Bell Aircraft and Helicopter Designations

[Steve Pace]

I noticed that too!

 

[Apophenia]

Scott's list (well, up Model 69) transcribed for 'searchability'.

Model 1 -- XFM-1 Airacuda
Model 2 -- Consolidated XA-11A (A-11 re-engined with Allison V-1710)
Model 3 -- single-seat fighter project, tricycle landing gear, engine ahead of cockpit.
Model 4 -- single-seat fighter project, tricycle landing gear, engine behind cockpit.
Model 5 -- XFL-1 Airabonita carrier fighter.
Model 6 -- radio-controlled A-7 Airacobra proposal for the Army
Model 7 -- YFM-1 Airacuda, 7B YFM-1B
Model 8 -- YFM-1A Airacuda (tricycle gear)
Model 9 -- Airacuda development as attack bomber
Model 10 - Airacuda development as attack bomber
Model 11 - XP-39
Model 12 - YP-39
Model 13 - Airacobra to R-40C competition (V-1430-1), 13A (V-1710-E8), 13B (V-1710-E9)
Model 14 - P-400, 14A - P-400, 14A-1 - P-39D-2
Model 15 - P-39D, Model 15B - P-39F and P-39J
Model 16 - XP-52
Model 17 - XFM-1C Airacuda attack bomber
Model 18 - two-seat tandem, low-winged trainer project
Model 19 - XP-52 variant for USN
Model 20 - XP-59 (twin-boomed pusher)
Model 21 - single-seat naval fighter ('hooked' P-39)
Model 22 - XP-59 twin turbojet fighter
Model 23 - XP-39E (laminar-flow winged Airacobra)
Model 24 - XP-63 and XP-63A Kingcobra
Model 25 - P-63A Kingcobra
Model 26 - 26A - P-39K, 26B - P-39L, 26C - P-39N-1 26, C-5 - P-39N-5/N-6, 26D - P-39M,
26E - P-39Q-5, 26E-10P-39Q-10, 26E-15 - P-39Q-15, 26E-21 - P-39Q-21, 26E-25 - P-39Q-25, 26E-30 - P-39Q-30, 26F - P-39N-0
Model 27 - XP-59A , YP-59A, and P-59B twin-turbojet fighters
Model 28 - 28 and 28A - P-76 (production models of XP-39E) - cancelled, replaced by P-39M
Model 29 - XP-59B (project, single-turbojet fighter)
Model 30 - 1942 helicopter (3 built, basis for Model 47)
Model 30 - repeat designation, bomb tail (Type B-3 Tarzon)
Model 31 - [not used]
Model 32 - XP-77 light fighter-bomber
Model 33 - P-63A-1, 33A-5 - P-63A-5, 33A-6 - P-63A-6, 33A-7 - P-63A-7, 33A-8 - P-63A-8, 33A-11 - P-63A-11 trainer, 33A-12 - P-63A-12 trainer, 33C-1 - P-63C-1, 33C-2 - P-63C-2 trainer, 33C-5 - P-63C-5
Model 34 - XP-63B (Packard Merlin), study contract only, never built
Model 35 - XP-77A interceptor project
Model 36 - single seat fighter project (twin Chrysler engines)
Model 37 - P-63D-1 (bubble canopy Kingcobra)
Model 38 - TP-63A two-seat trainer
Model 39 - TP-39 two-seat trainer
Model 40 - XP-83 twin-turbojet escort fighter
Model 41 - P-63E
Model 42 - 1946 5-seat helicopter (3 built)
Model 43 - P-63F (Kingcobra for the French)
Model 44 - X-1
Model 45 - XP-63H, proposed 'E-1 conversion to test Allison V-1710-127 (E-27) turbocompound
Model 46 - 2-seat helicopter (Lycoming)
Model 47 - 2-seat helicopter
Model 48 - H-12, 5-seat helicopter
Model 49 - 2-seat coaxial helicopter
Model 50 - Convert-O-Plane
Model 51 - army liaison helicopter
No Desig - swept-wing L-39 testbed
Model 52 - X-2
Model 53 - P-63A-9 Kingcobra two-seater (mod. for company use)
Model 54 - XH-15, 2-seat helicopter
Model 55 - Meteor I missile
Model 56 - XB-63 pilotless parasite bomber
Model 57 - rocket propusion system for Torpedo M-13
Model 58 - X-1A/B/C/D
Model 59 - X-9 Shrike - GAM-63 Rascal testbed (Aerojet/Solar engines), 59A - Bell engines
Model 60 - X-5 variable-geometry wing research aircraft
Model 61 - XHSL-1 ASW helicopter
Model 62 - B-63 pilotless parasite bomber
Model 63 - bomb tail, Trizon
Model 64 - Meteor II missile
Model 65 - "ATV" (VTOL testbed for X-14)
Model 66 - B-63A/GAM-63A Rascal missile
Model 67 - X-16 reconnaissance aircraft
Model 68 - X-14 VTOL research aircraft
Model 69 - BDM (bomber defense missile)
Model 70 - to - Model 100 [not used]

 

[hesham]

The Bell Model 217G was not helicopter,

it is as I think a gearbox or something else,here is an info
about it through Model 208;

the Model 208 was basically a UH-1D re-engined with a Cont.
XT67-T-1 free-turbine power plant,comprising two T73-T-2
Model 217 turboshafts couple to a common reduction gearbox
and output shaft.

 

[Jemiba]

In InterAvia N° 5, 1960 it was mentioned, that Bell reached a license agreement with
the french Nord-Aviation about production of the supersonic target Nord CT.41, so
it maybe got a Bell designation number ?

 

[Stargazer]

In InterAvia N° 5, 1960 it was mentioned, that Bell reached a license agreement with
the french Nord-Aviation about production of the supersonic target Nord CT.41, so
it maybe got a Bell designation number ?

The Bell/Nord CT.41 received the military designation PQM-56A, so this could be a good place to start looking.

D-39

It is not quite clear whether D-39 applied only to the L-39 effort or to the whole P-63 program.

 

[jzichek]

My confusion concerns the Model 68 designation for the X-14 demonstrator. Is that the same as D68 (which is a number way back in the queue) or did Bell have two internal designation systems - a "D" series for studies and a "Model" series for aircraft that actually flew?

 

[Stargazer]

My confusion concerns the Model 68 designation for the X-14 demonstrator. Is that the same as D68 (which is a number way back in the queue) or did Bell have two internal designation systems - a "D" series for studies and a "Model" series for aircraft that actually flew?

There have always been two separate systems:

1°) the two-digit "Models" series which began in the 1930s with the Model 1 Airacuda (U.S. Army Air Corps XFM-1), and ended with Model 69, circa 1957 (a subcontracting work for General Electric on the Bomber Defense Missile (BDM) program. There was also a 3-digit system with Models 100 to 130 used for subcontracting work, and 200 up for rotorcraft. Eventually only the latter continued to be used, in non-sequential order ("200" being usually reserved for twin-blade helicopter designs, "400" for four-blade designs).

2°) the "Designs" series which began during the War. The earliest known is D-6, which corresponds to the Model 32 or XP-77). These appear with or without the hyphen depending on documents. Apart from the non-sequential D-400 (1956), D-400A (1958) and D-600 (the program that led to the AB609) the sequence was chronological, with the highest known number being D-340 (the Pointer tilt-rotor UAV). Bell also used a four-digit system starting in 1959: in the "1000" series I only know of D-1007 (a huge nuclear-powered double-deck twin-rotor project). The "2000" series was used throughout the 1960s, mainly for the Bell Aerosystems divisions (at least up to D-2447); the "7000" series was used mostly for space-related projects, but also a few air cushion vehicles; the "8000" series was used for engines; the "9000" series was also used at times. I'm still trying to understand the logic of it all myself!!

 

[Stargazer]

I might add (to answer your question more precisely) that, yes, the "Model" numbers usually refer to built types, while the "Design" numbers correspond to unbuilt types or are used before the type becomes a model. However, as usual there have been exceptions and inconsistencies: Models 215 and 216 were unbuilt attack proposals; Models 266 and 300 (which started off as D-266 and D-300) were the unbuilt predecessors of the Model 301 (also D-301) or XV-15. The "600" model series is full of unbuilt tilt-rotor types; the 940A was also a tilt-rotor project.

Reversely, the D-292 was the ACAP prototype and retained a "D" designation with no apparent model number allocation; the X-22A was only known as the D-2127; the SK-3 Carabao ground effect machine and all the other boats or air cushion vehicles used only D-**** type designations.

Oh, and did I mention this? The D-188A (unofficially known as the "XF-109") was actually given a real model number? The only known FOUR-digit Bell model, the 2000... What a mess!!!

 

[jzichek]

Thanks Stargazer, that clarifies things nicely. One thing I have also noticed is the inconsistency with the hyphens in the designations - sometimes its D188, other times D-188, etc. I go with the hyphenless version, as that seems more common.

 

[hesham]

I don't know what is this;

Model-583 was a pitch response !?.

http://www.dtic.mil/dtic/tr/fulltext/u2/767239.pdf

 

[Stargazer]

No. It is a graphic depicting the pitch response of Model 583!! The 500-series contains rotors and rotor-related studies. The Model 533 or YH-40BF high-performance development of Model 204 is there because it is a rotor program. There are also the Model 540 two-bladed door-hing type rotor and Model 599 Bell Rotor Aerodynamic Method for instance.

 

[Stargazer]

Do you have information about Bell Model-640 ? please.

To the best of my knowledge there has never been a "Bell 640." There was, however, a Bell 646 (the RSRA proposal against Sikorsky's S-72) and a Bell 680, a four-blade bearingless rotor system.

 

[hesham]

I don't know what is this;

Model-583 was a pitch response !?.

http://www.dtic.mil/dtic/tr/fulltext/u2/767239.pdf

Model-583 was a test vehicle built and flown.

Model-609 was a rotor.

Model-C81 was also a rotor.

http://www.dtic.mil/dtic/tr/fulltext/u2/a007953.pdf

 

[Stargazer]

Thanks. Here are excerpts that relate to Bell hingeless rotor design history, and specifically refer to the Models 583 and 609 (the C 81 is all over so I left it out). There was heavy proof-reading to be done, as the original photocopy was poor and NASA's OCR was lame as a result.

Bell Hingeless Rotorcraft

Bell Helicopter Company, Fort Worth, Texas, began experimenting with hingeless rotors in the late 1950's. A Model 47 J was first modified to replace the teetering rotor with a three bladed hingeless rotor, 33 ft in diameter, which had flap bending flexures between the hub and feathering hinges. The flexures were subsequently removed and the diameter of the rotor was reduced to 31 6 ft, resulting in a "stiff inplane, stiff hub" conhiguration. This rotorcraft was flight tested by NASA in 1962, and Huston and Tapscott reported (ref. 2.34) substantially increased control power and damping. Although the test rotor was fabricated from standard teetering rotor components, the flight loads remained within the design fatigue loads. About 50 flight hours were logged on the various three bladed hingeless rotor configurations of the Model 47 and XH-13H. In 1962, Bell built a larger three-bladed hingeless rotor (42 ft in diameter) from standard UH-1B hub components and modified 21 in. chord blades. This rotor had flap bending flex elements between hub and feathering hinges and falls in the category "stiff inplane, soft flapwise hub." The modified UH 1B helicopter was flown to 151 knots. The same rotor was fitted in 1963 to a commercial Model 204B fuselage, and blade root cuffs were added to reduce rotor power.

In 1964, a four-bladed hingeless rotor, 44 ft in diameter, again featuring the soft flapwise hub, was fitted to the commercial Model 204B helicopter and flown to 150 knots in a slight dive. In 1965, this rotor was evaluated on the Army Bell high performance compound vehicle with fixed wing and auxiliary let propulation. The vehicle was flown to 196 knots but exhibited a high 4'rev vibration level at that speed. In 1966, the diameter of the four bladed rotor was extended by an inboard nonfeathering housing to increase the lifting capability of the rotor. Both 10° twist and 6° twist blades were available. A flight speed of 130 knots was achieved. Hovering maneuvers gave the critical loads in the mast, limiting the offset c.g. capability In 1968, the same rotor was installed on the T-55 powered Model 583 test vehicle and flown to 147 knots at 9,000 lb and to 138 knots at 12,000 li gross weight. The standard Bell electronic stability ad control augmentation system (SCAS) was also found to work well with the hingeless rotor by reducing gust response and improving phugoid-mode stability. In 1969, an improved version of the four bladed, 44 ft diam. rotor with 6° twist and thin blade tips was installed on the high-performance compound helicopter and used in the High Mach Number/High Advance Ratio Flight-Test Program. Flight speeds up to 220 knots were achieved with the hingeless rotor and a teetering rotor was tested to 274 knots. Maneuvers of 1.8 g were performed with the teetering rotor at 226 knots and maneuvers of 2.3 g were performed with the hingeless rotor at 200 knots. About 70 flight hours were accumulated on the various four bladed hingeless rotor configurations up to 1969.

In 1969/71, a four-bladed hingeless rotor, 48.3 ft in diameter, was designed and built. It featured a forged titanium rotor hub with integral flexures, stainless steel blades, and automatic electrical scissors folding of the two blade pairs for ground storage. This rotor had flown for 127 flight hours as of July 1, 1973, reaching speeds of 150 knots. The gross weight of the test vehicle is 14,000 lb, and it is powered by a T-55-L7B/-7C engine of 2250-hp normal rated power. The blades have 21 in. chord and 9° twist. The mast is installed with 3° forward and 2° left tilt. Flight-test results with this latest Bell soft flapwise hub, stitf inplane Model 609 rotor are reported in reference 2.24. Other publications related to the Bell hingeless rotor developments are references 2.25 to 2.36. Figure 2.3 shows the rotor hub and blade attachment of the Model 609 rotor system. The blade flap frequency at normal rotor speed is 1.05Ω, the first blade inplane frequency for cyclic modes is 1.4Ω, and the blade Lock number is 5.5.

(...)

The main advantages of hingeless rotors - reduced maintenance, fewer hub parts, and improved control response - can be realized with soft flapwise blades, and the trends of many flight dynamic characteristics are unfavorable with increasing blade flap bending stiffness. Therefore, it appears that the design goal should be to reduce the flapwise stiffness (or the fundamental blade flap frequency) to the minimum value consistent with the structural requirements of adequate margins for the most severe trim, gust, and maneuver conditions. An interesting comparison provided by Bell Helicopter Company shows that, for the earlier Bell hingeless rotors, the flexure fatigue stress endurance limit was reached for a flapping angle of 1.5° to 2°, while the latest Model 609 Flexbeam rotor has an allowable flapping angle of 4° — about the same as for the Lockheed AH-56A helicopter.

(...)

Tests with Bell Model 583 with a four-bladed hingeless rotor have shown that a conventional SAS [Stability Augmentation System] can improve the flying qualities of hingeless rotorcraft. Similar observations were made with the Westland Lynx helicopter. However, no quantitative, analytical, or flight-test results of the effectiveness of an SAS have been published for either of these hingeless helicopters.

 

[Tailspin Turtle]

Model-C81 was also a rotor.

http://www.dtic.mil/dtic/tr/fulltext/u2/a007953.pdf

C81 was a family of rotorcraft flight simulation programs. See http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA108294

 

[hesham]

Here is the Bell Model-576;


http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19850019542_1985019542.pdf

 

[Steve Pace]

I have an official Bell Model Numbers document that I acquired many years ago from public affairs. It runs from Model 1 thru Model 6262. Oddly though Model numbers 70 thru 100 were not used. Curious as to why?... -SP

 

[Stargazer]

I have an official Bell Model Numbers document that I acquired many years ago from public affairs. It runs from Model 1 thru Model 6262.

And you're keeping it to yourself?!? Flippin' heck!

Oddly though Model numbers 70 thru 100 were not used. Curious as to why?... -SP

Well, you have to keep in mind that the 1 to 100 list was for aircraft. A few helicopters found their place there before the 200+ series was created, but after that, it was all fixed-wing projects. Since Bell Aircraft stopped doing fixed-wing aircraft, they stopped using that list, period.

 

[Steve Pace]

Too many pages to scan and post. I don't have the time. Looking at it closer - it goes to Model 130 - skipping Models 70-100 and 200-299 (200-299 reserved for Helicopter Division) - begins again with Model 2000 thru 2551 - then begins again with Model 6001 thru 6262 and ends there. There's no models listed 3000 thru 6000. -SP

 

[Stargazer]

Too many pages to scan and post. I don't have the time.

I can understand... But did you consider using a digital camera? I've had good results on documents with a camera and a properly lit room. It would go faster and you could start with the first 70 models.

Looking at it closer - it goes to Model 130 - skipping Models 70-100 and 200-299 (200-299 reserved for Helicopter Division) - begins again with Model 2000 thru 2551 - then begins again with Model 6001 thru 6262 and ends there. There's no models listed 3000 thru 6000. -SP

Makes sense. A few guidelines:

1°) The model numbers.

• The initial series started at Model 1 and was chronologically sequenced. It stopped at Model 69 in 1957.
• Model 101 up were for modifications of existing aircraft and subcontracting work. I don't have any beyond 130.
• Models 200-299 were indeed reserved for helicopters but haven't been used sequentially. They are for helos with two-bladed rotors.
• Models 300-399 may have been reserved originally for convertiplanes, but many have been used for helicopters.
• Models 400-499 are also for helicopters, more specifically the ones with 4-bladed rotors.
• Model 500-599 have seldom been seen; they seem to deal with experimental work, mechanical elements and all sorts of things!
• Models 600-699 mostly include convertiplanes but there are a few helos there too. Confusing!
• Models 700-799 don't seem to have been used.
• Models 800-899 don't seem to have been used.
• Models 900-999 seem to be reserved for convertiplanes.
• Models 1000 and beyond don't seem to have been used, except for the Model 2000 (the D-188A or F3L).

2°) The "D" designs.

• They began some time around 1942 and ran sequentially in chronological order. Last one I know is D340 from 1988 but there could have been more.
• A few out of sequence numbers were allocated along the way, such as D400/A or D600, but these are exceptions.
• The D- numbers do not normally correspond to model numbers, but there have been cases when one led to the other (D266 and D301 becoming Models 266 and 301 for instance).

3°) The four-digit designations.

• The system ran in parallel to the main D-series and started some time in 1957.
• They only carried the D- prefix if there is an actual aircraft or vehicle design. Sometimes they are just report numbers.
• (D)1000-1999 were mostly unused, though there was a D1007 which was a huge nuclear-powered helicopter project.
• The designations (D)2000+ contained mainly VTOL work and went at least up to D2447. It's not clear why they were used in parallel to the main D-series.
• The designations (D)3000+ don't seem to have been used.
• The designations (D)4000+ and (D)5000+ don't seem to have been used much, but there are a couple of examples known.
• The designations (D)6000+ are unknown to me so I'd be very curious to see your list about them, Steve!
• The designations (D)7000+ seem to have been reserved mostly for space-related work, but ground effect vehicles are also found.
• The designations (D)8000+ have been used a lot for rocket work, but there are also helicopter-related reports.
• The designations (D)9000+ were used for a wide range of studies.

All in all, I must say I'm still pretty puzzled about the whole system. I suspect the different lists may correspond to various company sites and design bureaus, but we'd need confirmation. Your document may well shed some light on that, Steve... (hint hint).


NOTE: A separate topic now deals with the "D-" designations AND four-digit numbers:
http://www.secretprojects.co.uk/forum/index.php/topic,21303.0.html

 

[Steve Pace]

Here's the first 8 pages... -SP

 

[Steve Pace]

Two more for now to make 10 pages this entry - more to follow tomorrow and so on... SP


[NOTE.—Page 11 added here.—Mod.]

 

[Stargazer]

Thanks Steve. Though it seems to be the same document that was posted previously in the thread, the scans are much better quality.
Can't wait to see the next installments! (we only had the first eleven pages).

 

[Steve Pace]

Thanks Steve. Though it seems to be the same document that was posted previously in the thread, the scans are much better quality.
Can't wait to see the next installments! (we only had the first eleven pages).

I'll send 10 more next time. -SP


[ NOTE.—The rest of the list concerns the D- designations and 4-digit numbers and can now be found in a separate topic here:
http://www.secretprojects.co.uk/forum/index.php/topic,21303.msg164047.html#msg164047 ]

 

[Stargazer]

The Model 40 (XP-83) is sometimes refered to as the "Airarattler", while the Model 52 (X-2) is sometimes refered to as the "Starbuster" and the Model 60 (X-5) as the "Interceptor".

While "Starbuster" seems to be the invention of a model company (unless of course someone can come up with a document that proves different), "Airarattler" is pure invention as can be read here:

http://www.secretprojects.co.uk/forum/index.php/topic,7843.msg146634.html#msg146634

Please make sure to remove that name from all your personal folders and lists so that the mistake stops spreading!

 

[Jemiba]

Though not a full size aircraft and probably never given a real designation, it was a flying vehicle
built by Bell: An electrically powered and remotely controlle flying model, used in the development
of the first Bell helicopter. It already was fitted with a gyroscope to achieve directional stability.
The model could be used or testing autorotational characteristics. Other models were built, too,
but this one was the largest with rotor of 5 feet diameter. The photo below shows Arthur Young
controlling it outside the barn, that was used as workshop. The cutout is rom the same photo
(from Jay P: Spenser "Whirlybirds")

 

[patvig]

...
D-200 turbine powered convertiplane (not sure)
...

For D-200 I recorded XV-3; source unknown. This could confirm one of Stargazer hypotesis.

 

[hesham]

OK Patvig,I just want to know the source.

 

[Stargazer]

In my notes, collected an assembled over the years, I have the D200 of 1951 as a gas turbine-powered helicopter project and the Model 200 Convertiplane of 1953 which is described as a two-place single engine, research aircraft, studied in both two-blade and three-blade versions; it was ordered as the XH-33 and eventually built as the XV-3.


Therefore two different projects. Thanks to Tailspin Turtle for correcting me on this one.

 

[Tailspin Turtle]

Though not a full size aircraft and probably never given a real designation, it was a flying vehicle
built by Bell: An electrically powered and remotely controlle flying model, used in the development
of the first Bell helicopter. It already was fitted with a gyroscope to achieve directional stability.
The model could be used or testing autorotational characteristics. Other models were built, too,
but this one was the largest with rotor of 5 feet diameter. The photo below shows Arthur Young
controlling it outside the barn, that was used as workshop. The cutout is rom the same photo
(from Jay P: Spenser "Whirlybirds")

As far as I know, this model was built and flown by Arthur Young before he joined Bell, so it would not have had a Bell model number.

 

[Tailspin Turtle]

In my notes, collected an assembled over the years, I have the D200 of 1951 as a gas turbine-powered helicopter project and the Model 200 Convertiplane of 1953 which is described as a two-place single engine, research aircraft, studied in both two-blade and three-blade versions; it was ordered as the XH-33 and eventually built as the XV-3. There is no certainty that the D200 and Model 200 were actually connected though it seems a likely possibility.

At least in later years at Bell Helicopter, Engineering assigned design numbers to studies/predesigns projects and maintained a log of them. Only "management" could assign a model number to a project, which was generally only done for those that Bell was planning or hoping to turn into a product. Management could use engineering's design number as the model number if there was a good (e.g. marketing) reason to do so.

 

[Jemiba]

As far as I know, this model was built and flown by Arthur Young before he joined Bell, so it would not have had a Bell model number.

You're right, but as I understand it was assigned, together with Youngs patents to Bell and was used in the development
of the first Bell helicopter.

 

[Stargazer]

Just happened on a mention that seems so wacky it could be true:

"AH-1RO Dracula: Derivative of AH-1W for Romania, which intended to purchase initial batch of 96. Project abandoned by Bell in fourth quarter of 1999."

Now does that ring a bell to anyone or was someone just having fun?!?

 

[Stargazer]

This topic was becoming pretty long so I split it into three:


This here topic deals with the main model designations series
(Models 1 to 68, 100 to 117, 200 up) and all general discussions on Bell's numbering systems.


A separate topic deals with the "D-" designations and four-digit numbers:
http://www.secretprojects.co.uk/forum/index.php/topic,21303.0.html


A third topic is concerned only with the "Dyna-Soar"-related designations from Bell, but also Martin and Boeing:
http://www.secretprojects.co.uk/forum/index.php/topic,21306.0.html

 

[Stargazer]

L-39 - an explanation.

The U.S.Navy manufacturers identification code for Bell was he letter 'L'.
(see Airabonita XFL-1)
The Navy adopted the Bell 'design number' for the P-63 which was D-39.
Since only the number was used by the Navy they came to L-39 for the swept winged
experimetal P-63.

source : Bell aircraft corporation page 376.

Interesting. Actually the same thing happened with the Convair SeaDart program, which for a long time was designated Y2, since it was Convair's Model 2 and "Y" was the letter used by the Navy for Consolidated and then Convair.

 

[Stargazer]

Posting here below an incomplete but interesting list of Bell's model numbers up to Model 53, reorganized as one single page from the Schiffer book Cobra! (courtesy of lark).

 

[hesham]

Hi,


this Bell Model 47G-2 "Wing Ding" was given the designation Model-548;


http://www.aviastar.org/helicopters_eng/bell_47-wingding.php
http://arc.aiaa.org/doi/abs/10.2514/3.43742

 

[Stargazer]

Nice bit of info, I didn't know that, thanks.

 

[RAP]

Photo dated 1995. Back is marked Bell wheel-gear AH-1W/AH-1-4BW proposal.

 

[hesham]

From Air Pictorial 3/1957,

a strange Info about Bell Model-216 as a three engined helicopter Project,and that make
me confuse,because as we know the Model-216 was attack helicopter ?.