Fifi (oz16791)

About this Plan

Fifi. Rubber competition model. Coupe d'Hiver class. Wingspan 51.8 in.

Quote: "Fifi la Coupe. John Barker's sparkling Coupe rubber model is the latest in our free flight contest designs.

Fifi is as she is, because of her ancestry. For instance, an early forebear had a single fin but this was always in the way when working on the tailplane and, if fixed to the fuselage, transport was awkward. So, what to do? I have long believed that twin fins fly better, and when I realised that I need only remove one to allow the tailplanes to stack in a corner of the model box, the fate of the single fin was sealed.

More significant was the change to two-piece wings, introduced to make retrieval easier, (particularly in bad weather), to ensure the wings were correctly fitted without keys, and to avoid the damage caused by rubber bands.

Plug-in wings have proved to be far more damage-proof than those banded-on due to the flexibility of the wire joiner. Fifi uses just one size of rubber band - which saves lots of trouble when getting dressed. There are D/T bands, two to retain the tailplane, one across the centre section, one in each control line - and one at each end of the motor.

The two-piece feature partly led to the tapered planform although there were other structural benefits. When I wanted to thin the section and increase the span, I needed room for the joiner - which the bigger root chord of the taper wing provided. The fact that it seemed aerodynamically better was a bonus.

The timer is where it is so that I can release it as I throw the model. Although I make my own timers, Free Flight Supplies can supply multi-function Tomys mounted on a faceplate at a reasonable price. Lines from the timer are carried inside the fuselage to prevent snagging.

A square fuselage is unusual nowadays: I tell people that I can't stand the drag of a round one and, to a large extent, this is true. Where would I put the timer and tracker and how could I make such a clean wing joint?

Another reason is that I make what I fly, and I haven't yet developed a moulded fuselage. The structure shown on the plan was devised to stiffen the thin material by mating a straight-grain edge on one triangle, with an end-grain edge on the next. It does the job, but will be a new approach for most builders. If you want a conventional build, 3/32 sq longerons with spacers: it is familiar and light, but not so good in wet weather and it is more difficult to round at the nose..."

Fifi from Aviation Modeller International, April 1999.

Direct submission to Outerzone.

Update 4/6/2026: Added missing page in the article, thanks to RFJ.

Supplementary file notes

Article pages, thanks to RFJ.

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