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  1. #1
    Lalani Guest

    maintaining altitude and airspeed.

    I've been really bummed out because I'm having a hard time understanding how to maintain a proper altitude and airspeed. It's just a fundamental I haven't been able to get. I brought it up to my CFI and even after we went over it a few times it still hasn't been clicking. I think what the real problem is is that the airplane is just such a horrible classroom! Too many new sensations, too many things that need divided attention, ...

    Any tips or tricks?

  2. #2
    Join Date
    Mar 2003
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    It's hard to tell what's going wrong without seeing what you are doing. But most of the time, it's chasing instruments around along with a failure to learn the visual (looking out the window) cues of what straight and level looks like.

    If that's the case, someone's CFI needs to start covering instruments Single best cure I know of.

  3. #3
    cnthinkoname Guest
    When I started training I had the same problem. I felt so overwhelmed with so much going on at once. Radio (class C) , heading, altitude, coordinated flight, etc. After I few lessons I began to figure it out (it took me around 4-5 lessons). How much time have you been flying?

    Looking outside is CRITICAL. I was relying on instruments, but found that the VSI on the g1000 cockpit lagged a second or so and as a result I was all over the place. I learned where level was in relation to the dash and horizon (changes with airspeed), trimmed to that (you would be surprised as to how much this helps), and made very minute adjustments with 2 fingers to not over control.

    On a somewhat separate note, when you think you are trimmed let go of the controls and see what happens. It turns out when I thought I was trimmed, I was nowhere near close.
    Last edited by cnthinkoname; 09-25-2011 at 18:47.

  4. #4
    Join Date
    Aug 2007
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    Quote Originally Posted by Lalani View Post
    I've been really bummed out because I'm having a hard time understanding how to maintain a proper altitude and airspeed. It's just a fundamental I haven't been able to get. I brought it up to my CFI and even after we went over it a few times it still hasn't been clicking. I think what the real problem is is that the airplane is just such a horrible classroom! Too many new sensations, too many things that need divided attention, ...

    Any tips or tricks?
    Set aside an hour or two and read this, written by a physics professor/CFI and available only online. Concentrate on those sections relating to energy management. www.av8n.com/how/

    Bob Gardner

  5. #5
    Join Date
    Apr 2008
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    Just to clarify, when Mark says "covering instruments", he means literally to cover them over--when I was instructing, and students were having your problem, my dish towel would come out, I'd cover the whole panel, and guess what?????? The airplane would still fly!!! Amazing!!!

    Then the next "trick" is to trim. Trim. TRIM. TRIM!!! If you let go of the yoke and the airplane departs for places unknown, you're not trimming--and you're not piloting. He or she who attempts to fly without trimming is not a pilot; he or she is no more than an interested passenger.

    BTW, if G1000 VSIs are only a second behind, that's about 300% better than a steam gauge VSI, which typically lags by almost exactly 3 seconds. But any time you start chasing needles, whether it's to maintain altitude, to maintain airspeed, or to maintain course, you'll fail.

    So here's the deal, Lalani: Set the pitch of the airplane using the yoke, trim off all of the pressure on the yoke, and see what happens. If the airplane is losing altitude, raise the nose a tiny bit, trim again. Vice versa if it's climbing. Let it sit until you can see what it's doing, then fix it. In the process, learn what the pitch looks like, by outside reference mostly, and it doesn't hurt to check the attitude indicator to see if it agrees.

    A couple of weeks ago, I went up to maintain night currency. Once at cruise, I trimmed and just for the heckuvit, I took my hands off the yoke and put them in my lap. For the next 15 minutes, I didn't touch a thing. By the end of that 15 minute period, I had descended 20 feet.

    Don't fall for the mantra that pitch controls airspeed and throttle controls altitude. It's a combination of both--and trim. If you are flying at 120 knots level and then need to fly at 90 knots level, it will take adjusting both throttle and pitch. Wait until you check out in a much faster airplane, where you need to go from 175 knots down to 90 for the pattern and then to 70 for the final approach! But it's all the same--you reduce the throttle, and as the nose starts to drop, you increase the nose up pitch. When you get the hang of it (which will happen sooner than you realize), it'll be a smooth transition of using both as necessary to accomplish the job, and your altitude won't vary a bit.

    Cary

  6. #6
    tomcat7269 Guest
    Just a quick note about trim. It doesn't take much. It is really easy to over trim. What feels like just a tick on the trim wheel can be alot.

  7. #7
    Join Date
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    Quote Originally Posted by tomcat7269 View Post
    Just a quick note about trim. It doesn't take much. It is really easy to over trim. What feels like just a tick on the trim wheel can be alot.
    Yeah, I found that out on our Cherokee 140. It has the overhead trim handle and it can take as little as a 1/4 turn to correct the trim in level flight.

  8. #8
    Join Date
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    Most people fail to understand the relationship between airspeed and trim.

    You need to trim for level attitude at the airspeed you'll be flying.

    If you get to your cruise altitude, reduce power when you level off and trim before you get to cruise speed, you'll always be fighting a climb when you try to get the plane going faster. You need to lower the nose at the required altitude, accelerate to cruise speed, trim off the control pressure and then reduce power to the cruise setting.

    The lesson where this finally sinks in is usually the first dual cross country. After listening to me say "Accelerate to cruise speed before reducing the throttle" for 10 - 20 hours or so, I figure they are tuning me out, so I don't bother. So the student gets to their cross country altitude, lowers the nose and immediately reduces power. They end up trimming for 80 knots or so, flying around nose up. The conversation goes something like this.

    Me: "What airspeed did you use to plan this trip?"
    Them: "105"
    Me: "What airspeed are you doing right now?"
    Them: "80"
    Me: "Well, you can throw that flight plan in the back seat. All your times will be wrong."
    Them: "Well, if I try to go faster I climb."
    Me: "Gee that's odd. What was the airspeed when you set the trim?"
    Them: "About 80... Oh!"

  9. #9
    Join Date
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    That's exactly why trimming is a frequent thing with most experienced pilots. For instance, on a normal take off to go somewhere, I'll set the trim for the approximate take-off setting.
    • Then as the airplane breaks ground, I'll pitch to the angle I want. So I'll trim.
    • Then the airplane will gain speed for the climb out. So I'll trim.
    • Then I'll reduce take off power to climb power, reducing both the throttle and the propeller rpm. So I'll trim.


    Then, when I start to level off at cruise, there will be several things that will happen, which will affect trim.
    • At my cruise altitude, I'll dropped the nose to the approximate correct pitch (which of course varies some depending on the weight I'm carrying). So I trim.
    • Then as the airplane speeds up, the nose begins to pitch up a little. So I trim. Depending on how slow I my climb speed was, I may trim several times before I reach cruise speed.
    • Then at cruise speed, I'll adjust throttle and propeller--and that affects trim. So I trim.
    • Then I close the cowl flaps, the airplane will speed up a few knots, and it'll want to pitch up. So I trim.


    In cruise flight, there are repetitive needs to trim.
    • Later in the flight, with the fuel burning off, the CG will change slightly. So I trim.
    • If I want (or need) to change altitudes, my airspeed will change. So I trim.


    This will go on until I'm on the ground at my destination. So you can see why trimming is so essential, and frequent. It's simply not a "set it and forget it" proposition, if you're going to be a successful pilot.

    Cary

  10. #10
    Join Date
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    A couple of things to remember:

    1) When you reach altitude, set desired power, and then trim until the horizon looks level and the vsi reads 0 climb or descend.
    2) If you change power, you must re-trim. You TRIM for a particular power setting and airspeed, and if either of those change,
    you must re-trim for level flight
    3) An airplane will vary in it's trim altitude slightly, because of thermals, wind conditions and turbulence. You will see +/- 50-100 feet, but it will all even out. This is OK for VFR flight (unless you're near the ceiling of an airspace you do not want to enter, obviously) In perfectly calm air, you'll often see if pegged at 0 fpm up or down if trimmed correctly.

    A perfect trim comes with experience, but it's not rocket science (or is it???) Just remember these 3 facts and you'll be on your way.

  11. #11
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    In all of this discussion, remember that the trim is not a primary flight control. Set the attitude first with the yoke/stick and then trim off the pressures.

    Also, on a longer flight, you're generally throwing out the equivilant of an 8 year old kid every hour (60 pounds or so of fuel). Remember that the trim will change as the plane gets lighter and CG's move (not much in a Piper or Cessna, but a bunch in a Bonanza and some other planes).

  12. #12
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    That's an important point. You should never use the trim alone to set your attitude.

    "When I was your age I had to trim an airplane by holding a model t spare tire over my head.. in the snow."

  13. #13
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    Quote Originally Posted by yankee161 View Post
    That's an important point. You should never use the trim alone to set your attitude.

    "When I was your age I had to trim an airplane by holding a model t spare tire over my head.. in the snow."
    Um, what are you saying here?

  14. #14
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    He's funnin' us old timers.

    Cary

  15. #15
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    Apr 2011
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    Aw SHUCKS! I was late to the party and didn't get to be the first to tell you to TRIM!

    If there is only ONE word that has been most valuable to me as a student pilot since joining this forum, that word is TRIM. I had learned to fly and the use of trim when I flew 20 years ago. Then after starting almost all over again last Spring, I was having a heck of a time with 180 and 360 turns and Cary told me to TRIM. Then I was having less than desirable approaches and Cary told me to TRIM. I'm a slow learner, but the next time I had trouble with something, the answer was obvious, TRIM.

    Since that time, my instructor FINALLY got around to making me do an approach using nothing but rudders, trim wheel and power setting. That was a great exercise, but I wish he would have done it earlier so I would have been reminded how important and useful that trim wheel really is.

    TRIM!

    Thanks Cary

    Doc


 

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