Cover Designations for Classified USAF Aircraft
Copyright © 2004 Andreas Parsch
In the late 1960s the
U.S. Air Force began to acquire Soviet fighter aircraft for the purpose of
evaluation and air-to-air combat training. The acquistion
and use of these aircraft was then highly secret, and operations were flown
from the test facility at
Just like any other USAF
pilots, the men flying the secret aircraft had to log their flight hours in
standard USAF forms. These forms required the entry of the aircraft type flown,
but of course you couldn't simply write "MiG-21" into that line! At
some time early in the program, someone had the idea to use "fake"
cover designations, which looked like ordinary Air Force designations,
but which were not used by any actual aircraft. It was decided to continue the
old F-for-Fighter series of the USAF, which had reached F-111, but had been
discontinued in 1962 when the DOD introduced a new joint designation system.
Therefore, the numbers used were 110 (the original F-110A designation had been
replaced by F-4C, so that 110 was de facto unused), 112, 113, etc. All
designations were prefixed by a "Y", indicating a test model. Over
the years, the system of assigning YF-1xx designations was extended to
U.S.-built secret aircraft as well.
Note: Although none of the above is
officially acknowledged by the USAF, it isn't explicitly denied either, and
there is enough evidence available to ascertain that the information given
above is essentially correct. For example, the author's FOIA request to the
AFFTC (Air Force Flight Test Center) at Edwards AFB for "YF-xxx"
designations for revealed projects (e.g. HAVE BLUE, TACIT BLUE, "Bird of
Prey") did not return with a "No records found" response.
Instead, records were forwarded by AFFTC's 412th TFW
to the Pentagon office SAF/AAZ (Secretary of the Air Force, Directory of
Security and Special Programs Oversight). Although the records were denied in
full, their existence was not denied.
Apart from fake
designations, fake USAF serial numbers were used as well. The latter are
reported to include 75-001, 75-004, 75-008 and 75-010, which are all officially
listed as "cancelled serials".
Because the USAF so far
doesn't officially acknowledge the use of said cover designations, all
numbers presented here are technically rumours only.
However, several numbers have been forwarded by reliable sources so that there
can be no doubt that at least some secret aircraft did indeed receive such
designations.
The "References"
column indicates the sources of the alleged designations:
[1] Curtiss
Peebles: "Dark Eagles"
[2] Official USAF biographies, an example being the biography of John T. Manclark.
The references to YF-110 and YF-113 in the list of aircraft flown are gone, but
were originally included. The original version of the file can still be seen on
the FAS
site.
[3] Aviation Week & Space Technology. In 2000 and 2001, there were a few
short notes in AW&ST about the alleged YF-113G aircraft. These notes
included some information on the use of YF-1xx designations.
[4] Peter Merlin. Peter is an aviation historian with some detail knowledge
about operations at
[5] Tom Smith. Tom (not his real name) is a person, who has provided some
information as well as the background story how he acquired his data (this
story explains why he doesn't know the actual aircraft type associated with
each designation). He asked not to reveal his name or background.
[6] Joseph Jones. Author and (self-proclaimed)
"insider" on secret aircraft projects.
A blank
"Remarks" column means that the respective designation has been
quoted by the source(s), but no details whatsoever have been provided.
|
Designation |
References |
Remarks |
|
YF-110 |
[1,2] |
YF-110
is associated by [1] with the MiG-21. However, no specific subtype is
mentioned, and it is possible that all actual YF-110 designators had a suffix
letter |
|
YF-110B |
[4,5] |
[5] quotes the serials 75-001, 75-004 and 75-010 for this
type. |
|
YF-110C |
[5] |
|
|
YF-112 |
[3,4] |
This is
mentioned as "used for a MiG". It is
likely that this remark only refers to the general use of "YF-112"
for ex-Soviet aircraft, and not a specific type. Therefore a
"plain" YF-112 designation (without suffix) may be non-existent. |
|
YF-112C |
[5] |
|
|
YF-113 |
[1,2,5] |
[1] associates the general YF-113 designation with the MiG-23.
[5] explicitly claims the use of a plain (no suffix)
YF-113 designation. |
|
YF-113B |
[3,4] |
This is
said to be an aircraft of the MiG-23/27 "Flogger" family. |
|
YF-113E |
[3] |
This is
said to be another variant of the MiG-23. |
|
YF-113G |
[3,4,6] |
There
was much speculation about this designation, and there have actually been
three different ideas about the identity of the YF-113G: |
|
YF-114C |
[4,5] |
[4] says this is an unidentified MiG
type. |
|
YF-114D |
[5] |
The
serial 75-008 is quoted as used by a YF-114D. |
|
YF-117A |
(multiple) |
Although
never explicitly said, it is assumed that the Lockheed SENIOR TREND aircraft
had received the YF-117A cover designation. This designation was eventually
allocated as the official designation when the aircraft was revealed to the
public, thus creating the only official post-111 F-designator. |
|
YF-117E |
[4,6] |
Reported
to be unrelated to the F-117A |
|
F-121 |
[6] |
This is
claimed to be the designation for a pure-delta stealthy high-speed
reconnaissance aircraft developed by General Dynamics (now Lockheed Martin).
For details about this aircraft, see this
page (based on info from [6]). However, it must be noted that the story
of this aircraft and its F-121 designator is questionable at best. |
|
YF-1xx |
[4] |
Northrop
TACIT BLUE. This aircraft had a YF-1xx
designation, but not in the -113() series. |
|
YF-1xx |
[4] |
Boeing Bird
of Prey. This aircraft had a YF-1xx
designation, but not -113G. |
There are also reports
which link the F-116 and F-118 designations to the MiG-25 and MiG-29,
respectively. But these reports are rather vague rumours
which do not claim any "first hand source" as a reference, and are
therefore not included in the above listing.
Even if no official and
only very limited unofficial information is available on the system of cover
designations, one can draw a few conclusions:
- The designations are
not allocated in the same way as "normal" designations. I.e., the
USAF office responsible for the assignment and maintenance of official aircraft
designations is not involved.
- Most likely the
designations are not allocated on the basis of one number per basic aircraft
type and one suffix letter per version. As can be seen from the examples in the
preceding section, the numbers 113 and 117 with different suffixes were
apparently used by several types. Additionally, the numbers and suffix letters
are not assigned in numerical and alphabetical sequence. It obviously makes
sense to hide the actual number of different designations this way.
- The "F" or
"YF" prefix doesn't mean "Fighter" as in normal
designations (at least not anymore). Evidence for this is the TACIT BLUE, which
had a YF designation, but wasn't designed in any way
to be a fighter. It makes sense to hide the mission or type of a secret project
by simply assigning the same designation prefix to all aircraft.
- It's possible that the
Lockheed HAVE BLUE never received a YF-1xx
style designation.
Comments and corrections to: Andreas Parsch
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Last
Updated: 11 December 2004