Steering Angles

Tom Clayton

Tom Clayton

Administrator
Staff member
With the impending update set to wipe out my Official folder edits, I decided to document my updated steering angles to avoid having to do the math again. Then I figured since I had it all in one place, I might as well share it for anyone else that wants it...

Caravan, 60
Bonanza ,55
Cap 10, 70
DA40, 50
DA62, 50
Extra, 75
Icon, 50
King Air, 55
TBM, 50
XCub, 70
 
It's the angle from zero degrees in either direction that the nose/tail wheel will turn to steer the plane on the ground. Several planes have stock angles that don't allow for much in the way of maneuvering. It's part of the Contact Points section in the flight model cfg file. The stock C172 only has a steering angle of 15°, and differential braking isn't available, so ground handling requires a lot of space. In the real world, that 15° deflection may be close to the way the plane is built, but that doesn't count the spring loaded deflections that are available when the pilot uses differential braking. In order to get tighter ground handling in the sim, the steering deflection has to be raised, and differential braking has to be set in the systems file, which is just a 0-1 switch. For some silly reason, MS/Asobo seem to think that tricycle planes have solid axle between the mains.
 
Bingo! No diff. steering. Hate it!! I am starting to explore the files now and look for things that look familiar. I just make backups and then jump. :)

Don BP;)
 
Hi,

Made also this mod on the aircraft i mostly fly. Simply do not get how this got through the BETA-test (or was ignored). Didn't they taxi with the aircraft? :biggrin-new: :very_drunk:

Marcel
 
Bushpounder said:
Bingo! No diff. steering. Hate it!! I am starting to explore the files now and look for things that look familiar. I just make backups and then jump. :)

Don BP;)
Click to expand...

Brakes are in the Systems file and contact points are in the flight model. I don't know why they couldn't just keep things together like previous platforms, but at lease the files have less to scroll through.
 
Great idea!

Thanks, Tom! I screwed around with the various parameters in the C172 model trying to fix this, before. The C152 seems to be ok pretty much the way it came, don't you think?


Tom Clayton said:
With the impending update set to wipe out my Official folder edits, I decided to document my updated steering angles to avoid having to do the math again. Then I figured since I had it all in one place, I might as well share it for anyone else that wants it...

Caravan, 60
Bonanza ,55
Cap 10, 70
DA40, 50
DA62, 50
Extra, 75
Icon, 50
King Air, 55
TBM, 50
XCub, 70
Click to expand...
 
I just wanted to add a couple of notes to Tom's post.

1. Being kind of ignorant in most of this flight-simming business (no real-world piloting experience), I read somewhere that many light aircraft with differential braking are capable of ground turning angles approaching 90 degrees. So, I took the liberty of changing my C152 and C172 contact point 0 from 15 to 90 with a very satisfactory result.

2. I do NOT have rudder pedals, so as Tom suggested I also changed systems.cfg for each aircraft to: differential_braking_scale=1.
3. I can not speak to how any of this effects MSFS simmers who have rudder pedals in their simulator set-ups.
 
RRD2 said:
Thanks, Tom! I screwed around with the various parameters in the C172 model trying to fix this, before. The C152 seems to be ok pretty much the way it came, don't you think?
Click to expand...

I haven't flown it enough to really say, but if it's anything like the 172, it could be tighter, but even enabling diff braking would be a major improvement.

RRD2 said:
I just wanted to add a couple of notes to Tom's post.

1. Being kind of ignorant in most of this flight-simming business (no real-world piloting experience), I read somewhere that many light aircraft with differential braking are capable of ground turning angles approaching 90 degrees. So, I took the liberty of changing my C152 and C172 contact point 0 from 15 to 90 with a very satisfactory result.
Click to expand...

Turning the steering line past either of the main gear just results in scrubbing the wheel sideways. Imagine a line between the main and nose/tail. An angle perpendicular to that line should be your max angle. If you want that exact angle, it will take a little high school trig. I'm attaching a simple spreadsheet I built to do the math for me. In the longitude box, you want the difference between the nose/tail gear and the main longitude values. For example, the difference between 2 and -5 will be 7, not -7. For latitude, use the positive side. The "Both Please" will be in the result field serving as an error handler (div by zero) until there's something in the longitude field.

On a side note, a few of the planes, including one or two tricycle planes, have the steering set to 180°. This is actually a throwback to at least FS2002. That angle is a switch that disables active steering and converts the gear point to a castor.
 

Attachments

  • Steering Calculator.zip
    6.5 KB · Views: 6
Tom, I am blown away with your technical understanding of aircraft geometry! I followed you all the way past " imagining a perpendicular line", etc. but got no further. :untroubled: That
really helped me understand the wheel scrubbing issue you refer to. The spreadsheet not withstanding, I fully trust your math, however, and will just re-adjust my point 0's to the numbers you recommended in your original post. Great stuff and I thank you for that!

BTW, after further experimentation, I agree that the C152 "straight out of the box" is badly out of whack, too. I found it almost impossible to make a 360 degree turn at Bugalaga Air Field!

Will try to attach a Google Drive link to a fun video I made awhile back for my brother, that demonstrates that issue. (Hope that's "legal", here...)
Thanks again!

https://drive.google.com/file/d/1bVM_-F-oeDdPuDilfzcvy33junCWM82W/view?usp=sharing
 
RRD2 said:
Tom, I am blown away with your technical understanding of aircraft geometry! I followed you all the way past " imagining a perpendicular line", etc. but got no further. :untroubled: That
really helped me understand the wheel scrubbing issue you refer to. The spreadsheet not withstanding, I fully trust your math, however, and will just re-adjust my point 0's to the numbers you recommended in your original post. Great stuff and I thank you for that!

BTW, after further experimentation, I agree that the C152 "straight out of the box" is badly out of whack, too. I found it almost impossible to make a 360 degree turn at Bugalaga Air Field!

Will try to attach a Google Drive link to a fun video I made awhile back for my brother, that demonstrates that issue. (Hope that's "legal", here...)
Thanks again!

https://drive.google.com/file/d/1bVM_-F-oeDdPuDilfzcvy33junCWM82W/view?usp=sharing
Click to expand...

To help illustrate the effect of changing the C152 from 15 degrees to 60 degrees, I have taken the liberty to upload today's update to my previous video at Bugalaga Air Strip.
https://drive.google.com/file/d/1sK__xZnc1heH3aNX3XjY-f3HWJbTTH4J/view?usp=sharing
 
The math isn't that hard as long as you remember how to use a scientific calculator and use the tangent functions. Mrs. Morris taught us a mnemonic back in high school: SOH CAH TOA. That last part stads for "The Tangent of the angle is equal to the Adjacent leg divided by the Opposite leg." So do the division, then use the inverse tangent function on the calculator. I'm 55 and I still remember it like it was 1980!
 
78, here. I do remember SOH, CAH, TOA, but haven't used them for at least as many years as you've been on earth. LOL
 
For anyone not familiar with them, the contact points are a throwback to at least FS9, so it's the 8th value on the gear point that defines the steering. (Technically, it's parameter #7, but they start at zero.) I still have the FS9 Aircraft Container Word document. If anyone wants it, let me know. It still has a few useful sections.
 
Well, now that the November 24th update is out I can confirm that Tom's original reason for this thread is definitely valid.
It changes all the Contact Point 0s back to their original settings.

So, if you like to have better ground/taxi maneuvering on your aircraft it's great to have Tom's recommended settings on hand to reset that 8th value in the Contact Point 0.
 
The Icon has a couple of points before the first gear. Point.2 is the nose wheel. And I'm also playing with that plane's steering angle a little. I think 50° may be a bit much with such a short wheelbase. I'm going to try 45 for a bit.
 
MSFS Steering Angles

Tom Clayton said:
With the impending update set to wipe out my Official folder edits, I decided to document my updated steering angles to avoid having to do the math again. Then I figured since I had it all in one place, I might as well share it for anyone else that wants it...

Caravan, 60
Bonanza ,55
Cap 10, 70
DA40, 50
DA62, 50
Extra, 75
Icon, 50
King Air, 55
TBM, 50
XCub, 70
Click to expand...

Hey, Tom.

I have used your recommended settings ever since you first posted them here.

Several MSFS updates later, they certainly have come in handy, but as you alluded to in your original post, they do get re-set frequently by those updates.

I'm just curious.

Have you possibly developed a macro or script file of some kind to automatically put these settings back to your recommendations, to preclude
having to do this manually after every update?
 
I wish. I still need to go back and re-do some of the ones in this list again. Luckily, it only takes a few seconds for each one.
 
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