Foam Learjet (oz6791)

About this Plan

Foam Learjet. Radio control sport-scale model. For 1/2A power.

Quote: "Would you believe a .60 size model powered by a .051? When this foam Learjet makes a low, fast pass down the field you can hardly tell it from the real thing. The Tee Dee in the tail is virtually impossible to see.

Look around at the models at the flying fields these days and you will see either jumbo airplanes or peanut planes, and if you have a small engine you're stuck with building a mini-size plane, right? Look again! Would you believe this .60 size plane flies with a 1/2A engine?

This Stand-Off Scale of a Lear Jet is not much to look at up close but, make a 4 foot high pass down the runway and you'll really draw the attention!

The small engine on this size plane isn't noticeable in flight. You will also find, because of the large size, it takes two hands to launch. Climb-outs are similar to a powered glider. Most stalls are straight ahead, only the most violent stalls will make a wing fall. Once the engine quits, it glides quite well. With the nose flared up, landings seem to stretch forever.

If you like to fly them low and fast. guesstimated speed on level flight would be about 30 miles per hour. It has been flown in 20 mph winds but it isn't the pleasure it is on a calm evening.

The airfoil is a 'so high - but a little longer with a curve on the top but not so much on the bottom' or a scratch drawn semi-symmetrical.

Most of the plane is expanded polystyrene beads (later referred to as foam) but a few pieces of wood, wire, or fiberglass are put in for strength only where needed. The nose section is the only part that doesn't use a template for cutting. In other words, cut off everything that doesn't look like a Lear Jet, using the top and side views from the plans.

I hope, even if your 'bag' isn't the Lear, that my technique of cutting foam might spark your imagination for a creation of your own. One last word before we start, no putty and very little paint to keep it light.

If your hot cutter is too short or your blocks too short for a one piece fuselage, it can be cut in three separate sections: nose, center (with wing saddle), and tail cone, and glued together.

Fuselage: Start with 7 in square block 48 in long. Secure the wing saddle template so that the leading edge of the wing is 25 in from the nose (Photo 1). Support a hot wire 2- high across your table. Lay the block across the wire at the leading edge of the wing saddle. Afterthe weight of the block has cut the leading edge, pull the block forward cutting the top of the wing saddle (Photo 2) until you reach the trailing edge. Lifting the block will complete the wing saddle cut. Mark center lines, vertical and horizontal. at both ends and attach templates Fl and F2 to the ends (Photo 3).

Skewer block between two nails at the center lines so that the block can be rotated (Photo 4). Nails can be taped between wall and chair, wall and desk, desk and chair, etc. Starting with the bottom side up, lay hot wire on the templates and rotate the block making a 7 in diameter cylinder (Photo 5). Before removing the cylinder from the block, mark the top view and the side view of the nose section, respectively, on the block and cut (Photos 6 and 7). Lightly mark the top and bottom center line from the nose to the tail to keep the wing pins and tail fins better aligned.

Attach templates F3 above and tangent to the center line of the tail end of the cylinder (Photo 8). One layer of masking tape under a piece of soft wire 19 in from the tail end keeps the wire from marking up the fuselage while cutting the tail cone (Photo 8)..."

Update 06/03/2017: added article, thanks to RFJ.

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