Cruise Speed - throttle detents

[timmie k]

Just reporting, I am also having the majority of all the reported problems but there is one more thing I havent seen written on here (yet)...

 

After climbing to whatever alt, say FL330 the throttle will not hold the speed, as in, If left in climb detent - the AC will start slowing down usually slowly but it still slows down. If  using TOGA detent the AC will speed up considerably fast. If using FULL SPEED detent, the AC will quickly go past OVERSPEED. If dropping the throttles down to MAN the AC slows down rapidly. In the manual it says to move the throttles into the CRUISE position after reaching TOC, but Im not seeing a cruise position.

 

"quote the manuals...."During climb we already switched from Speed mode to Mach hold and were climbing with Mach 0.74 so there is no need to speed up after level-off. As soon as the cruising altitude is captured, reduce thrust to cruise setting."

 

Can you possible tell how to keep the AC flying at a chosen speed? (and I know there is no auto-throttle, thats not what im asking here, Ive ridden in front in the real RJ's a few times at my old job and I know when you set the throttles to give off a certain thrust, the throttles stay put and DO NOT require constantly shifting from different detents, also they DO NOT automatically click into "one detent or the other")

 

Thanks for a nice looking RJ anyways. Im sure these issues will get resolved sooner or later.

[nealmac]

1 hour ago, timmie k said:

If left in climb detent - the AC will start slowing down usually slowly but it still slows down.

Have you remembered to dial the speed bug up to 250kts (below 10000 feet) and then up to 290kts? It's actually quite easy to forget to do this if you're used to an aircraft with an auto-throttle.

[Cheyenne Chief Pilot]

AFAIK there is no cruise detent. The CRJ should maintain its speed in level flight with the throttles somewhere in the 'manual' range.

 

Deceleration in 'climb' detent makes me wonder whether you're too heavy for the altitude and/or too high for the aircraft weight?

[kenthom]

I can report the same problem.  Trying to maintain a steady speed is nearly impossible.  I monitor the winds and adjust for them but even with little head or tail wind it is difficult to maintain a steady speed.  The "up/down" indicator on the speed tape is constantly jumping up and down.  Throttle is extremely sensitive.  If I try to put in more null and turn down sensitivity I run into other problems with the throttle.  

[nealmac]

13 minutes ago, kenthom said:

I can report the same problem.  Trying to maintain a steady speed is nearly impossible.  I monitor the winds and adjust for them but even with little head or tail wind it is difficult to maintain a steady speed.  The "up/down" indicator on the speed tape is constantly jumping up and down.  Throttle is extremely sensitive.  If I try to put in more null and turn down sensitivity I run into other problems with the throttle.  

Have you retracted your flaps? Also have you advanced the speed dial to 250kts?

[kenthom]

I can report the same problem.  Trying to maintain a steady speed is nearly impossible.  I monitor the winds and adjust for them but even with little head or tail wind it is difficult to maintain a steady speed.  The "up/down" indicator on the speed tape is constantly jumping up and down.  Throttle is extremely sensitive.  If I try to put in more null and turn down sensitivity I run into other problems with the throttle.  

 

Yes and yes.   

[timmie k]

Hi,

6 hours ago, nealmac said:

Have you retracted your flaps? Also have you advanced the speed dial to 250kts?

 

 I always start out the climb at 190 or so, always climb with speed button on and set. Flaps are up around 1000-1200ft and speed goes up to 230, and stays there until 10000ft or so, then speed gets dialed up to 270-290 for the climb to altitude. Once cruise is reached "usually" you will have to bring the throttle back some to slow down to a steady speed. But there is no steady speed, only too slow or too fast!

 

Im still not hearing any answer regarding the manual saying reduce speed to Cruise. What is cruise? if its not somewhere in the manual range, and its not climb, and its not TOGA or MAX??

 

[timmie k]

9 hours ago, Enter display name here said:

AFAIK there is no cruise detent. The CRJ should maintain its speed in level flight with the throttles somewhere in the 'manual' range.

 

Deceleration in 'climb' detent makes me wonder whether you're too heavy for the altitude and/or too high for the aircraft weight?

Thanks also, but I have no deceleration during climb, only after I get to cruise alt. And I am quite sure that I have the AC configured correctly for my flights.

[JRBarrett]

5 hours ago, timmie k said:

Hi,

 

 I always start out the climb at 190 or so, always climb with speed button on and set. Flaps are up around 1000-1200ft and speed goes up to 230, and stays there until 10000ft or so, then speed gets dialed up to 270-290 for the climb to altitude. Once cruise is reached "usually" you will have to bring the throttle back some to slow down to a steady speed. But there is no steady speed, only too slow or too fast!

 

Im still not hearing any answer regarding the manual saying reduce speed to Cruise. What is cruise? if its not somewhere in the manual range, and its not climb, and its not TOGA or MAX??

 

 

Cruise setting" is whatever power setting you need on a given day, at a given altitude, and given outside air temperature to maintain your desired IAS or Mach. There is no "detent" for cruise - it will be in the somewhere in the upper part of the manual range below the climb detent.

 

In both the 900 and 700, I typically fly flights of about 1.5 hours duration with full passenger load and about 11,000 pounds of fuel at departure. Usually, at FL300-330 I find my cruise power setting "sweet spot" will be somewhere between 80 and 81.5 percent N1 for a Mach .76 cruise speed.

 

I don't see much if any "jumping" of the airspeed trend vector, even when using Active Sky weather injection, but I do have the AS turbulence settings turned down below 25 percent.

 

Jim Barrett

[Cheyenne Chief Pilot]

I'd also suspect a weather issue more than a CRJ issue. If your hardware throttles have enough lever angle and lever length, a cruise thrust setting shouldn't be too difficult - unless wx issues come into play.

 

BTW, the RW CRJ docs call it the "cruise range" (no cruise detent) - looks like Hans translated that into 'manual' (range) for the FMA indication cheat.

[metzgergva]

If your aircraft is in clean mode (flaps up, gear up spoilers down) and not overloaded, the required cruise power setting is slightly below the CLB dent.

Make sure Anti-Ice is off too!

If you see airspeed jumping, it may come as already stated from the turbulence settings in Aktive Sky which are much too strong by default: 25% is a reasonable value. Same for induced climb/descent: 300 fpm is much more realistic unless you have heavy wind shear.

 

[Hans Hartmann [OLD]]

2 hours ago, Enter display name here said:

BTW, the RW CRJ docs call it the "cruise range" (no cruise detent) - looks like Hans translated that into 'manual' (range) for the FMA indication cheat.

Yes, I did that to make sure that people understand that it's the range used for manual speed control. And it's not just used for cruise flight but for example for taxiing and descent as well. So, I daresay the RW CRJ manuals are wrong here

[richcam427]

There's a bug with the throttle scaling that I've notified Hans about where the initial position of the CRZ range is lower than the max, meaning that if you use a yoke (as I and many others do) it's impossible to achieve max CRZ thrust unless you use F3 on the keyboard.

 

Moving the throttles from CLB to the max CRZ range should not make the N1 value drop a few percent like it does. That makes it hard to hold speed, particularly if there's a strong-ish headwind, because about the top 2% of the CRZ range is unusable.

[metzgergva]

Not sure I understand:

MAX is not maximum cruise it is Maximum continuous power. So moving throttles forward you should see:

CRZ - CLB - TOGA - MAX

With no or very little change on N1 when moving from the upper end of the (manual) CRZ range to the CLB dent.

[PCEM]

I`m having the same problem with speed adjustment at cruise levels. Let me try to explain what I noted after several flights (not a lot but enough) and what I believe is the problem (maybe my statement of what I believe is causing the problem is wrong, please correct me)

 

In cruise level (doesn’t mater if it is FL300 or FL3600 or even FL250 for a short flight) to find the correct throttle input to keep the desired cruise sped is possible, but very difficult. The throttle adjustment offered by the CRJ, at least with my throttles rig, is very good. But it takes a long time to find the correct throttle settings to keep a constant speed. As mentioned above, is normal that when the weather is updated you should readjust the throttle input. 

 

The point I would like to bring up is the following: lets say that you are a little over powered and you speed is increasing just a little, let’s say 1 knots each 5 seconds.  At least what I remember from my old pilot and engineering days, your speed will go up due to your over power until the thrust/drag  ratio becomes equal, i.e. with more speed you will have more drag  and your over powered will be compensated and speed will become steady at some point above the speed for which you were overpowered. The same thing happens the other way when you are under powered (less speed=less drag)

 

What I noticed in the CRJ  is that the drag, at cruise level, doesn't seems to influence the speed as it should (I'm not a CRJ pilot so this is only my feeling). Let’s say that your speed is constant at Mach .74 with N1= 80.1%. If you increase, lets say, the power to 81% your speed will increase forever and you will go beyond the VNE. My personal opinion is that, with such a small variation in N1 the speed should not increase all the way to VNE, but just a little (maybe from Mach .74 to Mach .75 or .76, whatever) because the drag will also increase and will hold the speed a little bit over Mach .74. The same happens the other way, reducing power=reduces speed, less speed= less drag and the speed should be kept a little bit under the previous speed.

 

To summarize, it looks like the flight model is not considering the drag at cruise speed as it should, or at least, as I believe it should (which maybe I'm wrong)

 

By the way the aircraft is amazing and was the reason why I'm back to the FSX/Prepar v4 platform. I went to X-Plane 11 in the beginning of 2017 (OOM were driving me crazy). After the CRJ/Prepar v4, I came back and I’m really enjoying it again. However X-plane is also amazing. If possible...fly both!!

 

Cheers from the sunny Rio de janeiro!!

[DaveCT2003]

4 hours ago, PCEM said:

 believ

I`m having the same problem with speed adjustment at cruise levels. Let me try to explain what I noted after several flights (not a lot but enough) and what I believe is the problem (maybe my statement of what I believe is causing the problem is wrong, please correct me)

 

In cruise level (doesn’t mater if it is FL300 or FL3600 or even FL250 for a short flight) to find the correct throttle input to keep the desired cruise sped is possible, but very difficult. The throttle adjustment offered by the CRJ, at least with my throttles rig, is very good. But it takes a long time to find the correct throttle settings to keep a constant speed. As mentioned above, is normal that when the weather is updated you should readjust the throttle input. 

 

The point I would like to bring up is the following: lets say that you are a little over powered and you speed is increasing just a little, let’s say 1 knots each 5 seconds.  At least what I remember from my old pilot and engineering days, your speed will go up due to your over power until the thrust/drag  ratio becomes equal, i.e. with more speed you will have more drag  and your over powered will be compensated and speed will become steady at some point above the speed for which you were overpowered. The same thing happens the other way when you are under powered (less speed=less drag)

 

What I noticed in the CRJ  is that the drag, at cruise level, doesn't seems to influence the speed as it should (I'm not a CRJ pilot so this is only my feeling). Let’s say that your speed is constant at Mach .74 with N1= 80.1%. If you increase, lets say, the power to 81% your speed will increase forever and you will go beyond the VNE. My personal opinion is that, with such a small variation in N1 the speed should not increase all the way to VNE, but just a little (maybe from Mach .74 to Mach .75 or .76, whatever) because the drag will also increase and will hold the speed a little bit over Mach .74. The same happens the other way, reducing power=reduces speed, less speed= less drag and the speed should be kept a little bit under the previous speed.

 

To summarize, it looks like the flight model is not considering the drag at cruise speed as it should, or at least, as I believe it should (which maybe I'm wrong)

 

By the way the aircraft is amazing and was the reason why I'm back to the FSX/Prepar v4 platform. I went to X-Plane 11 in the beginning of 2017 (OOM were driving me crazy). After the CRJ/Prepar v4, I came back and I’m really enjoying it again. However X-plane is also amazing. If possible...fly both!!

 

Cheers from the sunny Rio de janeiro!!

 

rret

 

 

 

 

I believe you are correct on all points, and I concur. 

 

I used to have softwareI uised for testimg that would monitor and graph much of this in the sim, though it was for FSX.  I will try to find it, and see if I can get it workinng.

 

Best wishes.

[PCEM]

Thank you Dave!!

 

cheers!!, Plinio

[metzgergva]

I have just done a short test at FL250. I have added 0.5% N1 which is about 5% more power. The result is a speed increase of 10 kts indicated after 8 min and reducing aircraft weight by 185 kg fuel burned. As parasite drag increases form speed, the induced drag is decreasing at the same time from less pitch due to decrease of weight and that why these small power changes have this speed effect. Nothing wrong with it. As we have no autothrottle, no CRJ pilot is chasing his speed target on the knot. Just let it fly!

[PCEM]

Hi, Alexander,

 

Thank you for your above explanations.

 

I did a similar experience yesterday, but at FL360 (sure less drag than FL250), and the results were bit different than yours at FL250. Here are the results:

I arrived at TOC at FL 360 at Mach 0.74 and adjusted the throttles to 80.2% N1. The speed was decreasing slowly and after some minutes It was at aprox. Mach 0.72. I decided to increase the power to 80,6% N1 and the speed started to increase, after some minutes I was over-speeding at aprox. Mach .80.

 

I’m not a CRJ pilot but, it doesn’t seem reasonable that with such a small increase of N1, and actually with my throttles I was not able to set 80.4% of N1 ( or something in between 80.2% and 80.6% of N1), the speed increased all the way from Mach .72 to Mach .80 in some minutes. I would like to mention that I do not have the experience that you have and maybe this is perfectly normal in the real aircraft.

 

My only question is: why when you are a bit under power, following what you stated, the speed does not stabilize at lower value (or even starts to increase again). In my flights when you are slightly under power the speed keeps falling until the stall speed.

 

Actually I’m not aiming to nail a speed like in autothrotle aircraft, what I’ would only wish to have is that the speed stabilizes a bit over or a bit under the desired speed if I not able to nail the N1=Speed (consider that small adjust needs to be done after a while). The problem is that at least for me, the speed is never stable is always increasing or decreasing whatever N1 you have. I understand that if you set N1 after some time with less weight=less pitch=less drag you will have to reduce your power to keep that pre-desired/set speed, but I believe that the changes will not be so “fast” that will lead to an over-speed situation after some minutes.

 

Once again sorry if I’m not correct, I’m only curios about this situation which for me, being a virtual pilot, does not allow me to watch a movie while doing a medium-long flight….LOL.

 

Thank you and cheers!!

 

Plinio

[metzgergva]

Need to see if I can reproduce this at FL360. Your actual weight and fuel would help to set things up.

[PCEM]

Hi Alexander,

 

I'm not sure about the exact figures. but I would say that was Aprox. the following:

 

Date: saturday Sep/9 night time in Brazil (around 22:00) Using Active sky weather

Departure from:  YSSC

Destination: YMML

Passengers: Aprox. 60 souls

Cargo: aprox. 1500 pounds

Departure fuel: Aprox 6.000 pounds

CRJ 700 Qantas link livery

Windows 10

Prepar v4

I7 4790 K OC 4.8Ghz

GTX 1080 MSI

ORBX autralia /  Holgermesh autralia

YMML, YSCB Orbx

 

Thank you for your assistance on this.

 

Cheers!!

 

Plinio

 

 

[metzgergva]

Hi, did a test at FL360 and your weights.

You can see from screens that I had about the same engine data. Standard clear weather.

I started pretty stable with 81.5% N1, 1430 FF and M.742 - screen_01

I then increase the minimum my throttle levers can do which is 0.5% (which is a bit more than you can achieve with a single hit on F3).

Remark: Make sure you corrected assignments if you want to use keyboard inputs F2 and F3 to Throttle decrease/increase as by default the assignment are not the same magnitude.

With increased speed, the N1 and the FF climbs (increased turbine intake pressure) and by taking the throttle back a bit I stabilized at about the same 81.6% N1 but a 1490 FF a plus of 4.2% thrust. The speed stabilized at M.770 or +11 kts. - screen_02

Then reduced throttle to the same FF as started the exercise (1430) and the aircraft slowed down - screen_03

Arriving at M.074, I increased a bit again and stabilized at M.074 with a 1405 FF, a tad slower than started, a bit less 81.3 N1 and 1405 FF but burned 5445-4870=575 lb in these 10 minutes.

 

My conclusion is that I can control the speed at about +/- 5kts or 0.03 mach. The aircraft is reacting correctly, it is just the resolution of our input device that may result in a small difference of actual versus desired speed.

And a learning is that N1 is not the same thrust at different speeds as there is more airflow and a resulting higher FF when the speed increases. This also explains that at low speeds higher up it is difficult to accelerate.

[PCEM]

Good morning Alexander,

 

Thank you very much for your clear explanations… now it is clear that the difference in my flight was the weather injected by AS4 (sorry to not consider this factor in my other posts, my fault!!). As known and as already stated in this topic, when you start to inject different weather parameters, the aircraft starts to react in a different way, which is how it should be.

 

But fully agree with you that considering "clear sky", as per your above test flight, the CRJ is reacting correctly. Therefore for me, the problem is solved. 

 

I would like to take the opportunity to thank you for your quick and professional support.

 

Cheers from Rio,

 

Plinio

.

 

 

 

 

[metzgergva]

Glad I could help!

[Hans Hartmann]

Because we believe this topic has been answered we have closed it. If you have any more questions feel free to open a new topic.