***************************************************************************
Flight Dynamics for the Savoia Marchetti S.81 with Piaggio P.X/RC15 engines
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[fltsim.0]
title=S81PX 13-1
sim=S81PX
model=
panel=
sound=
texture=13-1
kb_checklists=
kb_reference=SM81_PX_ref
atc_id=13-1
ui_manufacturer=Savoia Marchetti
ui_type=S.81 - Piaggio P.X/RC15 Engines
ui_variation=13rd Sq./26th Grp./9th Stormo B.T.
atc_heavy=0
atc_airline=
atc_flight_number=
description= This was the fourth and lightest variant of S.M.81. More powerful than previous versions only at low level. Performance at high level was poor. Squadron service from late 1936, primarily as maritime patrol and anti shipping assets, based in Eritrea and Somalia, from where they monitored and threatened the vital shipping lanes exiting the southern end of the Suez Canal. Strategic bombing capability retained to threaten Djibouti and Aden, but needed to bomb from lower levels than all other versions and was more vulnerable. This version was also selected by the Regia Aeronautica to train aircrew to fly IFR approaches in Italy. This plane, based on Gura's airport (Abyssinia) during 1935, belonged to 13rd Sq./26th Grp./9th Stormo B.T. Skin by Manuele Villa, April 2008.


[General]

atc_type=
atc_model=
performance=Press F10 and then lowest icon for step by step on screen handling notes.

[Views]

eyepoint = 6.35, -0.85, 2.9


[WEIGHT_AND_BALANCE]



empty_weight     = 15797	;including lubricating oil, flares, guns and ammunition
max_gross_weight = 23047	

Due to the very strong landing gear it was safe to land the S.M.81 at max gross after an emergency return. 

reference_datum_position     = 0, 0, 0
empty_weight_CG_position     = 0, 0, 0

station_load.0 = 1000, 0, 0, 0 	;5 crew with parachutes
station_load.1 = 2200, 0, 0, 0 	;normal bombload



Moments of Inertia

empty_weight_pitch_MOI   = 120000
empty_weight_roll_MOI    = 260000
empty_weight_yaw_MOI     = 300000 

empty_weight_coupled_MOI = 0.000     


[fuel]

Max fuel was 5765lbs = 961 USG modern unleaded AVGAS

The real aircraft had eight small tanks, six of which were between the engines. Outboard tanks were used only for maritime patrol. 

The S.81 had a maximum bomb load of 2,000Kg but the normal bomb load was half that which allowed 1820Kg of AVGAS to be loaded for a typical mission. When carrying the maximum possible bomb load of 2000Kg the maximum fuel load is 820Kg.

Those who wish to complicate the roll and yaw handling can move the left right tanks a few feet either side of CoG.

LeftMain  = 0, 0, 0, 287, 0	
RightMain = 0, 0, 0, 287, 0	
Center1   = 0, 0, 0,  93, 0

//Center2   = 0, 0, 0,  294, 0 ;after removing all bombload remove the // to simulate maritime patrol mission with max auxiliary fuel


fuel_type = 1                               
number_of_tank_selectors = 1                    
electric_pump=0


[GeneralEngineData]

engine_type = 0
Engine.0 =  4.2, -9.6, -2.3
Engine.1 = 12.2,    0,  0
Engine.2 =  4.2,  9.6, -2.3
min_throttle_limit = 0.2                      
master_ignition_switch = 1  

fuel_flow_scalar = 1		


[piston_engine]

The Piaggio P.X/RC15 

TOGA = 670hp nominal at sea level when a/p screw locked in fine pitch

War Emergency = whatever horsepower are produced subject to max 1.2 C2 and also subject to max 2475 rpm when screw locked in course pitch

Combat Rated Power = 700hp at 2350 rpm at 1500 metres in ISA when screw locked in course pitch

All published data, and the data explained below, assume all hatches closed, all turrets and the bomb aimers gondola retracted. Deploying to action stations in the S.M.81 reduced performance significantly. The drag associates with operation at action stations with turrets deployed may be replicated using the spoiler key in FS9.

cylinder_displacement=168.9
compression_ratio=6.0	
number_of_cylinders=9
max_rated_rpm=2350	//but war emergency rpm = 2475
max_rated_hp=700	//Combat Rating
critical_altitude=4920

fuel_metering_type=1
cooling_type=0
normalized_starter_torque=0.5
turbocharged=1
max_design_mp=35.9	//Rated, TOGA and war emergency
min_design_mp=0

emergency_boost_type=0
emergency_boost_mp_offset=0.000000
emergency_boost_gain_offset=0.000000
fuel_air_auto_mixture=0
auto_ignition=0
max_rpm_mechanical_efficiency_scalar=1.000000
idle_rpm_mechanical_efficiency_scalar=1.000000
max_rpm_friction_scalar=1.000000
idle_rpm_friction_scalar=1.000000

[propeller]

propeller_type=1
propeller_blades=3
gear_reduction_ratio=1.61			
propeller_diameter=12
propeller_moi=10
fixed_pitch_beta=20				
beta_max=20					
beta_min=20					
prop_sync_available=0                         
prop_deice_available=0                       
prop_feathering_available=0    
prop_reverse_available=0                                    
min_rpm_for_feather=0                       
beta_feather=0.0                               
power_absorbed_cf=0                           
minimum_on_ground_beta=20				
minimum_reverse_beta=0                     
defeathering_accumulators_available=0            
prop_auto_feathering_available=0             
min_gov_rpm=650.000000
prop_tc=0.010000

low_speed_theory_limit=80.000000


[airplane_geometry]

oswald_efficiency_factor= 0.67	  

wing_area               = 992.4 	;92.2 square metres
wing_span               = 78.7		;24 metres	
wing_root_chord         = 16.9
wing_pos_apex_lon       = 3.25

wing_pos_apex_vert      = -2.500
htail_area              = 175.000
htail_span              = 20.000
htail_pos_lon           = -36.000
htail_pos_vert          = 0.000
htail_incidence         = 0.000
htail_sweep             = 40.000
vtail_area              = 81.200
vtail_span              = 10.000
vtail_sweep             = 45.000
vtail_pos_lon           = -36.000
vtail_pos_vert          = 3.400
elevator_area           = 75.000
aileron_area            = 37.100
rudder_area             = 37.000
elevator_up_limit       = 18.000
elevator_down_limit     = 15.000
aileron_up_limit        = 18.000
aileron_down_limit      = 18.000
rudder_limit            = 25.000
elevator_trim_limit     = 15.000

spoiler_limit           = 60		;used for retractable turret and reatractable gondola drag
spoilerons_available    = 0
aileron_to_spoileron_gain = 0
min_ailerons_for_spoilerons = 0
min_flaps_for_spoilerons = 0
wing_dihedral           = 0
wing_incidence          = 0
wing_twist              = 0
wing_winglets_flag      = 0
wing_sweep              = 0

               
[Flaps.0]

Slow moving hand pumped flaps. Technical manual has only caution against use at 'high' IAS. The pump would break and the flaps would 'stick'. More or less self resolving in real life as they were too difficult to hand pump at high IAS. Vfe nominally set at 250 KmIAS, but correct IAS for deployment of each stage much lower and specified within the handling notes.

type= 1
span-outboard= 0.550
extending-time= 24			
system_type= 3

flaps-position.0= 0,0
flaps-position.1= 13, 138		
flaps-position.2= 19, 138		
flaps-position.3= 38, 138		




[Reference Speeds]

flaps_up_stall_speed    =  57		
full_flaps_stall_speed  =  49		
cruise_speed            =172.878255 
max_indicated_speed     = 170		

Some care must be excercised to moderate dynamic drag (IAS) < 310 KmIAS (but especially when descending) to avoid structural failure. Due to the high drag of the fixed gear this was not a material problem in real life. 



[Radios]


Com.1         = 1, 0
Com.2         = 0, 0
Nav.1         = 1, 0, 0		
Nav.2         = 0, 0, 0
Adf.1         = 1		;MFDF from delivery. 
Adf.2         = 0

Transponder.1 = 1		

Audio.1       = 1
Marker.1      = 1		;These aircraft would have had audio fan marker receivers 

[contact_points]

//GEAR
point.0 = 1, -40.67,  0,  -3.1, 1200, 0, 1.01, 40, 0.3 , 2.5, 0.9 , 0, 0, 0, 0, 0
point.1 = 1,   1, -8.82, -10.8, 1600, 1, 1.98,  0, 0.4 , 2.5, 0.85, 0, 0, 2, 0, 0
point.2 = 1,   1,  8.82, -10.8, 1600, 2, 1.98,  0, 0.4 , 2.5, 0.85, 0, 0, 3, 0, 0


//SCRAPES
point.3= 2, -1.600, -39.000, 0.000, 800.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000,5.000, 0.000, 0.000
point.4= 2, -1.600, 39.000, 0.000, 800.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 6.000, 0.000, 0.000
point.5= 2, -44.100, 0.000, 0.81, 800.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 9.000, 0.000, 0.000
point.6= 2, 16.45, 0.000, -6.07, 800.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 4.000, 0.000, 0.000
point.7= 2, 7.64, -9.56, -8.25, 800.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 4.000, 0.000, 0.000
point.8= 2, 7.64, 9.56, -8.25, 800.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 4.000, 0.000, 0.000

static_pitch = 11
static_cg_height = 10.9
tailwheel_lock = 0


[brakes]
parking_brake    = 1     
toe_brakes_scale = 0.25  ;drum brakes at this date were ineffective and subject to fading


[hydraulic_system]
normal_pressure = 732.0     //PSI
electric_pumps  = 0         //no electric pumps
engine_map      = 1,1,0,0   //pumps on Eng1,2

[LIGHTS]
//Types: 1=beacon, 2=strobe, 3=navigation, 4=cockpit, 5=landing
light.0 = 3, -5.59, -39.13, 0.06, fx_navred
light.1 = 3, -5.59, 39.16, 0.1, fx_navgre
light.2 = 3, -44.06, 0, 0.87, fx_navwhi
light.3 = 4, 7.2, 0, 2.46, fx_vclight
light.4 = 4,  -16.2,   0,  1, fx_vclight
light.5 = 5, -6.45, 19.19, -2.87, fx_SM74_landing
light.6 = 5, -6.55, -19.19, -2.87, fx_SM74_landing








[keyboard_response]
elevator =200, 1000
aileron  =200, 1000
rudder   =200, 1000

[direction_indicators]

direction_indicator.0=1,0
direction_indicator.1=2,0

[attitude_indicators]

attitude_indicator.0 = 1 
attitude_indicator.1 = 2 

[turn_indicators]

turn_indicator.0=2,0




[forcefeedback]
ground_bumps_magnitude1=2600            ; 0 - 10000
ground_bumps_angle1=8900                ; 0 - 35999 degrees
ground_bumps_intercept1=5.0
ground_bumps_slope1=0.6
ground_bumps_magnitude2=1200            ; 0 - 10000
ground_bumps_angle2=9100                ; 0 - 35999 degrees
ground_bumps_intercept2=0.085
ground_bumps_slope2=0.65
crash_magnitude1=10000                  ; 0 - 10000
crash_direction1=01000                  ; 0 - 35999 degrees
crash_magnitude2=10000                  ; 0 - 10000
crash_direction2=9000                   ; 0 - 35999 degrees
crash_period2=75000                     ; in microseconds
crash_duration2=3500000                 ; in microseconds

[stall_warning]
type=1						;unlikely in real life

[exits]
number_of_exits = 2
exit_rate.0 = 0.27                              ;Percent per second
exit_rate.1 = 0.5                               ;Percent per second


[EFFECTS]
wake=fx_wake
water=fx_spray
dirt=fx_tchdrt
concrete=fx_sparks
startup=fx_engstrt_jenny
touchdown=fx_tchdwn_s, 1


[electrical]
max_battery_voltage = 12
generator_alternator_voltage = 12
max_generator_alternator_amps = 90

[flight_tuning]

p_factor_on_yaw          = 0.01
torque_on_roll           = 0.01
gyro_precession_on_yaw   = 0.01
gyro_precession_on_pitch = 0.01


[autopilot]
autopilot_available= 1
direction_indicator=1
attitude_indicator =0
default_pitch_mode=0	// no pich control
max_bank=25		
max_bank_acceleration=1
max_bank_velocity=3
default_bank_mode=2     
default_vertical_speed=0
autothrottle_available=0
pitch_takeoff_ga=8.000000
max_pitch=0
max_pitch_acceleration=0
max_pitch_velocity_lo_alt=0
max_pitch_velocity_hi_alt=0
max_pitch_velocity_lo_alt_breakpoint=0
max_pitch_velocity_hi_alt_breakpoint=0
max_throttle_rate=0.100000
nav_proportional_control=9.000000
nav_integrator_control=0.250000
nav_derivative_control=0.000000
nav_integrator_boundary=2.500000
nav_derivative_boundary=0.000000
gs_proportional_control=9.520000
gs_integrator_control=0.260000
gs_derivative_control=0.000000
gs_integrator_boundary=0.700000
gs_derivative_boundary=0.000000
yaw_damper_gain=0.000000

