This article has been reproduced from the December 1960 edition of Mechanix Illustrated and authored by Paul Del Gatto.

 ELECRO-MITE             

 Now hear this!  Here is a model plane whose motor will always start in a split second.  No priming, fussing or spinning.  It's electric.

By Paul Del Gatto

While electric power for model airplanes hasn't been ushered in with the pomp that accompanied practical gas engines in the early 30's, it is at least equally important.  The electric motor is undoubtedly the simplest and most economical power for all types of models.  It also gets rid of the big bugaboo that has stifled model flying in many areas: noise.  Already, civic organizations which have curtailed all types of flying are seriously considering the dropping of some barriers.

We've been experimenting with electric-powered control-line models for over a year now and the results have improved with each endeavor.  In Electro-Mite, the delivered motor power is substantial enough to permit rapid take-off and climb and many simple maneuvers, including perfect loops.  The model differs somewhat from the average control-line model in that it has a single-surface cambered wing and a built-up fuselage profile.  It is patterned after a typical World War II Navy dive bomber.

Before starting construction it is necessary to enlarge the fuselage plan.  Then cut two profiles of the enlarged fuselage out of 1/32-inch sheet balsa.  Using the plan as a guide, cement the required 1/8-inch square longerons and cross braces to one side and install the 1/8x1/4-inch landing gear support and all the 1/8-9nch sheet balsa fillers.  Apply cement to all the members and then press the remaining fuselage side into place.  The landing gear strut is bent as indicated on the plan and pushed through the fuselage profile at the indicated point.  It is then bound with thread and cemented.

Select a smooth but pliable piece of sheet balsa for the wing and cut the two halves to the required shape.  Then cut out the ribs and cement them to the bottom of each half, using straight pins to hold the curve until the cement dries.  When the cement is dry, bevel the edges of the center ribs to the angle required for a flush jont at the proper dihedral.  Then the wing can be cemented in the fuselage cutout.

The tail surfaces are cut from 1/16-inch sheet balsa.  Since the model is quit light and can fly with little or no control, it has only one movable elevator.  Nylon thread hinges looped around the surfaces only once are more than ample.  The elevator control horn and the wing lead-out guides are bent from copper lugs and cemented in place.  When the horizontal tail assembly is complete, it is cemented in its slot.  The fin and rudder follow, with the rudder offset a quarter-inch to the right.

Hard 1/8-inch sheet balsa is cemented in place for the bellcrank base.  Then the bellcrank is installed.  Use a nylon or plastic bellcrank; metal is not recommended, though many composition materials or 1/16-inch plywood may be sustituted.

For best performance, we strongly recommend a hand carved propeller made to the specifications shown on the drawing.  Select very hard balsa or soft pine and make a pencil layout right on the blank.  Then remove the shaded areas A, B and C in that order.  When this is done, all that remains is to carve the propeller twist as indicated by the blade section shown on the end of the block.  Remember that the twists have to be opposite to each other as the cut of any commercial propeller will make clear.  The blades should be thin right up to the hub and rounded off at the ends.

The hardwood control handle is easily made as shown.  The use of a slide switch permits the flyer to shut off the power instantly if the model ever looks as if it's heading for trouble.  The handle is finished by brushing on at least one coat of clear dope and a following coat of paint.

Navy colors of dark blue and gray were used on our model.  The colored dope is thinned down and two coats are brushed on.  Keep the paint coat light because any added weight will take away from flight performance.  The required decals can be purchased at most hobby shops.

Install the motor by wedging it between the two balsa blocks.  Then shape and install the wire pushrod and hook up the controls.  The insulated wire leads are hooked up from the motor to the bellcrank and passed through the lead-out guides.  At the end of each lead, a lug is soldered to permit rapid hook-up for flying.

Flying is a lot easier than with the conventional control-line model.  All you do is reel out the leads, hook them to the lead-out wires from the batteries and flip the switch to check the propeller rotation.  If the propeller goes in reverse, the leads are reversed and should be switched.  Do not attempt flying in real gusty wind.  Pick a fairly calm day and try a take-off from reasonably smooth ground.  Beyond that there is no problem, except to flip the switch for flying and flip it off to let the model down.

BILL OF MATERIALS

HARD BALSA

 One piece                     1/32"x3"x36"                 Fuselage profile and farrings                                                                One piece                     3/32"x3/16"x36"             Wing ribs

MEDIUM BALSA

One piece                         1/16"x4"x36"                Wing and tail surfaces                                                                    Two pieces                        1/8"x1/8"x36"               Fuselage members

WIRE

One piece                            27"x0.049" diam.          Landing gear and pushrod

MOTOR

One T-03 electric motor (1:15 ratio): Made in West Germany and available from Micro-Mo Electronics, 3378 East Bvld., Cleavland 4 Ohio.

MISCELLANEOUS

Nylon thread hinges; 1/8" sheet fill-in balsa; 1" diam. wheels; washers; nut and bolt; 3/8"x1"x9" hard balsa or pine propeller block; setscrew; decals; No. 30 insulated copper wire leads; Nylon or plastic bellcrank; cement; clear and colored dope; hardwood handle block; C or D batteries; slide switch; bell wire; small screws.

Back to articles

© Pacific Aeromodellers Club
Powered by Wild Apricot. Try our all-in-one platform for easy membership management