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P3D v4 Rudder control

DragonflightDesign

DragonflightDesign

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northernireland
Okay... having never done any FD before, I'm well aware that I'm in for a stupidly steep learning curve here. Up front: I've inherited a commercial project of a very large flying boat (Boeing B-314) when the original FD designer was unable to complete for personal reasons. In general, his FD and .cfg files are around 99.9% complete, but beta testing has brought out a problem with on-water manoevers with the rudder. Basically, the aircraft reacts way too quickly for its size and weight (42 long tons). Where would I start to look to decrease rudder authority on the 'ground' but without changing the current flight characteristics?
 
Hi,

I have no competency in these domain - and a lot of other ;)

Just want to say I am so happy to learn that this B-314 project is still alive !
Thanks to take over

Gérard
 
It could be the rudder is overpowered or it could be the moments of inertia are too low
The answers will be in the .air file or the aircraft.cfg file.
Looking at the aircraft.cfg first because it is more understandable:
Find [weight_and_balance]

These are the numbers for the stock C-130 which would be a good starting point
empty_weight_pitch_MOI=4000000
empty_weight_roll_MOI=4500000
empty_weight_yaw_MOI=6500000
You could adopt these and see how it behaves differently then play with the yaw value.
Look at the contact points, if these are very close together they will resist airplane yaw less.
If you have an entry for Steering Angle, try reducing it.

In the air file there is a coefficient for Cn_dr Yaw Moment Rudder which is the strength of control.
Depending on the antiquity of the air file it will either be in Section 1101 (older systems) or 1544 as Cn delta rudder. For land airplanes that would be something like 0.1, you could halve it and see if the change in rudder control is helpful.

To open the air file you need something like AircraftAirfileManager.
Let us know how you get on with these steps
Roy
 
Thanks Roy. Something else on this project has reared an ugly head so it will be a few days before I can get back to this.
 
Dai,
Took a look at something with the morning coffee, :coffee: it has always intrigued me. :stirthepo
Why are there these variables? : (A:WATER LEFT RUDDER EXTENDED, unit) , (A:WATER RIGHT RUDDER EXTENDED, unit) & (A:WATER RUDDER HANDLE POSITION, unit) when there is only 1 command : (>K:TOGGLE_WATER_RUDDER)? Was thinking there was an omission in the SDK and tried some things such as WATER_RUDDER_SET and some other imagined things - heh.. OFC, nothing worked.

Then it dawned on me..
Forget the "visual position" of the water rudder and tune the position in the aircraft.cfg ( class 5 ) in [contact_points] so it is not so far away from the center datum?
The closer to the datum would result in less steering torque/force.

EDIT -
((( Rereading the original post perhaps this won't work since it is dealing with the "air" rudder, unless..
There is some code, somewhere, automatically dropping the water rudder ( unbeknownst to you ) when on the water.
 
Last edited:
DragonflightDesign said:
Where would I start to look to decrease rudder authority on the 'ground' but without changing the current flight characteristics?
Click to expand...
Don't have any aired etc. installed anymore, but you could limit the rudder deflection (dynamic pressure) at very low / taxi speeds.
 
Roman: those rudder commands are for the Beaver-type aircraft only where the main rudder is directly connected to the water rudder. On the B-314 the water rudder system is completely separate from the tail rudder. It was also almost completely ineffective; when the B314-A was built the water rudder was not included. The B-314s were upgraded to B314-A standard which, amongst other things, meant removal of the water rudder. Slow-speed on-water manoevering is done by differential throttle; the main rudder starts to bite at about 20kts IIRC (I'll need to look that one up again). When looking at an in-flight photograph of a 314 a fast check as to its type (original or -A standard) is to look for the water rudder.
 
Sure.. All true but.. Is there a non-visible water rudder declared in the aircraft.cfg? ( [contact_points] first digit a 5 )
Amphibs and flying boats are my favs. In all my aircraft the air rudder is more or less underpowered on the water but if the water rudder is down then way overpowered in yaw.
A quick check of the aircraft.cfg may prevent you from chasing down something that is hidden, causing all your woes.
 
Hi Dai,
I suppose you could go 1 of 2 routes..
1) comment out all the water rudder entries and renumber the entries so they are in order (if needed, point.0, point.1, point.2 etc) and be done with it.
-or-
2) yes, adjusting the longitudinal position (entry value #2) so it is closer to the datum ( 0 ) should allow you to fine tune yaw effectiveness on the water.
 
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