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MWfly Aeropower Engines

MW Fly Aeropower Engine

In 1994 METALWORK Engineering was founded by eng. Guido Fantini and eng. Stefano Marella. They are both are graduates of the Milano Politecnico in Aerospace Engineering. The goal of the company was to produce an engine for the L.S.A. (Light Sport Aviation) market.

The U10 engine project was started in 1995, which was a two cylinder 1000 cc engine 70CV. The project was presented in 1995 to the Light Sport Aviation show in Bassano (Italy) and then to Aero in Friedrichshafen (Germany) in 1996 gaining much interest. In 2003 it was set aside as the market had shifted towards more powerful engines.

In 2003 the B20 project commenced, a horizontally opposed engine with a displacement of 2000 cm3 / 2 liter. The project continued with great strides thanks to the experience gained during the U10 project and soon became the B22 with 2.2 liter displacement. The first flight tests were made in 2006. In 2011, after more than 2000 hours of bench testing and numerous hours of flight testing the engine had reached good reliability, making it ready for commercialization.

B22 / B25 Designs

MW B25 aircraft engineMW B25 aircraft engine

These engines are available in sixteen (16!) standard versions with power from 100 HP up to 155 HP, four cylinder horizontally opposed (boxer) direct drive or geared (+5 kg), left and right rotation, tractor or pusher, weighing less than 85 kg (187 lbs).

MW Fly Engines have been developed specifically for use in light aircraft and are manufactured to the highest standards. Standard equipment on their liquid cooled engines include an integrated oil tank, a dual ignition and fuel injection system, thermostat, water tank with pressurized cap, electric starter with relay, an alternator of 350W, shock absorbers and all sensors needed for a EMS system connected via the CAN bus (aerospace protocol).

MWfly engines are equipped with a fully redundant injection and ignition system. Installed on each engine are two ECUs, two sparks for each cylinder working with different ignition coils, two different injection and ignition circuits (one pickup for each ECU). The ECUs are working contemporary, with master and slave strategy; in case of ECU failure, the second one takes over and the engine continues to run.
Furthermore, each ECU can work in Limp Home mode, in case of sensor, battery or generator failure. The ECU system is compliant with IECEDD68-2-6 (sinusoidal vibration environment test).


There are basically two engines regarding displacement: the B22 with 2.2 L and the B25 with 2.5 L. Both have a direct and a geared drive option, the geared version is available with two different gear reduction ratios. The A version is 1:1.731 and the B version has a reduction ratio of 1:1.958. The B gear version runs the crankshaft of the engine to a bit higher RPM (4700) for more power. A hydraulic speed governor was developed in 2015 and is available.


Below the common specifications of the basic engine models the MW Fly produces in their factory:

Engine ModelB22B25
Displacement2201 cm3 (134 in3)2545 cm3 (155 in3)
Weight79,5 kg (176 lbs) dry
Stroke x Bore81 x 93 mm (3.18 x 3.66 inch)81 x 100 mm (3.18 x 3.93 inch)
Compression Ratio10.5:1
Cooling SystemLiquid with mechanical pump
FuelMoGAS min. AKI 90, R.O.N. 95, M.O.N. 85, 100LL
Fuel Consumption175 gr/hp.hr
Alternator12 V, 26 A, 300 W
FADECDual ECU & Ignition, CAN Data

Note: each of these models can be supplied with a gearbox and with left or right hand propeller rotation for pusher applications. A turbo charged model is in development.

Detailed specifications in these pdf files: B22 Direct 100 130 hp, B22 Geared 120 130 hp, B25 Direct 115 155 hp, B25 Direct 135 155 hp.

Feature list

Due to the sheer number of possible engine configurations (16) MW Fly compiled a pdf file which lists all models and technical features their engines have: click the next link for an engine overview.


With so much engine configurations possible, MW Fly offers a very good alternative to the more commonly used aircraft engines like ROtax, ULpower... You can really say that the company has an engine for every LSA application and more.

New / Rebuilt?

Every new MW Fly engine may use two (2) TBO cycles. An engine rebuilt by MW Fly has only one (1) TBO cycle left. The TBO for the B22 is between 1800 and 2200 hours, the B25 has an TBO between 1500 and 2000; this depends on the configuration of the engine.

Company information

MW Fly can be contacted at the addresses below:

MW Fly s.r.l. Head OfficeMW Fly North America
Via Trento 331500 Thomas Argue Road
20017 - Passirana di Rho (MI), ItalyCarp - Ontario, Canada
+39 02 9318 3892 +1 613-864-1547
[email protected] [email protected]
www.mwfly.it www.mwflyna.com
www.facebook.com/MWFLY-196108087066743 www.facebook.com/mwflyna

Text and images used with permission of MW Fly.

Written by EAI.

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