Mastropiero From Spain, joined Dec 2005, 90 posts, RR: 0 Posted (12 months 3 days ago) and read 3626 times:
Hi everyone!
I recently came across a cockpit shot of a De Havilland DHC-6 Twin Otter and it got me wondering. Is it really comfortable for the pilot to have the throttles on the overhead panel? You can see it in these pictures:
Now, I am not a pilot but from what I´ve read about flying, usually the pilot will fly a good deal of time with one hand on the stick/yoke and the other on the throttles - I´m talking about finals -. It hardly seems the ideal arrangement for me, as even just keeping your hand above your head puts some strain on your shoulder. It´s no big deal when you´re on the bus and have to grab a handle, but is it comfortable for something as precise as operating the throttle levers?
Also, what other aircraft have overhead throttle levers?
Avt007 From Canada, joined Jul 2000, 2094 posts, RR: 7 Reply 1, posted (12 months 2 days 21 hours ago) and read 3554 times:
I can tell you from a maintenance point of view, it's very uncomfortable when you bash your head on them! . You also hope your fellow pilots have been good about taking showers and using deodorant.
VTBDflyer From Thailand, joined Aug 2006, 341 posts, RR: 0 Reply 2, posted (12 months 2 days 17 hours ago) and read 3460 times:
What about getting a tingling feeling in your arm after a while. For example, when you have your hand up over your head for a while, it feels like all of the blood has drained out of your arm, which for me, limits my ability to move my arm or hand with any precision. Just wondering if this would be a problem to a pilot in a case like this.
B6JFKH81 From United States of America, joined Mar 2006, 1207 posts, RR: 2 Reply 3, posted (12 months 2 days 17 hours ago) and read 3448 times:
What was the reasoning for putting the throttle controls up there? High-wing with engines above the fuselage, so to run throttle cables they did the controls on the o/h panel?
"If you do not learn from history, you are doomed to repeat it"
Mastropiero From Spain, joined Dec 2005, 90 posts, RR: 0 Reply 4, posted (12 months 2 days 15 hours ago) and read 3408 times:
Quoting VTBDflyer (Reply 2): What about getting a tingling feeling in your arm after a while. For example, when you have your hand up over your head for a while, it feels like all of the blood has drained out of your arm, which for me, limits my ability to move my arm or hand with any precision. Just wondering if this would be a problem to a pilot in a case like this.
My point exactly!!!
Thanks for putting it so much better into words than I did.
Starlionblue From Greenland, joined Feb 2004, 13702 posts, RR: 67 Reply 5, posted (12 months 2 days 14 hours ago) and read 3390 times:
Quoting VTBDflyer (Reply 2): What about getting a tingling feeling in your arm after a while. For example, when you have your hand up over your head for a while, it feels like all of the blood has drained out of your arm, which for me, limits my ability to move my arm or hand with any precision. Just wondering if this would be a problem to a pilot in a case like this.
As I understand it, apart from during approach and landing (and some emergencies), the throttles aren't really moved that much. It's "set power", then nothing for a while. So the pilot flying wouldn't be hanging on the the emergency brake (hey that's what it looks like) for terribly extended periods.
Just a theory.
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KELPkid From United States of America, joined Nov 2005, 4407 posts, RR: 8 Reply 6, posted (12 months 2 days 14 hours ago) and read 3376 times:
Quoting Starlionblue (Reply 5): As I understand it, apart from during approach and landing (and some emergencies), the throttles aren't really moved that much. It's "set power", then nothing for a while. So the pilot flying wouldn't be hanging on the the emergency brake (hey that's what it looks like) for terribly extended periods.
Just a theory.
I don't know, my flight instructors all taught me that one hand never leaves the throttle(s) during the takeoff, climbout, or approach phases of a flight...I'm sure once you become a pro, stuff like that might become a little more relaxed
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
LimaFoxTango From Antigua and Barbuda, joined Jun 2004, 349 posts, RR: 1 Reply 9, posted (12 months 2 days 2 hours ago) and read 3178 times:
I have a number of friends who flew the Twin Otter and from what I gather, it's more comfortable than you think. Never had I heard anyone complain about its position. I guess its like one of those " Boeing yoke to Airbus sidestick" arguments. Probably only takes one flight to get accustomed to it.
You are said to be a good pilot when your take-off's equal your landings.
Mastropiero From Spain, joined Dec 2005, 90 posts, RR: 0 Reply 12, posted (12 months 1 day 17 hours ago) and read 2986 times:
Quoting LimaFoxTango (Reply 9): I guess its like one of those " Boeing yoke to Airbus sidestick" arguments. Probably only takes one flight to get accustomed to it.
You have a point there, although for me it looks like a different situation. Again, I am no pilot so I am only judging this from a very basic perspective. In the yoke vs sidestick, your arms/arm are always in a relaxed position regarding your body. Operating a lever above your head is not a relaxed position. Can you get used to it? Certainly, that´s not the point. I still think it just doesn´t look right.
Pihero From France, joined Jan 2005, 1890 posts, RR: 62 Reply 14, posted (12 months 1 day 14 hours ago) and read 2952 times:
Quoting Starlionblue (Reply 5): As I understand it, apart from during approach and landing (and some emergencies), the throttles aren't really moved that much. It's "set power", then nothing for a while.
Having flown the Twotter quite extensively, on a single pilot ops, I can vouch for its total lack of comfort...on the ground.
It's quite OK in flight, but taxying that beast is an absolute nightmare : Remember, you need a ground pitch, called here the "Beta mode" and Beta is achieved through a motorbike-throttle type of arrangement, i.e use your wrist... Now, the airplane, because of it's very lifty wing and its narrow wheel base is awfully sensitive to crosswind... Now you have a problem because you need to steer the thing ----> use the tiller : that's the lever you can see behind the left wheel, but at the same time, you will need to keep the aileron into the wind with the yoke (hint, use your legs !) and taking advantage of the serrated surfaces of the throttles, keep the props in beta ! And if you need some braking ? use the foot pedals...and you could find yourself in a bind.
That thing was designed for monkeys or two pilots. (which probably proves that two pilots are equal to a monkey ).
Another thing, off topic : DC-3 style, there is no gate for the flap positions.
Dymondjack From United States of America, joined Feb 2009, 18 posts, RR: 0 Reply 16, posted (11 months 4 weeks 22 hours ago) and read 2682 times:
I've never flown using an overhead throttle control, and I think I would prefer not to. Aside from mentions already made about losing some sensitivity if your arm is raised for a period of time, I think you'll experience less control using an overhead throttle.
Consider what muscles are used when using either type of throttle control: In a standard setup, you arm is generally parallel to your lap, allowing the motion to be controlled more through the muscles in your shoulder, and less with the muscles in your elbow/forearm. Your elbow and forearm are more or less stationary and the muscles used there are basically a backup.
With an overhead throttle, that all changes. While some of the motions can still be utilized by the muscles in your shoulder, you now need to pivot around your elbow as well (abliet only slightly), and even moreso, you rely on the muscles in your forearm for accuracy in positioning the lever. And your wrist, come to think of it. I think this is more noticable in the second picture (w/ the white uniform). His arm is raised, and the motions of applying throttle in either direction are heavily reliant upon using muscles in the wrist and elbow. Especially when trying to pull the throttle back just a c-hair... I could easily see it 'skipping' - being very difficult to pull back just a bit, with a good chance for it to jump back suddenly, going further than desired.
In the first picture (with the uniform jacket), his shoulder seems to be a bit higher, whould would allow for more of the force required to come from there, but is still dependant on holding the wrist and elbow steady at an angle from the direction of force applied. I would think, given that scenario, one might be able to rotate his shoulders some to rely less on having to use the wrist/forearm/elbow, but that would certainly make it more difficult to manuver rudder operations, which wouldn't be desirable in moderate crosswinds.
To sum it up, put your fist in front of you, parallel with your lap if your sitting, and use your other hand to push back against it. There is little stress against the wrist, forearm, and elbow, and is mostly controlled by the bicep/shoulder muscles. Now, hold your arm up at 45° from that position, and take your other hand and push against it, in the same direction that you did before. This time it's a lot more in the wrist to withstand the pressure. Put your arm up at 60 or even 85° and its even more apparent.
Granted, the backforce of throttle pressure is likely a lot less than my little experiment here, I think it would certainly be a lot more difficult to obtain the accuracy and sensitivity in throttle positioning than it would be with the control in the more usual position, and I would think that most pilots would prefer to have to worry about that as little as possible on an approach... especially in tricky approach situations.
So far my own flight experience consists of an intro flight in a C-172 that I took yesterday (I've got a whole half-hour under my belt now!!), but, while an overhead throttle is mostly likely not a huge deal (maybe even miniscule, obviously I'm not very experienced here), I would personally prefer to avoid them if possible.
Hopefully my attempts at descriptions of the muscles used and forces involved in each scenario are somewhat comprehendable.
"First, get your information. Then you can distort it at your lesiure." - Mark Twain
Jetlagged From United Kingdom, joined Jan 2005, 2087 posts, RR: 14 Reply 17, posted (11 months 4 weeks 19 hours ago) and read 2631 times:
Quoting B6JFKH81 (Reply 3): What was the reasoning for putting the throttle controls up there? High-wing with engines above the fuselage, so to run throttle cables they did the controls on the o/h panel?
You've answered your own question. It's the easiest way to run the cables. Helicopters have engine controls on the overhead for similar reasons.
Some high wing aircraft have conventionally placed engine controls, so I suspect design tradition plays a part too.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
B6JFKH81 From United States of America, joined Mar 2006, 1207 posts, RR: 2 Reply 19, posted (11 months 3 weeks 6 days 23 hours ago) and read 2496 times:
Quoting Jetlagged (Reply 17): You've answered your own question. It's the easiest way to run the cables. Helicopters have engine controls on the overhead for similar reasons.
Cool, thanks for the info! I didn't know that helicopters had o/h engine controls. I gues the old saying is true...you DO learn something new everyday LOL!
~H81
"If you do not learn from history, you are doomed to repeat it"
CTRL_ALT_DEL From Ireland, joined Feb 2001, 60 posts, RR: 0 Reply 21, posted (11 months 3 weeks 5 days 4 hours ago) and read 2258 times:
Another reason why the throttle quadrant is mounted there is because both control yokes are connected to a common center support (see the photo attached by Pihero) which houses and conduits the control cables to the center of the aircraft.
The reverse pitch is selected by rotating the cylinders on the throttle levers to release the levers past idle.
Anyone know why on the floats version of the Twotter the auto-feather is disabled? At least this is the case for the Maldivian Air Taxi examples.
WrenchBender From Afghanistan, joined Feb 2004, 1594 posts, RR: 10 Reply 22, posted (11 months 3 weeks 4 days 14 hours ago) and read 2174 times:
Quoting CTRL_ALT_DEL (Reply 21): Anyone know why on the floats version of the Twotter the auto-feather is disabled? At least this is the case for the Maldivian Air Taxi examples.
Are you sure the 'Auto Feather' is disabled and not the 'Thrust Latches' enabled.
Floats have no brakes, so on start up you do not want the prop blades to have any setting other than zero pitch. hence the latches are installed for float ops.
KELPkid From United States of America, joined Nov 2005, 4407 posts, RR: 8 Reply 24, posted (11 months 3 weeks 4 days ago) and read 2083 times:
Quoting Jush (Reply 23): I really think this could get uncomfortable after a while but I have to admit it does look cool though.
Yeah, in the same way the Millenium Falcon or a 1962 VW Microbus looks cool...
I hear flying DeHavilland Canada products around grows hair on one's chest Personally, I'd love to have 1.5 hours logged in a Beaver just to see what it's like...
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
2H4 From United States of America, joined Oct 2004, 8277 posts, RR: 64 Reply 25, posted (11 months 3 weeks 3 days 23 hours ago) and read 2074 times:
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Quoting CTRL_ALT_DEL (Reply 21):
Anyone know why on the floats version of the Twotter the auto-feather is disabled? At least this is the case for the Maldivian Air Taxi examples.
I assume auto-feather systems require some level of inspections and maintenance. Perhaps Maldivian disabled them to reduce maintenance costs.
I mean, considering they operate from floats on the ocean, do they really even need the system? In the event of an engine failure during or shortly after takeoff, I assume they have the (enviable) option of simply reducing throttle on both engines and landing straight ahead. I suspect, in their case, it's nowhere near as critical to instantly feather the bad prop, clean up the airframe, and claw for altitude to clear obstacles.
KELPkid From United States of America, joined Nov 2005, 4407 posts, RR: 8 Reply 26, posted (11 months 3 weeks 3 days 22 hours ago) and read 2085 times:
Quoting 2H4 (Reply 25): I mean, considering they operate from floats on the ocean, do they really even need the system? In the event of an engine failure during or shortly after takeoff, I assume they have the (enviable) option of simply reducing throttle on both engines and landing straight ahead. I suspect, in their case, it's nowhere near as critical to instantly feather the bad prop, clean up the airframe, and claw for altitude to clear obstacles.
2H4
Definitely not the case for the Twotters on floats I've seen operating out of Victoria Harbor in Victoria, BC...they'd have to go around on one engine
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
Jush From Germany, joined Apr 2005, 1619 posts, RR: 5 Reply 27, posted (11 months 3 weeks 3 days 9 hours ago) and read 2003 times:
Quoting KELPkid (Reply 24): I hear flying DeHavilland Canada products around grows hair on one's chest Wink Personally, I'd love to have 1.5 hours logged in a Beaver just to see what it's like...
:D ... I hope you'll get that growing hair under control. At 6'4" I think logging 1.5 hours in that product gets you back injury
Regds
jush
There is one problem with airbus. Though their products are engineering marvels they lack passion, completely.
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