Helicopter Rotation Conventions and Helicopter Seating Arrangement

[Super-Hornet]

Ever wonder why U.S, U.K and Italy heli chooses Counter Clockwise rotation why Russia and some French chooses Clockwise?

Found out this URL that explain why:
== http://www.aerospaceweb.org/question...s/q0212b.shtml ==
It is true that there are two consistently opposite trends in the direction the main rotor of a conventional single-rotor helicopter rotates. This difference appears to vary with the nation in which a particular helicopter was designed. When viewed from overhead, American helicopter rotors almost universally spin in a counter-clockwise direction. Many European helicopter rotors, on the other hand, tend to spin in a clockwise direction. However, there are several exceptions to these rules, particularly within Europe.

We confirmed these trends by comparing the rotor designs of a number of different helicopters from around the world. Overhead drawings are especially useful since the way in which the rotor blades are attached to the central hub makes it immediately obvious where the leading edge (LE) of a rotor blade is. Knowing which edge of the blade is the leading edge determines the direction in which the blades must rotate to generate lift. Based on the photos and drawings that we could locate, we found that rotors almost always rotate in the same direction depending on the nation the helicopter comes from. Examples are shown in the figure below.



American helicopters manufactured by companies like Sikorsky, Boeing Vertol, Bell, and MD Helicopters all appear to rotate counter-clockwise like the SH-60 Seahawk illustrated above. The opposite convention is used in all French helicopters built by Aérospatiale, such as the Eurocopter Tigre, as well as all Russian helicopters built by Mil, like the Mi-8. However, the manufacturers in many other European nations use the same convention as the Americans. The helicopters built by Westland in the United Kingdom and Italy's Agusta all rotate counter-clockwise, as exemplified by the EH-101 Merlin and A109. German manufacturers like MBB and the Japanese companies Kawasaki and Mitsubishi also follow the American convention.

We've attempted to investigate how these two opposing philosophies emerged but have yet to find an answer. However, the story about a German twin rotor helicopter being split among the allies seems pretty unlikely. The American design layout with counter-clockwise rotor motion can be traced at least as far back as Igor Sikorsky's R-4 helicopter developed during the early 1940s, several years before the end of World War II. Other American helicopter pioneers like Larry Bell, Stanley Hiller, and Frank Piasecki subsequently employed this convention. Westland in the UK and Agusta in Italy as well as the Japanese manufacturers Fuji, Mitsubishi, and Kawasaki all entered the helicopter market by making licensing agreements to build American designs, so this sharing of technology may also explain how those nations came to adopt the American counter-clockwise rotation.

As for France and Russia, we have been unable to determine how manufacturers in those nations came to use a different convention. The same trends are also followed in countries like Poland, China, and India, probably because firms in these nations have also license-built helicopters from Russia and/or France. Whether the decision to adopt an opposite direction of rotation was made for technical reasons or was simply a matter of preference is unclear. If any readers are aware of the answer, please contact us.
- answer by Joe Yoon, 23 January 2005
================================================== ===

[Super-Hornet]

Helicopter Seating Arrangement

== http://www.aerospaceweb.org/question...rs/q0072.shtml ==
Why are helicopter pilots located on the right side of the aircraft, when all other conventional aircraft have the pilot situated on the left?
- question from Scott Pulcinella

This is one of those basic questions to which no one seems to know the definitive answer, and those who do have an answer usually say little more than an eloquent "just because." Being one who believes that every decision an engineer makes has a reason, I found a more than adequate answer in R. W. Prouty’s booklet More Helicopter Aerodynamics. Some may argue that this view has a decidedly American bias, but given the history of helicopters and the importance of Igor Sikorsky’s contributions, it is understandable that the reasons can be traced to the United States.

The origins of the pilot’s position are a bit vague, and everyone seems to have their own opinion on how it came to be, but there are a couple convincing explanations. You can judge for yourself which explanation you think is the most reasonable. Also, before I get into the details, I should admit that my helicopter history might not be 100% accurate. The dates I have listed are what I have found, but it seems like for every source I find, there is another source that lists a different date.

Les Morris was one of the first helicopter test pilots for Igor Sikorsky, and he had time in the first American helicopter, the VS-300. On the single seat VS-300, which made its debut on 8 December 1941, the collective control was fitted on the left side of the seat (for reasons unknown to me). The next year brought the introduction of the XR-4 helicopter, which was designed to the flown from the left seat (again for reasons I’m not sure of...it is possible that Mr. Sikorsky was trying to follow the convention of fixed wing aircraft). In these early helicopters, the collective controls were always mounted between the seats, unlike modern helicopters, which have collective controls on the left of each seat. Morris, being a good test pilot, retrained himself to fly from the left seat, with the collective in his right hand. In his own words, it took him "many hours before I mastered an inordinate desire to use the wrong control at the right time!" Once he had retrained himself, Morris began training other pilots in the XR-4. Morris, however, didn't want to give up the left seat and risk confusing the controls should a student pilot make a mistake that required a quick correction, so all the new pilots were trained in the right seat. From this point on, all new helicopter pilots learned to fly from the right seat, which is one possible explanation for their position in modern helicopters.

Some may find it hard to believe that this one man's seating preference was enough to influence the standards of the entire helicopter industry. A few years after Morris' early impact, after helicopters had been in use in the military for a few years, a poll was taken of many U.S. Navy, Marine, and Army helicopter pilots. This poll revealed that the majority of military helicopter pilots preferred to fly from the right seat, for several reasons, including manipulation of the other controls, the placement of the rescue hoist on the right side of the helicopter, and the aircraft carrier environment. Some of these reasons are a bit sketchy, and some may be a "chicken and the egg" type of issue. It is very possible that the rescue hoist was placed on the right side because of the location of the pilot's seat, not the other way around. Of course, there are plenty of helicopter history "experts" that would tell you that the pilot sits on the right side "just because."

Personally, I tend to think that the early test pilots using the left seat to train the new guys played a major role in the location of the pilot’s seat, and that it sounds most reasonable that the rescue hoist was placed as a result of this decision. Unfortunately, that is only my personal opinion, and shouldn't be taken by anyone to be any more truthful than someone else’s "just because" explanation!
- answer by Doug Jackson, 7 April 2002

[Adrianli]

Wow, so many words. Didnt bother to read. Can surmarise for me???

[Super-Hornet]

In summary:
U.S., U.K. and Italy adopt CCW
Russia adopt CW
French... cannot decide which one.

Initially, when heli started, the instructor seat on the left and teach all pilot who seat on the right. So now, all pilots are train to fly on the right.

SH

[Super-Hornet]

Found another simplified info about the rotor rotation:
Main rotor can certainly rotating clockwise, clockwise or anti-clockwise, not between good or bad. Interestingly, the United States, Britain, Germany, Italy, Japan helicopter main rotor are counter-clockwise rotation, France, Russia, China, India and Poland are helicopters clockwise rotation, Britain, Germany, Italy, and the helicopter industry are imported from the United States permits the beginning, and the United States adopt the same the habit can understand that China, India, Poland and the former Soviet Union began to permit the introduction of France, and France, Russia and the same habits can be understood, but why the United States and Russia from the beginning selected a different direction, why not France and the United States elected the same direction, and Russia agreed. history may just be a joke.

[wilson76]

btw, heli pilots able to fly on both side. Basically Co-pilot on left seat while the pilot is on Right seat.

In summary:
U.S., U.K. and Italy adopt CCW
Russia adopt CW
French... cannot decide which one.

Initially, when heli started, the instructor seat on the left and teach all pilot who seat on the right. So now, all pilots are train to fly on the right.

SH

[wilson76]

Aerodynamically there is no explaination or any advantages to why manufacturer design CCW or CW on their rotor dynamic. From pilot perspective, you have to be aware of the yaw direction of the aircraft if you flown US and french heli. You might realise you will input wrong pedal(rudder) controls in countering yaw.

Found another simplified info about the rotor rotation:
Main rotor can certainly rotating clockwise, clockwise or anti-clockwise, not between good or bad. Interestingly, the United States, Britain, Germany, Italy, Japan helicopter main rotor are counter-clockwise rotation, France, Russia, China, India and Poland are helicopters clockwise rotation, Britain, Germany, Italy, and the helicopter industry are imported from the United States permits the beginning, and the United States adopt the same the habit can understand that China, India, Poland and the former Soviet Union began to permit the introduction of France, and France, Russia and the same habits can be understood, but why the United States and Russia from the beginning selected a different direction, why not France and the United States elected the same direction, and Russia agreed. history may just be a joke.

[tucfaz]

Guess it may be simply a left hander and right hander thing.. or a left hand drive or right hand drive car.. Some feel more at ease doing side hover to the right (right hander maybe), some can do it better to the left.

So maybe it all started with a left handed engineer who simply make the rotor rotate base on his habit.. then evolve, while others may just follow, where some will create their own, like US will never follow the Russian, or vise versa..

[kiratime]

In summary:
U.S., U.K. and Italy adopt CCW
Russia adopt CW
French... cannot decide which one.

Initially, when heli started, the instructor seat on the left and teach all pilot who seat on the right. So now, all pilots are train to fly on the right.

SH

this explains y aurora spin couunter clock wise

[Super-Hornet]

Corona is from U.S. and it is CCW also.

SH

[temannis]

Hi Sh.

Do you have information on the different type of tail rotor configuration? Some heli using tractor scheme whereby the tail rotor wash flow over the tail fin and boom. And some uses pusher type like the one in RC heli, with the rotor wash directed away from the fin and boom.

[Super-Hornet]

I don't have but I can tell u the differences:

Having pushing type of configuration is more efficient and more powerful than pulling. The reason is that the downwash from tail rotor is not block by the tail fin.

All U.S. heli spin CCW so, to have pushing configuration, the tail is on the left. Same thing goes for CW rotation heli with tail rotor on the right.

There are some exception cases though. In Super SeaStallion, the tail rotor is mounted on the left and is inline with the horizontal fin/tail section but whole tail section is tilted at an angle (blow downward) in order to achieve some lift for the tail. In Black/Pave/Sea/Jay Hawk, it is doing the same thing of providing some tail lift by tilting the tail rotor. Because the tail section/fin is straight, in order to have tilted tail rotor, it is mounted on the right side instead.

There are some Huey and Cobra that has its tail rotor on the right (pulling) and some on the left. Why they have different combination, I not sure.

SH

[temannis]

I don't have but I can tell u the differences:

Having pushing type of configuration is more efficient and more powerful than pulling. The reason is that the downwash from tail rotor is not block by the tail fin.

All U.S. heli spin CCW so, to have pushing configuration, the tail is on the left. Same thing goes for CW rotation heli with tail rotor on the right.

There are some exception cases though. In Super SeaStallion, the tail rotor is mounted on the left and is inline with the horizontal fin/tail section but whole tail section is tilted at an angle (blow downward) in order to achieve some lift for the tail. In Black/Pave/Sea/Jay Hawk, it is doing the same thing of providing some tail lift by tilting the tail rotor. Because the tail section/fin is straight, in order to have tilted tail rotor, it is mounted on the right side instead.

There are some Huey and Cobra that has its tail rotor on the right (pulling) and some on the left. Why they have different combination, I not sure.

SH

Thanks! No wonder my heli don't have strong tail hold, cos it is using tractor type.

[Super-Hornet]

What heli are u referring to that do not have tail authority?
Your Honey Bee or your Hirobo?

SH

[AceViperX]

Aerodynamically there is no explaination or any advantages to why manufacturer design CCW or CW on their rotor dynamic. From pilot perspective, you have to be aware of the yaw direction of the aircraft if you flown US and french heli. You might realise you will input wrong pedal(rudder) controls in countering yaw.

Doesn't the rudder work the same irrespective of the rotation of the rotor?