PeanutScale.com [This article was published in the December 1971 issue of The Model Builder magazine.]
Peanut Scale Laird LC-DC
By Walt Mooney
Peanut scale of a little known biplane from the Giant’s Hangar of the Golden Age of Air Racing. Long nose moment of the Laird LC-DC makes it an easy plane to balance, gives long motor run.
This is an extremely pretty little biplane racer. Its configuration is particularly suitable for a rubber powered scale model. The long nose and the long tail length make for an easily balanced and stable flyer. Three models of the Laird LC-DC were built and they have all proven to be nice flyers. All three models are capable of flights of more than 30 seconds.
The model construction is strictly conventional. As drawn it will not result in a particularly light weight Peanut Scale model. However, careful attention to wood weights and the use of slightly smaller wood sizes will result in an indoor type model capable of even better flight durations.
The real airplane had a lot of stringers fairing out the fuselage. These are indicated as dash-dot-dash lines on the drawings. Omission of one or more of the side stringers in the interest of simplifying the model will hurt the overall appearance very little unless you worry about the last scale point in a contest. Flight wires can also be omitted in the interest of simplicity and less flight drag if desired.
For those who are interested in scale details and the utmost in judging points, good three-views of this airplane and other interesting racers are available from R.S. Hirsh, 8439 Dale Street, Buena Park, Calif. 90620.
The model should balance about an eighth of an inch aft of the lower wing leading edge. No downthrust was required on the models built and the maximum up elevator adjustment was used.
Since the model structure is strictly conventional; a box fuselage with formers and stringers, single spar wings, and sheet balsa surface tip outlines, only a few specific comments will be made.
First, the wheel diameter is rather large for a Peanut Scale so it is important to keep them light weight. Make them out of balsa or better yet mold them on a Vacu-form over a balsa or hardwood form.
Second, the struts for the wing and landing gear will take quite a beating so the must be strong and light. Make them from very hard one thirty-second sheet, or if it’s available at your hobby shop, cut them out of one sixty-fourth plywood. (This very thin ply is available from “Sig”.)
Third, the plastic propellers work well, but for even better flight times, a carved wooden propeller with wider blades will give longer durations.
Fourth, all cowling details shown, and there are many more shown on Mr. Hirsh’s three views, are made from balsa scraps or whatever else is suitable from the scrap box.
Fifth, cover the model with light weight tissue. Shrink it with a fog of water and when dry dope the wings and tail with one coat and the fuselage with two coats of thin dope. Use tissue for color trim and numerals, and felt pen for coloring the struts and wheels. A light coat of dope will fix the felt pen coloration so it won’t run if your model lands in the dew.
Sixth, a single loop of three-sixteenth flat rubber about ten or twelve inches long is the right power for the model as shown. Wind it with an indoor winder after lubing it with rubber lube. Have a helper hold your model while you stretch the motor out at least three feet at the start of winding. As you put in the turns gradually let the motor decrease in length until the noseblock is in its proper place as you finish winding. For a beginner in rubber scale modeling, this technique of stretching the motor will allow many more turns to be wound into the motor and give much longer flights than simple hand winding of the propeller with the noseblock in place on the front of the fuselage.
Seventh, there should be no warps or twists in any of the flying surfaces. With this type of wing strut, a warp is hard to remove after the struts are installed, so carefully check the wings before installing the struts.
We’ve had a lot of fun with our Lairds, happy flying with yours.