YF-84F Thunsderstreak

Attached photo of the first of two YF-84F aircraft (51-1344 and 51-1345 are described as pre-production prototypes and considered prototypes of the Thunderstreak). Please note the low rear fuselage and sliding framed Thunderjet style canopy.
My question, however, concerns the serial number. Why has aircraft 51-1344 a B added (FS-344B) on the nose. Isn`t that somewhat unusual?
BTW, aircraft 51-1355 had a solid pointed nose and lateral intakes.

I believe the letter suffix was added when there was already another aircraft with the same buzz code. It is not part of the serial number.

Re: YF-84F Thunderstreak

Thank you Bill for your suggestion. Seems quite possible, but I have my doubts and will try to explain.
Wikipedia mentions 51-1344 and 51-1345 as prototypes (YF-84) for the Thunderstreak and both being modified/converted from F-84G Thunderjets. I could accept that the aircraft may have been built as F-84Gs and than modified as YF-84F prototypes, being a possible reason for putting FS-344B on the nose of 51-1344. But 51-1345 had only FS-345 on its nose, no B added.
Joebaugher has 51-1344/1345 listed as YF-84Fs and the serialnumber are NOT in his F-84G list.
The millionmonkeytheater.com site has detailed productionlists/histories of all F-84 aircraft (but also of many other types) and there 1344/1345 are also only called YF-84Fs and NOT in the F-84G list.
I know there are more important things, but it bugs me I (agreed. just a little bit)

The 7 June 1946 revision of the basic Army Air Force Technical Order (T.O. 07-1-1) addressed "duplicate" buzz numbers:

"If two or more aircraft of the same model with the same last three digits of their serial are assigned to the same unit/base, letter suffixes will be added to the presentation."

"Model" is assumed to be the same as "Mission" (as in MDS), in this case the intent would be to deconflict the Buzz Number from any other fighter aircraft at Edwards AFB, presumably, the suffix would be applied locally.

However, it is also noted that Republic applied the Buzz Number suffixes at the factory (without knowing the serials of other fighters at the user bases) so one can assume that they interpreted the T.O. to apply the suffix to the duplicate Buzz Numbers numbers on all of the F-84s that they were manufacturing.

Believe it or not, there is a book on the subject: "Buzz Numbers: The Explanations and Regulations Behind America's Military Aircraft Identification System" by Peter M. Bowers and David W. Menard.

Now if only those 'mystery ships' - seen over Texas were wearing Buzz Numbers, we could check what they are..

Dear J.A.W. ;D
The use of buzz numbers of the Texas mystery plane(s) would seem somewhat unlogical as the system was intended (to scare of) low flying pilots. Never know this, but very interesting to learn about the origins of the buzz number. Thanks to aim9xray for the tip on the Peter M.Bowers book etc. Quite some info on the net and aerofiles.com also has a list with the buzz number system.

Thank you aim9xray for your info/explanation and the role of Republic Aircraft
Seems only the FS-... buzz numbers (which covered all F-84 aircraft, the Thunderjet, Thunderstreak and Thunderflash after 1948) sometimes had a suffix. Found quite some pics on the net, now that my attention was triggered. Thanks again!!

Just to add to the subject, the YF-96A has been described in various books as the F-84F prototype, while it is obvious that it had the later bubble canopy and a different, earlier serial number (49-2430). According to The Thunder Factory, it was a modified F-84E which "featured an F-84E fuselage, a circular intake, an old-style sliding canopy and an unusual vee-shaped windscreen". On the photos it carried no buzz numbers, only the name "Republic YF-96A" on the nose sides.

Another very interesting photo in that book shows two F-84Ds mated with an ETB-29A. Their buzz numbers are most unusual: EF-641-A and EF-661-A. This indicated the fact they were no longer considered as "Fighters" but as "Exempt" (I can't recall other types using the "E" letter but there should logically have been EA-, EB-, EC-, ED- and EE- types before that). Also the "A" suffix letter is separated from the three-digit number by a hyphen, unlike the FS-344B example quoted in the first post.

Re: YF-84F Thunderstreak

Hi Stéphane
The YF-96A was the first aircraft that externally resembled the later Thunderstreak and as you mention it was modified from a F-84E airframe (keeping the J35 engine as well). The aircraft was later used in the FICON trials and then had downward angled tail planes. I understand that for the FICON programme it was known as RF-84F (no relationship with the Thunderflash!) and that it survives in the USAF Museum collection, still with the inverted V-tail planes. The next two Thunderstreak style aircraft were the YF-84Fs serialled 51-1344 and 51-1345. The first YF-84F (51-1344 with the B suffix), looked much like the YF-96A with the low rear upper decking and sliding canopy. To make things much easier for us airplane researchers, 51-1345 had a solid nose and lateral intakes and if you see photos of YF-84F 51-1345 and the RF-84F prototype flying in formation, they look very much alike. Seems there was never (officially) an XF-84F!(?)
Attached a pic of a T`jet with a buzz number with hyphen. Consistency in the paintwork seemed not a strong point during the late 1940s/early-1950s. Puzzled? take an aspirin (or a glass of a good wine)
Cheers

walter said:

Seems there was never (officially) an XF-84F!(?)

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Actually my own F-list has an XF-84F entry as "former XF-96A redesignated; later became third YF-84F".
Why the YF-96A had a later type, fully glazed canopy as the two "real" YF-84F prototypes that came after it is still beyond me.
Also beyond me is the "A" suffix in the YF-96A designation, which in pre-1962 fashion suggests there must have been an XF-96 or a YF-96 before it, while in fact there doesn't seem to have been anything of the sort...

Re: YF-84F Thunderstreak

Hi Stéphane
To answer your question on the canopy and to make it your problem (sorry), please see the attached pic of 49-4230 with a framed canopy (as YRF-84F Ficon with drooped tail planes). Gone is the clear canopy.
The site of the USAF Museum mentions that 2 additional prototypes were built as XF-84F (51-1344/1345) so the earlier YF-96A (49-2430) could thus have become the first (third?) XF-84F. On the joebaugher site 51-1344/1345 are called YF-84Fs and 49-2430 the XF-96A before becoming XF-84F. Early photos of the first aircraft (as already indicated by you) clearly show YF-96A on the nose.


I will for the time being return to my country house/swimming pool/BBQ and look forward to your news holding all sorts of solutions.

Takeoff shot of YF-96A-cum-YF-84F. -SP

Republic YRF-84F with braced, Thunderjet canopy.

circle-5 said:

Republic YRF-84F with braced, Thunderjet canopy.

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Cool - and wing root engine air inlets. -SP

Here another picture of the YRF-84F Thunderflash:
View: https://flic.kr/p/2oRzwVa

YRF-84F Thunderstreak Thunderflash s/n 51-1828
Prototype Republic YRF-84F Thunderstreak s/n 51-1828, NACA 154, on the ramp adjacent to Hangar 4802 at the NACA High-Speed Flight Research Station in 1954. The one-of-a-kind prototype was flown from 1954 through 1956 to gather research data on the pitch-up phenomenon, a common problem with early swept-wing aircraft

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circle-5 said:

Republic YRF-84F with braced, Thunderjet canopy.

Click to expand...

That photo is actually the second YF-84F prototype, not the YRF-84F.

That YF-84F photo is part of a larger photo that shows both: YF in foreground and YRF in background.
Note the difference in nose shape, YF is pointy, YRF is rather blunt: