what's going on with the pitch control?

[shagrat]

vor 1 Stunde schrieb River:

anymore aviation secrets to share ?

F-15E, Full Flaps, Take-Off trim set, max afterburner take-off. Standard day.

Rotate by pulling half aft stick for about a second, then neutral and hold 10-12° nose up (NOT flight path!):

Gross weight 40k lbs - Rotate at 110 kts

Add 5 kts (adjust for air density) for every 5k lbs over 40k gross weight...

Do not pull more, after rotation, let the aircraft gain speed and fly itself off the runway.

After lift-off raise gear and flaps and directly trim nose down 1-3 clicks to compensate for nose up T/O trim attitude. Climb at 300-350 kts to cruise attitude.

Edited July 19, 2023 by shagrat

[River]

47 minutes ago, shagrat said:

F-15E, Full Flaps, Take-Off trim set, max afterburner take-off. Standard day.

Rotate by pulling half aft stick for about a second, then neutral and hold 10-12° nose up (NOT flight path!):

Gross weight 40k lbs - Rotate at 110 kts

Add 5 kts (adjust for air density) for every 5k lbs over 40k gross weight...

Do not pull more, after rotation, let the aircraft gain speed and fly itself off the runway.

After lift-off raise gear and flaps and directly trim nose down 1-3 clicks to compensate for nose up T/O trim attitude. Climb at 300-350 kts to cruise attitude.

 

Mate I don't need takeoff tips.

It's about how it's programmed when you leave the runway with the tires. There are aircraft in DCS that have done it right, the majority in fact and others lack a proper modeling for a smooth takeoff roll.

You do you and be the best pilot on the planet if it helps but nobody can tell me the Mirage 2000, the F 15E, the Harrier and the Mig 21 did a good job modeling an aircraft leaving the runway surface.

F1 was bad too, didn't fly it the last month though. Can't give an opinion here.

I've watched videos of the above mentioned aircraft taking off, the DCS takeoff roll is a joke compared to RL. 

F 14, F 18, F 16, A 10, all the DCS trainer aircraft, F 86, Mig 15, F 5, pretty much any other module got this right. And they have all different airframe shapes, wings and engines. Thats a bad excuse.

I think the devs produced one of the best looking modules we have in DCS, Heatblur level I'd say. The programming of a sweet and well controlable takeoff is not a strength of them. Some aspects of the FM are always questionable too. See this thread for example.

Edited July 19, 2023 by River

[draconus]

3 minutes ago, River said:

DCS takeoff roll is a joke compared to RL

You mean your take off?

[River]

9 minutes ago, draconus said:

You mean your take off?

 I hope you find your freedom in life, it's defo not between keyboard and chair. 

[BIGNEWY]

Folks keep it civil please 

[Nealius]

2 hours ago, shagrat said:

Do not pull more, after rotation, let the aircraft gain speed and fly itself off the runway.

This is the part I can't replicate. Flying off the runway always occurs near simultaneously with rotation even when I use takeoff speeds for my GW from the -1. I got rid of PIO after takeoff, but when returning stick to neutral to hold pitch angle the nose bunts down. When I put in the ~3 clicks of ND trim my pitch attitude also drops instead of maintaining 10-12 NU. 

[shagrat]

vor 2 Stunden schrieb River:

Mate I don't need takeoff tips.

Well, that's what the manual says... If you think you have a better procedure, you want to train, go for it...

[shagrat]

vor 36 Minuten schrieb Nealius:

This is the part I can't replicate. Flying off the runway always occurs near simultaneously with rotation even when I use takeoff speeds for my GW from the -1. I got rid of PIO after takeoff, but when returning stick to neutral to hold pitch angle the nose bunts down. When I put in the ~3 clicks of ND trim my pitch attitude also drops instead of maintaining 10-12 NU. 

It's a bit tricky to keep the nose at 10° if your rotation speed is on the lower end. Need more practice. Problem is we have just HUD and numbers... But going by the number it's getting there.

First take off was violent, as I kept the stick aft underestimating the fuselage... Guess I scraped the runway with the nozzles. The half stick for a second, then keep 10° as per the manual, made it way more manageable...

[Holbeach]

45 minutes ago, shagrat said:

It's a bit tricky to keep the nose at 10° if your rotation speed is on the lower end. Need more practice. Problem is we have just HUD and numbers... But going by the number it's getting there.

First take off was violent, as I kept the stick aft underestimating the fuselage... Guess I scraped the runway with the nozzles. The half stick for a second, then keep 10° as per the manual, made it way more manageable...

Bare in mind. The speeds for a normal T/O are calculated at 10 deg. for a plane without conformal tanks.

With CFT it's 12 deg.

..

[WizzRD]

On 7/19/2023 at 3:33 PM, Nealius said:

When I put in the ~3 clicks of ND trim my pitch attitude also drops instead of maintaining 10-12 NU. 

Edit:

With DCS Open Beta 2.8.7.42583 RAZBAM did change the TO behavior, thus Method 1 (by the book) is now the preferred one.

The 12° is your optimal fly out attitude. You must not establish that right after TO. Clean up the plane, trim 1G and then establish a 12° attitude. Made a little Vid to demonstrate, 65k GW, light Wind/ Turbulence; first TO is by the book at  140, second at +10 where you basicly rotate and TO in a fluid motion.

 

Edited July 25, 2023 by WizzRD

[Nealius]

Finally cracked it! I had the incorrect assumption that rotation should happen while the stick was held aft for that one second. I found that holding the stick aft for one second, then easing off (not sure if I went all the way to neutral or not), the nose then rotated up after I had already eased off the stick, almost like magic.

[pii]

On 7/19/2023 at 12:16 PM, WizzRD said:

The 12° is your optimal fly out attitude. You must not establish that right after TO. Clean up the plane, trim 1G and then establish a 12° attitude. Made a little Vid to demonstrate, 65k GW, light Wind/ Turbulence; first TO is by the book at  140, second at +10 where you basicly rotate and TO in a fluid motion.

 

12 degrees? I like 80  up up and awaaaaaayyyyy!

[Ramstein]

On 7/19/2023 at 3:52 AM, shagrat said:

...so you may have general problems with following individual procedures for specific planes?

Comparing the weird take off of an AV-8B Harrier to the take off with an F-15E, or a delta wing, Mirage2000 and MiG-21 sounds definitely weird, as the flight characteristics of not one of these airplanes are really "a match".

 

^this

you are compAring AIRCRAFT this that don't cOMPARE. imho. btw, THE f-15e on takeoff is a rollercoaster.

On 7/23/2023 at 6:16 AM, Nealius said:

Finally cracked it! I had the incorrect assumption that rotation should happen while the stick was held aft for that one second. I found that holding the stick aft for one second, then easing off (not sure if I went all the way to neutral or not), the nose then rotated up after I had already eased off the stick, almost like magic.

let it lift, with a couple degrees at most of pitch... if you lift two much it bucks like a wild horse..

Edited July 26, 2023 by Ramstein

[shagrat]

vor 10 Stunden schrieb Ramstein:

you are compAring AIRCRAFT this that don't cOMPARE. imho. btw, THE f-15e on takeoff is a rollercoaster.

You may want to read the post, I commented. He(!) compared the F-15E to be similar in T/O behavior... I pointed out the flaw in the logic, as they are totally different.

As for the "Rollercoaster" just have a look at WizzRDs video what was possible, even before Monday's update, by simply following the manual.

 

[draconus]

14 hours ago, Ramstein said:

you are compAring AIRCRAFT this that don't cOMPARE. imho. btw, THE f-15e on takeoff is a rollercoaster.

let it lift, with a couple degrees at most of pitch... if you lift two much it bucks like a wild horse..

Very scientific take, I can't tell if it's a complain or praise.

[skywalker22]

If this is how F-15E it should suppose to fly?

If so, no thank you, I really don't like it. I am no expert what so ever, but this, this constant swinging up and down? LOL. Can't be made that way IRL, just can't.

[KlarSnow]

you are pulsing the stick and the aircraft is then entering into oscillations that are damped out by the CAS. What is incorrect about that? You are supposed to smoothly fly the aircraft where you want it, not snap the stick back or forwards and let it go. That would and should result in oscillations here.

Edited July 28, 2023 by KlarSnow

[av8orDave]

13 minutes ago, skywalker22 said:

If this is how F-15E it should suppose to fly?

If so, no thank you, I really don't like it. I am no expert what so ever, but this, this constant swinging up and down? LOL. Can't be made that way IRL, just can't.

What are you trying to show here? Looks like you're yanking the plane up and down. The stick inputs look really extreme and exaggerated. Are you referring to the plane's tendency to slightly return to it's prior pitch after the pull on the stick? I'm honestly not sure what I'm supposed to be seeing. Not being critical, just trying to understand. 

After the latest patch the pitch response seems pretty good to me, maybe even a bit too stable and lacking a need to trim. I'd actually be surprised if the real F-15E is this steady and "hands-off" on the pitch axis. It almost doesn't require any trimming in level flight.

[KlarSnow]

Its not supposed to require trimming in level flight. The flight control system should be trimming you to 1 G level flight (after you trim out the takeoff trim).

[av8orDave]

18 minutes ago, KlarSnow said:

Its not supposed to require trimming in level flight. The flight control system should be trimming you to 1 G level flight (after you trim out the takeoff trim).

Understood. I guess my question is whether the real aircraft feels like it is flying “on a rail.” It currently feels so stable in level flight that it almost doesn’t feel like flight.

[Rainmaker]

52 minutes ago, davidrbarnette said:

Understood. I guess my question is whether the real aircraft feels like it is flying “on a rail.” It currently feels so stable in level flight that it almost doesn’t feel like flight.

Its not a dynamically unstable airframe. This is why it will fly just fine with no CAS at all in most cases. Its built to be aerodynamically stable. 

[Raven (Elysian Angel)]

I don't know if something changed in the last 2 patches or if it's just me getting a bit more used to the airframe, but my take-offs are buttery smooth now and exactly how I'd expect them to be like, without using a curve for pitch
Rotation is very smooth and the watermark stays at 10-12 degrees without oscillating between 10 and 15 like it used to just after release 

[shagrat]

vor 11 Minuten schrieb Raven (Elysian Angel):

I don't know if something changed in the last 2 patches or if it's just me getting a bit more used to the airframe, but my take-offs are buttery smooth now and exactly how I'd expect them to be like, without using a curve for pitch
Rotation is very smooth and the watermark stays at 10-12 degrees without oscillating between 10 and 15 like it used to just after release 

They tweaked the flight model AND we get better at the inputs. Muscle memory clicks, it seems.

[Abahji]

4 hours ago, KlarSnow said:

you are pulsing the stick and the aircraft is then entering into oscillations that are damped out by the CAS. What is incorrect about that? You are supposed to smoothly fly the aircraft where you want it, not snap the stick back or forwards and let it go. That would and should result in oscillations here.

 

Seems pretty obvious he is demonstrating centering. He is simply releasing the longitudinal input. This is basically one of the flight tests conducted IRL to evaluate the longitudinal stability of any airframe.
The Strike Eagle module has what is called a “Positive Centering” characteristic in the longitudinal axis as it is currently programmed. Especially evident with full CFTs at high GW.
If the nose returned to the exact same pitch attitude when the control stick is released that would be called “absolute centering.” 
Centering makes the nose want to bounce or snap back to its previous trimmed state (position).

The positive centering effect of the nose bouncing back several degrees upon control release can also be dramatically affected by aircraft CG IRL.
It has been pointed out by some really smart dudes in previous posts, that the nose in the Strike Eagle became very heavy compared to the Chuck. This moves the CG forward and increases the positive centering characteristics and also positively affects longitudinal stability (read, not as nimble). 
Additionally, the Strike Eagle’s CG moves quite a bit during normal flight, the CFTs and external tanks gradually empty, etc. etc.. Which is wonderfully evident I might add.

Long winded and pedantic way of saying that the positive centering characteristic of the Strike Eagle at high GW might be exactly what Razbam is aiming to simulate?
And thinking about it, can we do accelerated stalls in the Strike Eagle, or DCS for that matter?  
I’m not sure, but I am really starting to fall in love with her, warts and all. Such a cool module!

Centering = The ability of the longitudinal cockpit control and the longitudinal control surface to return to and maintain the original trimmed position when released from any other position.

Control System Oscillations — oscillations in the longitudinal control system (elevator and cockpit control stick) resulting from external or internal disturbances.

 

[draconus]

4 hours ago, davidrbarnette said:

aircraft feels like it is flying “on a rail.”

I bet your mission has 0 turbulence which is rare case IRL.