I agree. trim is mainly for rigging problems, fuel imbalance and s=assymetrical thrust to synch engine rpm but never for in flight winds because once in the flow you need none. Only after take off or before landing do you need to do much with an airline rudder in the air. The yaw damper takes care of turns, etc. Be careful when you go back to the J3. The best way to trim a jet is synch the engines and use the rudder trim to make the wings level. One captain I had put our inclinometer ball in the middle and flew in a slip so I got a screwdriver and leveled the inclinometer to make him fly straight. We saved fuel and drinks were not sliding off the table. I thought everybody knew that.

How exactly did you 'level the inclinometer with a screwdriver ?

I put a small screwdriver in my flight bag so when my captain insisted on flying with one wing up with the ball centered on the 737 200 when we were level on the ramp I used the screwdriver to put his ball in the middle and it worked every time. The inclinometer in the 737 200 had a screw on each side to level it. He was always out of the cockpit of course when I did it. I just wanted our airplane to fly level as it should be flown.

I thought if the ball was in the middle that means you are NOT slipping? (providing slip indicator is accurately adjusted) "when we were level on the ramp I used the screwdriver to put his ball in the middle" As it should have been anyway. No?

Awesome Bubbers. Haven't you heard of talking?

Also you understand what a Tech Log is? And engineers?

It's actually less complicated than that.

Remember the Boeing factory is one of the largest (certainly one of the longest) buildings in the world. It was built before the days of laser surveys and as a result has a very slight curve built into it. Due to the direction of the production line, this manifests itself in microscopically curved aircraft hence the need for trim.









I just wish I'd thought of this a few days ago. :}

bubbers is right about P factor...climb...right rudder, cruise nothing, left rudder in descent (9f any).

now, I think the planes, all planes are a bit twisted, so trim it out and good luck.

but if you do ask yourself this question...which side of the plane do you start first? which tank provides fuel to the apu?

Rudder Trims....
 

We had a fleet of 23 737-200s and all except one, required right rudder trim in climb, some in cruise and none in descent. We had a close relationship with the engineering guys and the rigging department was sure that the trims were set to neutral.

We are taught to believe that there is no torque on jet engines, but considering this discussion isn't a 'one off', maybe there is some credibility in it. We used to toss this one around over a coffee and in the bar a lot and we all felt that considering the amount of power/weight generated, torque did have an influence.

I really doubt a 200lb lateral imbalance is going to be noticed on a 160,000lb 737-800.

I like bubbers' solution. Sometimes that is the most expeditious.

So many aircraft in the fleet have balls not leveled properly that I have relegated to using the ball for an engine-out and the heading for rudder trim. I have only worked one place where MX has leveled the slip/skid indicator properly on both sides.

Only use the ball if you can confirm center with wings level (autopilot off) and no heading change. Nice to recheck trim as fuel burns off on a long flight.

Pilots'level decreasing quickly, they will soon have to navigate like Old Vikings going to America : maintaining constant latitude by keeping constant height of the star Polaris watched on the Starboard (of course)! Right trim gives Givry correction to stay on loxodromic course...

and specially april 1.:p

I know leveling the inclinometer is not the copilots job but it made my captain fly wings level again. I used the attitude indicator to make the wings level on heading when I was captain but FO's can only help the captain so much when they have their technique of ball in middle so fixed it. The captain would never let me make a maintenance call to fix a crooked inclinometer so I did. That is what a good FO does, right?

Right! Ability to survive is the first skill of a pilot.
Surviving needs not survive but live ;)

An unlevel inclinometer is safe just not efficient if the other pilot insists on using it to trim if it is not adjusted properly. Holding a constant heading with one wing down I am sure makes no sense to anybody but some of my captains back then were taught that way. A glass of water on a level surface would do the same thing. A low wing requires opposite rudder so more drag and more fuel burn.

Remember a long time ago when we all knew how to do a forward slip and if we were high slip off altitude with no speed change with the drag and the side slip for a crosswind which was basically the same thing but reference was a bit different? Training was different then but aerodynamics remains the same, right aileron,left rudder and more drag. It sucks in cruise though.

e never new that . and flew RR and Prat (they turned differen directions , although the P n W.was only on a short lease

They could fix the problem by putting a RR engine on one wing and a GE/PW on the other wing.

Naw, that'd just cause a new problem as that silly arsed, backwards turning, three-spooled, RR mongrel motor turns so much fuel into smoke on start-up there'd be perpetual fuel imbalances. :p

There's always a 'work around'. They could add oil to the exhaust of the GE/PW so that it smoked too.

[QUOTE] Is it the same for different engine types?
Rollers turn one way, GE/PW the other.
I would expect diferent trim for different engines if it was linked.
Just a thought.
/QUOTE]

We have both Roller and GE's on our 777's and they both required RIGHT rudder trim.