Rudder Trimming

Rudder Trimming

Rudder Trimming

There is a certain order to trimming a plane and that can vary a little from pilot to pilot. Most pilots will concentrate on the elevator trimming first to keep the plane flying a level path. This is especially important if the plane wants to dive, then elevator trimming becomes the primary important trim for the pilot. In most cases you will be trimming the ailerons along with the elevator to keep the wings level. Once both these control surfaces are trimmed to a comfortable standard you can begin trimming out the rudder.

Now some pilots will not even bother going past the elevator/aileron trimming step, and never bother to trim the rudder at all. But it is very important to trim out the rudder for nice straight and level flight. Rudder trimming starts by performing figure eights in the sky and watching to see how the plane reacts. If you are making a left turn and the plane wants to climb during that turn you will need to add left rudder. If the plane wants to dive then you will have to add right rudder. Now when you are turning the plane to the right if the plane wants to climb you will have to add in right rudder, likewise if it tends to dive trim in left rudder. Continue flying the figure-8’s until your plane performs nice smooth turns through the right and left banking.

Keep in mind that throughout this whole process you will most likely have to add in small increments of both elevator and aileron trim. Generally when you are trimming out one control surface it will affect the others. So just take your time and realize that trimming out a plane can be an ongoing project. This can be especially true if your first flight is on somewhat of a windy day. Always take wind into consideration when trimming your plane that is not to say you shouldn’t trim out your airplane on a windy day.  But just understand that it may need some slight tweaks the next time you fly on a calm day.

Try trimming out your planes following these suggestions and I am sure that you will find your plane flying a little better. A properly trimmed out plane is always fun to fly and is always worth the time invested to get it right. Enjoy.

Rudder Trimming

 

 

 

 

Updated: January 26, 2017 — 1:57 PM

21 Comments

  1. This is a great little article. Nice, concise tips. Trimming the rudder is something I need to get better at myself, so this was helpful. Thanks!

    ~Gabriel
    http://electricrcaircraftguy.blogspot.com/

    1. Might have been worth mentioning how to check for correct motor angle and also to adjust linkages annd centre Tx trims post trimming the plane

  2. Complete waste of time reading this article. One of the reasons I stopped taking MAN was that most of the authors seem to have little to no experience. I have no interest in watching the blind lead the blind.

  3. Are you talking about a fixed trim adjustment or a mix?

  4. The easiest way to trim rudder is to do a level wing loop and see if the plane works in the vertical axis of the loop. If you find the plane falling off to one side to the other, trim it out with the rudder.

  5. In full scale, (I now a lot of people don’t want to hear this), you make coordinated turns, ball in the center. I the pilot does not, the plane will not stall wings level straight ahead, or to wings level out of a stall done in a turn. If U are unfamiliar with this concept, just think of a carpenters level on the dash, instrument panel, placed level on the ground before flight. What the ball indicates is if skidding to the outside or slipping to the inside of the turn is taking place. What does this mean to R/C pilots? Planes are meant to fly most efficiently, and comfortable to the passengers, that is, not being tossed around in the cabin because of sloppy uncoordinated turns. Our day will come when we can see the ball, (turn coordinator) in our R/C planes. All U would need is a cockpit camera and a read out deviece. So, first, the plane is not flying as efficiently as possible if not coordinated in turns and, in the extreme, enough right rudder in a left turn in a Cessna 172 or Cub type airplane will cause a snap and spin if held fully in place to the opposite direction. I ruder trim my R/C planes at idle power at altitude, (three mistakes high), by applying increasing up elevator pressure slowly with no other control input until I observe a clean breaking stall. I then observe which if any wing dropped and make a slight trim correction before trying it again until I get to a clean no wing drop stall. Left wing drip, add right rudder. It may not be perfect, but it is always close and helps prevent the old (wing tip stall) on landing. I also trim for vertical line if needed in Top Hat or similar maneuvers. wallace.tharp

    1. Very accurate info on reversing the rudder from the direction of the turn. I’ve done it many times on purpose, back when I was flying Cessnas. 150s really snap. The first time I tried it, it scared the heck out of me.

  6. Thanks for this tip.!

  7. This is some good info. but it completely leaves out trimming the engine. Without the right thrust, the elevator and rudder can end up way out of whack to keep the plane straight.

    1. You’re absolutely correct. Use the example of a Cessna 172. The factory set it up so that at recommended cruise R p.m., that would be cruise speed also. Everything is set so the airplane goes right straight ahead with no control input. Believe it or not go look at the Cessna manuals if you’re doubting, no control surface on a 172 is 00 everything has a slight tweak to it so that in fact taking in account four forces of flight, try not to PhD it here, The airplane should be right straightahead hands off with nothing but elevator trim used to hold altitude. Many full-scale airplanes have a little bendable tabs on an aileron, rudder and elevator to help with this. Hope this helps. The guys right if you don’t have down thrust and general a little bit of side thrust to compensate for what’s going on with a spinning propeller it will climb or dive with added power power which is not desirable.

  8. Usually i trim the rudder in another manner: I take the airplane in a vertical climb, then i see if it goes straight, or goes a little bit on the right or on the left. Obviously if it, for example, goes on the right, then i trim the rudder on the left.

  9. I really enjoyed your article. After being a full scale flight instructor for over 20 years I took up building and flying RC airplanes four years ago. I find it very difficult getting my head in the cockpit and performing coordinated maneuvers in my RC planes. My rudder inputs are very lazy but I am working on them.

  10. Great tips, trimming the rudder isn´t the thing most pikots do careful enough. Today most new pilots are learning to fly with ailerons and elevator, i found most of them don´t knowing what the rudder is for. For me, the rudder is more important than the ailerons for flying curves. I fully agree with Wallace Tharp, nice comment! My plane models do loops without doing silly things, they fly just as i want.

  11. Simplicity in presenting is your main feature …so… Thanks indeed and all the best

  12. Not a one mentioned the wind speed and direction. The one thing that affects the rudder the most.

  13. Ok so here’s a observation from an experienced pilot that a Newby pilot might need some clarification on. The figure 8s you are doing, are we using aileron and Elevator to accomplish this, you need to give full details on how to do the figure 8s.

  14. I agree with “sky king” mostly. I trim my rudder doing “wing-level” vertical loops, CONTINOUSLY!! If the plane “cork-screws” one way or the other, then you add in some opposite rudder trim, until the aircraft “appears to be on a rail” and doing constant loops on the same “rail”.

  15. Trim!, many approaches and here is another to determine rudder trim and CG at the same time. Set cruise power, trim ail. and elevator for level flight, then add full power, climb to highest altitude, throttle to cruise. NOW, fly straight down and let your sticks go. If the nose rises your plane is nose heavy, if it tucks under, you are tail heavy. The rudder trim if not correct will yaw the nose left or right if not correct.

  16. Well written article but I had a couple of questions about rudder trimming that I asked one our club members, a very accomplished pattern flyer. His answer is posted on facebook at the following link.

    https://www.facebook.com/groups/382740478473157/permalink/918228131591053/?comment_id=918234134923786&reply_comment_id=919303808150152&notif_t=group_comment_reply

  17. This appears to be more for setting up an aileron to rudder mix than for actual rudder trimming.

  18. I’m a beginner and your tip is a good one, thanks

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