MOONEY
M20TN - MODEL TYPE-S
SECTION VII
AIRPLANE AND SYSTEM DESCRIPTION
7 -- 23
AIRPLANE FLIGHT MANUAL
ORIGINAL ISSUE -- 04-02-2008
ICING PROTECTION
Continued operation of the induction system in the event of intake air being obstructed is pro-
vided by activation of the alternate air system. The alternate air is automatically or manually con-
trolled. When the door is opened, unfiltered, relatively warm air, from engine compartment, is
admitted into the induction system.
EXHAUST SYSTEM
Engine exhaust is collected by a system of headers. The left side cylinder exhaust is routed
through the left turbocharger. The right side cylinder exhaust is routed through the right turbo-
charger. Both the left and right side headers are connected to a single wastegate on the left side
that exhausts into the left tailpipe. The left and right turbochargers exhaust out of the cowling
through independent tailpipes. The left tailpipe also provides a vent for the crankcase oil breath-
er system.
Inspections for cracking, burn through, etc. is required during each maintenance activity and in-
spection of the tailpipes is recommended before each flight. Particular attention should be paid
to any crack, burn through, or loose tailpipe clamps that may allow exhaust to impinge on the
firewall. Do not attempt flight if the exhaust system is compromised.
FUEL INJECTION
The fuel injection system is of the multi--nozzle, continuous flow type which controls fuel flow to
match engine requirements. Any change in air throttle position, engine speed or a combination
of these causes changes in fuel pressure in direct relation to engine requirements. A manual
mixture control is provided for precise leaning at any altitude and power setting. A fuel flow sys-
tem is installed for digital read out of fuel flow in gallons per hour. However, fuel flow is NOT to be
used as reference for manual leaning. Use the TIT gauge for this purpose.
The continuous--flow system permits the use of a typical rotary vane pump with integral relief
valve. With this system there is no need for an intricate mechanism for timing fuel injection to the
engine. The fuel injector pump is equipped with a separator where vapor is separated by a swirl-
ing augmenter system from the liquid fuel and returned to the tank selected. The fuel injector
pump forces liquid fuel into the metering unit assembly.
The fuel metering unit/air throttle controls the amount of intake air admitted into the intake man-
ifold and meters the proportionate amount of fuel to the fuel manifold valve. The assembly has
three control units, one for air, in the air throttle assembly, and two for the fuel control unit.
The manifold valve receives fuel from the metering unit. When fuel pressure reaches approxi-
mately 3.5 PSI, a check valve opens and admits fuel to six ports in the manifold valve (one port for
each fuel nozzle line). The manifold valve also serves to provide a clean cut off of fuel to the cylin-
der when engine is shut down.
The injector nozzle lines connect the manifold valve to the six fuel injector nozzles.
The injector nozzles (one per cylinder) are “air bleed” type fuel nozzles which spray fuel directly
into the intake port of the cylinder. When engine is running, flow through the nozzle is continuous
and will enter the cylinder combustion chamber when the intake valve opens.
Since the size of the fuel nozzles are fixed, the amount of fuel flowing through them is determined
by the pressure applied. For this reason, fuel flow may be accurately determined by measuring
fuel pressure at the manifold valve.
ENGINE COOLING AIR
Ram air enters the forward part of upper cowl and flows through the cylinders, intercoolers, oil
cooler, and alternators using several baffles to control air direction. Hot air, off the engine, exits
the cowl thru lower cowl openings, located on either side of engine lower cowl, immediately for-
ward of the firewall.
