C172 Trim Not Correct

[andrew737]

In the 72 different type planes I've flown during my life I don't remember ever LOOKING at the trim

My experience differs for the sim. I use a button assignment on the controller with a repeat slider full right. I use the same technique I would use in the real plane. I simply apply trim until the pressure neutralizes. Works like a charm.

Hi Dudley

With respect unless we all have control loading (I do and I use Brunner Elektronic Yoke & Rudder Pedals) then I cant see how we can indeed possibly trim as we do a real plane - do you use control loading Dudley?

Kind Regards

Andrew

[andrew737]

Hello Dudley! I don't know if Andrew is referencing the simulated trim movement ratio vs real world. I still have to try and test the behavior in the sim.

I just figured, hey why not grab the airplane and fly since wx was okay and I needed to make a run to the airport anyway to drop off a cleaned cover. I mean quit twisting my arm!!

I am uploading a completely unedited video for now, just because I'm lazy. I'll note the time of the test, but it's otherwise a full flight from start to finish. Unfortunately, the G1000 is invisible to the Gopro for whatever reason, but you can see my hands operating the trim as well as the standby ASI.

Ill post the Youtube link once it is ready.

Hi;

Yes, I'm fairly sure he means he would like the trim wheel ratio of movement vs the trim response to exactly match that of the actual airplane. This could be done but would involve a LOT of wait time in the sim. In the real aircraft the trim movement is usually a series of small hand movements on the wheel as not more than half the wheel is available to the hand (as I remember it anyway).
D

Hey Chaps

Yes I would like to have the ratio of trim to trim wheel movement as in the real plane

Kind Regards

Andrew

P.S. Oracle, I just want to be able to do what you did IRL in my Sim

[andrew737]

Hello Dudley! I don't know if Andrew is referencing the simulated trim movement ratio vs real world. I still have to try and test the behavior in the sim.

I just figured, hey why not grab the airplane and fly since wx was okay and I needed to make a run to the airport anyway to drop off a cleaned cover. I mean quit twisting my arm!!

I am uploading a completely unedited video for now, just because I'm lazy. I'll note the time of the test, but it's otherwise a full flight from start to finish. Unfortunately, the G1000 is invisible to the Gopro for whatever reason, but you can see my hands operating the trim as well as the standby ASI.

Ill post the Youtube link once it is ready.

Hi;

Yes, I'm fairly sure he means he would like the trim wheel ratio of movement vs the trim response to exactly match that of the actual airplane. This could be done but would involve a LOT of wait time in the sim. In the real aircraft the trim movement is usually a series of small hand movements on the wheel as not more than half the wheel is available to the hand (as I remember it anyway).
D

Hey Chaps

Yes I would like to have the ratio of trim to trim wheel movement as in the real plane

Kind Regards

Andrew

P.S. Oracle, I just want to be able to do what you did IRL in my Sim

Dudley am I missing something here regarding waiting time?

I have a hardware trim wheel that, with the A2A C172 as it is, trims wayyyyyy too much - If the ratio is changed why will the wait time increase?

Surley I just have to trim more (like Oracle did and I do every day) in the real plane?

Kind Regards

Andrew

[Hook]

I have a hardware trim wheel that, with the A2A C172 as it is, trims wayyyyyy too much...

There may be a way to adjust the response of your hardware trim wheel. I've never used one, mostly to avoid the problems you've described. Does it send keystrokes to the sim or is it an axis? If you tell us the make and model (if appropriate) I might be able to check the documentation and offer suggestions.

Since you're using a hardware trim wheel, there isn't any good reason to do the test I asked about earlier.

Hook

[andrew737]

I have a hardware trim wheel that, with the A2A C172 as it is, trims wayyyyyy too much...

There may be a way to adjust the response of your hardware trim wheel. I've never used one, mostly to avoid the problems you've described. Does it send keystrokes to the sim or is it an axis? If you tell us the make and model (if appropriate) I might be able to check the documentation and offer suggestions.

Since you're using a hardware trim wheel, there isn't any good reason to do the test I asked about earlier.

Hook

Hi Hook

Of Course! Its a Simkits motorised trim wheel that connects to the simulator via a simconnect interface

Kind Regards

Andrew

P.S. Ill post some pictures of the simpit on thursday...

[Hook]

Not much in the way of documentation on the Simkit site but it has a 5 turn pot so it's an axis.

Hopefully someone here might have some suggestions.

Hook

[TBryson2]

I’m jumping in a bit late here, and if I’m off the mark I apologize.

I do not know how trim wheel hardware is made, (Saitek for example) but I made my own trim wheel. The “plans” or instructions I used called for a 3/4 turn pot, much like a volume knob. Knowing this was absolutely whacked for a trim wheel, I used a 10 turn pot of the same value. My trim wheel totally behaves like the real one, (a small change in the trim yields a small change to the trim).

Is the turn ratio of “your” trim wheel whats in question here? It should (may) be possible to substitute it with the proper pot. If you’re not capable of actually doing the work, (soldering...) perhaps there is someone you know who is capable?

TB2

[Hook]

Thanks TB. Is there any special setting you have to use to get the trim wheel to work properly? And does it work with the A2A Cessna 172 correctly?

Hook

[TBryson2]

I use FSUIPC exclusively for all of my controller inputs. This does not mean it will (magically) work for you if your mechanical devices (controllers) are not physically correct. There are no “sensitivity “ settings on it that will make a 3/4 turn pot behave like a 10 turn pot. There are no settings on anything (including the sim) that will do that. The trim wheel pot is a mechanical device, so for realism you have to mimic the real thing as much as possible.

Yes, it works perfectly on all of my aircraft, not just A2A. I use it for all aircraft trims, (with the exception of some military aircraft). I still have to look “up” to watch the trim crank on the Cherokee & Comanche as I’m using the wheel to make adjustments.

You can use FSUIPC or configure the simulator to set up an “electronic” trim (using yoke or joystick buttons) and that works well, unless you need a lot of trim immediately. It’s a bit sluggish for my liking.

The beauty with a 10 turn pot is if you need a little trim, you have to move the trim wheel (say) 1/4 to 1/2 turn for small trim adjustments. But you can give it one or two full turns for more trim as you would in a real Cessna. If you have a 3/4 turn pot, it’s way too sensitive and just touching it yields too much trim. It’s not uncommon for me to use 1 to 2 turns of trim on approach. Of course, how much trim to use is all relative.

TB2

[DHenriques_]

My experience differs for the sim. I use a button assignment on the controller with a repeat slider full right. I use the same technique I would use in the real plane. I simply apply trim until the pressure neutralizes. Works like a charm.

Hi Dudley

With respect unless we all have control loading (I do and I use Brunner Elektronic Yoke & Rudder Pedals) then I cant see how we can indeed possibly trim as we do a real plane - do you use control loading Dudley?

Kind Regards

Andrew

I am set up for trim as though I have electric trim on each aircraft I fly in the sim. (Unless I am testing a new A2A aircraft that is).
I use a controller switch that acts as a pine tree trim switch.
About the only advice I can provide on your issue is to be very careful editing any files to alter how your trim behaves as Accusim is coded outside the basic sim code. There have been bad results from doing this in the past.
Wish I could be more help but this is about all I can provide really. Perhaps one of the "computer guys" can dig the issue a bit deeper for you.
DH

[Killratio]

Hello all,

Sorry, very late here too!

The *best* way to make the trim wheel respond in correct ratio to the real aircraft is to use FSUIPC. The trim wheel (assuming it has a 5 turn pot as stated earlier) can be set (calibrated) to read minimum and maximum values at ANY number of turns less than 5, thus matching the real thing if THAT is less than or equal to 5.

For example, the real Spitfire trim wheel turns for two turns either side of neutral. So setting the "middle" on a 5 turn pot is achieved by turning it full one way and then 2.5 turns to "centre", then turning it TWO turns and telling FSUIPC that is "full down" (-16250 odd ). Next four turns the other way and telling FSUIPC that is "full up" (16250 odd). Now the trim wheel matches the real thing exactly. Any movement in excess of the maximum or minimum is ignored (although running it through an idler gear can use the full 5 turns). Also, some hardware uses logarithmic pots not linear..so getting THEM to respond realistically is nigh on impossible. A simple metre test will tell you which yours has.

From Beta I can't remember the the exact number of turns the 172 has but I DO know that when I custom set my Spitfire trim wheel to THAT number it reacted exactly as the real aircraft did, the trim wheels being a not dissimilar size although feeling quite different under the hand. But the point here is that the C172 responded exactly as I would expect the real aircraft to and at the time of beta, I took several private flights in each of our 172 R's testing things like this (and FAR too much spinning!! ) to match things up. nearly 1/3 of my total hours were on Rs.

But any time that a real trim has a 3/4 turn range you will never get it to respond realistically. And if it has a 5 turn range to do a 4 turn job, likewise unless you do the above OR gear it.
The other thing to consider is the pot's quality and sensitivity. A cheap pot will not register smoothly and evenly over its full range for its full life cycle.

Now changes may have been made on an update after beta, I haven't flown the R in a while in Sim and hardly at all since beta. Trim is one of those areas that is VERY frustrating for cockpit builders when the model itself is changed to suit "simple" control set ups. 5 turn or ten turn pots with the type of calibration above is the only simple way around it, as TB2 found.



I still find this to be as relevant as the day I wrote it: viewtopic.php?f=108&t=35924&p=270879&hi ... er#p270879

regards

Darryl

[andrew737]

Oracle, Hook, Killratio, Dudley

Thank you for the contributions, Especially helpful was Oracles test and Killratio's Post - Thanks all again.

It is rather sad that the A2A software engineers have offered no support or contribution to this thread.

I suppose cockpit builders are a minority not worth bothering with!

A sincere thank you to all those who have tried to help and offered suggestions

Kind Regards

Andrew

P.S. I thought Scott might bother to offer some support

[DHenriques_]

Oracle, Hook, Killratio, Dudley

Thank you for the contributions, Especially helpful was Oracles test and Killratio's Post - Thanks all again.

It is rather sad that the A2A software engineers have offered no support or contribution to this thread.

I suppose cockpit builders are a minority not worth bothering with!

A sincere thank you to all those who have tried to help and offered suggestions

Kind Regards

Andrew

P.S. I thought Scott might bother to offer some support

That might be a bit harsh. The software team doesn't generally monitor the forums and for your specific request the available suggestions are limited as what might be required to satisfy your quest about the trim as it is most likely found outside our direct coding. As you have discovered, there are those on the forums who do "dabble" in these issues (doing changes to files.etc) and these people have tried as you have noted, to help you. My meager contribution was as always with this type of issue was to suggest that you not mess around with the Accusim files to alter the trim behavior. This didn't mean that couldn't be done; just my recommendation not to do that.
Pointing a disparaging finger at the A2A "engineers" as not being interested enough to join in on the thread is in my opinion unwarranted criticism.
This being said, I sincerely hope you and those who CAN be of help on your issue manage to be of some assistance.
Dudley Henriques

[Hook]

Hardware is outside my area of expertise. I'm glad Killratio was able to help. (Thanks, Killratio!)

Doesn't Redbird use A2A Cessna 172 software in its full cockpit simulators? There should be people around who know all about hardware interfacing.

The techies don't monitor everything on the forum. They usually monitor the tech support forums. Sometimes it takes a while before someone notices a thread.

Occasionally it happens that someone has a legitimate complaint or request and is told "you shouldn't do that." In Andrew's case it was getting his hardware trim wheel to work properly. Here's another example I was involved in and there have been others:

viewtopic.php?f=62&t=54391

Keep in mind that the techies are people too.

Dudley is right: Don't touch the config files unless you know exactly what you're doing and are willing to accept any consequences. For most people that means "don't touch the config files." A2A spends a lot of time getting things correct and balanced and you never know when some number is used in a non-standard manner or is linked to something else. I've got over four decades of development experience and have been adjusting FSX aircraft files since 2007 and I still approach them very carefully then run lots of tests on any change. A2A is the company most likely to get everything right and I've only ever made only a couple of changes to A2A files and usually document those on this forum.

A home cockpit builder's forum might be useful although I don't know how many people would use it.

Hook

[Killratio]

Well, I count at least 4 builders of full pits here (Me, Ed, Boris, a Commanche and another possible B-17 but not counting Richard Banks..he's big enough and ugly enough to look after himself ) ) and a large number of "advanced hardware users" .

viewtopic.php?f=77&t=14676&start=420

viewtopic.php?f=93&t=40795&start=450

viewtopic.php?f=29&t=22072

viewtopic.php?f=124&t=59051


Many of the AHU's run into the same types of problems we do but are further constrained by using "off the shelf" products which don't always play nice.

I can float the idea with Scott if there is interest? I'd be happy to moderate that forum.

D