DOCUMENTATIONSpecifications and Limitations
The numbers our U-2S works with: size, weights, engine, speeds and limits. Where a limit has an alert, the alert is named. Where the sim enforces nothing, this page says so.
Sim values. Performance values are measured in the sim. They may not accurately represent (nor do they intend to accurately represent) the performance of the real aircraft.
103 ftWingspan
40,000 lbMaximum gross weight
17,000 lbThrust, sea level, full throttle
2,917 galFuel, full tanks
Dimensions
| Item | Value |
|---|---|
| Wingspan | 103 ft |
| Wing area | 1,000 sq ft |
| Length, nose to tail | about 64 ft |
| Height, on the main wheel, level | about 17 ft |
| Main wheel to tailwheel | 21.7 ft |
| Pogo wheels, left to right | 59 ft |
| Wingtip skids, from the centerline | 51 ft each side |
| Ground attitude on main wheel and tailwheel | 3.6° nose up |
Weights
| Item | Value |
|---|---|
| Empty weight | 16,230 lb |
| Pilot with pressure suit | 210 lb |
| Nose, superpods, Q-bay, SPAN, external sensors | see EFB Aircraft tab |
| Fuel, full tanks | 2,917 US gal (about 19,540 lb at 6.7 lb/gal) |
| Maximum gross weight | 40,000 lb |
| Center of gravity range | 17 - 28 % MAC |
| Landing weight for the normal technique | 24,300 lb or less |
The aircraft does not stop you loading more than 40,000 lb. The EFB Aircraft tab shows Gross against 40,000 lb and warns you above it. Some typical loads:
Payload includes the pilot and, where fitted, the 1,050 lb OBC in the Q-bay. Each external sensor adds 300 lb (all four are fitted by default); Senior Spear adds 400 lb.
Engine
| Item | Value |
|---|---|
| Engine | GE F118 |
| Rated thrust, sea level, static | about 17,000 lb at full throttle |
| Ground idle, sea level | about 60 % N2 / 22 % N1 |
| Idle thrust, low down | about 370 lb, held by the engine control up to about 160 KIAS |
| Flight idle, above about 18,000 ft | about 80 - 85 % N2 / 65 - 75 % N1 |
| Light-off on a ground start | 18 % N2 or more (throttle to IDLE at 20 %) |
| Starter cut-out | 50 % N2 |
| Thrust in SEC, full throttle | up to 10 % less than in PRI (no throttle stop) |
| Airstart (emergency start system) | 25,000 ft or lower, 90 KIAS or more (any speed below 10,000 ft), one attempt |
The limits below are shown on SYS → PERF in red or yellow, and raise an MFD alert. See System Pages and Warnings and Alerts.
| Parameter | Normal | Limit and alert |
|---|---|---|
| N1 | about 22 % at ground idle, 92 - 96 % at full throttle | Readout red above 100 %. N1 FAN OVERSPEED above 102 %. |
| N2 | about 60 % at ground idle, 96 - 101 % at full throttle | Readout red above 106.3 %. N2 CORE OVERSPEED above 106.3 %, or above 105.8 % for 10 seconds. |
| EGT | about 420 °C at ground idle, 760 °C at full throttle on takeoff (830 °C on a day 20 °C above standard), 650 - 725 °C at climb power | Running (N2 above 55 %): red and EGT HIGH from 842 °C. In a start: above 890 °C, or 843 °C for 10 seconds. |
| Oil pressure | about 22 psi at idle, 50 psi at full power | OIL and ENG OIL PRESS LOW at 10 psi or less (not on the ground below 55 % N2). ENG OIL PRESS HIGH at 75 psi for 10 seconds. |
| Oil temperature | - | ENG OIL TEMP HIGH at 160 °C, LOW at -40 °C. |
| Oil quantity | 12 qt when full, in level flight. The reading changes in a climb or a descent. | ENG OIL QTY LOW below 8 qt. Read it in level flight. |
| Hydraulic pressure | about 3,000 psi | HYD below 2,500 psi. HYD PRESS LOW below 2,850 psi on the ground (above 55 % N2) or 2,800 psi in the air, for 5 seconds. HYD PRESS HIGH above 3,250 psi for 5 seconds, or above 3,500. |
| Fuel pressure | 15 - 19 psi, two pumps | FUEL PRESS LOW below 8 psi, FUEL PRESS HIGH above 25. |
| Sump quantity | about 70 gal (50 on the outboards) | FUEL SUMP and FUEL SUMP LOW at about 38 gal. |
In PRI the engine control holds the EGT at 840 °C, just under EGT HIGH; in SEC nothing holds it, and full throttle above about 55,000 ft runs past 842 °C. Hold 650 - 725 °C with the vernier up there.
The MEC cuts the fuel if N2 reaches 110.25 %; bring the throttle below 10 % to clear it. Past a limit you get the alert; the engine is not damaged.
Speed Limits
The U-2's speed limit changes with altitude and with the gust-control setting. The PFD and SFD draw it as a red band, and the speed digits turn red when you pass it. The lower of the airspeed and Mach limits applies.
| Altitude | Airspeed limit | Mach limit |
|---|---|---|
| Below 30,500 ft | 181 KIAS wing faired 241 KIAS gust control UP |
M .751 |
| 30,500 - 42,999 ft | M .651 | |
| 43,000 - 49,499 ft | 181 KIAS either way | M .751 |
| 49,500 ft and above | none |
| Alert | Comes on |
|---|---|
| AIRSPEED and AIRSPEED HIGH | From 180 KIAS wing faired, 230 KIAS gust control UP - at any altitude. |
| AIRCRAFT OVERSPEED | At or past the red band, airspeed or Mach. |
| MACH RATE | When, at your present rate of acceleration, you will reach M .75 within 5 seconds. |
| AIRSPEED DEVIATION / MACH DEVIATION | Only if you set the PFD speed limit monitors (L1 A/S). |
Performance Calculator
Stall speeds, takeoff and landing speeds and distances, the cruise ceiling and the fuel for a trip, for your fit and your conditions. It is the calculator of the Datalink portal, on the same aircraft numbers (flight model, engine tables and the EFB fuel model). Your entries are kept in this browser.
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Cruise Techniques
The Technique selector on the CONFIG tab sets how the cruise is flown. The fuel, range and cruise altitude figures change with it.
| Technique | How it is flown | Result |
|---|---|---|
| Long-range cruise | Full throttle climb, then Mach 0.715 at 3,000 ft below the altitude where the climb rate falls to 100 ft/min. The speed stays at least 10 kt above the stall, and the altitude stays at 80,000 ft or lower. As the fuel burns, the aircraft climbs slowly. | The throttle is below full in the cruise. This gives the lowest fuel burn for each NM and the longest range. |
| Max-altitude cruise | Full throttle all the time. The aircraft climbs until the climb rate falls to 50 ft/min, then holds the altitude. This is the method of the EFB fuel planner. | A higher cruise altitude, with 25 - 35 % more fuel for each NM than the long-range cruise. |
Use the max-altitude cruise to get the same figures as the EFB in the aircraft. Use the long-range cruise to plan for the maximum distance. For the technique in flight, see High Altitude and the Cruise Climb.
| Altitude limit | Value |
|---|---|
| Altitude the autopilot can hold | up to 75,000 ft |
| Flaps | none above 45,000 ft |
| Airstart | 25,000 ft or lower |
| Cabin pressure differential | 3.88 psi (canopy seal ON) |
Load Factor
| Flaps | Positive | Negative |
|---|---|---|
| Up | +4.0 g | -3.2 g |
| Down | +2.8 g | -2.4 g |
Structural limits of the flight model. MSFS applies them only with its aircraft stress damage option on. There is no g warning: watch the PFD G meter. Less than 0.2 g for more than about 1.5 seconds gives AMAD and AMAD OIL PRESS LOW.