Power Line Hobbies U.S. Army Bird Dog

Dec 17, 2009 No Comments by

This fast-building favorite is “spot” on!

By Mike Gantt

See Photos Below

While at the RCX show this year I came across an interesting warbird subject from Power Line Hobbies, the U.S. Army Bird Dog. Also known as the L-19 and the O-1, this plane was built by Cessna way back in the late 1940s. While reading the included instructions I found that the actual name Bird Dog was chosen by means of a contest Cessna had to help identify the L-19 with its own original nomenclature. These scout planes were extremely useful for putting artillery in the correct areas by searching out targets, orbiting overhead and communicating the locations of artillery hits and misses. This information was then used as an adjustment of firing for maximum control and consistency. I can only imagine the courage it took to fly low and close to the battlefields as these pilots did for their day to day occupation. The Power Line Hobbies Bird Dog is built from lite-ply and balsa and covered in a heat-shrink film. This ARF is well supplied with the works: A brushless motor, ESC, servos and airframe are complimented with wire landing gear, steerable tailwheel, propeller, prop adapter, wing struts, foam wheels, canopy, front windshield, rear (or Omni-view) windshield and a hardware package with fasteners and control rods. There are even servo extensions and a Y-harness for the ailerons provided that can be used depending on your radio setup. A beginner can assemble and fly this plane, but I always recommend new pilots get help from an experienced builder/flyer.

Unique features

Cool factor number one is that all hinging has been done at the factory. It appears that CA-type hinges were used throughout. As with all planes which arrive this way, I tug on these connections in order to verify the solidity of bond. More good news is that the covering has been removed where the horizontal stabilizer meets the fuselage on both mating parts. Some thin CA will be required to attach those and the vertical fin/rudder. The steerable tailwheel is fixed to the rudder with CA as well, and I found that the hole for the tailwheel rod was predrilled. The included servos screw into precut slots; two fit into the fuselage and control the empennage, and two will screw into the wing and drive the ailerons. There is a string built inside each wing half which makes fishing the servo leads through them a piece of cake. The control rods feature a Z-bend on both ends, and an adjustable bend at one end for altering their respective lengths. These will attach to plastic control horns which are fastened to the airframe with screws and backer plates. Make sure to electronically center your servos prior to establishing all of the aforementioned connections. A stick mount is already in place on the fuselage’s nose and is really unique because it features a spring loaded mechanism which will soften a front end hit. The included motor is a 1300kV brushless outrunner and when I ran it up to WOT with the included prop, it produced 240 watts at 23 amps static. This seemed perfect for two reasons; the included esc is rated for 22 amps continuous and the plane should weigh in at close to 1 ½ pounds ready to fly. This translates into 160 watts per pound, a great amount of power for this model. I screwed the (built-in) motor mount to the carbon-fiber reinforced hardwood stick and then turned my attention to the remaining details. Screw in the cowl, windshields and wing struts with the provided wood screws, and add the landing gear. The mains are simple to complete. You will add the wheels to the wire gear, install the wheel collars, and slip the assembly into a precut slot on the bottom of the fuselage. A wood retainer and locking peg slide in and finish the process providing an easy to remove gear setup; perfect for different types of flying surfaces.  

Conclusion

Since the decals were all preinstalled, and much of the work is done for you, this model airplane builds rather fast. I spent about four hours and had the Bird Dog programmed to my transmitter and ready for its test flight. It is an easy build if you’ve constructed an ARF or two. If you haven’t, get some help from an experienced modeler and this project will sail smoothly. Even though the instructions have many photos, there are a couple of areas that could benefit from further explanation.  

IN THE AIR

With the Bird Dog balanced at the recommended center of gravity, I turned on the transmitter and plugged in my flight battery. I then double checked the control throws and made sure they operated in the correct directions as I moved the sticks. As noted, there is plenty of power available for a quick rollout, and as long as you taxi off of short grass or a paved surface, the plane breaks ground and takes to the air in as little as 10 feet. Ground control is easily maintained with the steerable tailwheel, and I was happy to see the plane roll so well. This gear system is well suited to the model. Landings are best performed with a slight bit of power on, and as you maintain the wings level, it settles in fairly well and touched down with a light bounce. The landing roll was almost as short as the take off roll.

General Flight Performance

Stability

I observed a little porpoise movement and it seemed like the servos weren’t centering perfectly. As long as I added a few small inputs, the plane would stop this action and is very easy to control.

Tracking

On the ground, the tracking is fine. The prop pushes plenty of air over the control surfaces and allows easy taxiing. In flight, after a few clicks of trim, the tracking is very manageable. It goes where pointed and will tend to right itself if you let a wing drop a bit.  

Aerobatics

Even though it is not designed as an aerobat, I could loop and roll this plane effortlessly. Stall turns, wingovers and tail slides are just as easy. I even managed to hang it on its prop for a few seconds, and believe it or not I snuck in a couple of knife-edge passes and snap rolls.

Glide and stall performance

Glides are sweet; slow and gentle with the nose pointed slightly toward Earth. Power off and watch as the Bird Dog coasts along just like a well-designed trainer should.

Pilot Debriefing

This plane would make a great electric trainer and looks really good in the air. Easy to control and maintain course, this airplane is also perfect for a Sunday chair flight. I have only seen a couple Bird Dog models at the field, so it is definitely an original “Bird” worth showing off. Since most everything needed is all in the box, the Bird Dog from Power Line Hobbies is an exceptional value!

Control throws:

Elevator: +/-3/4 in., 30% expo (low); +1 ¼ / -1 in.; 40% expo (high)

Aileron: +/-5/8 in., 25% expo (low); +/-7/8 in., 35% expo (high)

Rudder: +/-3/4 in. (low), no expo; +/-1 1/8 in.; 20% expo (high)

Specifications

Model: U.S. Army Bird Dog

Manufacturer/Distributor: Power Line Hobbies (powerlinehobbies.com)

Type: Electric trainer

Smallest flying area: football field

Ideal for: beginner to intermediate pilots

Wingspan: 47.2 in.

Wing area: 372 sq. in.

Ready-to-fly weight: 23 7/8 oz.

Wing loading: 9.2 oz./sq. ft.

Flight duration: 6-10 minutes

Price: $170

Gear used:

Drive system included: 1300kV brushless outrunner, 22 amp brushless ESC

Radio system used: JR 9303 DSM2, Spektrum AR 6100E, (4) included sub micro servos

Battery used: Thunder Power 3S 1320 ProLite

 

Scoreboard

+ Fast, friendly build

+Nice vintage warpla
ne looks

+Great value

-Instructions leave a little to be desired

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