Force trim useage (or not) with springless controls

[markturner1960]

So I use a Virpil CM3 dry clutch joystick, set so the clutches hold the stick in whatever position I move it to. My rudder pedals are teh same, MFG crosswinds, with a damper and springs removed. I have both pedals and controls set to the "FFB No springs" option in the Special page. 

With this set up, I can operate the aircraft perfectly well without ever using the force trim release button. However, all the SME videos all say you should trim, trim, trim, all the time. Is this only because they are using centering sprung  joysticks ? Or does the module require constant trimming , as in reality within DCS, because of teh way it is simulated? 

In my specific scenario, I question the point of using the force trim button as my controls hold themselves where I put them......Is this right or wrong and what benefit would I get from using the force trim ? I understand pressing it disconnects the SAS & SCAS, but generally, this would not be required, correct? 

[Vakarian]

Force trim is not only used to keep the cyclic where you left it, but it is used to recenter the SAS authority sleeve. Just look on the forums for this, it's been repeated for 1681681816 times and reiterated about the same amount by the SMEs. 

Even if you have springless controller, you should still use force trim release  

[MAXsenna]

So I use a Virpil CM3 dry clutch joystick, set so the clutches hold the stick in whatever position I move it to. My rudder pedals are teh same, MFG crosswinds, with a damper and springs removed. I have both pedals and controls set to the "FFB No springs" option in the Special page. 
With this set up, I can operate the aircraft perfectly well without ever using the force trim release button. However, all the SME videos all say you should trim, trim, trim, all the time. Is this only because they are using centering sprung  joysticks ? Or does the module require constant trimming , as in reality within DCS, because of teh way it is simulated? 
In my specific scenario, I question the point of using the force trim button as my controls hold themselves where I put them......Is this right or wrong and what benefit would I get from using the force trim ? I understand pressing it disconnects the SAS & SCAS, but generally, this would not be required, correct? 

Hi Mark! I assume you meant "Without springs and FFB". And yes, you have to press trim to tell the system of your intentions. Same in the Ka-50, unless you turn it off.
Cheers!

Sent from my SM-A536B using Tapatalk

[McGraw]

I asked this for pretty much the same reason as you except I am using racing peedals for now so was "forced" to use it for my pedals.

Everyone says do it. If it isn't really causing you an issue at the moment then a future FM update might start causing you issues

[Tepnox]

The less you use the trim button - the more you will get the SAS saturation warnings. This is the case because you don't actually reset the SAS stabilization points as stated above.

And also you are fighting the SAS the whole time when not using the trim button - that is not ideal.

I have a similar PC setup with dry clutch for my Warbird-D with extension and using the Virpil ACE Torq Pedals with Dampener.

I am using and holding the force trim button every time when changing inputs in normal flight above 40 knots and also for the first hovering after startup.

The only exception I do not use the trim button that often is when hovering is stable and just making minor changes to the inputs. When landing and below 40 knots I also do not use the trim button at all because I want the yaw stabilization to help keeping the nose on point.

So better try and find a good button on your Hotas that you can penetrate very often without getting a numb thumb and try to stick to this procedure ;D

Even with dry clutches you can not replicate the counter-pressure a stick would normally have in the real Apache while already trimmed. Using the trim button would release the pressure on the stick in the real Apache - so that lack of immersion on our peripherals is something we sadly have to deal with in DCS.

Edited November 12, 2023 by Tepnox

[markturner1960]

All, thanks for the replies - I should add that I have indeed read many threads and watched many videos regarding this. I was asking as when I fly without using the trim button, I dont have any issues. Occasionally, I will get a SAS saturated, but it generally goes away. I have tried flying and trimming as you describe above, but I could not really notice any difference. Hence the post. 

Not disputing the necessity, or what you are all telling me - I guess the question then becomes I wonder why I am not noticing any degradation in the flight experience when not trimming .....? 

@Tepnox -can you detail what "fighting the SAS" might feel like and manifest as ? 

When I pick the aircraft up from a hover, I really have very little input - maybe a tiny bit of right pedal and back cyclic. What does trimming at this point do? And how does that manifest in what I feel? As without trimming I can happily sit there in a nice stable hover. If I trim, it seems to make no difference. I have all my controls mapped and when flying, trty and remember to trim, but often, it slips your mind.....in these situations, nothing bad happens......? 

I spent 30 minutes watching trim videos from Casmo, Bradmick & Redkite this morning, but confess I still dont feel how it relates to my flying experience. I will re watch! 

Who has the most current and relevant you tube vid? As I feel a lot has changed in various updates ......

And in the same vein, any good articles and reading on force trim and the SAS system? Both the Chucks guide and quick start don’t seem to cover it….or I have not been able to find it in them……

Edited November 12, 2023 by markturner1960

[markturner1960]

Update: In this video

and the comments after, Casmo discusses this. Basically, trim still needed to recentre the SAS. In the light of that, perhaps I should fine tune the question to the following:

What sort of manouvres are going to need the SAS recentering and is there a need to be trimming all the time, as advocated on some guides, or to hold the trim while manouvering ? Bear in mind with a sprung joystick, yes you would neeed to trim as advised, due to it recentering itself -  I am talking specifically about my situation with a springless joystick. 

I have tried to dig a little deeper into how the SAS works in the situation we are discussing and came up with this from Bradmick:

 "The helicopter SAS will “saturate” over time and run out of authority. The green plus signs will tell you where the SAS is with regards to its “authority”. You can’t just trim it and leave it permanently there. As the FMC commands the SAS to respond to exterior stimuli while trying to maintain a stable hover or a desired or commanded attitude, it will use the SAS authority it has available to it and eventually run out of it. To return full SAS authority you have to recenter the SAS servo. To recenter the SAS and return it’s authority to maximum, you have to press and hold the force trim release switch for 3 to 5 seconds to recenter the SAS. Based on your description you allowed the SAS to saturate and it can no longer help you maintain a stable position."

So, in the light of that response,  I guess in theory, the answer to my question would be that you would, rather than trimming all the time, simply re set the SAS servo when it requires, which would be indicated by the SAS saturated message? Incidentally, some intersting discussion inthe thread where I lifted Bradmicks answer from, here: 

 

Thanks all for input on this interesting subject. 

Edited November 13, 2023 by markturner1960

[admiki]

If I were you, I would trim more often than SAS saturated messages prompts. By the time message is there you have already lost SAS authority.

 

[UncleStains]

I, too, fly with an unspring clutched joystick. When I first learned about this, I started flying with the control indicator window on for a while to figure out how the system works. It seems like hitting the trim release whenever you get the stick where you want it does the trick. I'll sometimes hold it when making a big move, but that doesn't seem to make much difference outside of long, arcing turns like flying a landing pattern. 

[bradmick]

No, you need to trim and not wait for the SAS saturation advisory. Waiting until the advisory presents means the aircraft is likely already doing weird things input wise that you’re having to fight against. Be a pilot, do pilot stuff and proactively trim. If you need to make large maneuvers and inputs, hold the trim interrupted, and release it when you’re back to level. This is the way, regardless of your physical hardware. 

[ruiner_]

I just wish the different trimmer modes didn't have such a large discrepancy in deflection rate compared to the centering stick option. 

Does no one else here using an unsprung stick have this problem?

Edited November 14, 2023 by ruiner_

[markturner1960]

Can you elaborate?

 

[ruiner_]

6 hours ago, markturner1960 said:

Can you elaborate?

 

When in the central trimmer mode, the in game cyclic position lags only slightly behind the physical position of the stick. In either of the other two trimmer modes the in game cyclic moves extremely slowly, often up to a second or more behind the physical stick. 

You can see it by bringing up the control indicators with right ctrl enter. 

[mason.zh]

On 11/12/2023 at 1:56 PM, markturner1960 said:

, any good articles and reading on force trim

The helicopters with force trim release systems are not 'dead stick' all the time. Without the force trim release button being pressed, moving the cyclic away from the center position and releasing the cyclic will cause the cyclic to move back to its center position, just like other normal aircraft would do. In other words, the further you move the cyclic from its centered position, the more tension/force it will be required to move the cyclic. 

In Apache, when the force trim release button is NOT pressed, it means the force trim system is engaged:

Quote

The magnetic brakes lock and the spring assemblies resist control movmement.

Pressing the force trim release button will release the magnetic and allow movement of the controls without any resistance. 

For the article, you can check this one: https://www.spinningwing.com/the-helicopter/control-forces

Also, these 2 videos will explain:

The force trim system in Apache is similar but with SAS involved.  That's why if you want to do some big maneuver the best practice is to hold the force trim release button, this will release the magnetic brakes and allow the cyclic to move freely without resistance, as well as re-center the SAS servo and de-active the SAS with only SCAS engaged. Once the maneuver is finished and the helicopter is in the desired flight state, releasing the force trim release button will cause the cyclic and pedals to stay in the new center position. 

Most of the helicopters in the world with such system do not have any limitation on how long you can press the FTR button, but some old Russian helicopters such as Ka-32 has 0.5 seconds limit on holding down the FTR button. If you want, you can find some Mi-8 landing video, the 'click' sound is the FTR button being pressed and released, you will be surprised how often the FTR button is being used. 

[Schlomo1933]

Check if u don’t have Force Feedback in the Options enabled