Helicopters - Right-hand-drive bias. Why?

Rgbeard

Rgbeard

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I was asked this by a friend, and had no answer.

Most airplanes are designed as are a majority of vehicles to be left-side biased for pilot/copilot.

However, many helicopters seem to be right-side biased.

Why?
 
So the pilot can have their RH on the cyclic and share a center mounted collective with the copilot.


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Rgbeard said:
I was asked this by a friend, and had no answer.

Most airplanes are designed as are a majority of vehicles to be left-side biased for pilot/copilot.

However, many helicopters seem to be right-side biased.

Why?
Click to expand...

The collective is left hand. By placing the PIC seat right, the collective is on the left, which makes controls easier to route to the rotor head.

There are left seat PIC helicopters. Bell 47G, HU-269B and C, HU-500C, Enstrom are a few examples.

Left Hand PIC in a helicopter is also handy when doing external load work.
 
Rgbeard said:
I was asked this by a friend, and had no answer.

Most airplanes are designed as are a majority of vehicles to be left-side biased for pilot/copilot.

However, many helicopters seem to be right-side biased.

Why?
Click to expand...
For one thing, I have a left handed coffee cup.
 
Rgbeard said:
Why?
Click to expand...
The story I was told through Paul Smith, one of the original Sikorsky R-4 pilots, was that the R-4 only came with one collective so the student pilot sat in the right seat in order to have better control over the cyclic/collective. The R-6 also had a single collective. By the time the Bell 47 and other subsequent models came out, all which had dual collectives, it became more an optional preference where the PIC sat. However, by then you had an entire "1st generation" of helicopter pilots in the US AAC, Navy, CG and UK Royal Air Force/Navy who had only flown from the right seat. So it sort of became the unofficial/preferred side to put the PIC as those original pilots expanded into the rotorcraft field.
 
Seriously, some helicopters have cockpits much wider than airplanes. Once, arrived early for my sim session at Flight Safety, I checked out the cockpits of the Lear, Piagio Avanti and Sikorski/Sikorsky. The "Igor" is at least twice as wide as the others. Therefore, you cannot reach all switches and controls from the left seat. There is an item in the S-76 Rotorcraft Flight Manual that says:"Minimum crew is one (1) pilot who SHALL be seated in the right seat." My company once had a laminated glass windshield break on the right side. Had to get a waiver with the ferry permit for the pilot to fly it home from the left seat.
 
Why are most boats driven from the right?
 
Why is the left side of the boat called port? (hint - related to the question above)
 
Domenick said:
Why are most boats driven from the right?
Click to expand...
Odd, most boats I've skippered were driven either from the rear or from the center. However, I'm not sure one "drives" a sailboat. Or an outboard with a tiller.
 
Domenick said:
Because that is the side they traditionally put to the pier?
Click to expand...

Yes - back before rudders were a thing, an oar was used to steer a sailboat, and that was normally done on the right and side as it was an easier thing to do on the right as most people are right handed. The terms "Starboard" and "Larboard" were used to described right and left, but "Larboard" was renamed "Port" since that would be the logical side to face the dock.
 
All I know is that "port" and "left" are both four-letter words, and that's how I keep it straight.

It's interesting to hear the history of the "port" term, though.
 
A lot of Cris Craft have the wheel on the port side.
 
Here’s the next boat term question:

Why is the place you steer from called the “bridge”?
 
Bell206 said:
The story I was told through Paul Smith, one of the original Sikorsky R-4 pilots, was that the R-4 only came with one collective so the student pilot sat in the right seat in order to have better control over the cyclic/collective. The R-6 also had a single collective. By the time the Bell 47 and other subsequent models came out, all which had dual collectives, it became more an optional preference where the PIC sat. However, by then you had an entire "1st generation" of helicopter pilots in the US AAC, Navy, CG and UK Royal Air Force/Navy who had only flown from the right seat. So it sort of became the unofficial/preferred side to put the PIC as those original pilots expanded into the rotorcraft field.
Click to expand...

Doesn't the direction of the rotor affect which seat the pilot sits when solo? It seems many helicopters with rotor blades that turn counter-clockwise (when viewed from above) have the PIC on the right, whereas the (French?) helicopters that have rotors spinning clockwise have the pilot on the left. I figured it was due to the physics of asymmetrical lift from the rotor disc and tail rotor compensation. I'm not a physicist or a helicopter pilot so that's all I'll venture to guess.
 
Brad Z said:
Doesn't the direction of the rotor affect which seat the pilot sits when solo?
Click to expand...
No. Never has in my experience. Besides French helicopter blades have always turned in the wrong direction, mon ami. Just ask any Frenchman.:)

PS: the PIC position is determined during certification and to change it requires an STC or OEM bulletin.
 
Bell206 said:
No. Never has in my experience. Besides French helicopter blades have always turned in the wrong direction, mon ami. Just ask any Frenchman.:)

PS: the PIC position is determined during certification and to change it requires an STC or OEM bulletin.
Click to expand...
I didn't mean to suggest that the PIC would change sides based on whether one was solo or not, just that the W&B effect of a solo pilot helped tip the scales to make an engineering determination on which side the pilot should sit on.
 
Brad Z said:
Doesn't the direction of the rotor affect which seat the pilot sits when solo? It seems many helicopters with rotor blades that turn counter-clockwise (when viewed from above) have the PIC on the right, whereas the (French?) helicopters that have rotors spinning clockwise have the pilot on the left. I figured it was due to the physics of asymmetrical lift from the rotor disc and tail rotor compensation. I'm not a physicist or a helicopter pilot so that's all I'll venture to guess.
Click to expand...

It helps with lateral CG with your smaller helos like an R22 but doesn’t make much of a difference for a larger turbine. For instance, the EC130 and Astar both are similar airframes and have rotors that spin “the wrong way.” Single pilot is left in the 130 but right in the Astar.

The reason to offset the seat for CG in a smaller helicopter is due to the skid hanging low at a hover. In a counterclockwise spinning rotor (R22), it produces torque that wants to spin the nose right. To counter that, the pilot applies left pedal. The thrust from the tail rotor wants to move the aircraft right (translating tendency). Pilot compensates by applying left cyclic or in some helos, a control bias that automatically applies left cyclic input to the swash plate. Some (B407) even have a left tilt built into the transmission to help compensate. Also, If the tail rotor thrust vector (right) isn’t inline with the main rotor lateral vector (left) that will even aggravate the condition more. At any rate, all those offsetting control forces will produce a left skid low condition. Having a heavy pilot in the right seat does help slightly with that.
 
Brad Z said:
I didn't mean to suggest that the PIC would change sides based on whether one was solo or not, just that the W&B effect of a solo pilot helped tip the scales to make an engineering determination on which side the pilot should sit on.
Click to expand...
Not to my knowledge and experience. The position of the designated PIC seat is based more on mission/control geometry/engineer preference/etc than W&B. For example, a left seated driver is better for utility work or in some models offers the ability to install a double front pax seat, where a right seat driver is less accomodating.

But the PIC seat designation is simply a certification item and is usually related to instrumentation or control dynamics. Depending on the aircraft and approved data to alter the PIC position, it could be as simple as adding a mag compass or torque gauge to the opposite seat area to as complex as relocating primary flight and engine controls.

Where W&B and solo pilot ops come into play are on those models that have certified minimum cockpit weights like 170lbs in some Bell products. When a pilot is weight challaged in these circumstances they usually carry their own personal weight bag to make the 170 lb limit.
 
Because the collective is on the left and the cyclic is held in the right hand. Most the switches and buttons are in the middle. Helicopter pilots can more easily let go of the collective to make radio switches, etc, than they can the cyclic.

That's how it was 'splained to me.
 
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