building skills to return to the t-28 design. After I finished my CESSNA Trainer, I had enough money to buy another set of Electronics (Motor/ESC/Reciever/Servos). I wanted a warbird type of plane with a low wing and a large wingspan. I had already determined the max size of a wing that would fit in my car to be 52inches long. So I used this, and decided to use the standard length of a piece of foamboard, 30", for the fuselage length. 

Design

The first thing I did was to sketch many different designs of grid paper. Eventually, I decited on one that would be simple to build, and still resemble the T-28.

Construction

Next, I Drew out the fuselage bottom / side plates onto a piece of foamboard. The fuselage would be Square with 4" Sides and Bottom. The tail would taper to 1/2 inch. I then cut out and folded one side plate and glued it to the bottom. I Installed a bulkhead at the rear to hold the shape, and used 2 pieces of green unsulation foam for the firewall. 

Next, I put red duck tape on the front for the paint scheme, and put in popsicle sticks that will hold the landing gear on.

Next, I added a piece of foam in the middle to creat 2 "decks." The upper deck would hold the battery, and the lower deck would be cut out as to make room for the wing. The motor wires would also be kept in the lower deck out of the way. The Reciever is also glued on.

Here, I have taped on a picture of a US Navy Star Logo that I printed off. In the red you can see a hole for the ESC wires to go into the fuselage. The ESC will be mounted on the exterior of the plane. In the upper left, you can see a smaller model of this plane.

Next, I would have to solder the connectors to the ESC, and Motor wires. I wont go into depth on how to solder, but I basically used clothes pins to hold the wires and connectors together, then heated both up, and melted solder onto it. 

After soldering, I glued the ESC to the outside of the plane and ran the wires in through the hole. The Red ESC almost blends into the Red tape, which looks good! The number "004" represents this as the 4th plane I have completely scratch built, but it is the 6 plane I have partially scratch built. 

Now it was time for the motor mount. I used a 2 layer thick popsicle stick motor mount, that is gorilla glued andhot glued to the foam firewall.The motor wires will be ran through the hole in the bottom of the firewall. I removed the paper from the side plates and bottom plate where it meets the green foam to make a stronger connection.

After this, I made the top of the fuselage that would open to gain access to the battery compartment.

I used 4 screws to bold in the Park 480 850kv motor to the popsicle sticks. Then I put the 3 wires through the opening into the fuselage lower "deck."

I folded the other side up and glued it in place, then colored the top with red and black duck tape.

I glued in the elevator servo, and attached the horizontal stabilizer to the tail.

Next, I drew the Verticle stabilizer, cut it out, and put red tape on the non-moving part. The rudder is 2.5 inches wide.

After that, I glued on the Canopy. The front would be glued to the moving hatch, while the back would have velcro to hold down the hatch.

Next, would be the wing. This is the largest wing I've ever built. at the base it would be a 12" chord, tapering to 8" at the tip. The leading edge is straight. I first traced out all the measurements onto one piece of foam board, cut it out, then traces it onto a second to get two wing halves. Each half is 26" long. 

I made a foam spar 3 layers thick and used plenty of 5mm wooden sticks as support. The 2 aileron servos are wired, and glued in Before the wing is finished. I used 1 servo extention for each servo, then connected a Y adapter.

I poured plenty of gorilla and hot glue onto the spars, and folded the wing over. After drying, it was very solid and strong. I colored it with some more red and black duck tape.

Next, I Cut out the bottom of the fuselage where the wing would attach. The hole in the fuselage is for the aileron servo extention so it can connect to the reciever. 

The wing is attached using many rubberband rapped around 2 wooden dowells in the fuselage. 

Next was the landing gear. This was the most challenging part of this plane. I used 1/16 inch music wire, that I purchased at my local hobby store. This was the first time I tried to make my own landing gear.(In my previous planes I used pre-bend wire from the Super Cub Float Set). I did not realize how tough it is to bend and cut music wire! I tried using my pliers, but ended up breaking them! Eventually, I had to bend it back and forth until it finally snapped. To bend it, I found that drilling a small hole in my plywood table, then putting the wire in the hole and bending it worked fine. I really need some kind of vice, or something though. Here is the finished product! 

I used 2inch wheels I had, and hot glued zip ties onto the wire to hold the wheels in place. 

I then wrapped a bunch of small rubber bands around the popsicle sticks and to the wire to hold the landing gear on. After adding the pushrods, the plane was finished!

On the first flight, it had a bad tendency to pitch up. I believed it was tail heavy. I added some nose weight, but also angled the motor down a bit. I may have angled it too far down, because now it tends to pitch down when given throttle. I decited not to change the angle, but I added a small up-elevator mix in with the throttle. Now it flies OK, but not as well as I would have liked. The landing gear held up very well on the landings though!

Thanks a lot for reading, and watching!

-BrockAC

www.youtube.com/aplanerc