trimming the default 737-800

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trimming the default 737-800

Postby DenisH » Sun Dec 12, 2010 9:02 am

After a year of flying smaller single and twin engine aircraft I'm now moving up to the larger jets. The default Boeing 737-800 for starters. However, I find manually keeping trim on this airplane almost impossible. Can it be a bug or is trimming larger aircraft best left to the auto pilot? 
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Re: trimming the default 737-800

Postby olderndirt » Sun Dec 12, 2010 10:39 am

[quote]After a year of flying smaller single and twin engine aircraft I'm now moving up to the larger jets. The default Boeing 737-800 for starters. However, I find manually keeping trim on this airplane almost impossible. Can it be a bug or is trimming larger aircraft best left to the auto pilot?
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Re: trimming the default 737-800

Postby DenisH » Sun Dec 12, 2010 12:16 pm

OLD:  Hand. Can't keep it level with manual trim more than a minute or two. Then it seesaws. 
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Re: trimming the default 737-800

Postby olderndirt » Sun Dec 12, 2010 8:53 pm

[quote]OLD:
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Re: trimming the default 737-800

Postby DenisH » Sun Dec 12, 2010 9:57 pm

Yep!  But still a marvelous hobby for us men of a certain age. . Better than searching for nickles and dimes under now-outlawed playground monkey bars with a metal detector.
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Re: trimming the default 737-800

Postby RitterKreuz » Mon Dec 13, 2010 9:56 am

One thing i would like to add to the discussion is the length of airliners makes the aircraft one big seesaw.

let me provide a real life example.

You constantly have people getting up and going to the lavatory, flight attendants constantly walking up and down the aisle with their service carts etc, even fuel burn - these all change center of gravity constantly, even if only slightly.

with the autopilot on, if you had the opportunity to sit in the flight deck as i have and feel trim wheels against your leg or see them from the jump seat etc - generally they are constantly moving - re-trimming the aircraft - only if a little at a time.

it would be a full time job to hand fly an airplane such as a 737 or 747 etc in cruise flight from point A to point B

generally the practice is to hand fly the aircraft to an initial altitude about 2-3,000 ft above ground and then activate the autopilot which has been pre-set while on the ground to desired variables such as speed, altitude and heading etc.

as changes need to be made to heading or altitude - then the desired altitude or heading is selected and the system takes care of the rest.

for the most part, in the airline environment you are a "systems manager" more than you are an "aviator", with "hand flying" accounting for probably 10-15% of an actual flight.
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Re: trimming the default 737-800

Postby DenisH » Mon Dec 13, 2010 11:14 am

RITTER   Many thanks for your very lucid explanation. Your comment re systems management is interesting and makes me wonder why flying the big jets is so popular in flight simming.
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Re: trimming the default 737-800

Postby reachva » Mon Dec 13, 2010 6:35 pm

as Ritter pointed out, in modern airliners you spend very little time actually flying the plane and more time watching the systems in case of failures. Its well known that modern aircraft could fly themselves completely without the needs for a pilot at all but its not done as passengers wouldn't feel safe trusting their lives to a few computers.

If you want some hands-on flying, the piston pounders are for you ;)
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Re: trimming the default 737-800

Postby DenisH » Mon Dec 13, 2010 10:41 pm

Yep. I wonder how the early jet airliners were flown? Half & half? I flew on a BOAC jet flight years back but can't recall the  aircraft model (if I ever knew it). This was during the time when   prop airliners were being phased out on major routes. I was spooked (as usual) because BOAC's safety record was suspect at the time. Or maybe it was the aircraft's record. I forget which.
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Re: trimming the default 737-800

Postby Hagar » Tue Dec 14, 2010 2:53 am

[quote]Yep. I wonder how the early jet airliners were flown? Half & half? I flew on a BOAC jet flight years back but can't recall the
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Re: trimming the default 737-800

Postby DenisH » Tue Dec 14, 2010 10:26 am

Hagar: Yes, you're correct. It was the Comet.
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Re: trimming the default 737-800

Postby olderndirt » Tue Dec 14, 2010 10:32 am

Even with the smallest personal aircraft, you can spend a fair amount of time adjusting trim tabs so that, in smooth air, that baby will fly hands off.
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