Thermal Hopper (oz8909)

About this Plan

Thermal Hopper. Radio controlled FAI sailplane.

Quote: "A spoiler equipped super floater from Old England. It hand-tows aloft to hunt for lift, a servo actuated lock on the hook. 6th at the 1971 International Soaring Competition at Doylestown, Pa. Hard to find a fault with it! Thermal Hopper, by Geoff Dallimer.

During the 1971 R/C World Championship meeting at Doylestown, USA, your editor Don McGovern asked me if I would do a feature article on the R/C Thermal Soarer I was flying in the contest. Little did I imagine that I would be writing by the light of two home made oil lamps! Indeed it is in quite a 'Pickwickian' atmosphere that I am writing, and one could well be in the 17th century England, instead of the 20th. Not 200 yards from where I sit, stands an old coachhouse inn reputed to have an underground passage used by the celebrated highwayman Dick Turpin, well known by ill-repute! This particular inn is known as the 'Roebuck' and lies just south of Stevenage on the Roman Great North Road.

Of course little of the above has any connection with Thermal Soaring - except perhaps the heat from the oil lamps! The reminiscence is brought about by Great Britain being hit by a nationwide electricity crisis due to industrial problems - hence the need for oil lamps! However perhaps my model does have something of an English flavour since the building methods I use are simple and indeed the construction is very similar to A/2 models I built a decade ago. Nevertheless, considerable development has gone into the model beneath its modest tissue covering, and Thermal Hopper is a well bred competition model.

I first started building R/C thermal soarers some four years back, and after a year of experimentation, started a series of thermal models. First design was Thermal Rider (oz9698) of 8 foot span and was published during 1969. The design was scaled up to 12 foot span for the second model in the series known as Thermal Hunter, but I have settled back to a 10 foot span for the current model. This is considered to be an optimum size of model for competitive fly-ing. Larger models may appear more efficient but become unmanageable on the ground in windy weather. Here in Great Britain conditions are usually breezy if not always windy. Thermals appear to be smaller in area and less strong than those we found during our short stay in Pennsylvania, and certainly not like those we read about in California and Texas!

When the possibility of coming across to fly in the USA first arose, my colleague Dave Dyer and myself spent some time wondering what sort of weather to expect, since having a model to suit the conditions is of prime importance in thermal soaring..."

Thermal Hopper, Flying Models, June 1972.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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