Typical AOA at the above speeds and weights are 9 to 10
degrees, not to exceed 14 degrees (tail strike.)
Flight AOA Limits:
Max below 25K ft = 18 deg
Max Subsonic 25K+ ft = +10 deg
Max Supersonic 25K+ ft to 70K ft = +8 deg
Max Supersonic 70,000+ ft
= +6 deg
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
Min chute Jettison Speed: 55 KIAS
Max Sub-Mach Climb to Cruise:
Full Stop Break Release
to 24K ft in three minutes.
Temperatures between -55 to -70 C:
Design Mach Speed = 3.2 (above 35Kft)
Maximum Operational Mach = 3.35
Overspeed Mach =3.45
Maximum Indicated Air Speed
= 559 KIAS, 500 KEAS.
Max Safe Altitude = 85Kft (without special
Max Rated Altitude = 92K ft (can go higher when weather and weight 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 3.0
Min Supersonic Airspeed = 310 KEAS
Note: Descend rapidly if the weather system causes
a sudden drop in EAS 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)
Ground Lift effect: Within 30 ft.
Peak Aerodynamic Pressure: Apprx 670 lbs/sq ft (Dypsey Doodle Climb 450 KEAS through 35K ft.)
Normal Alt- 25K - 35K ft (35K feet with latest tankers.)
AOA 3 deg low fuel
AOA 6 degrees full
Typical distance between tanking: 2000
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
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)
(mach 3.0 @85Klbs gross weight)-
-53.9 (-52.8 FSX ISA)
338 model calibration
Nominal Inlet Temperatures (Mach 3.2 20K lbs fuel)
350 (typical Cruise)
380/Max: 427C (801F)@ M 3.38
Idle: ~430C @ sea level (typical)
Max start temp (idle) = 565 C
Normal Cruise Range: 780 - 820C
Continuous Limit: 830C
Emergency Zone = 825 - 845 C up to 15 minutes
Red Zone: 900 C up to 2 minutes
950 C up to 15 seconds.
Modeled MAC in FS2004 = 51 ft (wing + forward fuselage chine).
Typical range: Forward- +17% to Aft- +
Ideal Take off: 17 % (Published), Typical: 20%
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:
Ideal Landing: +21.0 to +22.0
Max at Mach 3.30 = 24.4% MAC
Trim Limits:Subsonic level=-1.5 deg nose
Supersonic level: Min=+0.5 @ M2.6 (normal 3.1 at full
Max=-1.5 @ 25% COG (normal 0 at Mach 3.0 near 24% COG.
Mach 3 Environment Temps:
Interior: 300 deg
Nose: 800 deg F
Windshield: 600 deg
Exhaust: 1,200 deg F (649C)
Min safe operating = 35 PSI
Normal = 40-60 PSI
Fuel Pressure: 7-9 Psi
Normal = 2200 - 3000 psi at or above 3000 Engine RPM
Reduced Control = down to
1500 RPM Control Failure = below 1500 RPM
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.
G Load Limits:
Mach 2 and Less (below 50K ft): -.2 to
Mach 2 and less (above 50K ft): -.2 to 2.5
Mach 2 to 2.6: -.1 to +2.0
Mach 2.6 to 3.2: -.1 to 1.5
Min Airspeed Restrictions:
Supersonic: 310 KEAS
Subsonic and >= 25 Kft: 300 KEAS
Subsonic and < 25 Kft: 145 KIAS
Pitch Trim: The model under ordinary fuel and speed operation and auto-pilot control will conform to the following flight trim settings after take off with 66K lbs fuel:
This general overview of technique for flying this aircraft in
FSX is not real-world but based on manipulating the sim to
obtain consistent results. Unrealistic weather conditions strongly
affect performance. The details here are also provided as checklist
and reference items within the panel Kneepad feature. New for sr2012Updt1c are htm checkist and reference files elliminating the problems the previous text files produced.
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
To provide a wider performance margin on take off
in case of an engine loss, the Air Force flew the SR-71 with one
of three fuel loads:
45, 55, or 65K lbs.
If using SFP or
NAV3, range and fuel estimating should be close using the
(EDITED for update sr2012Updt1b) Note: The SR71 is capable of fuel balancing automatically for the entire flight flight and approach. Automatic fuel tank selection and tank attrition schedule built into the model simulates the auto transfer system AS LONG AS you load the tank percentage below on the ground and left and right tanks are balanced.
The balancing system is in auto mode when the FORE AFT pump switch is in the center (AUTO) position and the Fuel Annunciator PUMP REL is off.
Easy Rule of thumb:
To set typical
take off weight of 45K lbs, set all the tanks in the FS fuel menu
to 56%. This will provide a COG close to 20% for take off. Any COG
between 19% and 22% is acceptable for take off or landing.
set 55.6K load: all tanks 69%
To set 66K load: all tanks 83%
Warning: There are EIGHT(8) fuel tanks in the FS fuel dialog. Failure to set ALL of them to the same percentage may cause the auto balancing system to provide less than optimum performance. This system of setting all the tanks to the same percentage was adopted to make fueling the SR-71 simple for the pilot even though the CG system is very complex.
Detailed explanation of this model's fuel balancing system.
1 hour or less than 1000 miles: Use 45K fuel load.
Up to 2 hours or 1000 to 1500 miles: Use 55K fuel load.
2 to 2.5 hours or 1500 to 2500 miles: Use 66K fuel load.
3200+ miles: Full fuel afer air refeuling
Do not try to take off with full fuel loads. Although it's possible, the potential for problems and the sluggish performance is not worh it. Unless you are flying over 3000 miles, you are not going to use all that fuel anyway.
FS Fuel Dialog:
Ltip = Tanks 1 + 1a
Rtip = Tanks 1 + 1a
Lmain = Tank 3 L
Rmain = Tank 3 R
Cntr = Tank 2 Foward Trim
Cntr2 = Tanks 4 + 6a Rear Trim
Laux = Tank 5 + 6b
Raux = Tank 5 + 6b
Fuel distribution is as follows
< NOSE to TAIL(111ft)
1 = 2300 lbs
2 = 3400 lbs
4 = 2400 lbs
5= 1900 lbs
Min Landing Fuel Weight: 5000 lbs.
These tank assignments and positions are based on FS2004/FSX built-in default tank attrition schedule which chooses the order in which tanks deplete until empty. A complex system of tank switching at certain capacities enhance the attrition for optimum CG and trim near Mach 3 and above.
Habu pilots considered 60,000+ lbs fuel weight a "heavy" jet. At the typical take off weight 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 the default loads of 45K, 55.6K or 66K lbs (depending on when you can
intercept the tanker) and plan on an air refuel.
Occasionally, near the end of long flights after refueling, the balancing system may allow the CG to move forward prematurely (although it causes no harm.) If the pilot wishes to assist the system to hold 25% longer at cruise, follow these steps:
1) In the Fuel Annunciator, click the "xFEED ON" switch so the xFeed in the Fuel Annunciator lights up. This prevents the system from using tank switching mode and the tanks will empty symmetrically per FS's internal tank logic. Note: Even when the XFeed ON switch is down (off) the system can still use crossfeed, it's just not forced on all the time.
2) At the bottom, click "PUMP REL" so it lights up. This disables the automatic balancing pump so when you operate it, it will not try to correct you and will retain your actions.
3) In the Fuel Panel, operate the fuel pump by clicking the top or bottom (bottom to move fuel aft and increase the COG.) Clicking the center stops the pump.
IMPORTANT: You should avoid pumping the center tanks below where the text quantity changes to yellow. At that point, you should stop manipulating the system and change the two items above back to the unlit indications.
END FUEL PREP.
The SR71 is sensitive to pressure and temperature more than wind speed because of the high altitude. Near the flight limits large pressure changes can throw the flight model well beyond its operational limits. Pressures over 30.10 inHg are problematic because they force you to fly very high (which can be fun, but increasingly risky.)
Recent retail versions of FSUIPC for FSX provide temperature, wind and pressure smoothing which greatly enhance the flyability of this aircraft when using Jeppeson weather. Very low presure will force the pilot to fly altitudes ~74K ft. Active Sky Next is the preferred weather source and does not require FSUIPC for smoothing.
Note: Active Sky Next uses SimConnect bypassing FSUIPC completely. FSUIPC is not needed at all for weather communication or modification.
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. 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.
80,000ft should be used for flights East and 79,000 for west.
Although the model supports flights up to 85K ft (normal limit is 82K ft) with pure Jeppeson-only weather source, unstable weather over coastal transition boundaries (300 -
500 miles from land crossing over large bodies of water) may cause highly unstable flight. Engine power is reduced by
periods of extreme off axis air flow. The payware version of FSUIPC has a wind smoothing feature which helps reduce rapid wind axis changes but as mentioned, not be used with Active Sky Next.
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 FSX 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 tabbed graphical display.) This lets you see all the current weather settings at a glance without
scrolling or tabbing.
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 without switching to the
desktop. As you get more experienced, you will come to expect certain IAS readings at certain altitudes.
This panel has a special enhancement to the Altimeter to display relative pressure changes.
Higher or lower than normal air speeds at Mach 3.2 are an
indication you are flying in unusually low or high pressure. This can help the pilot take pro-active measures to reduce the effects of pressure changes.
Active Sky Next plan and Briefing:
By far the most useful tools in ASN for flight planning are the Flight Plan load, Briefing, and Map Insert waypoint features.
Load a plan into ASN and with these settings in the flight plan aircraft attribute fields, refresh the plan and inspect the briefing screen with TOC/TOD checked:
Climb FPM: 1920 / Climb TAS: 900
Descent FPM: 2900 / Descent TAS: 700
Cruise TAS: 1780
DUSKI: (Calculated flying altitude 68200 feet)
- ETA in 50 minute(s) 43 second(s)
- Expected weather conditions: PKWA 242040Z AUTO 07016KT 10SM SCT020 SCT030 29/23 A2981 RMK AO2 T02860232
- Expected winds: 21/24
- Expected temperature: -79.62 celsius
By using the map and inserting waypoints, you can create additional temperature, wind and pressure checkpoints without changing your navigation program.
TOC: (Calculated flying altitude 80000 feet)
- ETA in 54 minute(s) 52 second(s)
- Expected weather conditions: PKMJ 242051Z 05012KT 10SM VCSH FEW016 SCT050 BKN140 28/25 A2984
- Expected winds: 321/7
- Expected temperature: -68.97 celsius
JMROY: (Calculated flying altitude 80000 feet)
- ETA in 1 hour(s) 10 minute(s) 36 second(s)
- Expected weather conditions: PHLI 242029Z 05020G26KT 10SM BKN020 OVC029 24/21 A3019 RMK AO2 PK WND 05026/2028 RAB04E14 P0000 $
- Expected winds: 264/23
- Expected temperature: -60.63 celsius
TOD: (Calculated flying altitude 80000 feet)
- ETA in 1 hour(s) 32 minute(s) 47 second(s)
- Expected weather conditions: PHLI 242029Z 05020G26KT 10SM BKN020 OVC029 24/21 A3019 RMK AO2 PK WND 05026/2028 RAB04E14 P0000 $
- Expected winds: 264/23
- Expected temperature: -60.63 celsius
SYVAD: (Calculated flying altitude 74100 feet)
- ETA in 1 hour(s) 33 minute(s) 39 second(s)
- Expected weather conditions: PHLI 242029Z 05020G26KT 10SM BKN020 OVC029 24/21 A3019 RMK AO2 PK WND 05026/2028 RAB04E14 P0000 $
- Expected winds: 264/23
- Expected temperature: -65.10 celsius
Using the above information you can see this flight would provide unusual temperatures for the SR where the air is colder than the recommended -75C during the climb.
NOTE on PRESSURE:
In practice, pressures during M3+ flight OVER 1024.4mb
(30.25Hg) or UNDER 997.3mb (29.45Hg) are problematic. You can expect to have to climb very high (90K+) to obtain M3 or descend very low (72K ft and under Mach 3) to avoid stall near these pressures.
Avoid IAS over 500 or under 380 at cruise. I cannot stress enough that the most maintenance-free flights will have cruise speeds near 400KIAS/352KEAS (the
middle of the model's stability range.)
END WEATHER PREP. PRE-START PREPARATION CONTINUES...
These procedures are also available in the onboard kneeboard checklist.
PRESET THE AUTOPILOT to have AutoThrottle ENABLED, set initial altitude (usually 10,000 AGL to 28,000) 255 knots IAS on AP bug (for low alt restriction) and 4500 ft/min climb rate. When using normal unrestricted climb, set initial alt to 28K ft and AT IAS bug to
450 KIAS. This will hold close to 400 IAS (350 KEAS.)
Alternatively, use the KEAS HOLD in the Refuel or Autopilot panels to hold climb and decent speeds.
Switch NavGPS switch to GPS (note: GPS mode disables ILS
approach so you need to toggle the switch back to NAV during
automated ILS approach.)
END PRE-START PREP
With brakes, battery and APU on, click 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 (from 16) to indicate one shot of Triethylborane was used to start the engine.
Move all control surfaces and visually verify correct operation. When engines have stabilized, start taxi not exceeding 20 knots ground speed or 40 MPH. Avoid rough ground so as not to damage the gear or debris intake damaging the engines.
Frequent breaking will be necessary due to high engine idle RPM.
Warm surface temps and frequent breaking will activate the yellow "TIRE" warning.
o Position and Run-Up:
-Position on the runway into the wind, set the parking breaks and bring up the autopilot.
-Inspect all gauges and switches for correct position for take off. Wait for yellow TIRE warning to extinguish.
-Activate Pitot Heat and also De-Ice if you are passing through freezing clouds on the way up.
-Check Roll, Pitch and Yaw trims for zero position. Operate pitch roll and yaw stick controls and observe they all move to maximum positions (100%) and return to zero.
-Tap the numpad-5 key (with numpad off) to center your control inputs.
-With breaks set, smoothly advance the engines to full
military (80% green) for correct operation. IGV lights should illuminate. Return throttle to idle. IGV lights should go out.
-Set decision altitude bug to 350 ft on the radar altimiter.
-Test proper IAS hold operation by briefly clicking on the IAS hold in the AP. The bug should stay where you placed it. If it moves, reset it. Next time you activate it, it will not move. Set throttle back to idle.
-Double check everything.
KIAS vs KEAS:
Equivalent Air Speed is used for high speed flight. You
will see KIAS (Indicated Airpseed) or KEAS used in specifications and procedures depending on documentation available or whether the flight mode is subsonic or supersonic.
Set the AP AT IAS bug to 255 KIAS for restriction or 464 KIAS (to obtain an initial 400 KEAS) non-restricted climb.
Preset your desired initial climb rate.
This is typically between 7000 and 10,000 ft per min. (The
default is 1000.)
-Smoothly advance the throttle to 80% (full military.)
-When bright amber IGV lights come on, release the breaks and after reaching full military power, engage the Afterburner (shift-F4 in standard and Deluxe.)
In AccPack, advance throttle beyond 80%.
Throttle position numbers will change from green to white, REHEAT gauge lights and the TEB counter will drop another number to ignite the ABs.
-(optional:) Activate full take-off power (TO/GA) by tapping the key combo Shift-Alt-G
or click on the left throttle position number next to the top of the throttle (the numbers will change to orange or dissapear.) Using this feature will help prevent over speed on the engines.
-Passing 156 knots (speed check) you should be over half way through your roll distance. 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. If your climb is unrestricted, keep the throttle at 100% (or TO/GA mode) through the initial climb.
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. Normally, the de-rich system will prevent exceeding 960C on take off.
Note: At standard temperatures (50-60 degrees F) full throttle will rarely exceed 850C EGT.
Note: Very warm surface temps will limit climb rate.
-Crossing 156 knots Indicated during roll, reduce throttle to apprx 85% to prevent over-shooting terminal area speed restriction of 250 KIAS when in ATC control. Otherwise, when non-restricted stay in TOGA mode.
-At full weight (66K lbs fuel) rotate the nose steadily at apprx 205 KIAS to 10 degree pitch and hold until lift-off into a 2000
ft/min climb (strong down pressure will be required to prevent nose up.)
-When using 45K lbs fuel (Normal loading) use 180
KIAS rotation speed.
-On positive climb raise gear immediately.
Gear will break above 300 KEAS/330 KIAS. Retain AB through
-Engage AP (Z) and tap Contrl-T to temporarily hold
climb profile @ 1,500 - 2000 ft/min and click IAS speed hold 255 KIAS in the autopilot (when flying in restricted space.) Closing on 250 KIAS (restricted) disengage AB and click ALT hold in the autopilot with the mouse. This will happen very quickly!!! The 255 bug setting you set earlier will hold close to the 250 KIAS in restricted airspace.
-Tap Cntrl-H to hold current heading.
-Unrestricted, you must first obtain an initial
airspeed of 300+ KIAS while at a low climb rate. Continue to climb on TO/GA and set best climb rate to hold as close to 400 EAS through to Mach 0.9.
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. Resticted: As the speed reaches 250KIAS increase normal climb to 3500 ft.min.
Unrestricted: Max climb off the runway with gear up can initially be as high as 10,000 ft/min on full throttle/AB after passing 300 KIAS using Autopilot VS. Sustainable climb using 7000 ft/min is possible up to 24K ft in normal temperature conditions.
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.
-Engage Yaw Damper (Surface Limiter) above 330 knots Indicated (LIMITER in the annunciator.)
-Crossing 18K ft, reset altimeter to 29.92. Crossing Mach .85 set Mach Hold 0.90 for cruise to tanker circuit. Otherwise, hold M.9 for your cruise-climb to unrestricted Mach climb area.
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 KEAS 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 350KEAS so only use 400 KEAS in calm conditions.
Intercept the tanker between 280 and 305 KIAS or Mach 0.85 (whichever is slower.) Under current model configuration, fuel top-off is typically filling ALL available tanks. When refueling 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. Using the supplied refuel gauge, enable the RDY/DISC button so "0000" is displayed on both top and bottom rows of numbers and click the "Air Refuel" switch.
The rate is @6500 lbs/min, all tanks simul-filled 5-10 minutes at 56-70 psi. The refueling gauge operation is also discussed in the Special Gauges section above.
At typical tanking speed of @280
- 300KIAS, and full fuel, the pitch attitude will be around 10+ degrees.
Note: In reality one tanker could not hold enough fuel for a full SR-71
replenish so required a second tanker to obtain the last 5000 lbs. This is not enforced in the model.
Marginal military power at high pitch can be compensated by enabling AB on one engine and using differential engine control to compensate for yaw.
o Dipsy Doodle (modified for FS9/FSX):
This is the most common technique used to accelerate into the mach climb after refueling to a heavy condition which helps to transition through the high drag of mach 1 at low pitch. 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.
If you have refueled at 35K ft, set Mach hold to 0.95.
Between 30K-32K ft increase AT speed bug to Mach 0.95. Passing M0.95 and 33K ft or above set AT bug initially for 530 (for 450 KEAS climb) or 470 (for 400 KEAS climb) and start a -2000 descent through Mach 1.15. Do not descend below 29,000 ft.
Passing 390 KIAS when using 400 EAS climb
increase climb to +2500 fpm. When using 450 "Normal" schedule, set IAS hold to 530 KIAS and when crossing 450 KIAS set climb to +2000.
As EAS in the Triple gauge crosses 400 or 450 without blinking, engage EAS hold.
When using 400, set climb rate to +3500. When using 450, set climb rate to +3000.
o Mach Climb:
There are two common climb speed "schedules" used:
450 KEAS which is the "normal" high speed climb into a high risk area after tanking. Fuel burn rates are fairly high reaching 40-44K lbs/hr at Mach 3. On a 1.5 hour flight, around 2000 lbs more fuel will be used than the 400 EAS schedule. This profile gets you over the mission area at high speed, but low altitude again soon for re-tanking. Climb discussions in most books about the SR mention this profile as it's commonly used for incursions close to enemy recon targets.
400 KEAS is used when longer range is needed between refueling. Mach 3 fuel rate is closer to 38K lbs/hr. This profile gets your plane higher sooner, but establishes cruise at a lower initial speed. The world record flights between Beale and Farnborough used a profile similar to the 400 KEAS schedule between refuel tracks.
When flying light (45K lbs fuel or less) and refueling is not used, it's possible to start the climb without the Dipsey Doodle.
Starting from level at Mach .95, engage the AB and set the AT bug to 470 (to obtain 400 KEAS) or 530 (to obtain 450 KEAS) and ease into the desired climb rate starting shallow passing 380 KEAS or 420 respectively. As in the Dipsy Doodle climb, the initial climb target is 74K feet at Mach 3.0.
Adjust Mach speed using this procedure: How to set Mach Hold over 3.00 in FSX
At high fuel loads and 450 KEAS climb speed, climb rate is slowly decreased as follows:
Note: These are guides for 80K ft cruise. Actual operation may vary depending on target altitude, weight and weather conditions.
60Kft = 1500 ft/min
70Kft = 1200 ft/min
75K ft = 1000 ft/min
78K ft = 700 ft/min
Within 2K feet of target = 500 ft/min
Alternatively for more fuel savings, use the Concorde style
"Cruise Climb" at 100 ft/min above 60K ft qhwn over 50K lbs fuel. You should cross 74K ft at Mach 3.0. As the fuel rate per engine drops below 19K lbs/hr, gradually increase mach speed until the desired speed and altitude is reached. The 400 KEAS climb profile can use more aggressive climb rates than the 450 KEAS profile. Cruise Climb can also help get through rough weather areas where a slow increase in speed and altitude is much better tolerated than blasting up to target altitude and speed and trying to hold it while encountering extreme weather changes. According to one source, cruise climb was used 99% of the time by SR pilots.
Note: AP initial IAS bug setting for max climb and normal 450 EAS in Auto-Throttle is 530 IAS, then engaging KEAS Hold crossing 450 KEAS.
While in turbulence, Mach Climb will use 350 KEAS.
High Speed Climb:
1) Set required altitude in AP.
2) Set 530 IAS in the AP panel and while climbing ~ +2000 ft/min, click EAS Hold to capture initial speed of 450 KEAS on the triple gauge for the 450 KEAS climb profile. Increase climb rate to +3000 ft/min after capturing the 450 EAS hold.
3) Beale to Farnbourough world record flight uses 400 KEAS and 3500ft/min initially for the first two Mach 3+ cruise legs, then 450 for the last leg after refueling past the Canada East coast.
4) Engage After-Burner (note: AB will stay engaged throughout flight until descent.)
During climb the pilot manually sets the Aft Bypass Door positions to keep the Foward bypass Doors within their correct ranges. The foward doors maintain the correct pressure in the front of the engine by opening up and bypassing air past the intake. If they open up too much, excess nacel drag is created. Move the aft doors on this schedule:
Take off: Closed
Mach 1.7: Position A
Mach 1.9: Position B
Mach 2.6: Position A
Mach 3.05: Closed
There are times during cruise the pilot may need to move the bypass doors between Close, A or B. This is discussed in the section for the Aft Inlet Bypass Doors gauge.
At take-off the plane is fairly evenly balanced.
Too high Center of Gravity at take off is more likely to have a tail strike from rapid rotation. During flight the #1 tank fuel burns off first- slowly moving the COG rearward for mach cruise.
During descent, approach and landing, normal fuel attrition and automatic tank switching will result in foward moving COG for landing (unless the pilot applied unusual fuel loading.)
If you want to manage the CG manually, three controls are provided: Pump Release, xFeed, and Fuel pump Fwd, Aft. This is a failrly complex procedure. Auto is recommended.
400 EAS Hold: As you approach Mach 2.83 at near 74K ft, engage Mach hold M 3.0. I use 3.05 in the bug to prevent dropping below M3.0 in slight turns.
Continue shallow climb and watch fuel flow. As flow drops below 20K lbs/engine, slowly advance Mach hold to stay near 20K lbs/hr until desired speed is reached.
Note: When 450 KEAS Hold is used, the EAS Bleed schedule starting at Mach 2.6 will automatically engage reducing the speed gradually to Mach 3.0 near 71K ft without pilot intervention. You can see the current bleed target in the AP panel EASH display.
Nearing 60Kft. reduce climb in a profile called "cruise climb" to around 100ft/min up to the target altitude. It's not unusual to change altitude after reaching cruise to optimize the flight for weather conditions. Crossing Mach 3.0, total initial fuel rate may be near 40K - 44K lbs/hr. Closer to Mach 3.2, rates may drop to 36K-38K lbs/hr or less as fuel depletes. Above Mach 3.2 fuel rate will increase again due to friction. Occasional extreme changes in weather server data may cause much higher or lower fuel rates.
WARNINGS FAILURES AND PROCEDURES: -----------------------
!!!! PITCH WARNING !!!!
Avoid pitches in the AI display over 5 degrees.
At apprx 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 @ 520 KIAS.
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 310 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. You also risk Unstarts and compressor stalls the closer to 300 KIAS you get.
AERODYNAMIC STALL PROCEDURE:
- Reduce climb rate, level off, disengage heading or nav hold. Descend as conditions require to increase speed as fast as possible. Maintain highest safe mach. Do not exceed M3.45. When pitch attitude drops to stable condition,
maintain profile (no matter how long it takes) until a typical pitch of .1 to 4.8 degrees is obtained and 100% throttle is no longer required to stay above stall speed. 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. If the problem is caused by too-warm temps heating up the CIT and EGT, it's often best to avoid acceleration for a while. This will help the engine cool enough so you can begin a moderate climb into cooler air.
In ASN, the stagnant temperature of the tropopause starts at 49K ft and begins to get warmer above 65K ft.
ENGINE COMPRESSOR STALLS (no unstart lights:)
- Caused by:
1) Excessive AOA during climb (see specs section.) Reduce climb rate, level out, or descend rapidly.
2) Airspeed too low (below 350 KEAS) during descent rates greater than 1500 ft/min. Increase descent until faster than 350 KEAS.
Restart engine. Tap Shift-Cntrl-F4 if the first auto-start sequence fails. The auto-start sequence will usually try three times before giving up.
If you continue to have trouble starting engines, check the Fuel Switches on the Fuel and Oxygen Panel.
- Caused by improper spike position, decelerating too quickly while above Mach 1.5, Hard banking turns, or stalling the aircraft below 300 KIAS while above Mach 3.0.
Place spike in proper position (or return to AUTO [DOWN].) Continue to monitor for correct position during rapid deceleration. Reduce climb, level out, or descend rapidly (-7000 ft/min or more)
to build speed above 350 KEAS.
Wait for auto-restart sequence. If auto-start fails, hold start button on main panel until ignition. Alternatively, press the key sequence Contrl-E.
Historically, engines could not be restarted until descending and decelerating below Mach 1.7. This limitation is not emulated at this time but may be in the future. Unstarts will not happen below mach 1.5. but compressor stalls can occur from excessive bank turns at low speed.
If you continue to have trouble starting engines, check the Fuel Switches on the Fuel and Oxygen Panel.
!!!! 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.
Too-high pitch may cause power loss.
Temperatures warmer than -55 degrees C or colder than -75 degrees C may 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, throttle is between 96 and 98%.
!!!! Engine Overheat Warning !!!!
If the CIT temps are permitted to hold or exceed 428C continuously for 30 minutes or more, one engine will be commanded to fail. Each engine has a 50% chance of failure at this temperature. A failed engine cannot be restarted. The non-failed engine will continue to operate. The rapid reduction in speed and temperature 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 100% power on the remaining engine to sustain 300+ knots is no longer required you can look for the nearest runway with 7000 ft or
more to land. This sustainable power profile should occur around 60K ft and lower.
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 cruise technique is to hold close to 350 KEAS. 450 KEAS climb schedule is the most likely area where overspeed will occur as the EAS is just over 500 at certain altitudes. The KEAS hold button has the best capability to prevent overspeed on the climb. When flying using normal procedures and schedules, overspeeds are very unlikely uisng the Hold feature.
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 (shift-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 (shift-r). Careful 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 during testing. 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
------------------- END WARNINGS FAILURES AND PROCEDURES
NOTE: At speeds of Mach 1.6 or
greater, 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 which costs two shots of TEB.
This model is automatically controlled above Mach 1.6 and provides @1+% N1 improvement in efficiency at full retract (full flap deploy) into the engine. These are the settings should you descide to use the spike mode knobs in the Manual switch position (knobs facing right):
Subsonic to Mach 1.69 = spike full forward zero inches (F5)
Mach 1.7 to Mach 2.04 = 1 - 6.4 inches
Mach 2.05 to Mach 2.42 = 6.5 = 12 inches
Mach 2.43 to Mach 2.75 = 13 - 19.4 inches
Mach 2.76 to 3.10 = 19.5 - 25 inches
Mach 3.11+ = 26 inches
(F8 full engine spike retraction)
Ideal Cruise Summary:
After switching the AP
AT bug to Mach Hold at Mach 3.0, monitor the engine fuel rate. As the rate crosses 19K lbs/engine, slowly advance the mach hold or IAS
to obtain the desired cruise speed for the remainder of the flight. Ideal fuel rates should be near 18K lbs/hr per engine. Be
prepared to alter the cruise speed and altitude if changes in weather cause the plane to fly near the documented limits of 558
KIAS max or slower than 310 KEAS and/or max 427C intake temperature.
You also want to avoid excessive fuel rates which might prevent you from getting the range you need for the mission.
There has been much discussion and speculation about the top speed capability. My opinion as to why we don't yet know the official
top speed is because no one inside the program knows. Pilots flew the plane according to strict procedures controlled by the
training or mission parameters which dictated fuel rates and altitudes to obtain maximum range between re-fueling assets and turn
rates to prevent border or threat area incursions. The few times pilots got to push performance were in official speed record tests where clearly the plane was not being flown to its limits. Other high speed incidents occurred during missions where unexpected things happened. In some cases damage or loss resulted. In terms
of raw specifications, the airframe clearly surpassed the design specification of Mach 3.33 or 500 KIAS. In reality, the limitation
was not the power of the engine, but the danger of thermal damage beyond the intake temperature of 427C. The plane was never purposely flown above this limit. The limits set in this model provide a generous margin when operated in typical real-world flight profiles and weather.
- As close to 400 KIAS/360 KEAS as possible. Above 80K ft, lower airspeed is normal.
- Above 310 KEAS
- CIT below 427C
- EGT below 830C
- Fuel rates close to 18K lbs/engine (180 on digital readout)
- Pitch below + 6
- Pitch trim between 0 and -3
This is the most stable and low-maintenance stage of
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 indications.
You will monitor the intake spike for proper movement
CIT for temperature, CIP for needle aligment, and foward bypass for drag and unstart protection. If fuel loading procedures were followed carefully, the fuel balance and attrition system will maintain controlled flight and balance within operational limits without intervention. The auto system will most closely track ideal when fueled to the medium range profile of 66K lbs on the ground.
Panel warnings will activate if COG or speed is out of limits for the flight profile. You can correct small imbalances with the fuel pump switch in the fuel panel.
Above Mach 3, a green annunciator panel indication will light showing the ideal COG range for the current weight and AFt Bypass setting. Ideal pitch trim for best fuel efficiency will be between zero and minus 3. Positive trim is
normal early in the cruise at high fuel loads. Speeds of Mach 3.18+ where spike is fully retracked is best efficiency.
Keep this in mind:
- Higher, colder air provides higher mach indications and more fuel efficiency at a cost of reduced total engine power. Stalls are more likely.
- Lower, warmer air uses more fuel and heats the engine and surfaces. Over-speeds are more likely.
Note: High mach speeds procedures use KEAS
(available in the main panel "Triple" gauge.) rather than IAS.
Descents are the most challenging part of flying the SR-71. A lot goes on in a short time and the performance constraints are tight. The pilot needs to be alert and have all the activities planed out ahead of time.
Note: The angle at which the air enters the engine at supersonic speeds is critical. Notice the engines are pitched down compared to the airframe so while the airframe is pitched up slightly at cruise, the engines remain close to on-axis to the air flow. When descending supersonic, there is a limit to how much off axis the air flow can get without stalling the engines.
The object is to approach the descent point as close to 400 KIAS and 350 EAS or more as possible to make holding 365 KEAS in the descent as easy as possible. 365 KEAS is used because it keeps the plane well above 350 EAS below which unstarts are likely.
If you start the descent under 350 KIAS, you risk an unstart, so you must accellerate while at a shallow descent (no more then -1500 ft/min) until the plane is fast snough to engage EAS Hold safely.
If possible, try to obtain and lock in 365 KEAS hold just before or shortly after starting descent.
The easiest way to do this is when starting the decent and EAS is between 350 and 360, swith to IAS hold (if not already) and set your descent altitude target bug to a very low value (10 - 20K ft) and -4500 ft/min descent rate. This will give you time while the aircraft slowly accelerates to 365 EAS in the Triple gauge.
As the EAS display in the Triple gauge crosses 365 with a solid display, immediately click the KEAS Hold button on the refuel panel above the Drag Chute Lever or within Autopilot panel. The EASH display in the Autopilot panel will indicate the speed you have captured. Don't worry if your captured speed is a knot or two off.
Note: The EAS hold will not hold perfectly, but close enough to take the workload of managing the descent speed off the pilot. Most importantly, set properly, will prevent the EAS from going below critical 350. The new EASH display in the AP panel will indicate the current hold speed you have captured.
Soon after starting descent, close to the time of 365 EAS hold, the throttle will back off enough to force the afterburners to disengage. The hold will now transition to holding the documented *IAS* for the remainder of the descent. This helps insure the engine RPM will not fall below critical speed.
The engine spikes will start to extend. Power is now limited to full military, so you need to manage descent rates to stay near mile/altitude targets and keep the plane from flying too slow.
KEAS HOLD WILL NOT WORK IN MACH MODE.
You can now concentrate on managing the descent rate with two objectives:
1) Crossing various altitude targets at set distances from the landing or refueling target.
2) Preventing the engine RPM from spooling below 6100.
Note: Static temperatures colder than -74C will cause more difficulty keeping the RPM over 6100, so make sure the Aft Bypass Doors are set to CLOSED which adds some drag from the engines. When close to mimimum RPM, the EAS Hold will increase speed to try to keep the RPMs from dropping too low. In VERY cold descent temperatures, you may need to use the forward bypass knobs set to full open to add additional drag. You can also reduce the descent rate. Don't forget to close the aft bypass again below Mach 1.5.
Use the "friendly" descent target chart below and adjust descent rate (typically settings start around -4000 to -6000 near the end.)
When the aircraft speed is below Mach 1.5 you can relax a bit as unstarts from descent rates are no longer possible which means you cen set any speed and descent rate you want.
Mach 0.90 and 5500-6100 RPM is the standard cruise speed below Mach 1.
Descent angle is typically between 1 degree at the start to near -7 degrees around Mach 1. AOA gauge should never go below zero degrees.
If decent rates exceed -6200 ft/min, "CAB/N PSI will display on the Annunciator indicating the cabin pressure and fuel tank Nitrogen pressures are affected.
Reduce descent rate or switch pressure to 10K ft temporarily. 10K cabin pressure will increase H2O usage considerably.
Higher descent rates risk engine RPM falling below 6100 causing compressor stall.
KEAS hold has both minimum and maximum hold values built into it to restrict overspeeds and stalls. The Master Warning light and RPM digital readout changing from white, to yelllow, to red indicates the pilot must take action to avoid minimum RPM stall.
The chart graphic above is converted into more FS friendly table and is also displayed in the simulator kneeboard:
* Suggested descent rate may vary greatly based on altitude, speed, weight and weather.
Mach 2.5 and below 6900 RPM by this altitude.
M1.5/365 EAS/408 IAS
Opt: Disable EAS Hold. Set 388 IAS, maintain
400-410 IAS for landing target until restriction speed.
Under 150 miles:
If Hold still engaged, AP will continue to
slow to 379 IAS by 25K ft.
Set desc rate per desc calc gauge with approach target altitude set in AP alt.
Mote: Descentometer supplied with panel is most useful below 20K ft.
(Edited for sr2012Updt1c):
Slowing below Mach 0.90 "CG HI" in yellow could display on the Annunciator. This is an awarness status and normally does not require action. Fuel Low indicates tanks 2 or 4 are below minimums which is unlikely to occur in a normal flight with proper ground fuel loading.
At 18K ft, set IAS bug to 340, and 16K ft, set 320 KIAS. At 14k ft AGL, set 280 KIAS. At 12K ft AGL, slow to 250 KIAS by setting IAS bug to initially to 240 then adjust upward to hold 250. Within 30 miles of landing slow to 220 KIAS minimum turn speed (10K lbs fuel.)
Faster if heavier than 10K lbs total fuel.
o Terminal maneuvers and
light weight and slow, the model turns and changes speed rapidly.
The pilot manual describes the sub-sonic handling as "adequate"
and interviews with crew describe it this way in "SR-71 In Action":
"Subsonic, it feels like a big, heavy airplane,
and you have to horse the stick around a bit to get the airplane
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 @16 miles (manual control) to 20 miles (AP/APP mode) and 220 KIAS.
Higher fuel loads and or turbulence require higher speed.
When lined up reduce speed to 175 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. Threshold AOA is 9.5 degrees. Pitch is 10 degrees (not to exceed 14.)
Use shift-enter(FS9) Cntrol-Q(FSX) key sequence to lower the view to see the runway. In this model, the 3D panel provides the best undistorted view
shift-backspace(FS9) Control-shift-Q(FSX) to pitch up or SPACE key(FS9) to recenter view to default.
Note: Many pilots remap the FSX shift-num-0 back to FS9's spacebar.
The Approach Auto-pilot will hold a steady glideslope with fuel weights up to 22,000 lbs down to around 600 feet.
Observe the AOA gauge to keep the threshold attitude under around 9.5 degrees.
Note: Fuel weight over 40K lbs requires 275 knots IAS above 10K ft. keeping RPM over 6400 and land around 250 knots IAS and 10.5 degrees pitch.
- 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 lever center changing from black to orange. If there is significant crosswind, operate the chute manually after the front wheels touch down using shift-/.
- Between 500ft and 600ft take manual control (z key) of pitch, roll, and yaw while targeting 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 altitude after the key sequence control-r (to disengage AT control.)
On touchdown, chute will deploy on wheel contact WITH THROTTLE IDLE and AUTO-DEPLOY ENABLED.
Use stick back pressure to lower the nose slowly until front gear contact at 100 knots. On cross wind landing, deploy the chute manually AFTER front wheel contact.
-Begin gradual breaking ~65 knots ground speed. Anti Skid will prevent full breaking until speed passes below 12 knots. Expect
siginificant breaking effectiveness with rain, ice and snow.
- Around 30 knots jettison drag chute (/) or increase engine speed slightly for a few moments. Increasing speed resets the auto-spoiler logic.
- Taxi to parking not exceeding 20 knots ground speed or 30 MPH.
Shut down engines using contrl-shift-F1, reducing throttle(s)
below zero (typcially -3.1) or fuel panel switches.
Note: The high RPM of the idle 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 as a trade off.
Real world tanker descent (assumes M3.2 80Kft):
Speed and settings are similar to landing descent.
-Start descent 328 miles from runway. Tanker is expected
100 miles this side of runway.
-Set descent alt (target) in AP
for 29K-35K ft in IAS hold mode.
-Gradually set initial dec rate to 4500.
-Crossing 365 EAS click EAS Hold and increase descent rate to -5000 ft/min and follow tanking descent chart.
- 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 runway 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 220-230 KIAS minimum maneuvering speed.
PROCEDURE SECTION COMPLETE
For those interested, a more complete explanation of the Fuel Balancing System:
When the standard loads of 45K, 55K, and 65K lbs fuel are used, the resulting CG should be between 20% and 22% while on the ground. By the end of taxi, CG around +-21% is normal.
There are two modes of CG control: Passive and Active.
The position, quantity, and tank selection by normal FS attrition contributes largely to CG during climb and early cruise. Passive mode is indicated by zeros in the TGT: display and by the xFeed Open lamp lit bright in the Fuel Annunciator. If the pilot clicks on the xFeed ON switch, the Auto CG system will be disabled and xFeed forced on all the time. Note: It is not a good idea to click this switch to On (forced on) unless necessary which is why it defaults to off.
There are two active modes: Tank Selection and Tank Pumping.
Active is used largely to maintain high speed cruise CG, descent and landing CG. When in Active Mode, the xFeed Open lamp in the Fuel annunciator will not be lit and there will be a non-zero number displayed in the Fuel Panel "TGT:".
When the CG error is low but a correction necessary, individual tanks are selected which affect the balance in the desired direction. If the error grows beyond a certain limit (which could happen if the tank switching does not affect the CG fast enough) tanks 2 and 4 (centers) will pump fore and aft until the error is within tank selection or passive system effectiveness. Active pumping is indicated by the green lamps lit bright in on the Fuel Panel Pump switch. If these two tanks are full or near empty, the active pump is suppressed, but the active switching continues. Below 8000 pouds total fuel, all active correction is suppressed and passive only is in effect. Active mode is indicated by a target CG number in the "TGT:" display and the Fuel Annunciator xFeed Open not lit (unless the pilot clicked to over-ride.) The TGT percent is the CG the Active mode is trying to enforce an upper or lower limit on.
For Active/Auto pumping to operate, the pump switch has to be in the Center position and the Pump Rel light in the Fuel Annunciator must not be illuminated. If Pump Rel is activated, the auto pump system is disabled and the pump must be operated manually.
During the climb, tanks 1 and 4 deplete together providing a slow CG transfer to rear. At heavy weights, the rear tank 6 engages to prevent excessive rear CG for the weight. As speed increases above mach 3.05 and below 120K lbs gross weight, the CG will gradually move rearward based on speed to the maximum of 24.97%. If the pilot attemps to intervene for CG greater than 25%, the tank 6 will again engage to attempt to prevent this. Active pumping will engage if active switching is ineffective.
When tank 1 is empty, tank 2 will take over maintaining rear CG until it reaches the minimum of ~5400 lbs. This is just enough weight to provide some pilot intervention when landing near or below 10,000 lbs fuel weight. Your flight plan should always allow for landing as close to 10,000 lbs fuel as possible.
Below 30,000 lbs total fuel weight, CG is gradually lowered in favor of setting up descent and landing. Below 30K lbs fuel the influence on balance error is much reduced and the Annunciator no longer displays the suggested CG hint. This is not a problem.
As the aircraft approaches the terminal area and 21.5% CG, the remaining tank levels will work together to hold this CG as long as possible. Active CG control may not work well or at all with fuel levels under 8,000 lbs. Keep in mind 21.5% is the ideal CG for a 10,000 lbs fuel landing, so low CG and under 10K lbs fuel is not a big problem. It's quite easy to perform a good landing below this weight when proper AOA and speeds are used. The closer to 10,000 lbs fuel, the less the pilot has to be concerned with fuel balance maintenance and the landing is the easiest. Heavier weight also makes stopping a little easier when at low speed, but harder whan at high speed.
Note: If the tanks are unbalanced left and right automated CG errors would occur. To prevent this, crossfeed is on for all tanks in passive mode, meaning there is no Left and Right engine isolation.
Passive mode is also engaged in an engine stall or unstart where the crossfeed will minimize L and R inbalance while only one engine is operating.
Some interesting facts:
The SR is composed of Titanium and Composite (plastic/carbon) 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 nose section can be removed and swapped with various configurations in radar and sensors and different shapes to the nose.
Speed/Altitude Limits: The highest speeds and altitudes claimed by verifyable sources are Mach 3.5 above which center window frame heats to the point of damaging the windows and a reported accidental altitude of 87,000 ft. The world record of 85,000 ft is considered the maximum safe altitude above which the engines start to become starved for oxygen. Conditions at which 85K ft and above can be obtained are not always available (ideal temperatures, pressure and weight.)
Costs to operate have been difficult to estimate due to the large variation in missions.
In my opinion, the most believable figure is $27,000 to $32,000 per hour exluding tankers, training, and various logistical support.
The A-12s were never called "blackbirds" and were referred to by their program name "CYGNUS" or "CYG".
The SR-71's fly at 33+ miles per minute (1,980 MPH/1,722+ knts) or 3,000 feet per second, faster than a 30-06 bullet.
Each SR-71 cost 33 million to build.
At Mach 3.0 the air flowing into the engine intake has to slow down to Mach .6 to prevent compressor stall. This is the equivalent of slowing from 2100 MPH to 600 MPH in 20 feet.
Aircraft skin temperature can reach 800+ deg F.
Refueling was not performed primarily because of high fuel loss from leakage, but to have a larger performance margin on take off in case of an engine flameout. At full fuel load above 35 ft, the
minimum dyamic control speed with one engine on full military
power is over 280 knots indicated!
On average, an unstart would occur about 1 out of 5 flights. Some planes more often than others.
Sonic Boom transmission time 75K ft: 1 min, 20 sec.
AB in Flight:
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. These shots were taken after closing the SR-71 program while burning off the last
of the stored fuel.
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
Ben Rich of Lockheed announced that the SR-71 had over 1,000
missile launches against it, but none successful. In 1981 a confirmed missle launch of
two SA-2 missiles on an SR-71 occured near the Korean DMZ. The typical evasion technique was to keep flying straight so as not to slow down. Then existing communist computer technology was not fast enough to calculate an intercept from 16 miles away at closest point.
Pilots in a pressure suit can lose up to 5 pounds in a four
Because of the sleek "hooded" appearance
of the Blackbird caused by the chine, the Okinawans claimed it
looked like a Habu cobra snake. Thus the nickname.
Apparently it's not normally aggressive to humans but has a
SR-71 Crew members are also called "Habus."
RODN is famous for the "Habu Hill" where friends, familly and local
fanatics would gather to watch and photograph a take off. Pilots would rate each other on how large a crowd they could attract.
The SR-71 flew for 17 straight years (1972-1989) by the US Air Force without a loss
of plane or crew. Of the 50 variants produced, 19 crashed with no
loss of US Air Force crew.
One CIA crew was lost launching a drone in an M-21.
The recon officer drowned in his chute on landing in water.
Another accident related to right engine unstart during turn at cruise
causing a breakup and loss of the RSO during a Lockheed test
The Seattle Museum of Flight in addition to the
drone-mounted M-21 has the nose of a
crashed SR71 on landing at Kadena when the front gear collapsed in a storm.
The rest of the plane burned, RSO ejected and pilot rode it out until it
Visitors can sit in this cockpit.
Last Flight documented by NASA Dryden Edwards AFB web site:
"NASA's SR-71A served as a research platform from 1992 until its final flight flown by Smith and Meyer on Oct. 9, 1999, the last flight by any SR-71. It remains on display at NASA Dryden today. NASA's SR-71B served as both a research platform and for crew training and pilot proficiency until its final flight in October 1997."
478 total people have flown the Blackbirds. More people have
climbed to the top of Mount Everest in that time.
- The first test flight of A-12 was made on 26 April 1962 by Lockheed Test Pilot Lou Schalk from Area 51.
- 29 October 1964: SR-71 prototype (#61-7950) delivered to Palmdale.
- 22 December 1964: First flight of the SR-71 with Lockheed test pilot Bob Gilliland at AF Plant #42.
- 5 February 1968: Lockheed ordered to destroy A-12, YF-12, and SR-71 tooling.
- 21 March 1968: First SR-71 (#61-7976) operational mission flown from Kadena Airbase over Vietnam.
- Sept 1, 1974: Beale to Farnborough World record flight.
- Sept 13, 1974: Mildenhall to Beale World record flight.
- 15 January 1982: SR-71B #61-7956 flies its 1,000th sortie.
- 22 November 1989: Air Force SR-71 program officially terminated.
- 21 January 1990: Last SR-71 (#61-7962) left Kadena AB.
- March 6, 1990: Last official Flight Palmdale to Dulles setting new world records delivering to Smithsonian Museum.
- Last flight of a military SR71 into Beale AFB for display: 1997
- NASA used one of its two SR aircraft for research on the LASRE aerospike engine
project as late as 1998:
Program Info:(as of Jan 1990) Source:
* Total Flight Hours:...........53,490
* Total Mach 3+
* 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
* 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/repair/training sites:
EGUN Mildenhall England (Det 1.)
EGUL Lakenheath England
(temporary during Mildenhall runway repairs.)
RODN Kadena Okinawa Japan (Det 4.)
KBAB Beale Air Force Base Marysville
California USA (9th Reconnaisance Wing US Air Force.)
KHIF Hill AFB Utah.
KEDW Edwards Air Force Base California USA (Dryden.)
KPMD Palmdale (Lockheed Martin Skunkworks Palmdale, CA)
Note: Most flights out of Palmdale
were operated by CIA or Lockheed test pilots
and had differing procedures from the USAF including no air refueling.
KSKA Fairchild AFB Spokane WA USA (training.)
KOFF Offutt AFB Nebraska USA:
One brief landing was during the Sunday Mt. St. Helens eruption.
VTUD Udon Tailand.
KGSB Seymour Johnson AFB North Carolina (1973 Israeli War)
KNFL Fallon AFB Nevada (one emergency landing)
KRDR Grand Forks AFB North Dakota (one emergency night landing Gen/Hyd/ADS failure flying E over Canada)
FJDG Diego Garcia Navy Base (one landing)
Carswell AFB, Texas (KNFW Frt Worth NAS?): One landing.
Hydraulic pump failure with ground refueling from a parked tanker aircraft.
AR51 Area 51 Groom Lake "The Farm"