Forced Trim

[gdotts]

This is the way I am seeing the Warthog/Xbox controller system for Apache. In all the Warthog exampled it shows one force trim button on the joystick in a up direction only for use.  The Xbox controller shows the D pad with force trim giving "up-right-down-left" abilitys when no modified buttons are pressed, I am guessing.  So again I am guessing I hand off to myself from the Warthog for the Xbox to handle the forced trimming needs of the helicopter? Just trying to get a grip on how this is to go! I have autocad sheat sheets I have used inall my DCS planes.  Helicopters is a new area for me. Thank you.

[Mad Dog 762]

Trim in a helicopter is nothing like trim on a fixed wing and it take some getting used to.  Think of it more as a trained monkey that holds the stick for you where you want it.  So you're in straight fast forward flight with the cyclic pushed forward.  Rather than having to hold it there the whole time, you push the trim button and the trained monkey grabs the stick and holds it there for you.  Thats the basic function.  If you use a hold mode, you have a smarter monkey that can keep it at the attitude or altitude you want.  

 

[gdotts]

Perfect... explained to perfection guys.  Now I know what I am dealing with!!

Thank you

[gatordev]

I'm piggy-backing on this thread because it touches on a concern with the Apache module I'm hoping some of you might be able to help with, specifically about using Force Trim in a computer sim.  I've always found computer game force trim to be problematic because the joystick doesn't move as much as a real helicopter cyclic does, so pushing the joystick forward some small amount forward becomes relatively imprecise when trimming in most games.  I've been getting familiar with DCS by learning A-10C II, and I was hoping to move to the Apache for helicopter ops once it's released, but I'm worried about controllability making it less "fun" because it has the limitations of a computer game.  Buying yet more hardware (ie, cyclic extension) isn't the answer for me at the moment.

 

On 11/17/2021 at 8:31 PM, Mad Dog 762 said:

Trim in a helicopter is nothing like trim on a fixed wing and it take some getting used to.  Think of it more as a trained monkey that holds the stick for you where you want it.

 

That's not necessarily true for a lot of helicopters.  Many have trim that functions very much like fixed-wing.  Which is why below was interesting to read and brings up some questions:

 

On 11/17/2021 at 5:19 PM, kgillers3 said:

The ah64 doesn’t have a nose down nose up left wing right wing style force trim. Hat up is force trim release, it releases the mag brake allowing you to reposition the cyclic and the pedals where you want the new center of force feedback in the aircraft and it’s also how you communicate with the fmc on what you want the aircraft to do. 
 

hat left is your hold modes, which are based off of your speed, slow you have position hold and it’s gonna try to hold you there, then you have velocity and attitude holds. Pushing it again will disengage this function. 
 

hat right is altitude, radar or barometric based off speed or altitude it automatically selects which. Hitting it again will disengage.

hat down drops both attitude and altitude holds. 

 

I'm coming from a -60 (and EC-135), so it looks like the trim/autopilot/AFCS functions/modes are significantly different, but this helps me tailor my question a bit more...  Is there some magic sweet sauce in making a game joystick (Warthog in my case) usable if your primary means of manipulating airspeed/controllability is via force trim versus using a dedicated coolie hat trim?  Reducing spring tension is only an answer to a point, as you still need to be able to take your hands off the stick and have it hold position (centered in the case of a Warthog).  Reducing null zone can help, but only to a point.

Admittedly, I need to play with null zone and sensitivity some more, but flying the Huey wasn't as much fun as I was hoping (just flying, not engaging anything) because I found I was fighting the controls within the sim much more than I ever have in a real helicopter (well, except maybe first learning to hover).  There's lots of fans of DCS helos, so there's got to be a way to make it more "fun," so curious for input from the group.

[kgillers3]

1 hour ago, gatordev said:

I'm piggy-backing on this thread because it touches on a concern with the Apache module I'm hoping some of you might be able to help with, specifically about using Force Trim in a computer sim.  I've always found computer game force trim to be problematic because the joystick doesn't move as much as a real helicopter cyclic does, so pushing the joystick forward some small amount forward becomes relatively imprecise when trimming in most games.  I've been getting familiar with DCS by learning A-10C II, and I was hoping to move to the Apache for helicopter ops once it's released, but I'm worried about controllability making it less "fun" because it has the limitations of a computer game.  Buying yet more hardware (ie, cyclic extension) isn't the answer for me at the moment.

 

 

That's not necessarily true for a lot of helicopters.  Many have trim that functions very much like fixed-wing.  Which is why below was interesting to read and brings up some questions:

 

 

I'm coming from a -60 (and EC-135), so it looks like the trim/autopilot/AFCS functions/modes are significantly different, but this helps me tailor my question a bit more...  Is there some magic sweet sauce in making a game joystick (Warthog in my case) usable if your primary means of manipulating airspeed/controllability is via force trim versus using a dedicated coolie hat trim?  Reducing spring tension is only an answer to a point, as you still need to be able to take your hands off the stick and have it hold position (centered in the case of a Warthog).  Reducing null zone can help, but only to a point.

Admittedly, I need to play with null zone and sensitivity some more, but flying the Huey wasn't as much fun as I was hoping (just flying, not engaging anything) because I found I was fighting the controls within the sim much more than I ever have in a real helicopter (well, except maybe first learning to hover).  There's lots of fans of DCS helos, so there's got to be a way to make it more "fun," so curious for input from the group.

In dcs when you hit force trim in game it holds that position and you reset your joystick back to neutral position. Then force trim reset will reset so game cyclic position matches your controllers input. 

[kgillers3]

@gatordev your setup is better than when I first started playing dcs. I’m sure you’ll find something that works for you, you don’t have to have a crazy setup. You do need to understand how the force trim works in dcs and how it’s augmenting for the lack of a force feedback system. If you know that it’ll fly fine with a couple expected force trim overshoots when you reset the position. 
 

as far as taking hands off stick, yes if you get comfortable with the sensitivity settings and the sas and hold modes should alleviate some of that work load depending on your flight profile. Aircraft trimmed properly. Honestly though I’m assuming by the 135 you meant Lakota so you had an opportunity to be in the sim which undoubtedly did not fly exactly like the real aircraft. Again an assumption. So really it’ll be practice with your current setup and learning what those control inputs feel like. 

Edited November 27, 2021 by kgillers3

[Scaley]

@gatordev To be honest the main thing I found that made DCS helicopters much more controllable and generally comfortable to fly was getting the stick down off my desk and mounted somewhere you can rest your forearm like you would in the cockpit.  After that the next highest yield is spring tension, but like you've already said the warthog grip, being a big old lump of metal, does impose some limits on how far you can go both with spring tension and any extensions.  

The DCS trim implementation in the UH-1 does take some getting used to, but it absolutely does work once you've gained some muscle memory.  You have beeper trim in the 135/145 right?  I'm guessing coming from that to a single button system AND it being an odd implementation it's going to be a good few hours before your brain gets it, but it will eventually.  I've been flying the UH-1 in DCS for maybe 15 hours and at this point I can trim out some pretty big inputs, and not only hit a reasonable "hands-off" setting most of the time, but also my brain has figured out how long DCS blends the existing control input and the trim position over so there is no big "bump" that you get when you first start using the system.  

[gatordev]

Thanks for the replies.  Some thoughts/replies...

On 11/27/2021 at 5:49 PM, kgillers3 said:

You do need to understand how the force trim works in dcs and how it’s augmenting for the lack of a force feedback system. If you know that it’ll fly fine with a couple expected force trim overshoots when you reset the position. 

That's a great way to explain it...force trim overshoots.  Again, I can see the "overshoots" being more refined with some stick sensitivity adjustments, but that can only go so far with the spring tension.

On 11/27/2021 at 5:49 PM, kgillers3 said:

Honestly though I’m assuming by the 135 you meant Lakota so you had an opportunity to be in the sim which undoubtedly did not fly exactly like the real aircraft. Again an assumption. So really it’ll be practice with your current setup and learning what those control inputs feel like.

The EC-135 (H135 now) is the little brother to the Lakota (-145, which is an updated BK117).  I don't have time in the 145, but several hundred hours in the 135 (with a 2 1/2 axis autopilot) along with several thousand in the Navy versions of the -60 (which has a very robust 4-axis autopilot).  All that said, learning the control inputs in DCS is no doubt the long-term solution, just like learning the control inputs in any sim versus real-life.  I guess part of what I was asking/commenting on based on your description of how the Apache works (ie, apparently no coolie hat trim) was having to "relearn" the idea of force trim only from my -206 days in flight school.  Basically, it's good to know going in that it won't be like what I'm used to with a FT/coolie hat combination.

On 11/27/2021 at 6:39 PM, kgillers3 said:

Are you saying you don't want to use the force trim, you just wanna fight against the spring the entire time? If that's the case yeah, uncomfortable, but yeah. 

Negative, not what I was saying, but I think we may have what I meant sorted now. 

On 11/30/2021 at 3:50 PM, Scaley said:

You have beeper trim in the 135/145 right?  I'm guessing coming from that to a single button system AND it being an odd implementation it's going to be a good few hours before your brain gets it, but it will eventually.  I've been flying the UH-1 in DCS for maybe 15 hours and at this point I can trim out some pretty big inputs, and not only hit a reasonable "hands-off" setting most of the time, but also my brain has figured out how long DCS blends the existing control input and the trim position over so there is no big "bump" that you get when you first start using the system.  

Correct, both the -60 and the -135 have beeper (coolie hat) trim as well as FT.  FT is more of a reset and then you work around it with either tension or coolie hat (although the -135 also has A-TRIM, which will adjust force trim for you below a certain speed I can't remember so you don't even have to push the FT release, but that's a whole different discussion).

But you sum it up well by mentioning the "big bump."  That's what has been a frustration with playing around in the H-1, knowing it was only going to be a FT bird vs a beeper trim bird.  Sounds like I just need to keep playing with sensitivity and a little null adjustment and see what I can make "fun."

Edited December 5, 2021 by gatordev

[kgillers3]

@gatordev Yeah man, you gotta manually trim it out like the ol 206.  It has assists but gotta do the ol stir the stick thing and set it right.  I hope if you do get it you enjoy it

Edited December 5, 2021 by kgillers3

[gdotts]

So forced trim IS the Autopilot for the AH-64D.   Hover mode, I guess, is the HUD representation to "guide" you with a look straight down for you to adjust you cyclic with?

[jnr4817]

This is a great discussion. Besides the modes you have described, is there an autopilot for shooting approaches? Or do you need to trim in the aircraft and manually fly the approach with the help of each mode already discussed?

[gatordev]

1 hour ago, kgillers3 said:

above 40, 2 things happen. You have heading hold which is automatically on when the aircraft is off the ground, and force trim release is not pressed. Another mode comes active above 40 which is turn coordination, which helps keep the aircraft in trim during turns. Then reverts back to heading mode during level flight. 

I was curious about that and figured that at least HH and TC would be automatic at some point in the flight profile.  Good stuff.  Thanks again.

[gdotts]

Is there a differnce between the Force Trim release (which I now understand is for recentering the joystick) and the FMC Release Switch?

[gdotts]

Talk is Apache is probably going to be like Hind as far as Autopilot is concerned.  That being said.... Hind also has all the "Trim Hat" commands (IE: Nose down, Nose up, Roll left, Roll right) for fine tuning the in flight controls....PLUS the Trim button and Trim Reset used for the "Force trim" function.  My question is will Apache have the Hat trims too like the Hind for fine tuning the in flight controls?  Ka-50 and Huey does not have any "Trim Hat" commands at all in their Control Options but both do have the Trim control button and the Trim Reset for the "Force Trim" function along with their own autopilot commands Thank you!

[Raptor9]

1 hour ago, gdotts said:

My question is will Apache have the Hat trims too like the Hind for fine tuning the in flight controls?  Ka-50 and Huey does not have any "Trim Hat" commands at all in their Control Options but both do have the Trim control button and the Trim Reset for the "Force Trim" function along with their own autopilot commands

No trim hat for fine tuning. Just force trim interrupt.

There is no "trim reset" in real helos. That is a DCS "game-ism" that was added due to the way DCS simulates force trim for non-force feedback sticks that are spring-centered and not held in place.

[Lurker]

1 hour ago, gdotts said:

Talk is Apache is probably going to be like Hind as far as Autopilot is concerned. 

From what I understand (thanks kgiller3 and Raptor9) the autopilot is going to be nothing like the Hind's AP Channels.