English Electric Lightning (oz9707)

About this Plan

EE Lightning. Free flight semi-scale model for IC ducted fan with .049 power.

Quote: "IF THERE IS one type of aircraft that is guaranteed to create interest on the flying field, then that is the ducted fan model. There was a great deal of interest in this form of power many years ago, when Veron introduced the famous Lavochkin LA-17 (oz598) and Sabre free-flight kits for small engines, and these kits even included an aluminium impeller. Although these models were very successful in the hands of experienced modellers and built up into really fine models, for the inexperienced or junior modeller success tended to be marginal.

There has been a lot of development since those early days, mainly in regards to the fan and there is now a range of five fans produced by Veron to suit almost any engine, while the range of small easy starting glow engines that produce little vibration seem to be unlimited.

With this in mind, my interest in ducted fan models was rekindled and in 1966 I designed and constructed a small model that resembled the English Electric Lightning. With a wingspan of 18 in and powered by a Cox TD 049 engine driving a Veron Type B impeller cut down to 2-1/2 in diameter, the model tipped the scales at 7-1/2 oz. Owing to the very small impeller blades the engine used to turn over at about 25,000 rpm. Quite a head turner, this model made many spectacular flights, but owing to insufficient fuel proofing of the duct it became heavier and heavier, till at last it was too heavy!

Various models were built after this, ranging from a small Cox Pee-Wee powered model to a large (36in span) model powered by a PAW 2.49 driving a Veron impeller and equipped with an Otarion single channel receiver and a Fred Rising escapement to operate the rudder. Unfortunately, due to terrific vibration, could not prevent the actuator from skipping (owing to my own lack of experience at that time), and the model subsequently made many flights free-flight, until one day it disappeared into the blue after filling the 4 oz R/C tank to the brim! It was recovered two months later about five miles away.

After that episode I built the first of the present series that was destined to resemble the Lightning, using a Cox Baby Bee engine owing to its compactness in having the tank and engine mount in one. The resulting model weighed 8-1/2 oz and spanned 23 in, the only trimming required proving to be a small amount of weight added to the nose and a small vane in the tailpipe to give downthrust effect. This model was flown regularly for about 18 months and it is estimated to have made about 400 flights.

Model No.2 was constructed after this and incorporated a few modifications -mainly an increase in fuselage length and cross section and improved appearance (as the previous model was given the name Flying Drainpipe by fellow modellers owing to its short cylindrical fuselage). A beam mounted Tee Dee 051 engine driving a Veron type impeller was fitted with a small team race fuel tank. A small cone was fitted behind the engine to smooth the air flow, and behind the fan eight flow straighteners were added.

Again, this model required very little trimming and it was soon apparent that the Cox TD 051 engine was producing more thrust than the Baby Bee. It had a much better climb and indeed it would climb in left hand circles till it was a mere speck in the sky, followed by a glide to the right. This model made about 40-50 flights until one Sunday afternoon it flew OOS and was never recovered.

In June last year I completed the Mk III - the model drawn here - powered by the old faithfull Cox Baby Bee and incorporating all the design features of the MkI and MkII. It is a joy to watch in the air as it does not drag its tail in flight and has a surprisingly flat glide..."

EE Lightning, Aeromodeller, February 1972.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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