Kraków 2012-07-22
PZL-Mielec M-20 Mewa / Piper PA-34 Seneca II .
255b Section 25.07.1979 year. Poland.
PZL M-20 Mewa is a disposable aircraft produced in PZL Mielec.
Before we describe the PZL M-20 Mewa aircraft, we must write a little about the Piper PA-34 Seneca II aircraft, which was a license model of the Polish Mewa.
Piper Aircraft.
Piper Aircraft is an American company, one of the most recognizable aviation companies in the world. It was founded in September 1927 by brothers Clarence Gilbert Taylor and Gordon A. Taylor in Rochester, New York as Aircraft Manufacturing Company Brothers. A little later it took the name Taylor Brothers Aircraft Corporation. Gordon A. Taylor died in a plane crash in April 1928. At this time, the company was encouraged to move production to Bradford, Pennsylvania. Here, the company had better premises and financial support from local entrepreneurs. One of them was William T. Piper. However, the company began to run into financial difficulties. William T. Piper bought back the company’s assets and effectively began to manage it. The relationship between Clarence Gilbert Taylor and William T. Piper did not go well. In December 1935, William T. Piper bought out the entire company. On March 16, 1937, a fire destroyed the Bradford factory and the company moved to an abandoned silk factory in Lock Haven, Pennsylvania. In November 1937, the company was renamed Piper Aircraft Corporation. (That’s why in 2012, the company celebrated its 75th anniversary, although it was actually its 85th anniversary.).
The period of World War II was a good time for the development of the company, which was still operating in Lock Haven. However, after the war, these facilities proved insufficient and the company gradually moved to Vero Beach Municipal Airport. From 1950, subsequent models of aircraft began to be named after the names of Indian tribes. In 1972, Hurricane Agnes almost completely destroyed the Lock Haven facility. In 1972, Piper opened a manufacturing facility in Lakeland, Florida. In 1977, facilities in Pennsylvania closed. The years that followed were ups and downs. The recession of 2008 forced drastic decisions to keep the company on the market. Employees had to go on unpaid 4 weeks of work a year. The financial support of the US authorities allowed for the preservation of jobs. In 2011, the company was still struggling with financial problems, which may be overcome mainly by economic recovery.
Maybe this story is a bit scary, but Piper Aircaft is a good American company that will not disappear from the market soon. This is a company created and still created by enthusiasts. There are few aircraft manufacturers with as much experience as Piper Aircaft. Since 1937, the company has designed and implemented over 100 types of aircraft for serial production, of which over 130,000 have been produced to date (2012). From the very beginning, Piper has excelled in the construction of corporate aircraft. Apart from technical excellence and high quality, Piper aircraft are also easy to fly and have a high level of safety. Piper Aircraft engineers have long been designing aircraft with the philosophy that safety is not just about strong construction. Safety is also, and perhaps above all, the predictability of the aircraft’s behavior in flight. Often pilots say that Piper planes fly by themselves.
Years of experience in the production of aircraft have resulted in a wide range of models, the offer of which is able to meet almost every customer’s expectations. Two models of four-seaters, four six-seaters and a turbojet aircraft under development make Piper Aircraft one of the aircraft manufacturers with the widest range of aircraft offerings.
It was generally said that Piper Aircraft made executive planes. But under this term there is a whole range of various aviation tasks. From typical passenger transport, through tourist flights, to specialized versions, such as transport of the sick and injured in accidents, or search and rescue tasks.
Piper PA-34 Seneca.
Since 1966, Piper has developed a new 2-engine, 6-seat corporate aircraft. Initially, the Seneca I version was developed. The phenomenon of this design is that currently (2011) the aircraft is still produced in the Seneca V version. And it seems that this model will be produced for the next few years. The construction is lightweight and the machine is mainly used for private (family) flights and as an air taxi for various companies.
The starting point for the development of the Piper PA-34 Seneca I aircraft was the design of the single-engine Piper PA-32 Cherokee Six aircraft. The first prototype of the Seneca aircraft received two engines mounted in nacelles in front of the wings. Interestingly, the engine placed in the nose of the aircraft was left. So, the plane had 3 engines. The construction received the designation PA-32-3M. The aircraft was registered as N3401K and made its first flight on April 25, 1967.
The 3-engine powertrain was obviously not promising. Resigning from the engine placed in the nose of the machine, the aircraft designated PA-34-180 Twin Six was developed, with Lycoming O-360 engines, with a power of 2 x 180 hp (2 x 134 kW). The aircraft still had a fixed landing gear with a nose wheel.
The second prototype, already equipped with a retractable landing gear, made its first flight on August 30, 1968. During the trials, the wingspan was increased by two feet.
The third prototype was flown on October 20, 1969. It received more powerful engines, the Lycoming IO-360-A1A, with 2 x 200 hp (2 x 149 kW). Importantly, one propeller rotated to the right, the other to the left. This has been achieved by modifying the engine, which has been given the index "L", which means that the shaft rotates in the opposite direction. This arrangement, although complicating the design, eliminated the critical limitations of the twin engines, improved control and increased safety in the event of one of the engines being cut off. The aircraft was designated PA-34-200 Seneca I and became a model for serial production.
The tests of the aircraft were completed on May 7, 1971. Production started at the end of 1971, and from 1972, the machine was already offered for sale. The total weight of the PA-34 Seneca I was 1,810 kg. Subsequent serial aircraft were retrofitted and their take-off weight increased to 1,910 kg.
The experience gained from the operation of the first units resulted in the development of an improved version of the PA-34-200 T Seneca II. The control surfaces have been improved. Engines with better performance at higher altitudes, turbocharged, 6-cylinder Continental TSIO-360 E/EB were used. The arrangement of opposite rotation of the propellers has been preserved. The layout of the seats in the cabin has been changed; the second row was placed rear-facing, which allowed for a large amount of legroom. Gross weight increased to 2,070 kg. The first flight was made on September 23, 1972. The aircraft was certified on July 18, 1974, and was produced from 1975. As many as 2,588 copies were built. Average annual production was 375 machines.
PA-34-220 T Seneca III is another version. The aircraft received new Continental TSIO-360-KB engines with 2 x 220 hp (2 x 165 kW), albeit only for 5 minutes, and continuous power is 2 x 200 hp (2 x 149 kW). The aircraft was certified on December 17, 1980.
PA-34-220T Seneca IV was certified on November 17, 1993. The aircraft received many minor innovations, although the powerplant remained unchanged.
PA-34-220T Seneca V was certified on December 11, 1996, and has been produced since 1998 until now (2011). Among other things, the aircraft received new engines; Continental TSIO-360-RB. The take-off weight increased to 2,155 kg. Monitors were installed in the cabin instead of analog instruments.
From 1975, the Seneca aircraft was built under license in Brazil by Embraera as the EMB-810; PA-34-200T–EMB-810C (452 built) and PA-34-220T–EMB-810D (228 built).
PZL M-20 Mewa.
The backstage of obtaining a license for the PA-34 Seneca aircraft for WSK PZL-Mielec is not fully known. The 1970s were a period of relative opening of the Polish People’s Republic to the world, including industry and the US market. However, this does not mean that contacts with Moscow have been broken off. At PZL Mielec, under the direction of Soviet designers, intensive work was carried out on the world’s first agricultural turbojet aircraft M-15 Belfegor. In Mielec, the transport aircraft An-2 was produced in huge quantities for the needs of the Eastern Market. At the same time, PZL Mielec cooperated with Rockwell Commander on the Thrush aircraft, which was used to create the M-18 Dromader agricultural aircraft. We will also mention the production of Melex electric vehicles, which were exported in large quantities to the USA as golf carts.
At the same time, it must be remembered that at that time all key decisions were made by the PZPR party, which in fact ruled Poland. It was impossible for the decision to purchase a license to produce the PA-34 Seneca to be made by anyone other than the Central Committee of the Polish United Workers’ Party (KC PZPR). At that time, the first secretary was Edward Gierek, who came to power after the workers’ revolt on the coast in December 1970. During his rule, the Polish nation gained the first direct contact in many years with the Polish diaspora in Western Europe and the USA.
Talks with Piper Aircraft on the Polish side were conducted by high-ranking party officials, and they probably began as early as 1975. The problem was the lack of the so-called hard currency, i.e. US dollars. Polish zlotys were non-convertible. But there was a solution for that too. The license was to be repaid with products and components manufactured in Poland. What’s more, the Americans agreed to the installation of engines already produced in Poland in licensed aircraft; PZL-Franklin. In addition to the license, Poland obtained the right to sell machines to foreign markets, specifically to Eastern Markets. If you want, you can, even in communist times.
Was the PA-34 Seneca aircraft necessary for the Polish economy? Of course. At that time, the Polish air force did not have a good, small, twin-engine aircraft for several people. The needs of the national carrier PLL LOT for communication pilots grew. They were trained using An-2 aircraft, which did not fit the training for An-24, Il-18, Tu-134 and Il-62 communication aircraft. Not only is the lack of a multi-engine powerplant, but also the landing gear layout with the rear tailwheel. In military aviation, large Il-14 or An-26 planes with two or three passengers were sent on routes. Medical aviation was developing, which lacked fast and cheap to operate aircraft. This type of plane would also be useful for the civil militia and border guards. It would be suitable for patrolling the Baltic Sea. Or maybe in the future, for typical business flights for which it was developed.
In January 1977, the management of PZL concluded a contract for the construction of the aircraft with Piper Aircraft. The aircraft was designated PZL-112. The contract assumed that the plants would send aircraft components to the USA, and in return assemble aircraft with Polish PZL-Franklin engines.
As it turned out, it was a preliminary agreement and had to be approved by the highest authorities. Let us realize that Poland and the USA were then in opposing political, military and economic camps. Therefore, in the US, the contract had to be approved by the Department of Commerce. This body had the right of veto. The idea was to prevent the US from leaving modern technologies that could be used for military purposes. The Department of Commerce has repeatedly exercised veto power over contracts in the aviation industry. For example, for the sale of General Electric CF6-50 engines for CCCP for Il-86 aircraft.
On December 11, 1978, a final cooperation agreement was signed between Piper and WSK PZL-Mielec. At WSK PZL-Mielec, the production of parts for the Piper company was undertaken, obtaining in return the documentation of this aircraft, with the right to serial production and sale on Eastern Markets. The contract gave the right to develop the structure.
At WSK PZL-Mielec, after research and development work on the Dromader agricultural aircraft family, a new team was appointed to work on the M-20 Mewa aircraft. The team consisted of young, talented engineers who already had a lot of experience. The leading constructor was mgr inż. Krzysztof Piwek, graduate of the Faculty of Power and Aeronautical Engineering at the Warsaw University of Technology. It should be noted that the M-20 Mewa aircraft did not become a typical license for the PA-34 Seneca II aircraft. The obvious change was the installation of PZL-Franklin engines, which in fact turned out to be easy.
A much more difficult task was to adapt the materials already produced in Poland to the structure of the airframe. It seemed to be an easy task. But only for the layman. Polish duralumin alloys differed in composition from American ones, and thus in physical properties. In addition, we produced sheets in metric thicknesses, and the Americans in inch thicknesses. The differences seem small, but for an airplane that weighs 2,155 kg in total, these differences can reach many kilograms. In addition, thicker sheet metal does not mean greater strength. Therefore, the development team had to recreate all the loads, the entire test program and go through the certification process again. It was a lot of extra work for the constructors. However, as a result, materials produced by Polish steelworks could be safely used. Also in the avionics equipment, components manufactured by the Polish Aviation Industry were used.
In the first half of 1978, documentation of the Polish version was developed in Mielec and the assembly of the prototype began. The first M-20 Mewa aircraft was marked M-20-00, PZL M-20 Mewa No. 1AHP 01-01 registration SP-PKA. It was assembled from components supplied by the licensor in October 1978. The aircraft made its first flight on July 25, 1979 (Wednesday). The pilot was Mr. Tadeusz Pakuła. The aircraft could use 2 x PZL-Franklin 6A-350C or 2 x Teledyne Continental TSIO/LTSIO-360-KB engines as a drive.
A few weeks later, the first serial aircraft PZL M-20-01 No. 1AH 002-02, registration SP-PKE, was flown. In this and the next prototype, components supplied from the USA were also used. The next prototype, marked M-20-01, produced in Poland, was flown on September 22, 1982. Only the fourth copy was produced entirely from Polish components. In the next prototype (M-20-02), the electrical installation and power supply to the drive unit were improved. Its first flight took place on October 10, 1985.
During this period, the entire M-20 Mewa program was questioned for political and military reasons. Moscow did not like Polish contacts with the USA. It was also impossible to find a sensible use for the M-20 for the needs of the armed forces. Let us remind you that almost the entire Polish Aviation Industry worked for the needs of the Soviets at that time.
At that time in Poland, due to the wear and tear of the old L-200 Morava aircraft, there was a shortage of medical aircraft. Production M-20 aircraft could fill this gap.
Due to the priority given by PZL Mielec to work on military aircraft, namely the PZL I-22 Iryda and problems with the serial production of the PZL-Franklin engine, the development of the M-20-03 version with Teledyne Continental TSIO/LTSIO-360 engines was undertaken. -KB, which is the equivalent of the PA-34-220T Seneca III aircraft. The prototype flew on October 13, 1988. Problems with the serial production of PZL-Franklin engines also affected the condition of the M-20 Mewa aircraft. (The issue of problems with PZL-Franklin engines needs to be supplemented).
In the summer of 1989, the serial aircraft of the M-20-03 version made a acquisition rally through the Middle East to India, where it flew over the Himalayas.
In 1993, another version of the aircraft was developed, marked M-20-04, with an increased take-off weight of 2,155 kg. Unfortunately, production did not start. In 1993, the M-20 Mewa aircraft was awarded the "Teraz Polska" emblem. By 1993, 18 aircraft had been built. At that time, the Masonic Governments in the Republic of Poland were already liquidating the Polish Aviation Industry.
Around 1995, one of the M-20 units at WSK PZL Rzeszów was re-adapted to PZL-Franklin engines, the production of which was launched at this factory. At that time, the leading constructor of the aircraft was mgr inż. Mieczyslaw Wojtkowski.
According to the data, until 2002, in two production series, a total of 20 (other sources say 23) PZL M-20 Mewa were produced.
Continued in the next chapter.
Written by Karol Placha Hetman