Trim is for cruising

[Ed Cesnalis]

Trim is for cruising, and even then you don't want to use it much for short hops unless you are tired and want to tradeoff flying yourself for some relief on the stick and rudder.

 

Until my CTSW is precisely trimmed in all 3 axis it fights me in a most annoying way. I trim a lot and do it without conscious thought, except for the flaperons, they are enough of a pain that I think about it. Of course flaperons rarely need it

 

The stabilator needs trimming quite a lot but I don't trim for turns because the force is light and short lived. I trim rudder for climbs and descents but not for takeoffs. I also trim rudder for fuel management.

 

When trimmed and in good air my CTSW is a pleasure to fly.

 

Set it and forget it vs fight it?

[FlyingMonkey]

Pitch trim should be used all the time, and you shouldn't even have to think much about it. Stick is heavy one way or another, trim it out. I've heard some pilots say they use pitch trim to maintain constant turns. I probably wouldn't do that as it seems more effort than it saves, though for some planes, especially with electric trim, in some tasks it might make sense.

 

Rudder trim...if you are flying and your ball is always out to one side, why not trim it out? It will make the airplane fly better and keep you from fighting the pedals all day.

 

I have not yet had to play with roll trim, but I would use it if I got a wing heavy for some reason not related to fuel imbalance (which is easily fixed flying uncoordinated for a few minutes).

 

Is this even really a debate?

[sandpiper]

 

Is this even really a debate?

 

Shouldn't be

[FredG]

From page 3-7 of the Airplane Flying Handbook (FAA H-8083-3B),

 

"A properly trimmed airplane is an indication of good piloting skills. Any control pressures the pilot feels should be a result of deliberate pilot control input during a planned change in airplane attitude, not a result of pressures being applied by the airplane because the pilot is allowing it to assume control. "

[Ed Cesnalis]

You say 'Precisely' yet you are on a different page. Hand flying an airplane that is out of trim does not give you 'full feel' it simply increases your workload.

 

Trim is a no no? The trim exists, it has to be set somewhere. You are either trimmed for your current attitude or you are not, you can't decide that it is a no no because you are now on approach. And please explain to me why I wouldn't want to trim for my approach speed? The plane doesn't have to be out of trim for me to feel, I just need to have my hand on the stick ( which is a really great idea on approach ) in order to have feel. I much prefer the feel of a trimmed airplane.

[Jim]

 

Is this even really a debate?

 

Sigh.

[Brian]

Decades ago when I took my private flight test the examiner asked why i didn't make more use of trim. We were in a Cessna 150. He then proceeded to demonstrate its benefits by flying an entire pattern using ONLY trim and no elevator. The point stuck and I use trim constantly.

[FlyingMonkey]

Fly ten circuits around the pattern doing touch and go's with no trim changes, then tell me if you need to "alleviate fatigue".

[GravityKnight]

Fly ten circuits around the pattern doing touch and go's with no trim changes, then tell me if you need to "alleviate fatigue".

 

Did 15 yesterday evening, and I was trimming like crazy just to make it easier on myself.

 

It's nice to at least get it in the ballpark during pattern work so you aren't fighting the airplane for no reason....

[FastEddieB]

Decades ago when I took my private flight test the examiner asked why i didn't make more use of trim. We were in a Cessna 150. He then proceeded to demonstrate its benefits by flying an entire pattern using ONLY trim and no elevator. The point stuck and I use trim constantly.

 

Certainly the examiner made his point, and I'm glad you learned from it.

 

An airplane can certainly be flown with the trim. As evidence, that's how many autopilots do it.

 

And proper trimming is a learned skill. Hence, many students underutilize it, as you apparently did.

 

But...

 

There's something called "flying the trim", and it's a habit flight instructors must be on the lookout for.

 

The scenario might be an instrument student who struggles to maintain altitude. First suspect is a poor scan. But the second is the "flying the trim" that I just mentioned.

 

An instructor has to look closely, but let's say the student is nearly 100' high. Instead of decreasing pitch with the stick or yoke, he or she hits nose nown trim. That will return the plane to its desired altitude, but it will be out of trim for level flight and may easily overshoot the desired altitude if the student is distracted. He then sees himself low, and trims more nose up...and so on.

 

The general rule is that the stick or yoke controls pitch, and trim is then used ONLY to relieve pressure, if necessary.

 

Of course, a skilled pilot will use the pitch-feel pressure-trim cycle so quickly it seems almost continuous, and the plane just hugs the correct altitude. Still, "flying the trim" is generally considered a bad habit, and something to look out for.

 

 

[Jim]

Trimming, at least for me, is vital to a good landing. Feeling the same control force and not feeling unneeded control bias force gives me consistent sight pictures and landings. For CTLSi, landing at 60 knots, maybe it's not such an issue.

[GlennM]

Many bigger airplanes can't be flown without proper use of trim. I am dumbfounded. Who is teaching these people?

[Jim]

Many bigger airplanes can't be flown without proper use of trim. I am dumbfounded. Who is teaching these people?

 

I hear it's "one of the more sophisticated schools".

[Ed Cesnalis]

Advocating the use of trim does not mean we are in the wrong airplanes it simply means we have a clue on how to fly.

 

Do you have a link or a source to back up your contention that trim is a no no except for in cruise on long flights?

[FlyingMonkey]

 

 

Bigger airplanes are not the all carbon fiber, high performance FD CTLS....if you want one of those, you are in the wrong airplane.

 

Are there any larger, non-carbon airplanes with higher performance than the CTLS? Do you think they use trim outside of cruise flight?

 

In many aircraft if you do not trim in all phases of flight you literally cannot control the airplane.

 

And once again, there is nothing magical about carbon fiber.

[mocfly]

Andy,

You will learn rather quickly that if you are on a long cross country and you fly with the ball centered the left tank will drain more than the right. I typically fly one half ball out to the left.

 

[sandpiper]

Now I know why my friends RV-12 out runs and out climbs me. It's all those rivet heads out there. Of course, I haven't figured out why his plane glides forever just like a CT.

 

Also, his -12 weighs less than my CT. This is really confusing.

 

But, if not using trim floats your boat, so be it. The rest of us will continue to practice good airmanship.

[FredG]

Andy,

You will learn rather quickly that if you are on a long cross country and you fly with the ball centered the left tank will drain more than the right. I typically fly one half ball out to the left.

 

Chris,

 

My plane used to do this. Then my mechanic found that my Dynon was not installed perfectly (the ball was not centered when the plane was level). After a small adjustment to the level of the Dynon, the tanks now drain equally (ball is now centered when the plane is level).

 

Of course, your plane may be different than mine.

 

Fred

[FredG]

95% of my modest 500 hours of flying and about 98% of my 1800 landings have been in a carbon fiber airplane. I strongly suspect that my regular use of trim has nothing to do with any nearly nonexistent past experience I have with metal and rivets.

[WmInce]

. . . "Bigger airplanes are not the all carbon fiber, high performance FD CTLS....if you want one of those, you are in the wrong airplane." . . .

 

Your assertion there . . . is a little confusing. :wacko:

I don't know what you have previously flown, but just for the record, the "FD CTLS" is not a "high performance" aircraft.

Where in the world did you get that idea?

[WmInce]

. . . "carbon fiber airframes fly more like a glider and less like an old fashioned metal beast .... " . . .

 

Since you have made such a distinction, please tell us . . .

what gliders and "metal beasts" you have flown?

[Craig]

Once again, there is no reason to use trim on landings or at any other time except when you want relief from the controls and are in cruise.

 

http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect

[FlyingMonkey]

LOL Craig.

[Ed Cesnalis]

...Carbon fiber is lighter and has far less drag than metal and rivets. .... its the ESSENCE of why the argument rages over the DIFFERENCE in flight characteristics between old metal craft and the FD.

 

Drag comes from shape it is not a feature of a material, you can build a high drag composite or a low drag design from aluminum. Your statement is not even wrong.

 

There is no such argument raging, what are you talking about, can you supply a link?

 

If you are not willing to supply links or sources for your controversial claims can you say so?

[FlyingMonkey]

Carbon fiber has real disadvantages. It can absorb moisture and lose strength. It loses strength at a far lower temperature than aluminum (aluminum loses 50% of its strength at 400°F...how much strength do you think CF has at that temp? It probably catches fire before that). Carbon fiber is tensile, while aluminum is ductile.

 

Aluminum has a yield strength at which it will bend into a permanent set but not break, which is typically where ultimate limits are set for aircraft. This means that when an aluminum wing reaches its ultimate load limit, it will often bend without breaking. You see this when aircraft land with wrinkled skins and bent spars. But they LAND.

 

When a carbon wing reaches its ultimate limit, the brittle (tensile) carbon SHATTERS. It is done, shredding in a spectacular fashion. Here's an example, the Dreamliner wing destructive test:

 

http://www.youtube.com/watch?v=sA9Kato1CxA

 

After the wing failure, look at the top of the wing, it has broken off in giant flakes. You are not going to be landing that airplane. The CT series has a service limit of 4g positive, so using the FAA 50% rule, we can surmise that the ultimate limit of the wing is about 6g or more, very similar to the limits on a 172 or Cherokee. The difference is when you hit that limit in those airplanes, you have a very good chance of continuing to fly and land. In the CT you are finished, I hope your BRS repack was done by a tech who was not hungover that morning.

 

So is carbon fiber the magic special sauce for all future structures? Ferrari does not think so, and estimates that by switching from CF to aluminum they will DECREASE weight by 15-20% and INCREASE strength:

 

http://www.popularme...errari-says-yes

 

Hell, even FD made an aluminum airplane after years of being the poster child for CF aircraft. Why? Ease of maintenance for flight schools; repairing CF is difficult and expensive. Carbon fiber is an awesome material, both light and strong. But it still obeys the laws of physics and has its own limitations.