Lucifer (oz6197)

About this Plan

Lucifer. Bob Amor's 75in wingspan A2 glider from Aeromodeller January 1957.

Quote: "Build Bob Amor's World Championship class A/2 that placed 2nd in Florence. Lucifer.

BOB AMOR'S IDEA of the ideal A/2 layout is Geof Lefever's Altair (oz10331) described in our September 1955 issue. Geof and Bob, by the way, are aeromodelling pals so it is quite natural that 'Lucifer' follows the design trend of the now famous Altair.

The idea was to retain the good towing characteristics and reliable performance and at the same time improve the actual sinking speed of the model. To do this, fuselage size was reduced to an absolute minimum and as smooth an entry as possible was obtained. The thin Benedek 6356b section was employed on the wing and the chord increased to make it more efficient.

Final result is a model which does in fact go up on the line very well, providing it is not towed too slowly to start with, and the sinking speed is about the best of any model Bob has made so far. Normal trim is a fairly tight left circle, this of course, is essential for competition in windy weather, for the purpose of remaining in sight.

At the World Championships in Florence, the air was very hot and dry and almost dead calm. The only alteration to the trim was to open the circle progressively on two or three test flights previous to the contest, until the model was just trimming off the stall and executing about 100 ft diameter circles. Thermals were weak and patchy, but the model made the most of what lift there was.

Trimming should present no difficulty to any experienced modeller, providing the wing incidence, centre of gravity and tow hook position are correct. If any warps develop when the structure is doped, these should be carefully removed before attempting to test fly. Make gradual adjustments to the auto rudder as it is quite sensitive on the turn trim.

Construction: The wings are straightforward except for the joining dowels. Paper tubes are wound on the dowels and then cut in half although left in position. After the leading edges of the wings have been sheeted they are put together on the building board and the remainder of the top wing sheeting added all in one piece. The wing is then turned over as a whole and the ribs are cut into from the underside and the paper tubes with the dowels inside are firmly cemented into position. The sheeting to the underside is added and when completely dry, the two wings are parted by cutting through the sheet. A strip of two-inch wide bandage is cemented round each wing root before covering to strengthen up the whole assembly. The tailplane and fin should be made as light as possible.

Fuselage construction is very simple, but the sheet for the boom should he carefully selected for strength without being too heavy and care must be taken to get the boom absolutely straight. The lead ballast should be cast in a box made of scrap balsa, and when the box has been removed, make it a force fit in the plywood keel.

Cover the model in lightweight Modelspan and dope with glider dope, two coats for the tailplane and fin. Finish the fuselage with repeated coats of thin coloured dope, sanding between each one until a high gloss finish is obtained."

Direct submission to Outerzone.

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