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TRANSMISSION SYSTEM

It a composite crankshaft is safe?

All the parts of the crankshaft are made from carbon steel and are cold press fitted, with a significant interference.  Different from competitors, in the B22 AEROPOWER engine, all the parts are fitted with a quenched key to avoid the relative rotation between the parts in any situation..

Are the crankshaft ball bearings and the connecting rod needle bearings safe?

Both types of bearings have been calculated for 3000 hours at maximum power of the engine (in the future version B22S AEROPOWER 150CV@5900) and maximum RPM.  In addition the crankshaft is riding on four main bearings instead of the standard three. In this way it is possible to achieve a better distribution of the loads and each crank is between two bearings; the centrifugal loads on each bearing are balanced with the counterweight of the crankshaft.  The ball bearings can work without the possibility of failure even with low lubrication and with low oil pressure.

Why doesn’t the B22 AEROPOWER engine have a mechanical torque reduction?

On the B22 AEROPOWER engine there is an innovative electro-hydraulic system (ADC) to deal with torque vibration.  This system replaces any mechanical torque reduction that is a critical mechanical component subject to wear. The ADC system is based on the variation of the compression ratio controlled by an electro-hydraulic system.  The ADC system has been designed so that any failure of hydraulics or electronics does not compromise the flight safety

What advantages does an electro-hydraulic torque reduction system offer with respect to a mechanical system?

No wear, start up and stop of the engine without kickback, weight reduction, no maintenance or control or regulation are required.

What happens in case of a failure of the ADC system?

The engine doesn’t stop and can run for all the time necessary without any problems or damage.  The engine may run with a reduction of power of around 25%, or it may happen that the engine will have a higher or an irregular engine idle.

Is it possible to use a constant speed propeller?

Yes, any kind of constant speed propeller can be used, either hydraulic or electric types, with the exception of the hydraulic system designed for the mechanical governor.  The B22 AEROPOWER gearbox has been designed to integrate a very compact and lightweight hydraulic constant speed propeller system.  This system can be easily installed on the gearbox without disassembling any part of the engine.

TIMING SYSTEM

Why does the B22 AEROPOWER engine have an OHC (Over Head Camshaft) with a timing chain?  Why doesn’t it have an OHV (Over Head Valve) with a pushrod and rocket arm like most aeronautic engines?

The OHC timing system with a timing chain has a lower number of components with respect to the OHV timing system which reduces the risk of failure.  In order to work perfectly the OHV timing system needs tappets with a hydraulic adjuster to compensate for the thermal expansion of the engine.  A failure of the tappets with hydraulic adjuster lubrication will cause an immediate stop of the engine.

Is the timing chain safe?

The two chains (one for each bank) are driven by the secondary shaft, which means that the chains are short and the rotation speed is lower, this is particularly good for the life of the chain.  Furthermore there is a chain guide with a chain tensioner that guides the chain over its length avoiding stress on the chain caused by fluctuations.

Is the chain tensioner safe?

Yes.  The chain tensioner uses a system with two twin springs and is safe even if one the two springs is broken.  The chain tensioner has been designed to reduce the mechanical stress on the chain with the goal of extend the chain life.

Why doesn’t the B22 AEROPOWER engine use tappets with a hydraulic adjuster system?

The B22 AEROPOWER engine uses a timing chain with a mechanical tensioner so that the timing system is not influenced by the thermal expansion of the engine.  During the design phase of the B22 AEROPOWER engine a solution with a hydraulic adjuster system was rejected because of the number of negative aspects of that type of system.

How do you adjust the clearance between the cam and the cam follower on the B22 AEROPOWER engine?

It is possible to adjust the clearance between the CAM and the tappet using a calibrated shim put on the top of the tappets.  The replacement of the shim is quite a simple operation that doesn’t require disassembling the mechanical components of the engine.  Thanks to the special material used for the valves, valve seats and shim, the replacement of the shim is a maintenance operation necessary only after many hours of running.

INLET and EXHAUST SYSTEM

Why are the air intake manifolds so big and long?

The B22 AEROPOWER manifolds are designed to be so long in order to have a RAM effect, or a dynamic overboost (an increase of the static air pressure in the manifolds) at maximum RPM.  This allows for a greater mass flow through the engine and hence increases engine power.  The effect is associated with the reflection of the pressure waves inside the manifold. When there is a perfect ratio between the length of the manifold and the pressure wave speed the RAM effect is created.

Why isn’t there an airbox on the B22 AEROPOWER engine?

The B22 AEROPOWER engine is provided with manifolds designed to create an intake RAM effect that increases the mass flow to the engine and hence increases the engine power.  For that reason the use of an airbox would be inappropriate.

Which solution has been used to prevent and avoid the icing in the intake system?

There are two kinds of icing: one in the intake manifold and one on the throttle.  The first one happens if in the intake manifold there is a “venturi” (necessary with a carburetor).  With the “venturi”, the air flow is subject to sudden expansion that produces a drop of the temperature of the air that, in particular situations, cause the water vapour to freeze.  This cannot happen on the B22 AEROPOWER because there isn’t a “venturi” in the intake manifold.  The second type of icing on the throttle is due to the impact of the air on a cold surface.  On the B22 AEROPOWER the throttles are very close to the valve in the head of the engine so that the throttles are heated.  On a carburetor the throttle is usually positioned far away from the heat of the engine, and is usually joined to the cylinder head with rubber which works as a heat shield.

Without the airbox, does the engine suck hot air from the engine compartment? In this case does it reduce the engine performance?

No, of course the engine fairing must be designed to guarantee a correct cycle of air in the engine compartment with adequate intake for the engine.  Sometimes engineering an intake to pressurize the airbox is not very simple and, moreover, it doesn’t allow for the creation of pressure waves phased with the valve.

Why don’t the exhaust headpipes have the same length in the standard B22 AERPOWER exhaust system?

During the design phase priority was given to the dimension and other aspects connected to the installation of the exhaust system.  Normally the intake manifolds are more important for the performance of an engine and on the B22 AEROPOWER they are all the same length.  This isn’t the same on the engines of the competitors.

The exhaust headpipes aren’t the same length, does this reduce the performance of the engine?

The ruseult of some test done on the B22 AEROPOWER with an exhaust system with headpipeswith the same length there areonly  2, or  3 HP more, but there is more constant torque in function of the rpm.

FUEL SYSTEM

Why isn’t there a mechanical fuel pump?  

The electric fuel pump is safer than a mechanical fuel pump there is no risk of oil contamination in the fuel due to a leakage of the seal.  Moreover mechanical pump cannot guarantee the necessary pressure at start up.

Is the fuel circuit in pressure safe in case of a crash?

Yes, the circuit is sealed.  With a carburetor the circuit is not sealed and the fuel can leak from the float chamber.  In case of a crash or a stop of the engine the fuel pump is immediately switched off.  This cuts out the risk of a continuous fuel leak which is typical of a carburetor.  The use of a small section pipe, made of steel, for the fuel rail avoids the “Spout” effect.

Is the vapour lock possible?

Thanks to the pressurized fuel circuit and the use of a high flow rate pump and a return fuel circuit the possibility that the vapour lock phenomenon can occur is rare. In case of a vapour lock it is enough to switch on the auxiliary pump for a few seconds to remove the vapour from the fuel circuit.

Is it complicated to make the fuel circuit?

A fuel rail and a fuel regulator are already installed on the engine.  It is only necessary to connect the pressure line and the return line to the fuel hub on the engine.

Can the injectors break?

The injectors can break in case of presence of impurities in the fuel, but the use of an adequate fuel filter (supplied with the engine) prevents from this kind of problem.

INJECTION AND IGNITION

What are the advantages of an ECU (Engine Control Unit)?

An ECU optimizes the engine combustion at any engine speed: the injection is phased with the air flow in the manifold to achieve a homogeneous air/fuel mix which allows for a reduction in the fuel consumption.  With fuel injection it is possible to perfectly manage the start up and warm up of the engine and to provide adequate carburetion at any altitude.  The ECU doesn’t need maintenance, it weighs less and the fuel system is completely sealed.

Is the ECU safe?

A modern ECU is a SMD (Surface Mounted Device) which is different from the 25-30 years old electronics still in use on some aircraft engines today.  This technology is not affected by vibrations. The ECU and all its components are designed to work up to 85°C (185°F).  

Why is the ECU installed on the engine?

The ECU is installed on the engine to avoid failure of the electronic system loom due to reciprocal vibration between the engine and the aircraft.  The ECU is installed on the highest point of the engine so that any water infiltration in the wiring loom does not flow towards the ECU.  In this way the installation of the engine is easier and safer.

Why is there only one spark plug on the standard version of the B22 AEROPOWER?

While most engines for ultralights use ignition with a capacity coil, the B22 AEROPOWER use a more modern system with an inductive coil and advanced mapping in the ECU.  The ECU has the mapping of the dwell time (recharge time of the coil) in function with the battery voltage that allows for constant spark energy.  The use of the ECU allows for a constant air/fuel mix in any condition.  Because the B22 AEROPWER is not air cooled it doesn’t need any additional fuel to control the engine temperature.  All the above factors help to increase the spark plug life. On request, the B22 AEROPOWER with two spark plugs and a backup ECU will be available.

What happens in case of a failure of the generator?

With the battery in good condition the engine can run for at least 15-30 minutes.  The ECU is designed to work from a battery voltage of 8.5 Volt.

What happens in case of a failure of the battery?

Over 1500 RPM the engine can run continuously without any power reduction.

COOLING SYSTEM

The B22 AEROPOWER is water cooled.  Is it more critical in case of failure of the water with respect to other engines that use water and air cooling systems?

The hottest and most critical part of the engine is the engine head.  In an engine with an air cooling system for the cylinders and a water cooling system for the head, a failure of the water cooling system won’t cause a piston galling but it will cause camshaft or valve galling. The use of a water cooling system guarantees a homogeneous temperature of the engine thus avoiding thermal shock and distortions.  In the cold season, the common practice of reducing the air flow on the water and oil radiator never includes the reduction of air flow on the cylinder which basically increases the difference of temperature between the cylinder and the engine head.

Is it necessary to reduce the air flow to the engine during the winter season?

No.  The engine doesn’t require any direct air flow because the cooling system is equipped with a thermostat and there isn’t an oil radiator so the oil temperature is almost independent from the external temperature.

Is the thermostat safe?

Yes, it is a component that doesn’t break easily.  With the thermostat it is possible to have a steady temperature of the engine in any condition of flight, and this improves the life of the engine, and it works much better than any system to regulate the air flow to the water radiator.

LUBRICATION SYSTEM

Why is it not necessary to have an oil radiator on the B22 AEROPOWER?

The B22 AEROPOWER has adopted a crankshaft on ball bearings and a needle bearing for the connecting rod.  This considerably reduces the stress for the oil lubrication and consequently the heating.  The water cooling system is very efficient and can dissipate the heat from the engine by itself.

Why doesn’t the B22 AEROPOWER have a dry sump?

A separate oil tank is not only an additional accessory that needs to be installed and monitored but it can be the cause of serious engine damage.  When the return to the oil tank is connected to pressure due to the blow-by, any problems connected to any radial shaft seal or any gasket of the engine will immediately cause reduction of the pressure inside the crank case with a reduction of oil return flow to the tank and consequently a reduction of the quantity of oil to the oil pump and to all the lubrication circuits.

As the B22 AEROPOWER doesn’t have a dry sump, what happens in case of turns or other flight manoeuvres?

The B22 AEROPOWER has adopted “gravity” valves that are between the crank case and the oil sump.  These valves let the oil flow from the crank case to the oil sump but stop the flow in the opposite direction.  During flight manoeuvres these valves stop the oil from coming out of the sump guaranteeing a correct quantity of oil for the oil pump.

What happens to the B22 AEROPOWER in case of a failure of the oil pump?

Thanks to the crankshaft on ball bearings the B22 AEROPOWER will still work with power reduction.  It is mandatory to land as soon as possible.

Why doesn’t the B22 AEROPOWER use the engine lubrication oil to lubricate the gearbox?

Because it is more common that in the use of gears that can produce metallic particulates it is better to keep away from the engine pistons or crankshaft bearings.  Moreover, to increase the gear life and reduce noise, it is recommended that lubrication for the gears must have a higher viscosity than engine lubrication oil and it must work at a lower temperature.

 OTHERS

Which accessories does the B22 AEROPOWER need to work?

The B22 AEROPOWER engine is supplied with all the accessories that are needed to be mounted to make it work (fuel pump, fuel filter, wiring loom and FLYSTAR for the version with the FLYSTAR) with the only exception of the standard B22 water radiator, standard B22 exhaust system and auxiliary fuel pump, that are available as options.  An oil radiator is not necessary.

What does it mean that the B22 AEROPOWER has a hole for the boroscope inspection?

During the design phase, great attention has been paid to maintenance procedures.  On the B22 AEROPOWER a hole in the crank case has been created, through which it is possible to introduce inside the B22 the flexible tube of a boroscope, at the end of that flexible tube there is an objective lens and on the other side an eyepiece or a camera.  With that instrument it’s possible to do an inspection of the engine without disassembling the engine, therefore reducing the maintenance cost.

What is the FLYSTAR kit?

The FLYSTAR is an “all in one” instrumentation system.  The kit includes a backlit LCD display, engine parameter sensors (preinstalled on the engine) and flying parameter sensors all connected to the display.  With the display it is possible to keep the engine parameters under control and at the same time to view all the information necessary for the flight.  LED’s and a buzzer help to be immediately alerted in case of a problem.  The FLYSTAR kit is very easy to install considering that most of the sensors are already installed on the engine as well as the wiring loom.

Is the FLYSTAR kit necessary to make the B22 AEROPOWER engine work?

The FLYSTAR kit is not necessary to make the B22 AEROPOWER engine work but it helps to keep all of the engine parameters under control including the running time.  It is also necessary for the “Extended Flying Range” function.  That function is controlled by the FLYSTAR in combination with the ECU via CAN line reducing the fuel consumption and extending the Flying range.

What is a CAN line?

The CAN line is a common protocol developed on modern electronic units for vehicle applications that allows the different installed units to talk each other and to transmit information.  On the B22 AEROPOWER there is a CAN line installed between the FLYSTAR and the ECU using only two wires.

Why are the cylinder liners in the B22 AEROPOWER not in aluminium?

The B22 AEROPOWER is a water cooled engine.  That means that the heat transfer between the piston and the cylinder is less critical than on an air cooled engine.  The cast iron cylinder liner offers a better glide and is less subject to galling, and is very easy to replace.

What it is necessary to do to install the B22 AEROPOWER?

The installation of the B22 AEROPOWER is very simple.  The B22 AEROPOWER must be installed on the airplane using the attaching points integrated in the engine, then the pressure and return fuel lines must be joined, the “service” wiring loom must be connected, an adequate GND must be connected to the engine body and a 12 volt wire to the start relay.  All the rest of the accessories are preinstalled on the engine.  Please carefully follow all the instructions indicated in the installation manual.

How do you attach the B22 AEROPOWER to the aircraft?

The engine has four integrated attaching points in the rear for wall mounting which are prepared to fit the shock absorbers.  Alternatively, the engine can be installed using four adapters for the bed mounting. The adapters must be screwed to the oil sump and are also prepared to fit the shock absorbers.

Why doesn’t the B22 AEROPOWER have the rear attaching points in the same positions as the competitors?

The reason is that the B22 AEROPOWER has a different configuration and mass distribution than its competitors, which means that the frame for the engine must be designed for the B22 AEROPOWER.

Why is the start motor on the B22 AEROPOWER small?

The B22 AEROPOWER uses a system to reduce the compression of the engine at start up. With this system it’s possible to use a smaller starter engine and a smaller battery than a 2.2cc engine would require.

Why does the B22 AEROPOWER propeller turn clockwise (looking at the p.t.o. side of engine)?

This has been imposed by a technical compromise that has been made during the design phase. There is a large selection of propellers available.  Turning clockwise doesn’t affect the control of the airplane.

What happens to the B22 AEROPOWER in case of overspeed?

Overspeed cannot occur.  The ECU has been programmed to progressively reduce the power of the B22 AEROPOWER as it gets close to the maximum RPM allowed for each version of the engine.  This is to avoid the typical limiter cut used with the ECU.  With power reduction it is possible to achieve a sort of soft limiter because the engine is unable to pass over the speed limit.  In any case, the mechanical design limit is much more that the one controlled by the ECU.