No such thing as a Bell 540. And as far as the rotor system goes, I thought it was called the "680 rotor system."
I can't even see how a 540 fits in the Bell naming convention. The MAPL series were all 3s (351, 381, 382) for third generation. But that was an engineering model referencing. The only thing to come out of MAPL has been the 429 which is the MAPL 382 airframe, MAPL rotor blades, with 427 powerplant and newly designed drive system, hub, and tail rotor.
Mind you the Bell model-naming convention defies convention. About the only consistent thing has been that the first digit correspond to the number of blades. At times there has been reference to pax (i.e. the 609 has 6 blades and carries 9 people, a 412 has 4 blades carries about 12 pax. ) Sometimes the number includ the crew, sometines it doesn't Sometimes Bell thinks its Boeing and starts to sequence just the center digit (i.e. 407, 427, 417). Sometimes it has added digits in normal counting fashion, but that was back in the 60s and 70s. i.e. 204,205 to 206, 209 was the Cobra, then 212, 214, etc. I think there were models in between the gaps - being variants that were prototypes or didn't make it. But then the 206 became the 406 for 4 blades (OH-58) then it evolved to become the 407. But when the 407 was evolved into a twin, and a "2" was inserted in the middle to make it a 427. Actually, I think the "222" evolved in sequence, but then it somehow progressed to the "230" as a single step (why add 8??) and then became a 430 when it went to 4-blades.
The initial improvements to the 427 were supposed to be called the 428. But that number is considered bad luck in some cultures, so it was initally dubbed the 427s3i (That's how it was displayed at HAI 2004. Ask Sandy Kinkade the story behind that some time.
) In 2005, when it took on the MAPL airframe, it became the 429.
So by logic, a 540 would be five-bladed and carry 40 people, or have 4 engines and carry 0 people, or be the 40th design in a 5-bladed family of designs....
