kidicarus5897

I'm bored. Anyone know what the average tail-down force the horizontal stabilizer produces in cruise flight is? I say average because it varies with CG loading and speed. Or, I guess more specifically, how much does the down force change with a forward versus and aft CG in cruise flight?

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RBower

yep this is definitely a Riddle question



The airplane was built very nose heavy though, its a big 8 up 95% of the time, kind of inefficient. I wonder how much gas that costs over the life of the plane

MKFlying7

It's 8 up for takeoff the majority of the time, but in flight it's significantly lower...0-4 from what I can recall seeing.

8 up on the takeoff roll doesn't burn, but what...maybe a half a pound of gas...ouch

kidicarus5897

anyone know what a a trim unit equals in degrees?

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RBower

No $hit ....What I meant was obviously the cg is farther back if the takeoff trim is 6 instead of 8 , which does affect fuel burn in cruise no matter what the cruise trim is.

Now you'll probably explain to me how ZFW does not matter since we never fly without fuel

Mitch

Now, I am more than likely wrong...

...but isn't our high trim setting on takeoff primarily to overcome the nose low angle of incidence on the wings as we roll down the runway?

In cruise, as has been said, the trim is usually 0-2. So it sounds fairly efficient to me.

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kidicarus5897

I thought the trim setting was so that if we were to pop an engine at V1, the aircraft would already be trimmed for V2........

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Hey, it's not lying if what I said would be true if the facts were different......

RBower

Everybody just forget about the takeoff trim! The point is a lower takeoff trim will equate to a lower cruise trim, meaning less fuel...PERIOD!

A trim of 0.7 in cruise is more efficient than a trim of 1.1 and will equate to small amount of gas, which adds up after thousands of hours. You just cant see the resolution since the trim is in whole units. The Concord had a tail tank that they transferred fuel to to move the cg back and increase efficiency.

D-Luv

8 is lower than 9... Just because 8 is the highest of the allowable take-off trim numbers doesn't mean it's high for the airplane. We really don't know. Also, where is it in the 8 region? The 8 is more than 1/2 the wheel, the 7 is another half, and the 6 is barley in there.

Tacts

Nigel: ...the numbers all go to eleven. Look...right across the board.
Marty: Ahh...oh, I see....
Nigel: Eleven...eleven...eleven....
Marty: ...and most of these amps go up to ten....
Nigel: Exactly.
Marty: Does that mean it's...louder? Is it any louder?
Nigel: Well, it's one louder, isn't it? It's not ten. You see,
most...most blokes, you know, will be playing at ten. You're on ten
here...all the way up...all the way up....
Marty: Yeah....
Nigel: ...all the way up. You're on ten on your guitar...where can you go
from there? Where?
Marty: I don't know....
Nigel: Nowhere. Exactly. What we do is if we need that extra...push over
the cliff...you know what we do?
Marty: Put it up to eleven.
Nigel: Eleven. Exactly. One louder.
Marty: Why don't you just make ten louder and make ten be the top...
number...and make that a little louder?
Nigel: ...these go to eleven.