- Interview with John Larroucau
- Birth of the Pup
- Pup Development
- Flight Testing
- The Beagle Pup – a View from Down Under
John Larroucau, Designer of the Beagle Pup
If it were not for his signature at the front of every Pup’s handbook, many owners today might not recognise the name John Larroucau. Yet this quietly spoken gentleman was the architect of the Pup and the Bulldog. Club member Tim Watson got the inside story.
As maiden flights go, it was not what you might have expected. No press cameras, no directors with their families, not even champagne on that April morning in 1967. Just a small group of men to push the red and white machine out of its hangar and begin the engine run-ups. The man in charge of the preparations was John Larroucau, the Pup’s designer, and by late morning he had everything ready. Was Larroucau even slightly nervous as he watched test pilot John ‘Pee Wee’ Judge and observer David Cummings strap in and takeoff? “Not at all,” he says, “Provided the engine didn’t stop, what could go wrong?” An hour or so later, as Judge landed and climbed out of the new Pup, he had just one word for Larroucau: “Brilliant!”
Beagle (an acronym of British Executive General Aviation) had been the brainchild of the legendary Peter Masefield, Managing Director of Bristol Aeroplane Company. Masefield nurtured the idea of developing an all-British, light twin executive aircraft. He created Beagle Aircraft Ltd by taking key design staff from Bristol, and acquiring the Auster and Miles companies for good measure. In John Larroucau’s opinion, the venture was doomed from the beginning. “It was an amalgam of three conflicting, politically irreconcilable, mutually self-destructive organisations,” he says.
The twin, which Masefield had conceived while at Bristol, was based on the Cessna 310. But at Shoreham, the various design teams had their own ideas. The result was an engineering hotchpotch called the Beagle 206X – overweight, underpowered, unstable about all three axes and unable to climb on one engine.
Beagle clearly needed skilled help and Larroucau was hired from Avro, where he’d worked on the Vulcan and the 748, to be Chief Structural Engineer on the troubled project. After several rounds of major re-engineering and three attempts to find the right engine, the aircraft was actually able to meet certification rules. At last Beagle had a product it could sell.
But after 5 years of costly development, the company was in a desperate financial state. The 206 was selling quite well in America, but its development had already swallowed £3 million with no end to further expenditure in sight. To make matters worse, rivalry amongst the various design teams was rife and personality clashes between Masefield and his Technical Director, George Miles, led to Miles pulling out of the company, taking many of his key people with him. And John Larroucau was considering the wisdom of having left his secure job at Avro. “As a career move,” he says with a grin, “it was not the world’s greatest”.
John has an amazing recall of the complex events of more than thirty years ago. He’s a delightful, self-effacing man who laughs a lot as he recounts the ups and downs at Shoreham. His secretary from those Beagle days, Margaret, remembers her old boss as “A little like the absent-minded professor. but brilliant!” So when Masefield decided to broaden the company’s product base with a new single-engine tourer, John Larroucau, now Chief Engineer was asked to design it.
“We didn’t have words like ‘mission’ in those days,” says John, “we just built aeroplanes we thought we could sell.” But an article in Shell Aviation News in 1967, reported that the aim was to build: “…the equivalent of the British sports car; agile, robust and fun to handle”.
So, with a blank sheet of paper and an aeroplane to create, where do you begin? “The first thing you do is to create the cabin,” says John, “get that right, and it all proceeds from there.” In fact the roomy cabin that he designed, and its ability to comfortably seat two pilots in full survival kit, would be a key factor in the success of the Pup’s later military variant, the Bulldog.
Beagle always envisaged that there would be at least two variants of the Pup – the 150hp version and a 100hp model that, with its lower cost, they hoped would sell in greater numbers. With the benefit of hindsight, John feels that the 100hp engine was a mistake – that it imposed restraints that severely handicapped the design process.
One early challenge concerned running the control cables through the aircraft. John’s solution was to add the centre console running fore and aft through the cabin to accommodate them, but the obstruction this created had the unfortunate effect of requiring the aircraft to have two entry doors. To keep cost and complexity to a minimum, John wanted simple gull wing doors in smallish apertures, but the Sales Department wouldn’t wear it. Instead they insisted on the large car-like doors they believed customers would prefer. Ironically, it was the unreliability of these doors that would be a factor in the eventual downfall of the Pup programme, and of the company despite some work eventually being undertaken on a gull wing door version of the Pup.
The doors issue was just one of a number of battles between design and sales. Another concerned the control sticks. Sales had wanted the Pup to have control wheels, which, they felt, would make Cessna and Piper pilots feel at home. John argued that a sporting machine designed for aerobatics must have sticks. And so it did.
Initial flight-testing of the Pup went well and performance equalled, or exceeded, the figures that had been estimated at the project stage. Spin recovery, though, was marginal and despite the commercial pressures, John halted the test programme until he could correct the problem. His solution was to add small strakes ahead of the tailplane and to modify the shape of the rudder and fin. It did the trick, but there was opposition from an unexpected quarter. The original fin had been styled to be a scale version of (of all things) the Vulcan’s. It was a detail of which Peter Masefield was particularly fond, and he hated to see it changed. But some quick thinking on John Larroucau’s part convinced him that the shape of the new fin was now like Concorde’s, and that a ‘supersonic’ tail would do no harm to the Pup’s appeal!
Not long after the first flight, in May 1967, a naming ceremony was held at Shoreham. Beagle had to get permission from Hawker Siddeley – owners of the Sopwith marque – to use the ‘Pup’ name. Not only was permission granted, but Tommy Sopwith himself performed the ceremony, with the last airworthy example of his own Pup N5180 there on the grass beside the new machine.
And when Flight International tested the new Pup, the reviewer was ecstatic: “Halleluja!” he gushed, “Here is the good news we have waited for for so long.the Pup is likely to become the standard trainer for military and commercial instruction as well.the export potential is terrific.”
But the company was still losing £1 million per year; its owners were tired and wanted out. As Beagle faced extinction, Peter Masefield, ever the skilled persuader got the Government to take it over.
Now the pressure was on to rush the Pup into production and as they did so, some ‘man-sized’ reliability problems emerged. “Generally you expect problems with a brand new design,” says John Larroucau. “And you expect to have to do some intensive in-service testing before you release onto the market”. John had always assumed they would build an initial batch of 50 aircraft and then iron out any service problems. They would also take a look at ways of making the structure less expensive to produce. The dire financial situation meant that none of that happened. Brake problems, engine mount cracks, leaking fuel tanks, doors opening in flight; the list of difficulties that owners were experiencing was endless. And meanwhile, Beagle was starting to get a very bad press.
Meeting with Tony Benn at Shoreham
Eventually even the Government had had enough. On a fateful December morning in 1969, John Larroucau, now Technical Director, and the rest of the Board were summoned to London to hear Anthony Wedgwood Benn tell them he was pulling the plug. For John and the rest of the staff who were thrown out of work, there were few opportunities in the rapidly shrinking British aircraft industry. Eventually he joined the Jetstream programme at Prestwick, but it took him 13 years to regain the status he’d enjoyed at Beagle.
At 71, John still undertakes consultancy work for the aerospace industry and in pride of place in his study is the painting of a Pup that the Club presented to him in 1992. He enjoys the newsletters that he receives as an Honorary Member and keeps in touch with his friend Peter Masefield and other colleagues from those days.
And what became of his secretary Margaret? Well, of course, she married her brilliant boss and today John and she spend their time indulging a shared love of travel, the arts and their grandchildren. She’s also proud of the fact that their son Mark, an Airbus pilot with Monarch, learned to fly on the plane his dad designed – a Bulldog of the University Air Squadron.
Looking back on the Pup and the Bulldog, I asked John what he was most proud of. “The handling qualities,” he replied. “But it was no accident, we had to work hard at it.”
Tommy Sopwith’s original Pup was described at the time as more of an inspiration than a design. It was reputed to be one of the most delightful pilots’ aircraft ever built. Today, those of us who take pleasure in flying our machines would readily agree that John Larroucau’s Pup was likewise, an inspiration.
Thank you, John!
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Birth of the Pup
From the original Beagle News
The Beagle Pup has introduced a new generation of light aeroplanes – new in looks, new in performance, new in character – and it may be of interest to review how this fresh approach to a worldwide requirement was generated. First, market analysis had shown that there was a widespread demand for a single-engined two-seat training aircraft, and also for a single-engined, four-seat touring aircraft. It was also apparent that for training and club aircraft the requirement was for good all-round flying and aerobatic characteristics, although it was noticeable that these criteria were valued more in the world market as a whole than in the U.S.A. in particular. It was, therefore, decided that the new Beagle aircraft should be of a type that would specifically meet these market requirements and, at the same time, serve as the basic design for a range of future aircraft. In defining the base aircraft it was obvious that the specification would need to differ materially from that of existing American light aeroplanes. The aircraft would need to meet the requirements both of BCAR Section K and FAR 23 in toto and without exception, and it would also need to be produced for the lowest possible initial price and have the lowest possible operating costs.
Research and analysis had established that the required characteristics were: all-metal low-wing monoplane; faultless flying qualities-good stability and manoeuvrability; first-class ground handling-steerable nosewheel and toebrakes; aerobatic capability and unlimited spinning within the semi-aerobatic category envelope; two-seat side by side configuration; good performance, particularly in rate of climb to provide quick ascent to training altitude; well-cooled easily handled engine; optimum reliability; ease of servicing and maintainability; wide cabin giving plenty of elbow room; ease of entry to both seats, preferable by door on each side; stick control rather than steering wheels.
The 100 h.p. Rolls-Royce Continental engine was chosen because it is built at Crewe and is both widely known and well supported throughout the world. Quick calculation of rough power loading, wing loading and weight performance gave a gross weight of 1,600 lb. and an empty weight of 950 lb. The wing was then considered and it was decided that with reasonable section characteristic and efficient flaps a suitable performance could be obtained from an area of about 120 sq. ft. A plank wing was the first thought but further study showed the overall advantages of a tapered wing which, in the event, requires no more man-hours to produce. The section chosen was NACA 632615 with the lower cusp eliminated to improve torsional stiffness of flaps and ailerons. This section offered the structural advantage of a maximum thickness sufficiently far back to allow use of a single main spar, and the aerodynamic advantages of good stalling characteristics, a high basic CL shift and, with a 21/2 deg. washout, we thought we should get a good nose-down pitch at the stall without tendency to drop a wing. We chose an aspect ratio of just over 8 and a taper ratio of 0.5 to give a reasonable span loading and, hence, good climb performance, whilst providing sufficient length to have large-span constant-chord flaps and ailerons.
In general configuration terms we attempted to keep the aircraft as short as possible, reducing both cost and weight. But this dictated a rather larger horizontal tail surface for stability reasons and, since most of the ribs would be the same, we adopted a parallel planform. From the earliest design doodles the fin and rudder have blended into the rear fuselage, the deep rudder and ventral fin being considered necessary for good spin recovery. Spinning the Pup-100 presented no problems. On the Pup-i 50, however, due to the increased pitching inertia of the heavier engine, we did get occasional wing drops with the cg at the aft spinning limit of 27.5% SMC, and application of out-spin aileron promoted a flatter spin with slow recovery.
We therefore drooped the leading edge of the outer wing to provide aileron effectiveness throughout the stall, and to increase the anti-spin damping moments we added fuselage strakes ahead of the tailplane roots, reduced the rudder chord at the top and increased it at the bottom. These modifications combined to produce rapid and faultless spin recovery, the rate being 3/4 to 1 turn after 8 turns. Although not in themselves necessary for the Pup-150, these alterations were standardised for both types in the interests of uniformity in production.
An unusual and, perhaps, significant design decision-and one that has been widely criticised -was to use stretch-formed sheet for the fuselage and integral fin skinning. The Pup probably has more double curvature panelling than any other mass produced light aeroplane. The decision was taken for three reasons: (i) we had a stretch-form machine, (ii) the inherent stability of a three-dimensional panel reduces the need for internal stiffening and so reduces weight, (iii) the method makes for a cleaner finish and an
aesthetically more pleasing and aerodynamically more efficient shape. In the event, excellent fuselage stiffness has been achieved and in high speed dives the aircraft is entirely free from vibration and distortions. The fuselage structure is of entirely conventional semi-monocoque form with riveted skins, frames and few stringers. The stretch-formed panels are mainly 24 swg., increasing to 20 swg. in the centre section and decreasing to 26 swg. in the cabin roof. The frames and stringers are mainly 24 swg.
For cost and weight reasons we chose a fixed landing gear and we investigated rubber in torsion, flat steel and glass reinforced plastics: all had disadvantages of greater or less degree and we opted for an oleo-pneumatic system as being the lightest, most rugged and the one most likely to give excellent performance on the rough fields which abound in the U.K. and so many other countries. All wheels are interchangeable and tubed tyres were decided upon to obviate the deflation sometimes experienced with low-pressure tubeless tyres.
Finally, the control surfaces: the simplest type of metal construction was chosen for these, but (for maximum safety) with multiple hinge points four on each aileron and three each on the others. Friction in the control circuits has been kept low by the use of ball bearings in all hinges, pulleys and bell-crank assemblies; and in the interests of simple servicing all hinge bearings and housings are interchangeable between all control surfaces.
We were as thoughtful and skilful in designing the Pup as we knew how to be, but luck was on our side too. We did our sums right individually, but it happened that together they have a harmony that makes the total better than the sum of the component parts, and it is this quality that makes the Pup the extraordinarily good little aeroplane that it is.
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In this report John Larroucau, Beagle’s Chief Engineer and Chief Designer, traces development of the B.121 Pup-100 to date. The aircraft first flew on Saturday 8 April, 1967, and up to June 29 had made 108 flights totalling 77 hours. On May 24 the initial assessment and development of the aircraft had been completed to a sufficiently high degree for the award of a Special Category Certificate of Airworthiness. This included demonstration of the handling qualities of the aircraft over the complete centre of gravity and speed range required for full certification.
Ground handling is extremely good and take-off, landing and taxiing present no problems. The only refinement under this heading has been the reduction of the maximum nosewheel steering angle from =/-30 deg. to =/-25 deg., for less steering sensitivity during crosswind takeoffs and landings on hard runways.
Longitudinal stability has been exemplary throughout, right up to the extended aft centre of gravity position or 33% smc, the light downspring contributing sensibly to the stick free margin. Initially, the stick force per g was unacceptably light – not as a result of lack of manoeuvre margin, but due principally to the small elevator chord and lack of anti-balance tab. It was quickly brought up to a reasonable value in the region of 7 or 8 lb per g by increasing the total elevator travel from 40 deg. to 50 deg., and reducing the stick travel from 10 in to 7.5 in. Trimability in the nose-up sense was initially inadequate to meet British Civil Airworthiness Requirements Section K, but this has now been met by increasing the downward movement of the elevator trim tab.
The major part of the initial flight test assessment was concerned with producing faultless qualities at the stall, in particular complete freedom from wing drops and a good nose-down break-qualities so essential to a successful trainer. These qualities have been achieved by means of the wash-out featured in the initial design of the wing and the addition of small leading edge strakes outboard of the root. The stall behaviour so established is satisfactory under all the various configurations of BCAR Section K.
The lateral stability and the behaviour in sideslips are extremely good. Rate of roll is brisk, and the slight adverse yaw due to ailerons, initially pinpointed during the maiden flight, has been cured by rigging the ailerons 3 deg. up and introducing a slight revision to the aileron nose profile. Barrel rolls can now be executed feet-off.
The aircraft has been cleared for normal aerobatic manoeuvres. These have included barrel rolls, loops, half loop and roll out, stall turns, within the permissible 4.5 g limitation and the demonstrated design diving speed of 170 knots lAS.
One-turn spins in various configurations were carried out prior to the Paris Air Show but these are now being supplemented by a more extensive spinning programme aimed at clearing the aircraft for unlimited spinning.
The aircraft was extensively tufted during its initial flights, and only minor attention has been required at local fairings and at the nose cowl in order to produce smooth flow all over the airframe. All performance measured to date has been equal and in many instances, such as rate of climb, markedly superior to the performance figures estimated at the project stage.
It will be seen that the development of the Pup-100 has been remarkably free from major problems. The handling qualities of the aircraft are beyond all doubt measurably superior to those of competitive aircraft and will ensure its wide acceptance as an ab initio trainer and club aircraft. In parallel with the flight tests, an equally concentrated engineering effort is being applied to the completion of the structural test programme. To date the critical wing bending and torsion tests have been completed on a full-scale static test specimen. This is at present being prepared for the major fuselage bending and torsion tests. Further tests are underway at Lockheed Precision Products Ltd and Dunlop Company Ltd to demonstrate compliance of the undercarriage and wheel and brake equipment with requirements.
Throughout the flight trials, special attention has been paid to the reliability of all components, operations to date having proved completely free from defects. Further aircraft as they become available will be subjected to extensive flying programmes in order that the reliability of all components may be probed to a still greater depth. This is the way to ensure that when Pups first reach operators in the first half of 1968 they will do so with the widest possible background of operating experience and will quickly establish themselves not only by their flying qualities, but also by their complete reliability and ruggedness.
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by J. W. C. Judge, Chief Test Pilot, Beagle Aircraft.
The first three prototype Pups have been engaged in the certification programme. The first aircraft (001) is the prototype Pup 100, G-AVDF, with 100hp Rolls-Royce-Continental 0-200-A engine. The second (002) is the structural test airframe and has been subjected to tests in the structural test house at Shoreham concurrently with the flight test programme on the other two aircraft. The third aircraft (003) is the prototype Pup 150, G-AVLM, with 150hp Lycoming 0-320 engine.
The prototype Pup 100, G-AVDF, made its first flight at Shoreham on 8th April 1967 and it was immediately apparent that the aerodynamicists had got their sums right and that this was indeed going to be a very good little aeroplane. Stability about all axes was excellent and the controls had a pleasantly “European” harmony and effectiveness. The trim change with power was suitably mild and the trim change with flap was virtually non-existent (this coupled with the generously high limiting flap speed of 100 kts. makes the Pup easy to handle in a busy traffic pattern). The well damped oleo pneumatic undercarriage gives a comfortable ride over the worst bumps that Shoreham has to offer and is equally at home on smooth tarmac surfaces. Crosswind take-offs and landings have been made with 25 kts. wind at 90 deg. and the aircraft has been taxied and flown in gusts up to 45 kts. The early flight testing was aimed at obtaining a Special Category Certificate of Airworthiness to enable the aircraft to be flown at the Paris Air Show and in addition to normal handling tests, this included an aerobatic clearance for which the A.R.B. requires preliminary spinning trials (1 turn).
The Pup’s public debut at Paris caused approximately ten days’ delay in the already “tight” certification flight test programme, but it was considered worthwhile to “show the flag” in this, the major International Air Show of the year. On returning home, full spinning trials were completed, involving 8 turns (and sometimes more due to losing count) before taking recovery action. The spin is classic and recovery is in all cases prompt. During this phase of the trials use was made of a Husky as observation “chase” ‘plane, the
Husky’s good reserve of power, slow flying ability and all-perspex door made it particularly suitable for this task.
Temperate performance and engine cooling tests preceded the aircraft’s departure for hot weather trials on the 25th July. For these we took a leaf out of the French light aircraft industry’s book and went to the South of France, accompanied by a B.206 carrying the remainder of the trials party and equipment. The trials site chosen was Montpellier/ Frejorgues, a friendly airfield beside the Mediterranean which proved very suitable for our programme, consisting of engine and equipment cooling tests and performance trials (climbs and measured take-offs and landings), The second part of these hot weather trials, consisting of measured take-offs and landings at high altitude were conducted at a military airfield in Switzerland thanks to the cooperation of Colonel Liardon and Doctor Eichenberger of the Federal Air Office. The remaining items of temperate performance, systems tests and instrumented flight resonance up to 180 kts. were completed on returning to England.
The prototype Pup 150, G-AVLM, joined the development flight test programme on 4th October 1967 and we were pleased to find that it duplicated the pleasant handling characteristics of its little brother despite a 50% increase in power. This power, needless to say, results in a decidedly lively performance.
To date (late December), flight trials on the “150” have been concerned with preliminary handling, performance and systems tests but we have already done enough to know that there are no awkward problems. Spinning trials will commence early in the new year and we are confident that the full certification flight test programme should go through with no more difficulty than with the “100”.
We feel that in the Pup family we have an outstanding little aircraft which is in a class quite by itself, combining the comfort and amenities of the best of its contemporaries with an up-to-date and efficient structure, really good handling qualities and complete aerobatic capability.
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The Beagle Pup – a View from Down Under
By Stewart Wilson
Below is the text of a story on the Pup I wrote for Australian Aviation magazine’s August 1997 edition. It was the 13th of a series of 60 ‘From The Cockpit’ articles I did for the magazine over five years, these describing the histories of various light aircraft and some brief flying impressions of them. I had to stop the series at 60 because I ran out of aircraft I’d flown. I also covered the B.206 and Airedale later on.
If the Beagle company was trying to create something of a renaissance of the British light aircraft industry it came close to it with the Model 121 Pup two-three seat single engined training and touring and touring aircraft. This month, From The Cockpit looks at this delightful but ultimately commercially unsuccessful aeroplane. The Pup was most certainly successful in its intended roles and looked as if it was going to succeed in the marketplace but a potentially long production life was thwarted by the financial problems of its manufacturer. The project was terminated less than two years after the initial deliveries had been made, ironically while the company held a very healthy backlog of orders.
Beagle (British Executive and General Aviation Ltd) was an amalgamation of the famous British light aircraft manufacturers Auster and Miles and was established in October 1960 with the intention of designing and producing light aircraft and hopefully returning Britain to the pre-eminent position it once held in that field.
The company’s first products were civil conversions of ex military Austers and new versions of the same aircraft, followed by the Airedale, a four seater of the Auster type but modernised and incorporating tricycle undercarriage. Doomed to failure as it was heavy, old fashioned, of mediocre performance and had to take on the much more modern all metal Cessna 172 and Piper Cherokee, Airedale production reached the grand total of 43, several hundred short of the breakeven point.
This in combination with losses sustained on the Auster conversion programme (nearly twice as many man-hours were required to perform the conversion than to build the original aircraft!) left Beagle in a precarious financial position. Its next production project, the B.206 medium twin was a fine aircraft but development of a commercially acceptable variant took too long and sales were disappointing with only 79 built of all versions. The production version of the 206 was originally designed for the RAF as a communications aircraft but instead of buying the expected 80, the RAF ordered only 20, creating more financial pressures on the company.
Beagle was originally established as a subsidiary of Pressed Steel, which was subsequently taken over by the British Motor Corporation. BMC looked at Beagle’s balance sheet (and the several million pounds it had already absorbed), decided it wasn’t viable and immediately began talks with the British Government, which took over its assets in December 1966.
Enter The Pup
In early 1967 things looked good for the company with a stable financial footing apparently established, the commercially viable 206-S in production (although by now against intense competition from the Cessna 400 series and Piper Navajo) and the forthcoming Model 121 Pup already attracting an enormous amount of interest. The Pup’s design owed nothing to previous Auster influence but had its origins in the Miles M.117 project, an aircraft intended to extensively use plastics in its construction. The Pup would dispense with these and revert to an all metal design, and as originally proposed would be developed into a series of light aircraft ranging from the basic 100hp (75kW) B.121C two seat trainer through more powerful four seat fixed and retractable undercarriage variants and even a twin engined model. A fully aerobatic 210hp (156kW) military version was also proposed as the B.121M Bull Pup.
As it finally emerged, the semi-aerobatic Pup (which featured dual control sticks rather than the more common wheels) was built in three versions, all identical aft of the firewall: the two seat B.121 Series 1 Pup 100 with 100hp (75kW) Rolls-Royce built Continental 0-200-A; the two-three seat (or two adults and two children) B.121 Series 2 Pup 150 with 150hp (112kW) Lycoming 0-320-A under a revised cowling shape; and the similar apart from its powerplant B.121 Series 3 Pup 160 with fuel injected 160hp (119kW) Lycoming IO-320.
The latter model was originally built to the requirements of the Iran Civil Air Training Organisation and both it the 150 had increased optional fuel capacity compared to the 100.
The prototype (a Pup 100) was flown on 8 April 1967 and the first Pup 150 flew in October of the same year. Deliveries of the 100 began in April 1968 with the 150 following the next August. The prototype Pup 160 (converted from the first 150) flew in September 1968 and the first production example of this model appeared in January 1969.
Production and Problems
Production built up gradually and during 1969 it became obvious Beagle was suffering severe cash flow problems. The Pup was a relatively complicated design with many curved surfaces which did not lend itself easily to mass production, but more to the point, Beagle was selling the aircraft for less than it cost to build! Sluggish B.206 sales and a high inventory level of that expensive aircraft contributed to the problem.
The situation became critical in late 1969 when the British Government refused to give Beagle the £6m aid it had requested.
The company went into receivership in November 1969 and into liquidation in January 1970 by which time some 152 Pups had been built of which just under 130 had been delivered. Production had peaked at the rate of 15-16 per month (with further expansion planned) and orders were held for a further 276 aircraft.
The undelivered aircraft subsequently went to customers and other nearly complete Pups were later assembled and delivered, most by Domestic Wholesale Appliances Ltd, which acquired them from the receiver. The last of these was completed in 1974, bringing the total Pup production tally to 173 aircraft – 66 Pup 100s, 98 Pup 150s and nine Pup 160s.
Beagle had in the meantime developed a military version of the aircraft, the B.125 Bulldog. Fully aerobatic, featuring a sliding bubble canopy and a 200hp (149kW) Lycoming IO-360 engine, the first prototype was flown in May 1969.
Subsequent development and production of the Bulldog was successfully taken over by Scottish Aviation (later part of British Aerospace) which built over 320 for the Royal Air Force and export. The last Bulldog was delivered in 1982.
Flying and Buying
It’s a pity the Pup’s development and production was halted when it was because it was a superb aeroplane ideally suited to flying training and an absolute delight to fly. As a trainer it was regarded as ideal because although easy for a novice pilot to fly competently and safely, it rewarded and encouraged accurate and precise handling. The Pup looked fresh and new (which it was) compared to its American rivals both inside and out.
Access to the wide cabin was via a door on each side, the interior featuring a ‘sports car’ look with a centre console between the seats housing throttle, mixture, trim and electric flap controls plus switches, fuel gauge and ammeter further forward. A second throttle could be installed on the port side of the cockpit (for right handed flying) and the instrument panel was of the old style ‘T’ pattern with everything laid out just as it should be – a lesson for the designers of some light aircraft panels who seem more interested in appearance than function.
The bucket seat squabs are fixed (although the rake is adjustable) and adjustable rudder pedals provide the necessary leg length variation to suit most pilots. It’s tight but manageable for very tall ones. Although capable of carrying three adults (or two plus two children), the Pup 150 is normally regarded as a two seater with useful luggage capacity. With two adults aboard a range of about 400nm (740km) can be comfortably achieved with full fuel and reserves while cruising at around 105 knots TAS (195km/h).
The Pup 150 is started by a push button starter rather than the usual key and management of the engine is the same as any other aircraft powered by the venerable Lycoming O-320. Fuel is contained in two connected tanks per wing in the 150 (one per wing in the 100) with the fuel cock located on the floor in front of the left hand seat and marked Off-L-Both-R. The setup of the single fuel gauge is unusual – it does not show total contents but rather the remaining fuel on each side, individually and separately selectable by a switch and then mentally added together to arrive at the total.
In the air the Pup excels, with beautifully responsive and balanced controls with that indefinable ‘British’ or ‘European’ feel to them. Although the large and effective rudder feels slightly heavy at first by comparison with some other aircraft, it is quickly adapted to. Aerobatics in the Pup (especially the 150 with more power) are a great joy and the aircraft is cleared for the normal manoeuvres including spinning and even flick rolls. Despite its relatively low power, the Pup 150 can be strenuously aerobatted by an expert without any loss of height. Like any other aerobatic aircraft with a fixed pitch propeller, engine overspeeds have to be watched.
Even more important is the need to remember that the Pup is officially ‘semi aerobatic’ – that is stressed to +4.4/-1.8g at the appropriate weight and not the +6/-3g of a fully aerobatic aeroplane. More on that below.
In 1989, the Australian Civil Aviation Authority’s Fatigue Evaluation Section published a document entitled The Control of Fatigue in General Aviation Aeroplanes. In it was the following line: “It is unusual for small aircraft to suffer various fatigue problems, but a few, such as the Piper PA18 and the Beagle Pup, managed to achieve it”. Singling out the Pup for special mention is indicative of the fact that the aircraft has suffered some problems in this area over the years. Indeed, an Airworthiness Directive (AD/BEA 121/31) relating to the main spar and wing to fuselage attachments was issued as recently as March this year. The following comments are offered as a subjective assessment of the situation, based on experience with the Pup early in its career but none (unfortunately!) in recent times. The problem seems to stem not so much from any inherent structural problem in the Pup (and the writer is open to correction here) but more to the nature of the aircraft itself. It is important to recall that the Pup is semi-aerobatic (stressed to only 4.4/-1.8g) but its superb aerobatic flying qualities lend it to easily exceeding those limits and thus creating fatigue problems. Overstressing of the Pup’s airframe was therefore a not uncommon occurrence as a result. The writer remembers a period in about 1971-72 when several Australian Pups had to have their wings reskinned and I think resparred due to this at a time when the aircraft were only two or three years old.
The memory’s slightly foggy on this but what is vividly recalled is a flight in a Pup due for this work to be done during which an experienced Pup pilot demonstrated to me what happens to the aircraft’s wings during strenuous aerobatics. The sight of some of the wing rivets merrily popping up and down was not one I’ve quickly forgotten!
Beagle saw a large potential market in Australia for the Pup and this proved to be case. By the time the company folded 11 150s had already been delivered and a further 10 completed, flown and awaiting shipment from the UK. These were subsequently sold in other countries. A couple of writeoffs and the sale of aircraft gradually decreased Australia’s Pup population to a point where it settled down to about three from the late 1970s. The current number is four as one or two have recently been imported from the UK.
Given the small population of Pups in Australia, it’s rare to find one for sale but there happened to be one on offer during the preparation of this article. It’s a low time Pup 150: TT 2585, ETR 1600, PTR 1522, new paint, windscreens and interior, price $60,000.
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