SR71 for FS2004(FS9) Operation Guide

Optimized for Flight Simulator and this model based on the real world SR71 Pilot Manual.

Paul R. Varn
Revised May 3, 2008

Contents:

SR71 for FS2004(FS9) Operation Guide
Credits
Attributes
Weather Environment
Reality Gauges
Specifications

Trivia

Dynamic model replacement for AIR and CFG files for public freeware release of Alpha Sim SR71a.

The book "Lockheed SR-71" by Jay Miller provided a wealth of information I didn't have access to before. Thanks to Gary Hall for loaning it to me. Also thanks to Gary Hall for finding the unclassified pilot manual online. This provided massive amounts of information.
Other references include: "Janes all the World Aircraft."
Boeing Museum of Flight (A12 display and SR71 cockpit.)
"SR-71 Revealed" by Richard Graham. Personal interviews with former pilots, RSO's and Crew Chiefs.
Testers:
Gary Hall (Habu lover)
Marv Thompson who devoted a huge number of hours providing quality feedback and tremendous assistance with assembling/testing gauges for the panel. A truly tireless tester.

IMPORTANT!!! USE AT YOUR OWN RISK! THIS AUTHOR WILL NOT ASSUME ANY RESPONSIBILITY FOR ANY FAILURE WHATSOEVER, IN HARDWARE or SOFTWARE.
NO CLAIM IS MADE AS TO REAL-WORLD ACCURACY OR AUTHENTICITY.
Features and images in this document may change without notice.
This model requires an experienced Flight Simulator enthusiast who might enjoy high altitude, high performance aircraft. The flight model is as realistic as my skill and FS2004 will allow. All FS realism settings should be set to maximum for realistic flight. The skill level required to fly the aircraft as it was meant to fly is considerable. I suggest new pilots work up to this aircraft by starting with FS2004 training scenarios and up through faster two-engine jets like the Lear. When confortable with the FS interface, flight procedures, and high speed, multi-engine aircraft, you'll be ready to step up to the fastest plane in the world.

Attributes:

Added REAL after-burner (shift-4.)
Afterburner effect using smoke effect triggered by AB key.
Added Drag Chute (/ spoiler key - Panel indicator needed)
Note: Model will not fly with drag chute activated!
The COL has been carefully calibrated to closely follow the trim table in the official SR71 pilots manual.
Engine Spike position activated with flaps keys providing performance boost above Mach 1.7. Improper spike positioning can also cause Un-Starts.
COG now conforms to real world specs.
As of May 2008 a dramatic improvement to the speed limit. Raised from 457 KIAS to over 500.
With reality gauges installed (explained below) unstarts are now possible. They are not random events and may occur from rapid weather changes or pilot in-attentiveness.

You will read many references to weight and weather in provided documentation. These two variables affect the performance of the model dramatically. Especially at high altitude 40K to 50K feet higher than typical airliners fly. You cannot fly at maximum altitude, at max weight in very high or low air pressure where the temperature is excessively cold. Stable flight is a careful balance of flight path planning, altitude, speed, and fuel load. Considering the aircraft has no flaps or spoilers, it has a 200+ knots air speed range of stability at Mach cruise.
The eight segments that make up the six fuel tanks have been carefully placed to provide the required balance shift during a normal fight through natural attrition which should not require pilot intervention except if the pilot loads the tanks incorrectly. A COG warning annunciator gauge will assist the pilot in correcting the balance which should be minimal. Fuel loading and maintenance is covered in depth later.
In short, the fuel is heavy in the rear at start to facilitate take off rotation. If it's too high, rapid rotation causing tail strike may result. During mach climb, the fuel shifts forward to maintain correct COG for mach fight.
Near the end of the flight when the fuel load is low, the weight shifts to the rear again (largely through giving up the balance to the heavy engines in the rear) for rear balance on landing which assists the AP in maintaining a high AOA and low nose drop rate for touch down. There are forward and rear COG limits. Mach 3 speeds after the CG has shifted rear past 20% may cause pitch instability. This should normally occur after fuel weight has dropped below 16K lbs. If you are still high and fast under 8K lbs fuel, you might have trouble getting down to land in time without refueling. Typical descent fuel weight is between 16K - 18K lbs and CG below 20%. When nearing finall approach, manual pump back to +21.8 may be necessary.

The Panel is a collection of gauges from other planes which fit the general theme of grey-black high performance aircraft. Some gauges are not accurate. In some cases where accuracy was abosolutely necessary, I constructed primitive text-based XML gauges so the pilot could fly the plane to real-world procedures and specifications. It's not pretty, but functional. As my elementary gauge making skill improves, I'll replace more of the gauges and add more realisitic ones. I invite gauge artists who enjoy high performance aircraft to pariticipate in creating a freeware panel that does justice to this amazing aircraft.

SR71-FS2004 Weather environment:
LAYERS (51K)
This graphic from NASA illustrates the earth's atmospheric layers. The SR71 cruises at altitudes between 21 to 27 Km riding the Tropopause. The air temperature reaches its coldest near this point and warms both descending and climbing. In Flight Simulator 2004 (FS) the built-in Jeppeson weather simulator includes data only up to around 45K ft (about 40-50K lower than the SR cruises.) Above this limit, the simulation creates steadily warmer temperatures (which mimics the chart above.) Unfortunately, the coldest the sim sets at 45K ft is 10-15C WARMER than is normal for 60 to 80K ft.
When using Jeppeson (or similar emulation like Vatsim) by the time you reach SR cruise altitudes, the air is as warm as if you were flying at 30K ft. This makes high speed flight impossible without over-heating. What makes high speed flight possible is the thin-cold air at the extreme altitudes of air breathing engines. This is why a more accurate weather simulator is needed like Active Sky(AS.) I worked with the designers of this program to encourage them to emulate the Tropopause conditions for high performance aircraft like the SR71 and Concorde. This flight model is specifically designed to operate with Active Sky. Without it, the model will fail. When ANY program sets the temperature of the highest layer, FS will gradually produce warmer temperatures above the highest defined layer.

As AS creates weather around the world, it will set the top layer to different altitudes and temperatures. Because of this, you will never have the same flight conditions twice. Sometimes you will get weather near or colder than the operating limits. Sometimes much warmer. As in the real world, pilots flying the Concorde and SR71 had to ride a range of altitudes and speeds to continually optimise the conditions for maximum range and speed. I call it "Threading the Amospheric Needle." In the sim, the most important indicators are the Exhaust Gas Temperature (EGT) Air Speed Indicator (ASI) and Fuel Flow (FF.) To prevent structural damage or stalls, the aircraft has to be flown between a 200 knot speed band (300 - 500 KIAS.) To prevent engine failure, the combination of Compressor Inlet Temperature (CIT) and EGT must be kept within their limits which are strongly influenced by the Static Air Temperature (SAT) Engine RPM and air speed.

The tools you will use to juggle the temperature and structural limts are Altitude and Mach speed.
By keeping the mach setting so the ASI is kept as close to 400 KIAS as possible you will fly right in the middle of the structural limit range between failure and stall. By adjusting the altitude of your flight between 72K and 92K feet to keep the EGT as close to 800C as possible, you manage the temperture of the air to prevent engine damage. The last of the three legs of the flight management is Fuel Flow (FF.) By keeping the fuel rate under 20K lbs/hr per engine, you will get the maximum range the flight model is designed for.
As you read further into this guide, you will see many references to speed and altitude limits. I hope this explanation will give you the background to understand why these limits are there and to assure you they are indeed real world. Pilots had to plan and fly their plan to cooperate with these limits. Unlike airliner flight where you set a altitude and speed and keep them for the whole cruise flight, the SR71 "Habu" pilot can rarely enjoy that kind of leasure. Most flights will be realtively calm and uneventful. Some will have you changing speeds and altitude frequently to stay ahead of the changing weather situation. Configuation for AS and the most trouble-free flight is covered in the flight prep portion of this document.

The following graphic from NASA illustrates the effect of altitude and pressure:
Alt_Press (28K)
As you fly, FS is constantly comparing the distance to the plane's position to many weather stations the weather program has loaded into memory from online weather servers.
FS uses the calculated closest station pressure for the current pressure. In remote areas of the world, these stations may be hundreds or thousands of miles apart with vastly different weather. This strategy can cause large pressure jumps from station-to-station as you get closer to a new station and leave another behind. You may also leave a relatively sparce station area to a dense area where a new station becomes "closer" every few seconds. This character is complicated by the SR's great speed traveling around 1/2 mile per second. Active Sky has the unique ability to create false "virtual" stations in remote areas between real station data. This helps solve another problem the FS weather simulation causes:
When there isn't enough station data to provide a local weather environment within apprx 60 miles, FS drops all loaded data and sets a local default condition of pressure 29.92 and -58 degrees C at 45K ft. When this happens, if the weather you were flying in up to that point was vastly different, you may get a very large altitude transition and engine power spike (because the engines are sensitive to temperature.) The virtual stations AS creates will help to fill in the gaps between stations, but errors in station data will still cause the FS default conditions to load once in a while. When the aircraft is flying in pressure changes representing hundreds of feet in an instant, the speed and lift of the aircraft can change drastically. Needless to say, this digital weather emulation leaves a lot to be desired compared to the real world. For this reason, the Habu pilot has to be attentive. You can be assured, it is possible to have hundreds of hours of trouble-free flight. I hope I've made you aware though it isn't always that way. Even in the real world, there were some damaged and crashed SR71 planes.

TAKEOFF (211K)
2D (282K)
VIRTUAL (178K)

The real plane:
ASM_3D1 (58K)

Reality Gauges:
Since I first started working on this model I recently added several reality gauges which reflect some true real world limitations of the aircraft. As exceptional as it is, it's not a space shuttle. Real world pilots had limitations placed on what they could do. In addition, there were physical limitations to the airframe and engines.
These are discussed again later in this document within relevant sections:

CITEGT: ENGSTATE (46K)The Compressor Inlet Temperature was not permitted to exceeded 427 degrees Centigrade. The CIT temp gauge will display both engines in white text while in normal operation, yellow within 10 degrees of limits, and red within 2 degrees of limit. If the limit is exceeded for 30 seconds or more (428+C) one engine will be commanded to fail. The failed engine will display "FAILED!" in red text. It cannot be restarted. This should be a very rare occurrence. This same gauge provides the correct Exhaust Gas Temperature with built-in De-rich electronic "trimming" system to lean the fuel to air mixture and reduce over-heating. There is a yellow "LIMIT" indicator when the EGT reaches 830 C (continuous operating limit) and orange and red "hot" indicators for 845C and 900C. EGT below 400 will indicate "COLD."
The image at the right shows the engine stack at three states of performance: shut down, 28K ft 400 KIAS, and operating near limits above mach 3.5.

Annunciator:
ANNUN (24K)System state and failure warning system. Many of the warnings mimic actual plane warning lights although for space and practical purposes many are left off. The systems and warnings are as follows:
WarningDescription
Oil PsiPsi drops below 25
OIL
TEMP
Below 15C or above 177C
FUEL
PRESS
Below 15 Psi
OIL
LEVEL
Below 15%
HYD
PRESS
Below 2000psi or above 3500psi
HYD
LEVEL
Below 25%
BUS
VOLTS
Below 22 Volts
GEN
OFF
Generator Switch Off
FailEngine Failed
GEAR
GEAR TR
or
GEAR LIMIT! or
GEAR DAMAGED!
Pitot HGEAR will display when throttle is low and aircraft below 3000ft. GEAR TR when the gear is in transit.
Pitot H indicates PH switch is off
SPEED HI and STALL WarningsFuel LowSPEED HI and STALL WARN in yellow and red to indicate various levels.
Fuel Low indicates tank1 is below 5400 lbs AND tank 4 is blelow 4050 lbs
COG WarningsEmer BatCOG warning system calculates speed and weight under various conditions and warns when COG is out of config with yellow (minor) and red alerts.
Emer Bat indicates battery is being drained.

Drag Chute:
DSSTATES (13K)The drag chute gauge has three states: not deployed, auto-armed, and deployed. Full chute deploy takes apprx 5 seconds. The drag chute can no longer be deployed while in the air. If you arm the chute on the ground, the ground contact sensor will deploy the chute. You can arm the chute while in the air and when there is ground contact of the main wheels AND the throttle is lowered to idle, the chute will deploy. Standard procedure requires the chute not be deployed in corss wind until front gear makes contact.
Note: When retracting or "jettesoning" the chute, it takes 5 seconds for the lever to return to is normal position. The image at the right displays these three states. Notice the "normal" un-deployed state has a black center. The armed for auto deployment state shows an orange-ish center but otherwise looks like the un-deployed state. The deployed state has a bright green center and is extended toward the pilot on an red-ish shaft. The gauge cannot be activated by mouse at this time.

TEB: Below the engine throttles are two TEB chemical counters, one for each engine. The counters are maintained separately for each engine. Each time an engine is successfully started or the AB is enabled, the TEB count for the cycled engine will lower by one. You start out with 16 "shots" of TEB. When the count reaches zero, the affected engine cannot again be restarted or its AB enabled. The TEB count is only lowered if the engine start is successful or the throttle position is 70% or more for engaging afterburners. An engine which is fully functioning will remain working if the counter reaches zero until another failure occurs.

Spike:SPIKE (33K) The Spike position gauge is a critical key to the ability of the J-58 to obtain Mach 2 and 3. Together with front and rear bypass doors, they prevent super sonic air from entering the compressor and stalling the engine. At this time, the door operation is not yet implemented. In the real SR, the spike is maintained by a computer. In this sim, it's pilot operated in place of bypass door operation. I've put about 30 hours into trying to make the spike automatic, but any xml code I've tried will not move the flaps. If I ever get that working, then I'll consider coding "fake" bypass door position knobs which the pilot will operate.
If the spike is out of position the text read-out will change from white to yellow and display a counter. If the counter reaches 15 seconds or more, one engine (they each have a 50% chance of failure) will have its AB disabled. It will cost you a TEB hit to restart it. Beginning at Mach 1.6 and faster, if the counter reaches 30 seconds or more, the engine will have its fuel shut down (emulating an engine "unstart.") This condition is displayed by the square black light on each side of the panel changing to bright red. Failures to position the spike properly below Mach 1.6 will only cost a TEB hit and then only if the AB happens to be engaged. USSTATES (2K)Unstarts were a well known problem on the SR71.
The term comes from the idea that close to Mach 1.6 and above, supersonic flow inside part of the inlet has "started" and a shock wave builds behind the spike lowering the intake pressure. Loss of the shock wave control causes the same symptoms as a compressor stall.
When the engine unstarts, if you correct the spike (changes back to white and counter stops) before the engine RPM drops to 22%, the engine will restart itself. If you wait too long, you'll have to restart the engine yourself with the starter switch on the panel or contrl-e. Each successful engine restart will cost you a hit of TEB. Restarts are normally performed at Full Military throttle to prevent another compressor stall. The spike also has to be in the correct position throughout the start procedure since your air speed may have dropped considerably during the failure.
Technically, the sequence of 1st disabling the AB is not true reality. In reality the AB typically flamed out when the engine shut down. What I wanted to do is provide an initial non-catastrophic warning you were about to lose an engine, but make it still relatively easy to recover: correct the spike and re-enable the associated AB. I'm considering other ways of modeling a minor fault prior to shut-down other than disabling the AB first. Regardless, an unstart will still require the loss of two TEB hits to ignite the engine and restart the AB. The Unstart light will only be lit until the fuel valve gets re-enabled. Several engine annunciator lights are a further indication you have a failed engine (as well as all the engine gauges indicating low.)
Note: It is very important to have the special gauge "SelectCorrect.xml" installed. This gauge corrects the FS2004 timing error on some panels when performing multi-select operations. Without this gauge (which is invisible) attemps to select only one engine using the key sequence e1, or e2 or e12 will fail and only the #1 engine will be selected. When this happens, attempts to move the throttle or operate the AB will affect only one engine and normal two engine operation cannot be re-established.
The normal procedure for re-igniting one AB when it fails is to select the failed engine with the key sequence e1 or e2. Re-engage the AB with shift-F4, then re-select BOTH engines for normal operation by pressing the key sequence: e12 BACKSPACE. It's imporant to tap BACKSPACE at the end of ANY operation in Flight Simulator where a number key has been pressed. Failure to observe this rule may result in FS "remembering" you had started a mutli-key operation and you might have it complete at an unexpected or critical moment. ALWAYS tap BACKSPACE after every multi-key sequence or you have retured to 1:1 sim rate after using other sim rates.
Note2: When operating near the spike movement Mach speeds, the sudden loss of power may nearly instantly cause the spike setting to self-configure correctly. In this case the fuel flow will re-enable and the engine self-start without pilot interaction. AB re-ignite by the pilot is still necessary.
Note3: The SelectCorrect gauge has a critical timing which the pilot needs to cooperate with. I have found it's best to wait about 1 second after pressing the engine select sequence before activating the AB or engine restart switches and key presses. Otherwise, you may not get the engine selection you expected.
Note4: An engine failure or unstart may cause the spike to move at a very small portion of its normal rate.

ABThrottle: This gauge is an enhancement to the main panel throttle. The SR71 has a combined throttle AB control (like most reheat jets.) To activate the AB the throttle is moved to a hardware stop, then the handle is pulled out-away from the base on a spring and the throttle lifted over the stop into the minimum AB setting. ABSTATES (15K)Current Implementation: On the ground the throttle will not permit movement past 70% (full military power.) To increase beyond 70% you have to engage the AB (which simulates lifting the throttle over the stop. Once the AB is engaged, the throttle can be moved at will. If you reduce the throttle below 70%, the AB will disengage automatically. In flight, the AB will also disengage below 70% but you can use the throttle at ANY setting without the AB, even 100%. The gauge also provides a digital readout of the throttle setting percent. I added this feature for testing other code I was working on and grew to depend on the added position visibility it provided. I decided to make it permanent. A newly added feature is AB off/on indication. Since removing the Concorde Nozzel area gauge, I replaced the AB lights by changing the throttle position number colors. Green for "normal" military power and white for AB on. The image on the right shows these two states with full military power on the left and 85% with AB engaged on the right. Also shown are the two TEB counters at the bottom.
New for this revision, on the left side just under the throttle percentage readout for engine 1 is an engine selection readout. The purpose is to help confirm you have the correct engine selected for operation. Shown in the graphic is both engine 1 and 2 is selected so the digits "12" are shown. When only one engine is selected, the display will show a 1 or a 2.

As you all well know, faults of any kind are not a normal part of FS simulations. The built-in random failure system is so unlikely and unrealistic no one wants to use it. These faults take some getting used to, but are an attempt to help wannabe "Habus" appreciate the skill and technical complexity associated with this unique aircraft. Although Airliner pilots are known to sleep at the stick from boredom, Habus could not!. Go to sleep in this aircraft and you'll find yourself in a reset in short order. These faults are not random. The pilot has to fail to react to out of limit flight perameters for them to happen. In a normal flight, you will not have any faults.

Specifications:
Fuselage:
Length: 103' 10"
Height: 18' 6"
Wing Span: 57' 7"
Wing Area: 1,605 sq' (some sources claim 1,800 ft sq)
V Stab Area: 70.2 sq'
Gross Weight (MTOW): 172,000lbs
Zero Fuel Weight: 80,000 lbs
Engines:
Weight(2): 13,000 lbs (6,500 lbs ea)
20' long, 4',5" wide
(2) P+W JT11D-20B (J-58) Turbo Ramjet.
32,500lbs static thrust @ sea level
(45,000 lbs with after-burner)
Single Rotor, 9 stage 8:8:1 ratio compressor.
ENGINT (79K)
Starting RPM: 3,200
Idle RPM: 4,000
Max RPM: 7460?
Min RPM above M 2.5: 6100
Typical Cruise RPM: 7100
Overspeed RPM: 7450 < 300C CIT, 7300 > 300C CIT
Cruise Inlet/Engine power ratio: 80%/20%
Core airflow: 450 lb/s
Max inlet spike movement = 26 inches.
Fuel Load (JP-7) at 100,000 lbs Gross Weight: 11,570 lbs
Fuel Capacity: (real world) 83,302 lbs JP-7 (12,200 US gal @6.9 lbs/gal)
Fuel Capacity: (this model) 80,653 lbs FS "JetA" (12,038 US gal @6.7 lbs/gal)
Unusable: 32.4 Gal (217 lbs)
Standard temperatures and pressures:
Rated Cruise: Mach 3.20 @80,000ft
Fuel Rate at Ground Idle: 4800 - 6300 lbs/hr

Fuel Rate MAX Take Off Full AB: 65K lbs (40,000+ simulated)
Fuel Rate at refuel speed and alt: 12K lbs/hr
Fuel Rate (rated cruise): 36-41,000lbs/hr
Fuel Rate (Average Climb): 22,500 lbs/hr
Fuel Rate (Average Descent): 16,500 lbs/hr
Full Fuel:
Min Take off Runway length: 9,000ft. (with after-burner)
10K lbs fuel or less:
Min land Runway length: 7000ft
Typical Runway Take off Roll (45K lbs fuel): 4800ft
Max Crosswind landing: 25 knots dry, 20 knots wet.
Max Ground Tire Speed: 238 KAES, 239 KIAS, 275 MPH
Tire Cooling: 9 minutes for every 14,000ft or 2.75 miles of taxi distance at 70 deg F.
Tire Pressure: 400 Psi
Max initial breaking speed 10K lbs fuel: 209 KIAS @70 deg F
Min Ejection Altitude: 15,000ft
Touch Down Vertical Speed: Typical- 50 to 100 fps, Max- 600 fps
V Speeds (45K lbs fuel):
V1 = 156KIAS
Vr = 180 KIAS
V2 = 210 KIAS
Vr(full weight) = 205KIAS
Max Speed: Mach 3.45/510 KIAS RANGE_CEILING (176K)
Recommended Operational Ceiling: 85,000ft (model tested stable to 95K ft)
Normal Cruise Altitude: 81K ft westbound, 80K ft Eastbound.
Range: 3,250 miles un-refueled (rated cruise using Active Sky temperatures)

Minimum Single Engine Approach = 200 KIAS 25,000 lbs fuel.
Minimum Go Around Alt = 300 ft.

Temperatures:
From 600 to 900+ degrees Fahrenheit on the airframe.
Temperatures on the J-58 engine exhaust reach 3200 degrees.

Min Operating temperature = -75 deg C

Sub-Mach Max Climb Speed (no turbulence) = 400 KIAS
Sub-Mach Max Climb Speed (max turb penetration) = 350 KIAS

Minimum Turn Airspeed: 220 KIAS

Landing Speeds:
Fuel lbsApproach SpdTouchdown Spd
<= 10K175 KIAS155 KIAS
20K185165
25K190170
30K195175
40K MLW205185

Typical AOA at the above speeds and weights are 10 to 12 degrees, not to excede 14 degrees (tail strike.)

AOA Flight:
Max AOA below 25K ft = 18 deg
Max AOA Subsonic 25K+ ft = +10 deg
Max AOA Supersonic 25K ft - 70K ft = +8 deg
Max AOA Supersonic 70,000ft = +6 deg
Max Inlet Temperature: 427C (801F)

Drag Chute deploy:
5 seconds full deploy after activated on touch down. 1/2 G decel. Nosewheel contact required before activation with cross wind.
Max Drag Chute Deploy Speed: 210 KIAS
Drag Chute Attachment fail Speed: 30K+ lbs fuel

Max Sub-Mach Climb to Cruise:
Full Stop Break Release to 24K ft in two minutes.

Active Sky Weather Simulation:
Design Mach Speed = 3.2 (above 35Kft)
Note: Mach speed over 3.2 and under 75K ft may cause unexpected-instant overspeed with weather changes. Overspeed should now be very rare when Normal operating speeds are used with Auto-Throttle.
Maximum Operational Mach = 3.35
Overspeed Mach = 3.45
Maximum Indicated Air Speed = 505 KIAS
Note: AS has to be operated in "Force Constant Route Pressure" mode for high speed mach in remote areas like Northern Canada and North Atlantic.

Max Safe Altitude (Active Sky) = 85Kft (without special auth.)

Max Rated Altitude = 92K ft (can go higher when weather permits.)

Max Pitch at cruise = 7 deg (Speed loss/Stall Instability @ 6.0 deg)
PITCH WARNING!!!: Do not let pitch rise above +7 deg or below level on the Artificial Horizon while above Mach 3.

Min IAS at cruise (above M3) = 310 KIAS (real world) 280 KIAS (simulated)
Note: Descend rapidly if the weather system causes a sudden drop in IAS to a value near this speed.
Mach 3 stall: Below 240 KIAS

No Power Glide (80K ft Mach 3.2):
375KIAS @ -11,600 ft/min
6 minutes to 10Kft (102nm)

Refueling:
Normal Alt- 25K - 35K ft (35K feet with latest tankers.)
AOA 3 deg low fuel
AOA 6 degrees full tanks
Typical distance between tanking: 2000 miles
Refuel Rate: 6,000 lbs/min
Typical Refuel Time: 15 minutes

Max Deceleration above M 1.8 = 1 mach per 3 minutes
Below Mach 1.8 = No limit

MLW: Not Limited (suggested 40K lbs fuel max)
Note: APP AP is very unstable at this weight
Normal Landing weight: 10K lbs fuel or less
Touch and Go Limit: 25K lbs fuel

CIT Compressor Inlet Temperature:
Max Inlet Temperatures (mach 2.8 @85Klbs gross weight)
SAT(C)CIT(C)
-69250
-61270
-57280
-52290
-44310
(mach 3.0 @85Klbs gross weight)-
SAT(C)CIT(C)
-67300
-60320
-57328
-52340
-45360
Nominal Inlet Temperatures (Mach 3.2 20K lbs fuel)
SAT(C)CIT(C)
-66.8350 (typical Cruise)
-59.8370
-56.5380/Max: 427C @ M 3.38
-52.9390
-49.5400
-46.2410
RPM:
cit_rpm_chart (161K)

EGT:
Idle: ~430C @ sea level (typical)
Max start temp (idle) = 565 C
Normal Cruise Range: 780 - 820C
Continuous Limit: 830C
Emergency Zone = 805 - 845 C up to 15 minutes
Red Zone: 900 C up to 2 minutes
950 C up to 15 seconds

egt_cit_chart (167K)

COG:
Modeled MAC in FS2004 = 51 ft (wing + forward fuselage chine).
Typical range: +17% to + 24%
Max at cruise: +25%
Max Take off and land: +22
Max below Mach 0.9: +24
Min COG above Mach 1.8 and 11,570 lbs fuel: +17
Min below Mach 1.8 and 11,570 lbs fuel: +14.5
Ideal Landing: +21.0 to +22.0
Mach 3.30 = 24.3% MAC

Mach 3 Environment Temps:
Interior: 300 deg F
Nose: 800 deg F
Windshield: 600 deg F
Exhaust: 1,200 deg F (649C)

Oil Pressure:
Min safe operating = 35 PSI
Normal = 40-60 PSI

Hydraulic Pressure:
Normal = 2200 - 3000 psi at or above 3000 Engine RPM
Reduced Control = down to 1500 RPM Control Failure = below 1500 RPM

Electical:
2ea 60KVA direct drive generators. 155/200 volt, 400 cycle.
2ea 28 volt, 25 amp/hour batteries.
Emergency AC buss (supplied by battery 1): 1KVA.
Battery Duration (essential equip only) 40 minutes.
External MD-3 or MD-4 power connector.

--------------------- FLIGHT PROCEDURES: ----------------------

This general overview of technique for flying this aircraft in FS2004 is not real-world but based on manipulating the sim to obtain consistent results. Active Sky weather is assumed. FS and SB3 weather should not be used as the data doesn't support altitudes over 45K ft.

o PRE START PREPARATION- FLIGHT PLAN loaded into GPS or another navigator that performs turn prediction. FS2004 GPS turns about 2.8 miles prior to the waypoint at high speed. This is JUST enough to maintain control during turns. At cruise, waypoints should be 500 miles apart or more if they have moderate turns, No-turn waypoints can be as close as 100 miles. When flying over water to your destination (ATC hate mach speed in their space) a careful flight Plan will include a way point close to the coast (assuming your destination is somewhat inland) for use as a descent calculation target. This is explained in the descent profile later.

Fuel Loading:
If using SFP or NAV3, range and fuel planning should be VERY close using the following table:
CLIMBCRUISEDESCENT
SPEED9001790700
FUEL RATE225004000016500
VERTICAL RATE1750(ave) 1800(ave)
ALT 81000
Fuel Tank Diagram

Note: The rear tanks (Center2 and L/R Tips) typically contain 30% less fuel to conform with max take-off COG of 22%. Typical practice is to fill all front tanks to 70% and the rear tanks (Center2 and L/R tips) which when set to 40% will provide 22.1% COG and apprx 45.5K lbs fuel on take-off.

Easy Rule of thumb:
To set typical take off weight of 45K lbs, set the 5 top tanks (font and mains) in the FS fuel menu to 70% and the bottom 3 tanks (rear and trim) to 40%. This will provide just enough fuel over the 22% COG that it will be burned off and ready to go by the time you reach the runway. Use this formulae for all your fuel loads (rear 30% less than front) and you'll have a nearly perfect fuel load for every flight.

In order as they appear in FS fuel dialog:
Front Tanks:
Laux = Tank 2 L
Lmain = Tank 3 L
Cntr = Tanks 1 + 1a Front Trim
Rmain = Tank 3 R
Raux = Tank 2 R
Rear Tanks:
Cntr2 = Tanks 4 + 6a
Ltip = Tanks 5 + 6b Rear Trim
Rtip = Tanks 5 + 6b Rear Trim

Fuel distribution is as follows (rough):
< NOSE to TAIL(111ft) >
1,1a2LR3LR4,6a 5,6b
<  pilotCntrLRauxLRmainCntr2 LRtip >
| <wing<engCTR> wing>
o o
These tank assignments and positions are based on FS2004's built-in default tank attrition schedule which chooses the order in which tanks deplete until empty. Habu pilots considered 60K lbs fuel weight a "heavy" jet. At the typical take off wieght of 45K Lbs fuel, you'll find the plane nimble and fast-climbing. If you need a fuel load over 70K lbs, it's best to take off with 45K lbs and plan on an air refuel.
END FUEL PREP.

WEATHER PREP::

The SR71 is sensitive to pressure more than wind speed and temperature because of the high altitude. Near the flight limits large pressure changes can throw the flight model well beyond its operational limits. If forecast pressure areas over the course of your flight have the potential to be below 29.45 you should use the Active Sky Enhanced Version feature "Force Constant Pressure" while preloading Flight Plan or descend to a safe altitude near the problem area. Pressures over 30.10 are problematic because they force you to fly very high (which can be fun, but increasingly risky.) You can expect to fly 92K ft or higher to barely maintain M 3.20 safely with a pressure of 30.35.

Check for strength and direction of prevailing winds. Typically, in the northern hemisphere, you will have mostly head winds traveling West and tail winds heading East. I add 1000 lbs when going West and subtract 1000 from the estimate going East. The exception would be flights more N/S than E/W where I don't modify the estimate.

81,000ft should be used for flights East and 80,000 for west. Although the model supports flights up to 92K ft, unstable weather over coastal transition boundaries (300 - 500 miles from land crossing over large bodies of water) may cause highly unstable flight. AS does not support temperature layers above 82,000ft. As you climb above this, temps actually INCREASE rather than decrease. This can cause failures of the type where sudden weather changes can cause an extreme engine efficiency change with consequential overspeed or stall.

FSUIPC and Active Sky optimization:
Active Sky-
AS_CFG (220K)

Note: 170 miles suppression, 5 min update interval settings.
The default setting of 100/10 does not work at all because the SR will fly 320 miles or more in 10 minutes at cruise.
Using a 5 min interval (although it has the potential of keeping the SRs flight distance updated) has the problem that FSUIPC cannot load all the dense area stations in 5 minutes. Even 6 minutes is not enough time sometimes. At 7 minutes, the station loading sequence completes, but errors in the station data and FSUIPC station count limits still cause "blanking." Blanking is where there is no valid local data. This can be caused by no local stations close enough to the aircraft location, or the station ID being set to the weather simulator cannot be found (bad location description) in which cases FS creates a default weather conditon which is "Clear and Calm" in the weather dialog presets. The "blank" or "Clear and Calm" condition is unsuitable for flying the SR at high altitudes. In AS build 479 and later I have had acceptable results using 170/5 but blanking persists in parts of the world where station data contains errors (Many parts of Canada cause blanking.) On my 2.2 GHz AMD, turning off update throttling greatly assists the speed up update writing so the stations will all write before even 5 minute updates. The cost is a few more stutters during updates.

Your flight setup procedure should include use of the "New Route" button at the main screen. When clicked, set the cruise speed to 1750 and "Import" an FS flight plan of your flight route. This will cause AS to pre-scan all the weather along your route and create some optimizations including "Virtual" stations between large gaps in real world stations. With "Constant Pressure" selected both real world and virtual station data will be modified slightly to reduce the severity of pressure changes.
I have experimented with "Constant Temperature" a bit and although it has the potential of smoothing out large temperature changes, it can also cause them. If the temperature profile the program selects to simulate is unfriendly, you are stuck with this profile for the whole flight. With this feature unselected, you at least have a chance a bad profile could improve.

Sometimes even with a flight plan pre-loaded and pressure smoothing, the condtions can still be totally unfavorable to flying the SR. The options are to change your flight to another part of the world, or not pre-loading a flight plan and letting the AS program create a more dynamic "load as you go" environment (which is AS's default condition.) Virtual stations will still be created (based on the suppression and update intervals you entered.) This dynamic environment may cause more disruptions in your flight, but you have an equal potential of getting an acceptable high altitude condition at any given time as a bad one. Instead of a bad condition the whole flight, you may get periods of acceptable condtions.

Weatherset: A useful tool for checking the quality of the weather generation is a free program which comes packaged with FSUIPC called Weatherset. FS2004 and X users should use Weatherset2. This program displays all the weather data being sent to FSUIPC by the weather program in a numerical display (rather than the FS weather dialog tabed graphical display. This lets you see all the current weather settings at a glance without scrolling or tabbing. Take a look at the temperatures above 50K ft and the current pressure. If you pre-loaded a flight plan with force constant pressure, the current pressure shown will only deviate slightly through the flight.

Another useful tool comes with the online multiplayer connection program FSINN. Along with a large package of tools in the main FS menu is the "Pressure" indicator. This places a current pressure display in the sim so you can see what the current pressure is at all times. This is helpful because above 18K ft, setting the altimeter in FS forces a constant 29.92 which is standard practice for airliners. However, the SR71 is a military jet not an airliner and compesating the altimeter was not standard practice. For this reason, I elected to provide a non-compensated altitude reading in the main panel "Triple" gauge. You can use this to compare the compensated display in the main altimeter to the non-compensated in the triple display to tell if you are flying in higher or lower than normal pressure. As you get more experienced, you will come to expect certain IAS readings at certain altitudes. Higher or lower than normal air speeds at Mach 3.2 are an indication you are flying in unusually low or high pressure.

FSUIPC-

The following settings in the WINDS section of FSUIPC are necessary to smooth the wind for Mach speed flight. If you are using the free version, you cannot set this resulting in less than satisfying weather conditions in all aircraft: CHECK "Smooth Changes" Knots or degrees/second = 0 OR for this many seconds for each 1 degree = 2 After weather clear delay smoothing by seconds = 0 CHECK "smooth only when airborne."

NOTE on PRESSURE: In practice using AS weather, pressures during M3+ flight OVER 1024.4 (30.25mb) or UNDER 997.3 (29.45mb) are problematic. You can expect to have to climb very high (90K+) to obtain M3 or descend very low (72K) to avoid stall near these pressures. Avoid IAS over 460 or under 380 at cruise. I cannot stress enough that the most maintenance-free flights will have cruise speeds near 400KIAS (the middle of the model's stability range.)
END WEATHER PREP. PRE START PREPARATION CONTINUES...

PRESET THE AUTOPILOT to have AutoThrottle ENABLED, set initial altitude +10,000 AGL, 250 knots IAS (for low alt restriction) and 3500 ft/min climb rate. When not conserving fuel, higher climb rates can be used.
Note: The SR71 does not have an Auto-Throttle. This functionality is preserved in this model for the convenvience of the pilot. The extreme power level range the engines are capable of makes programming a smooth AT difficult. Although it works well in this model, it's not totally smooth.

Switch NavGPS switch to GPS (note: GPS mode disables ILS approach so you need to turn the switch back to ILS during automated approach.)
END PRE-START PREP

o Start-up-
If necessary activate the fuel pumps with control-shift-F4 or the fuel pump valves in the fuel panel. on the left of the main panel, click and HOLD each engine start button until ignition (apprx 22% RPM.) Alternatively, activate the autostart sequence with shift-e. The Chevy V8s will spool up loudly. Once the engine ignites, the TEB counter will lower by one (starts at 16) to indicate one shot of Triethylborane was used to start the engine.

o Taxi-
Move all control surface and visually verify correct operation. When engines have stabilized, start taxi not exceeding 20 knots ground speed. Avoid rough ground so as not to damage the gear or debris intake damaging the engines. Constant breaking will be necessary due to high engine idle RPM.

o Take-off:
Position into the wind, set the breaks and bring up the autopilot. Check elevator, aileron, and rudder trims for zero degrees.
Set the AP AT and IAS bug to 255 IAS.
Position the mouse over the IAS HOLD button to assist in rapid control changeover in flight.

Smoothly advance the throttle to 70% (full military.) Release the breaks and engage the Afterburner (shift-F4.) Smoothly advance the throttle to 100%. The TEB counter will drop another number to ignite the ABs. Be prepared to pull the throttle back soon to avoid EGT limits in hot weather or conform to any area speed restriction which might be in place.
Observe EGT temperature and do not advance throttle beyond 850C unless absolutely necessary. 900C can only be used for 2 minutes maximum and 950C has a 15 second limit. Note: At standard temperatures (50-60 degrees F) full throttle will rarely exceed 850C EGT.

Crossing 156 knots reduce throttle to apprx 85% to prevent over-shooting terminal area speed restriction of 250 KIAS.
At full weight rotate the nose steadily at apprx 205 KIAS to 10 degree pitch and hold until lift-off into a 1000 ft/min climb (down pressure will be required to prevent nose up.)
45K lbs fuel (22% CG) use 180 KIAS rotation speed.
On positive climb raise gear immediately. It will break above 360KIAS. Disengage AB as you near 240 KIAS for speed restriction.
Engage AP (Z) and tap Contrl-T to temporarily hold climb profile @ 1,500 ft/min, and click IAS speed hold 250 KIAS in the autopilot (when flying in restricted space.) Closing on 250 KIAS click ALT hold in the autopilot with the mouse. The 255 bug setting you set earlier will hold close to the 250 KIAS in restricted space.
Tap Cntrl-H to hold current heading.

Note: Clicking the speed hold with the mouse has a different effect than using the key combo Control-R.
When using the keys, the AT will be set to the CURRENT air speed of the plane. The mouse will set the AT to the TARGET speed set in the AP bug control.

At this point the plane will be under stable autopilot control in trimmed flight. As the speed reaches 250KIAS increase normal climb to 3500 ft.min. Max climb off the runway can initially be as high as 10,000 ft/min on full throttle/AB. Sustainable climb using 7000 ft/min is possible up to 24K ft.

o Terminal maneuvers:
Use ATC instructions or bring up the navigation aids (GPS etc) and navigate to intercept the 1st flight plan waypoint. Observe the 250KIAS speed restriction when flying near controlled airspace. Engage autopilot NAV mode to start GPS flight plan control. External control programs require staying in HDG mode.

Above 10K ft AGL, lower climb rate to 3000 ft/min and advance autopilot IAS bug to obtain 400 KIAS climb to next altitude target. Crossing 250KIAS engage Yaw Damper. Crossing 18K ft, reset altimeter to 29.92.
On long flights where fuel top-off is necessary, intercept the tanker altitude @ 28 - 35Kft.
Older tankers require 25K - 30K feet. In turbulence, use 350 KIAS for the sub-mach climb, otherwise, use 400KIAS. New tankers modified for the SR71 can use 34K - 35K ft.
Note1: 35,000ft and 350KIAS is the highest and fastest the plane can fly and still remain sub-mach (apprx M.97) 28,000ft and 400 KIAS is more typical providing M.95.
Note2: Max turbulent speed is 350KIAS so only use 400 KIAS at low altitude in calm conditions.

o Refueling:
Intercept the tanker between 280 and 305 KIAS. Under current model configuration, fuel top-off is typically filling ALL available tanks. When flying max range with take off COG at 22%, a COG over 24% will result in a warning. The warning will clear as soon as speed in the climb over Mach .9 is obtained. Each tap of the large red "FUEL" (refuel) gauge provides an increase of appx 10% - 12% fuel.
At typical tanking speed of @280KIAS, and full fuel, the attitude will be near 10 degrees.
Marginal military power at high pitch can be compensated by enabling AB on one engine.

Dipsy Doodle (modified for FS9):
After refueling, set AT hold for speed Mach .9, engage AB (or remaining AB if one side already enabled) and set climb rate to 2000 ft/min.
Between 30K-32K ft increase ATspeed bug to Mach 0.95. Passing M0.95 and 33Kft set AT bug for 550 and start a shallow descent through Mach 1.15. Passing 230 to 240 KAES (on the tripple gauge slowly increase climb to +2000 fpm. Continue climb adjusting Autothrouttle to hold KAES on the climb.
The "Dipsy Doodle" is designed to transition through high pitch drag around M1.05 - M1.15 as quickly as possible.

o Mach Climb:
While in turbulence, Mach Climb will use 350KAES. Normal climb:
1) Set required altitude in AP.
2) Set 500 KIAS in the AP bug to obtain initial speed of 450 KEAS on the tripple gauge.
3) 1500 ft/min when good climb speed is obtained. Can use 2000 at low weights and short distances.
4) Max climb (world record flight for instance) uses 3500ft/min initially.
5) Engage After-Burner (note: AB will stay engaged throughout flight until descent.)
Note: Throughout the climb until mach hold, the goal is to maintain 450+ KEAS.

COG:
At take-off the plane is tail heavy which assists rotation. Too high COG at take off makes it easier to have a tail strike from rapid rotation. During flight the aft fuel burns off 1st- slowly moving the COG forward for mach cruise. During approach and landing, normal fuel attrition will result in COG which is in the typical range for landing (unless the pilot has used unusual fuel loading.)

As speed increase stops or begins to drop, advance IAS bug to hold 400+ KIAS. When using Max Climb, keep the 440 KIAS bug setting until Mach hold is engaged. The goal is to hold as close to 400+ in the speed gauge as practical to avoid too-high pitch, yet avoid potential overspeed in high pressure and cold temps. Typical max bug setting on normal climb is 440 KIAS to avoid O-Speed.

----------------------- WARNINGS AND PROCEDURES: -----------------------

!!!! PITCH WARNING !!!!
Avoid pitches in the AI display over 5 degrees. At approx 5.5 degrees stall is imminent above Mach 3. WARNING!!!: DO NOT ALLOW PITCH on the Attitude Indicator to drop below zero above Mach 2. Temperatures warmer than -58 deg C and over 72K ft are marginal operation. Climb to cooler temperatures or hold present altitude, or descend to maintain pitch under 5 degrees. Structural failure will occur @ 505 KIAS.
-75 C Static Temperatures of -75 C or lower will reduce engine output to less than max rated power.
Deep Stall will begin above 60K ft and slower than 350 KIAS. It starts as a "twitchy" altitude hold where it appears the AP has trouble holding the altitude and the needle always sits just below the set altitude. I strongly advise not flying under 380 KIAS at or over M3.0.

PITCH TOO LOW PROCEDURE: Climb moderately and or slow to lower mach speed. Loss of control roll procedure (overspeed): - Immediately Disengage AB and idle throttle by disengaging MACH hold. - Attempt to climb. Try to avoid uncontrolled dive which will make the problem worse. If the negative pitch is caught early enough by slowing quickly, the plane will recover itself.

STALL PROCEDURE: - Reduce climb rate, level off, or descend as conditions require. Maintain highest safe mach. Do not exceed M3.35. When pitch drops to stable condition, maintain profile (no matter how long it takes) until a typical pitch of .2 to 4.8 degrees is obtained. Only then can climb be re-engaged. Note: Sometimes conditions combine to limit engine power AND provide excessive pitch. This will seem like a no-win as the temperature limits the engine so you cannot increase speed and lower the pitch. Descend or maintain altitude until stable flight is obtained.

!!!! ENGINE POWER WARNING !!!!
High pitches due to excessive climb rate, severe weather changes, or inattentiveness to power profile may result in loss of power at max throttle. Max throttle is typically @93% RPM at -68C static Air Temperature.
Too-high pitches will cause power loss.
Temperatures warmer than -58 degrees C or colder than -75 degrees C will cause power loss.
POWER LOSS PROCEDURE:
Level out or descend gradually until pitch and temperature permit power recovery. Avoid maintaining flight conditions where The auto-throttle stays at 100% when at mach cruise. In normal mach 3+ cruise engine RPM is between 83 and 87%.

!!!! Engine Overheat Warning !!!!
If the CIT temps are permitted to hold or exceed 428C continuously for 30 seconds or more, one engine will be commanded to fail. Each engine has a 50% chance of failure. A failed engine cannot be restarted. The non-failed engine will continue to operate. The rapid reduction in speed will prevent damaging heat in the remaining engine. With one engine operating on AB, you will need an initial descent rate of -3000 ft/min to keep the speed from going below 300 KIAS. When it no longer requires 100% power on the remaining engine to sustain 300+ knots you can look for the nearest runway with 7000 ft or more to land. This should occur between 65K to 70K ft. Depending on your fuel load, you should be able to find a runway up to 250 miles away.

!!!! OVERSPEED WARNING !!!!
Overspeed conditions are very dangerous and you only have seconds to react. When flying near the mach limits very slight changes in weather can bounce you over the edge without warning. M3.2 normally provides a safe buffer zone with 100 knots between both overspeeds and stalls. Overspeeds are caused by very high (non-typical) pressure jumps. The best speed is to set the Mach to provice as close to 400 knots as is practical.
OVER-SPEED PROCEDURE:
Disengage AB. Turning off reheat is the fastest way to react to overspeed but will cost you a TEB hit to restart. The result is a large power loss which helps slow down faster. If you don't want to use up TEB, a large manual pull back of the throttle will be necessary. If AB disengage is not enough, Disengage AT (shft-r) and idle the throttle. Avoid descent. Maintain altitude or climb will help prevent acceleration and increase your overspeed margin. Upon slowing to safe speed (do not slow below M 2.8) re-engage AB and/or AT (shft-r). Carefull attention to the spike position will be necessary with large speed changes.

!!!! Electrical Power loss and Dead Stick Landing !!!!
Dead stick landing after the loss of two engines has been simulated as well as loss of generator power to the battery. Many successful dead stick landings have been made from 70K ft and up to 200 miles from a runway. Longer distances are possible.
If the load on the battery is reduced to only necessary items, the battery will support the flight through landing.
If the battery fails, vital navigation equipment will remain functional:
Airspeed
Attitude
Altimeter
Vertical Speed
Radar Altimeter

------------------- END WARNINGS AND PROCEDURES -------------------

440 IAS in the AP speed bug is the maximum SAFE that should be used in the mach climb so a smooth mach mode switch-over can be obtained without over-speed.
o Mach Climb:
MACH MODE:
NOTE: FS9 does not show the whole digit 3 when the speed is over Mach 3. At Mach 3.0 it will indicate 00. At approx Mach 2.90 to Mach 2.95 switch autopilot to MACH. Observe these two things:
1) The speed hold bug in the speed gauge should be near the actual speed indication on the gauge.
2) The mach bug indication in the AP should read between .01 and .30 while the air speed gauge indicates Mach 3 or more.

Switch back and forth between IAS and Mach mode and increase-decrease IAS bug numbers until the mach indication reads .20 (typically while crossing Mach 3.01 on the IAS gauge. This will hold Mach 3.2. Use the same procedure to change Mach speed. Switch back and forth between IAS and MACH and change the bug while in IAS mode.
Note: It is POSSIBLE to switch to mach mode too long after transitioning to mach3 so when switching the indication hold is actually 4.2 or 5.2. If the difference between the speed hold bug on the airspeed gauge and the actual indicated airspeed is large, this might indicate you have accidentally advanced to the next mach range. This will cause an over-speed condition eventually. Lower IAS until you jump to the proper mach range. Note2: I find it easiest to keep the mouse over the autopilot speed numbers and use cntrl-R and cntrl-M to switch back and forth between IAS and Mach modes while refining the setting.

At max fuel load, climb rate is slowly decreased as follows (note: These are guides. Actual operation may vary depending on weight and weather conditions. This table is for conserve fuel usage.)
60K ft = 1800 ft/min
65K ft = 1500 ft/min
70K ft = 1200 ft/min
75K ft = 1000 ft/min
Last 1000 ft = 700 ft/min

Alternatively for conservative climbs, use the Concorde style "Cruise Climb" at 100ft/min above 60K ft.

Note: FS9 setting for max climb is Auto-Throttle set to 440 IAS, then manage the climb rate to keep the IAS gauge above 400 IAS as possible.

Engine Spike:
21 inches of total movement normally auto-controlled starting at mach 1.7.
This model is manually controlled and provides a maximum of 1% N1 improvement in efficiency at full retract (full flap deploy) into the engine.
Subsonic to Mach 1.7 = retracted-spike fully extended (F5)
Mach 1.7 to Mach 2.2 = position 1 (1 tap F7) (25%)
Mach 2.2 to Mach 2.7 = position 2 (1 tap F7) (50%)
Mach 2.7 to Mach 3.2 = position 3 (1 tap F7) (75%)
Mach 3.2 = position 4 (1 tap F7 full engine retraction-flaps deploy) (100%)
NOTE: At speeds of Mach 1.6 or above, leaving the spike out of configuration for an extended time will cause temporary loss of the afterburner and of engine, requiring each to be restarted. The functionality is as follows:
Below M1.6 and spike position is out for 15 seconds or more, the AB will be disabled if it is on. Restarting the AB will lower the TEB count by one for the engine that failed (each engine has a 50% change of failing.) There will be no engine shut-down below M 1.6. Once the TEB count reaches zero, another engine start or AB start is not possible, but the AB and engine will continue normally until shut down.
Above Mach 1.6, the spike out of config for 15 seconds will cause AB shut-down. If left out of config for 30 seconds, the associated engine which had the AB shut down will shut down causing loss of power. If the spike is corrected before the RPM reaches 22%, the engine fuel value will re-arm and the engine will attempt to restart itself. If an auto restart fails, the engine must be started manually.
The spike position gauge will change from white to yellow during the 1st 15 seconds prior to the AB timeout. At 15 seconds, the gauge will change to red and continue counting until the spike is placed back in correct configuration.

o Cruise:
This is the most stable and non-maintenance stage of the flight. Unless a weather condition causes one of the anomalies above, no action is necessary.
Your task is to manage speed and altitude to keep the pitch bug on the Artificial Horizon between the level and +5 indicators. You will also manage the intake spike to retract it at proper speeds. If fuel procedures were followed carefully, the fuel balance and attrition system will maintain controlled flight without intervention. Panel warnings will activate if COG or speed is out of limits for the flight profile.
Keep this in mind:
- Higher, colder air provides higher speed and more fuel efficiency at a cost of reduced total engine power.
- Lower, warmer air uses more fuel and heats the engine and surfaces.

Cruise Climb:
Nearing 60Kft. reduce climb in a profile called "cruise climb" to around 100ft/min up to the target altitude. It's not unusual to have to change altitude in small increments once reaching target altitude to optimize the flight for weather conditions. Crossing Mach 3.0 fuel rate will typically reach 40K - 44K lbs/hr. As you reach M 3.2, rates may drop to 36K-38K lbs/hr or less. Above M3.2 fuel rate will increase again. Occasional extreme errors in weather server data may cause extremely high or low fuel rates. It is suggested you use the Active Sky option: "Force Constant Route Pressure" and load your flight plan into AS to provide ultra-smooth pressure changes during flight. Force Constant Temperature will add a bit more weather predictability.

o Descent:
Note: At high mach speeds the pilot manual uses KEAS (Equivalent Air Speed) to compensate for errors due to air compression within the pitot tube. At standard pressure of 29.92 and 80K ft AES is about 70 knots slower than IAS so 422 KIAS would equal 350 KAES. The current panel does not support AES gauges. In the table below 350 KAES is the documented hold speed for the descent so you should use 422 KIAS.
Following information is simplified excerpt from Pilot Manual.

Descent Profile:
If cruise speed is below 422 KIAS, hold current mach.
in decent until passing 422 KIAS, then hold 422 KIAS.
DECSENT_PROFILE (83K)
The chart graphic above is converted into more FS friendly table below:
Distance
Land/Tanker
AltitudeSpeed
395/30890KftM3.2/422KIAS
325/23880M3.2/422KIAS
296/22574M3.2/420KIAS
248/14870422KIAS
215/11560422
180/8050422
163/6340401
150/5030180
Under 150 miles Set desc rate per desc calc gauge with approach target altitude set in AP alt
140/4025370

At 14k ft AGL, slow to 300 KIAS by setting AIS bug to 290. At 12K ft AGL, slow to 250 KIAS by setting IAS bug to 240. Within 40 miles of landing slow to 220 KIAS minimum turn speed.

o Terminal maneuvers and approach:
At light weight and slow, the model is very maneuverable. Final approach should use speeds as suggested by weight and approach chart near the top of this document. Typical terminal speed for base turns is 220 KIAS minimum.)

Normal landing weight is 10K lbs and base turn should be made @20 miles and 220 KIAS. When lined up reduce speed to 17k KIAS. At max weight, decel to threshold speed should be made at least 9 miles out. 10K lbs fuel can decelerate in @7.5 miles. 8 degree pitch is typical on the landing descent, 10 degrees on the AH over the threshold. Use shift-enter key sequence to lower the view to see the runway. shift-backspace to pitch up or SPACE key to recenter view to default. The Approach Auto-pilot will hold a steady glideslope with fuel weights up to 22,000 lbs.

In the current panel, target AOA is apprx 12 degrees on the gauge (which is actually close to the real AOA of 10 degrees. HI limit will be near 10 degrees on the AH. - Set decision height on the radar altimeter to 350 ft.
- Upon GS capture (when using AP APP mode) lower the gear passing - 5 ft/minute.
- Arm drag chute if there is little or no crosswind. An armed chute is indicated by the center changing from black to orange. If there is significant crosswind, operate the chute manually after the front wheels touch down.
- Between 350ft and 500ft take manual control (z key) of pitch, roll, and yaw and target the threshold with between 700-1000 ft/min descent.
- At apprx 150ft AGL flare to obtain minus 50ft/min or less and reduce throttle to idle at 10 ft after the key sequence control-r (to disengage AT control.)
On touchdown, chute will deploy on wheel contact WITH THROTTLE IDLE. Nose will drop slowly on its own. Use stick back pressure near the bottom of the drop to lessen the nosewheel impact. On cross wind landing, deploy the chute manually after front wheel contact.
- Begin gradual breaking @ 65 knots ground speed.
- Around 30 knots jettison drag chute (/)
Taxi to parking not exceeding 20 knots ground speed. Shut down engines using contrl-shift-F1 or fuel panel switches.
Note: The high RPM of the engines may result in nearly constant breaking at low weight typical at landing. If breaking is a problem, one engine can be shut down. However, this causes a lot of steering to compensate for the induced yaw. It's a trade off.

Real world tanker descent (assumes M3.2 80Kft):
If slower than 422 KIAS, use Mach hold on initial descent. Otherwise use 422 KIAS.
-Start descent 325 miles from runway. Tanker is expected 100 miles this side of runway.
-Set descent alt (target) in AP for 29K ft.
-Gradually set initial dec rate to 4500.
-Crossing -2500 ft/min on VSI disengage AB.
-As air speed in mach hold approaches 425,
set 375 in the AT bug and adjust as needed to hold 420 - 425 until 40K ft. Use SPEED Warning gauge to help you keep it in check. -Observe dec calc and adjust dec rate so calc and target runway distance match crossing 70K ft.
-At 70K ft set AP alt for 7000ft. Keep watch on the speed and adjust dec rate to keep the calc reading near or just over the distance to runway. Try to cross 50K ft with 180 miles to go.
-At 50K ft set target alt on the AP for 4,000ft. Adjust dec rate to cross 30K ft 150 miles from runway. Target crossing 40K at 163 miles. You should be -6000 to -7000 ft./min by now.
-At 40K ft, set AT bug to obtain 400 KIAS and target crossing 30K by 150 miles.
-At 30K target crossing 25K by 140 miles. Set AT to obtain 370 KIAS.
-Within 100 miles of runway, adjust dec rate so calc display is 20 miles lower than distance to runway. Maintain this difference for remainder of approach to runway.
-At 30K ft, set AT bug to obtain 370 KIAS.
--- If using tanker, start rendezvous operations. ----
-At 25K ft, set target alt to Rny approach altitude.
-@ 50 miles from runway and/or 14K ft, set AT bug
to obtain 300 KIAS crossing 12K ft.
-At 12K ft, set AT bug to obtain 250 KIAS by 10K ft.
-by 30 miles from runway, be slowed to 220 KIAS minimum maneuvering speed.

PROCEDURE SECTION COMPLETE

Some interesting facts:
The SR is composed of Titanium and Composite (plastic) materials. The landing gear is the largest piece of titanium ever forged in the world. The United States did not have enough Titanium to build the fleet and ironically, we bought the needed Titanium from Russia.

50 Blackbird airframes of various designations were built.

The SR-71's fly at 33+ miles per minute (1,980 MPH/1,722+ knts) or 3,000 feet per second or faster than a 30-06 bullet.

Each SR-71 cost 33 million to build and $1 million/mission to launch.

Aircraft skin temperature can reach 800 deg F.

Full AB thrust test stand exhaust flame apprx 30ft long producing 311 deg F temp and 150 knot winds 100 yards behind the engine. Another jet engine is used to push hot, super sonic air into the intake.

The cameras can photograph a golf ball on the green from 80,000 feet. They can survey 110,000 square miles of the Earth's surface per hour.

In 1981 Kelly Johnson announced that the SR-71 had over 1,000 missile launches against it, but none successful.

Pilots in a pressure suit can lose up to 5 pounds in a four hour flight.

The SR71 nickname Habu is the name of a Cobra snake in Okinawa, Japan. Apparently it's not normally aggressive to humans but has a nasty bite. Because of the sleek "hooded" appearance of the Blackbird caused by the chine, the Okinawan's claimed it looked like a Habu snake. Thus the nickname. Additionally, SR-71 Crew members are called Habu's.

The SR-71 flew for 17 straight years (1972-1989) without a loss of plane or crew. Of the 50 variants produced, 19 crashed with no loss of US Air Force crew.
One crew was lost launching a drone in an A12. The recon officer drowned in his chute. I have heard another accident related to unbalanced engines at cruise causing a breakup and loss of the recon officer.
The Seattle Museum of Flight in addition to the drone-mounted A12 has the nose of a crashed SR71 on landing at Kadena when the front gear collapsed. The rest of the plane burned.

478 total people have flown the Blackbirds. More people have climbed to the top of Mount Everest. Last flight of a military SR71 into Beale AFB for display: 1997 http://www.wvi.com/%7Esr71webmaster/sract%7E1.htm NASA used one of its two SR aircraft for research on the LASRE aerospike engine project as late as 1998:
http://www.nasa.gov/centers/dryden/history/pastprojects/SR71/Lasre/index.html NASA/DRYDEN documents the last flight of the SR71 as 1999: http://www.nasa.gov/centers/dryden/news/FactSheets/FS-030-DFRC.html

Program Info:(as of Jan 1990) Source: http://www.blackbirds.net/

* Total Flight Hours:...........53,490
* Total Mach 3+ Time:........11,675
* Total Sorties:.....................17,300
* Total Operational Sorties:....3,551
* Total Operational Hours:...11,008
* Total Air Refuelings..........25,862
* Total Crew Members:............284 (includes NASA and USAF Crews checked out in AC)
* Cumulative Hours by Crews:
o 300 Hours.....163
o 600 Hours.......69
o 900 Hours.......18
o 1000 Hours.......8
o 1392.7 Hours.....1

Some historic SR71 bases or refuel/training sites:
EGUN Mildenhall England (main base)
RODN Kadena Okinawa Japan (main base)
KBAB Beale Air Force Base California USA (main base)
KEDW Edwards Air Force Base California USA (Dryden)
(also near Lockheed Martin Skunkworks) in Palmdale KPMD
KSKA Fairchild AFB Spokane WA USA (training)
Note: Most flights out of Palmdale were operated by CIA and had differing procedures from the USAF.