Thermaleer (oz10523)

About this Plan

Thermaleer. Lightweight rubber competition model.

Quote: "A 36 inch span lightweight rubber job. Thermaleer by BT Faulkner.

ECONOMY, structural simplicity, and consistency are features of this 36 inch lightweight, which for a number of years has been the Cheadle MAS standard rubber design. Originally developed from a 20 in span indoor F/F which featured geodetic wings and incidentally gained the designer his 'A' certificate flown outdoors, the present layout was developed through 30 in and 36 in models to the plan presented here.

Folding props have been rejected as being inconsistent; stall recovery with this model is superb - this can be attributed to the free-wheeling prop which wafts the Thermaleer up to 350 ft. Normally a flight of 3-1/2 min should be expected using 10 strands of 36 in Pirelli, but substitution of 8 strands of 50 in will increase the motor run to 21 min. giving a still air time of something around 4 min. With this motor, a smaller prop of t4 in. is recommended to provide the desired climb, and incidentally, smooth out the glide to a rate of descent which approaches that of a folder. However, this prop/power combination is not recommended to beginners since it involves a special winding technique to prevent bunching at the tail.

The original Thermaleer placed second in the club champs in October 1951, with 8:51, third at the NWA Winter Rally 1952, with 3:33 and 3:15 in appalling weather, and first at the Butlin's Pwllheli contest in June 1952, where it was lost into the sea. Garth Evans won the September 1952 Butlin's meeting with two maxs from his modified Thermaleer, again losing the job - this time into a forest. Before this, the model came sixth in the MA Trophy (Nats, 1952). A modified version of this layout by Andy Anderton, the Marathon, which uses an eight strand motor has gained a number of successes, amongst them 3rd at Woodford 1952 and 2nd at Woodford 1953, apart from several RAF comps., and others too numerous to mention.

Construction should present little difficulty, though the selection of wood is very important, of course. Strip should be medium/hard straight grained for longerons and medium/soft for spacers; medium/soft LE, hard mainspar and medium TE. All wood should be dead straight. When building the wing, care should be taken to make all parts fit easily, thus preventing a strained framework. Build 1/16 washout into the left outboard panel; all other-parts of the wing dead flat. This applies to the tail-plane, which should be flat. The Garami free wheel is worthy of note - this prevents a motor blow-up if the prop free-wheels under power due to a bunch..."

Thermaleer, Model Aircraft, September 1954.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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