Engine Response to throttle input?

I'd say almost the opposite, they feel very sensitive. I find it difficult to maintain a speed without constantly moving the throttle tiny steps. I tried AAR for the first time today and it's the same, constantly moving the throttle to maintain desired speed. The tiniest increments I can do gives me big(5-10+ knots) changes in speed.

I watched a few videos from real life approaches in the F-18, the throttle never stops moving.

Link?

https://forums.eagle.ru/showthread.php?t=210579

Read the whole thing when you have time. There are some good posts from others too.

The bad weather recovery video is from a Superhornet.. But otherwise, I agree that something in either the drag, FCS, engine power models or a combination of them, or something else, is off.

https://forums.eagle.ru/showthread.php?t=210579

 

Read the whole thing when you have time. There are some good posts from others too.

^ +1

Grab some popcorn and read through the above thread. Answered some of my questions/concerns on the Hornet early access, WIP.

Cheers,

I feel that what’s missing is the plane needs to have some more weight to it. It almost acts as if it has very little inertia. Plane is 33,000lbs on landing and if u cut power at all you lose a lot of airspeed. Seems like there’s a lot of drag modeling from flaps but that the plane responds too fast for its weight.

Also I think people get behind on the power curve and expect the plane to just speed right back up. It can’t dragging the gear and full flaps with very little intake pressure. Wing also has to get out of a stall and have clean airflow.

This is why you never wanna get on the wrong side of the power curve.

I also think a lot of it is due to not being able to feel the stick pressure and aircraft in the sim. Friend of mine is an F16 Pilot and plays hell landing in sims. It’s just all visual where real life you fly by seat of your pants. Carrier Traps make this even more difficult.

I found that the throttle response is alot quicker then before.

exactly, after the laast 2 patches is more responsive than before, let's say we have less turbo-lag now :thumbup:

exactly, after the laast 2 patches is more responsive than before, let's say we have less turbo-lag now :thumbup:

It's still noticeable more sluggish than even civil jet-engines (apart from the real large fan engines like the PW4000).

Especially in the higher RPM regime, e.g. above 80% there is almost no lag when increasing/decreasing thrust IRL. RPM response should be instant.

This present sluggishness makes fine corrections rather difficult during the approach.

The acceleration from idle to mil takes ~4sec and the acceleration from 80%-90% requires almost the same time which is much slower than any jet engine I've ever operated IRL.

The Heatblur Viggen seems to have a realistic spool behaviour, especially in the above mentioned RPM range.

Feel free to do your own testing. I made a thread and to me the F404 is not spooling quick enough. GEs documentation shows under four secs from idle to 100% and we are about 2 seconds slower then that. One of the docs even shows and average in the low 3 second range.

https://forums.eagle.ru/showthread.php?t=217200

The problem in the current version is drag modelling, Gear drag modelling is almost there and was responsible for a lot of the extra drag as it was definitely too high. Tuning everything is a complex process, as changing one thing affects another, but ED are doing a great job getting there. The AoA stability is also another thing being looked at.

The way this translates right now is that you are fighting the drag with very high throttle settings and just a very small reduction from the ideal setting results in a larger than normal rates of descent and VV movement. As a result throttle movements have to be constantly on and off around the ideal setting as the 'sweet spot' as its been called is too difficult to find accurately.

In short, it's going to get easier so don't lose heart if your struggling a little now. At the end of the day it's all good fun and what you learn now will stand you in good stead.

My own 404 research shows 4 secs from idle to Mil (about right for this type of engine) & my tests show that's correct within a nats c*ck. The time taken to accelerate from say 80 to 88 is no different than from 88 to 96. By all means post videos with on screen timers to correct me. I shalln't delve into high bypass versus low bypass jet engine spool times as there is a myriad of info on net there ready for googleFu 'ing.

The time taken to accelerate from say 80 to 88 is no different than from 88 to 96. By all means post videos with on screen timers to correct me.

I don't care much if the slam acceleration from idle to mil is off by a second. I'm just pointing out that a jet engine generally reacts faster in the high RPM range. The acceleration from 80-88 is as wrong as it is from 88-96 IMO.

It doesn't make any sense why the engine needs to accelerate from 88-96% in the same timespan as from idle to mil.

If you advance the throttle the thrust/RPM increase is almost immediate and there's usually not a 3sec delay to achieve the desired thrust.

Here are a few examples where you can see/hear how fast the engines are spooling up and down. (the Pegasus engine isn't exactly known for it's fast acceleration)

https://youtu.be/aUifhhPLxpU?t=218

Presently you can't really use a quick throttle burst to make small corrections like in the above videos, because instead of a short, less than a second throttle burst, the engines require too much time to spool up and down again be able to use this correction method.

Another strange behavior is that the acceleration starts to slow down a few % before reaching the desired setting.

Nevertheless, if it's drag, pitch stability, spool rate, that are WIP, it's in its present state already a truly magnificent add on that's incredible fun to fly :) :thumbup:

The hornet engines as currently modelled make the A-10 seem quick to respond.

According to some vids i've seen of the A-10, the fan in DCS A-10 has way too little inertia, and it is what provides most of the thrust. So the issue is rather that the A-10 engines are way too quick to respond to throttle changes, the F-18 is probably in the right ballpark.

I am not a real jet pilot, but I play one on my PC. With that disclaimer I agree that the throttle seems sensitive enough. Apparent "sluggishness" is likely due to the inertia of the 16 ton mass of the aircraft. Response not dissimilar from VRS F/A-18E. Watch airspeed. You will see it changing before the E bracket starts moving. I find that many hours of practice are required to attain the muscle memory and anticipation needed to prevent constant throttle over-correction. I am still learning, but improving in that area. Acquiring that muscle-memory can be hampered by too frequent adjustment of the throttle thrust curve, so I recommend minimizing that action. Set it and forget it.

I feel the throttle is weird too. PRior to this I had been flyinf Jan'es F/A-18 from 1999-2006 and then I was flying VRS' Super Bug extensively before the DCS Hornet came out. In the DCS Hornet, I find myself throwing in like 25% or more thrust to maintain AOA and GS. I find that all trimmed up and full flaps, my throttle is in the upper 75%, and more often in mil thrust or sometimes even afterburner. In VRS' Super Bug I never had that much throw in the throttle and I could do small power corrections rather than 25% power corrections in the DCS version. I dunno, it seems odd...

In a related matter, I HIGHLY recommend viewing Jar113's third Youtube video on Case 1 recoveries. His explanation of trimming to on-AOA finally turned on the light-bulb for me. You will learn that in proper recovery technique the stick is used ONLY to control bank angle and use ONLY the left hand to control pitch. Call the ball.

 

 

 

https://www.youtube.com/watch?v=Xso1mMo_1Mg

I higly agree. You should be trimmed up enough to not need any kind of back pressure on the tstick and only use it to correct for lineup. All the main corrections should lie in the throttle.

Now if they can just get it so that you can see the ball BEFORE the rounddown, that would be great. If they can't, then maybe put a magnified version in the bottom center of the screen like JF18 used to.

v6.

boNes

According to some vids i've seen of the A-10, the fan in DCS A-10 has way too little inertia, and it is what provides most of the thrust. So the issue is rather that the A-10 engines are way too quick to respond to throttle changes,

Nope. A-10 is fine. Why should such a small fan like on the TF-34 have a high inertia?

AFAIR after flying more than 5000hrs on airplanes equipped with A-10 engines, I'd say that throttle response at high RPM is as expected.

Spool up is too slow currently in the DCS hornet, and pitch stability in the landing config is a mess. There is a weird deadband in pitch axis as you decel to on speed as flaps actuate, but once trimmed, it holds AOA fairly well, but the deadband is still present to some degree. The flap transition moments are probably contributing here, and seem excessive. I have linear curves set.

The rpm may be spooling quickly, but the thrust output is very, very slow to respond. Aircraft feels underpowered in the approach config, period. Feels like flying a high bypass fanjet on an airliner.

It will get better, just don't get too frustrated at the moment with landing. If the Hornet flew this bad in real life, guys would eject over the ship and let the helo pick them up rather than attempt landing. ;)

The only way to fix this "deadband" is to go to Throttle Axis tune and set SATURATION Y to 83% for both Throttles. It works for Warthog and other Throttles as well.

Spool up is too slow currently in the DCS hornet, and pitch stability in the landing config is a mess.

It will get better, just don't get too frustrated at the moment with landing. If the Hornet flew this bad in real life, guys would eject over the ship and let the helo pick them up rather than attempt landing. ;)

Not frustrated at all. Presently it's challenging to wrestle the Hornet down ;) Even in its present state I'm enjoying the Hornet very much.

I'm just trying to point out areas which I think might be overlooked or which might need to be be re-checked.

Saw a Spanish Hornet a few weeks ago at the CIAV 2018 and it was the most impressive display I've ever seen!

When I first started flying the Hornet, I thought there was something wrong as well, I was often chasing the speed in the aircraft, and end up high over the deck or runway or rear-ending the carrier or short of the runway. But as I got some practice in, and learned how it responded, I found it quite responsive and very smooth.

 

Before you try and do the most advanced things with the Hornet, get used to it doing the most basic things. This is a simulation, it will take you time to master.

Just because you get used to it doesn't mean it's correct.

I don't care much if the slam acceleration from idle to mil is off by a second. I'm just pointing out that a jet engine generally reacts faster in the high RPM range. The acceleration from 80-88 is as wrong as it is from 88-96 IMO.

 

It doesn't make any sense why the engine needs to accelerate from 88-96% in the same timespan as from idle to mil.

If you advance the throttle the thrust/RPM increase is almost immediate and there's usually not a 3sec delay to achieve the desired thrust.

 

Here are a few examples where you can see/hear how fast the engines are spooling up and down. (the Pegasus engine isn't exactly known for it's fast acceleration)

https://youtu.be/aUifhhPLxpU?t=218

 

Presently you can't really use a quick throttle burst to make small corrections like in the above videos, because instead of a short, less than a second throttle burst, the engines require too much time to spool up and down again be able to use this correction method.

 

Another strange behavior is that the acceleration starts to slow down a few % before reaching the desired setting.

 

Nevertheless, if it's drag, pitch stability, spool rate, that are WIP, it's in its present state already a truly magnificent add on that's incredible fun to fly :) :thumbup:

Like I said in my post. The problem is gear drag. If profile drag is modelled incorrectly then it will feel as though thrust is the problem especially if drag increases as thrust increases to the point that the acceleration is very small.

Tell me, does the thrust response feel off when clean? Close formation is a good indicator of thrust response.

Have you downloaded the Natops or -404 engine manuals and checked rpm and engine thrust response times (acceleration over time etc)? I don't think tuning a DCS aircraft by listening to YouTube videos is going to produce accurate results

As an example, my testers build only requires 83% right now when on the glidepath in PAM. The engine modelling has not changed. Thrust response 'feels' far better with smaller throttle movements required to maintain correct flightpath.

P.s A 3 second delay to achieve the correct thrust is realistic but depends on your start rpm and desired rpm. Low bypass engines accelerate faster then high bypass engines. Smaller engines generally accelerate faster than larger engines. None of them have instantaneous thrust over a wide range, that would be rocket motors.

Spoke to a retired Hornet pilot today about this, he said it's WIP, he can't say much about the engine response, he needs more time in the sim. But one thing he pointed out is the fuel flow, he said it doesn't work right, if you set a specific FF for a known approx AS, you don't get it consistently.

A 3 second delay to achieve the correct thrust is realistic but depends on your start rpm and desired rpm. Low bypass engines accelerate faster then high bypass engines. Smaller engines generally accelerate faster than larger engines. None of them have instantaneous thrust over a wide range, that would be rocket motors.

Again, I'm talking about the upper RPM range. Engine acceleration 'over a wide range' means exactly nothing, because basically every jet engine accelerates slower at its lower range.

That's also the reason why many jet engines have an approach/flight idle and ground idle setting.

Don't know why you don't think (and don't believe your ears and disregard the RPM readout) that most jet engines accelerate rapidly in the high RPM range. I'm strictly talking about decades of RL experience.

Btw, Victory205 wrote that Spool up is too slow currently in the DCS hornet and isn't he Hornet pilot?

Spool up is too slow currently in the DCS hornet, and pitch stability in the landing config is a mess. There is a weird deadband in pitch axis as you decel to on speed as flaps actuate, but once trimmed, it holds AOA fairly well, but the deadband is still present to some degree. The flap transition moments are probably contributing here, and seem excessive. I have linear curves set.

 

The rpm may be spooling quickly, but the thrust output is very, very slow to respond. Aircraft feels underpowered in the approach config, period. Feels like flying a high bypass fanjet on an airliner.

 

It will get better, just don't get too frustrated at the moment with landing. If the Hornet flew this bad in real life, guys would eject over the ship and let the helo pick them up rather than attempt landing. ;)

Yeah, not that i know much but that transition to onspeed is very weird. I have to delay my break for a long time because i need time for the wrestling match to get to stable trimmed onspeed before the 180. I have to pull the stick into my lap an then it is like waiting for a rubber band to finally snap back before i can do small trim adjustments. And it snaps back hard. And then, finally it gets into a little groove and hangs there nice. That wrestling match seems not right.

Also, if i have a slightly low ball in close it seems pointless to try to correct that because I have to wait a long time to get enough trust to move it and waiting throws off my ability to judge the counter corrections with the trombone movements. I add the power and get nothing and hold it and then blast through the glideslope and bolter. It makes you just skip it and grab the one or two wire. And, that would certainly be incorrect compared to real life ball flying. In real life you would have enough response to move the ball back up smartly, and would of course do so.

I do feel that I need to be at 95%-mil to even keep the thing in the air when dirty, which may or may not be accurate, better minds than I can check that, but what weirds me out is this:

you fight to keep decent rate from going crazy alllll the way down, and if you let up on even 10% throttle you drop like a stone, but if you bolter, all of a sudden with mil power you're climbing at 15 degrees up and have to fight to keep the VV close to the horizon to not encroach past 500 AGL? Is this due to trim settings shifting on WOW?