Spitfire trim improvement

[=CfC=Bounder]

The reluctance of everyone to fly the new Spitfire FM in 4.10 due to its instability and trim effects prompted me to try and find out if a completely revised set of trim characteristics built into a joystick profile and tailored for the Spitfire would achieve any results.

I’m delighted to report that it is significantly better to the extent that I will now definitely try and fight with it.

The way I set about things was to play Team D at their own game. In other words they have published pictures showing elevator position in flight IRL and talked about realism etc. So this is what I did.

- Open QMB and select the Spitfire version that you like most and fly the most online. I chose a late 1941 Spit VB to start things off.

- On the arming screen, you can select a joystick profile. The profile that you are currently flying is the one that is shown. In my case I was using profile 3.

- To cut this description down to the finished profile, I will give you the settings that I finished up with that work well with all the Spitfire variants.

- So, with profile 3 showing, this is the one I use for all fighters under normal circumstances, I selected the “rudder trim” and changed it (after several experiments) to “35” all the way across (straight line with 35 in all 10 stations). This gives a much reduced maximum trim input but makes it suit the Spitfire sensitivity. Remember, that TD have to provide trim requirements for a number of different a/c including twins with one engine shut down. What the Spitfire requires IRL is what I have settled with. You now apply “maximum right” rudder trim for T/O (this allows for WEP on the Seafire T/O also). This is the only time you will need maximum trim and as the speed increases you will end up with zero trim eventually. This together with the use of the tail wheel lock provides an almost hands free T/O when used with zero elevator trim. Using this set of trim settings now enables a much more subtle trim input and in general far less trimming.

- For the elevator trim, I also reduced the sensitivity at the zero trim end. In addition I reduced the total trim up entry to give stable in trim handling with approach power (25-30%) and fully configured (gear and flaps down) at 1.3VS (1.3xstall speed). For this variant this gives you 85-90 IAS stick free (hands off) in the landing config. The settings for the ten “elevator trim” entries are:- 40 45 50 55 60 65 70 75 80 85.

- Having made these changes, I changed the “joystick profile” number to “4” and pressed “Save”. So my Spitfire profile will always be available by “loading” profile 4.

- Interestingly, these settings work well for all the Spitfire variants and now they appear much easier to fly. The full up elevator trim settings also seem to adjust themselves for the various approach speeds of the different variants. For example, with the trim set fully up in the approach config., the Seafire settles down at around 80 IAS and the 25lbs variant at 90.

- Combat with the Spit unlike 4.09 now requires zero elevator trim which gives you a slight pitch up tendency whereas before you had to trim nose-up.

You might like to give this a try and come out with your own reduced trim settings….they definitely help.

Bounder

[=CfC=Palmtree]

Fantastic Bounder!

Definitely makes a big difference!

[CFC_Conky]

Cool Bounder, how do those settings work with other aircraft?

Pip, pip,
Conky

[=CfC=Doc]

4.10 offers the ability to save multiple joystick profiles. Because of this, other aircraft are not an issue.

[=CfC=Bounder]

As Doc says, you can have up to 4 profiles now within 4.10.

If you use JoyControl, the saved profiles in 4.10 will override these settings although you will still find them in your conf.ini. Best to keep one profile that you have been using and experiment with the other three that are now available.

Incidentally, I have not changed the elevator/aileron/rudder profiles from what I had before...only the trim profiles that are for the first time adjustable within the IL-2 prog. I get the impression that they may have changed the basics for trim in 4.10 which therefore may affect flying a number of different a/c.

Having reduced the rudder trim input to almost 1/3 of the max (setting 35 in all boxes) seems to work well with all the single engine a/c. Most of the big singles IRL required a large input for take-off and this setting makes it easy as you can wind in full rudder trim for all the big singles and wind it off at climb speed. Since the input is reduced to 1/3, this change is much more manageable and results in fewer oscillations.

I'm now going through all the different a/c and also flying the same profile in UP 2.01 with pretty good results. Only a/c that seem to require more trim are the suspect FM's like the pitch FM in the B17, but that requires work from the modellers so I have a feeling that I will settle for these trim settings for both 4.10 and UP 2.01 to keep things simple and not get too many shocks when changing from one to the other.

Bounder

[CFC_Conky]

Sounds good Bounder, I forgot to ask though, are you using a control axis for your trim? I have mine mapped to switches on my controllers. Reducing the trim sensitivity makes a lot of sense, irl trimming is much more subtle than in-game pre-4.10.

Pip, pip,
Conky

[=CfC=Father Ted]

Top work Wilkins, I mean Bounder!  Is there any hope for those of us who don't possess controller axes?

Ted

[=CfC=Bounder]

I have an X-52 Pro which is very fortunate as it has trim wheels for elevator and rudder trim...however before that I had the trims assigned to the "arrow" keys.

In theory, if you reduce the trim settings as in my thread above, each time you press the key assigned to a trim, a much smaller input should result.
I can only sugest that you experiment in trying to reduce the overall trim applied by looking at the diagram of red and green trim input within the jouystick setting screen in 4.10 whilst pressing whatever key you have assigned (after setting 35 in all boxes)

I hope it works for you as I'm finding it a lot easier to fly with these settings.

Bounder

[=CfC=BlueDog]

I'm not sure "trim" is the right term here.   Unless I'm mistaken (which is entirely likely anyway), you are actually setting control deflection using the "sliders".   This is the same as it's always been in IL2; except that now you can set up to 4 different control profiles.

What you end up with as far as response to controls is concerned is all very subjective.   The reason it's there is to provide the individual the ability to tailor aircraft response to controls to his particular taste.   eg. for elevator/aileron some like to have 100 across the board, others like low settings from 0 working up to 100 in all manner of ways.   Personally for elevator I like 46, 52, 58, 64, 70, 76, 82, 88, 94, 100 and for aileron 55, 60, 65, 70, 75, 80, 85, 90, 95, 100.   For rudder I use 10, 20, 30, 40, 50, 60, 70, 80, 90, 100.
 
What is important is that the figure not only determines the degree of control deflection but it also determines the rate of deflection.   Consider the following:

1.   You cannot increase the amount of control surface deflection past it’s nominal maximum at a particular point; but you can limit the deflection to less than the nominal maximum.   In explanation, let’s say slider 5 gives 50% of full control surface deflection and that deflection is available with 50 set as the slider value.   If you then set 100 as the slider value, you will still only get 50% of full control surface deflection.   If you set 20 as the slider value you will get significantly less, (say 20%) of full control surface deflection.

2.   The rate of travel of the control surface can be increased or decreased by adjusting the sliders.   In the above example, with 50 set, the control will travel at a moderate rate, with 100 set it will travel faster (at maximum rate) and with 20 set it will move slower â€" and be limited in the amount of travel.

The thing that you need to consider in the case of the Spit settings set out here is that you are limiting the upper end of elevator control deflection to 85% of full deflection.   This may not matter all that much in normal flight or in combat at higher speeds, but if you need to have full available deflection at slow speed or in (say) low speed scissors you will not be able to get it.   The up-side is that you will probably have a better chance of avoiding the dynamic stall.

Also you are limiting rudder deflection to 35% of full deflection.

What it comes down to, though, is that if it suits you, then that's good.   Stick with it.

[=CfC=Bounder]

BD,

Open your new "joystick" control GUI from the arming screen in 4.10 and you will see that you now have the ability to change the "Trim" profile for rudder and elevator.

All the above discussions are related to the new "trim" settings and not the overall displacement of the control surface which is set in "Elevator" and "rudder" GUI entries.

This trim setting only affects what happens when you move a "trim" wheel and has no effect on overall control surface movement. It is the same as using the facility in "JoyControl" for trim, only now you have the ability in 4.10 to save 4 different profiles and because of the way they have implemented trim for the Spitfire, you definitely need to reduce the sensitivity of the "trim", not the overall control input.

Bounder

[=CfC=BlueDog]

Hmmm........I don't seem to have a "trim" function.   I have E/A/R as well as (new) power, brakes & prop pitch. 

If I select "elevator", for example, I can move the trimwheel and see the movement on the green/red displacement thingie.   By setting the sliders so that 85 is the last number I can see that I am limiting 'trim', but when I move the stick I find that it is also limited to less than full available deflection.   

I don't believe trimmers are actually modelled in IL2.   Trimming is achieved (simulated) by moving the control surface itself.

[=CfC=Bounder]

That's odd. You must have 4.10 BD. All this only applies to the new 4.10. Only other thing is maybe your CH profile is not mapping trim from within IL-2 4.10

If you have it, open a QMB mission and go to the arming screen. At the bottom of the screen is a button "Joystick".

When you open this GUI on my install, you can select "elevator trim" or "rudder trim". You can then try the settings that I have found help a lot with stability especially flying the Spitfire with the new FM. If you don't see this, you can always set it in JoyControl.

You are right, trim just re-centres the control surface, but these settings have no impact on the overall limits on control surface movement. They just de-sensitise the trim input which is necessary now for the Spitfire FM.

Example.........your "rudder" settings will govern how far your rudder will move. Most people will have 100 as the last entry in their rudder profile to get full rudder control surface movement.

Example.........your new "rudder trim" settings, only available in 4.10 (or in JoyControl for other installs) can be set as I have suggested to 35 in all boxes. Now, when you move your trim wheel, the surface will move to trim out the forces only about one third of the travel than would have occurred by leaving the "rudder trim" settings to 100. This avoids severe lateral oscillations in the new Spitfire FM when trying to trim and also approximates the trim input that the Spitfire had IRL, i.e full right rudder trim for take-off. (Merlin-not Griffin)

Maybe the X52 is supported now in 4.10....I really don't know! I had not realised that stick software may impact your ability to set this in the new 4.10 installation.

It may be that you find the trim for the Spitfire in 4.10 acceptable, but judging by the entries on the Ubi Zoo and also at 1C, most people are finding the lateral trim impossible to get on with in its default setting.

Bounder

Here is what my entry looks like. I have set my trim wheel to full right trim and the green square shows that the maximum surface movement in "trim" mode is about one third of the red square which shows the maximum movement of the wheel. When I select my "rudder" profile, I still get maximum rudder deflection shown by the green square at full deflection and the red square underneath.

[=CfC=Palmtree]

You have to assign a rotary to a trim function under the HOTAS settings and then it shows up in the drop down menu.

Now I understand the best elevator trim setting for the Spit, I have gone back to using hat switches and after setting elevator trim I can successfully set the rudder trim to eliminate most side slip. I cannot eliminate the lateral roll but it is now reduced somewhat.

[=CfC=BlueDog]

You have to assign a rotary to a trim function under the HOTAS settings and then it shows up in the drop down menu.

Ah, there's the answer, thanks PT.   I have mine set to switches on my CH gear.