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hychewright

Air Force C-17 Cargo

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I just noticed last night that a C-17 Cargo AC has a stick rather than a yoke.

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Yup. Because its a FBW aircraft, there is no need for a yoke. Yokes were really intended to give pilots extra leverage when operating the control surfaces of the aircraft. In a FBW, there is no such mechanical link, so no need for it. The real question is why the 777 doesnt also have a stick. I guess commonality and familiarity would be the best answer, but its certainly not necessary. 

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Not that your reason for the original need for the yoke is invalid, but I doubt FBW was the reason to choose a stick over a yoke for that aircraft. The purpose of choosing the stick over a yoke probably has more to do with training, mission requirements, and attitude. The C-17 does a lot of stuff that are 'fighter stuff' like formation flying, evasive maneuvering, low level flying, aerial refueling, and even lands like a fighter. So I would bet the main reason is to help pilots maintain a similar mindset of a fighter pilot to make aggressive, dynamic and precise maneuvers.

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Yup. Because its a FBW aircraft, there is no need for a yoke. Yokes were really intended to give pilots extra leverage when operating the control surfaces of the aircraft. In a FBW, there is no such mechanical link, so no need for it. The real question is why the 777 doesnt also have a stick. I guess commonality and familiarity would be the best answer, but its certainly not necessary. 

 

This makes since Josh.

Not that your reason for the original need for the yoke is invalid, but I doubt FBW was the reason to choose a stick over a yoke for that aircraft. The purpose of choosing the stick over a yoke probably has more to do with training, mission requirements, and attitude. The C-17 does a lot of stuff that are 'fighter stuff' like formation flying, evasive maneuvering, low level flying, aerial refueling, and even lands like a fighter. So I would bet the main reason is to help pilots maintain a similar mindset of a fighter pilot to make aggressive, dynamic and precise maneuvers.

This makes since as well, I saw a tv special on the C-17 and as you stated is was amazed to see how the AC handles as low alt. and fast speed.

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Not that your reason for the original need for the yoke is invalid, but I doubt FBW was the reason to choose a stick over a yoke for that aircraft. The purpose of choosing the stick over a yoke probably has more to do with training, mission requirements, and attitude. The C-17 does a lot of stuff that are 'fighter stuff' like formation flying, evasive maneuvering, low level flying, aerial refueling, and even lands like a fighter. So I would bet the main reason is to help pilots maintain a similar mindset of a fighter pilot to make aggressive, dynamic and precise maneuvers.

 

This is directly from a Boeing engineer:

 

"As the AMST test pilots had requested, the new "electric" STOL airlifter had a stick vice a yoke - although the B-1 bomber was then flying with a stick controllers, making it seem a less radical feature. By that thiem the subject of a sidestick controller for FBW was raised. A center stick was chosen because a the sidestick would not provide the leverage required to fly the aicraft via the C-17's mechanical back-up control system (a mandated safety feature) and because Air Force evaluation pilots universally preferred the centerstick. Only the upper portion of the stick column rotated laterally while the entire column displaced for and aft, ensuring no interference with the pilot's legs. There was an opinion, which went to high levels of the Air Force, that an airplane with a stock ought to be flown with the right hand from either seat and with a separate set of throttles for each. The B-1 bomber was configured as such and this lent weight to the arguments. However, the single set of throttles was a fundamental design feature of the C-17 from the beginning. This was based largely on the need for crew coordination on throttle management during takeoff, as was typical of many military transports and most commercial airliners. Consequently, the single set of throttles mandated a left-handed stick grip for the pilot and right-handed grip for the copilot. Pilots with a fighter background initially found it disconcerting when they first grabbed the pilot stock with their right hand. The logic, derived from the early YC-15 design was that because the pilot in command - in the left seat - operated with a stick, it would be unacceptable that he frequently switch hands on the stick to reach for controls in the overhead or center consoles. On the C-17 the mechanization of joining two sets of throttle and reverser levers so that they moved together, with the hardware going under the pilot seat and up to the center console, was also going to be prohibitively difficult"

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Right, because the usaf pilots universally preferred the center stick. Why? Because these high level fighter guys just wanted to make it feel like a fighter. Fbw makes it possible to discard the yoke, but the decision to do so is to make it feel like a fighter, not for the sake of fbw. The center throttle is also a non issue. Though I had the same reservations approaching it, I never had any actual problem flying from one seat or the other in a stick and center throttle cockpit.

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Right, because the usaf pilots universally preferred the center stick. Why? Because these high level fighter guys just wanted to make it feel like a fighter. Fbw makes it possible to discard the yoke, but the decision to do so is to make it feel like a fighter, not for the sake of fbw. The center throttle is also a non issue. Though I had the same reservations approaching it, I never had any actual problem flying from one seat or the other in a stick and center throttle cockpit.

 

The reason for the stick was made pretty clear here:

"By that thiem the subject of a sidestick controller for FBW was raised"

 

Nothing in his logic or explanation makes any mention of fighter aircraft familiarity or consistency other than the discomfort of using their right hand. It was implemented because of FBW and its placement was made based on the need to access the mechanical backup controls and the cockpit layout. Its initial reason for existence had nothing to do with fighter design. 

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Well, we must not be reading the same article. It seemed pretty clear in the article that the amst pilots wanted a stick to begin with....like a fighter. To which the engineers then proposed a fbw sidestick...like an airbus. To which the usaf countered with a center stick and left throttle......like a freakin' fighter. To which the engineers compromised with a center stick and center throttle. Fbw can work with stick, yoke or ram horns. To say a stick is due to fbw makes no sense since you could as easily have a yoke. It is a stick due to the fighter pilots running the usaf like having sticks in their hands. Fbw merely made it feasible on a that kind of plane. Like you already said, it is about commonality and familiarity.

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Well, we must not be reading the same article. It seemed pretty clear in the article that the atsm pilots wanted a stick to begin with....like a fighter. Which the engineers then proposed a fbw sidestick. To which the usaf countered with a center stick and left throttle......like a fighter. To which the engineers compromised with a center stick and center throttle. Fbw can work with stick, yoke or ram horns. To say a stick is due to fbw makes no sense. It is a stick due to the fighter pilots running the usaf like having sticks in their hands. Fbw merely made it feasible on a that kind of plane.

 

So the Airbus was deigned for fighter pilots?

 

WWII fighter planes with cramped cockpits used sticks vs yokes which were found in larger bombers. The yokes main purposed was to allow leverage against a mechanical system which was more prevalent in the large bombers, if that need is no longer present, a stick becomes the ideal control input as they take up less room in the cockpit and makes for a larger workspace. The AMST pilots were used in research of the aircraft and they were asking for a FBW/Electric STOL cargo aircraft. If the case study from them was biased towards familiarity of the inputs of a fighter plane, then it would have been stated. But what was stated was that with this FBW input, a yoke was no longer needed, so a stick was used and thus the debate about where the stick should be placed began. 

 

One further case to the lack of familiarity being a factor, are the layout of modern fighter aircraft. The F22 and new F35 cockpits both use side sticks, not center sticks. Why? Because the cockpits have been fitted to provide greater visibility to the new, larger, comprehensive displays that are found in these aircraft. 

 

The mission and capability of the aircraft dictates the refinement of the layout. Not the preference of the pilots. 

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So the Airbus was deigned for fighter pilots?

 

WWII fighter planes with cramped cockpits used sticks vs yokes which were found in larger bombers. The yokes main purposed was to allow leverage against a mechanical system which was more prevalent in the large bombers, if that need is no longer present, a stick becomes the ideal control input as they take up less room in the cockpit and makes for a larger workspace. The AMST pilots were used in research of the aircraft and they were asking for a FBW/Electric STOL cargo aircraft. If the case study from them was biased towards familiarity of the inputs of a fighter plane, then it would have been stated. But what was stated was that with this FBW input, a yoke was no longer needed, so a stick was used and thus the debate about where the stick should be placed began.

 

One further case to the lack of familiarity being a factor, are the layout of modern fighter aircraft. The F22 and new F35 cockpits both use side sticks, not center sticks. Why? Because the cockpits have been fitted to provide greater visibility to the new, larger, comprehensive displays that are found in these aircraft.

 

The mission and capability of the aircraft dictates the refinement of the layout. Not the preference of the pilots.

 

Preference of the pilots have as big an importance as any other technical requirements. Ergonomics, cognitive science and human factors are some of the biggest parts of cockpit designs of a modern aircraft. Putting the controls where a pilot expects it is very much part of aircraft design. In the era when the C-17 was designed, a center stick was what fighter pilots of that era was used to. The F-16's right sidestick is now de rigeur since we have had over 30 years of familiarity with that set up now for fighter aircraft. By the way, if you read what I've have been saying with an open mind, you will also understand why a 777 still has a yoke.

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By the way, if you read what I've have been saying with an open mind, you will also understand why a 777 still has a yoke.

 

Aptitude in the commercial airline space is different than that in the military space. As I said before, the mission and purpose of the aircraft dictates military decisions more than cost effectiveness of pilot conversion to different platforms as it does in the commercial space.

 

Regardless, we will agree to disagree. I put forth information from an engineer and you also have your opinion. I will move on to other discussions. 

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Aptitude in the commercial airline space is different than that in the military space. As I said before, the mission and purpose of the aircraft dictates military decisions more than cost effectiveness of pilot conversion to different platforms as it does in the commercial space.

 

Regardless, we will agree to disagree. I put forth information from an engineer and you also have your opinion. I will move on to other discussions.

 

I was almost going to make the comment earlier about you 'speaking like a true engineer'. You gotta look up from your sliderule every so often or else you are going to miss the big picture.

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The F-22 and F-35 both have sidesticks because of what was learned from the F-16.  I remember reading that in the design process one of the reasons the F-16 incorporated a right-sidestick was the ability to have increased controls of the stick in high-g maneuvers. This was carried over to the advanced 5th Generation fighters as they were developed.

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The F-22 and F-35 both have sidesticks because of what was learned from the F-16.  I remember reading that in the design process one of the reasons the F-16 incorporated a right-sidestick was the ability to have increased controls of the stick in high-g maneuvers. This was carried over to the advanced 5th Generation fighters as they were developed.

 

I think I've read something to that effect as well, however it's strange that all the other 4++ and 5th generation fighters, except the Rafale, use a conventional central stick: Typhoon, SU-30, MiG-35, Gripen, PAK FA, etc...

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