Lee Richards Annular Monoplane (oz15099)

About this Plan

Lee Richards Annular Monoplane No 3. Radio control scale model. Wingspan 33 in, for 19 to 25 engines.

Quote: "Lee Richards Annular Monoplane. Designed by David Boddington. Built by Frank Palmer.

According to statistics around 80% of all aeromodellers are R/C orientated. It would be reasonable to expect a fair proportion of 'dodgers and wheezers' (the descriptive names given to the British experimenters and inventors of WW2) within their ranks. Regrettably this is not true and the number of R/C enthusiasts prepared to put their hands to something out of the ordinary is very small indeed. Can they all be satisfied with flying their 'Super 60s' and 'Wot 4s' around all the time?

If it's inspiration and original designs you're looking for you would be better off scanning the pages of our sister magazine 'Aeromodeller'. Every issue is almost bound to have some unique design or piece of lateral aeromodelling thinking. Maybe the inventive items are related to free flight, control line or indoor models, but they are the results of fertile minds and help to advance aeromodelling generally. What a shame the R/C modellers do not make greater use of the radios, engines and materials available to them.

One issue of Aeromodeller had a delightful little design for a rubber powered Lee-Richards 'Flying Doughnut' (designed by Richard Halfpenny) and this was sufficient impetus to get the pencil sharpened and the Tee square moving up and down the drawing board. Designing the model made one realise how very advanced were these pre-WW1 prototype aircraft, not only for the wing planform but for the telescopic tricycle undercarriage and wind driven generator. Far from being the 'string and sealing wax' contraptions imagined by many of the public, the circular wing aircraft had been very well researched and developed.

It is one thing to know that the full-size aircraft flew - albeit with two of them crashing, and the small rubber powered model was a stable performer - but the doubts about the wisdom of tackling such an unusual subject increase as the design takes shape. Being, as usual, involved on numerous projects at one time I was keen to find a fellow modeller who would be prepared to have a go at an 'unknown' project. Remembering Frank Palmer's obvious modelling skills, from seeing his models at Primrose Valley, I knew that he would be more than capable of translating the drawings into three dimensions. Frank is one of the old school of modellers, with a gift of understanding, interpretation and adaption.

Because of the pioneering aspect of the design there was no intention of producing a class one scale model, it would be accurate in outline but not feature scale detail or rigging. Once the design was proven other builders could add the gilt to the gingerbread - or doughnut!

Read the Prototype Parade articles and study the drawings carefully before commencing the building as this will give you a feel for the subject and get you into contemplating some of the more unusual aspects of this unusual design.

January is not the ideal month to contemplate test flying any model and particularly not an 'iffy' prototype. However, the weather forcasters promised a fine windless day for the Sunday, so I arranged to meet Frank at Goosedale Museum at Noon. The met-men almost got it right, there wasn't too much wind and no sun. The model was ready rigged (the circular shape will allow it to fit, in flying condition, in most car boots) and it was only necessary to give it a quick once-over, carry out a range check and prepare for flight. There was no point in re-checking the balance point as this was an unknown factor, it obviously had to be somewhere ahead of the main wheels and behind the engine! I could find no guide to the actual C of G of the prototypes, or rubber powered model, from the various published articles.

Frank had connected the tail surfaces to act as rudder control and elevators, ie no aileron authority. I had envisaged using the 'elevators' as elevons and was not too sure whether the circular planform and minimal dihedral would allow good rudder turns. As later stated, the Irvine 20 had to be fitted with a home produced exhaust manifold and this resulted in a tortuous double 900 exhaust gas flow into the standard silencer chamber. Considerable back pressure would undoubtedly result, but would the engine continue to run?

No more prevarication, time for action. The engine started sweetly, Frank released the Polo without the mint and away she went tracking absolutely straight and true. Speed built up and there were no signs of her leaping into the air, a gentle back pressure on the elevator stick and a clean lift off was followed by a steady climb out. She flies! It was one of those times when it is difficult to know who is the most surprised, the spectators (my God, what's that?) the builder (Frank had a sleepless night) or the designer (for having the temerity to commit compasses to paper). A right hand circuit to gain height, a little up trim and there she was, flying hands off.

Two worries were soon dispelled, the model turned well with only rudder control, no adverse yawing and no wing dropping. Also, at normal speeds there is no 'Dutch rolling' (probably because of the small dihedral angle) as the model slows up for landing it is simply a matter of not over controlling.

One of my assessments of a test flight is whether I dare to fly the model slowly enough and close enough for in-flight photographs to be taken. Although the Lee-Richards Annular was not on my normal transmitter mode I had no hesitation in carrying out low fly pasts for the camera. The model has the flying qualities of a good sports model, but the slow flying abilities are better than average. By good fortune we had got the balance point and control surface movements right first time. On the second flight I looped and rolled the model, not because these are manoeuvres you would normally undertake with this type of scale model, but to explore the flight envelope. Stalling is highly predictable, you have to bring the nose really high (no doubt the slot effect contributes to the low stalling speed) and when the stall occurs the nose drops away until speed is built up and the model then recovers to an even keel and is flying again with a minimum height loss.

I have no qualms in saying that any modeller capable of flying a high wing three function trainer proficiently would have no problems in handling a 'doughnut'. The Irvine 20 provided more than adequate power for the model, even though she did tend to load up a bit on the second flight. Why not put some adventure into your scale modelling, build an annular and try it with elevons, as with the prototypes. We've done the hard work for you, now go ahead and make a detailed scale model of this truly different flying machine... "

Direct submission to Outerzone.

Annular Monoplane from R/C Scale Aircraft April 1993.

Supplementary file notes

Article pages, thanks to RFJ.

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