Electra (oz6614)

About this Plan

Electra. Radio control sport trainer for 2 or 3 channel radio and .05 electric brushed motor. Discontinued kit from Carl Goldberg.

Quote: "Electra is a state of the art thoroughbred with the temperament of a pussycat. She is based on the proven and popular Gentle Lady (oz2359) sport sailplane redesigned for the higher performance demands of electric flying..."

Update 24/04/2018: Added kit review from Flying Models, October 1987, thanks to RFJ.

Quote: "FM Product Review: Carl Goldberg's Electra, by Dick Gibbs.

Perhaps, like me, you have been thinking about trying electric flight but never really got serious about it because electric flight seemed just a bit mysterious. Perhaps, like me, in reading published material about electrics you have discovered that:

1. Electric flight is fun.
2. You must build light or your electric won't fly.
3. It may (or may not) take forever to find the right combination of battery/motorfprop to successfully fly your model.
4. It may (or may not) be to your advantage to have a graduate Electrical Engineer as your flying buddy.
5. Charging your flight system is (or is not) an arcane process during which you will (or will not) fry your battery - and your radio.

Or perhaps, like me, you will build an Electra and discover that the folks at Carl Goldberg Models have taken the mystery out of electric flight! The Electra, somewhat similar in appearance to the popular Goldberg Gentle Lady, is an electrically powered glider with a wingspan of 78-1/4 inches, 41 inches long, and has a design weight of 48 ounces. At that weight the wing loading is about 10-1/2 ounces per square foot which means that thermal soaring is certainly possible.

The kit is available as a standard kit (No. K-41), which is the model only, at the suggested retail price of $44.99, or the Deluxe version (No. K-40) which is the standard kit plus a Turbo 550 (Mabuchi) 05 size direct drive electric motor with an attached wiring harness which includes a 20 amp fuse, on-off toggle switch, and Tamiya connector.

Also part of the Deluxe package is a 1-3/4 inch Goldberg snap-on spinner, prop adapter (for mounting the propeller on the motor shaft), an 8-4 nylon prop, and a plastic motor mount. Retail price of the Deluxe Electra kit is $59.99. The suggested motor battery (not furnished with the kit) is the Tamiya six cell (1200 mAh) 7.2 volt Ni-Cd pack which is widely used in RC electric cars. An alternate power source is the seven cell (8.4 volt) hump type pack. Either two or three channels are required of the radio system depending upon which type of motor control you intend to use.

The kit: Balsa and plywood in my kit were of good quality with very accurate die-cutting for the wing ribs, fuselage pieces, and bulkheads. Wing leading and trailing edges are pre-shaped and trailing edges are notched to accept the ribs. The hardware package contains control horns, hinges, devises, control rod exit guide, all necessary nuts, bolts, wood screws, and wing hold-down dowels. A nicely formed canopy, plastic cowling, and water transfer decals are part of the kit. Everything required to build the model itself is here except adhesives and covering material.

One large plan sheet has all components drawn full size and both wing panels are shown. Side and top fuselage views indicate suggested radio placement as well as direct and geared electric motor installations. The plans are well drawn, accurate, easily understood, and contain many building notes. In addition there is a 32 page building manual which is a thorough step-by-step instruction guide, well illustrated with clear photographs and line drawings. Beyond building suggestions, the manual offers good tips on covering, radio installation, and even a short course on R/C flying. A very professional job directed to the newcomer to R/C or even the person for whom this is the first attempt at model building. Very impressive.

Construction: At first glance the building manual may make the Electra appear a complicated piece of work but everything falls readily into place if the construction sequence is followed literally "by the book". Fin, rudder, and stabilizer are built on the plans and come up as light, strong structures. The four wing panels are joined with ply dihedral braces and it's almost impossible to mess up the three joints because simple die-cut ply dihedral jigs, furnished in the kit, do the job without the necessity for measurements on the part of the builder. When the wing spars are glued together the parts are held tightly with die-cut clamps. 1/16 sheet balsa is used for covering the leading edge portion of the wing and the center section.

When completed the wing is quite sturdy and made even stronger with nylon tape glued to the sheet balsa joints at the dihedral breaks. Full instructions are given for building the wing in one piece or with detachable tip panels. If the wing is built in three pieces the largest section is 41 inches long, suitable for transportation in even the smallest of cars.

The fuselage builds up fast with die-cut sheet balsa sides, top, and bottom pieces. Here again the illustrated manual makes this an easy task. Quarter inch square balsa strips and threaded rod are used to make up push rods for the rudder and elevator. Working during the evenings it took me about a week to frame up all components, finish sand the entire model, make up push rods, and trial fit the radio and motor systems. Before covering, the bare bones were weighed, with the fuselage at 4 ounces, tail assembly 1-1/4 ounces, and wing 8-3/4 ounces for a total of 14 ounces. Goldberg Jet and Super Jet cyanocrylate adhesives were used throughout and the gluing process was made even faster by using Jet Set for instant bonds... "

Update 28/04/2018: Added kit review from RCM&E, June 1991, thanks to RFJ.

Update 22/5/2024: Added kit review from Model Builder, September 1987, thanks to RFJ.

Supplementary file notes

Decals.
Instructions, 32 pages.
Parts ID sheet (could be scaled up for wing ribs?).
Reviews.

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