Combat Trim?

[shiv]

Shiv you can take this a bit further and trim for 0 G at cruise speed. This makes it easier to hit 0 G for max accelleration, just release the stick, and tends to be close to level trim at max speed.

Ah, I think I see. I'll give it a try, thanks FLS.

[Traveler]

Searched and read a lot of opinions and unrelated posts regarding combat trim.  I think it would be very useful to state whether this is true or not in the help or training section.  I really did think it was pulling me around faster using full elevator up trim, but I don't know for sure.  Who would know for sure?  HiTech?

 

You may want to go to a web site for flight training, and read what an elevator trim tab is used for.  That might help explain the concept for you.  

[Midway]

You may want to go to a web site for flight training, and read what an elevator trim tab is used for.  That might help explain the concept for you.  

http://www.flightlearnings.com/2009/09/12/secondary-flight-controls-part-four-–-trim-tabs/

Just did, and it does.  Thank you.  

[Midway]

When you set full trim up the trim tab is actually down in order to force the elevator up.
As was already mentioned, trim cannot increase turn rate.

Ok, again... just so I fully understand this...

I do understand the use of trim tabs and how their opposite deflection from the elevators removes stick pressure, but in terms of just the aerodynamics (of which I know little if anything)... if I have elevators full up position and hold them there with sufficient force that they won't move on their own.... and then I dial elevator trim tabs full down (trim tabs move up full deflection also), wouldn't I get a greater nose up angle?

In other words, seems like trim tabs can give you more, but you have to move them opposite of what you would think and hold the elevators in place (not allow the trim tabs to counter the elevator movement).

If all that true, then I should use opposite manual trim to maximize full nose up.  Correct?  If not, why not since the trim tabs would now add aerodynamically to the elevator's positioning the nose up?

 

[Scotty55OEFVet]

I keep it on all the time except only when I am in a high speed dive, especially when dive bombing.  Many aircraft are adversely effected by the CT once a certain speed it reached, as it automatically raises the nose up (rather abruptly I may add) and effects the pitch of the aircraft.  I notice it most in the Typhoon and Mossi Mk IV.  Once I have the nose back up I toggle the CT back on, rinse and repeat if need be.

While in the air doing the air vs air thing, I always keep it on.  I only toggle CT off when in the high speed dives.   

Great description...I agree 100%. I played for so long with CT on and like you said, in a dive as your speed increases you rnose does begin to pull up as you said very abruptly and can cause accuracy, as you said, divebombing or strafing to below 50% in some situations. Lately, I have found that when I am divebombing I take CT off and my accuracy is something like 4 outta 5 as compared to maybe 2 or 3 outta 5 at given altitudes. It would be interesting to have someone run some tests...maybe Ill take the time and go into Offline or the TA and run maybe 20 runs with CT on/off and Ill post the results.

[Ack-Ack]

Searched and read a lot of opinions and unrelated posts regarding combat trim.  I think it would be very useful to state whether this is true or not in the help or training section.  I really did think it was pulling me around faster using full elevator up trim, but I don't know for sure.  Who would know for sure?  HiTech?

 

Again, if you were to stop typing on Channel 200 long enough and search the forums, you'll see that you are incorrect in your perception of using elevator trim to turn tighter in a turn.  You'll even see HiTech's comments in many of those threads debunking the myth.

This debate is nothing new and comes up every so often and is debunked each time.

ack-ack

[Midway]

Again, if you were to stop typing on Channel 200 long enough and search the forums, you'll see that you are incorrect in your perception of using elevator trim to turn tighter in a turn.  You'll even see HiTech's comments in many of those threads debunking the myth.

This debate is nothing new and comes up every so often and is debunked each time.

ack-ack

Ok, I read every hitech post re trim. It still doesn't explain why having full up elevator, holding that and then adding opposite trim to move the trim tabs up as well would not move the nose higher.  I understand it would require more force to hold the elevators since the trim tabs would try to work against you, but the point is by creating more force by adding trim tabs that add to the angle of the elevators you should get more nose up angle.

Elevators deflected up with trim tabs deflected up should equal more force pushing the tail down and nose up.

If not, why not?

[Traveler]

Ok, again... just so I fully understand this...

I do understand the use of trim tabs and how their opposite deflection from the elevators removes stick pressure, but in terms of just the aerodynamics (of which I know little if anything)... if I have elevators full up position and hold them there with sufficient force that they won't move on their own.... and then I dial elevator trim tabs full down (trim tabs move up full deflection also), wouldn't I get a greater nose up angle?

In other words, seems like trim tabs can give you more, but you have to move them opposite of what you would think and hold the elevators in place (not allow the trim tabs to counter the elevator movement).

If all that true, then I should use opposite manual trim to maximize full nose up.  Correct?  If not, why not since the trim tabs would now add aerodynamically to the elevator's positioning the nose up?

 

Your missing a key concept.  The elevator is what controls the nose of the aircraft.  The trim tab controls the pressure you feel fed back through the control.   Understand.   If the elevator is deflected 100%  that’s all there is , changing the trim tab does not give you more elevator deflection.   You only get 100%.   What the trim tab gives you is the ability to make an elevator deflection of 100% with only using 50% of your muscle power.   Get it.  It removes or lowers the amount of muscle power you need to use to get 100% deflection?

[Midway]

Your missing a key concept.  The elevator is what controls the nose of the aircraft.  The trim tab controls the pressure you feel fed back through the control.   Understand.   If the elevator is deflected 100%  that’s all there is , changing the trim tab does not give you more elevator deflection.   You only get 100%.   What the trim tab gives you is the ability to make an elevator deflection of 100% with only using 50% of your muscle power.   Get it.  It removes or lowers the amount of muscle power you need to use to get 100% deflection?

I believe I fully understand that.  But think of it in reverse.  If you use opposite trim it requires more muscle.  Why?

I think it is because you're getting more nose up force requiring you to offset with the additional muscle effort.

Also, I am not saying you would get more elevator deflection, I am saying the trim tabs would add to what the elevators are already doing. -- lower the tail, raise the nose further. 

[Traveler]

I believe I fully understand that.  But think of it in reverse.  If you use opposite trim it requires more muscle.  Why?

I think it is because you're getting more nose up force requiring you to offset with the additional muscle effort.

Also, I am not saying you would get more elevator deflection, I am saying the trim tabs would add to what the elevators are already doing. -- lower the tail, raise the nose further.  

What makes the aircraft turn?  If your answer is anything other then lift, your wrong.

The elevator controls the AOA of the wing, Excessive lift, equal climb, Roll the aircraft left or right and excessive lift = a turn.

[Midway]

What makes the aircraft turn?  If your answer is anything other then lift, your wrong.

The elevator controls the AOA of the wing, Excessive lift, equal climb, Roll the aircraft left or right and excessive lift = a trun.

Yes and I believe moving the trim tabs in the same direction as the elevators would give you more AOA. 

[Ack-Ack]

Yes and I believe moving the trim tabs in the same direction as the elevators would give you more AOA. 

It doesn't.

ack-ack

[Midway]

It doesn't.

ack-ack

  Why?

[Traveler]

ack-ack is 100% correct.  all using trim does is lower the forces you need to use to move the elevator to reach critical AOA.

[Midway]

ack-ack is 100% correct.  all using trim does is lower the forces you need to use to move the elevator to reach critical AOA.

Just made a paper aeroplane, gave it elevators and gave it trim tabs on the elevators.  It loops up faster with trim tabs deflected up and elevators deflected up.

  when lacking a full explanation, experimental evidence helps, on occasion.