F-4E Dolphin

[Adrian858]

I've had it happen twice now where I'll be flying around, then all of the sudden, this happens:

The F-4E starts doing the dolphin and the stick / stabilator become unhinged and jump back and forth.

Prior to recording this behaviour, I was at around 22,000ft and disabled the AFCS / Alt. When I was inbound on target and had jester track (context menu) the pave spike to my target, this started.

Stick deflection and Stick force blending are both unchecked.

Anyone have any thoughts or similar issues?

Edited June 20, 2024 by Adrian858

[RaisedByWolves]

Saw this one time shortly after the module was released. Have not seen it since.

[Grundar]

Porpoising occurs every so often in the F4 and I'm not sure if its a feature or a bug.  I first noticed it while flying one of the F4 missions, namely Covey-41 (which is on the Marianas map).  I was around 20000 ft and near Mach 1 and I wondered if it was a result of being in that early transonic region of flight where you are copping a mix of subsonic and supersonic airflow and the resultant drag.  I could prevent the porpoise by slightly reducing airspeed - or increasing it, reducing my trim and manually deflecting forward and then re-establishing trim.

My AI Wingman was also replicating my porpoise movements so I wasn't sure if the AI was just trying to follow some input I wasn't applying or was subject to the same situation.

So I'm not sure if it is a modeled effect of transonic flight given the right conditions - I was full of fuel and had a heavy payload or if it's a bug.  I have flown the same mission many times and it doesn't always occur.

Edit: I have stick deflection and stick blending both on. FFB is off, I don't have a FFB stick (RIP MS Sidewinder 2)

Edited June 20, 2024 by Grundar

[Tmi]

I have had this happen twice since the release. Sadly I dont have any recordings of the events nor can I remember the exact loadouts.

But on both times the oscillations started when I disabled the autopilot and descended quite fast from ~20k feet towards the ground.

[Mr_sukebe]

I haven’t seen that.

i have experienced a much slower version of vertical oscillation, which was easily solved by doing a reset using a switch just to the right of the throttle (sorry, can’t remember the name of it right now).

might be worth trying that

[Grundar]

34 minutes ago, Mr_sukebe said:

I haven’t seen that.

i have experienced a much slower version of vertical oscillation, which was easily solved by doing a reset using a switch just to the right of the throttle (sorry, can’t remember the name of it right now).

might be worth trying that

Yes the porpoising I have experienced is much less violent and is more of a gentle effect than what it is seen in that video.  Re: the switch, maybe you were using the CADC Static Pressure Compensator Correction switch?  I can't remember if I got a warning panel alert prior to the porpoise.  Perhaps there was, if it happens to me again I will capture a track for review. That all said it has happened to me twice in roughly 30 hours of flying in the phantom so it's not something I encounter often. 

I don't use autopilot so it has only ever occurred for me during manual flying, though I guess perhaps with the Stab Aug's engaged - Yaw, Pitch and Roll that the Static Pressure Compensator Correction could be related, if it effects those systems.  Perhaps I ascended to altitude too fast or descended too fast? I honestly can't recall. 

[Lau]

Had these oscillations while doing AAR and went full flaps which attenuated the effect. It seems that the longer you wait to react on it the worth it gets. Looking at your video,  it is not a speed vs GW issue, so not sure what is going on.

[Mr_sukebe]

Yep, it was the CADC switch that helped with the slow oscillations.  Might be worth a try to see if that helps.

No wonder I couldn't remember what it stood for.  What a gobfull.

[Shocktide]

I actually had this exact thing happen to me as well when using the Pave Spike too. I actually noticed it was moving the stick back and forth on the ground and ever so often during flight. Coming back into Nellis after Laser Bombing is when it really got bad. I fear this may be a bug of some sort since it did it on the ground without the plane moving. 

 

Edit: I'll try to go ahead and see if I can get this problem to replicate, I've never seen this issue occur before and this was my first time using the Pave Spike > It may have something to do with that. Personally, I thought I had maybe damaged something (Which would be odd given I try my best to be by the book) and to my suprise, I didn't. . . Plane was fine. 

 

If anybody else has issues with this or finds a way to replicate it, try and keep us posted. Thanks! 

Edited June 20, 2024 by Shocktide

[Zabuzard]

I've had it happen twice now where I'll be flying around, then all of the sudden, this happens:
The F-4E starts doing the dolphin and the stick / stabilator become unhinged and jump back and forth.

Prior to recording this behaviour, I was at around 22,000ft and disabled the AFCS / Alt. When I was inbound on target and had jester track (context menu) the pave spike to my target, this started.

Stick deflection and Stick force blending are both unchecked.

Anyone have any thoughts or similar issues?

This one smells to me like a bellows intake freeze. Especially bc u were flying so high before.

Bellows pull hard aft bc they measure abnormal pressure, the sudden high G cause the bobweights to counter and it all repeats.

In this case, pull the ARI CB (left subpanel), the TRIM and STAB CB (right wall) and disengage the AFCS and STAB systems (left console) to fly manually as much as possible. Trim neutral so that once you resolve the issue your plane isnt going to go bonkers immediately.
Push the stick forward to counter and stabilize level flight and keep it there.

Descend to hotter air and hope for the best.

Fun fact, a colleague got smacked by his FFB stick when he had a frozen bellows intake :D

[Zabuzard]

Non-violent and slow oscillations would be normal. The plane can't really be trimmed for level flight well.

In some situations the autopilot can also cause violent oscillations, but not that violent.

If you are flying at a certain speed, you can hit a sweetspot where SLATS constantly engage and retract again, causing odd dolphin movement as well. But easy to get out of by just applying stick shortly.

The last cause I have seen is our artificial code that tries to auto-trim the plane after spawn in air getting confused when you active-pause or switch to the WSO pit right after spawn.

[Dragonaut]

I've had this happen to me multiple times now, and it's always because I forgot to switch the pitot heat back on after the ground check. Once I flip it back on, it stabilizes after 10 seconds or so

[lxsapper]

22 hours ago, Zabuzard said:

Non-violent and slow oscillations would be normal. The plane can't really be trimmed for level flight well.

In some situations the autopilot can also cause violent oscillations, but not that violent.

If you are flying at a certain speed, you can hit a sweetspot where SLATS constantly engage and retract again, causing odd dolphin movement as well. But easy to get out of by just applying stick shortly.

The last cause I have seen is our artificial code that tries to auto-trim the plane after spawn in air getting confused when you active-pause or switch to the WSO pit right after spawn.


 

So the F-4 no trimming well dor level flight is actually a feature (of the simulation)?

[Zabuzard]

So the F-4 no trimming well dor level flight is actually a feature (of the simulation)?

Absolutely. The F4E was almost impossible to trim due to its unique bellows and bobweight system.

It was a sacrifice the engineers had to make. It went through 3 major revisions until the test pilots said that they are not happy with it but at least its flyable now.

On the good side, the system ensures that you naturally will roughly stay upright and neither crash into the ground or pitch up and stall just because you went heads down or blacked out for a bit. It will naturally, mechanically, always try to put the plane back to somewhat level through long oscillations.

[lxsapper]

43 minutes ago, Zabuzard said:

Absolutely. The F4E was almost impossible to trim due to its unique bellows and bobweight system.

It was a sacrifice the engineers had to make. It went through 3 major revisions until the test pilots said that they are not happy with it but at least its flyable now.

On the good side, the system ensures that you naturally will roughly stay upright and neither crash into the ground or pitch up and stall just because you went heads down or blacked out for a bit. It will naturally, mechanically, always try to put the plane back to somewhat level through long oscillations.

Cool. Thanks for the reply, and I'm sorry for the spelling errors in my post, I don't know what happened, but I just read the quote you included and I could hardly make sence of it myself! 

[Adrian858]

I've had the issue a couple more times, but very minor compared to my initial post. The Pitot heat switch mentioned by @Dragonaut immediately fixes it for me once the issue starts.

[joey45]

Something to know for future reference.. 

[FusRoPotato]

On 6/21/2024 at 1:28 PM, Zabuzard said:

Absolutely. The F4E was almost impossible to trim due to its unique bellows and bobweight system.

I have a relatively close friend who flew both Phantoms and Broncos. He described the bellows system to be like a marker. It's a lightweight reference to where center is marked for feel, but he said he generally didn't trim too often because it was easier to just plant his arms.

This reminds me of the problem with the German warbirds. How do you trim roll? It's easy. You plant your arms, or just flat out use your legs. How do you do that in DCS? There's no trim bind because the plane didn't have trim adjustment, so you have to awkwardly hold a tiny 1% angle on a stick that really doesn't want to sit there, or just wiggle your plane the entire flight making constant dramatic corrections. Well guess what, nobody flies ww2 in this sim because it sucks, because that idea sucks. You have a perfect recreation of exactly what the plane does, but no recreation of what the pilot does that the human user at his desk with his cheap ballsocket joystick can't.

For the F-4, it still seems like there's a general lack of pilot response modelling here, especially around stick center. Keep in mind: Most people are using hardware that has a strong center return, a deadzone, does not come up between their legs (their elbows hang or can't be planted/braced/anchored), and does not have force feedback. Physical responses with FFB are almost instantaneous because the arm and stick have to be physically accelerated. Additionally, our mental response to physical stimuli is typically several times better than reacting to what we see. Learning a response frequency by sight is extremely difficult relative to learning it by feel.

This is almost perfect with expensive hardware but not with basic stuff. If I wiggle a stick without FFB just a tiny amount, but at just the right frequency, I can get the virtual stick in game to flail around quite violently. How is that reproducible in real life?

You should really consider options that compensate for a lack of advanced setups similar to the force blending and max stick force options.

Edited July 13, 2024 by FusRoPotato

[kablamoman]

Seems to illustrate, once again, the problem of decoupling primary controls from pilot input in the manner that they've done with this module for non-FFB joysticks.

Some kind of bellows blockage may be being simulated quite accurately in terms of how the feel force is being dynamically altered, but with that feedback sent into the control loop as a layer of stick deflection changes (and thus stab deflection changes) and the pilot being unable to directly interface with the pitch channel in a manner that can override or damp said feedback, the results as posted by OP speak for themselves.

Here's the Emergency procedure taken from the flight manual, for reference. Good luck with number 5.

11 hours ago, FusRoPotato said:

Well guess what, nobody flies ww2 in this sim because it sucks, because that idea sucks.

Generally agree with you, but I think this statement is a bit of a non sequitur. People don't fly it for other reasons related to asset and DLC requirements, and a general lack of cohesion with the timeframe and assets in the face of pretty strong competition from another title that does those things particularly well. The warbird stuff is generally praised in terms of flight modelling, with very few exceptions (compared to that same competitor). There are a few cases like the aileron/stick center issue with the German birds that I would say come about primarily due to the limitations of modern input peripherals, as you said. Rather than try to alleviate the problem by implementing questionable modeling in software (which introduces its own set of problems, as we've seen with the F-4), they've retained the integrity of the control loop. I fly WW2 more than anything else and would characterize your example as pretty minor in terms of its actual impact when flying, while still acknowledging you're technically 100% correct about it being a real limitation in the sim's interface with home hardware. The real solution is of course FFB that can recenter your real-world stick dynamically and as appropriate.

Edited July 13, 2024 by kablamoman

[FusRoPotato]

6 hours ago, kablamoman said:

Generally agree with you, but I think this statement is a bit of a non sequitur....

...I fly WW2 more than anything else and would characterize your example as pretty minor in terms of its actual impact when flying, while still acknowledging you're technically 100% correct about it being a real limitation in the sim's interface with home hardware. The real solution is of course FFB that can recenter your real-world stick dynamically and as appropriate...

...There are a few cases like the aileron/stick center issue with the German birds that I would say come about primarily due to the limitations of modern input peripherals,

 

It's not really a non-sequitur. Relative to other sims, nobody flies DCS WW2. The dozens of us don't count, and just because I blame one reason doesn't mean there aren't many more. The WW2 implements within DCS lack a large degree of quality found in sims that are typically considered lower fidelity, like tail-slide center-of-lift shifting, torque, spiraling vortex, gyroscopic and p-factor moment effects, and/or low-speed tail-wheel caster stability mistakes. During a slide, we get this assumed perfect continuous laminar flow effect over the tail no matter how fast we're sliding and just get somewhat stuck, nose up, without any presence of torque spin. The call that implementation. Some of the DCS modules didn't even feature fake scripted versions of the effects for most of their existence like the T-51 and yak. At best they just perform a little wiggle. The evidence of hackery, magical dampers, and mystery coefs used in their methods to fake some of these effects are all throughout their lua files and paint a pretty strong picture of how underdeveloped the WW2 FMs are. Sometimes people who throw praise around are just having a wank. The proof is in the community involvement. You won't convince me people don't play around with it just because it's era inaccurate or costs $100 to get into. Go tell that to a Warthunder player.

However, the analogy was intended to target the importance of things that matter. On one hand you can skip a lot of high fidelity components and still have a strong and satisfying representation of a plane's nature and legacy, but if you only go halfway and skip considerations for human-to-hardware interactions, you can get the potential for a worse outcome through a higher offering of fidelity. I think this is why so many people walk away from choppers until they get their pedals. We're not talking about limitations of modern peripherals. If there's no way to setup reasonable controlability without expensive hardware or some kind of elaborate vjoy scripting, then the module/sim itself has a design problem and people walk away.

Edited July 13, 2024 by FusRoPotato

[kablamoman]

On 7/13/2024 at 3:00 PM, FusRoPotato said:

The WW2 implements within DCS lack a large degree of quality found in sims that are typically considered lower fidelity, like tail-slide center-of-lift shifting, torque, spiraling vortex, gyroscopic and p-factor moment effects, and/or low-speed tail-wheel caster stability mistakes. During a slide, we get this assumed perfect continuous laminar flow effect over the tail no matter how fast we're sliding and just get somewhat stuck, nose up, without any presence of torque spin. The call that implementation.

Disagree with a lot of this, but not really the forum section to dig deep. Suffice to say that I would contend torque, gyroscopic and p-factor effects are there in spades (especially compared to the other sim). Prop wash is also present, with the ability to raise the tail off the ground at high power even when stationary on the ground. Whether these are hacked in effects, or part of a more robust simulation, I do not know. Ground handling itself is also much better than other titles, although I have some reservations about the spongy oleos in the new P-51 suspension implementation. I do acknowledge that it doesn't seem like control reversal with airflow reversal in a tail slide is modeled much, if at all, but you absolutely do spin like a top once you're near zero airspeed in a prop hang. I also question the lack of adverse yaw modelled in many of the warbirds (though it seems very present in the P-47).

If you do have some input about the FMs, I think it would be great to post in the WW2 forum. I would love to see Yo-Yo address the handling in the tail slide, personally, and would find it very interesting if he engaged on some of the other points you mentioned.

I really do think the comment about the FM is a non sequitur. Almost universally, other issues unrelated to the flight modelling are cited as reasons for preferring other titles. It is generally acknowledged, even by hardcore fans of the other sim, that the DCS warbird FMs are modelled with a much greater degree of fidelity and accuracy. With a fair bit of real-world experience flying, I certainly feel DCS' warbird offerings are modelled much more accurately than its main competitor (though as with any other internet random, feel free to take that opinion with a grain of salt).

Edited July 16, 2024 by kablamoman

[=475FG= Dawger]

 

On 7/13/2024 at 1:21 AM, FusRoPotato said:

 

This is almost perfect with expensive hardware but not with basic stuff. If I wiggle a stick without FFB just a tiny amount, but at just the right frequency, I can get the virtual stick in game to flail around quite violently. How is that reproducible in real life?

You should really consider options that compensate for a lack of advanced setups similar to the force blending and max stick force options.

 

Damned if you do, Damned if you don't.

ED's F-5E has absolutely no modeling of the artificial feel system for the pilot, resulting in the ability to generate instant 13 G and subsequent catastrophic failure and the general community response is "git gud". Hardware setup doesn't matter much and flying it like a real airplane will kill you, so you have to learn to "game" the module.

HB at least tried to model the system actually used in the Phantom to provide feedback to the pilot. Yes, this system does require a higher level of hardware to appreciate fully or even partially but that is the price of admission. Maybe they should add some peripheral hardware recommendations for the module. 

So I say, invest in floor mounted stick with a 20 cm extension at a minimum or FFB for the ultimate experience or don't get/fly the Phantom.

Don't ask HB to dumb it down for folks trying to fly on an Atari joystick.

[kablamoman]

15 hours ago, =475FG= Dawger said:

So I say, invest in floor mounted stick with a 20 cm extension at a minimum or FFB for the ultimate experience or don't get/fly the Phantom.

Don't ask HB to dumb it down for folks trying to fly on an Atari

I have a center-mounted 20cm extension already but without FFB the F-4 stick simulation Heatblur has given us is completely broken. As others have pointed out quite accurately it behaves as if we are not interfacing with the control column at the stick, but as if we are reaching through the floor and applying force at some point behind the spring that couples the trim actuator to the stick.

I am not necessarily against adding stick weight limits to total deflection or rate of deflection (as the 47 and 109 already model) and definitely agree that the F-5 wing snapping debacle was a problem. Those particular elements of the F-4 implementation I do not have a problem with (although I would prefer to fly without the stick force blending option, which when active, behaves somewhat similarly to IL-2).

The problem is the assumption that a centered spring stick ends up meaning no grip at all. The stab is free to oscillate all over the place.

I have got my name on the list for a Rhino and will look forward to trying other FFB hardware as well once they hit the market, but for now the non-FFB implementation of the stick in the F-4E is problematic at best, downright broken at worst (in my opinion).

Edited July 17, 2024 by kablamoman

[FusRoPotato]

10 hours ago, =475FG= Dawger said:

Maybe they should add some peripheral hardware recommendations for the module.

Why would people want to buy a module that requires more expensive hardware? Why not just make the module optionally more compatible/usable with a standard joysticks?

[Schlomo1933]

Am 17.7.2024 um 04:18 schrieb FusRoPotato:

Why would people want to buy a module that requires more expensive hardware? Why not just make the module optionally more compatible/usable with a standard joysticks?

Because the immersion and the feeling of flying gets 1000% better with good hardware. 
I’m using since a year a 
Rhino FFB stick…. And flying the F4, F14, helos  or warbirds is an entirely new World of feeling and immersion. 

 

Edited July 18, 2024 by Schlomo1933