Default pitch of loaded aircraft

When loading a new aircraft especially mid-flight, sometimes it will either pitch-up or pitch-down violently from the last aircraft until I've spun the elevator trim control madly to get it under control. This is particularly annoying for TDS 737's.

I wanted to go through the TDS 737's with the FSX pitch control on zero and with full tanks.

So what is the first thing to edit in the aircraft.cfg to attempt to neutralize the pitch between these aircraft?

What you describe is because each type of aircraft has radically different lift characteristics, fuel placement, load amounts and placement and trim speeds. Changing planes in the air is the most dynamic altering environment you can create in the sim and there is no automatic compensation built into the sim. There is only one minor thing you can do if you insist in flying this way and that is to have auto-trim turned on and the auto-pilot engaged. If the new aircraft's trim rate is very slow and the new plane takes a long time to compensate for engine power and speed for trimmed flight, it will still take a while for the plane to recover, but the work load will be slightly less during the transition.

-Pv-

...I also wanted to leave the auto-trim off and auto-pilot off.

I wouldn't be surprised if the TDS 737's have incorrect information to begin with.

Surely there is something that I can edit to help balance these planes from one to another.

"Surely there is something that I can edit to help balance these planes from one to another."

No.

Doing this will make the aircraft fly incorrectly and no longer real world. You made choices demanding performance out of aircraft which are not possible in the real world ("auto-trim off and auto-pilot off") and expecting the sim to transform itself into an arcade game on demand.

Do this test:

In the FSX default 737 set up the plane in level flight. Inspect the artificial horizon. PAUSE. Switch planes and REMAIN PAUSED.

Inspect all the instruments including the artificial horizon.

-Pv-

I understand your reasoning about realism.

But let's assume that the aircraft geometry is wrong in the airfile or aircraft.cfg to begin with (knowing TDS) and needs SOMETHING edited to correct it.

EDIT: Ok -pv-, I'll try your test to begin with. However I'm doubting I will be able to detect any changes in the horizon gauge.

"I'm doubting I will be able to detect any changes in the horizon gauge. "

If this is the case, it's means the pitch at which both aircraft load is the same. This is a desired characteristic.

-Pv-

No, Mr. zippy, just the fleet of TDS 737-600 737-900 I have.

Seriously, it's not minor. One plane will fly relatively level and another will shoot straight down or up.

"I'm doubting I will be able to detect any changes in the horizon gauge. "

If this is the case, it's means the pitch at which both aircraft load is the same. This is a desired characteristic.

 

-Pv-

I still need to try this experiment out THANK YOU.

"One plane will fly relatively level and another will shoot straight down or up. "

This happens at load time because the ACTUAL FLIGHT SPEED when flight is resumed is not fast enough for lift. This causes the aircraft to stall (nose up) or fall out of the sky (nose down) and the pitch setting for these two aircraft are not the same. This is expected behavior. Because the pitch setting of the new aircraft is not set to recover from stall, the aircraft loses trim. No aircraft air transitioned loads resume flight at the previous flight speed. Not only do they load at a slower speed, the engines also have to spool up to flight power. All this time you are losing air speed until you have recovered power, speed and trim.

-Pv-

This is the best way I can visually describe using a Xbox 360 controller with NO trim adjustment.

1. Pitch is centered (Number 5)

2. Fuel tanks full

3. Half throttle

4. No auto-pilot

5. Plane loaded then allowed to stabilize. I have to hold the joystick to keep aircraft level.

Then slowly let the joystick go...

737-600

737-700

737-700 Cargo

737-800

737-900

737 MAX7

737 MAX8

737 MAX9

600 is like a Kamikaze so will be the first to try to fix!

All aircraft do not fly level at all speeds and altitudes with zero pitch trim. Suggest looking up the trim stats for the plane. At any desired speed and weight, trim the plane for zero pressure on the stick. That is the trim the model is designed to fly at.

So far, you have not reported the results of the test I prescribed using the exact procedure I suggested. Do that and type the result here.

I strongly suggest enabling auto-trim and carefully observing where the auto-pilot sets the trim while flying level. Observe that as you change speed, altitude and weight (fuel load) the trim will change radically during the flight. Observe this over many flights and flight conditions. At full fuel, ALL planes require a LOT more up trim than when nearly empty. The faster you go, the less trim is required because you have more lift available. The higher you fly at any given weight, the more trim is required because of thinner air. As the flight progresses, you burn off fuel which lowers the trim requirement. Maintaining manual trim is an art requiring a lot of practice and understanding the delicate balance of weight, speed and density of the air. All three of these things are changing constantly. Most airliners will use near zero trim near reserve fuel weight at cruise attitude and speed.

-Pv-

dogdish - Interesting, I'm watching wondering what the results might be! And I do like all the screenshots of the jetliners you used in the thread!

Good project for you, it will keep you out of trouble, for sure!

Rick :cool:

Hey Rick!

There were two solutions I found...

-Pv- mentioned a 'autotrim' setting, however I didn't see it in the FSX settings menu :confused:

So I searched Google and discovered it's in the FSX.cfg under [Realism] settings. Default is 'False' so I changed it to 'True'. It works great. You can see the trim wheel spinning on it's own and the aircraft no longer does a nose dive. You can still descend/climb OK.

However it affects ALL aircraft, that I didn't want so I change it back to 'False'.

NASA Tested!!!

Also found 'FSX Automatic Elevator Trim Gauge' (fsxatrim.zip by Chuck Dome) here in the FlightSim library. It works almost the same except you can manually move the trim wheel. As soon as you move the elevator again, it resumes working. I'm only going to use it for these TDS 737's so I don't have to keep cranking the trim wheel when switching a model.

"I'm only going to use it for these TDS 737's so I don't have to keep cranking the trim wheel when switching a model. "

Change aircraft on the ground while parked and trim for take off and this problem will go away.

-Pv-

Hey Rick!

 

There were two solutions I found...

 

-Pv- mentioned a 'autotrim' setting, however I didn't see it in the FSX settings menu :confused:

 

So I searched Google and discovered it's in the FSX.cfg under [Realism] settings. Default is 'False' so I changed it to 'True'. It works great. You can see the trim wheel spinning on it's own and the aircraft no longer does a nose dive. You can still descend/climb OK.

 

However it affects ALL aircraft, that I didn't want so I change it back to 'False'.

 

NASA Tested!!!

 

[ATTACH=CONFIG]204487[/ATTACH]

 

Also found 'FSX Automatic Elevator Trim Gauge' (fsxatrim.zip by Chuck Dome) here in the FlightSim library. It works almost the same except you can manually move the trim wheel. As soon as you move the elevator again, it resumes working. I'm only going to use it for these TDS 737's so I don't have to keep cranking the trim wheel when switching a model.

Okay, I'm a little slow today, where did you find this FSX.cfg and [Realism] settings. Not interested in making any changes, I'd just just like to see it and know where it is.

Thanks - Rick

...and this problem will go away.

-Pv-

Really? As your extensive lesson pointed out, elevator trim must be continually adjusted during flight to compensate for fuel burn, speed etc.

However, Chuck Dome's gauge was the answer I was looking for so I consider this closed.

Okay, I'm a little slow today, where did you find this FSX.cfg and [Realism] settings. Not interested in making any changes, I'd just just like to see it and know where it is.

 

Thanks - Rick

In Windows 7 it's under C:\Users\\AppData\Roaming\Microsoft\FSX

Wow, I never knew that was there and yes mine was also set at "False"

Thanks! Rick :cool:

The easy way to switch AC in air is to put it slightly nose up. Pause the Sim. Load the new AC. Wait 20 seconds as the Sim 'digests' the new parameters. Unpause Sim. And for crying out loud - do this at a higher elevation and you might not even notice anything.

There is another way. Quick & Dirty. Press 'Z' key (AP 'ON') then 'Cntrl+Z' (Alt Hold at present Alt). WAIT (20 SECONDS) FOR IT TO STABILIZE! (This is 'automatic' pitch trim in disguise! Ha). Go switch AC. When IT stabilizes press 'Ctrl+Z' and then 'Z'. You are DONE!

Chuck B

Napamule

...And for crying out loud - do this at a higher elevation and you might not even notice anything.

 

Chuck B

Napamule

LOL.. That would explain the long swath I left through the trees on the side of the mountain during testing ;)

Wow, I never knew that was there and yes mine was also set at "False"

 

Thanks! Rick :cool:

Just be careful and don't mess with the file too much Rick it's critical. If you delete it, it will rebuild again but you can lose custom settings. Don't want to hear you had to restore from back up again :)

Just be careful and don't mess with the file too much Rick it's critical. If you delete it, it will rebuild again but you can lose custom settings. Don't want to hear you had to restore from back up again :)

I'm telling you what, Jack! That new external HDD and Acronis system has "saved my keesh" on more than one occasion! One time, I lost "the big one," SIM OBJECTS, . A couple of weeks ago, my AUTOGEN went missing. Well worth the time and money!

No, I don't plan on messing around with what you discovered today!

Have a nice day! Rick

You're having fun with this and that is 'ok' I guess. My question is: What happens to all the passengers when you switch AC? The 'point' is you do not/can't just switch planes in mid air in 'real' life so why would you want to do it in the Sim? So you can post (sneak) Screenies of your fleet? Just saying...

Chuck B

Napamule

Change aircraft on the ground while parked and trim for take off and this problem will go away.

+1

Wim