Cessna L-19 Bird Dog (oz16033)

About this Plan

Cessna L-19 Bird Dog. Radio control scale model, for electric power with geared Speed 400 motor. Wingspan 40.3 in, wing area 201 sq in.

Quote: "Free Pull-out Plan. Speed 400 sport-scale park flyer. L-19 Bird Dog, by Rich Uravitch.

The Cessna L-19/O-1 Bird Dog was developed in response to an Army requirement for a two-place, all-metal Liaison/Observation aircraft to replace the aging Piper L-4 and Stinson L-5 inventory. Although originally built as Cessna's Model 305 in 1949, this great little warbird soldiered on well into the Vietnam conflict era, performing yeoman service in a variety of roles. Among the more exciting and way up on the pucker factor missions was that of the FAC or Forward Air Controller. These intrepid airmen flew their O-1's at altitudes where rocks and bottles could be considered SAM's, at airspeeds not much greater than some of today's higher performance RC models! While they were at it, they managed to mark the targets of opportunity with Willie Pete, white phosphorus rockets, so the Fast Movers could lay down their Mk 82's and other ordnance. These activities were truly NOT for the fainthearted or uninspired!

The explosive growth in electric propulsion systems for RC models was one of the motivators for me to design this model. Unlike glow or gas power, electrics let you really match the model to the propulsion system and obtain the desired flight performance. Props, gearboxes and batteries provide the means to go from slow flyer to hotliner to jets and cover everything in between.

When pondering what subject I'd like to do to use the popular geared Speed 400 package, I recalled one of my early free flight modeling adventures in the form of a 36 in span Berkeley Cessna L-19 Bird Dog (oz242) powered by a McCoy .049 diesel engine. I'm sure memory fades and time has provided some embellishment, but I do remember THAT model really flew well. So why not a slightly larger, e-powered version? Yeah, why not? So, here it is!

My design goals for this model were simple -just that, simple! It's all sheet balsa and lite ply and, once you've cut out the parts, can be framed up, to the point of cov-ering, in just a few hours spread across two or three evenings. In actu-ality, it took me less time to frame up than it did to cover and install the radio and power package.

The parts count on the Bird Dog is not high and building moves along quickly if you've got all the parts on hand when you start. The best approach with this, and any plans-built model, is to cut out all the parts and make your own 'kit.'

FUSELAGE: The key requirement in building the fuselage is to build it straight, and twist free. This is more easily accomplished if you accurately mark the fuselage sides with the longitudinal reference line and the for-mer position. Mark the farmers with the reference line position also.

Begin assem-bly by position-ing formers F2, 3 and 4 on the servo tray. Do not glue. Build up a left and right hand fuse-lage side by joining the side window area part with the main fuselage side. Glue the former/servo tray sub-assembly in position on the R.H. fuselage side. Add the LH fuselage side followed by formers F1, IP, F4A, 5, 6, and 7. Add the 1/8 sq stringers between F4A and F6, and formers F1 and IP. Bend the 3/32 music wire landing gear strut to the layout pro-vided in the plan and glue it securely to the forward side of former 2. Add the LGA and LGB parts to capture the wire. Glue a Vs square stringer in the notches in formers F6 forward to F2. This stringer extends aft from F6 and butts up against F7.

Now glue formers F1A, F2C, and F3A in position gluing them to both the fuselage sides and the Vs stringer. Maintain the lower contour shown on the plan. Continue the stringer forward to former 1. When you are satisfied that the fuselage to this point is square, add glue to the joints of the original F2, 3, 4 and servo tray assem-bly. Add the upper V]s balsa sheeting between Fl and IP and F4A and F6. Glue Vs sq. supports on the upper edge of the cabin structure between F2 and 3, and F3 and 4..."

Direct submission to Outerzone.

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