Switcheroo (oz357)


Switcheroo (oz357) by Keith Laumer from Flying Models 1962 - plan thumbnail

About this Plan

Switcheroo. Free flight power model, multi-engined amphibian. Plan shows 3 motors: 1 on the nose and 2 on the wing pod.

Update 20/05/2021: Added article, thanks to RFJ.

Quote: "Capt Keith Laumer's Free-Flight Seaplane: Switcheroo.

Amphibious Tri-Engined .049 Flying Boat. One in the nose, two in double-ended push-pull nacelle. Ample power for ROW. Could convert to R/C. Full Size Timely Plan Available.

Switcheroo had just floated in to a smooth water landing on the bay. We fished her out, mopped a few drops of water off the hull and plugged in the wheel landing gear. The weighted nose block was quickly switched for an .09 nose engine and cowl - and Switcheroo was ready to go again - over land this time.

Using one, two, or (count 'em) three engines, mounting three-bladed Tornado nylon props, this versatile job is at home on land or water, turning in long, graceful flights in either version. Construction is straightforward, and features all-balsa hull and tail assembly, and a removeable pylon-mounted nacelle for easy storage and transport. The change from land to sea and back can be made in five minutes using only a screwdriver.

Start construction by cutting out bulkheads 1 and 3 from 1/8 plywood. Make and attach the 1/32 dural landing gear retainer plates, using thin rubber gaskets; then cut the remaining bulkheads.

Assemble the keel from parts 9, 10 and 11, and cement all bulkheads in position on it. Next add side stringers. (#8).

Cut two hull side panels from medium 1/16 balsa, making them slightly larger than the side view to insure coverage. Cement both panels in place against bulkheads 3 through 7. When dry, bring sides in and cement to bulkheads 1 and 2. Trim edges, and add bottom planking. Install tailskid and cut slots for the main landing gear.

Carefully seal and fuel-proof interior of hull, then plank top, except for portion between bulkheads 2 and 4. Cut two pylons from 1/8 plywood and join to nacelle firewalls, parts No.12. Add sides, parts No.13.

Cut 3/16 balsa slabs to fit against top of bulkhead 3, forming hatch cover. Notch to accommodate pylon, and shape in position on hull. Then cement to pylons, and add pylon side-doublers. Add nacelle bottom and ends, and shape.

Cut nose block for water use from pine or cypress, bore a 5/8 hole, and load, to equal weight of nose engine. Shape nose block to final contour, then remove, install engine, and build up and shape cowling. Add turbulators to bottom of hull.

Cut and install lower section of rudder and tail platform. Sand entire fuselage, clear dope, and sand again lightly. Apply tissue covering to fuselage if desired. Cut and shape rudder and elevator, clear dope, sand and join. Install tab using soft wire.

Cut and pre-assemble wing spars and leading edge. Use Testors 1/4 x 1 in trailing edge stock; notch upper surface of trailing edge at dihedral joints and crack to proper angle.

Cut ribs from medium 11/6 balsa. Shape all B ribs as a unit to insure uniformity. Assemble wing over plan, adding ribs to one panel at a time. Add leading edge and center-section planking and cap strips. Shape leading edge and sand entire wing structure; then clear dope and finish-sand. Daub all joints with cement/dope mixture for added strength.

Cover wing, wet paper, and when dry, clear dope. After checking over wing, hull, and tail assembly for rough spots, spray entire model with three coats of fuel-proof white dope, or if regular dope is used, apply a final coat of Comet fuel-proofer.

Add color trim and decals as desired, and optional plastic canopy. Bend two main L/G struts, and nose gear, and solder washers in place to retain wheels.

Test-glide the model over grass, with nacelle engines and weighted nose block installed. When flat glide is achieved, try a flight with tractor engine only, running at low speed. Then add second engine, making power adjustments as necessary.

Try your first overland flights with nose engine only. Make all necessary adjustments by correcting thrust angles, not by shifting CG, or readjusting incidence.

Water take-offs are easier on slightly choppy water, with both nacelle-mounted engines at top RPM. ROG is obtained easily on any one engine. With all three turning up. Switcheroo climbs like a jet!"

Supplementary file notes



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Switcheroo (oz357) by Keith Laumer from Flying Models 1962 - model pic


Switcheroo (oz357) by Keith Laumer from Flying Models 1962 - pic 003.jpg
Switcheroo (oz357) by Keith Laumer from Flying Models 1962 - pic 004.jpg
Switcheroo (oz357) by Keith Laumer from Flying Models 1962 - pic 005.jpg
Switcheroo (oz357) by Keith Laumer from Flying Models 1962 - pic 006.jpg
Switcheroo (oz357) by Keith Laumer from Flying Models 1962 - pic 007.jpg

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