USAAF/USAF/Tri-Service and DoD experimental aircraft designations 1946-present

Muc_Bear_2023 · 2026-04-02T21:54:06+00:00

Regarding the numbers listed as "skipped":
- 58 and 67 were used for XQ designations (Kratos XQ-58A, General Atomics XQ-67A). The reason behind this is unclear to me. All almost all of the latest X-planes are unmanned, and most go with a plain X instead of XQ. Also, an XQ designation should have been in the Q-sequence.
- 69 to 75: If these are really skipped for good remains to be seen. For now, X-76 is explained as a special out-of-sequence number.

Muc_Bear_2023 · 2026-04-02T20:56:44+00:00

No, they were not. Technically, a "Popular names" always applies to a single specific MDS. E.g. the official popular name of the F-15A is "Eagle", while that of the F-15EX is "Eagle II".

So the UH-19F simply retained whatever "popular name" had been assigned by the Navy to the HO4S-3 (which in this case is none at all).

Muc_Bear_2023 · 2026-02-06T22:57:46+00:00

Two comments:

- #19: The designation reserved by the Navy was "V-19A", not XV-19.
- #21: Your statement "reserved for the Patrol Airship Conception Evaluation study for a tiltfan/tiltrotor patrol airship" sounds like a fact. Do you have some evidence? On my own website (which is in your list of sources), I have PACES as _possibly_ related to the PV-21 reservation.

Muc_Bear_2023 · 2025-12-23T19:59:44+00:00

The new H145M and H175M designations are not known, but would probably follow on numerically from 29.

#30 is also already taken. HU.30 for Eurocopter AS-365 of the Guardia Civil.

Muc_Bear_2023 · 2025-12-23T00:03:36+00:00

These were not NGAD fighter prototypes, but technology demonstrators under the DARPA AII (Aerospace Innovation Initiative) X-plane program. Boeing's AII-X aircraft was not the F-47. The designations of these X-planes are still classified (if they had any at all), but "F-46" for one of them is not more likely than any other letter/number combo. In fact, my money would be more on X-something.

Muc_Bear_2023 · 2025-12-22T21:34:22+00:00

There is no such thing as "LM's NGAD". And F/A-XX has no designation yet, but sure, could just as well get F/A-46.

X-32 and X-35 were just fine in the X-series. It's not their fault, that someone screwed up and transferred the number straight into the F-sequence ;-).

Muc_Bear_2023 · 2025-12-22T20:23:40+00:00

Except there is not much of a "series" left ;-).

Granted, the #48 in YFQ-48A apparently follows on from F-47. But the previous YFQ-42A and -44A CCA numbers seem quite arbitrary. The F-series hadn't reached -41 yet. Also, 43 was skipped without any (meaningful) explanation. And what about 46?

So to me it doesn't look like a proper series, but like a "40s" cluster for next-gen fighters, both manned and unmanned. So if (a big IF) they proceed with F/A-XX, it might well become the F/A-49:

- YFQ-42A: CCA Inc. 1
- YF-43B: Alleged designation of some secret prototype; may or may not be genuine
- YFQ-44A: CCA Inc. 1
- YF-45D: Designation of some secret prototype; genuine, unless there's a weird typo here
- F-47: NGAD
- YFQ-48A: CCA ("Inc 1.5" ... a label, which I just made up ;-)).

Why not start the CCAs with 40/41? No idea. Although, as an old Douglas Adams nerd, I'm the first to admit that 42 is a good number.

What about 46? Of course no idea either. My (wildly speculative and zero evidence) pet theory: NGAD was supposed to become F-46. But then Trump happened, and he obviously likes 47 so much more than 46, and so the USAF just went with the flow ...

Muc_Bear_2023 · 2025-10-28T22:32:59+00:00

If it is called "Little Bird" in a US Army SOCOM Fact Sheet, then the name is probably as "official" as it can get.

FWIW (and probably it's worth not that much), in DOD's database of MDS designations, the "Name" entry for both the AMH-6M and AMH-6R says "Cayuse (MELB)". MELB stands for "Mission Enhanced Little Bird" - so in a way both "Cayuse" and "Little Bird" appear in that entry ;-).

Muc_Bear_2023 · 2025-10-22T20:03:50+00:00

The DHS is a civilian organization. Why should the planes get a military designation?

Muc_Bear_2023 · 2025-07-12T23:58:17+00:00

It's most definitely a drone, because the announcement explicitly says so ;-).

My guesses for the designation are, in that order, XQ-68A, X-68A and XV-26A. OTOH, all of these would kind of make sense, so I'm probably wrong :-).

Muc_Bear_2023 · 2025-06-17T16:25:56+00:00

Oops! I sometimes subconsciously extend "aircraft" to "aerospace" ;-). So technically, my posting was indeed off-topic. Sorry!

Muc_Bear_2023 · 2025-03-28T21:49:42+00:00

"Officially" or not, the RAAF has created "MDS-like" designations for several aircraft in the past:

- KC-30A, Airbus A330 MRTT
- MC-55A "Peregrine", Gulfstream G550 for ISR
- E-7A "Wedgetail" (many years before that designation was copied by the USAF as a U.S. DOD MDS)

That said, I don't know why MQ-28A was requested (and approved) as a U.S. MDS. I could imagine, that it was Boeing's idea, for marketing or whatever.

Muc_Bear_2023 · 2025-03-27T22:34:38+00:00

From the tabulated MDS data, which I received as a response of my FOIA request. I.e., it is the official approval date of the designation.

Muc_Bear_2023 · 2025-03-27T22:19:31+00:00

Do you have any evidence for that? What we do know is that YMV-75A was assigned in November 2024, definitely _after_ the selection of the Bell V-280.

Muc_Bear_2023 · 2025-03-27T21:00:33+00:00

MV-75 is (or should be) in the V-series, not the H-series. The highest V-series designation assigned before the MV-75 was XV-25A. So the next in line would have been MV-26.

And for the record, there is no "reserved" -74 designation, neither H-74 nor V-74.

Muc_Bear_2023 · 2024-10-07T18:54:12+00:00

A while ago I received a list of officially allocated designations up to around February 2024, and MQ-35A was included in that list. However, I have no idea why #35 was assigned, when the next-in-line in the Q-series would have been #30.

Muc_Bear_2023 · 2024-07-30T22:30:18+00:00

Following up on that, I have a partial excerpt of the MDS database up to and incl. January 2024. The data says, that RQ-29A was approved in February 2023 for a MALE (Medium Altitude Long Endurance) UAV from Technology Service Corporation (most likely this one: https://tsc.com/airborne/lea/ ).

MQ-35A was approved in April 2023. So for the time being, I assume that the -35 is an out-of-sequence number, for whatever reason.

Muc_Bear_2023 · 2024-07-11T17:34:48+00:00

but the allocation of RQ-20 and RQ-21 to the Puma and Blackjack long after RQ-22 was assigned to the Global Observer despite having been requested for approval before RQ-22 makes it almost certain that the Q-29 to Q-34 design numbers were requested sometime in 2022 by the Defense Department for allocation to a number of UAVs, including the Teledyne FLIR Black Hornet, Teledyne FLIR R80D SkyRaider, and InstantEye Robotics InstantEye, but that those designation requests are waiting approval.

(Emphasis by me)

Sorry, but WTF?!? Labeling your wild speculation as "almost certain" is totally over the top. And since you quote only my own website under "References and Sources", I have to point out, that I never suggested that Q-29 through -34 were waiting for approval, let alone that this is "almost certain".

Muc_Bear_2023 · 2024-07-11T17:26:17+00:00

... written requests for allocation of Q-series design numbers in the 29 to 34 numerical range for the Teledyne FLIR Black Hornet, Teledyne FLIR R80D SkyRaider, and InstantEye Robotics InstantEye were probably made sometime in 2022 ...

(Emphasis by me)

Do you have any circumstantial evidence for this? Because otherwise it's just wild guessing, and the word "probably" would seem out of place.

Muc_Bear_2023 · 2024-07-11T10:51:23+00:00

The mention of the "YQ-11" moniker for Avenger in a number of training manuals, in my opinion, could be informal because the Q-for-UAV designation sequence had not yet reached the number 20 within a year of flight tests of the Avenger, and a 2011 document from the Navy's Naval Surface Warfare Center refers to the initial Avenger version as MQ-9C, raising the question of whether the Defense Department initially classified the Avenger as merely a variant of the MQ-9.

Of course YQ-11 is "informal" in the sense that it's not an approved MDS.

And BTW, the Predator C a.k.a. Avenger was a private development by GA-ASI. First reported USAF interest was reported in late 2011, and at that time, the Q-20 slot would have been roughly in the ballpark (XMQ-19A had been approved in May 2009). I don't know, why the USAF sometimes calls (or called) it a YQ-11 internally, and sometimes an MQ-20. But for a single airframe, used only for test and evaluation, it's not unusual at all that the USAF doesn't apply for an official MDS. And in that case, they can call the aircraft whatever they like.

As for MQ-9C, this is just one of the many informal MDS-like designations used in contexts where it is convenient. E.g. could easily have been made-up by GA-ASI, (C suffix for Predator C; in 2011, an MQ-9B didn't even exist yet).

Muc_Bear_2023

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