fat creason

If anyone can provide track files or videos of any ordinance being released at constant power and level flight that would be appreciated. We need to gather examples of this happening.

https://forums.eagle.ru/showpost.php?p=3980929&postcount=20 TLDR: We think something strange is going on with stores drag or gross weight on the DCS side but we’re not entirely sure. We're working with ED to get to the bottom of it.

The FM is in an overall good spot, with the exception of a few areas that are currently being worked on. We stand by what was said at release, but please do not forget that it is also early access and we are still fine tuning based on SME feedback. The entire basis of the FM comes from very accurate wind tunnel data that got us 90% of the way there, but the Tomcat is a very complex FM that still requires a large amount of work to get right, especially in the handling qualities area to which SME feedback is critical. We use an FM testing system that resides entirely outside of DCS. We use this testing system to give us feedback on changes to the FM using tests derived from the F-14A+ performance manual. We like to test as close to a “clean” aircraft as possible since we don’t have much control over stores drag in DCS. The manual’s lowest drag configuration is a 4xAIM7, 4xAIM9, no tanks loadout. For these tests we use hardcoded stores drag data that was provided to us by ED during initial FM development. Additionally, these tests are mostly static tests or tests related to aspects of aircraft performance in specific areas of the flight envelope. These tests run every time we make a commit, and the results have been largely unchanged since EA release with the exception of a few which I will address for transparency’s sake. At release we felt (and tests indicated) that we were slightly overpowered in level flight acceleration. In response to this we made even more FM tests against specific excess power across the entire maneuvering envelope. These new tests indicated we were massively overpowered, so I reduced engine thrust operating on the assumption that the drag data from the wind tunnel was correct (we still believe this). The result was an underpowered engine for 1-2 patches while we tried to figure out what was wrong with the excess power tests and why they disagreed with the level flight acceleration tests (both of these sets of tests essentially test the same thing in different ways, and we cross-check them with in-game handflown testing, too). I ultimately ignored the excess power tests and started the development of a new more advanced testing system which I am still working on, which brings us to now. The FM performance is more or less back where it was at EA release according to our current FM test system. Unfortunately, the entire FM’s foundation actually rests upon the shifting sands that are DCS, not our external FM test system. The interface between our FM code and DCS physics is primarily only forces and moments. DCS handles the equations of motion as well as a few other significant areas, including: Aircraft gross weight and mass properties (we only have control over empty weight). An incorrect gross weight calculation will seriously affect performance. DCS handles all aircraft mass properties beyond just the empty weight. External forces and moments. Think the forces and moments generated by interactions with the ground via landing gear or airframe contact, or even contact with other objects. All of the non-aerodynamic forces and moments applied to the aircraft. Stores drag. DCS provides the forces and moments generated by stores drag. We have little insight or control over these forces and moments. Atmosphere model. DCS provides temperatures, pressures, and density at the ownship used for all aerodynamic calculations. This ultimately means that if any of the above areas have changed, these changes are no longer reflected in our FM testing environment. If something on the DCS side has changed that now affects the Tomcat’s performance in-game, we have no real way of knowing short of ED telling us what changed or catching it while hand-testing in game. We suspect some things have changed and other things may be inaccurate, but we’re not sure what. We’re working with ED to try and solve these issues. For people who perceive an in-game FM performance loss, our FM tests have not indicated any loss in performance over the past month. If anything, the Tomcat's performance has only been increased in the past 4-6 weeks based on intentional FM changes I’ve made that the testing reflects. Future work There are a few outstanding FM items I want to address, beyond normal maintenance that will pop up: Subjective handling qualities: Flaps, Gear, Speedbrake pitch moment and drag effects. Working to better tune these based on SME feedback. Misc handling accuracy improvements, all minor and on the edge of the envelope. Performance: Tune for specific excess power across the whole envelope. It’s close, but definitely needs more investigation and better testing. Tune performance of slats and flaps while using maneuver flaps. As you can see this list is not very long, but many items are just time consuming. Tuning the handling qualities is very time consuming, as it has to be done by hand-flying in DCS and is hand-verified by SMEs since no handling qualities tests are available for the Tomcat. Some aspects of performance are more easily verified by automated tests and tuning can be done more quickly, assuming the tests are good. Once we think the FM is as “done” as it can possibly be, I’ll make an FM status post.

Well that's...interesting. Could be related; but if it is, it would be affecting more than the tomcat FM.

Our FM tests have not indicated any loss in performance or aircraft drag changes over the past month. These tests run within our own testing framework and not DCS, so newer changes to DCS may not be reflected in our testing environment. If anything, the Tomcat's performance has only been increased in the past 4-6 weeks. We're investigating and working with ED to figure out what's going on, as it certainly seems to fly with decreased performance in-game all of a sudden. The interface between our FM code and DCS physics is mainly forces and moments, not including the forces/moments from ground reactions and stores. We have very limited control over those two areas as they are calculated by DCS before it all goes into the equations of motion. We have a few theories as to what's going on, since our testing framework may not be in sync with potential ED changes to the areas mentioned above: 1. Gross weight is somehow not being calculated properly when fuel/stores weight changes. 2. Stores drag model needs more investigation, with certain loadouts/configurations we suspect there are drag discrepancies. If gross weight is higher than it should be on the DCS side of the fence, the aircraft will need to fly at a higher AoA and airspeed to generate enough lift, resulting in more drag and more power needed. Right now we're seeing lower climb rates in-game as well as sluggish acceleration in BFM and too much power needed around the boat in certain stores/fuel configurations. This could be related to weight, drag, or both, but it's hard to tell since everything looks unchanged in our testing environment. Once we can get a response from ED we will provide an update.

Can anyone provide a step by step way to reproduce this bug that works every time, without fail? It would make this much easier to track down as it’s never happened to me.

https://forums.eagle.ru/showpost.php?p=3914367&postcount=19

Just tested my fix, should in the next patch. You can now engage AP as long as the FFB stick is at the trim (zero applied force) point.

Looking into a solution for FFB and engaging AP right now...

This is incorrect. The F110 nozzle is actuated hydraulically by engine oil pressure in each respective engine. My understanding from our SMEs is that when oil pressure drops, the nozzles will generally move to the closed position unless blown open by the exhaust. There will be a fix for this coming soon. See this post below for more details: https://forums.eagle.ru/showpost.php?p=3912300&postcount=17 The TF30 nozzles are actuated hydraulically via fuel pressure instead of engine oil pressure. The operation of either system has nothing to do with the hydraulic system of the aircraft.

I discussed the nozzle issue with one of our SMEs, according to them the F110 nozzles generally close when oil pressure needed to actuate them drops below a certain amount. When the AFTC comes online at 59% RPM in PRI mode, the nozzle opens as the engine spools up. At idle, the throttle should keep the nozzle open if AFTC remains in PRI mode. In some cases it may blow open if oil pressure fails. I may add that eventually but for now the nozzles close on oil pressure loss. F110: The TF30 nozzles are actuated via fuel pressure. They seem to stay in position or blow open if fuel pressure is lost in the AB fuel pump. TF30:

We are currently undergoing some thrust and drag tuning based on a new battery of FM tests we created. The tests were indicating we were overpowered but we quickly realized some of these tests were misleading in terms of specific excess power measurements. Increased thrust is coming as part of these ongoing changes as we get the model to match the excess power charts all the way from 1G flight up to 6.5G maneuvering flight. Sometimes the iterative approach required to tune FMs causes things to get worse before they get better. Look for some handling qualities tweaks in the future as well. I’ll make a post detailing these changes when they’re complete.

As Cobra stated, we’re in the middle of making some FM updates based on a new large subset of automated tests we’ve recently created. These tests will help us match the data even closer than before. I plan on making a post detailing these updates once they’re complete. Beyond that you may see some subjective handling qualities tweaks based on SME feedback, but nothing else is anticipated that will affect raw performance numbers. Ideally, we would like to have the FM’s objective performance numbers with the F110 as close as possible to our data sources before working on the TF30 thrust model. Changes in lift and drag will affect performance that usually results in needed changes to thrust, and we’re trying to avoid having to change both thrust models later down the line. Essentially we want to eliminate the airframe itself as a source of error before we’re having to maintain two thrust models on the same airframe. Hold your sticks and whip out your EM charts after I’ve made the update.

In the times I’ve sat down to try and reproduce this bug I’ve been unable to do it. Unfortunately it takes a lot of time to test and I’ve got other larger things on my plate at the moment. Hopefully one day it’ll happen and I can find out why.

You probably induced supersonic inlet buzz, try going subsonic to clear it. General rule of thumb when having engine trouble is to slow down to subsonic speeds/take the engine out of AB, and then try to assess the situation.

The inlet ramps do indeed work, and they influence the amount and quality of airflow entering the engine among other things. We are matching level acceleration according to automated flight tests taken from the performance manual. Variances in OAT do affect the amount of power the engine can produce due to changing air density with temperature.

If you’re touching down at 200 KIAS and you immediately yank the stick back it should be no surprise that it results in a touch and go. I’m surprised that you can even get it to touch down at that speed while in ground effect unless you’re practically flying it into the ground. Land at 15 units AOA with the flaps down and ease the stick aft on landing rollout below 100 KIAS. This will provide aerodynamic braking from the stabs. You can also use lateral stick to maintain centerline via differential stab, but keep the stick aft while doing this.

Try swapping FF axes under FF tune. DCS sometimes likes to randomly swap the axes for no apparent reason.

Indeed. Wanna build me something?

Very hard to tell from your description what exactly is going on. Are you entering a tail slide? Either way, sounds like you’re on the edge of the envelope at low airspeed where internal forces dominate.

Once the list of high priority bugs on my plate starts to drop I’ll begin work on the TF30. The Tomcat has been out for less than three weeks, be patient.

Edge cases are still being tuned for thrust. I do this in my free time so it’ll be a few update cycles before I’ll be happy with it.

No consumer level spring stick or FFB device can come anywhere close to replicating the amount of force required to move the controls of real aircraft.

The next update will have stronger spring forces and more closely replicate the Tomcat’s feel system which is essentially just some springs, cams, bobweights, and the trim actuators. The roll axis will be lighter than the pitch of course, but not as weak as current. The main issue is the lack of documentation regarding the arbitrary values I’m sending to the FFB API.

I use a VKB MCG as my primary stick mainly because of the extra buttons it provides and the gimbal is decent. Would definitely use a FFB stick if a nicer one came out.