Engine Response to throttle input?

On a Saitek X52 but I'll try it thanks

This is what the Navy Hornet pilot said about the DCS F/A-18 flt model in his vid.

"I gotta say it feels like there's a little bit of too much lag, or too much drag or something like that with the throttle response, because sometimes I find myself, I gotta go into burner with a relatively simple maneuver like a 30 degree angle of bank, it just seems like too much..."

So that's what a r/l Hornet guy says.

Any official comment Wags?

Cheers,

Idle RPM to 99% takes less than 5 seconds. That's not a slow response.

Excessive drag seems more likely, and would create the illusion of slow engine response (to throttle up).

Idle RPM to 99% takes less than 5 seconds. That's not a slow response.

 

Excessive drag seems more likely, and would create the illusion of slow engine response (to throttle up).

exactly what I thought, too

Any official comment Wags?

there have been many concerns already raised about it, ed is well aware, and if wags had to personally address the concerns of every individual i dont think he would even have time to sleep.

maybe you should show some consideration.

more qualified analyses have been made before in this thread:

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

Another video here, look at how much pilot #2 moves his throttles after the 90!

Super hornet I guess but all the same, makes my Warthog throttles look super responsive...

there have been many concerns already raised about it, ed is well aware, and if wags had to personally address the concerns of every individual i dont think he would even have time to sleep.

maybe you should show some consideration.

 

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

It was a simple question, not a demand. lol. :music_whistling:

I wouldn't worry about it lobo. probad doesn't seem to be a people person. :music_whistling:

I was about to post the same, throttle response seems a bit slow to me, and I find myself pushing the thottles to MIL a bit too much on downwind and especially during the base turn.

P.S. F-110 Ge100 (it's the F-16 engine) takes ~3 seconds from idle to full A/B, so 5 seconds is a long time, but I don't know if it's realistic for a GE404.

Just my 2 cents.

I was about to post the same, throttle response seems a bit slow to me, and I find myself pushing the thottles to MIL a bit too much on downwind and especially during the base turn.

 

 

P.S. F-110 Ge100 (it's the F-16 engine) takes ~3 seconds from idle to full A/B, so 5 seconds is a long time, but I don't know if it's realistic for a GE404.

 

Just my 2 cents.

Well FWIW wicki says this about the GE404:

"It also demonstrates high responsiveness to control inputs, spooling from idle to full afterburner in 4 seconds."

Article in FlightGlobal https://www.flightglobal.com/FlightPDFArchive/1981/1981%20-%203726.PDF says:

"The F404 is very responsive, typically accelerating from ground idle to military power in under 4 seconds."

In the sim I'm seeing (based on FF) idle to full AB in approx 7 seconds.

This is very alien to most sim pilots and IRL pilots because only the Navy fly this way when landing at the carrier or when always practicing at an airfield. The power feels off to most because your are flying the backside technique at the optimal wing coefficient and not a normal approach. Controlling speed with the stick and rate of descent with the throttle. Curly (Engineer) wrote and provided great links in this post here and more in this one.

 

 

Quote

"It was found in a lot of aircraft configurations that the lift to drag ratio decreases at high lift coefficients. Total drag increases with decreasing airspeed, this is as the region of reverse command or the backside of the drag curve."

 

He also has this thread going about some change he thinks are needed to the FCS.

 

I have a thread consolidating On speed AOA here.

 

 

Also, make sure you are under 33,000 pounds when landing or she becomes a real pig to fly on speed AOA.

Actually I’m well aware of controlling descent with throttle and stick for speed. It’s how you learn in a Cessna 152/172

My point was regarding the spool time of the engine compared to throttle input. Not the reaction of the aircraft itself to the throttle input in terms rate of descent etc. The lag is noticeable between input and engine spool time reaction.

This is very alien to most sim pilots and IRL pilots because only the Navy fly this way when landing at the carrier or when always practicing at an airfield. The power feels off to most because your are flying the backside technique at the optimal wing coefficient and not a normal approach. Controlling speed with the stick and rate of descent with the throttle. Curly (Engineer) wrote and provided great links in this post here and more in this one.

 

 

Quote

"It was found in a lot of aircraft configurations that the lift to drag ratio decreases at high lift coefficients. Total drag increases with decreasing airspeed, this is as the region of reverse command or the backside of the drag curve."

The flight test world also teaches a backside approach for flying precise air speeds and AOA's, since it works on both the front and back.

This is very alien to most sim pilots and IRL pilots because only the Navy fly this way when landing at the carrier or when always practicing at an airfield.

 

I'd like to know where you got this idea from... controlling AoA with the stick and descent rate with the throttle is exactly what they teach in any flight school and is the landing technique in just about every aircraft ;)

The spool time has nothing to do with this, but as others have said, it's simply how long it takes to go from X% rpm to Y% rpm. That's what seems off in the current implementation.

+1

I experienced several situations in which I wasn't or was barely able to recover from a low-speed, high-AoA situation due to an extreme slow aircraft response on full MIL or even MAX - it felt like there is no response at all and the aircraft just stays in a descent rate. Everything in such situation was just wrong: maintaining pitch or increasing pitch. There was just a total lag of the power I expected or an extreme amount of drag. Compared to the M2k one of them is wrong, since the thrust-weight-ratio of the Hornet is better. From my feeling I would say the Hornets engines do not deliver what the pilot would expect.

In my experience so far, the engines will respond about 2 seconds after tiny throttle movements when properly on-speed, but if you deviate from on-speed with a high neg VSI (say in a turn that one does not compensate for with power beforehand), notice your speed increase. That increase is what makes you *think* that the engines are not responding quickly enough because you have to add even more throttle to bring it out of the dive, sometimes at full MIL.

You can see the response easily by flying straight and level on-speed, move the throttle just a tiny bit and you will see it climb easily within 2 seconds.

I'd like to know where you got this idea from... controlling AoA with the stick and descent rate with the throttle is exactly what they teach in any flight school and is the landing technique in just about every aircraft ;)

You cut half the post off, I was spicifficly talking how the navy do it and not GA. An engineer here had a very hard time teaching a pilot with 30 years of experience how and why the navy do it this way. How many AOA indexers are on these GA aircraft when getting shown all these methods?

This video explains a little more just how much more on the backside the Navy fly compared to any GA. This is an addon for GA, not standard equipment. Flying Aspen's Angle of Attack System Video

The spool time has nothing to do with this, but as others have said, it's simply how long it takes to go from X% rpm to Y% rpm. That's what seems off in the current implementation.

I was thinking this could also have something to do with extra drag as well that's all, while fly the on speed AOA. So a little bit of both that needs tweaking perhaps.

I didn't test the numbers yet, but:

My biggest concern is, that the Hornet compared to the Mirage is first of all not able to gain any speed back. It feels like flying a 737 and not a fighter. And that with a SIGNIFICANT better trust/weight-ratio (0.96 loaded, 1.13 loaded with 50% fuel) than the Mirage (0.7 laoded weight) has.

Hornet

gross-weight: 36,970 lb dry thrust: 2x 11,000 lbf (49 kN)= 22,000 lbf (98 kN) -> thrust:weight-ratio: 0,595

with AB: 2x 17,750 lbf (79 kN)= 35.500 lbf (158 kN) -> thrust:weight-ratio: 0,960

Mirage 2000

gross-weight: 30,420 lb thrust dry: 14,500 lbf (64.3 kN) -> thrust:weight-ratio: 0,476

with AB: 21,400 lbf (95.1 kN) -> thrust:weight-ratio: 0,703

So in any situation the Hornet SHOULD feel MUCH more powerful, especially with AB it should feel like 1/3 more powerful than the Mirage. But the opposite is the case.

We could test that felt impression in a special setup. Like clean aircraft, 100% fuel:

1. climb to 10.000, accelerate from 150 kts to 450 kts and see what time they need.

2. start at 1000 ft. 300 kts., pull 90 degrees nose up and see in what time you are at 25.000 ft. and with what speed you hit that altitude.

3. 5000 ft. 120 kts. level flight, full AB accelerate level until 400 kts.

It kind of remembers me at a time in the past when the Mirage felt like a brick at low speeds before the flight-model changed. Nowadays the Mirage feels like a fighter actually, but that wasn't the case from the beginning. In the past you hadn't been able to recover from a very-low-speed-regime in the Mirage, but you fall out of the sky in full burner basically. Today that isn't the case anymore in the Mirage. But the Hornet feels a bit like that - not that bad as the Mirage was before, but close to it.

The comparison of thrust to weight ratios completely ignores drag.

I can't find any numbers, but the Mirage's delta wing suggests it's a much more slippery aircraft than the Hornet.

The comparison of thrust to weight ratios completely ignores drag.

 

I can't find any numbers, but the Mirage's delta wing suggests it's a much more slippery aircraft than the Hornet.

But frontal area is just one aspect of drag, and I'm not convinced the Mirage has significantly less than the Hornet, especially once you factor in thrust.

From NATOPS 7.3.2 Approach

Avoid overcontrolling the throttles as thrust response is immediate.

Nozzle scheduling might be something else to look at

I fly both the VRS FA18E (P3D) and DCS FA 18C. The VRS bird's FM has been verified by FA18E drivers and require ~~ 75-80% power on final (40,000#) and response is very quick. What I see in the DCS "C" is power on final (35000#) require 85-95% power with throttle response very slow, if sink rate is over 1000FPM (dirty), burner may not stop the altitude loss, on final at the boat that is BAD!!!

I fly both the VRS FA18E (P3D) and DCS FA 18C. The VRS bird's FM has been verified by FA18E drivers and require ~~ 75-80% power on final (40,000#) and response is very quick. What I see in the DCS "C" is power on final (35000#) require 85-95% power with throttle response very slow, if sink rate is over 1000FPM (dirty), burner may not stop the altitude loss, on final at the boat that is BAD!!!

I tend to agree, while you cannot compare a SuperHornet with a Hornet, the FM of the F18C is subject to be tuned and should be tuned.

I have watched various cockpits videos and one things is the fact that the pilot keeps pulling back and force very quickly the throttle on 3/4 mile. When I try the same in DCS, it is a fail.

https://www.youtube.com/watch?v=NmGDl5WS0yk&t=34s

I fly both the VRS FA18E (P3D) and DCS FA 18C. The VRS bird's FM has been verified by FA18E drivers and require ~~ 75-80% power on final (40,000#) and response is very quick. What I see in the DCS "C" is power on final (35000#) require 85-95% power with throttle response very slow, if sink rate is over 1000FPM (dirty), burner may not stop the altitude loss, on final at the boat that is BAD!!!

Hey Pop, I think we'll change our opinions about throttle response when the devs listen to this "Curly" guy in the Bugs forum. I had to read it 4 times to get it through my cranium but I think he really nailed it! In my amateurish opinion it's the FCS that mekes the throttle response look bad.

Hey Pop, I think we'll change our opinions about throttle response when the devs listen to this "Curly" guy in the Bugs forum. I had to read it 4 times to get it through my cranium but I think he really nailed it! In my amateurish opinion it's the FCS that mekes the throttle response look bad.

Link?