The Mighty Hercules

pickledwings:

Here’s a lovely write up about an encounter with an aircraft type quite close to my heart, the C-130 Hercules.

Originally posted on Keep Calm and Remember:

This post is about the incredible C-130 Hercules military aircraft- but don’t worry, it’s not going to be a flavourless list of specifications and figures. Although I’d probably find such a list interesting, I’ll restrain myself! Instead, this post will focus on a fortuitous day in June 2012; when I saw a Hercules up close, and most unexpectedly!

I’d just landed at London International Airport (located in Ontario’s London), where I was picked up by my grandparents. It’s about a half-hour drive through verdant countryside to my grandparents’ house, and as we drove my eyes (as usual) kept wandering to the sky. I’m always on the lookout for airplanes… well, my attention was rewarded that day by the sight of a mammoth military plane in the sky! At once, I recognized it to be a C-130 Hercules; the transport mainstay of the Royal Canadian Air Force for the past fifty years!…

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Schneider Grunau Baby – A Soaring Sensation

A Zlín 24 Krajánek, the Czechoslovak built version of the Grunau Baby IIb, seen at Prague in 2014
A Zlín 24 Krajánek, the Czechoslovak built version of the Grunau Baby IIb, seen at Prague in 2014

A Titan of the Thermals

The interwar period saw a complete change in how people viewed aviation; members of the general public aspired to be part of what was once seen as the exclusive territory of the elite or eccentric. The aircraft was seen to have a practicality and mass appeal not perceived prior to the First World War. It was a golden age that saw tremendous development in a wide range of aviation related disciplines.

This period was a true heyday for gliders, particularly in Germany. The conditions of the armistice which formally ended the First World War forbade powered flight in Germany, but made an exemption for soaring activities. Not surprisingly, air minded Germans flocked to the activity in droves and many key developments in glider design were pioneered by German designers in this period. One such designer was Edmund Schneider (1901-1968), whose Grunau Baby design of 1931 was a watershed event that would prove wildly popular worldwide and influence the design of successive generations of sailplanes.

While gliding was immensely popular in the interwar period, it was an expensive pastime in a period where not everyone who wished to get involved had the financial means to do so without great sacrifice. It was also a period of great experimentation and risk, with many gliders being primitive home built types which often only barely if at all met airworthiness standards of the day or were built primarily for high performance competition. For many pilots, whose main desire was simply to fly, a different sort of aircraft was needed.

Seeing the obvious need for affordability, safety and docile handling characteristics; Edmund Schneider set about creating a solution by downsizing and simplifying the design of one of his company’s existing glider types. The resulting aircraft, the Grunau Baby, was an affordable glider which could be build easily from plans and was safe and responsive enough to become the standard training glider for many soaring clubs worldwide during the interwar period. The Baby put emphasis on basic flight training and cross-country flying and struck a balance of price to performance that satisfied soaring clubs around the globe.

A Zlín 24 showing the high  degree of wood construction which was a hallmark of the Grunau Baby family.
A Zlín 24 showing the high degree of wood construction which was a hallmark of the Grunau Baby family.

A Revolution of Least Risk

Schneider’s company was based in Grunau, today known as Jezow Sudecki, in Poland. Geographically, the region was ideal for soaring and attracted many accomplished glider pilots so Schneider had optimal conditions to perfect his designs and access to experienced pilots to test fly them.

The prototype Baby glider was a modification of Schneider’s existing ESG 31 sailplane, but with a new wing of smaller size and more refined design of elliptical plan form with large ailerons to give greater responsiveness. The Baby inherited the older glider’s deep and narrow fuselage of hexagonal cross section which had already been proven to work well. The Baby I was developed through the winter of 1930 and took to the air for the first time in 1931.

The Baby incorporated a great deal of wood in its design, possessing a wood frame fuselage covered in wood sheeting and the forward sections of the wing and horizontal tail constructed in a similar manner. The use of so much wood assured the aircraft would be of strong construction, affordable and easy to build from plans and local materials. Indeed, the Baby was built in at least 20 countries under license both before and after the Second World War; it could be built either in a factory setting or by private individuals who possessed the skills and means to do so.

The first major revision to the Baby came in 1932 when, as the result of a fatal crash of a different Schneider sailplane design, Schneider ordered extensive revisions to the Baby for safety reasons; these revisions resulted in the Baby II. The addition of air brakes on the wings created the Baby IIb, widely considered the definitive version of the Baby family. The Baby II and IIb were immediately popular on a wide scale and more than 1,000 had been built by the time the Second World War began. The German war effort saw production of the Baby increased tremendously to meet the demand for a basic flight trainer for potential Luftwaffe pilots.

The Baby's elliptical wing with large ailerons seen to good advantage.
The Baby’s elliptical wing with large ailerons seen to good advantage.

Life After War and Enduring Influence

Unlike the armistice conditions of the First World War, those which formally ended the Second World War made no special exceptions for gliders when forbidding aviation activities in Germany. Edmund Schneider fled from Poland and, after holding a few non aviation related jobs in West Germany, endeavored to move his family abroad.

While he initially considered India, his attention was caught by news of attempts to create organised gliding clubs and build gliders in Australia. After making contact, financial assistance was given for Schneider and his eldest son to travel to Australia to build and advise fledgling Australian companies on how to build gliders.

Schneider spent the 1950s in Australia before returning to Germany in 1960. During his time in Australia, he further refined the Baby to, among other things, include a fully enclosed cockpit. Such refinements created the Baby III and Baby IV.

Many aspects of the Baby set new standards for glider design and helped to define favorable qualities in future generations of sailplanes. Perhaps the most significant lessons taken from the Baby family are to do with fuselage design as they showed how critical it was to reduce the fuselage cross section behind the wing to reduce the effects of airflow turbulence generated by the cockpit area.

Keeping the construction and assembly aspects of the Baby relatively simple also contributed much to the safety of gliders and many of the Baby’s safety aspects have been included and refined in later glider types.

A Zlín 24 performing at Prague in 2014.
A Zlín 24 performing at Prague in 2014.

The Baby Today

The total worldwide production of the Baby family is open to conjecture, but most sources put the total between 5,000 and 6,000 aircraft. Given such figures, it’s hardly surprising that several Grunau Babies remain airworthy in the hands of enthusiasts as vintage aircraft. In fact, enough are still airworthy that regular gliding meets of Baby owners can be held.

Jezow Sudecki remains an important hub of gliding activity to the present day and serves as home for The Glider Factory, the descendant company of Edmund Schneider’s pre war operations.

Several Babies are preserved in museums around the world and with several still flying, you probably have a good chance of getting up close to one if you’re in the right place at the right time.

Learning More

While a bit dated in places, this is a very good site to visit for information related to the Baby’s history, surviving examples and Edmund Schneider himself:

http://www.grunaubaby.nl/index.htm

This is the home page of The Glider Factory; here you can find some historical information about the company and also their current activities:

http://www.szdjezow.com.pl/index_eng.html

When Lions Roar – A Good Read and a Good Cause

The Winged Lion Monument, unveiled in Prague in 2014, is the official thanks from the British expatriate communities of the Czech Republic and Slovakia to the approximately 2500 Czechoslovaks who bolstered the Royal Air Force ranks in the Second World War.
The Winged Lion Monument, unveiled in Prague in 2014, is the official thanks from the British expatriate communities of the Czech Republic and Slovakia to the approximately 2500 Czechoslovaks who bolstered the Royal Air Force ranks in the Second World War.

A Companion to the Lion

In 2014, after much protracted effort, the desire of the British expatriate communities of the Czech Republic and Slovakia create a permanent symbol of their gratitude to the many Czech and Slovak airmen who served in the Royal Air Force during World War Two came to fruition with the unveiling of the bronze “Winged Lion” monument near Prague’s city centre.

In August of 2014, a booklet was published in conjunction with the monument unveiling. Entitled “When Lions Roar”, it was written by Nicholas Watson and is marketed as: “A brief history of the some 2,500 Czechoslovak airmen who fought with the RAF during World War II.”

Very recently, I received my copy and read it in a single sitting.

A Story that Needs Telling

This is a story that, until the fall of Socialism in 1989, many Czechs and Slovaks had no knowledge of. This was because the Socialist regime was supporting the idea that Czechoslovakia was liberated exclusively by the Soviets. Anyone who could prove that was a lie, such as the airmen themselves, was deemed a threat to the state and marginalized or imprisoned. In short, the Socialist regime made a concerted effort to erase the airmen and their contribution to the war effort from history as far as the Czechoslovak populace was concerned.

At a time when the remaining few Czechs and Slovaks who fought in the RAF are in their twilight years, theirs is a story that must be told.

Even at a modest length of 81 pages, this book does a very good job of summarizing the experiences of the Czechoslovak airmen from the moment the Munich Agreement of 1938 saw them forced to hand over their airfields and equipment to German occupying forces to the humiliating treatment they were subjected to by the Czechoslovak Socialist regime when they returned home after the war.

Nearly as soon as German forces started taking control of airfields, Czechoslovak airmen began trying to escape to friendly countries. First to Poland, then to France and then to Great Britain after Poland and France had fallen. The book does a good job of showing how complicated and risky it was for them to even simply cross into Poland much less to points further away. The trip they had to make to get to France was particularly complex and anything but direct.

The book then moves on to the formation of the four fully Czechoslovak units, three fighter and one bomber, and the experiences of Czechoslovak personnel in the RAF. This section Contains profiles of some of the more notable airmen and missions of the conflict, from the initial 88 who took part in the Battle of Britain to the total of roughly 2,500 who served in the RAF throughout the war.

Finally, the book takes the reader to an overview of the harsh and humiliating treatment the airmen and their families received upon returning to their homeland after the war. They were marginalized and watched very closely by agents of the StB, the secret police; those who had returned with foreign wives came under particularly close watch. This section also highlights the extremely limited work prospects the airmen had open to them, mainly hard manual work on farms or in mines and foundries.

The final section also touches upon escape attempts from Czechoslovakia made by the former airmen in the post war period, including a quite complex multiple hijacking of three Czechoslovak Airlines flights in one day. Escaping post war Socialist Czechoslovakia was every bit as harrowing and risky as escaping German occupied Czechoslovakia, the only thing that had changed was that it was the StB and not the SS that had to be evaded.

The book is rounded out by a short appendix that gives brief histories of the four Czechoslovak RAF squadrons, plus an RAF squadron that had a very high number of Czechoslovak airmen in it and was eventually adopted as a Czechoslovak unit.

A Small Package with Substance

While small, this book was clearly designed for broad appeal. The writing style is straightforward and accessible, there is enough information to satisfy those who possess only a general interest and enough to serve as a primer on the subject for those wishing to learn more.

I recommend it to anyone with an interest in either military history or this particular chapter in Czech and Slovak history.

Buying the Book and Helping a Good Cause

“When Lions Roar” can be purchased online from the Shakespeare & Sons bookshop in Prague:

http://www.shakes.cz/book/273581

At the beginning of the book, there is a page suggesting a donation to the Sue Ryder charity in Prague if you wish to lend support to the cause of remembering this particular group of veterans.

The Sue Ryder charity runs a home for the elderly in Prague and has close ties with the Royal Air Force to help veterans and their widows. You can find more information about the Prague operations of Sue Ryder at their website:

http://www.sue-ryder.cz/en

A Couple of Good Reads for you to Check Out

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While deciding on the subject of my next blog entry, I’ll use this week’s spot to recommend a couple of books I’ve read recently that I quite enjoyed and think you might enjoy too:

Lettice Curtis – Her Autobiography

Lettice Curtis (1916-2014) dedicated her life to flight and, as such, had many stories to tell. She spent the Second World War in the Air Transport Auxiliary, a group of civilian pilots tasked with ferrying RAF aircraft around Britain to operational squadrons. Her stories from her time in the ATA highlight the high risk nature of the work and give a good deal of insight into the differences in flying the various aircraft types that became legends in RAF service during the conflict.

The book follows her post war life working as a pilot for Fairey Aviation and as a flying instructor.

A truly engaging book about a remarkable life.

http://www.wingleader.co.uk/shop/lettice-curtis-her-autobiography/

An Astronaut’s Guide to Life on Earth

This is the first book written by Chris Hadfield, a former Canadian Armed Forces fighter pilot and astronaut; a very enjoyable first effort it is.

The book follows Hadfield from his earliest childhood dreams of becoming an astronaut to the reality of him becoming one and how he has been able to apply all of the training he received in becoming an astronaut to his everyday life on Earth.

Where this book really shines is in giving an insight into the life of an astronaut and the realities of it. It certainly is a very different world than the movies would have you believe and the kind of personality needed to be a successful astronaut is certainly not what one might expect.

http://chrishadfield.ca/books/

Praga Air Baby – Sky Bound Sports Car

A Swiss registered E.114M displaying at Prague, Czech Republic in 2014.
A Swiss registered E.114M displaying at Prague, Czech Republic in 2014.

Feeding A Hunger

The interwar period saw an increasing interest in aviation among the public of many nations around the world. It was in this period that general aviation was born; the First World War had demonstrated quite clearly that the airplane could be practical rather than simply the plaything of eccentric dreamers, as early aviators were often considered to be.

The Praga company, founded in 1907 and still operating today, merged with Czechoslovak engineering giant ČKD in 1929 and produced a selection of aircraft through the 1930s. The E.114 Air Baby, which was aimed at the growing sport touring aircraft market, took to the air for the first time in Autumn of 1934 and would see production both before and after the Second World War.

The Air Baby, so named for its very light weight, spent most of its life firmly in the civil aviation sector and set many records for distance and speed in its class as well as taking victory in a number of international air rallies.

E.114M at Prague in 2014.
E.114M at Prague in 2014.

Engineering Efficiency

The E.114 was a very clean, efficient and modern design for its time. In a period where open cockpit biplanes with wire braced, fabric covered wings and fuselages were still in abundance; the Air Baby was a monoplane of all wood, internally braced construction with a fully enclosed cockpit. It also had a single piece wing and accommodated two people in a side by side arrangement.

The weight savings and aerodynamic benefits that the Air Baby’s all wood construction and internally braced wing produced allowed the aircraft to be powered by a substantially smaller and less powerful engine than many other aircraft of its class could use. The Praga B series engines fitted to the E.114B versions were two cylinder engines of roughly 40 horsepower; though low on power, the B series engines were noted for low fuel consumption.

After a series of demonstrations across Europe and being shown at the 1934 Paris air salon, enough interest had been generated in the Air Baby that a license for production in the United Kingdom was granted. A total of around 40 E.114B aircraft were constructed by F. Hills & Sons Ltd. of Manchester along with approximately 135 Praga B2 engines built by Jowett Cars Ltd. of Bradford. The British produced aircraft were marketed under the name Hillson Praga. Several were used by a flight school in Manchester while several others reached other points in the UK or were exported.

Other interwar developments of the E.114 included the E.114D, which was powered by a four cylinder engine, as well as the E.115 and E.117 which both featured significant revisions to the wing and fuselage design. Additionally, a single example of the radial engined E.214 variant was built.

E.114M at Prague in 2014.
E.114M at Prague in 2014.

While the German occupation of Czechoslovakia interrupted Air Baby production, the aircraft had already left a big mark on the international aviation landscape. Among the aircraft’s interwar accomplishments for its class were:

A world record of 1020 kilometers flying without landing.

Flying non-stop from Prague to Constantinople, a distance of 1560 Kilometers.

A world record flight from Prague to Moscow, 1680 kilometers, in 15 and a half hours.

An English record flight of 14,722 kilometers between London and Cape town in 16 days.

In its E.115 variation, it set two world records for speed in a straight line and new world records for altitude in both one person and two person categories.

E.114M at Prague in 2014.
E.114M at Prague in 2014.

Life After War

In 1946, Praga reopened the Air baby production line with the E.114D version and its four cylinder Praga D engine. By 1947, the E.114M version with a more powerful four cylinder Walter Mikron engine was introduced as the last member of the aircraft family.

While the bulk of pre war Air Babies, both Praga and Hillson versions, did not survive the war; post war versions proved popular as touring and training as well as glider tug aircraft in several countries around Europe.

Total pre and post war production came to around 275 airframes . The aircraft enjoyed export success to such countries as: Algeria, Australia, Finland, France, Germany, Iran, Italy, Romania and Switzerland.

Through the 1960s, with Praga having turned its attentions away from aviation as well as superior aircraft being introduced, the Air Baby faded from favour. Through the late 1980s and the 1990s, none were airworthy.

Happily, over a six year period spanning 2003 to 2009, an E.114M was restored to airworthy condition and placed on the Swiss civil register as HB-UAF. At the time of writing, it appears to be the only airworthy example of the type in the world.

A partially reconstructed E.114B showing the distinctly different nose contour created by the Praga B2 engine. Prague, 2014.
A partially reconstructed E.114B showing the distinctly different nose contour created by the Praga B2 engine. Prague, 2014.

Learning More

The Air Baby has not fared so well in retirement and your chances of seeing one are slim indeed if you don’t travel to Europe. Of the 275 or so built, the only three examples known to survive intact are to be found there.

The aforementioned HB-UAF resides in Switzerland though does make appearances at shows around Europe.

Another former Swiss E.114M, HB-UAD, is now under Czech ownership and in the process of being reconstructed to E.114B status with an original Praga B2 engine. As it is on the Czech civil register, presumably the intent is to return it to the air at some point.

The third surviving Air Baby is an E.114D which is on display in the Kbely Air Museum in Prague, Czech Republic. It is not airworthy.

The following two links will take you to pages relating to the E.114B currently under reconstruction in the Czech Republic. The translation is a bit rough in spots, but there’s quite a few interesting pictures of the reconstruction process:

http://translate.google.cz/translate?hl=en&sl=cs&u=http://avia.vyrobce.cz/doc/e114stavba.htm&prev=search

http://translate.google.cz/translate?hl=en&sl=cs&u=http://avia.vyrobce.cz/doc/e114his.htm&prev=search

This link will take you to a brief overview of HB-UAF:

http://translate.google.cz/translate?hl=en&sl=de&u=http://www.gost.ch/index.php/gost-flugzeuge/oldtimer-a-andere/47-hb-uaf-praga-baby&prev=search

Saab 37 Viggen – Nordic Thunder

The Swedish Air Force Historic Flight's AJS 37 Viggen seen at Ostrava, Czech Republic in 2014
The Swedish Air Force Historic Flight’s AJS 37 Viggen seen at Ostrava, Czech Republic in 2014

Hammer of the Gods

First flown in February of 1967 and entering service with the Swedish air force in 1971, the Saab 37 Viggen cut such a distinctive shape in the sky with its delta wing and canard fore-plane arrangement that for nearly four decades it was an unmistakable symbol of Saab’s skill as an aircraft manufacturer and Sweden’s ability to protect its sovereignty in a visible and credible manner.

Saab’s model 35 Draken, which had preceded the Viggen, caught the aviation world’s attention and left no doubt that Saab were capable of competing with larger players in the field and were certainly not afraid of pushing boundaries. The Viggen further underlined these facts and showed that Saab were not about to rest on their laurels.

The name Viggen, generally translated simply as “Thunderbolt”, was taken from Norse mythology and is quite specifically connected to the thunder created by the god Thor’s hammer. A fitting name for a truly thunderous and imposing machine.

Let’s spend some time with one of Saab’s most recognizable products:

AJS 37 Viggen at Ostrava in 2014. Showing the Viggen's delta wing and canard design.
AJS 37 Viggen at Ostrava in 2014. Showing the Viggen’s delta wing and canard design.

A Revolutionary Replacement

The catalyst for creating the Viggen was the need for a multi role aircraft which could replace Saab’s model 32 Lansen in the attack role and, eventually, the model 35 Draken in the fighter role. Studies to determine the form of what would become the Viggen started in the early 1950s with the final design approved in 1962 and construction of the prototype started in 1964.

The service specifications for the new aircraft were very demanding ones specific to Sweden’s unique defensive doctrines at the time. This included the ability to operate from remote locations, away from established bases, using sections of highway as airstrips. Additionally, the aircraft had to be easily serviced by a minimal ground crew team that could be largely composed of conscripts and reservists with minimal training.

The Viggen also had to function as part of Sweden’s unique Stril 60 defensive network, be able to be refueled and rearmed in a maximum of ten minutes between missions, have mach 1 performance at low altitude and Mach 2 performance at high altitude.

A closer view of the Viggen's canard fore-plane.
A closer view of the Viggen’s canard fore-plane.

Saab settled on the distinctive delta wing and canard design to best address the flying performance stipulated by the air force. The canards made high speed flight at low altitudes smoother as well as guiding the airflow over the main wings in such a way as to increase lift, improve low speed stability and shorten take off and landing distances. The Viggen was the worlds first serial produced aircraft to feature canards as a standard design aspect.

Another first associated with the Viggen was to be found internally; it was the first European aircraft to feature a computer with integrated circuits as standard equipment. It was decided very early on to make the Viggen a single seat aircraft; The computer Saab developed to do away with a human navigator and weapons operator in the Viggen, known as the CK37, was a much more capable and maintainable system than the bulky analog flight computers of the day and proved that complex fast jets could be operated by a pilot alone.

Other distinctive aspects of the Viggen’s design included a hinge at the base of the tail fin to allow it to be folded down for storage in the many hangars the Swedish military had carved into mountainsides around the country and a thrust deflection system which could redirect the engine exhaust forward to significantly shorten landing length.

An SF 37 variant preserved at the Kbely Air Museum in Prague, Czech Republic in 2014.
An SF 37 variant preserved at the Kbely Air Museum in Prague, Czech Republic in 2014.

Foreign Flavours

Many sources state that Saab benefited from access to American data and resources when developing the Viggen; however, many of those same sources are not particularly clear on exactly what Saab was provided with from America.

What is for certain is that there was some exchange of information between Saab and American companies, Texas Instruments and Fairchild, while developing the CK37 computer. Both American companies were developing integrated circuit computers in the late 50s for the same goal as Saab had; a computer that would allow a single pilot to operate a complex jet aircraft.

As with their previous aircraft, Saab looked abroad for an engine to power the Viggen. They favoured the emerging turbofan engine technology to existing turbojets as it balanced the power of the turbojet with better fuel economy.

At first, Saab planned for the Pratt & Whitney TF30 as the Viggen’s power source but it would not be ready in time. Saab then looked to the Rolls Royce Medway from Great Britain; the Medway, however, was cancelled when the British aircraft it was intended to power was also cancelled.

The Pratt & Whitney JT8D engine, an airliner engine used in the Boeing 727 and Douglas DC-9 among others, was ultimately chosen for the Viggen and license built in Sweden as the RM8A and RM8B. The engine was married to a Swedish designed afterburner section and easily pushed the aircraft to the Mach 2 speeds required.

SF 37 preserved at Prague in 2014.
SF 37 preserved at Prague in 2014.

Worthy of note in regards to the RM8 engine is that many sources cite American imposed export restrictions on it as the reason the Viggen was not successful on the export market. However, this is something of an overstatement and oversimplification.

Several sources suggest that the export restrictions were the primary reason why the Viggen was not purchased by Belgium, Denmark, Norway or the Netherlands. All four countries gave consideration to the Viggen as a possible replacement for their Lockheed F-104 fleets in the early 1970s. However, the Viggen had the disadvantage of being an outsider in the competition for the new fighter in Europe as its competitors were all newer designs from NATO countries. As it was, by 1975, all four countries opted to purchase the General Dynamics F-16 from America. It was a decision that was made before the trade restriction was placed on the RM8.

The restrictions were imposed in 1978 when India was looking for a new strike aircraft. America blockaded the sale of the Viggen to India by refusing to issue an export license for the engine, this action was in keeping with arms embargoes that both America and Britain had placed on India after the 1965 India-Pakistan War. This forced India to select the Anglo-French Sepecat Jaguar instead.

With or without the trade restrictions, the Viggen never stood a chance in India. Those who were promoting it were politicians and business types out for personal gain while the air force themselves were adamant that the new aircraft be of two engined design.

All of this aside, Saab military jets of the Cold War era did not have a history of great export success. They were designed with Specifically Swedish needs at the forefront; many of those needs, like compatibility with the Stril network, were quite irrelevant to any other nation and had to be removed and replaced for export purposes. In the Cold War period, Sweden was not the nation to buy from if one wanted to purchase largely “Off the shelf” equipment.

An AJS 37 ascending from an very short take off roll at Ostrava in 2014.
An AJS 37 ascending from an very short take off roll at Ostrava in 2014.

The Viggen in Service

Though the Viggen never served any nation other than Sweden, it was a very respected machine outside the borders of its homeland throughout its nearly 40 year service career. From standpoints of serviceability, mission readiness and deployability; the Viggen was considered one of the most capable and potent combat jets in Western Europe for many years.

Built in five major variants, the Viggen served Sweden well in a variety of roles.

The first of the Viggens into service was the AJ 37, the strike fighter variant. From the same basic airframe, Saab also created the SH 37 which was optimized for maritime strike and reconnaissance and the SF 37 reconnaissance version.

The SH 37 retained the AJ 37’s radar and thus its ability to carry the full range of both guided and unguided weapons as well as a variety of camera and electronic gear in pods carried externally. By contrast, the SF 37 did away with the radar in favour of a camera and sensor package in the nose; consequently, the SF 37 did not possess the ability to carry and operate much of the AJ 37’s arsenal beyond infrared guided air to air missiles for self defense and unguided rocket pods.

Through the years, the AJ, SH and SF variants were subject to upgrades including a particularly extensive electronics upgrade in the early 90s. Aircraft upgraded in that program were re-designated as AJS, AJSH and AJSF versions.

The AJ 37 airframe was also used to create the two seat SK 37 training aircraft. To make room for the second seat, the SK 37 had reduced internal fuel volume, electronics simplified and the radar removed. Late in the Viggen’s service career, ten SK 37s were refitted for electronic warfare training and designated SK 37E. The SK 37E was the last Viggen variant in active service when it was retired in 2007.

The late 1970s saw the development of the JA 37, the air to air specialist of the Viggen family. Created as an interceptor first and formost, the JA 37 differed in many key ways from the earlier Viggen versions.

The JA 37 had a slightly lengthened fuselage which contained very modern avionics to replace the CK37 computer at the heart of earlier versions; it also featured the much more powerful RM8B engine. The extra power of the RM8B helped to create much different handling qualities between the JA version and earlier ones.

The JA version also featured a trio of large multi-function display screens in the cockpit; while this feature became standard in combat jets through the 80s and 90s, it was certainly not a common feature at the time the JA 37 debuted.

As with earlier versions, the JA was subject to a variety of upgrading programs over the years that created the JA 37C, 37D and 37DI sub variants.

The Swedish Air Force Historic Flight's AJS 37 coming in to land at Ostrava in 2014
The Swedish Air Force Historic Flight’s AJS 37 coming in to land at Ostrava in 2014

Thunder Echoes On

Retirement has been good to the Viggen. The distinctive and imposing shape that made it stand out among other aircraft during its active years was very helpful to the aircraft in ensuring that it would be in demand by museums. In fact, several Viggens were earmarked for specific museum collections even before they were retired.

Whether in Sweden or elsewhere in Europe, your chances of being able to visit a museum which possesses one of the 330 or so Viggens which were built is quite good.

Happily, a single AJS 37 has been kept in airworthy condition by the Swedish Air Force Historic Flight and visits airshows around Europe during the airshow season.

Learning More

This link will take you to Saab’s own web page about the Viggen where you can find a pdf version of a period marketing brochure about the aircraft:

http://www.saabgroup.com/en/About-Saab/Saab-History/Timeline/1960s/Saab-37-Viggen-AJJASFSHSK-37-in-the-Swedish-Air-Force/

This is a link to a pdf document about the development of the CK37 computer. It’s a bit dry in places, but does make clear what a breakthrough the CK37 was:

http://www.datasaab.se/Papers/Articles/Viggenck37.pdf

This is a quite insightful interview with a former Viggen pilot:

http://www.milavia.net/specials/iv_viggen/

This article is primarily about the Sepecat Jaguar in Indian air force service, but it does give a few paragraphs to the Viggen in the context of India:

http://www.bharat-rakshak.com/IAF/Aircraft/Current/607-Jaguar-25.html

Zlín Z-50 – Keeping a Hand on Glory

Z-50LS preserved at the Kbely Air Museum, Prague, Czech Republic in 2014.
Z-50LS preserved at the Kbely Air Museum, Prague, Czech Republic in 2014.

A Torch to Pass

Through the 1960s and early 1970s, international aerobatics competitions were largely ruled by successive members of the Zlín Tréner family of aircraft from Czechoslovakia. To this day; aircraft of this line remain popular for general aerobatics, training, glider tug and general aviation duties.

Zlín, at the government’s request, set about designing an all new aerobatics machine in the early 1970s that could carry on the winning tradition of the Tréner line before it. The new aircraft, which flew for the first time in 1975, was designated the Z-50 and it would spend the next decade or so successfully defending the company’s reputation in world class aerobatic competition.

The Z-50 made its competition debut at the 1976 World Aerobatic Championships and Czechoslovak pilots placed a very respectable third in solo competition and second in the team category. At the next championships in 1978, Czechoslovak flown Z-50s took first and third place in the solo category with a German flown Z-50 taking fourth place and Czechoslovakia winning the team competition.

The 1980 and 1982 World Aerobatic Championships were not so successful for the Z-50 pilots; however, Czechoslovak Z-50 pilots returned to winning form to take the 1984 and 1986 editions of the competition.

As it had been for the Tréner series of aircraft before them, the Z-50’s primary competition in aerobatics came from Yakovlev built machines.

The Z-50 was significant not just in competition; technologically, it represented a large change in aerobatic aircraft design methods and philosophies. Computers were used in refining and optimizing the design with great care being taken to ensure that the aircraft could meet the stringent requirements of international competition standards which included, among other requirements, that the aircraft be able to have a usable life span of 1,000 flight hours of demanding aerobatics.

The Zlín Z-50 story is one of passion, determination and pride. A skilled team took the aircraft from concept to first flight in a remarkably short two years. The end result was not only a winning machine, but also the world’s first serial produced aerobatics aircraft.

Four Z-50LX of the Flying Bulls team perform at Pardubice, Czech Republic in 2014.
Four Z-50LX of the Flying Bulls team perform at Pardubice, Czech Republic in 2014.

Hurdles to Clear

In spite of its relatively short developmental period, the designers of the Z-50 had a number of technical obstacles to overcome in order for the aircraft to be of world class competition quality.

The first hurdle was the question of how to power the Z-50. Unlike the Tréner, which had a Czech designed and built engine, there was no appropriate class of engine for the Z-50 available from domestic sources. Ultimately, a six cylinder engine from the American manufacturer Lycoming was chosen for the Z-50 and an “L” was placed in the name to reflect that.

The design team also had to strike a balance between airframe strength and saving weight. The Z-50 was of primarily metal construction for strength, but was designed to be dismantled into a few large components to save weight. The wing was built as a full span unit which the fuselage could be attached to by screws; the benefits of this type of wing design included the strength of a continuous wing spar, a reduction in materials used which translated into reduced weight and reduced time required for assembly and dis-assembly of the aircraft.

The weight savings continued in the design of the main landing gear legs which were made of a single, continuous strip of titanium. As with the wing, this resulted in a reduction of construction materials and assembly time.

Other design aspects of the Z-50 included the omission of landing flaps from the wings in favour of two part ailerons on each wing which covered the full wingspan and gave the aircraft an astounding rate of roll as well as a one piece cockpit canopy which gave the pilot an excellent all round view.

Z-50LS at Čáslav, Czech Republic in 2010.
Z-50LS at Čáslav, Czech Republic in 2010.

Dynasties in Parallel

From the inaugural World Aerobatic Championship competition in 1960 until the mid 1980s, the aircraft of the Zlín and Yakovlev companies were dominant forces. The various members of the Tréner series competed against various incarnations of the Yak-18 while the Z-50 found its contemporary in the Yak-50. With a very few exceptions across those two and a half decades, the championship was taken by either Zlín or Yakovlev machines.

While the Tréner and Yak-18 had much in common, primarily that they both started as training aircraft that had been reworked to bring their aerobatic qualities to the fore; the Z-50 and Yak-50 were very different beasts in every regard.

The Yak-50 was developed from the Yak-18 while the Z-50 was a clean sheet design bearing no design commonalities with its own forbear. As such, the Z-50 was a much more refined and modern aircraft in design than its Yakovlev counterpart and benefited from contemporary design philosophies and trends in a way the Yak-50 could not. In fact, after a series of accidents, the Yak-50 required a wing spar strengthening program to keep it not only competitive but airworthy at all.

Perhaps fittingly, Zlín and Yakovlev faded from top tier international aerobatics competition in the same manner they had entered: together. With the debut of The Sukhoi Su-26 from Russia and the French made Mudry CAP 230 in the mid and late 1980s, the writing was on the wall for Z-50, Yak-50 and their respective manufacturers as far as top level world aerobatic supremacy was concerned.

Z-50LX at Čáslav in 2010.
Z-50LX at Čáslav in 2010.

The “Fifty” Family

The Z-50, by virtue of being a serial produced aircraft, has its own pedigree that is worth a look. The “Fifty”, as many pilots refer to it, was built in five major variations over a span of nearly 20 years when production ended in the mid 1990s:

Z-50L
This was the first production version and fitted with a 260 horsepower Lycoming engine. 25 were made and several were converted to later LA and LS configurations.

Z-50LA
Upgraded variant introduced in 1980, most were converted from L versions.

Z-50LS
A more powerful variation, fitted with a 300 horsepower engine, introduced in 1982. over 30 of the LS version were built, several were conversions from earlier variants.

Z-50M
A total of five aircraft were made to the M standard. The M had a Czech made engine of 180 horsepower and was intended to replace the aging Z-526 Tréner version.

Z-50LX
The final variant of the family debuted in 1991. It was optimized for airshow performance and was fitted with additional internal fuel tanks as well as a smoke generating system.

Z-50LX of the Flying Bulls team at Pardubice in 2014.
Z-50LX of the Flying Bulls team at Pardubice in 2014.

The Show Goes On

Though its top tier competition days are well behind it, the Z-50 is still a very active flyer at the time of writing. Several of the type are active on flying registers around the world and can be found on aircraft sales websites.

It is still appreciated for its excellent aerobatics qualities and remains popular in some levels of competition, general aerobatics flying and airshow performances.

The Z-50 still has plenty to give as an exciting performer and doesn’t look set to have its wings permanently clipped anytime soon.

The following links make up a fascinating and exciting two part write up of a pilot’s journey to being certified to fly the Z-50. It gives a good overview of what it’s like to actually fly the Z-50 and gives an insightful comparison between the Z-50 and the two aircraft types the pilot passed through while training for the “Fifty”:

http://www.snap-and-roll.com/articles/others/item/627-how-do-you-get-started-flying-a-single-seat-aerobatic-plane-part-i.html

http://www.snap-and-roll.com/articles/others/item/647-how-do-you-get-started-flying-a-single-seat-aerobatic-plane-part-ii.html