Aviation History Writer
- Jan 6, 2013
- Reaction score
I noticed that too!
The Bell/Nord CT.41 received the military designation PQM-56A, so this could be a good place to start looking.Jemiba said: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 ?
It is not quite clear whether D-39 applied only to the L-39 effort or to the whole P-63 program.Tailspin Turtle said:D-39
There have always been two separate systems:jzichek said: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?
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 said:Do you have information about Bell Model-640 ? please.
Model-583 was a test vehicle built and flown.hesham said:I don't know what is this;
Model-583 was a pitch response !?.
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.
C81 was a family of rotorcraft flight simulation programs. See http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA108294hesham said:Model-C81 was also a rotor.
And you're keeping it to yourself?!? Flippin' heck!Steve Pace said: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.
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 said:Oddly though Model numbers 70 thru 100 were not used. Curious as to why?... -SP
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.Steve Pace said:Too many pages to scan and post. I don't have the time.
Makes sense. A few guidelines:Steve Pace said: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
I'll send 10 more next time. -SPStargazer2006 said:
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:Stargazer2006 said: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".
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.Jemiba said: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")
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.Stargazer2006 said: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.
You're right, but as I understand it was assigned, together with Youngs patents to Bell and was used in the developmentTailspin Turtle said: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.
lark said: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
source : Bell aircraft corporation page 376.