Idle thrust, throttle override and ZFW/GW

[Iain]

Hey Jan

I am starting to get some more time on the aircraft again, maybe I found some bugs, or maybe user error or settings not set correctly.

- If I add 12 tonnes payload, I get a ZFW of around 45.3, then I add 5.0 tonnes of fuel, and my GW should be 50.3.  However, by inputting 45.3 into the FMC, with 5 tonnes of fuel showing in the gauges straight after a refuel, the FMC is giving me around 47 GW?  The reason this caught my eye, was I took off from Stansted to Edinburgh, trim was correct at 4.2, pulled gently back at Vr, nothing..pulled harder, and maybe at 160kts she became airborne.   Strange...as never had that before.  So after a 2 hr turnaround, I setup the FMC for the return and checked the values carefully and saw this discrepancy in the FMC.  I can put the GW manually into the FMC, but then the ZFW is calculated and is wrong.  I'm at work now, but will do a flight tonight (East Midlands - Frankfurt (can you tell I would like the cargo version!)) and will check this again.  

 

- When trying to slow to flaps speed during decent, I feel that the speed isn't bleeding off like pre-patch.  1000fpm, idle thrust, speed brakes out, and speed is stable or even increasing slowly.  The ghost throttle picture shows the throttles are idle, but N1 is around 31.  If I move my own CH pro throttle back to idle, the N1 drops to 28, if I push my throttle forward slightly, N1 is 31, if I push it more forward, N1 stays at 31.  So it seems my throttle is overriding the AT of the aircraft, but only by a small percent, and I think only at idle, but I need to test this.  But this small amount of N1 makes a difference when trying to slow down.  Not sure if this is a bug or some setup problem I have.  I will test it more later.

 

- Weather radar seems to be giving constant yellow returns in clear skies, not matter what altitude and pitch angle.  Using SM pro (will switch to UWXP when it's stable).  Can't remember having this problem before, I'm not expert in WX vs Terrain radar, I tend to takeoff with terrain on, and at a few thousand feet, switch of terrain and put on Wx.  Bug, user error?

- If you leave Nav 1 on the ILS frequency, on takeoff, you usually get a glideslope warning.  Something I'm familiar with in this aircraft since the beginning.  Is this simulated correctly?  There are plenty SID that require turns at a certain height, or distance from the airport, with the distance being from the ILS, so the ILS must be tuned to follow the procedure.  Maybe I am missing a trick here?

 

- Lastly, the flight model, wow, I put on experimental flight mode.  Now she yaws and wallows through the air, you actually have to fly it, and put in the effort to hit the touchdown zone even in a calm breeze. like stirring spaghetti with a long spoon!  Reminds me of my glider days in Scotland, stick and rudder were never sitting still.  Absolutely love it!  This is non beta, so don't know if it's the patch, the flight model, ASXP or something else..., but it's great! 

Edited June 26, 2020 by Iain

[Litjan]

Hi Ian,

your first issue sounds very much like a pound/kgs conversion problem. Make sure you have set the preferences up correctly for your preferred units and enter those correctly, too. I haven´t observed any problems with the fuel  weight getting calculated correctly, but you never know...maybe you can snap a screenshot when it happens?

The speed not bleeding at 1000fpm is not what I observe - you need about 1200 for idle at 210kts (minimum drag) or about 1500 at 250kts. Make sure that you have no other plugins interfering. 31% N1 is normal for "flight idle", we overrule the hardware throttle position when at idle to at least have the engines maintain that (while in the air).

When using the weather radar with ANY third-party weather addon all bets are off. Nothing was changed with regard to its operation since 1.2.

I have observed the glideslope warning, too. I think in the real aircraft this would maybe not pose a problem because the signal is weak on the other side of the antenna, I am not sure. I could not glean any information on this mode beyond that it will sound if you are "below the glideslope" (varying frequency and loudness). There is no logic to check flap setting, rate of climb or anything else to suppress those for climbouts.That being said, I am only aware of one airport in Europe (LFML) that requires the DME off of an ILS for a SID - there used to be a departure out of Orly like 20 years ago...and then there are the Brits, of course .

We will use the new setting in planemaker that was enabled with 11.50beta11 that always "forces" experimental flight model on. I also like it.

Cheers, Jan

 

[Iain]

Thanks for the prompt feedback soon, will try and get some time on it tonight and give you some more feedback.  

[Hullu-poika]

9 hours ago, Iain said:

...pulled gently back at Vr, nothing..pulled harder, and maybe at 160kts she became airborne.   Strange...as never had that before.  

I am afraid it is because of experimental flight model setting. I also noticed that you have to pull much harder now than before... and it is impossible now to maintain the constant pitch rate without sufficient pushing the yoke back to neutral.

No idea whether it is closer to reality or not. But it is different.

Edited June 26, 2020 by Hullu-poika

[Iain]

I think that flight was maybe my first with the flight model enabled, I usually pull near full stick to get the nose moving then it requires very little back stick to get it to continue to pitch, then another pull to get it through the dead zone just at liftoff, will try again soon, not enough time to try it tonight.

[Iain]

Hi Jan, here is some feedback on some of the points I brought up.

- ZFW/GW, I managed to reproduce this problem.  For my flight tonight, EGNX to EDDF, West Atlantic, I had 17 tonnes of cargo and 7 tonnes of fuel.  ZFW was 50.3, GW was correct in the FMC at 57.3, I flew the route, landed, taxi to the cargo ramp and shutdown to a turnaround state.  Fuel remaining was 3.3, GW was showing as 54.3, I expected 53.6 but this is just a small error for whatever reason.   I then open ground services, fuel to 7.0 for the return leg, make ZFW 51.3 (cargo load of 18, (I'm using 33.3 as empty weight)), and click instant.  I now have 7.0 showing total in the fuel gauges.  I go to init ref, put in 51.3 in ZFW, and GW changes to 55.3 in the FMC, the ground services box is showing 58.3 as it should be.To solve this, I go to preflight, turnaround, apply, then put the ZFW into the FMC as 51.3, and GW in FMC now shows correctly at 58.3.  So it seems the FMC is making a miss calculation after refueling, but only after a flight is completed (since I tried to refuel before the flights and tried various fuel loads etc but it always worked).

- I still have the throttle issue, when descending with AT on and idle thrust to try and loose speed, my flight idle is around 28.  But the N1 is definitely influenced by my throttle position, the ghost throttles are at idle, if I leave my throttle forward I have about 31.  This also happens if I'm cruising with 60 N1, if I move my throttle forward it increases to 62, if I move it less, it drops to 58, even though the throttle isn't moving.  I can post a video later on this.  I don't have any plugins, just a standard CH pro throttle with no CH software running.

- ILS, I see these frequency being used for departure SID at many places, EGNX RW 27, EGPH 06 etc. I have a feeling putting it into Nav 2 instead of 1, gives the DME you need, but without the glideslope warning, needs more testing though.

- Vr pitch up, so this time I got the Vr and gave full back deflection, nose came up gently and a bit slow but was not a problem.  Really hard to tail strike, so that's a bonus, just seems quite different to before efm box being ticked, but more testing on this, I think I will probably prefer it.  Can also post a video.

Tonights flight was one of my most enjoyable, RW 27 at EGNX, 18kt cross wind, the aircraft is very controllable, no need for max rudder, needs left stick to keep the wing level though, on rotation the nose weather cocks to the left and you feel the crab....just amazing!  Same with the landing, have to work to hit the spot, will post my landing later once I do a small edit to shorten it.

Video will be online in 20 mins or so.

Cheers

Iain

Edited June 27, 2020 by Iain

[Iain]

Here you go Jan.

00:00- 01:00 the throttle topic

03:00-04:00 landing

05:50 FMC setup for return, ZFW/GW

https://youtu.be/OsNUio03e5Y

[Litjan]

Yeah, I see the throttle going up and down with your hardware throttle...could be due to the way we overwrite that value, not sure. Nils implemented that 10 years ago ;-) I think it is only like 2 percent - that will not amount to a whole lot of thrust. And if you don´t want that - don´t play with your throttles! ;-)

With your 1200fpm rate of descent the plane was still decelerating very slowly - as I would expect it.

Nice landing! :-)

I see the weight problem! Is that happening for you only on "second" flights? Or also when you initially set up your first flight? I just tried on my end (first flight) and it worked as expected, but if you say it happens on subsequent flights I will do one and check...

If all else fails, reboot gizmo before doing your return flight (little arrow on right-hand pop-out menu).

Cheers, Jan

 

[Iain]

Hi Jan

Throttles are no big deal, can easily live with that.

The weight problem is only on the second flight, I can’t produce this before the first flight.  I’m sure I have done a few legs in one sim session pre patch and can’t remember seeing this issue.  Will try a Gizmo reboot and see.  No big deal either but maybe something to add as a possible bug for a future patch.

and thanks for the compliment, I’m sure you have landed in EDDF at some point in your career?

[Litjan]

8 minutes ago, Iain said:

I’m sure you have landed in EDDF at some point in your career?

Oh, only about 5000 times...

Yep, I will definitely try to reproduce that weight bug - very likely it is one variable that is not reset... thanks for the report!

Cheers, Jan

 

[dr_anthony]

On 6/26/2020 at 7:25 PM, Litjan said:

I have observed the glideslope warning, too.

No below g/s on takeoff in xp 10 version. Its only xp11 issue. In xp 10 all works fine.

[Iain]

Yeh, I just did an illegal takeoff from EDDF on the northern runway, 25R I think, the taxi over the autobahn with Aerosoft EDDF is great!  But I read a takeoff from there is VERY rare, but I was getting glideslope warnings on climb out for the ILS I used for landing, which was 25L, wasn't even close to it, not seen that before?

[Litjan]

Well, in theory the glideslope transmitter is creating a glideslope that looks like a very wide, flat (3 deg) funnel. It stretches out in all directions, even though the promulgation characteristic is strongest towards the approach side.

So it is not impossible to receive the glideslope in any direction of the antenna.

The Below Glideslope deviation alert (Mode 5) is armed when a valid signal is received and the radio altitude is less than 1000 feet.

The warning should be inhibited if the course selected on the MCP is differing from the IRS heading by more than 90 degrees.

Cheers, Jan