Opus (oz8471)

About this Plan

Opus. Sports free flight delta for 1 - 1.5cc engines.

Quote: "CONSTRUCTED as number four in a series of free flight delta-style sport models, Opus was made during 1964. Previous models showed a single dorsal fin to be satisfactory under power, but ineffective during the glide - the model gliding away at high speed in whatever direction it happened to be heading at the time the engine stopped!

To cure this situation, Opus was given a long ventral fin to overcome the power-to-glide transition problem. Although it was thought the ventral fin would be rather vulnerable in this position it has withstood some very hard landings and achieved its objective in giving directional stability, even if it makes the model resemble a paper dart in the air.

The centre of gravity can be varied over a large range of movement with little effect on flight providing the elevator is also trimmed to suit. The balance point shown on the plan should give everyone satisfactory results, and different positions can be tried for experiment once flying experience has been logged.

With an AM15, Opus may seem a little underpowered to some enthusiasts, but due to its fast glide characteristics it would seem unwise to increase the speed any more. The original Opus terminated its lease of life in a high speed argument with a equally high tension electricity cable, but in general its shape allows it to survive most collisions.

Commence construction by laying wing/fuselage 1/8 x 3 in centre sheet over the plan cutting slots for fin, and cutting out for engine bearers. Then pin down 1/8 x 3/4 wing edges, (not the elevator trailing edge). Note that one half of the plan only shows internal structure..."

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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