FR Super Cub problem taxiing on bush strips

[fliger747]

Nose up trim from landing? Super cubs require a bunch of nose down trim cranks with flap extension from the initial descent approach settings, however this usually ends up somewhere near the appropriate takeoff trim. Any load is distributed aft, also requiring more nose down trim. This can be a lot but since the stab is trimmed and full elevator is still available reasonable good pitch control is retained. Probably because of the thick airfoil cubs still seem to have good pitch stability at aft CG locations. Some of the high HP (heavy engine) planes can be a bit fwd CG when empty.

An AOA indicator is available for about $1400, thinking of getting one as the plane usually has a lot of flying left at an IAS of 40 mph, which is the point at which the AS indicator really loses interest. Not so important for float flying, so much cub flying is about how it feels, which is hard to replicate in FS.

Still fun planes! T

[mike_cyul]

Given that FSX aircraft are fundamentally all identical when it comes to the gear animations and contact points (it's really just a matter of putting in the correct numbers to get the location, appearance and movement you want), I'm wondering if there isn't something else to try: suspension, gear travel, damping, etc., are one thing, but what about the scrape points?

I can't replicate this problem, and neither can anyone else I've asked (and I think there's only been two reports to Support in total), but as it's seems pretty likely a simple conflict somewhere between aircraft and terrain meshes, why not try, just as an experiment, to swap out the scrape points (usually point.3, on down, for the taildragger) with an aircraft or similar size that works? Just to see if the conflict is still there. Of perhaps even try taking out the scrape points entirely. Perhaps one is dragging too low for the terrain mesh altitude or something similar?

Mike

[HighGround22]

.
I'm fascinated with this thread, and I hate to be a stick in the mud, but . . . .

FWIW, I'm +1 with Griphos' problems. I have the FR Super Cub Ultra and had to stop flying it -- for the same reason as his: I wanted to use it as a bush-strip plane, but got frustrated with the aircraft "bogging-down" and/or thrashing itself to death.

Been doing this stuff since early FS9, so it was quite a surprise to see myself with so little control of an airplane, in the aforementioned instances.

After repeated tries, alas, I just found myself ignoring the plane.

[bstolle]

I've pm'd a few customes with this problem but apparently this doesn't happen with any default dirt strip, only orbx airfields. As I'm not using any of these anymore I can't test. Seems to be a very restricted mesh problem.
You can soften the shock absorbers almost indefinitely so that they always 'work' on any ground but especially the tundra wheels are very springy IRL.
It's simply impossible to set the damping correctly for all ground variations as FSX does apparently have serious problems with non-standard meshes.

[mike_cyul]

.
I'm fascinated with this thread, and I hate to be a stick in the mud, but . . . .

FWIW, I'm +1 with Griphos' problems. I have the FR Super Cub Ultra and had to stop flying it -- for the same reason as his: I wanted to use it as a bush-strip plane, but got frustrated with the aircraft "bogging-down" and/or thrashing itself to death.

Been doing this stuff since early FS9, so it was quite a surprise to see myself with so little control of an airplane, in the aforementioned instances.

After repeated tries, alas, I just found myself ignoring the plane.

Try the scrape points as mentioned above. It has to be something pretty simple.

[HighGround22]

Try the scrape points as mentioned above. It has to be something pretty simple.

Yeah, Mike, that's my sense of it.

I'll have a boo at yon points.

Anon.

[griphos]

Yeah, I'll try that too. It will be this weekend before I have time, but I'll report back.

It could be mesh problems with Orbx, in particular, I suppose, but I suspect that the Orbx backcountry airfields I'm flying to are really just terrain without any leveling or other airfield adjustments. It might be worth trying to land the Super Cub away from airports in non-Orbx terrain to see if the the problem can be replicated there.

[fliger747]

The springiness of bush wheels (Ok I run Goodyears..) varies a lot with air pressure. The lower the pressure the more bean bag like. Less springy and better surface flotation, but more rolling ristance. Contact points cannot makeup for terrain mesh errors. You might try changing the mesh resolution in the display parameters. If The contact points work OK on the various default surfaces, that' about all the designer can do.

T

[mike_cyul]

It might be worth trying to land the Super Cub away from airports in non-Orbx terrain to see if the the problem can be replicated there.

We did a great deal of the testing (especially the Extreme and Bush aircraft) on non-airport mesh, all over the FSX world, as it was pretty obvious that's where users would be flying, and didn't have any problems (and to date, it appears neither has anyone else). Then again, the aircraft were also flown from Orbx airports (I have Australian and North American airports on my computer) without issue, too, so who knows!

Mike

[griphos]

<snipped irrelevant="" stuff="" about="" actual="" plane=""> Contact points cannot makeup for terrain mesh errors. You might try changing the mesh resolution in the display parameters. If The contact points work OK on the various default surfaces, that' about all the designer can do.

T

I don't even know what a "mesh error" would be. I'm not talking about abrupt changes in elevation. It's relatively flat land with dirt or grass runways on it. I use the mesh resolution that is stipulated by the scenery. Again, I don't have this problem with other aircraft I fly into these same strips.

I'll try using some settings from the other aircraft as a test, though, as I said.</snipped>

[olderndirt]

This from a forum member at 'Bushpounders Flying'. Certainly makes it turn.

"Well, slap my hand. I couldn't change the tailwheel because I was changing the wrong parameter! I no good way to modify .cfg files.
So. To make the tailwheel steerable with the rudder, in the [contact_points] section of the .cfg file, change the 7th entry of line point.0 from 180 to 60. (Example below) This changes the steering angle and the number is the deflection in one direction, so 60 means that you have 120° from full left to full right. The higher the number, the sharper the turn. I find that after 60, the steering gets too sensitive, but that's just me. 180 makes the wheel free castering.

[contact_points]
point.0=1, -15.85, 0.0, -1.05, 1800, 0, 0.256, 180.0, 0.07, 2.5, 0.5, 0.0, 0.0, 0.0, 0.0, 0.0"

[contact_points]
point.0=1, -15.85, 0.0, -1.05, 1800, 0, 0.256, 60.0, 0.07, 2.5, 0.5, 0.0, 0.0, 0.0, 0.0, 0.0

[fliger747]

Example of mesh errors, I remember flying a chopper about in the alps, some places the visual and hard deck do not coincide, the skids sinking into the terrain a foot or so. When developing contact points I always test a lot of places, I am sure Mike did this.

T

[fliger747]

Further point on tail wheel steering...

Though a cub has tailwheel steering, FS does not replicate it well. IRL it is through springs an is somewhat approximate and castors beyond a certain angle. Having periodically disassembled these tailwheels for cleaning and lube, they break free somewhere around 60 deg. FS steering is far too powerful and precise and does not break free.

My opinion as an experienced and current cub driver is that the 180 castoring CFG value best replicates the experience. Feel free to disagree.

T

[mike_cyul]

I've been talking with Wozza, who knows more about terrain mesh than I do, and one potential source for a problem could be that in FSX the terrain mesh loads after the aircraft mesh. In other words, it lags behind the aircraft mesh. This is why aircraft jump sometimes when switching views: the terrain comes up after the aircraft loads and hits the contact and scrape points. Not too sure if it applies directly here, but it does help illustrate that there are differences in behaviours between the two mesh types in FSX.

Another thing to try is increasing the Impact Damage Threshold (Feet Per Minute) in the contact points. This is the parameter highlighted in red below, on a [contact_points] line:

point.0=1, -15.85, 0.0, -1.21, 1800, 0, 0.256, 180.0, 0.07, 2.5, 0.5, 0.0, 0.0, 0.0, 0.0, 0.0

Try increasing this to a much higher number, such as 9000, and see if that makes a difference.


Mike

[dandog]

I99D is not a landing strip/field. It's a river bank. ANYTHING I tried load there on the "strip", sank into the ground. I think the campfire is the remains of a botched landing. The other nearby "landing areas" were not nearly as bad, I98D, I97D, and I96D. They were usable, needed full power and a prayer to move around, but do-able. IMHO, it is not an issue with the FR Cub, any of the different flavors, but the scenery.

Daniel.

[griphos]

I think the campfire is the remains of a botched landing.

Daniel.

:-)

That's pretty funny. As I've said a couple of times, I land in those places fine with other aircraft. So, it's not the scenery, I don't think.

[griphos]

Okay, I have a little time to test. So, to make sure I'm understanding, Mike suggested changing the scrape points. Am I right in understanding that to mean basically replacing point.3 through point.10 with the values from some other plane?

Bernt suggested changing the shock absorber settings. I can't tell from the key in the .cfg which contact points I would change to do that and what I'd change it to in order to soften them.

I tried changing the impact damage threshold to 9000 (from 2500) but that made no difference.

[griphos]

Okay, I swapped point.3 through point.8 with the ones in the Carenado C185 Tundra (it only went to point.8) since that was also done by Bernt (I have his latest .cfg file for that aircraft). The result is that it handles much, much better! I flew to about five different strips there around the Salmon river and she did well at all of them. There was only one incident of crazy gymnastics crashing like I usually experience, and that was at the first strip, Mile Hi (ID97) when I first tried to turn around at the top of the strip. Not sure what happened there, and I was worried, but I landed there two more times and taxied around. I landed at four other strips and taxied around. I never got stuck once, nor did I ever tip over again. I even took off at several strips without staying on the runway to see how it would do "off airport." It did fine.

Here are the original settings in the Experimental version:

point.3=2, -1.0, 17.0, 1.90, 2000, 0, 0.000, 0.0, 0.00, 0.0, 0.000, 0.0, 0.0, 5.0, 0.0, 0.0
point.4=2, -1.0, -17.0, 1.90, 2000, 0, 0.000, 0.0, 0.00, 0.0, 0.000, 0.0, 0.0, 5.0, 0.0, 0.0
point.5=2, 5.4, 0.0, -2.45, 2000, 0, 0.000, 0.0, 0.00, 0.0, 0.000, 0.0, 0.0, 6.0, 0.0, 0.0
point.6=2, -15.38, 0.0, -1.00, 2000, 0, 0.000, 0.0, 0.00, 0.0, 0.000, 0.0, 0.0, 9.0, 0.0, 0.0
point.7 =4, 0.95, 2.75, -4.55, 4200, 0, 0, 0.0, 0.3, 2.5, 0.90, 0.0, 0.0, 3, 0, 0
point.8 =4, 0.95, -2.75, -4.55, 4200, 0, 0, 0.0, 0.3, 2.5, 0.90, 0.0, 0.0, 3, 0, 0
point.9 =4, -1.0, 17.0, 1.90, 1600, 0, 0, 0.0, 0.0, 0.0, 0.00, 0.0, 0.0, 5, 0, 0
point.10=4, -1.0, -17.0, 1.90, 1600, 0, 0, 0.0, 0.0, 0.0, 0.00, 0.0, 0.0, 5, 0, 0

I left point.9 and point.10 unchanged (since the C185 didn't have those). They are Max/Static Compression and Damping ratios.

Here's what I put in from the C185:

point.3 = 2, -4.60, -17.0, 3.28, 1500, 0, 0.00, 0, 0, 0, 0, 0, 0, 5, 0, 0 //LW
point.4 = 2, -4.60, 17.0, 3.28, 1500, 0, 0.00, 0, 0, 0, 0, 0, 0, 6, 0, 0 //RW
point.5 = 2, 1.2, 0.0, -2.2, 1500, 0, 0.00, 0, 0, 0, 0, 0, 0, 9, 0, 0 //tail
point.6 = 2, 1.2, 0.0, -2.2, 1500, 0, 0.00, 0, 0, 0, 0, 0, 0, 4, 0, 0 //Fslg
point.7 = 2, -18.75, 0.0, 6.45, 1500, 0, 0.00, 0, 0, 0, 0, 0, 0, 7, 0, 0 //Aux1
point.8 = 2, -14.12, 0.0, 0.01, 1500, 0, 0.00, 0, 0, 0, 0, 0, 0, 8, 0, 0 //Aux2
point.9 =4, -1.0, 17.0, 1.90, 1600, 0, 0, 0.0, 0.0, 0.0, 0.00, 0.0, 0.0, 5, 0, 0
point.10=4, -1.0, -17.0, 1.90, 1600, 0, 0, 0.0, 0.0, 0.0, 0.00, 0.0, 0.0, 5, 0, 0

You can see almost every value is different. I have no real idea what any of this means. I'm not sure if any of this would make the Super Cub unfaithful to RL. But it does seem to work. The plane sits correctly on the ground from outside view every time I checked.

I'll keep experimenting with it, but it's nice that perhaps the plane will now work for the purpose for which I bought it.

[Roger]

Heck of a strip I99D! I tried a tundra tyre version and the only problem I had was with negotiating the runway's slopes in both axes:

[griphos]

Yes, there's not that much slope there, though, really. Most planes I fly there don't have an issue with it, and the Super Cub doesn't either with the new contact points.

[Vox]

This is all getting more and more interesting! :-)

I'll surely try the scrape points and the impact damage threshold mods (even if I'm always testing without switching between views and it doesn't make things better) but, as for the orbx and other custom mesh and terrain discussion, I'd like to point out again that A2A's Cub rolls smoothly on any surface which, as a matter of fact, moves the question off the accuracy of the mesh design and on to other matters that might still be the contact points or even the FDE.
In my tests on a custom airstrip that I happened by chance to find as a candidate, I see that only the Extreme versions of Flight Replicas' Super Cub are able to overcome the bumps without flipping over (though still not as smoothly as the A2A's) but all the other Cubs (Standard and Classic, sorry I don't have Ultra version, is that so different from the Extreme?) just can't.
I'm trying to make a video of the comparison because that would be worth a thousand words.

Christian

[dandog]

Here are some shots took that make me believe it is a scenery issue. After loading each plane, I cycled through all the views, after which they would sink. I am sure that many of the aircraft will look familiar. I am not trying to be a PIA (plane in the a$$), but would like to see a remedy too. Again, that had better be a good shipment of heroin to get me to try to land at I99D.

[griphos]

I see what you're talking about, but I don't think the phenomenon of "sinking" has anything to do with the problem. I can change whether the wheels seem to "sink" by changing the radius of the wheels in the contact points. But that will affect what the wheels look like on "paved" surfaces as well (it makes the appear above the ground). I've never had any issue of being stuck or flipping follow from this graphical "sinking." I have those problems many times when there is no "sinking."

I believe (of course, I don't really know) that this is a simple matter of visual harmonizing. As discussed in posts in this thread in the high teens and low 20's, it appears that sometimes the drawing of the plane skin and the ground "skin" sometimes don't line up. This is more pronounced on rough strips or off field. Sometimes, the tailwheel is above the "ground" but is actually riding as it should on the actual mesh, just not the graphical "skin" of that mesh. Sometimes, the gear "sink" into the ground, but are actually rolling just fine on the actual mesh. I suspect that in all the cases you picture above, the planes were rolling just fine and not "stuck" in any way.

So, whatever is causing the bad handling isn't in the mesh, I don't think, since planes that do sink for me, as in your pictures above, still don't have any trouble rolling on that terrain and don't get stuck or flip over as the Super Cub not infrequently did before I changed the contact points today.

[dandog]

I'm using FSGX2010 as mesh. How do I get ORBX To Co-operate.

[bstolle]

Here are the original settings in the Experimental version:

point.3=2, -1.0, 17.0, 1.90, 2000, 0, 0.000, 0.0, 0.00, 0.0, 0.000, 0.0, 0.0, 5.0, 0.0, 0.0
......
......

Here's what I put in from the C185:
......
......
point.3 = 2, -4.60, -17.0, 3.28, 1500, 0, 0.00, 0, 0, 0, 0, 0, 0, 5, 0, 0 //LW

1. The result is that it handles much, much better!
2. I can change whether the wheels seem to "sink" by changing the radius of the wheels in the contact points

1. If you really left out the first 3 contact points all the changes you made can change nothing concerning the taxiing behaviour because you only exchanged the scrape points of the wings etc.
There's not a single change the concerns the wheels so this a pure placebo effect! Using contact points from different planes is a very bad idea.
At best you could try to use the static compression, compression and damping ratio from another plane but not even that is recommended.
2. Again, this is a placebo as changing the tire radius has no effect on the visual model concerning the way she sits on the ground

Here are the numbers for the standard super cub

point.0=1, -16.0, 0.0, -0.83, 2500, 0, 0.256, 60.0, 0.06, 2.5, 0.3, 0.0, 0.0, 0.0, 0.0, 0.0
point.1=1, 0.9, -2.95, -4.55, 2500, 1, 0.70, 0.0, 0.09, 4.0, 0.2, 0.0, 0.0, 2.0, 0.0, 0.0
point.2=1, 0.9, 2.95, -4.55, 2500, 2, 0.70, 0.0, 0.09, 4.0, 0.2, 0.0, 0.0, 3.0, 0.0, 0.0

Change all the red values (damping ration) to 1.0 and let me know how that works (same goes for all Super Cub version without ruining anything)