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Building Tips and technical articles. => 1/2 A building. => Topic started by: Ed Prohaska on September 03, 2009, 11:07:59 PM
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Here is a conversation piece, if nothing else: A fully take-apart Brodak .049 Basic Trainer. The finish is 100% Monokote. It's about 6 years old, with maybe 200 fights. Sixty of those were "training flights". It's been crashed a few times over grass, but nothing ever broke. With a hot Cox Black Widow or Norvel .061 it easily does inside loops and wingovers. I've had it inverted and done outside loops, but those are a little dicey with the lifting wing. A Brodak .061 is currently installed. When beam style engines are used a custom motor mount is added. I make it out of plywood and fuel proofed it with dope and clear Lustrekote. EWP
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This is pretty sweet!
Did you mod it into a take apart?
Robert
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Ed, I like what you did with your BBT. I'll bet it hauls the mail with that .061.
My Brodak Basic Trainer is beat up. It has a Cub .049A on it that has lasted through the many crashes. The fuselage broke just behind the engine mount a couple of times, after which I installed a couple of popsicle sticks mounted in slots that I cut in the fuselage.
The controls are set up with minimum deflection to teach kids to go round and round. It will not loop. Still, the only thing it needs is more kids. 8)
George
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It does "haul" with a hot Black Widow or Norvel .061 and 4X5 or 3X6 prop, but the Brodak .061 turned out to be relatively mild. You might think it would make a better trainer with a mild engine, but most of the training flights were done with the Norvel on 15% fuel and a 2-pitch prop (2-5 or 2-6). That slowed it down to a manageable speed, but maintained good line tension.
The remote tank (about 3/4 oz.) gives a 3.5 to 4 minute flight time. Lines are usually 38 feet X .012 inch cable. The .008 lines are too delicate for training. Dacron is probably best because it's cheap, doesn't kink and is easily replaced. An instructor would take 2 or 3 students to the center of the circle and each would get 5 to 10 laps of stick time before getting dizzy.
I'm a Brodak dealer and sold over a 100 of these kits, mostly on Ebay, but also about a dozen locally. I tried to do a nicer then normal job on mine so I could use it as a sales tool. Usually they are nailed together in an hour or 2, fuel proofed (sort of) with Lustrekote spray paint and flown the same day!
I added plywood hard points to mine where the wing and tail bolt on. The fin and rudder were initially held on with 3M clear vinyl tape, but later I glued them. The elevator is hinged via the wire and tubing method and must be removed to slide the stabilizer out. In the front I inlaid 3/16" basswood where the motor mount goes and added 1/64" plywood doublers. I also added a wire skid with a loop for stooge launching.
When I built the Basic Trainer I was getting into take-apart models and figured 1/2A would be a good place to start. EWP
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I love it. Have a kit hanging on the hook. I also have one the oldest gradaughter built. Can't get her to fly it. Thanks for the pictures. DOC Holliday