To Trim Or Not to Trim that is the Question.

[rabbit]

Ok.

I have been reading  this and other message boards.
as well as training pages.

I know that some use Combat trim ( like i do)
but i only use it because i do not understand how when and where to use manual trim.

Alot of the better pilots say manual trim all the way. then again alot of  pilots say dont worry bout it. use the combat trim.

i do understand the concept of trim.

but in RL  it is something that you feel.  you can feel  it when you are  out of trim.

since we do not have the seat of the pants feel or the control feedback  that you would feel in Real life flight. then how do you know  when or how much manual trim to add?

what are you looking for  to tell you that you need to trim the aircraft? and how much  do you need to trim it for said manuver?

i know if  the aircraft is  trying to roll pitch or yaw when you are trying to get  the plane to fly straight and level you trim it.
that is simple.

But, in a combat situation.....  how do you know how much trim to put into the bird or take out. if you are trying to fly the plane on the edge and  you cannot feel through the  controls what is needing in the way of how it wants to be trimmed?


i am sure there are some of these  super ACM guys that could explain a few basic situations and conditions of  when and how much  trim to add .

For instance.... if you dive  from 10k @200ias starting speed to 450ias max speed,  to  bounce an enemy. how are you  trimming as you are picking up speed?
 are you just trimming like crazy hoping that you  hit the right  trim setting  to get the  plane to perform  its best? or do you have a set  thing that you look for  to tell you to add trim and more trim?

 On your Zoom out  you pull a vertical manuver  to rope a bad guy from  the 450ias dive that you are  coming out of. so, you pull a pure vertical manuver , you are losing airspeed like crazy trying to  get every last bit of E out of your ride.  what are you looking for the plane to do to tell you that you need to trim the plane up.

as fast as you gain and lose airspeed in these 2 situations. how  do you keep up with that. what tells you  physically that you need to add/take away trim from any particular  control surface?

i  think having a general guide describing  common situations  such as the above situations. on when,why, and how much trim to use. would really shed  alot of light on the mystery of aces high trim.

i know i know.....  it is a secret.. you could tell me but you would then have to kill errrrr...... wait! most  of you have killed me many times


Thanks

[Urchin]

I think I'm a bit of an oddity amoung the 'better' pilots in that I don't use trim.  I do think I'm a damn good pilot (at least in AH lol), and I don't think it is  holding me back any, but I could be wrong.  Just about the only time I ever use trim is to get myself out of a dive when I'm starting to compress.  Any other time I just use combat trim and I just work the controls to keep myself pointed in the direction I want to be pointed in.  

For instance, if I'm diving on someone and I get to 450 IAS (Which I almost never do, I chop throttle to stay at a 'controllable' speed), the only trim I'd use would be 'up elevator' to pull myself out of the dive.  I know my 109 is going to be tough to control going that fast, so I just make allowances for that fact.  

In a vertical zoom, I just point my plane where I want to be going and use the rudder to keep myself pointed there until I allow the nose to fall.  I very rarely go into an uncontrollable stall in those situations.  I think it is just a 'feel' thing, to be honest.  If you fly a particular plane for an extended amount of time, you DO get a feel for what it is going to do in a given situation.  

Oh, I also use trim if I lose a wing 'tip', not that it usually matters much in the aircraft I fly (since they are basically uncontrollable if that happens).  If you trim ailerons opposite to the wingtip you lost you can sometimes stay in the air long enough to crash or (if you are lucky) crashland at your field.

[maddog1]

I have trim programed to my second hat on Xs6 stick.... use it in steep dives and when plane is damaged..... easilier to get sick plane home when missing wingtip etc.

[Minotaur]

For dogfighting, the use of Combat Trim ends up being a personal preverence.  This especially true if you are using a plane that can take advantage of flaps to increase turn rate.  The P-38 is good example.   Another good use for planes that handle sluggishly at high speed.  The Me109 is a good example.

Combat Trim is just a "get it close" mechanism.  This get it close to trim applies to an aircraft flying in a clean configuration.  It can do some weird stuff if the aircraft is flying other than clean.

As you know the REAL purpose of trim is reduce the physical pressure on the stick.  

But...  Keep in mind that the stick is mechanically connected to the control surfaces, if the control surface moves the stick will move a corresponding amount.

In AH we feel no stick pressure and most of our joysticks are spring return to center.  AH simulates alot of things that are not felt, one is stick pressure.  

Consequently;  the simulated trim effect has another side advantage.  You can actually increase your turn rate by using trim.  This is probably the main reason for not using Combat Trim.

IMO, it just gets to be more of a hassle than it is worth.  Combat Trim works reasonable well and is seemless.  I use it 90% of the time.  

Good times not to use Combat Trim:

• Pulling out of high speed dive
• Provide limited manuverability while at high speed when controls get sluggish
• Very slow speed manuvering during a turn fight when I need just a tad more rate of turn
• When using flaps to help my turn rate
• Landing

Keep in mind that you can have Combat Trim enabled, but any time you take manual trim control it will dis-engage.  Combat Trim will re-enable by either turning it back on or by entering any Auto Pilot mode.  This is probably the most useful way to use Combat Trim.

Good Luck!

[bozon]

I dont normally use combat trim. I use it as a "quick trim" mechnizm since the manual controlls move so slowly.
so if i was trimmed for slow speed and i dive steeply, instead of using the manual trim forward - which keeps my left hand that works the views and rudder on the keyboard, away from it's task, I just hit "combat trim - on" for a sec, then "combat trim - off" and I'm close to trimmed.

why not to use combat trim constantly?
I "feel" the plane doesn't keep E as well with it.
the only reason for this i can think of, is that combat trim makes u "pull harder" moves than intended. lets say you pull some degrees on the stick - your planes slows down while turning - combat trim put more backward trim - now with the same position of the stick your angle of attack is greater.

Bozon

[Andy Bush]

Mino

I want to include info on AH trim in the article that I'm writing. What I don't understand is how trim in this sim increases turn performance. Can you explain this?

Are you looking at the high speed area of the flight envelope where air loads restrict stick movement, thus allowing trim to increase elevator authority? Or are you saying that "up" elevator trim will produce an increase in turn rate at "normal" speeds (where air loads are not a problem)?

Let's be careful with this, because if trim is programmed correctly, it should not have any effect on turn performance (excepting the high speed situation noted above).

Andy

[Urchin]

I've heard it both ways, that it does and that it doesn't.  Supposedly, you used to be able to pull the stick back all the way (at low speeds), and when I say all the way I mean before you stall, not to your belly.  Once you had the plane turning as well as you could, you could use trim to get a little extra 'back force' going, to make you turn harder.  I'd think this would make you stall though, so I don't know.  

One situation I think it could possibly be used to turn tighter in is if you are going to fast to provide maximum deflection to the elevators (not sure if this is modeled or not)- in that situation you could use manual trim to turn tighter, since it is adding the force you can't provide to get full deflection.

[Andy Bush]

What some folks don't understand on this issue is what makes a plane turn.

Lift turns the plane...changing the elevator position changes the amount of lift being produced...up to the stall or aircraft G limit. As long as the pilot can physically move the elevator to reach the stall or max G limit, then trim will have no effect other than on how much force the pilot has to exert on the stick.

As Urchin mentions, the exception is when at very high speeds in some aircraft when air loads prevent the pilot from physically moving the stick. In this instance, trim might be used to mechanically assist the pilot in moving the stick.

At very slow speeds where the pilot may have full aft stick, trimming nose up will not make the elevator more effective and thereby improve the wing's ability to produce more lift. All trim will do in this case is lessen the amount of force needed to hold the stick full aft.

So...trim does not turn the plane. The wing does by producing lift. The trim function only assists the pilot in moving the elevator.

[Blue Mako]

Combat Trim is explained in the help section of the HTC web page.  Here is an excerpt from the explanation HT wrote about it at the release of 1.04:

The method we have been using was to always give you x degrees of elevator travel than just add that degree to the current trim degree.  This leads to problems if you are slow with nose down trim, you could no longer pull the plane to the edge of stall.  This isn't how real planes fly in the slower flight envelope.  Very few planes could you not generate enough stick force to pull into stall at slower speeds.  This oversight is why people use trim in a slower turn fight and hence get an advantage by giving more up trim at slower speeds.

Under 1.04 we have change the control setup slightly.  We now scale the elevator/stick deflection to the same ending angle no matter where the trim tab is positioned.

There is another misconception that trimming your plane perfectly gives you a flight advantage.  Trimming your plane or just holding controls and pressing rudder to center the ball is exactly the same thing, and the plane will fly the same under both methods.

Note that HT explains that trim used to give an advantage, pre-1.04, it no longer does.  Moving your j/s to a particular position will give you the same control surface position no matter what trim you have set.

Just to repeat, according to HT himself there is NO[/i] advantage using manual trim as opposed to Combat Trim.

[Andy Bush]

Blue Mako

Thanks much...that was what I was looking for.

Andy

[Spatula]

Originally posted by Blue Mako


Just to repeat, according to HT himself there is NO[/i] advantage using manual trim as opposed to Combat Trim.

Apart from pulling out of compressed/control-locked dives. It still does a good job at doing that.

I mostly use CT, 99% of time. The only time i switch to manual is in the extreme outta limits of what the CT can cope with. This normally happens at very slow speeds, like landing, or at the top of a hammerhead/wingover. Or very high speeds when your compressed or control locked.  I use manual trim on most of my landings; and to rescue my dumb arnold when im compressed in a dive in my pony. In these situations i find CT not good enuf.

[rabbit]

Very good replies .

thank you all for responding.

it is pretty neat to see the  diverse flying styles that aces high has cultivated.

now these posts would make  a great referece point for a pilot new to  AH.
sometimes it is like searching for the holy grail to find easy to understand information to help the  new/novice pilot that is trying to improve his/her skills.


ill post all of my silly questions as i think of them.

once again thank you folks !!!

[214thCavalier]

I use manual trim at all times unless cruising when i select Auto mode.
I think i am possibly a minority of 1 in the way i set trim though
All the planes i fly i always set negative elevator trim before combat, some fully negative others maybe 25% and i do not suffer any lack of manouverability doing so.
Reason for setting as such for me is i hate the false detent centre position that joysticks have built in, meaning if con goes below nose you relax the stick then have to start pushing away once you hit the centre zone.
I much prefer to have a  large negative elevator setting which means yes i have to apply backpressure to fly level but in combat only the dead stay level, now if a con starts dropping into my sights or drops below my nose i can smoothly relax stick pressure and easily track and nail him without hitting the sticks dead zone near centre.
The alternative is he drops towards your sights you relax, hit the central dead zone of the stick, have to compensate for the reduced elevator movement v stick input. Then find you suddenly have to PUSH the stick away, requiring different muscle inputs, end result is you failed to smoothly track, stay on target and kill.
The only times i will use up trim is if i have had 1 elevator damaged then it does help in turns, or to pull out of a locked controls dive.
My current MA hit rate for fighters is 17% which ranks about 39th so something i do works 0k

However i would be most obliged if you all continue to persevere with the automatic combat trim option

[humble]

I've always flown with manual trim....starting pre 1.4 where it did matter a bit. historically I've found that since I tend to work the throttle hard combat trim is a little less effective since often it won't adjust to the extremes of speed and unusual attitude in a knife fight. I often used to lose the plane on the edge do to the trim settings.

98% of the time I'm able to auto trim prior to entering combat....usually I'll zoom to about 275...auto trim level....then start on in....often I'll dive and zoom....but I now my planes trimmed near the sweet spot i want. Usually I'll leave the trim alone unless I'm stuck in a real slow speed knife fight.

Again, I gave up on combat trim very early on...in a plane like the pony for example I couldnt T&B well at all with it on.

[popeye]

I use trim to keep the stick and rudder centered.  Since my stick scaling is non-linear, giving finer control near center, using trim lets me maintain that fine control at any speed or AOA.