EAA Sport Aviation - August 2011

to get to those hidden spots without having to disassemble the engine. This is easy maintenance!

Normally, crankshafts and connecting rods in aircraft engines
run in sleeve bearings that have high friction and need high oil pres-
sure. Metalwork is using ball and needle bearings (less heat
development) that need less lubricant on much lower pressure. In
case of mechanical oil pump failure—it is driven directly by the
crankshaft—the engine can run for 30 minutes using the oil mist
present in the crankcase for lubrication. The crankshaft ball bear-
ings are designed to sustain a minimum of 3,000 engine hours at full
throttle. The piston rods are monolithically built (single piece)—a
contribution to greater robustness. The crankshaft is pressed
together, and connecting sur-
faces have longitudinal
grooves to prevent possible
contortion (shift/movement)
of connecting surfaces. Two
valves per cylinder are driven
by overhead camshafts (one
per cylinder bank) that are
connected by a chain to the
central, over-the-crankcase-
positioned shaft.

ENGINE VARIANTS

● B22D, 95 hp, 3300 rpm, direct drive, price € 12,500/€ 13,800*

● B22L, 115 hp, 3950 rpm, reduction gear, price € 14,500/€ 15,700

● B22R, 130 hp, 4550 rpm, reduction gear, price € 17,900/€ 19,000

*The higher price includes the factory-supplied FlyStar. Separately ordered the EMS costs € 1,600.

REDUCTION GEAR
Except for the basic B22D engine that is direct drive, the L and R
versions have a propeller speed reduction unit functioning without
mechanical or hydraulic shock absorbers in the classic meaning of
the word. Metalwork developed an electro-hydraulic system that
uses two-step motors mounted on the camshaft and controlled by
the central engine management system/computer. Engine vibrations
are dampened by compression reduction of the engine at and below
1900 rpm, resulting in a smoother-running engine. The system func-
tions automatically; no special pilot action is needed. If this system
should fail, the engine runs with a lower
compression ratio, developing 30 percent
less power.

INJECTION AND IGNITION SYSTEM

As in any modern engine, the fuel-air mixture is controlled by a dedicated engine control unit (ECU) with emergency mode. The ECU calculates the amount of injected fuel based on engine speed, intake air pressure, engine oil temperature, air temperature, and absolute atmospheric pressure. The ECU (located on top of the engine) also controls an electric fuel pump, which could be backed up with a mechanical pump. One injector per cylinder pair is located directly behind the throttle body on each cylinder head. A second set of injectors can be installed—the holes for their installation are already present. The fuel lines are made of steel.

The basic B22 engine is fitted with one ECU and one spark plug per cylinder. Since March 2011, new cylinder heads are in production with the capability of accommodating two spark plugs per combustion chamber. Using the second (optional) electronic control unit the system can be duplicated for redundancy.