I am new to Flight sim, as well as flying in general, and am perplexed by how to use trim?  The lesson in Flight Sim doesn't seem to help me.  Can someone please explain to me how you use it?

Use it sparingly; that's Rule #1.
It's very hard to use in FS compared to real life, and unless you have your elevator sensitivity adjusted properly, it's going to be nearly impossible to use.
But here's the idea: the trim wheel or electric trim servo controls a little tab on the trailing edge of the elevator (or sometimes it moves the whole horizontal stabilizer, but not many planes have that).
As you move the wheel, the tab deflects. When you add "nose up" trim, the tab deflects downward, which causes the elevator to "want" to go upwards while in flight (picture it). This of course makes the plane pitch up.The opposite applies to "nose down" trim.

The reason it's there is to "trim off" the force the pilot has to apply in order to maintain a certain pitch angle... to climb or descend, or to maintain a given airspeed at a given power setting. In a real airplane, it's usually possible to trim the plane so you can let go of the yoke or stick, and it will "stay put" until something disturbs it.
Took me a while, but in RL I eventually learned to fly a Cessna in a tight circle hands-off, by setting the bank, then using trim to hold the necessary "back force".

In RL, it's pretty easy, because you can feel how much resistance you're "fighting" with your hand. In the sim, it's much harder, but with a good model and some adjusting, it's very do-able.

You probably remember the lessons sayingto dial in "takeoff trim" before rolling- this helps ease the amount of force you need to rotate, and also guarantees that if your hand slips or whatever, the elevator will still tend to go up, which will keep you climbing.

Keeping in mind what I said about "trimming off force" is the key to understanding how to use it. You have to put the nose where you want it, then apply up or down trim until you can let go and the pitch angle remains more or less stable. This is where the sim makes it harder, even if  you have force-feedback controllers... in RL, you can literally feel when you have it trimmed right.

So try that: hold it where you want it, apply a little trim, let go, put it back where it cshould be, trim some more, etc.

You may find that you think you have it trimmed off, but it still dips or rises a little... some planes need a moment to oscillate before they "settle down", so be patient. Otherwise you wind up "chasing" the nose up and down, and next thing you know, it's so "out of trim" you can barely hold it level.

And use small amounts of trim, always. Trim... wait... check.... trim... wait.

Best way to learn this is in a slower plane, like the Cub... once you get the hang of trimming, try keeping your hand off the yoke or stick and climbing or desending with trim alone.


And again: check your sensitivities... for elevator, and for trim, if you're using a pot on the controller to adjust trim. Experiment- it depends very much on the plane, etc.

Interesting because in FSX Im trying to trim a 172...In the lesson, it mentions something about the airplane maintaining the speed at which it was trimmed.  How does speed come into all of this?

Thanks for your help.  I really appreciate it!

Also, for a force feedback joystick, how much would that cost?

Oh.. and if it has to be one or the other.. Put your money toward a yoke and pedals, instead of a force-feedback stick..

Don't mind him.. he thinks he's punchy from over-study (when it's actually because the Packers  won a game.. the whole state is giddy)

Ok.. now you're in trouble... What is the punishment in Cheese-head land for misspelling that name ?

This thread is in danger of becoming bogged down in complex technical explanations which can only end up causing more confusion than it resolves. The question was simple: Quote:


The simple answer is that trim relieves the pressure on the controls so that the aircraft can be flown "hands off" in all parts of the flight envelope. This takes the strain off the pilot & makes the aircraft much easier to control. Although aileron & rudder can be trimmed on some aircraft, when people refer to trim they usually mean elevator (pitch) trim which is the one most likely to require continual adjustment throughout the flight.

The method of adjusting trim varies according to the type of aircraft but can involve simple bias springs, small "trim tabs" on the control surfaces & even completely adjustable main surfaces like all-moving tailplanes (horizontal stablizers). These can be controlled by various means including levers, wheels, rotating handles & electrical switches, knobs & dials. Some aircraft can be flown in normal flight by using the trim controls alone while others have fixed trim which is adjustable only on the ground.

It's not always easy to replicate this in FS especially when relying on key strokes or push buttons. The best type of controller is one with rotary controls that can be assigned to the trim. This makes trimming much easier & intuitive until it becomes second nature. I've "flown" many FS aircraft using the rotary trim wheels alone.

One more thing. I agree that a set of rudder pedals would be more realistic but whether you use a joystick or yoke is a matter of preference. The joystick is regaining popularity in real life & many modern GA types are fitted with them. Most vintage light aircraft & aerobatic types use joysticks. Modern "fly-by-wire" jet fighters & even large jet airliners like the Airbus range feature controllers not unlike a gaming joystick. I can foresee a time when the only aircraft to use a yoke will be trainers & light twins. This is a complete reversal of how it was only a few years ago.

PS. I always thought the most realistic trim controls were those little wheels fitted to the old-fashioned analogue joysticks. By varying the neutral position of the joystick itself these work in exactly the same way as the trim controls on many aircraft.

FridayChild wrote on Dec 13^th, 2006 at 7:00am:

Unless it's completely shot it should be possible to adjust this from the FS Controller Settings. Play around with the Sensitivity & Null-zone settings.

Brett_Henderson wrote on Dec 13^th, 2006 at 7:59am:

I think that's debatable Brett. I've flown an aircraft with a yoke only once in all the years been involved with aviation. That was 40 miniutes stick time on the company Piper Aztec when going on holiday to the Channel Islands with my family back in the 1970s. With the type of aircraft I'm interested in both in real life & FS I've never felt the need to get a yoke. A set of pedals to go with my joystick would be more realistic but I'm quite happy with the separate rudder control. This is a simillar setup to my R/C transmitters which makes it useful for that too.

You obviously realise that many of the latest trainers (like your club's new Liberty XL2) have conventional joysticks. This also applies to the Diamond Star & similar types. Some modern light aircraft have a single stick mounted on a central console between the front seats & all popular Cirrus types use an unusual sidestick which reminds me of an umbrella handle sticking out of the the panel. http://www.airliners.net/open.file/1131323/M/

I suspect that yokes will eventually become a thing of the past used on those old-fashioned Cessna & Piper trainers.

I didn't intend drifting off-topic but this is a pet subject of mine. Just a couple of points.

Brett_Henderson wrote on Dec 13^th, 2006 at 12:27pm:

I wasn't suggesting that, merely that a 4 axis gaming joystick with separate rudder function suits my purposes on my home PC. My favourite joystick is the Saitek combo type with the rudder controlled by a rocker switch on the separate throttle. This also has those rotary trim controls I mentioned. I don't need a yoke & rudder pedals would be an unnecessary expense.

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Again, that's a matter of preference. I imagine it would take a bit of getting used to but I've read reports that it soon becomes instinctive. I always found toe/heel brakes awkward to use. The best idea I've seen is the automatic differential system used on the Spitfire & many other British military & civil aircraft.

Brett_Henderson wrote on Dec 13^th, 2006 at 1:44pm:

Oh, I agree but many others wouldn't.

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I can't comment as I've only seen a few small photos of the arrangement. I'll have a closer look at the next opportunity, whenever that might be. However, I found one of the reports I mentioned here. I don't know the author or his credentials.
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Ah, thanks for the photo. I can now see what you're talking about. I admit it looks a tad fiddly but I would have to try it myself to form a proper opinion.

Strangely enough the Europa Tri-gear that the Liberty is based on apparently has toe brakes. http://www.pilotfriend.com/flight_reports/reports/19e.htm

PS. Robert Goyer, the author of that report I quoted, is Senior Editor of "Flying" magazine. http://www.flyingmag.com/article.asp?article_id=317&page_number=2&section_id=11

Thanks for all the help.  I've been using the Logitech Extreme pro 3D.  Could that be making it harder than it is to trim?  Also, do you all reccomend the Saitek X52?

bok269 wrote on Dec 13^th, 2006 at 3:52pm:

Sorry, I got carried away & missed this.

I've seen some good reports on the X52 & it's similar to my old faithful X36 combo. I assume it still has those assignable rotary controls I mentioned. I would say go for it if you can afford it.

PS. Review on the X52 HERE
I see they reverted to a twistgrip rudder control instead of the switch on the X36. That seems a shame.

Brett_Henderson wrote on Dec 13^th, 2006 at 4:42pm:

The X52 has a total of 3 rotary controls that would be perfect for trim in all three axes.

I'm trying to remember if the Europa fuselage I sat in at Airventure was a trike or monowheel... but no matter- I agree that the finger-brake system is a brilliant idea from an engineering standpoint, but that setup in the Liberty (same as trike Europas) looks "fiddly," all right. Seems like there's more travel in the levers than I'd want to deal with, especially with my left hand.
It'd be better to have a sprung, pivoting bar or pad on either side of the throttle lever, running the length of its travel,so one can extend a finger to tap one or both brakes without any concern about throttle position. It'd be tempting to put buttons on the throttle handle for brakes, but that could lead to some serious "whoopsies".
I think the monowheel Europas use a single brake lever on the throttle handle, sort of like working a motorcycle hand brake, and steering is courtesy of rudder/tailwheel input. Bet that's pretty easy to learn to use.

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Flying with a stick in your left hand isn't much different than flying by yoke with just your left hand.

And for that Liberty... I'm not the only pilot who's not comfortable giving up both a steerable nose-wheel AND not having toe brakes. Like I said.. it's not that big a deal getting used to it, but it definately compromises the positive, and by comparison, precise control you get while NOT having to teach your hand/fingers/thumb new tricks. Let me assure you, it makes taxiing in a crowd, with wind, more demanding. It's a manufacturing short-cut and money saver.. pure and simple.

The more we ponder this.. the less I like the Liberty..

I don't know about the Europa, but another cost-cutting compromise that probably has a lot to do with the fact that those god-forsaken finger brakes are used, is that you can't adjust the seat ! You heard me right.. When fitting yourself into the cockpit of the Liberty, you have to actually adjust the position of the rudder pedals     The hardware/plumbing involved to make toe-brakes adjust along with the pedals (let alone having to make seperate, adjustable, stand-alone brake pedals (the Europa doesn't have toe-brakes.. it uses seperate brake pedals)) would weigh quite a bit and cost a bunch too.

These aren't innovations. Nobody said, "hey.. let's fit this thing with better, easier to use brakes". They're engineering/manufacturing/money-saving short-cuts.

Brett_Henderson wrote on Dec 13^th, 2006 at 4:42pm:

I've got the logitech right now and it uses push button for trim.  Unless of course you map the throttle to the trim, if its even possible, but I have no interest in doing that.

Thanks.  I think the main problem is a lack of patience on my part and the difficulty of trimming a 172

If you are flying the default C172, I can recommend downloading the RealAir C172 http://www.realairsimulations.com/home.php?page=home
They make great aircraft and that one is free, it has won numerous awards and is said to be much more realistic. I fly this aircraft and it does trim out out much better. If you don't like the stock colour I have a repaint you can have if you like, also some better (in my opinion) sound files.

ahh Lol just editing as noticed this has already been said. In that case I back that up.

Hey Friday, I have just found a great free model of the C150, the panel is fantastic and she flies beautifully. Have to say its the best free trainer ive come across.
(Im not connected by the way). Give her a try. Go here and check out the free downloads link
http://www.carenado.com/ecommerce/buscador.php3?categoria=3

Well, when  you try and load it, it does flag as having some incompatible parts, but if you accept them anyway it flies perfectly and everything seems to work.
Except for one thing, as I landed for the my first online touch and go I crashed and came to a grinding halt. It appears that although the Cessna has fixed gear, the sim still has the 'G' key armed.
I shall have to disable it in aircraft.cfg or wherever and that will be it sorted.

Its well worth a try anyway Fridaychild