F+W C-3605 Schlepp – Alpine Anteater

The unmistakeable C-3605 seen at Pardubice, Czech Republic in 2018.

The Nose of Neutrality 

With it’s long nose, triple fin tail and substantial size for a single engine aircraft; the F+W C-3605 Schlepp (Tug) is a distinctive and imposing presence wherever it makes an appearance. Its shape turns heads while its unusual origins and rarity generate many questions from those not familiar with the type.

All those design features that make the C-3605 an eye catching, if ungainly, sight on the ground belie a machine of impressive agility and performance in the air.

The C-3605 was the final version of the C-36, a pre Second World War design for a multi-purpose combat aircraft by the Swiss state owned Federal Construction Works (EKW).

The piston engined EKW C-3603 version entered Swiss military service in 1942 and was used alongside Swiss license built versions of the Morane-Saulnier M.S. 406 fighter to defend the neutrality of Swiss airspace suring the Second World War.

Through the 1940 to 1943 period, the aviation arm of EKW was moved from Thun to Emmen and renamed Federal Aviation Works (F+W).

Today the F+W legacy is in the hands of the RUAG Group.

Another angle on the C-3605 at Pardubice in 2018.

The Life of the “Anteater” 

In the late 1940s, after being replaced in their combat capacity by the DeHavilland Vampire, a number of C-3603 aircraft were converted to target tug configuration by F+W. The converted aircraft were redesignated C-3603-1.

In the mid 1960s, with the WWII era Hispano-Suiza piston engines that powered the C-3603-1 reaching the end of their usable lives, studies were carried out on how best to maintain the target tug role in the Swiss air force.

By the late 1960s, it was determined that the airframes of the C-3603-1 fleet had at least another ten years of usable life in them and that the most cost effective solution would be to re-engine them so that they could carry on the target tug duties themselves.

The decision was made to convert a number of C-3603-1 aircraft to turboprop power via the American made Lycoming T53 engine. The conversion process would be overseen by F+W’s chief engineer, Jean Pierre Weibel (1934-2013), and the first converted prototype took to the air for the first time in August of 1968.

The most prominent aspect of the conversion was the nearly two metre nose extension that led to the new variant, designated C-3605, to be given the nickname “Alpine Anteater”. The extension was required in order to maintain the aircraft’s centre of gravity; as the new Lycoming engine was lighter than the old Hispano-Suiza engine by an order of nearly 160 kilograms, physics demanded that it be placed in a position much further forward than the old engine to maintain the aircraft’s balance and stability.

Flight testing revealed that a third vetical tail fin would give the C-3605 improved stability over the two vertical fins of earlier variants in the C-36 family.

With the new nose, third tail fin and a number of cockpit modifications, the C-3605 entered Swiss military service in 1971. A total of 23 aircraft were converted to the C-3605 standard between 1971 and 1973 including two as dual control flight trainers.

The aircraft did very well for itself in military service, staying on charge much longer than the ten years projected for the airframes in the late 1960s when the conversion was ordered. Ultimately, the C-3605 served until 1987 when it was replaced by a target tug variation of the Pilatus PC-9. After retirement, the bulk of the C-3605 fleet was auctioned off in late 1987.

In military service, the C-3605 was appreciated for its good handling qualities, stability, agility and a wide range of speeds that allowed it to operate effectively from speeds lower than 150 kph to speeds exceeding  550 kph.

View of the “Anteater” in flight at Pardubice in 2018.

The “Anteater” Today

Given that only around two dozen aircraft were converted to C-3605 status, the machine has done reasonably well for itself in retirement.

A number are known to be preserved in American, German and Swiss museums.

The impressive performance qualities that made it popular in military service have followed it into retirement and ensured that enough interest exists to keep the C-3605 flying.  Its unorthodox appearance ensures that it turns heads and generates interest in airshow crowds wherever it goes.

In recent years, the world has known only two airworthy examples of the type. Both aircraft were on the Swiss civil register and made appearances at European airshows. As late as Autumn of 2020, both aircraft were up for sale.

According to some references, some examples of the type currently in museums could be made airworthy again. As such, time will tell if the world will see more of the “Anteater” in the sky in the future.

Further Reading

This link will take you to an article about the C-3605 at the website of the online aviation magazine, Afterburner.

This link will take you to the C-3605 page of Yak UK, a British organization which used to keep a C-3605 airworthy on the British civil register. While their “Anteater” has since been sold on, there is still a good amount of information on the type there.