 | |
| Company type | Private company |
|---|---|
| Industry | Mechanical engineering |
| Founded | 1920 |
| Headquarters | , |
| Products | Internal combustion engines |
| Owner | BRP-Powertrain Management GmbH, BRP Holdings (Austria) GmbH |
| Parent | Bombardier Recreational Products |
| Website | www |
Rotax is the brand name for a range ofinternal combustion engines developed and manufactured by theAustrian companyBRP-RotaxGmbH & Co KG[1] (until 2016BRP-Powertrain GmbH & Co. KG), in turn owned by the CanadianBombardier Recreational Products (BRP). Under the Rotax brand, the company is one of the world's largest producers of light piston engines.[2]
Rotaxfour-stroke and advancedtwo-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.[3] 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.[4][5][6][7][8]
The company was founded in 1920 inDresden, Saxony, Germany, asROTAX-WERK AG, the name referring to the "rotanda axis" used in the 1906 bicyclefreewheel patent by Friedrich Theodor Gottschalk (1858-1932). In 1930, Rotax was taken over byFichtel & Sachs and transferred its operations, soon reduced to sales, toSchweinfurt, northern Bavaria, Germany. When this area came within reach ofallied bombing in 1943, the engine production of Fichtel & Sachs was moved further south-east within the Greater German Reich, toWels,Reichsgau Oberdonau, into the facilities of Reform-Werke Bauer & Co that had produced agricultural machines. To conceal this move, theRotax name was used.[citation needed]
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 nearbyGunskirchen in 1947, and ownership was transferred by the 1955Austrian State Treaty to Austria. In 1959, the majority of Rotax shares were taken over[9] by the Vienna-basedLohner-Werke, a manufacturer of car and railway wagon bodies.[citation needed]
In 1970,Lohner-Rotax was bought by the CanadianBombardier Inc. The former Bombardier branch, Bombardier Recreational Products, now an independent company, uses Rotax engines in its ground vehicles,personal water craft, andsnowmobiles.[3]
The original application for Rotax engines wasSki-Doo snowmobiles from Bombardier Recreational Products including two-stroke and four-stroke, turbocharged and naturally aspirated, two- and three-cylinder models.[10]
Rotax is one of the world's principal suppliers of aircraft engines forultralight aircraft,light aircraft andunmanned aerial vehicles.[2] Between 1985 and 1995, 60,000 Rotax engines were sold for aircraft propulsion.[2] In the light aircraft class, in 1998 Rotax outsold all other aero engine manufacturers combined.[4] Theirfour-stroke engines powered most U.S.-certifiedlight sport aircraft when they first appeared around 2004.[5] Over two decades later, Rotax engines remain the most popular line of engines for light sport and ultralight aircraft,[6][7] and the second-most-popular (afterLycoming Engines) for U.S.Experimental / Amateur-Built (E/A-B) aircraft.[8]
Rotax air-cooled,two-stroke engines began appearing on ultralight aircraft in the early 1980s, with a pair of single-cylinder, 7.1 kW (9.5 hp)Rotax 185s[11][12] powering the single-seatLazair ultralight by 1982.[12] Soon, the 19 kW (26 hp), single-cylinderRotax 277[11] 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 theFAA-mandated weight limits for ultralight aircraft which can be operated without a pilot's license).[13]
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 30 kW (40 hp)).[11]
Subsequent evolutions of the early designs included the two-cylinder, two-strokeRotax 377,Rotax 447, andRotax 503, all in production by 1985[11] (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).[14] Later two-stroke designs included theRotax 532 (circa 1984) andRotax 582, both of which augmented the air-cooling with liquid-cooled cylinder heads.[11]
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.[15]
Moving towards more demanding aircraft applications, Rotax, by 1989, developed a four-stroke, four-cylinder, engine: theRotax 912, with versions eventually ranging from 60 to 75 kW (80 to 100 hp), followed by a turbocharged 115 horsepowerRotax 914.[5]
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 normalaircraft propeller rotational speeds, (around 2300-2400 rpm) the engines use areduction gearbox.[5] They are also designed to acceptmotor spirit, with up to 10%ethanol content.[16][17]
These engines were initially given a 600-hour Time Before Overhaul (TBO), less than traditional light aircraft engines.[5][18][19] But operational experience and modifications to address specific reliability issues over time gradually extended the TBO to 2,000 hours.[5][18][19][17] 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.[8]
By 2014, Rotax had produced and sold 50,000 of 912/914 four-stroke engines.[5] Later models increased power, with several variants of the 912 family, and a new 100 kW (135 hp)Rotax 915 iS.[5][20]
The Rotax four-stroke aircraft engine line immediately dominated the emerging category of U.S.-certified "Light Sport Aircraft" (LSAs), powering most of them.[6][14] Onegeneral aviation industry media reporter found that 70-80% of the 66,000 aircraft he'd identified, worldwide, used Rotax four-stroke engines.[14] The 912/914/915 series also powers larger certified aircraft, including theDiamond Katana, and the twin-enginedTecnam P2006T and Leza/Lockwood Aircam.[6]
TheCan-Am division of Bombardier Inc. developed a line of motorcycles starting in 1971, powered by Rotax engines. The Can-Am motorcycle operation was outsourced toArmstrong-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 theSpyder, 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.[21]
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:
As of 2020, allSea-Doo brandpersonal 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.[22]
Can-Am Off-Road vehicles from Bombardier Recreational Products are equipped with Rotax engines.[23]
The company introduced theRotax Max forkarting in 1998, and started organizing theRotax Max Challenge in 2000.
Rotax engines designed specifically for light aircraft include both four-stroke and two-stroke models.
Current models are:
| Model | 912 A/F | 914 F2/F3/F4[25] | 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 cylinderboxer,spark ignition,liquid cooled heads, ram-air cooled cylinders,dry sump | |||
| Aspiration | natural | turbocharger | natural | turbocharger+intercooler |
| Fuel delivery | 2×CDcarburetors | injection, dual channelFADEC | ||
| Fuel | automotivepetrol orAVGAS | |||
| 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 | 59.6 kW (79.9 hp) | 84.5 kW (113.3 hp) | 73.5 kW (98.6 hp) | 100–117 kW (134–157 hp) |
| Take-off RPM | 5800 | |||
Historical models no longer in production include:
TheRotax MAX engine karting engine is a two-stroke engine series, launched in 1997.[27]
The company also produces unbranded engines, parts and complete powertrains fororiginal equipment manufacturers (OEM).[28] Uses include motor bikes and scooters, with complete engines including theRotax 122, theRotax 144 and theRotax 804.[29]
| External videos | |
|---|---|
 How Rotax Builds Aircraft Engines on AVweb |