FSX TDS Reverse Thrust Problem

[SEA747]

I've tried to figure out how to make the TDS aircraft I have be able to reverse. Even when it clearly shows the throttle panel with the levers reversed and the animations on the aircraft shown, the aircraft doesn't move anywhere. I've checked the aircraft.cfg file, but everything for reverse throttle is correct. I did alter the aircraft files to include other panels and virtual cockpits. Does anyone know the problem with this?

 

Aircraft included:

TDS Boeing 737 MAX 8

TDS Boeing 787-8 (RR)

TDS Boeing 787-9 (GE, RR)

 

Computer specifications:

Lenovo ThinkPad T430

Intel Core i7-3520M @ 2.90GHz

1600x900 14.0-inch LED display

250GB SSD

8GB RAM

Windows 10 Pro x64

Intel HD Graphics 4000

[il88pp]

Two thoughts, no .cfg changes.

Reduce weight by unloading fuel. (default 737 won't reverse with full fuel either.)

2. Check parking brake not set. (yeah, I know..)

[PhantomTweak]

The secret to getting the reversers in FS (both 2004 and X) is to wait till all 3 gear (two mainmounts and the nose) touch down, hit F1, the tap F2 over and over. When you want them off again, tap F1 again.

Works every time. Give it a shot. Can't hurt :D

Pat☺

[CptCaveman]

Reverse thrust is not a reverse gear. The aircraft is not supposed to go backwards in reverse thrust. It is only used to slow down after touchdown and should never be used under 60 knots.

 

There is nothing wrong with the aircraft.

[il88pp]

Lacking a pushback cart I sometimes use reverse to get out of a parking spot backwards.:)

I don't use much fuel usually anyway. I set "fuel flow scalar=" to 0.7 or so and the plane uses much less fuel per mile now. Keeping it green. ;)

[mrzippy]

I am getting ready to test the TDS 737 MAX 8. I did notice this in the README.

 

If you edit or replace the panel.cfg that is included in this package then your aircraft will not work properly. If you chose to use a different panel, you must edit the panel.cfg and include information from the TDS 737 panel folder and .cfg files.

 

TEST UPDATE: This TDS 737 would not move from my parking spot using reverse thrust, even with 10% fuel in each tank. Doing a high speed taxi test, the reverse thrust would eventually slow and stop the aircraft. My conclusion is very weak reversers. I took the .air file from my POSKY 737, renamed it and used it in the TDS. It works perfectly. Plenty of reverse thrust.

[snoman909]

Backing up a Falcon using thrust reversers and you get a nice vacation with no pay, that is if your caught :)

[PhantomTweak]

Lacking a pushback cart I sometimes use reverse to get out of a parking spot backwards.

Reverse thrust is not a reverse gear. The aircraft is not supposed to go backwards in reverse thrust.

Back in the "day", I would occaisionaly take a flight with my father up in the captains chair, in the old DC-8-62's. He loved those planes. Anyway, Once in a great while, if there was going to be an "unacceptable" (in his mind) delay in getting a pushback, he would just clear the ground crew away and throw 2&3 into reverse and back out. VERY gently mind you.

They don't ever do it anymore, because airports and the FAA tend to have several kinds of fits, and throw a few litters of kittens over it, but I distinctly recall a couple of episodes of it happening.

There may well be numerous interlocks preventing this from happening any more, as well as the design of the engines themselves, which would be damaged by such an act.

 

Just my 2 cents on it, is all...

Pat☺

[il88pp]

Yeah, it's not something I'd do in a real aircraft, but in fs(x) you have to make do sometimes..

[SEA747]

I am getting ready to test the TDS 737 MAX 8. I did notice this in the README.

 

If you edit or replace the panel.cfg that is included in this package then your aircraft will not work properly. If you chose to use a different panel, you must edit the panel.cfg and include information from the TDS 737 panel folder and .cfg files.

 

TEST UPDATE: This TDS 737 would not move from my parking spot using reverse thrust, even with 10% fuel in each tank. Doing a high speed taxi test, the reverse thrust would eventually slow and stop the aircraft. My conclusion is very weak reversers. I took the .air file from my POSKY 737, renamed it and used it in the TDS. It works perfectly. Plenty of reverse thrust.

 

Is the .air file the one included with the main file where the model, panel, sound, and texture folders along with the aircraft.cfg file are located?

[mrzippy]

Is the .air file the one included with the main file where the model, panel, sound, and texture folders along with the aircraft.cfg file are located?

 

You betcha, Red Rider!

[SEA747]

Well, tried it. Didn't work at all renaming the .air file from the POSKY 737-800 to the TDS 737 MAX 8. Still took around 30-45 seconds for the reverse throttle to take full effect for the 737 MAX 8 to slow down on landing. I don't think POSKY ever made a 737 MAX 8, did they? Also made sure parking brake was off when at the gates.

[mrzippy]

Well, tried it. Didn't work at all renaming the .air file from the POSKY 737-800 to the TDS 737 MAX 8. Still took around 30-45 seconds for the reverse throttle to take full effect for the 737 MAX 8 to slow down on landing. I don't think POSKY ever made a 737 MAX 8, did they? Also made sure parking brake was off when at the gates.

 

Spoilers engaged, flaps at 30 degrees or full?

[SEA747]

Spoilers engaged, flaps at 30 degrees or full?

 

No spoilers, but flaps at full. I probably should try landing with spoilers now.

 

EDIT: Well, I'm flying from Vancouver to San Diego with nine stopovers in between with a 787-9. I tried; even with spoilers, reverse thrust does not really make the aircraft (both 737 MAX and 787) slow down faster than without them.

[mrzippy]

No spoilers, but flaps at full. I probably should try landing with spoilers now.

 

Yep, spoilers are a good thing! Set auto spoilers so you don't have to think about it while landing. Also, I would hope you are not trying to land with full tanks of fuel. I never did like the TDS737 or 787, but the 727-200 flies great!

[il88pp]

Here are two lines from the default 737_800 aircraft.cfg file:

 

in:

[GeneralEngineData]

min_throttle_limit = -0.25 //Minimum percent throttle. Generally negative for turbine reverser

 

and in:

[TurbineEngineData]

reverser_available = 1 //Thrust reverser available?

 

Is that (or with similar values) in the TDS you are looking at? (note the -0.25 is a negative value)

 

(Despite your first post I thought I should ask..)

[SEA747]

Here are two lines from the default 737_800 aircraft.cfg file:

 

in:

[GeneralEngineData]

min_throttle_limit = -0.25 //Minimum percent throttle. Generally negative for turbine reverser

 

and in:

[TurbineEngineData]

reverser_available = 1 //Thrust reverser available?

 

Is that (or with similar values) in the TDS you are looking at? (note the -0.25 is a negative value)

 

(Despite your first post I thought I should ask..)

 

Yes, I checked all three aircraft. All had similar values; I even edited them to the ones you showed. That still didn't help with the reverse throttle at all.

[il88pp]

what exact aircraft base package?

******.zip filename

and site you got it from please.

 

What vc's and panels did you use?

 

Is the problem there with all VC's ?

Also reverse problem with original VC?

[SEA747]

what exact aircraft base package?

******.zip filename

and site you got it from please.

 

What vc's and panels did you use?

 

Is the problem there with all VC's ?

Also reverse problem with original VC?

 

It's hard since I combined multiple .zip files to place them under the same aircraft. I did make sure the basic information for the liveries were the same. As for the basic packages:

tds_b737max8_base_package.zip from FlightSim.com

tds_boeing_787-800_rr_mega_pack_fsx_p3d.zip from Rikoooo

tds789trent_boeing_n789ex.zip from PerfectFlight

 

All 787 types were replaced with AeroSim's 787 VC and panels. The 737 MAX 8 was replaced with the default FSX 737-800 VC and panels.

 

The problem applies to all TDS aircraft I've downloaded, and the reverse problem applied to the original files (well, all the aircraft had non-workable panels and no VC at all.)

[il88pp]

I downloaded the:

tds_b737max8_base_package.zip

I made the changes to it as in the readme.

(replace panel folder with the one from the 737_800, and then place files in model, panel and sound, from folder 'FSX', into the aircraqft)

 

Then installed.

5% fuel, parked, and full reversers. No movement backwards.

 

Then started editing the aircraft.cfg file.

------------------------------------------------------------

 

Canges to TDS aircraft.cgf

To create reverse thrust.

 

You need to know that anything after // wil be disregarded by FSX and will not be loaded.

(It's makes it a 'comment', so you can add

info/instuctions and remember what you changed.)

 

-----------------------------------------------------

I reduced aircraft weight. I just guessed at it.

 

I removed "bypass ratio", looking up the info on the aircraft.cfg file and the things that can be in it, this parameter was not in the list there.

https://msdn.microsoft.com/en-us/library/cc526949.aspx

 

I changed static pitch from -0.1 to 0.0 ---- an aircraft leaning forward will not back up easily I think. Seems like you would be going uphill backwards.

 

But I'm not sure on that.

||||

I also lifted the nosewheel out of the ground, changing contact point point.0

 

It now went backwards with 10% fuel. But very very slowly.

Then I tried increasing thrust, by changing

rated_N2_rpm =

But that had little or no effect.

 

Then I tried changing

thrust_scalar =

that worked.

 

------------------------------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------------------------------------------------

With the following changes, the aircraft moves backwards slowly at 66% Fuel.

At less fuel it will move back faster.

 

The main difference was made by increasing "thrust_scalar = "

 

This will increase forward thrust as well of course.

It will affect acceleration, and also perhaps affect how well the aircraft follows a glideslope.

 

I did not check stopping power. Did not do a flight. I only put it on a runway, and used reversers to taxi backwards.

------------------------------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------------------------------------------------

[WEIGHT_AND_BALANCE]
max_gross_weight = 181200
empty_weight 	 = 70000  //orig 92500 //changed by il88pp


[TurbineEngineData]
//bypass_ratio          = 9  //--Switched off by il88pp


'cosmetic' change, taking nosewheel out of the ground:

[contact_points]
//point.0  = 1, -13.39,   0.00, -8.39, 1600, 0, 1.11, 75, 0.35, 2.89, 0.85, 6.0, 6.0, 0, 206.8, 281.6	//Nose
point.0  = 1, -13.39,   0.00, -9.00, 1600, 0, 1.11, 75, 0.35, 2.89, 0.85, 6.0, 6.0, 0, 206.8, 281.6	//Nose //increased height -8.29 to -9.39 //il88pp

//static_pitch     = -1.0
static_pitch     = 0.0   //orig -1.0 //changed by il88pp


[jet_engine]
thrust_scalar 	      = 1.3   //orig 1.0 //changed by il88pp

------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------------------

These are just some quick guesses.

point.0 fits ok,

I don't really know what difference static pitch makes.

 

The other values may be a bit high or low, adjust to your liking.

------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------------------

The aircraft has many more problems.

Check the fuel and payload menu and you see the weight center of gravity is way forward, in the nose. I think that will cause issues with stability.

 

 

I also noticed some commands don't work anymore. , fuel dump on my system, does not do anything.

(Just realised, It could be the aircraft has simply no fuel dump modelled. No idea how to add that if that's the case.)

 

I've tried TDS aircraft before, and never got anywhere with them. VC's give weird eyepoints, there are weight and balance problems, and more.

It sounds like you got it flyable at least. Good on you, and good luck with it.

 

I won't be trying the other files you listed, but I think the fix for reversers will be similar.

[mrzippy]

I just flew the TDS 737 MAX8 from KFAT to KSFO. No modifications to the aircraft including not putting in the FSX stuff. Other than the takeoff roll being WAY to long (as usual for TDS 737s) the flight was uneventful. I landed at KSFO with 20% fuel in all tanks, 30 degrees flaps, spoilers activated, landing speed at 138 knots. Reversers did their job and I slowed to under 60 knots within 20 seconds and took the first runway turnoff.

 

SEA747, you never stated your landing speed and I already know of your lack of spoiler use.

[il88pp]

After your post I gave that a try too. Not putting in the FSX stuff or the default panel folder.

It would not taxi backwards. Reversers visible and audible, but no backwards movement. Even at 0% fuel.

[PhantomTweak]

It now went backwards with 10% fuel. But very very slowly.

Then I tried increasing thrust, by changing

rated_N2_rpm =

But that had little or no effect.

 

Then I tried changing

thrust_scalar =

that worked.

 

Changing the rated_N2_rpm = line only changes the max RPM of the engine, not thrust. You can probably look it up online easily enough. The 29920 value is the default MSFS value, but you can change it to the "real" value or not, as you choose.

 

As I mentioned, without getting into the .air file changing the thrust_scalar = line is one way to affect thrust in the aircraft.cfg file. The line static_thrust = in the [TurbineEngineData] section, which can also be changed to the real-world value easily enough, is the real key value.

 

Please note that "The thrust_scalar parameter scales the calculated thrust for jet engines (thrust taken from the [TurbineEngineData] section)." and it specifies that it is the "Parameter that scales the calculated thrust provided by the propeller."

 

To make the engines function exactly like the "real world" engines do, a great deal of mathmatics and editing of the .air file are what's really needed. The FSDevelopers Forums have reams of "How-to" threads just on Jet engine thrust, and what effect different variables have on it, such as altitude, airspeed, OAT, RPM, fuel flow, etc, etc ad nauseam.

 

Me, I do play in the air file a lot, and getting jet engines just right at all altitudes and airspeeds is a real adventure. Same for fuel consumption, Maximum velocity at altitude, you name it.

 

Does this help any?

Pat☺

[il88pp]

Thank you Pat.

I usually use thrust_scalar

Not saying that is the correct way, just my preference.

Reason is it is a parameter that can be used with all types of aircraft.

Other reason is it is a small number, and I find it easyer to make small changes to then to the 5 digit value for static_thrust. Easyer to keep an overview.

 

Prop planes have different engines, and those don't have the static_thrust line. You really have to know your engines to make any good changes to that.

I can sometimes figure that out, after a lot of trial and error, but it's hard to get it just right.

Much easyer for me to simply change thrust_scalar.

 

Also, I think of it as a percentage.

1.0 is 100%

1.05 is 105 % and increases thrust by 5%

 

I agree, it's not "the right way". But it does simplify things.

The .air file I avoid until absolutely necessary. (I once made a car fly, but that's it)

Maybe I should us AirEd a bit more often.

 

I'll remember your post next time.:) Thanks.

[PhantomTweak]

Also, I think of it as a percentage.

1.0 is 100%

1.05 is 105 % and increases thrust by 5%

That is actually 100% correct :D Pun intended :p

 

Prop planes have different engines, and those don't have the static_thrust line. You really have to know your engines to make any good changes to that.

Changing that can get a bit more complex, believe it or not. The biggest trick for prop planes is the power_scalar =1.000 line, closely followed by the lines

cylinder_displacement= 100.000

compression_ratio= 8.500

max_design_mp= 38.000

The line max_rated_hp= 285.000, believe it not, really seems to be mostly for the sound envelope.

 

Don't get me started on the propeller section! THAT pretty much gives me a headache :D

 

Whatever works best for you is the right way, I always say :)

I'm just offering small suggestions, to try and grease the skids, as the saying goes.

Pat☺