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Flight Dynamics for the Savoia Marchetti S.M.81 with Alfa Romeo 125/RC35 engines
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[fltsim.0]
title=SM81 AR125/RC35 218-4
sim=SM81_AR125
model=
panel=
sound=
texture=218-4
kb_checklists=
kb_reference=SM81_AR125ref
atc_id=218-4
ui_manufacturer=Savoia Marchetti
ui_type=S.81 - Alfa Romeo AR125/RC35 engines
ui_variation=218th Sq./54th Grp./37th Stormo B.T.
atc_heavy=0
atc_airline=
atc_flight_number=
description=This was the second version of the S.81. It was optimised for bombing strategic targets in Europe from medium level and was the version most frequently employed during the Spanish Civil War. Squadron deployment from late 1935. Later augmented by aircraft with more powerful AR126 engines, (q.v.), but not retired. These were however the first variants relegated to transport duries and most serving in that role by the end of 1939. This plane, based on Benghazi's airport (Lybia) during 1941, belonged to 218th Sq./54th Grp./37th Stormo B.T. Skin by Manuele Villa, April 2008.
[fltsim.1]
title=SM81 AR125/RC35 214-5
sim=SM81_AR125
model=
panel=
sound=
texture=214-5
kb_checklists=
kb_reference=SM81_AR125ref
atc_id=214-5
ui_manufacturer=Savoia Marchetti
ui_type=S.81 - Alfa Romeo AR125/RC35 engines
ui_variation=214th Sq./52nd Grp./34th Stormo B.T.
atc_heavy=0
atc_airline=
atc_flight_number=
description=This was the second version of the S.81. It was optimised for bombing strategic targets in Europe from medium level and was the version most frequently employed during the Spanish Civil War. Squadron deployment from late 1935. Later augmented by aircraft with more powerful AR126 engines, (q.v.), but not retired. These were however the first variants relegated to transport duries and most serving in that role by the end of 1939. This plane, based on Catania Fontanarossa's airport (Sicily,Italy) during August 1937, belonged to 214th Sq./52nd Grp./34th 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, 3
[WEIGHT_AND_BALANCE]
empty_weight = 15907 ;including lubricating oil, flares, guns and ammunition
max_gross_weight = 23111
Due to the very strong landing gear it was safe to land the S.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 overload 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 overload 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 = 0.1
master_ignition_switch = 1
fuel_flow_scalar = 1
[piston_engine]
The Alfa Romeo 125/R.C.35 (licence built Bristol Pegasus III).
TOGA = 680hp at 1.12 C2 at sea level (rpm varies with altitude density)
War Emergency = 680hp at max 1.12 C2 and max 2300 rpm below 3500 metres
Combat Rated Power = 650hp at max 1.1 C2 and max 2200 below 3500 metres
Design and tactical cruise 485hp at 0.9 C2 and rpm not exceeding 2200 (optimum 5Km)
Econ cruise 400hp at 0.8 C2 and rpm not exceeding 2090 (optimum above 5Km)
critical_altitude=11480 //Rated and WEP at different RPM
cylinder_displacement=194.78
compression_ratio=6.0
number_of_cylinders=9
max_rated_rpm=2200 //Rated
max_rated_hp=680 //TOGA and WEP
fuel_metering_type=1
cooling_type=0
normalized_starter_torque=0.5
turbocharged=1
max_design_mp=33.4 //TOGA and WEP
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=1.53
propeller_diameter=12.5
propeller_moi=10
fixed_pitch_beta=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=10.0
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
beta_max=0
beta_min=0
[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 turret 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 = 170
max_indicated_speed = 170
Some care must be exercised to moderate profile drag (IAS) < 310 KmIAS (but especially when descending) to avoid structural failure of the tail. 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
Adf.2 = 0
Transponder.1 = 1
Audio.1 = 1
Marker.1 = 1
[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 = 10
static_cg_height = 10.3
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 //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
[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
[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 = 0.0
torque_on_roll = 0.0
gyro_precession_on_yaw = 0.0
gyro_precession_on_pitch = 0.0
