Great Lakes Trainer (oz10105)

About this Plan

Great Lakes Trainer. Radio control (or free flight) scale model biplane.

Quote: "Famous biplane of Lindy's Era returns as a great R/C flyer - even without radio she's a fine free flighter. Great Lakes Trainer, by William C Northrop.

This Great Lakes Sport Trainer was designed and first built in 1929 by the Great Lakes Aviation Corp. Though production continued for only four years, enough were turned out to make it still possible to come across one from time to time. Probably modelers have done more to preserve the memory of this pleasing little bipe than any individual or group.

Our R/C model presented here is a tolerant, stable, relaxing flyer that can be flown practically free flight with only an occasional tap on the transmitter button to remind it to stick around. Speaking of free flight, this is a good answer to the F/F flying scale situation. Reduce some wood sizes, spread out the ribs a little, bolt on a hot .049 or a warm .065 or .074 and you're all set.

If your interest is up to the boiling point, roll up your sleeves or call in your coolies and get to work on the fuselage. This is built in conventional manner (I'm showing my age, I guess this isn't conventional any more) with 1/4 sq longerons, 1/4 sq and 1/8 x 1/4 uprights and diagonals.

The liner of 1/16 thick plywood is added (contact cement works best here) before sides are joined. Bulkhead at B, cross braces at C, top cross brace at D, and a temporary cross brace at bottom D are used to start the assembly of fuselage sides. Allow this much to dry, watching alignment, before pulling ends together and inserting remaining cross pieces.

Add formers C through H. Be sure the smaller E-1 former is toward the tail. Stringers are next. Turtle-deck stringers which butt against E should be rock-hard 1/16 x to resist pull of covering material. Sides stringers are 1/16 x 3/16, tapering to 1/16 x 1/8 at 'B' and 1/16 sq at 'G.'

Cut cabane struts from 1/8 plywood. Form 1/16 wire struts and wing supports, bind and solder using ply struts as spacing guides. Now glue the ply struts to the wire cage and bind together with nylon or silk. Key the strut as-sembly to the body by cutting notches out of the ply liners. Leading edge of cabane assembly butts against bulkhead 'B'; 1/4 in balsa blocks fill in around struts to tie unit securely to body.

Forward decking of 1/16 balsa can now be put in place. I used 6 in wide stock and covered 'B' to 'E' in two sheets with a joint at 'D'. Contact cement did this without using one pin. Glue maple motor mounts and 'B' battery floor in place, using care to get exact alignment of mounts.

Before building up nose out 1/2 in sheet stock, mount motor in order to check clearances. Mounting system shown, us-ing aluminum tabs, allows minute changes of side thrust. Cut outline of nose block 'A' from solid or laminated stock, hollow out to clear needle valve, exhaust, fuel line, etc., then glue in place. Side and bottom blocks can now be added. A good strong glue for this pur-pose is Fullers or Elmers white glue. They dry clear, a little slower maybe, but rock hard. Cut another block to serve as removable hatch in top of nose. Notch to fit down over bulkhead between tank and 'B' batteries and hollow out to clear tank. Glue blocks inside front for hatch to rest on. Now nose can be carved to final shape while holding hatch in place using only your expendable fingers..."

Direct submission to Outerzone.

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