Talk:Helicopter

Experimental helicopter by Dr. Boothezaat in 1923

I'm reading through old Time Magazine issues. The March 1923 issue discusses Thomas Edison sending Dr. Boothezaat a congratulations for a test of a helicopter by remaining in the air for 2 min 45 sec at a height of 15 feet. Also see https://time.com/vault/issue/1923-03-03/page/23/. — Preceding unsigned comment added by Noloader (talk • contribs)

Semi-protected edit request on 5 February 2024

I want to edit something because it doesn’t seem right and giving wrong information about helicopters. You should have also all the answer to helicopters

}} 86.49.255.40 (talk) 12:32, 5 February 2024 (UTC)

Semi-protected edit request on 12 June 2024

The following phrase, whilst partially correct, is misleading:

"

Sikorsky's V-300, 1937

Most helicopters have a single main rotor, but torque created by its aerodynamic drag must be countered by an opposed torque"

[Suggested Correction]: Aerodynamic drag affects the entire aircraft. Specifically, the aerodynamic drag experienced by the rotor blades is transmitted to the airframe by an equal and opposite 'reaction torque' via the rotor drive shaft and hence the engine mounts. Unlike an automobile engine, in which the. car body cannot rotate in response to this torque, a helicopter is free to rotate around the rotor drive shaft axis. A tail rotor, 'anti-torque rotor', is therefore necessary to establish a balancing (anti-)torque to prevent the airframe from spinning around the rotor axis.

Suggest the text is amended accordingly. 86.26.142.91 (talk) 10:49, 12 June 2024 (UTC)

 Not done: please provide reliable sources that support the change you want to be made. Lightoil (talk) 15:28, 12 June 2024 (UTC)

New section on transmission design

I noticed that the article does not contain any information on transmission design, which is an important topic for helicopters, so I drafted the following. Since helicopter designs vary so widely, I used words like "usually", "often", and "typically" so it would be clear that not all helicopters share a single design. Please reply with any comments or suggestions. (Note that there is already a subsection within "Saftey" section that discusses transmission safety, see Helicopter#Transmission, but it does not discuss transmission design). Noleander (talk) 15:14, 8 December 2024 (UTC)

Proposed new subsection "Transmission"

The transmission is a mechanical system that transmits power from the engine(s) to the rotors. The transmission is a system of gears, bearings, clutches and shafts that performs several functions (1) Translates the alignment of the drive shaft to match the alignment of the rotor shafts; (2) Reduces the RPM of the drive shaft to the lower RPMs of the rotors; and (3) Enables the engine to engage or disengage from the rotors. For helicopters with tail rotors, the transmission drivetrain forks into two paths: one leading to the main rotor, and one leading to the tail rotor.

The drive shafts of helicopter engines are typically not aligned with the rotor shafts, so the transmission must translate the alignment of the drive shaft to match the shafts of the rotors. Many engine drive shafts are aligned horizontally, yet the main rotor shaft ("mast") is usually vertical, and the tail rotor shaft is often perpendicular to the engine's drive shaft. The transmission contains a series of gears, usually bevel gears, that translate the alignment of the drive shaft to the alignment of the rotor shafts.

The transmission also reduces the RPMs of the engine to the lower RPMs required by the rotors. The output drive shaft of the engine, before any gearing is applied, is typically between 3,000 and 50,000 RPM (turbine engines typically have higher RPM than piston engines). The main rotor typically rotates between 300 to 600 RPM. The tail rotor, if present, usually rotates between 1,000 to 5,000 RPM. (The RPMs of a given model of helicopter are usually fixed — the RPM ranges listed above represent a variety of helicopter models). The transmission contains a series of reduction gears to reduce the engine RPM to the rotor RPMs. Several types of reduction gears may be used, including bevel gears, planetary gears, helical gears, and spur gears. Most transmissions contain several reduction gears: the engine itself may contain reduction gears (often spur gears) between the engine's internal shaft and the output drive shaft; the main rotor may have a reduction gear at its base (typically a planetary gear); and there may be reduction gears at the tail rotor, and on the shaft leading to the tail rotor.

The transmission often includes a clutch, which permits the rotors to engage or disengage from the engine. A clutch is required so the engine can start up and gain speed before taking the load of the rotors. The clutch is also required in the case of engine failure: in that situation, the rotors must disengage from the engine so that the rotors can continue spinning and perform autorotation. Helicopter clutches are usually freewheel clutches relying on centrifugal forces (sprag clutchs are commonly used), but belt drive clutches are also used. Noleander (talk) 15:14, 8 December 2024 (UTC)

This seems very relevant and not an issue to me. You need to pipe a more specific link for transmission in the first sentence, since that is a disambiguation page and not that useful of a link. Regards -Fnlayson (talk) 03:52, 9 December 2024 (UTC)

Thanks for the feedback, I made that change. Noleander (talk) 05:05, 9 December 2024 (UTC)