Fly 972's record speed run from Palmdale AF Plant 42 (KPMD) to Washington Dulles Intl (KIAD).
Your abilities to get maximum speed out of the SR-71 will be challenged as you set your own speed records on this flight.
After take-off and with 480 KIAS hold engaged,set Sandel to show GPS info in lower right of the gauge. Click SHFT on lower left, then cycle BRG until GPS information shows up on lower right corner of gauge.
Prompts to change speed will be given at 3.0, 1.5, 1.0, and 0.5 nm from the refueller. If you are going too fast, you will be closer than the prompt states and you should slow down more than stated until prompts come just before the distance stated.
Afterburners should remain on (throttles >80.0%) throughout the refuelling process. Quick speed bug settings below 305 knots may cause the AB to go out and re-ignite later. Avoid this because it costs one TEB unit on each engine each time the AB re-ignite and you don't want to use up all the TEBs.>
NEAR APPROACH ,0.3 NM: Airspeed should be 310 to 311 knots as you appoach the tanker, set speed bug to 307 to 308 knots when nearing the drogue. Going a little faster than the tanker is ok because aircraft will slow when it begins taking on fuel.
CONTACT: Be ready to increase up elevator and elevator trim as fuel weight is added to your aircraft. Speed will decrease toward 305 knots. Increase speed bug 310 - 315 knots to keep in position beneath tanker with yellow stripe on his belly centered above you. If you break contact, adjust speed and position to re-establish contact and fuel flow.
TANKS FULL: Drop down a little and slowly bank left until you get "switching frequency" message. Then re-engage NAV hold and increase speed bug to 360 knots.
TANKER RACETRACK PATTERN: If you have trouble refuelling, the tanker flies a racetrack pattern along this leg of the flight plan so you can continue to refuel until tanks are full.
For versions 4K and later you can't set Aft Bypass Doors back to position A until Forward Bypass Doors close (<2%) above Mach 2.8 or so. Set Aft Bypass Doors to CLOSED when above Mach 3.2
WAYPOINT 6: Use manual heading control to get on course 066 as you pass Waypoint 6. This will help you get crosstrack error to less than 0.1 nm before you reach West Gate waypoint. Set Mach hold above 3.10 to get a special message at West Gate.
Increasing ground speed while keeping the instruments in normal range is your goal after the starting gates.
Increase Mach bug setting hundredths digit by one or two above current speed. Keep course deviations small, look for good tailwinds and colder air at different altitudes
You must adjust altitude and airspeed to prevent engine failure and structural damage while seeking higher ground speeds
Change altitude in small increments (200 - 500 feet) at no more than 400 feet per minute. Watch Static C temperature and wind speed/direction for favorable changes.
The most important indicators are the Exhaust Gas Temperature (EGT), Compressor Inlet Temperature (CIT) and Pressure (CIP/PSIA), Air Speed Indicator (ASI) and Fuel Flow (FFI.)
To prevent structural damage or stalls, the aircraft has to be flown within a 140 knot speed band (370 - 510 KIAS.)
Version 4K and later has tendancy to unstart on Engine2 without warning above Mach 3.27 and 1900 knots ground speed if CIP goes above 16.2. However, the unstart doesn't seem to happen after Kansas City gate. If you have an unstart start a -1500 fpm dive and decrease speed setting.
CIT and CIP
When the CIP needles are lined up, you're flying the optimum speed for current altitude, climb, cruise, and descent
The Forward Bypass Door position gauge is your friend. Indications higher than 7% open (above the green) represents increasing drag. Keep the bypass position below 7% at cruise. You will have high drag indications during climb and descent which is normal. Speed and Aft Bypass Door settings are used to control Forward Bypass. More open Aft doors will close Forward doors. More open Forward doors will lower CIP.
EGT, STATIC C, and ISA
Keep EGTs in trim range 801-805 C (below 830C for version 4a1) and CIT below 425C. Overly aggressive speed and climb rate settings will push EGT out of trim range. Fuel flow rates above 20K lbs/hr per engine can indicate you are pushing engine too hard. 18K lbs/hr per engine is normal cruise fuel flow rate.
Colder air will lower CIT and allow higher speeds, but you may have to lower speed setting before finding colder air
The ISA temperature guide on the main panel lower right will help you judge performance. If the Static C is colder than ISA, the plane will fly faster and higher. When warmer, the plane's altitude and speed will be lower than specification due to engine heating.
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.
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 accelerate while at a shallow descent (no more then -1500 ft/min) until the plane is fast snough to engage EAS Hold safely.
Close Aft Bypass doors and switch to IAS hold at 400 knots (KEAS hold does not work in Mach hold mode)
Set target altitude and descent rate to -4500 ft/min. Engage KEAS hold when EAS crosses above 365. Follow descent chart in the Checklist