HANGAR 9: T-34 ARF

Model Airplane News, Oct 2004 by Roy, Rodney

A military trainer turned multi-capable ARF

Built by Beechcraft, the T-34 Mentor was the U.S. military's primary trainer during the 1950s. So if you know someone who was a pilot in the U.S. Navy, Air Force, Marines, or Coast Guard during the Iron Curtin or Vietnam War era, they most likely learned how to fly in a T-34 Mentor. The Hangar 9 ARF version is reminiscent of the planes that buzzed over Pensacola in the '60s, as it retains not only the full-size Mentor's scale look but also its excellent sport aerobatic performance.

WHAT'S IN THE BOX

There is no doubt in my mind that ARFs are getting better, and the T-34 proves it. Its balsa and ply construction comes fully covered in "Cub" yellow and black Ultracote. The kit comes with just about everything you need to complete it, including the fuel tank, a generous hardware supply, all pushrods and a 3-wheel gear; a complete retract gear assembly is available as an option. You need only supply a radio, an engine, a propeller and spinner. The instruction booklet is very well-written and has many detailed photos and diagrams that cover all stages of assembly.

ASSEMBLY

One of the first things I do on most ARFs is to reshrink the covering. This is not the fault of the covering or the manufacturer; it's just the nature of heat-shrink covering when it undergoes temperature changes during shipping.

The first thing to assemble is the wing. After I assembled the dihedral braces with 30-minute epoxy, I test-fit the wing panels. My dihedral braces fit perfectly. Each aileron is controlled by its own servo, and there are cutouts in each wing panel for the servos. All I had to do was remove the covering over the cutouts. There wasn't any string in the wing for the servo wires, so I strung one string in each wing panel before I glued them together because it is much easier to do before the wings are joined. I found that 9-inch extensions (plus a Y-harness) were long enough to reach the receiver. In the wing, where the servo lead and the extension connect, I tied them together with dental floss to eliminate any chance of their coming apart in flight. Next, I used some 30-minute epoxy to join the wing halves.

Once the wing was all set to go, I trial-fit it to the fuselage and was pleased that it lined up perfectly. The mounting holes for the wing hold-down bolts lined up exactly with the blind nuts in the fuselage. The next step is to attach the ailerons with the supplied CA hinges. The slots have already been cut. One thing I like to do is run a 3/32-inch drill bit in the center of the slot to allow better CA flow. I mounted the servos in the wing panels and then installed the control horns. Next, I assembled the control rods. One end is attached with a supplied nylon clevis, and then you have to mark the servo end, make a 90-degree bend and attach this to the servo horn with a supplied link. This way, the adjustments are easy to make. All that was left to do was to drop in the landing gear. The fixed gear fits nicely into place. The wheel wells are already cut into the wing panels, so if you want to install retracts instead of the fixed gear, all you need to do is cut away the Ultracote covering and bolt the Hangar 9 units into place. It's good to have a choice.

* Tail. When you assemble the tail, you first have to drill a hole in the horizontal stabilizer. Be careful when you do this; the rudder-torque control rod will pass through this hole. I found that the hole had to be enlarged slightly to facilitate installing the rod through the stabilizer. I then dry-fit all the parts to make sure that they fit and were aligned properly. Once this was done, I marked the section of covering that I would have to remove. When you install the tail parts, you must remove covering; be careful not to weaken the parts by scoring the wood. If you pull the covering up against the blade edge, a single-edge razor blade works well. When the parts are glued in, it is time for the elevator halves to be installed with CA hinges. The elevator halves require a joiner wire to be installed. Make sure that it is straight before you glue it into place.

FUSELAGE

Now it is decision time: retracts or fixed gear. Thorough instructions are provided for both methods. I chose the fixed gear because I wanted to get the plane in the air sooner, but I think I will change it because I feel that the model looks a lot better in flight with the gear up. Be careful with the covering that needs to be removed. Instead of cutting out the entire wheel-well area, I cut the wing carefully so the fixed gear just fit. Pay particular attention to the nose; the covering is not fastened to anything in the cowl area. I ended up gluing a small piece of balsa to act as a filler strip for the covering to be ironed to.

* Engine. Next comes the engine installation. The instructions direct you to draw vertical and horizontal centerlines on the engine-mounting spacer. On my model, the lines were already marked, so this was unnecessary. The extensive engine-mounting instructions will help people who have not done this type of airplane before. I tend to deviate from the instructions when I attach the engine to the engine mounts. I always use holts and locknuts rather then sheet-metal screws. This is just my preference. When I drill the mounts, I always use a drill press to ensure that the holes are perfectly straight. The instructions only show how to mount a 2-stroke engine, and I feel that is a shortcoming of most manufacturers. As I was using a Saito .65 4-stroke, I had to rely on past experience to know what to do. A hole has to be drilled in the firewall for the throttle pushrod. Going through the firewall isn't a problem, but because there is a bulkhead that must be drilled as well, I used a long drill bit for this.