Help with Trimming

[Zoltar]

Hi Guys,

 

This forum is amazing.:thumbup: Encouraged by the replies i got from you guys for my landing issue, i have decided to get all my problems fixed with the help of you guys. I hope you will not let me down Here is my issue with trimming.

 

1. I take off with a pitch attitude of say 10 deg climb to desire altitude by holding the stick back. So far so good.

2. I slowly bring the stick back to neutral and the FPM is now at 0-------0 line, but momentarily.

3. FPM starts dipping downwards, perfect for trimming a/c for upward pitch. I trim the a/c with couple of tabs on the button for trimming on my stick. FPM starts climbing to words 0 deg. line I am happy.

4. Problem starts when FPM doesn't stop at 0 deg, it keeps on climbing. I trim a/c down and now i am in scenario # 3 :huh: :mad: Aircraft keeps wobbling like this.

5. Things get more nastry if i try to controll the pitch with stick after the above steps.

 

I use logitech attack 3 joystick. I have download the profile provided by logitech for this stick for lock on and use it. Please help.

 

Regards.

[Zoltar]

Hi,

 

I am working with A-10 right now. I have gone through the navigation and landing video for the same. Also to best of my knowledge i havn't seen any procedure for trimming in the manual. But then i am bad at reading manuals. If you can point out where the procedure is given please let me know i will go through it.

 

thanks.

[Zoltar]

I forgot to mention that I have set a little dead zone for pitch axis, with no shift and 50% curve. And when i test the pitch, the "+" and the "." never coincide. Always there is a small not matter how much, but delta between the two signs in the test panel for axes. Does this has to do anything with trimming issue? I am just curious.

[ARM505]

To trim (any aircraft I have flown, without FCS trim, or 'flightpath stability' kind of trim), quick and dirty:

 

1) Use stick to hold aircraft in correct flight attitude for phase of flight (climb, descent, cruise, whatever) - don't worry if you get the attitude wrong, you can adjust it, and you will get better at judging it with experience.

2) Check parameters stable (airspeed, vertical speed etc), or close enough to stable (ie not making rapid changes). The important thing is to hold the pitch/roll attitude.

3) You'll no doubt be having to apply pressure to the stick to hold the aircraft in that attitude - NOW USE TRIM. Trim using small measured changes, and allow time to check the effect. You should be able to take your hand off the stick, and the attitude should not change appreciably. Practice this with wings level, because trimming the rudder/ailerons for steady state turns is a bit unecessary.

4) Monitor airspeed etc and readjust aircraft attitude, then retrim. Again, hold the attitude as accurately as possible, THEN trim for hands off flight. Try to AVOID the common mistake, which is when people end up trying to actually fly the aircraft with the trim, ie make pitch changes with the trim and not the stick.

 

Examples:

A climb - from steady state level flight, raise the nose to what you imagine is the climb attitude, and set climb thrust. Hold the aircraft in your selected attitude, allow parameters to stabilise (You could judge the correct thrust/pitch attitude such that the airspeed does not change for example). Apply trim to hold this attitude, so that even with your hand off the stick it stays there. Monitor, and adjust.

 

Levelling off from a climb: Approaching the planned level off altitude (how much before depends on vertical speed, power, airspeed, etc, use experience as you get better as a guide), lower the nose attitude smoothly (to maintain the target altitude) to obtain the desired level flight attitude. Set cruise thrust (again, just judge it, experience will help). Allow airspeed to stabilise. Hold attitude and trim so that you are no longer required to hold the stick to maintain the attitude. Monitor and adjust attitude to maintain altitude. Hold the new attitude and retrim.

 

Thats the basics, more or less. Experience will show you the correct settings, and of course you can start applying small amounts of trim sooner whilst changing attitude to help you. Remember, don't fly the plane with the trim, just use it to reduce your workload (ie stick forces), thats what it's there for.

 

Pitch trim in simulators is a tricky thing - IRL it's a little smoother and easier, the aircraft tends to settle nicely into a steady state a little more naturally.

[3Sqn_Sven]

Yeah that's exactly how you do it, SELECT the attitude, HOLD it, TRIM it, observe, if it was wrong then RESELT the required attitude, hold, trim.

 

IIRC the A-10 has auto-trim though?

[S77th-konkussion]

Nope- F15 has the auto trim.

[Zoltar]

I got it !!!!

 

Thanks a lot guys. With the help of your valuable advice and a weekend full of trimming :joystick: I finally got it. Now i fly almost level at any speed and altitude.

 

Thanks again and I will soon posting some more problems. :D

[dynamocl]

Currently at work at the moment. I have the trim set to a rotary control on my HOTAS. But for those who don't have rotary and other axis controls available, can they use the mouse wheel to control trim? May be a little better than using the keyboard blocky trim.

 

As I said, at work so can't try this, something worth playing with. Although having no centre point may be an issue. I guess you could map middle mouse click to centre trim.... will try later.