Engine

Picture: First assembly steps ROTAX 912 UL, engine mount mounted on the fire shot is used for engine suspension.

There are a number of engines that are specially manufactured for microlight aircraft or are converted into aircraft engines. Self-built engines are reserved for specialists, as the requirements for an aircraft engine in terms of stability in continuous operation, reliability and low weight are not easy to achieve.

In addition, the engine type is tied to the certification of the microlight aircraft. The installation of another engine type which is not listed in the data sheet is theoretically possible but practically only possible with high technical, bureaucratic and financial effort.

A ROTAX 912 is presented below; it has established itself in the microlight sector. has prevailed. It is a 4-cylinder, four-stroke boxer engine. The engine is both liquid-cooled as well as air-cooled in parts. Water (coolant mixture) for cooling the cylinder heads, oil cooling for the engine block. The cylinders are ribbed so that they are slightly air-cooled.

A reduction gear is permanently installed to which a propeller is flange-mounted. The reduction ratio is 1:2.27 for the 80 hp engine and 1:2.43 for the 100 hp engine and above.

From the motorcycle sector (e.g. former BMW), carburetors from BING 64/32 are used. More recent versions of the ROTAX 912 are offered with fuel injection, the aforementioned BING carburetor is not used here.

Engines without ignition map are designed as stationary engines, i.e. ignition timing setting is designed for full load or almost full load (75%). Under partial load / idling, the fixed ignition timing is not optimal and the mixture is too rich.

As mentioned above, newer developments in the 912 series are equipped with fuel injection and turbochargers. This optimizes the engine system. This has an effect on the performance of the engines. However, this requires a considerable increase in electronics and costs.

However, this fell far short of the goal of offering a lightweight, high-performance engine at an affordable price (the original intention of ultralight aviation).

Maintenance and care is the key to technically trouble-free operation, especially in aviation. The aircraft manufacturer, the engine manufacturer and the manufacturers of the other components publish comprehensive documentation, instructions and, where applicable, warnings. These can usually be found on the manufacturers' service pages. Some associations also have an information system to provide information and further instructions such as urgent repairs, replacements or, if necessary, operating time restrictions or even operating bans on components or the entire aircraft. For the ROTAX 912 in particular, there are a number of technical bulletins relating to the inspection and replacement of parts.

According to normal legal understanding, companies are responsible for their products (warranty). The statutory product liability applies to all products. Some companies offer additional warranties, possibly also extended warranties. However, the warranty law and even the warranty behavior is, however, inadequate in practice, at least as far as the public is aware.

Even if the technical support (e.g. by telephone) may be very good, the handling of claims is said to be very cautious. Even small amounts (e.g. in relation to the purchase price of an engine) are said to be settled only reluctantly, even if the technical situation is clear to the customer.

With technical products, the intended use is decisive. The installation situation is also often individual. This offers a wide field for the motor manufacturer to accuse the user of misconduct or installation errors and thus evade responsibility.

The official manufacturer of the engine is Rotax in Gunskirchen / Upper Austria, which can be reached via its website.

https://www.rotax.com in general and for aircraft engines https://www.flyrotax.com

The distributor for Germany, Austria and other European countries is Franz in Schechen / Upper Bavaria.

https://www.flyrotax.com/de/franz

The Bing carburettor is manufactured by BING in Nuremberg / Middle Franconia.

https://www.bingpower.de

There is currently a one-off campaign underway to report faults with the ROTAX engine engine (SurveyMonkey). Supported by the DULV and AOPA.

https://www.bit.ly/3QX99Jj