Rotax

Rotax is the brand name for a range of internal combustion engines developed and manufactured by the Austrian company BRP-Rotax GmbH & Co KG<ref name="About">Template:Cite web</ref> (until 2016 BRP-Powertrain GmbH & Co. KG), in turn owned by the Canadian Bombardier Recreational Products (BRP). Under the Rotax brand, the company is one of the world's largest producers of light piston engines.<ref name="rotax_1995_96_janes_p690">Gunston, Bill: "Rotax", in "Austria", in "Aero Engines," in Jane's All the World's Aircraft, 1995-96, (1995), page 690, Template:ISBN, Coulsdon, Surrey, U.K.</ref>

Rotax four-stroke and advanced two-stroke engines are used in a wide variety of small land, sea and airborne vehicles. Bombardier Recreational Products use them in their own range of such vehicles.<ref name="brp">Template:Cite web</ref> Since the 1990s, Rotax has been the world's dominant supplier of engines for ultralight aircraft and light sport aircraft, and a major producer of engines for other light aircraft.<ref name="gunston">Gunston, W.; "World Encyclopaedia of Aero Engines", 4th Edition, Patrick Stephens Ltd, 1998, Page 170.</ref><ref name="rotax_912_diff_aopa_org">Busch, Mike: "Outside the Box: The Rotax 912 is delightfully different," 1 June 2017, AOPA Pilot, Aircraft Owners and Pilots Association, retrieved 29 June 2023</ref><ref name="deep_2022_02_18_flyingmag">Pimentel, Dan: "A Deep Dive into Rotax LSA Engines: Phil Lockwood provides insight on the most popular light sport engine," 18 February 2022, Flying, retrieved 29 June 2023</ref><ref name="troubleshooting_ultralightnews">"Troubleshooting the Rotax ultralight aircraft engines," Ultralight News, retrieved 29 June 2023</ref><ref name="baton_2022_12_19_kitplanes">Wanttaja, Ron: "Homebuilt Accidents: Passing the Engine Baton," 19 December 2022, Kitplanes, retrieved 29 June 2023</ref>

History

The company was founded in 1920 in Dresden, Saxony, Germany, as ROTAX-WERK AG, the name referring to the "rotanda axis" used in the 1906 bicycle freewheel patent by Friedrich Theodor Gottschalk (1858-1932). In 1930, Rotax was taken over by Fichtel & Sachs and transferred its operations, soon reduced to sales, to Schweinfurt, northern Bavaria, Germany. When this area came within reach of allied bombing in 1943, the engine production of Fichtel & Sachs was moved further south-east within the Greater German Reich, to Wels, Reichsgau Oberdonau, into the facilities of Reform-Werke Bauer & Co that had produced agricultural machines. To conceal this move, the Rotax name was used.Template:Fact

After the war, under US control, Reform-Werke Bauer resumed agricultural production in the Wels city center near the central station. Rotax was moved to nearby Gunskirchen in 1947, and ownership was transferred by the 1955 Austrian State Treaty to Austria. In 1959, the majority of Rotax shares were taken over<ref>Template:Cite web</ref> by the Vienna-based Lohner-Werke, a manufacturer of car and railway wagon bodies.Template:Fact

In 1970, Lohner-Rotax was bought by the Canadian Bombardier Inc. The former Bombardier branch, Bombardier Recreational Products, now an independent company, uses Rotax engines in its ground vehicles, personal water craft, and snowmobiles.<ref name="brp" />

Applications

Snowmobiles

The original application for Rotax engines was Ski-Doo snowmobiles from Bombardier Recreational Products including two-stroke and four-stroke, turbocharged and naturally aspirated, two- and three-cylinder models.<ref>Template:Cite web</ref>

Aircraft

Rotax is one of the world's principal suppliers of aircraft engines for ultralight aircraft, light aircraft and unmanned aerial vehicles.<ref name="rotax_1995_96_janes_p690" /> Between 1985 and 1995, 60,000 Rotax engines were sold for aircraft propulsion.<ref name="rotax_1995_96_janes_p690" /> In the light aircraft class, in 1998 Rotax outsold all other aero engine manufacturers combined.<ref name="gunston" /> Their four-stroke engines powered most U.S.-certified light sport aircraft when they first appeared around 2004.<ref name="rotax_912_diff_aopa_org" /> Over two decades later, Rotax engines remain the most popular line of engines for light sport and ultralight aircraft,<ref name="deep_2022_02_18_flyingmag" /><ref name="troubleshooting_ultralightnews" /> and the second-most-popular (after Lycoming Engines) for U.S. Experimental / Amateur-Built (E/A-B) aircraft.<ref name="baton_2022_12_19_kitplanes" />

Two-stroke aircraft engines

Rotax air-cooled, two-stroke engines began appearing on ultralight aircraft in the early 1980s, with a pair of single-cylinder, Template:Cvt Rotax 185s<ref name="burger_burr_2_p493">"Rotax," in "Engines" in Burger-Burr's Ultralight and Microlight Aircraft of the World, 2nd Ed., pages 493-495, (1985); Haynes; Somerset, England, U.K.; Template:ISBN</ref><ref name="burger_burr_2_p101">"Lazair Series III..." in "Ultraflight Sales," in "Canada" in Burger-Burr's Ultralight and Microlight Aircraft of the World, 2nd Ed., p.101 (1985); Haynes; Somerset, England, U.K.; Template:ISBN</ref> powering the single-seat Lazair ultralight by 1982.<ref name="burger_burr_2_p101">"Lazair Series III..." in "Ultraflight Sales," in "Canada" in Burger-Burr's Ultralight and Microlight Aircraft of the World, 2nd Ed., p.101 (1985); Haynes; Somerset, England, U.K.; Template:ISBN</ref> Soon, the Template:Cvt, single-cylinder Rotax 277<ref name="burger_burr_2_p493" /> became the most widely used engine powering U.S. ultralight aircraft (and remains, for many, the only Rotax engine they can use to adequately power the aircraft and still remain within the FAA-mandated weight limits for ultralight aircraft which can be operated without a pilot's license).<ref name="burger_burr_2_all">Burger, Alain-Yves and Norman Burr: Burger-Burr's Ultralight and Microlight Aircraft of the World, 2nd Ed., (1985); Haynes; Somerset, England, U.K.; Template:ISBN</ref>

Two-stroke Rotax model numbers approximated the engine's displacement (in cubic centimeters), and the first two digits (from the 277, on) are very roughly similar to the engine's horsepower (e.g.: The Rotax 447 engine displaces 437 cc, and is rated at Template:Cvt).<ref name="burger_burr_2_p493" />

Subsequent evolutions of the early designs included the two-cylinder, two-stroke Rotax 377, Rotax 447, and Rotax 503, all in production by 1985<ref name="burger_burr_2_p493" /> (the last of these, the 503, was discontinued in 2010-2011, by then the most popular engine it its class, and still widely used as of 2023).<ref name="affordable_2022_02_03_bydanjohnson">Johnson, Dan: "What’s Affordable in 2022? A New “503,” Wheeled-Carriages, and Two-Place PPGs," 3 February 2022, ByDanJohnson.com, retrieved 29 June 2023</ref> Later two-stroke designs included the Rotax 532 (circa 1984) and Rotax 582, both of which augmented the air-cooling with liquid-cooled cylinder heads.<ref name="burger_burr_2_p493" />

Most Rotax two-stroke engines were rated, recommended, or reported with a TBO (time between overhauls) of about 150-300 hours (compared to 1200-2000 hours for government-certified, conventional, four-stroke, light aircraft engines), though later models improved upon that some.<ref name="troubleshooting_ultralightnews_2">"Rotax air-cooled aircraft engine troubleshooting, Rotax 185, 277, 377, 503 troubleshooting reports, Volume 2," Ultralight News, retrieved 29 June 2023</ref>

Four-stroke aircraft engines

Moving towards more demanding aircraft applications, Rotax, by 1989, developed a four-stroke, four-cylinder, engine: the Rotax 912, with versions eventually ranging from Template:Cvt, followed by a turbocharged 115 horsepower Rotax 914.<ref name="rotax_912_diff_aopa_org" />

Rotax four-stroke engines differ from conventional four-stroke aircraft engines by their unusually small displacement for the amount of power -- compensated for by higher than normal rotational speed (over 5,000 rpm). To reduce propeller-shaft speeds to normal aircraft propeller rotational speeds, (around 2300-2400 rpm) the engines use a reduction gearbox.<ref name="rotax_912_diff_aopa_org" /> They are also designed to accept motor spirit, with up to 10% ethanol content.<ref name="equal_2011_05_06_aopa_org">Twombly, Ian J.: "Does light aircraft equal light maintenance?," 6 May 2011, AOPA Pilot, Aircraft Owners and Pilots Association, retrieved 29 June 2023</ref><ref name="concerns_2011_08_06_midwestflyer">Template:Cite web</ref>

These engines were initially given a 600-hour Time Before Overhaul (TBO), less than traditional light aircraft engines.<ref name="rotax_912_diff_aopa_org" /><ref name="guide_lightaircraftassn">"Rotax Service Interval Guide" (for the 912/914), ConAir Sports, via Light Aircraft Association (U.K.), retrieved 11 July 2023</ref><ref name="sb_912_005_rotax_1996_07_19">Template:Cite web</ref> But operational experience and modifications to address specific reliability issues over time gradually extended the TBO to 2,000 hours.<ref name="rotax_912_diff_aopa_org" /><ref name="guide_lightaircraftassn" /><ref name="sb_912_005_rotax_1996_07_19">Template:Cite web</ref><ref name="concerns_2011_08_06_midwestflyer" /> An independent 2022 statistical study of U.S. government accident data found that the Rotax 912 family had the lowest rate of failure of the six most common lines of engines used in registered Experimental/Amateur-Built (E/A-B) aircraft.<ref name="baton_2022_12_19_kitplanes" />

By 2014, Rotax had produced and sold 50,000 of 912/914 four-stroke engines.<ref name="rotax_912_diff_aopa_org" /> Later models increased power, with several variants of the 912 family, and a new Template:Cvt Rotax 915 iS.<ref name="rotax_912_diff_aopa_org" /><ref name="rotax_915is_aopa_org">Horne, Thomas A.: "Rotax dials up the power," 21 July 2015, AOPA Pilot, Aircraft Owners and Pilots Association, retrieved 29 June 2023</ref>

The Rotax four-stroke aircraft engine line immediately dominated the emerging category of U.S.-certified "Light Sport Aircraft" (LSAs), powering most of them.<ref name="deep_2022_02_18_flyingmag" /><ref name="affordable_2022_02_03_bydanjohnson" /> One general aviation industry media reporter found that 70-80% of the 66,000 aircraft he'd identified, worldwide, used Rotax four-stroke engines.<ref name="affordable_2022_02_03_bydanjohnson" /> The 912/914/915 series also powers larger certified aircraft, including the Diamond Katana, and the twin-engined Tecnam P2006T and Leza/Lockwood Aircam.<ref name="deep_2022_02_18_flyingmag" />

Motorcycles

The Can-Am division of Bombardier Inc. developed a line of motorcycles starting in 1971, powered by Rotax engines. The Can-Am motorcycle operation was outsourced to Armstrong-CCM Motorcycles in 1983, with production ending in 1987.

Can-Am resumed motorcycle production with a series of on-road three-wheel motorcycles, starting with the Spyder, using Rotax engines. As of 2020, there are three models: the Ryker uses the 2-cylinder 600 ACE and 3-cylinder 900 ACE, the Spyder F3 and the Spyder RT use the 3-cylinder 1330 ACE. 1000 V-twin 5sp.<ref>Template:Cite web</ref>

In the motorcycle world Rotax are particularly known for their single-cylinder engines of comparatively small to medium displacement. Several major motorbike manufacturers, who are otherwise renowned for their proprietary but bigger engines, use Rotax engines in their smaller models.

As an example of larger displacements, Rotax developed a 798 cc parallel twin engine with and for BMW, which was built from 2006 to 2020.

Brands using Rotax engines include:

• Aprilia Pegaso, Aprilia RSV Mille, Aprilia RSV 1000 R, Aprilia Tuono the Falco and Futura.
• Armstrong Motorcycles
• ATK 250, 350, 406, 560, 604, 605
• BMW F650, BMW F800S, BMW F800ST, BMW F800GT, BMW F800R, BMW F800GS
• Buell 1125, 604, 636 ccm
• Clews Competition Motorcycles
• Harley-Davidson MT500 MT350
• KTM
• Matchless
• MV Agusta
• MZ
• Classic Legends BSA Gold Star 650

Personal watercraft

As of 2020, all Sea-Doo brand personal watercraft from Bombardier Recreational Products are equipped with four-stroke, supercharged and normally aspirated, three-cylinder Rotax engines of the Advanced Combustion Efficiency (ACE) series.<ref>Template:Cite web</ref>

Off-road vehicles

Can-Am Off-Road vehicles from Bombardier Recreational Products are equipped with Rotax engines.<ref>Template:Cite web</ref>

Karting

The company introduced the Rotax Max for karting in 1998, and started organizing the Rotax Max Challenge in 2000.

Products

Aircraft engines

Rotax 912 installation

Rotax engines designed specifically for light aircraft include both four-stroke and two-stroke models.

Current models are:

• Rotax 912 series, four-stroke
• Rotax 914 series, four-stroke
• Rotax 915 series, four-stroke
• Rotax 916 series, four-stroke

Certified engines<ref>Template:Cite web</ref>

Model	912 A/F	914 F2/F3/F4<ref>Template:Cite web</ref>	912 S/iSc Sport	915 iSc A/B - 916 iSc3 B
Type Certification	25 September 1989	15 May 1996	27 November 1998	14 December 2017
Configuration	4-stroke, 4 cylinder boxer, spark ignition, liquid cooled heads, ram-air cooled cylinders, dry sump
Aspiration	natural	turbocharger	natural	turbocharger+intercooler
Fuel delivery	2× Template:Abbr carburetors		injection, dual channel FADEC
Fuel	automotive petrol or AVGAS
Stroke	61 mm / 2.40 in
Bore	79.5 mm / 3.13 in		84 mm / 3.31 in
Displacement	1211 cm3 / 73.9 cu.in		1352 cm3 / 82.5 cu.in
Compression	9:1		10.8:1	8.2:1
Gear ratio	2.27:1 / 2.43:1	2.43:1		2.55:1
Length	590 mm / 23.2 in	665 mm / 26.2 in	596 mm / 23.5 in	657 mm / 25.9 in
Height	375 mm / 14.8 in	531 mm / 20.9 in	398 mm / 15.7 in	398 mm / 15.7 in
Width	576 mm / 22.7 in		578 mm / 22.8 in
Dry Weight	57.1⁠–⁠59.8 kg / 125.88⁠–⁠131.8 lb	71.7⁠–⁠74.4 kg / 158⁠–⁠164 lb	58.3⁠–⁠64.4 kg / 128.52⁠–⁠142 lb	84.6⁠–⁠85.2 kg / 186.4⁠–⁠187.8 lb
Take-off Power	Template:Cvt	Template:Cvt	Template:Cvt	Template:Cvt
Take-off RPM	5800

Rotax 503

Historical models no longer in production include:

• Rotax 275, two-stroke
• Rotax 277, two-stroke
• Rotax 377, two-stroke
• Rotax 447 UL, two-stroke
• Rotax 503 UL, two-stroke
• Rotax 532 UL, two-stroke
• Rotax 535 certified two-stroke<ref>Template:Cite web</ref>
• Rotax 582 UL, two-stroke
• Rotax 618 UL, two-stroke

Karting engines

The Rotax MAX engine karting engine is a two-stroke engine series, launched in 1997.<ref>Template:Cite web</ref>

OEM

The company also produces unbranded engines, parts and complete powertrains for original equipment manufacturers (OEM).<ref>Template:Cite web</ref> Uses include motor bikes and scooters, with complete engines including the Rotax 122 and Rotax 804.<ref>Template:Cite web</ref>

External links

• Official Website
• Rotax Aircraft Engines
• List of Rotax engines applied to new-build aircraft