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Lockheed YF-12A

FAI absolute closed-course speed of 2,070.101 mph on 1 May 1965, the figure in NASA's YF-12 monograph. A museum page prints 2,062 mph for the same flight.

Also known as YF-12, YF-12A
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Top speed

Published as 2,070.101 mphPublished as 2,070.101 mphPublished as 2,070.101 mphPublished as 2,070.101 mph

FAI 15/25 km closed-circuit absolute speed, YF-12A 60-6936, Edwards. NASA's 2,070.101 mph is the rank. The Air Force museum prints 2,062 mph.

OfficialNASA (opens source in a new tab)

In context

  • London to New York in 1 h 40 minConstant · London to New York, 5,570 km great-circle
  • 32× a cheetah's timed top speedSourced · Cheetah, 29 m/s. Sharp 1997, mean of three timed runs over 201.2 m
  • 10 football fields a secondConstant · American football field, 100 yd (91.44 m)

Worked out from the sourced figure above, which stays the ranked number.

This list

Why it's so fast

An air-breathing plane is fast when its engines still make thrust in air that is ramming the inlets, and when the airframe can stand the heat. A rocket plane is a different machine.

  1. The inlet is the hard part

    A jet engine wants subsonic air at the compressor. At high speed the inlet has to slow that air down with shocks, or the engine stops making sense.

  2. Heat and structure

    Skin friction heats the airframe. The speed record is as much about surviving that heat as it is about the engine.

The air-breathing record holder is the SR-71 Blackbird.

This is how the category works. A note written for this entry appears here once it is in the database.

Provenance

Every measurement

Claimed, measured and official figures side by side, each with its source. The ranked figure is marked.

  1. 3,332km/h2,070.101mph925m/s1,799knMach2.72Ranked figure

    FAI 15/25 km closed-circuit absolute speed, YF-12A 60-6936, Edwards. NASA's 2,070.101 mph is the rank. The Air Force museum prints 2,062 mph.

    White Eagle prints 2,070.102 mph. The U.S. Air Force museum Thompson Trophy page prints 2,062 mph. Those are noted, not stored.

    Official
    NASA (opens source in a new tab)

Reference

Specs

Crew
Robert L. Stephens and Daniel Andre
Aircraft
YF-12A 60-6936
Course
15/25 km closed circuit
Date
1 May 1965

Context

Background

NASA's YF-12 flight monograph prints a closed-course speed of 2,070.101 mph on 1 May 1965, with a sustained altitude of 80,257.65 feet on the same day. That is the ranked figure. White Eagle Aerospace's account of the same Edwards flights prints 2,070.102 mph for the 15/25 km closed-circuit absolute, YF-12A 60-6936, crew Col Robert L. Stephens and Lt Col Daniel Andre. The extra thousandth is rounding, so it is the same record.

The National Museum of the U.S. Air Force's Thompson Trophy page prints 2,062 mph on 1 May 1965. That is a real disagreement of about eight miles per hour, not a unit conversion. The monograph is the NASA research account of the official records, so 2,070.101 mph is the rank and 2,062 mph stays in the method note. A different crew's 1,000 km course that day is not this row.

Head to head

Compare Lockheed YF-12A

Open the speed race

Spot a wrong number?

Every report is read by a person, and corrections are dated on the page.