1970 JOHN POTTER
Flight Lieutenant John Potter MA RAF had contacted the Royal Aeronautical Society asking about HPF and learnt of the plight of Jupiter. A plane without a group. Well, actually the plane was in almost as bad a state as the group. He arranged to meet Sir Stuart and myself at Woodford, Essex to see the hardware. Number one, chronologically, in the actions for which he deserves special credit is having the imagination to see a heap of rubble and think `I am going to transform that into an aeroplane'. As I saw it then, my options were to allow this man to turn it into a static exhibit at best, or to let it carry on rotting; so I chose the former.
MY FEELINGS (with hindsight ) about the HANDOVER
Jupiter was to become the only HPA which performed better after being handed over to new leadership. Is this a point for me to be proud of ? Yes, insofar as John could generally follow drawings originally prepared only for myself. Yes, insofar as it meant that as mentioned above, Jupiter became in some ways the first non-experimental HPA. No, since if the mistakes I made had been different ones, the original group could have seen the project through. I had built the fuselage big enough for my 6ft 2inch (1.88 m) self, but realised that others have more flying skill. While being sole leader of the project, my intention had been that when it came to flying, that at the moment of take-off the pilot would become the boss. Thus you are flying your aeroplane. It is one system, maybe not the best, but the decision on my part to adopt this policy had partially prepared me for relinquishing control.
On arrival at Halton John and I dumped all the components in the canoe-club shed. The task of convincing others that here there was a worthwhile project began. Sir Stuart Mallinson wrote to Air Commodore Weighill, the commanding officer at Halton. `When Flight Lieutenant John Potter came here, he took away what was left over from a fire of an aeroplane built by Hodgess Roper. ... worked in two of my garages building what he hoped ... Unfortunately, after 5 1/2 years he had an accident which prevented him for over a year doing anything, and after some 6 1/2 to 7 years a fire broke out and destroyed part of the machine. It is quite impossible for him in his condition to carry on or replace, and eventually he apparently arranged for it to be taken over to your Base. I think there is no question that Hodgess Roper had a good idea and there was a reasonable prospect that he might have been successful. .. I hope it may be possible for you to encourage the finishing of this machine. ` Stuart Mallinson'
SUPPORT from ROYAL AIR FORCE
In much the same way as at Woodford,Essex, the plane was moved step by step into better premises. At one time it occupied the only room at Halton College which had access without going around twisting corridors. This was necessary because of the length of the wings. Other staff, Mrs Potter, and the more senior apprentices became interested, joined the Halton group and helped with the repair and later with the flying operations.
John's policy was that if anyone turned up, then he would find them something to do. I took a friend with me to Halton on one occasion and they were promptly given the task of making sanding blocks. In this way, if a person persisted they could then proceed to other tasks, if they didn't, then at least they had done something. As the group built up, he was able to delegate entire components, and 3/4 of the work of restoration was done in 20 weeks. (Potter 1973)
As far as I was concerned, from now on, Jupiter was nothing to do with me. But this situation did not last very long. John was working to the detail-working-drawings that I had prepared at Woodford, Essex for my own use, and they were such that he was able to do this. Well, there was an exception to this. On one drawing, I had written .028" x 1/4" which taken literally indicates a strip 0.7mm x 6 mm and John quite rightly didn`t believe that this was what I intended. So he phoned me. I replied that this meant a tube 1/4" diameter and .028 thickness; a stocked size. Being asked to resolve this ambiguity was all it took to re-awaken my interest in the project. I visited Halton from time to time. I made a few new drawings or new copies of old ones.
The original tailplane and elevator needed replacing, and I took the opportunity of a redesign here, in consultation with John. The new surface was all-moving, had a higher aspect-ratio and was positioned slightly further aft. This component was built at Woodford, Essex in 1971. The original control linkage was retained. Unfortunately this led to flying problems, a small movement at the control bar having too much effect. I had made outrigger wheels and fitted these just inboard of the ailerons. John decided to dispense with these and they were not used in flight. I feel that this was probably the right decision. The Puffin I outriggers had been removed after early flights. However on Toucan, outriggers at 40% of the semi-span had proved satisfactory. The Halton group finalised the detail design of the aileron control linkage, and made and fitted these parts Much of the trailing edge had warped because of damp storage. This would increase induced drag because the lift distribution would be affected. Looking at it another way, in flight each warp would create its own little additional trailing vortex. So, a lot of the trailing edge was cut away and replaced. The outer wing sections were found to be in good condition and were left with the original blue Melinex covering which Susan and I had put on at Woodford, Essex. The other three sections needed various repairs and were then covered in John's choice of aluminised Melinex.
FUSELAGE TORSIONAL STIFFNESS
When the plane was nearly assembled, I noticed that it was very easy to move the top of the fin from side to side because the rear-fuselage is easily twistable. This didn't seem right, but apparently didn't matter, being less critical than wing torsional stiffness. Ironically, it was partly because of the observed low torsional stiffness of the tail-boom that I had rejected it.
Halton is a grass airfield. When the aeroplane was in one piece, John tried some runs there, but was finding that the tail was staying on the grass and with only a small wheel, that end was being alarmingly shaken. Hence he moved the aeroplane twenty miles (32 Km) to RAF Benson. This meant that during all the flight trials, people from Halton had first to make this journey. During the first runs on the Benson concrete runways the tail still would not lift. Then John found that all that was needed was more speed to make the tail lift. This is due to the constraints of this type of layout with the concentric wheel and pedals, affecting the centre-of-gravity position relative to the mainwheel (see Puffin). On Jupiter, more weight is on the tailwheel than one wants for take-off.
I arrived at Halton on February 10th 1972 with a list of a few jobs which I considered needed doing before the plane was airworthy, to be informed that Jupiter had flown the previous day, twice. Three more flights were made on the 13th. On the last of these the wheel buckled on landing. I had seen none of these flights, and it was not until after the 25th February that I was able to write :-
A LETTER TO MY BROTHER .
"Dear Geoffrey 28th February 1972
"A great shame you couldn't be there on Friday (25th), actually we only just managed to get a flight as by the time we had put the wheel back on and a new chain and got it outside it was nearing darkness. I believe I told you the wheel was damaged on the fifth landing, and the people at Halton had only just repaired it and took it to the aerodrome with me on Friday, When we had put the wheel back, a task which was accomplished not without my local knowledge of the particular machinery, it was discovered that the wheel-drive chain had also been damaged during the landing, but luckily we had a spare length and the special tools at Benson. So this was then trimmed to the exact number of links and fitted. (The old chain which had made five flights was cut up and a short length given to several of those who had helped with the project.) We then opened the hangar doors, having got clearance to use the runway, and seeing that the weather was calm enough and trundled the machine outside, the wingtips just clearing the sides of the doors of the hangar which could take a Concorde. Taxi to end of runway, and you wish you had taken a taxi because you get more puffed out running alongside than the pilot who can cycle the machine at ten miles an hour with very little effort. Surprisingly, since the aeroplane only has two wheels like a bicycle this can be done without the assistance of anyone at the wingtip to hold it level because aileron becomes effective at quite an early speed, but assistance is required to help turn sharp corners on the ground since the wheels don't swivel to steer. So, having got to the end of the runway you have to point the plane in the right direction. There were only three of us there - John Potter, Ernie Moore and myself on Friday, which is the minimum, one inside and two ground assistants for handling and to put the cockpit hood on which is quite a knack as it has to mate up in several places at once. Having fulfilled these tasks, I was going to act as timekeeper of the flight, and Ernie as photographer. Two youths leaning against the enclosing fence of the aerodrome thought fit at this stage to shout to us "You'll never fly". On our first attempt that day we actually didn't, this was because I hadn't grasped the fact mentioned above re wing tip holding. I as wing tip holder had held on far too long as I ran alongside whereas I should have let go when the aircraft reached walking pace. All my previous wing tip holding had been with gliders. Ernie claims that it took off and he could see daylight under the wheel while I was still holding the tip. He may well be right, it turns out that the pilot finds it not clear to tell whether he is still on or just off the ground, and on this occasion the feel was further complicated by me holding on. I was looking forward and forty feet from the wheel all the time, and it was beginning to get dark. We waited for John P to get his breath back before making another attempt. Meanwhile I was thinking that if what I had just witnessed was flying then it was a bit low. This time he reached flying speed much quicker and when he left the ground there was no doubt at all that he was going up. What impressed me most was the rate of climb, particularly as my calculations had shown and I had read in several places that this would be a most difficult manoeuvre. The aircraft then levelled out to a height well above our heads and giving us the illusion of hovering. Then John must have given an extra burst of energy because the machine once more started to climb and then went off into the distance. Then I realised that I hadn't pressed the stopwatch. It certainly was a sight worth seeing. The day's events had very much taken the form of going upto a bicycle, fixing the wheel and the chain and then just wheeling it out of the shed and pedalling it into the sky. I have up to now felt insulted when the machine has been described as a "flying bicycle" rather than as an aeroplane, but once airborne the size is apparently lost amongst the vastness of the sky, and what has happened is that he's pedalled and its flown. It is a Flying Bicycle. He landed and we ran to the aircraft, and he commented on some minor adjustments we had made to the instruments. I felt that watching the flight was a worthwhile recompense for having travelled to Halton, travelled from there to Benson, worked on the wheel and the chain and done quite a lot of running along the side of the runway. The true cost, of course, is all those, but multiplied by you-name-it and then put a nought on the end, or two noughts. And whether I feel it was worth this true cost I can't say. Thinking about it since, sometimes I feel I can't say yes and sometimes I feel that I definitely can't say no.'
Geoffrey, to whom this letter was sent, came to Benson in June 1972 and observed the record-distance flight. As it happened he had the aggravation of a minor car-accident on the way. I asked him ( 1990 ) whether he felt it was worth it. `Yes, definitely', he replied.
(In 2002, Geoffrey himself became airborne under his own power pedalling the hovercraft, Steam Boat Willy. I remember that one too. An ex-marathon-runner, at the age of 62 he pedalled excessively on his first take-off and the craft shot away uncontrollably. But that`s another story. )
Two more flights were made on the 27th February, and three more on the 1st March. By the end of 19th March, twenty five flights had been made, the longest about a quarter of a mile.