Trimming sensitivity

[Sylosis]

Hi,

 

Really simple question when it comes to triming the F5.... Is there anyway to reduce how sensitive the triming is on this plane?

 

I'm asking because, compared to other planes (the Mirage comes to mind...), and also considering my past experience on other sims (XP11 mostly), I find the F5 to be impossible to trim. I can understand that each plane behaves differently. But I just can't level the F5. I've never been able to do it.

 

It's just too sensitive. Whenever I am trying to stabilize at a certain airspeed, for roll trim (if I have only one missile left for example) and pitch, I just can't get it leveled. There is always some movement. Not only am I always slightly rolling on one side, but I'm also oscillating around a certain altitude.

 

I thought maybe it was my joystick, but I recently got a new one, and it didn't do much. And anyway, the trim is set to my joystick hat, so it's not an "axis" type of input.

 

So ya, maybe I just suck at triming (but then I'm able to trim the Mirage for example), but if there is something to adjust sensitivity, I'd really like to know.

[Svend_Dellepude]

You need to stabilize in pitch before you can trim the roll channel. But it is indeed very sensetive in roll trim channel.

Nothing to do unless BST adjust it.

[WildBillKelsoe]

the behaviour described is normal due to dissymmetry of lift acting on one wing while the other wing is dipped and wants to go down. add to these presence of winds which alter dynamics of airflow on each cardinal heading. if by oscillation you refer to going up 100 feet, then down 400 feet, then up 500 feet and then down 300 feet (random VVI), then youre not at the trim speed.

 

to find out the trim speed you need to clock three things: the tachometers (to cancel a complication if you have split throttle, set R and L RPMs to equal), trim nose up while level and decelerating to takeoff calculated speed, then as soon as that speed is closer down, clock the final player - VVI. Now all you need to do is adjust power in fractions of percentages (zoom in all the way to see whites between tick marks on tachometer), adjust by 0.5% till you notice nose coming up(VVI increase), then reduce by 0.5% till you notice nose dropping down (crossing 0 ft/min), add power, rinse and repeat.

 

Also if you could zoom in on bank indicator, set a shallow bank angle for that speed. This will get you orbiting a wide arc, but also reduce your oscillations. they can not be eliminated unless you hold a stick back with nose down trim.

[Sylosis]

the behaviour described is normal due to dissymmetry of lift acting on one wing while the other wing is dipped and wants to go down. add to these presence of winds which alter dynamics of airflow on each cardinal heading. if by oscillation you refer to going up 100 feet, then down 400 feet, then up 500 feet and then down 300 feet (random VVI), then youre not at the trim speed.

 

to find out the trim speed you need to clock three things: the tachometers (to cancel a complication if you have split throttle, set R and L RPMs to equal), trim nose up while level and decelerating to takeoff calculated speed, then as soon as that speed is closer down, clock the final player - VVI. Now all you need to do is adjust power in fractions of percentages (zoom in all the way to see whites between tick marks on tachometer), adjust by 0.5% till you notice nose coming up(VVI increase), then reduce by 0.5% till you notice nose dropping down (crossing 0 ft/min), add power, rinse and repeat.

 

Also if you could zoom in on bank indicator, set a shallow bank angle for that speed. This will get you orbiting a wide arc, but also reduce your oscillations. they can not be eliminated unless you hold a stick back with nose down trim.

 

You might be pointing at what I do wrong. I think I'm not doing the right "sequence" if I can say. Suppose I am climbing to 15 000 ft. And that at 15 000 ft I want to fly at 270 knots. I tend to bring my nose down manually, adjust throttle to be close to stable at 270. Try to adjust the trim to have the pitch stable. And that is where problems appear. Each touch of the trim button makes me go from either +300 ft/min to -300 ft/min, etc. I guess I should trim the pitch to being close to stable (say +300 ft/min) and play with the THROTTLE to make the nose go down. Is that what you were explaining?

 

At the moment I don't use the throttle to correct pitch and make plane stable. This is probably my mistake.

[Max_Rogue]

Are you able to record your gameplay?

 

I flew on NTTR last night, taking off from Nellis. I did my turn, to fly west over Vegas, set my trim almost immediately, and walked away to get a drink. It stayed pretty level, except a SLIGHT right bank, because the right tank is heavier.

[Sylosis]

Are you able to record your gameplay?

 

I flew on NTTR last night, taking off from Nellis. I did my turn, to fly west over Vegas, set my trim almost immediately, and walked away to get a drink. It stayed pretty level, except a SLIGHT right bank, because the right tank is heavier.

 

Good idea, I could try to do this and share, so that you guys can give some advice as to what is wrong with my way of trimming the aircraft.

 

I'll look into perhaps the NVidia app to record or whatever and post on youtube. Might not be today, but in the next few days I'll try and share.

[Erk104]

Trimming the F-5 is pretty much a constant thing I can get mine pretty stable like Max explained I can walk away for a short time and come back but no more than 15 or 20 seconds.

 

I get the pitch in the ball park then play with the throttle. Adding power to bring the nose up gradually and reducing power to bring the nose down. It s a gradual thing though using the tiny dial inside the big RPM dial to gage like 1-5% at a time.

 

 

I try not to mess with the aileron trim normally its spot on at take off and every time I mess with it I can never get it back to what it was before.

 

 

Sometimes if you do bump it you can get it centered close using just a touch of rudder trim along with aileron trim. That's the best I have been able to do.

[Balzarog]

Trimming the F-5 is pretty much a constant thing I can get mine pretty stable like Max explained I can walk away for a short time and come back but no more than 15 or 20 seconds.

 

I get the pitch in the ball park then play with the throttle. Adding power to bring the nose up gradually and reducing power to bring the nose down. It s a gradual thing though using the tiny dial inside the big RPM dial to gage like 1-5% at a time.

 

 

I try not to mess with the aileron trim normally its spot on at take off and every time I mess with it I can never get it back to what it was before.

 

 

Sometimes if you do bump it you can get it centered close using just a touch of rudder trim along with aileron trim. That's the best I have been able to do.

 

Trim isn't meant to be a "straight and level autopilot." Too many factors affect the trim of an aircraft for that. You burn fuel from a wing tank that causes that wing to be lighter, less fuel means less weight which increases speed and changes the weight to drag ratio. Trim is there just to help keep you from fighting the stick. You still have to fly the aircraft. Trim to where you have to apply only slight pressure on the stick to maintain straight and level, and use the throttles to change altitude while maintaining straight and level attitude.

[VampireNZ]

As stated above - trim isn't autopilot, so don't expect it to be a set-and-forget auto-leveller.

 

I have noticed the F-5 is very sensitive to any asymmetric conditions such as stores, fuel load etc. If you can't get a decent trim with the ailerons try using the rudder trim as well, as it should provide for a 'finer' adjustment of roll trim.

[WildBillKelsoe]

You might be pointing at what I do wrong. I think I'm not doing the right "sequence" if I can say. Suppose I am climbing to 15 000 ft. And that at 15 000 ft I want to fly at 270 knots. I tend to bring my nose down manually, adjust throttle to be close to stable at 270. Try to adjust the trim to have the pitch stable. And that is where problems appear. Each touch of the trim button makes me go from either +300 ft/min to -300 ft/min, etc. I guess I should trim the pitch to being close to stable (say +300 ft/min) and play with the THROTTLE to make the nose go down. Is that what you were explaining?

 

At the moment I don't use the throttle to correct pitch and make plane stable. This is probably my mistake.

 

Yes that is your mistake. Its as I suspected youre picking a speed and fighting with it using trim.

 

Instead, you maintain a lesser speed that goes along with trim if you want a near stable flight (the depletion of fuel, ordinance, gun, imbalance between R and L fuel tanks will NEVER give you hands off flying) you pick a speed that gives you a positive climb (above zero on VVI with trim up applied). That way, you can be certain that if the throttles are left untouched, the stick is left untouched, even if the nose dips for some time, the aircraft will accelerate and on its own want to go back up.

 

For orbiting, I suggest, as someone explained, to use rudder trim hand in hand with aileron trim. Do not expect FSX styled zero oscillations with any bird in DCS unless it has a dedicated three-axis autopilot, which you clearly dont have here. That is the joy of flying without autopilot to those who appreciate it.

 

IIRC there was an article published by somebody describing how trimming should be done in DCS A-10C. I suggest you locate this article because I can't. It was probably a blog post too.

 

here

 

http://kriegsimulation.blogspot.com.eg/2010/10/dcs-10c-warthog-angle-of-attack-watch_24.html

http://kriegsimulation.blogspot.com.eg/2011/01/dcs-10c-warthog-210-kias-speed-to.html

also read the 220 kias article also from same blogger.

 

cheers

Edited July 12, 2017 by WildBillKelsoe