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Autopilot could some fine tuning


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Autopilot response is pretty slow and it often over corrects, particularly in the vertical axis and Speed mode. 

 

An example: On takeoff, you rotate and pitch up to the command bars, and at positive rate, gear comes up and speed mode selected Then at 400ft, heading mode  selected, and than at 600ft, autopilot selected On. 

 

Aircraft is now climbing with the auto pilot on at the speed that was bugged when you hit speed mode. (say about 160kts as an example). 

 

At some point, usually around 1000 feet agl, you'll eventually want to speed up and clean up the aircraft. So you you dial in 250kts on the speed. Once you do that, the aircraft should smoothly pitch over, and adjust to just about level flight, in order to reach the new bugged 250kt speed. And once it does, it then smoothly pitchs back up and resumes the climb at that 250kts speed. 

 

When you do this in the aerosoft CRJ, it reacts to slowly, and never really pitches close to level flight. It will slowly try to get to the new bugged speed of 250, but it is still climbing at 3000fpm while it does! That is pretty unrealistic, and again, it should pitch over, fly just about level, until it reaches the new Speed you have set, and not still climb at 3000fpm while it's slowy trying to get there. 

 

Other times, it climbs below the speed that was selected. 

 

Just something that I've noticed. It just needs some fine tuning as it seems a little just a bit off. 

 

 

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The pilots on the test team were happy with it. The speed hold was called pretty much spot on and I was even asked to reduce the maximum bank angle at higher altitudes because it was banking too hard.

I flew in a real CRJ as a passenger not too long ago and none of the speed change phases after takeoff was even noticable. There certainly are no hard corrections. It's all very smooth.

 

Sorry, but I don't plan to change anything here.

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Thanks Hans for the guck reply. Right, it's pretty much there, just seems to me like some small adjustments could help. No hard corrections, it'll all happen smoothly in my example above as well. At any rate, it's just my take on it. And I also do know that it could have a lot to do frame rates and how the sim is performing, but I've tested it many times in many different scenarios, and that's what I've seen.  I'd be interested to hear what some other current real world CRJ pilots say, but anyway thanks for the reply and info on not planning to change anything on this. 

 

Jeff

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I fly the CRJ 200, 700, and 900 in the real world. All variants of the plane, when accelerating in SPEED mode, do exactly as @Jm8592 describes. It will pitch over to nearly level, only getting about a 100-200 fpm climb, accelerate to the selected speed, and then pitch up to hold that speed. If the Aerosoft CRJ is still getting 3000fpm during the acceleration process, that's extremely unrealistic, and not at all like the behavior of the real world airplane.

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I have just checked this with an acceleration from 250 to 300 kts passing FL100 and the behavior is correct. Nose went down to the minimum climb rate of 100 rpm and went up approaching 300 kts. 

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Well try it from the initial acceleration from take off to 250kts as I discribed above. 

On line up, sink your heading to runway heading, press toga on the power levers, set take off power, at Vr, rotate up to the command bars. At positive rate, gear up and press speed mode. Then at 400ft, press heading mode, and then at 600ft, turn on the autopilot. Let it climb there for a few while you wait to get to 1000ft agl, and then twist in the speed to 250kts, and watch.. What does it do for you? 

Does it decrease pitch to about level, 100-200fpm, while accelerating to reach the new bugged speed then of 250 then? 

 

If it is functioning correctly, at no point between the two speeds, should it be climbing at 3000fpm.

 

I'd like to find out if it is just me seeing this. If some other current real wold CRJ pilots would try it. I know there are a few on these boards. Just try and fly your real world take off profile, and see what it does. I only flew the 200 back in the day, but really, no aircraft will do that. 

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well, for my previous flights, apparently depending some parameters, the rate was always between 100-1000fpm while the speed increased. The behaviour seems to be pretty perfect.

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On 8/4/2017 at 11:44 AM, Jm8592 said:

 

 

An example: On takeoff, you rotate and pitch up to the command bars, and at positive rate, gear comes up and speed mode selected Then at 400ft, heading mode  selected, and than at 600ft, autopilot selected On. 

 

 

 

 

When I've flown the Aerosoft CRJ, when I rotate and pitch up, the command bars/FD doesn't give me a positive pitch, it usually just stays level. Is there something that I need to to on t/o to make sure it gives me the right pitch for climbout? I usually just have ALT and HDG mode set. 

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4 hours ago, Jm8592 said:

Well try it from the initial acceleration from take off to 250kts as I discribed above. 

On line up, sink your heading to runway heading, press toga on the power levers, set take off power, at Vr, rotate up to the command bars. At positive rate, gear up and press speed mode. Then at 400ft, press heading mode, and then at 600ft, turn on the autopilot. Let it climb there for a few while you wait to get to 1000ft agl, and then twist in the speed to 250kts, and watch.. What does it do for you? 

Does it decrease pitch to about level, 100-200fpm, while accelerating to reach the new bugged speed then of 250 then? 

 

If it is functioning correctly, at no point between the two speeds, should it be climbing at 3000fpm.

 

I'd like to find out if it is just me seeing this. If some other current real wold CRJ pilots would try it. I know there are a few on these boards. Just try and fly your real world take off profile, and see what it does. I only flew the 200 back in the day, but really, no aircraft will do that. 

My feeling is that you expect too much. As typically there are significant configuration changes until you are above 210 plus that in the lower airspace you have changing ATC requirements, I have never seen a IAS CLB hold in the early flight phase. What I have seen is stabilizing at 250 kts maybe at 5000 ft to engage IAS CLB hold for a straight SID segment to follow and then switch over to 280 at FL100.

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hum the default TOGA command must work (probably). Just assign a key to this command in your fsx/p3d in order to engage the t/o mode.

If you are using fsuipc you can also use the lvar ASCRJ_TQ_TOGA_1

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15 minutes ago, blahhh said:

hum the default TOGA command must work (probably). Just assign a key to this command in your fsx/p3d in order to engage the t/o mode.

If you are using fsuipc you can also use the lvar ASCRJ_TQ_TOGA_1

Okay so you need to use the TOGA command? Advancing the throttles to the TOGA detent doesn't activate it? 

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32 minutes ago, XFalcon750 said:

Okay so you need to use the TOGA command? Advancing the throttles to the TOGA detent doesn't activate it? 

No, this is not an airbus :) Throttle </\> AP :P

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22 hours ago, XFalcon750 said:

Okay so you need to use the TOGA command? Advancing the throttles to the TOGA detent doesn't activate it? 

Yes, that only sets, the engine power to toga mode through the fadec. If you want the flight director to go to toga mode, you push the black button on the side of the power levers. 

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22 hours ago, Propane said:

 

We use CLB from gear retraction up to cruise 99% of the time on the 700/900 IRL. Some pilots prefer V/S sometimes but mostly CLB. May differ per company but it should practically never maintain 3000ft while accelerating to a new speed in CLB mode.

 

TO/TO -> Positive Climb -> Gear Up, Speed mode, Nav mode. 

Exactly. This is what I've been trying to explain. Using the real wold take profile, for me, it hasn't been performing correctly. Has anyone else tried this profile? I'm still consistently getting 3000fpm+ climb while the auto pilot is trying to accelerate from V2+12 to 250kts.

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13 hours ago, Jm8592 said:

Exactly. This is what I've been trying to explain. Using the real wold take profile, for me, it hasn't been performing correctly. Has anyone else tried this profile? I'm still consistently getting 3000fpm+ climb while the auto pilot is trying to accelerate from V2+12 to 250kts.

Ditto here. 

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Hey Hans, sure, the example that I gave in the first thread is the real life take off profile, and again explained also in post 8.  Also described by another in the real world tips and techniques thread. See Propane's post. 

 

But no prob, I'll explain it again: 

This is a somewhat simplified version, because in real life, both the non flying pilot, and the flying pilot have duties, and in the sim obviously, your doing it all yourself, but the actions are the same.

 

To clarify, nothing is preselected on the FCP, and only the altitude level is set. Alt is not preselected, nothing is preselected. Just set the the first altitude that you are cleared to, or that's on the SID. Say 6000ft. as an example. 

 

On line up, sync heading to runway heading. Press toga on power levers. 

Advance power to about halfway, around 70% N1 to make sure engines are stable and together. Then set thrust to takeoff power. 

At V1, obviously you are committed, hand off the power levers and both on yoke. At Vr, smoothly rotate up to the command bars. At positive rate, gear comes up and press SPEED Mode. Then at 400ft agl, press heading Mode. Or it can be NAV, just select a lateral mode. Then at 600 ft. agl, select autopilot on. 

Now the autopilot is flying the plane, and climbing out at the speed that was selected when you pushed Speed mode at gear up, which will be around V2+12. Let it fly there, until you reach 1000ft. agl acceleration altitude. Now at 1000ft. agl and clear of obstacles, you'll want to accelerate and clean up the aircraft, bringing up the flaps, so twist in 250kts, on the speed. The aircraft will then smoothly pitch over to nearly level flight, 100-200 fpm, as it speeds up to reach the new bugged speed of 250kts. As it speeds up past 200kts. start retracting the flaps. And then once 250kts is reached, the aircraft will smoothly pitch back up and resume climbing at 250kts up to the 6000 ft you set. You can set climb power now. 

Basically: 

Positive rate--> Gear up, Speed Mode--> 400ft heading mode--> 600ft autopilot On. --> 1000ft accelerate to 250kts and retract flaps. 

 

Now, like I've mentioned in other posts on this thread, the issue is the Aerosoft CRJ won't smoothly pitch over to almost level in order to reach the new bugged speed of 250kts. It actually never gets there. It slowly tries, but ends up somewhere in between the the two speeds still climbing at 3000fpm+. And once it finally does get to around to 200-210kts and you retract the flaps, I've noticed it gets even worse, pitching even higher to 4000fpm+. Again, the real aircraft does not do this of course. 

 

But, I guess you've basically summed it up, with the fact that this just for entertainment proposes.  This is my first aircraft from aerosoft, so I may a have had a little too high expectations. I don't know?? And honestly, I'm not try to be the negative nancy, complaining and pointing out problems.  I just got back into flightsims this past spring, and saw this aircraft was being developed, and I was looking forward to it just like everyone.  I'm just pointing out what I've found in hopes that it may lead to a fix in order to make it a little better. 

 

I remember when the original FeelThere Regional jet Experience-CRJ came out 14+ years ago for fs9, and it was actually pretty accurate, especially the flight model and flight characteristics. Perhaps I was just expecting this to be similar. 

 

Anyway, you've done a great job with modeling the systems, and to get this accurate, along with some of the other bugs you are currently addressing, would make this a great aircraft! 

 

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It doesn't seem to matter, try it near max gross, or try it lighter, it has been doing this at all weights for me. If you follow the profile, once your at 1000ft alg, and on the autopilot, and climbing at the speed you set when you pushed Speed Mode after gear up, (should be around V2+12), then twist in 250kts and see what it does. 

Again, if you do this, the aircraft should pitch over to nearly level, and start accelerating until it captures new bugged speed of 250 that you set and then resume the climb at 250. You can set anything really, you can set 230kts, or 290 or 310. In the real aircraft, the result is the same. Smoothly pitching over to almost level flight, about 100-200fpm until it reaches whatever speed you set. Not still climb at 3000fpm, while getting there. The only way it should climb like this is if you selected a speed lower than the first speed, not higher.

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Usually I don't engage the AP before FL100 (this plane is awesome to fly by hand), I'll try next flight :)

Anyway @FL100, to increase the speed from 250 to 290kts in speed (climb) mode, the vertical speed is 100-1000 feets, depending the gw probably (it works 100% on 20 flights).

I'm not a pilot but a developper, if I need to build this algorhthm : more the delta between the current speed and the target speed is small less the vertical speed will change.

eg. I'm climbing @2000fpm and I need to increase the speed from 250kts to 290 kts I will not change the vertical speed from 2000fpm to 100 for 15 seconds then 100 to 2000...

I'm a cleavy boy and I'll calculate the best option, maybe 2000fpm to 1000fpm for 25 seconds then go back to 2000fpm.

(and if I've enought power - eg light gw - I'll not intervene at all on the vertical speed)

 

ps sorry for my poor english

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