Pendulum Pete (oz831)


Pendulum Pete (oz831) by Keith Laumer from American Modeler 1957 - plan thumbnail

About this Plan

Pendulum Pete. Free flight IC model, with pendulum elevator control. Plan shows two types of gear, both tricycle and taildragger, and floats too. Also shows alternate wing construction to make a CL model.

Update 06/05/2021: Added article, thanks to RFJ.

Quote: "Your model lifts from the runway, eases into a right turn, builds up speed and the bank tightens until the wing is almost vertical; a crash seems certain ­ but not this time, Pendulum Pete is at the controls! Power cuts, the plane rolls out into a glide and drifts across the runway as if reluctant to touch down; Pete is holding her nose up for a three-point landing. On the next flight, with a little less right rudder, Pete will cruise in the purposeful manner of a controlled airplane, with steady climb and smooth approach glide.

After a few free flights, a little variety is in order; so out with Pete's control line wing, add a set of lines, and you're airborne again in two minutes with a fast and maneuverable sport job. And if you want to see how Pete will act with a tricycle gear (or a four-wheeler, just for fun), pop another gear in place - no tools needed. Pete flies nicely over land or water with floats installed, coming in on grass without a scratch.

If you've never seen a realistic float model touch down on water, bounce off, touch again with a dash of spray, and swing into the wind to wait for a pick-up, you owe it to yourself to let Pendulum Pete show you how it's done.

Construction? Simple! Fuselage is a simple box with three sheet balsa parts and four plywood bulkheads. Tail assembly is sheet balsa, and the two interchangeable wings feature one-piece tips and identical ribs.

Fuselage: Begun by cutting bulkheads 1, 2 and 4 from 1/8 plywood, # 6 from 1/16 plywood. Parts 5 and 10 are 1/8 sheet balsa, # 7 from 1/16 sheet balsa. Aluminum retainer plates for convertible landing gear are formed by clamping blanks of 1/32 aluminum over a strip of steel 1/16 x 5/8, tapping with a light hammer. They are trimmed, drilled, attached to bulkheads 1, 2, 4 and 6. (If fixed LG is desired, simply lace wire to proper bulkhead, using No. 30 linen thread, and cement binding.)

Two sides are laid out using hard 1/8 sq balsa. Cut two of each piece, assemble first side over plan (protect with waxed paper); second side is built directly over first.

While side assemblies are drying, bend pendulum support from 3/32 brass welding rod to exact size indicated. Pendulum is soft iron wire (a medium-size paper clip is ideal). Wire is wrapped around support shaft eight turns. A loop is formed at one end, the other trimmed to proper length. Lead 1/8 x 3/8 x 3/8 is soldered to long arm. Washer is soldered to support shaft behind pendulum, and pendulum retained by wheel collar or by pin inserted through small hole drilled in shaft end.

When thoroughly dry, sides are removed from plan, sanded smooth before separating, and joined on bulkheads 2 and 4, with plates attached. The firewall, part 1, is drilled for radial mount or notched for beams, to fit engine used. Mounting nuts are glued to rear of firewall or under beams and retained by strip of balsa glued over them. Firewall is installed; sides are joined at the rear (note bevel of rear posts). Parts 5 and 7 are assembled, 1/8 sq cross pieces added. Gussets are glued in place. Plywood plates are put on at front and rear of cabin roof. 1/16 sheet balsa planking is attached to bottom from bulkhead 1 to cross-member between stations. 2 and 3. First section of fuselage sides is filled with 1/8 sheet balsa. Interior of tank compartment is fuel-proofed and No. 1 Perfect Fuel Tank (or equal) installed, after which add sheet balsa covering.

Sheet balsa cowling is built up, side pieces first, then top and bottom, finally the nose. Allow rough cowl assembly to dry before shaping with sharp knife. Entire fuselage should be carefully sanded and coat of clear fuel proofer applied to planked surfaces. Depending on engine used cowl may be detached as unit or cut along thrust line so only top half is removable.

Pendulum support is glued in place and reinforced with strip of nylon glued over wire and to sides of 1/8 sq. balsa members at station 3. Front and rear wing mounting hooks of 1/16 wire are added. Entire fuselage, including planked surfaces, covered with light silkspan, wet, and clear fuel proofed.

Tail Assembly: Rudder and elevator are cut from medium hard 3/32 sheet balsa and sanded to streamlined shape. Rudder tab is cut from rudder and mounted using soft copper wire. Movable elevators are cut from stabilizer and elevator hinge and control horn wire bent from 1/32 piano wire. Locking pin plate is cut from tin can, soldered to control horn. Small cotter pins are slipped over hinge wire, and notches to receive them are cut in elevators - front edges of which are grooved to receive hinge wire, which is then glued securely.

Cotter pins are inserted in trailing edge of stabilizer. Elevator is clear doped and sanded smooth. Push rod should be bent to exact length and engaged in elevator horn before elevator is glued in place on fuselage. With fuselage in horizontal position elevator should rest horizontally. Pendulum arm may be bent slightly fore or aft to adjust this neutral setting. Glue rudder in place.

Wing: Free flight and control line wings employ identical leading edges, trailing edges, spars. Ribs are basically similar but control line ribs have two holes for lead-out wires and additional notch for leading edge reinforcement.

For free flight the spar is built first. Two identical spars are cut out in four pieces each from hard 1/16 balsa. A full-length spar pattern is cut from celluloid. One set of spar members is assembled and glued to celluloid; the other set is glued to other side of celluloid, forming three-lamination spar with celluloid in center.

When spar is completed rib positions are marked and 24 ribs added. Leading edge of 1/4 sq balsa is next assembled over plan, marked, and attached to front edges of ribs. Trailing edge, of pine or hard balsa, is cracked to proper dihedral angles and attached to rear ends of ribs. Tips, cut from 1/8 balsa, are added next and structure sanded preparatory to planking leading edge. Hard 1/32 balsa is used to cover top of wing from leading edge back to main spar.

This planking is carefully cut to size and attached in four pieces. Center section is covered from leading to trailing edge on both top and bottom surfaces. 1/32 x 3/32 hard balsa cap strips are installed to complete wing structure. Cap strips are glued first at leading edge, then at trailing edge; care must be exercised to ensure their contact with ribs full length. Entire wing is now carefully sanded.

Construction of control line wing is identical with that of free flight wing except for additional leading edge stiffener. It must also be noted that control line wing is flat and employs one piece leading edge, trailing edge and spar. Top center planking is not added until bellcrank is put in position. Plate of 1/8 plywood is installed in center section to receive bellcrank. Lead out wires are installed inside wing..."

Supplementary file notes



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Pendulum Pete (oz831) by Keith Laumer from American Modeler 1957 - model pic


Pendulum Pete (oz831) by Keith Laumer from American Modeler 1957 - pic 003.jpg
Pendulum Pete (oz831) by Keith Laumer from American Modeler 1957 - pic 004.jpg
Pendulum Pete (oz831) by Keith Laumer from American Modeler 1957 - pic 005.jpg
Pendulum Pete (oz831) by Keith Laumer from American Modeler 1957 - pic 006.jpg

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