FR Super Cub problem taxiing on bush strips

[griphos]

Well, I bought the FR Super Cub Extreme package a while back and have been flying it a bit. I was wanting a good bush plane with a little more speed than the A2A Cub, and a little more oomph for higher altitude strips.

So far, I like how the plane flies, but I've been flying it at regular airports for the most part. The past couple of days, though, I've flown it to bush strips along the Salmon river country. These are the kind of strips the Super Cub was made for, I would think. She lands fine at these strips, but when I try to taxi her to turn her around or back taxi to the end of the strip, all hell breaks loose. It's as if her tundra tires have sunk into the ground. I have to apply almost full throttle. The tailwheel lifts but she doesn't go anywhere. And no, I don't have my brakes on. When I do get her moving, it's impossible to keep her on her gear. I hold full back stick, and move at slow speed, but she'll plant her nose or start doing worse gymnastics. It's very frustrating.

These are backcountry strips, with rough terrain, but then that's what this bird was designed for, and I fly a lot of other aircraft just fine at these strips, the A2A Cub, and the Birddog, and the Scout, and the C185. Shoot, I've flown the RV-7 at these fine. I don't have any problem with any of those.

Is this a general experience with this aircraft? Does anyone know how to alter the aircraft.cfg to tame her ground behavior? As it is, these planes are unusable at the precise airstrips I bought them for and that they are designed in RL to fly at. Any help appreciated.

 

[napamule]

UpDate?

There was a MODEL update for this A/C. But if you bought it after August 14, 2011 you already have the latest files (FDE too?). After that you need to get some tips.

Like using rudder pedals with auto-coordination OFF. Or a good joy stick with sensitivities set to 100% with 0% null. Then you reduce your fuel load. Then you learn to TRIM so level flight is possible at slow speeds (stall +5). Of course throttle (power) management is also vital. You should have a way to give or take throttle QUICKLY. Then you practice touch down just as stall warning goes off. After a few weeks (months) you can fly without looking at panel and going just by sound of engine.

For finding a strip I map a joy stick (thumb) button to toggle 'top down view' and then I zoom in with '+' key. Nothing like it. Good luck.
Chuck B
Napamule

 

[griphos]

Thanks for the response, but you didn't read my post carefully. I have the latest version, and I don't need flying tips. I fly it fine, and land it fine. I'm a RL pilot and own a similar airplane. I have my sensitivities set correctly on controls and have pedals, etc.

There is no problem flying or landing this model. The problem is with TAXIING on backcountry bush strips. The cfg is set to respond to the uneven terrain in a way that makes it impossible. I have well over a thousand sim hours with a LOT of payware and freeware aircraft, many of them in just these kinds of strips, and have never had this problem. As long as I am on the middle of the strip, I'm okay, but when turning around or taxiing to the side of the strip, and rolling over the terrain, which is still flat enough and causes no problem for any other airplane, the FR Super Cub goes crazy, flipping and crashing.

Anyone else fly this airplane into these kind of strips and know how to modify the cfg so that the plane stays on its gear?

 

[bstolle]

Do you have acceleration installed? If not that would explain your problems.

 

[griphos]

Yes, I do. I have FSX Gold installed, and have the F-18, etc. I saw the notice on needing Acceleration before buying. But it doesn't say what problems occur without it. I thought I remembered from some threads in the past that it causes bouncing on landing. Is that right? I have no problems landing. It's taxiing that goes crazy for me, and only off the strip. I can taxi okay as long as I stay right on the strip itself, it appears. But then I can't really turn tight enough to stay right on the strip at these very narrow backcountry strips. As I've said, I taxi off the strip in these same airstrips just fine with all my other planes.

I'm happy you've responded though, since I know you worked on the FDE for these. Not sure you did anything with respect to the ground handling parameters. Have you noticed this behavior, if you've flown these planes at these kinds of backcountry strips?

I'm going to do some more experimenting with some larger airports and taxiing off the taxiways and runways and see what happens. But I've tried over a dozen backcountry strips along the Salmon River with this plane and had the problem at every one of them. Landed fine, rolled out fine, but got stuck or started flipping as I tried to taxi back into position at the end of the strip if I got even a little off the "runway."

 

[bstolle]

I'll re-install the Super Cub when I'm back home in a few days and check what's the problem.
I did test the FDEs off airport of course as well.
Sure you have the updated FDEs? because I didn't make the original FDEs that intitially came with the Super Cub.
Realism sliders are fully to the right I guess....

 

[Overshoe]

I'm going to do some more experimenting with some larger airports and taxiing off the taxiways and runways and see what happens. But I've tried over a dozen backcountry strips along the Salmon River with this plane and had the problem at every one of them. Landed fine, rolled out fine, but got stuck or started flipping as I tried to taxi back into position at the end of the strip if I got even a little off the "runway."

I just loaded up the Super Cub Extreme and the Ultra and had none of those issues at several soft airfields including 2 around Stanley, ID. I was able to taxi off the runway and across the runway and into adjacent fields with no problems. Do you have some specific fields I can try? And do you have any add-on scenery installed?

 

[griphos]

I bought it about a month ago, so it should be the latest version, right? Yeah, realism full to the right.

I fly in Orbx scenery.

I just tried it at several other airfields, Bowerman (KHQM) and Clam Harbor on Orcas Island, and it did fine there off airport. So I went back to the Salmon River country. I flew off from U60, and had the same problems when taxiing on the surrounding terrain up near the south end of the airstrip. I flew over to I99D, Dewey Moore, I97D, Mile-Hi, and I08, Cabin Creek. It was terrible at Dewey Moore. I landed, and when I tried to taxi up to the end of the strip to turn around to take off, I got stuck. It's as if my wheels sank into the ground. I was still on the strip, as far as I could tell, there's not much that delineates it there, but I was approaching the little tent and campfire in the Orbx scenery, on a slight uphill incline, and I could give it full power and full back stick and all it would do was raise my tail off the ground, but there was no forward motion. I had to let it coast back.

I had similar problems at the other two. Now, these are extremely rough backcountry strips, I know. But I land other planes there and taxi without problems. The people I flew with last night in MP into these same strips had no problems. And these are the kind of strips this Super Cub is made to fly into.

Is it possible that whatever settings were made to model the tundra tires are causing this behavior?

 

[griphos]

Okay, I did some more testing. I took a few of my other planes to these strips I listed above to try them again. It's been a while since I've flown these strips in something else. I never had any problems there that I can recall, but I tried the A2A Cub and the Real Air Scout and the Carenado C185. Both the Cub and the Scout had problems moving forward at times on several of the strips, like Dewey Moore and Cabin Creek. The C185 was fine, but then it has a lot of power. But none of the other planes displayed the tendency to start flipping when off the runway, except for the Scout, at Dewey Moore, after I slewed it a bit to get it out of being stuck. And it just started a strange tailwheel bounce that I couldn't stop.

So, I'm less concerned with the "getting stuck" bit of my experience. That may just be terrain incline and low power, although when looking from the external view, the wheels on the Super Cub seem to "sink" into the terrain a lot. It may also be the way those strips are modeled by Orbx. They may be softer or rougher than most.

I also tried 2U7 and 13ID, which may have been the two strips near Stanley mentioned above. I was okay at both, although the Super Cub was still more sensitive on those strips than my other planes.

Thanks for the help so far trying to figure out what is happening. I still think the response to terrain needs to be tamed a bit. The Cub with tundras should handle rough terrain better than other planes, not worse, I would think. As I've said, I bought the Super Cub to handle strips none of my other planes can.

I'm away from home for the next couple of days and so won't be able to do any more testing for a few days.

 

[Overshoe]

Is it possible that whatever settings were made to model the tundra tires are causing this behavior?

It would appear to be a combination of causes after several tests at Dewey Moore. The combination of the "tundra bounce" and the non-standard Orbx sloped runways are a recipe for disaster. The scenery is definitely a factor since there is no problem (that I have seen) at normal flattened airports. It looks like a contact point issue to me, but I'll leave it to the experts to fix. Perhaps Bernt will have an easy fix when he gets home.

 

[bstolle]

1. when looking from the external view, the wheels on the Super Cub seem to "sink" into the terrain a lot.
2. It may also be the way those strips are modeled by Orbx. They may be softer or rougher than most.
3. I still think the response to terrain needs to be tamed a bit.
4. The Cub with tundras should handle rough terrain better than other planes, not worse,

1. But that has no influence on drag etc. (in FSX)
2. AFAIK some of their airfields need an extremely fine mesh resolution, so if the mesh is set to e.g. 1m it might cause such problems as well.
3. That's an easy one. Just open the cfg file and alter this one in the contact points section:
point.0 = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
The red one controls the springiness of the gear. point 0 is the tailwheel, 1+2 the mainwheels.
(0 = undampened 1 = critically dampened)
4. Not necessarily. If you look at the various videos at youtube etc. you will see that the Tundra tires are nice for soft terrain, gravel etc. but as e.g. neither the Super Cub or the 185 have real shock absorbers, these tires induce 'jumping' much more than conventional tires if the tearrain is bumpy.

 

[robmw]

Hi,

I've flown the Super Cub Extreme extensively in the same Orbx scenery and although not as severe, I have noticed similar behaviour on rough terrain at times. I ended up doing the edits Bernt suggested to tone things down a bit which helped.

The reason I mention this is that when testing the FR Super Cub Ultra earlier this year and subsequently I've noticed that rough field behaviour is easier to control, as is landing since bouncing appears to be damped down more than with the Extreme. I'm no real world pilot but my observation of spending a lot of time with both aircraft is that the Ultra is easier for me to control. I've managed to land and manoeuvre the Ultra in places I had very limited success in with the Extreme. Maybe my skills have improved but my guess is the flight model! I realise these are different aircraft but at the same time they must have many similarities so maybe a comparison of the two is worthwhile?

Rob W

 

[griphos]

That sounds promising. Is it possible to put the Ultra ground/gear settings in the Extreme .cfg?

3. That's an easy one. Just open the cfg file and alter this one in the contact points section:
point.0 = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
The red one controls the springiness of the gear. point 0 is the tailwheel, 1+2 the mainwheels.
(0 = undampened 1 = critically dampened)

Okay, what settings would you suggest I alter tailwheel and main gear to?

 

[bstolle]

1. Is it possible to put the Ultra ground/gear settings in the Extreme .cfg?

chances that this works are approx 99%.

 

[griphos]

3. That's an easy one. Just open the cfg file and alter this one in the contact points section:
point.0 = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
The red one controls the springiness of the gear. point 0 is the tailwheel, 1+2 the mainwheels.
(0 = undampened 1 = critically dampened)

What do settings 9, 11, and 12 control? I believe these settings are different in the Ultra .cfg also.

 

[bstolle]

What do settings 9, 11, and 12 control? I believe these settings are different in the Ultra .cfg also.

Just above the [contact points] section, there's a full explanation.

//0 Class
//1 Longitudinal Position (feet)
//2 Lateral Position (feet)
//3 Vertical Position (feet)
//4 Impact Damage Threshold (Feet Per Minute)
//5 Brake Map (0=None, 1=Left, 2=Right)
//6 Wheel Radius (feet)
//7 Steer Angle (degrees)
//8 Static Compression (feet) (0 if rigid)
//9 Max/Static Compression Ratio
//10 Damping Ratio (0=Undamped, 1=Critically Damped)
//11 Extension Time (seconds)
//12 Retraction Time (seconds)
//13 Sound Type

 

[griphos]

Thanks. I missed that. Okay, I'll experiment with these a bit, using the Ultra settings as a starting point. A few more questions, though:

What would the difference in //9 Max/Static Compression Ratio do between, say, a setting of 2.5 and a setting of 4.0?

I notice the //8 Static compression in feet is typically .06 or .07 for both the Extreme and Ultra on the tailwheel, but about double on the main gear (0.09 for the Extreme and 0.2 for the Ultra). Would you recommend the higher setting?

I also notice that the wheel radius settings for the Extreme are less than 9" (setting of 0.70). This isn't correct, is it? All of these aircraft have extreme tundra tires on them of at least 32" radius, right? Could this be having an effect on handling?

I notice the steering angle of the Extreme tailwheel is 60 degrees, but the Ultra has 180 degrees, making it free castoring, basically. Isn't the tailwheel of the Extreme Cubs free castoring as well? If I change this to 180 on the Extreme, will it allow it to turn tighter circles on the ground? It needs to. One of the reasons I wind up off the runway so far while taxiing, is that it is very hard to turn the Extreme Cub around.

I notice the Ultra has Extension times of .1 second but the Extreme has no extension times (0.0). Does this make much of a difference? Is this gear extension and retraction times? If so, neither of them has retractable gear, so the setting shouldn't make any difference, right?

 

[bstolle]

1. I also notice that the wheel radius settings for the Extreme are less than 9" (setting of 0.70). This isn't correct, is it? All of these aircraft have extreme tundra tires on them of at least 32" radius, right? Could this be having an effect on handling?
2. I notice the steering angle of the Extreme tailwheel is 60 degrees, but the Ultra has 180 degrees, making it free castoring, basically. Isn't the tailwheel of the Extreme Cubs free castoring as well? If I change this to 180 on the Extreme, will it allow it to turn tighter circles on the ground? It needs to. One of the reasons I wind up off the runway so far while taxiing, is that it is very hard to turn the Extreme Cub around.
3. I notice the Ultra has Extension times of .1 second but the Extreme has no extension times (0.0). Does this make much of a difference?

1. That wheel size is incorrect (leftover from the standard PA18 I'd say) but it has no effect on handling.
2. The Super Cub has a 'special' steering which can't be duplicated in FSX, so it's your choice what you prefer or what's easier for you. Taxiing with a free castoring tailwheel is much more difficult but it's easier to turn on the spot.
3. You can disregard these numbers.

Again, I suggest adjust only the damping ratio to your liking (and the tailwheel steering) as most other values interact with each other!

 

[griphos]

Thanks again for the help. I changed the tailwheel angle to 180 but that seemed to make it harder to turn. Go figure! I put it back to 60 but may try 80 or 90 just to see.

I changed the wheel size to correct, and although it may not affect handling, the wheels now sit on top of the ground in external view.

I changed the dampening, but also the compression settings to match the Ultra. There is a definite improvement as a result. I only got the flipping once on testing again at these strips, and that was after slewing to a flatter, but apparently still rough spot, after getting stuck again.

She's still more sensitive than I think she should be, certainly more than my other planes, and still has a tendency to dive on her nose even with full back stick, but she's at least flyable into these strips now.

 

[bstolle]

1. I changed the tailwheel angle to 180 but that seemed to make it harder to turn. Go figure!
2. I changed the wheel size to correct, and although it may not affect handling, the wheels now sit on top of the ground in external view.
3. She's still more sensitive than I think she should be, certainly more than my other planes, and still has a tendency to dive on her nose even with full back stick, but she's at least flyable into these strips now.

1. That's what I said. More difficult to taxi as there's no connection between the rudder and the tailwheel. For really tight turns you need a burst of power, apply full rudder and differential braking.
2. That' really weird. Tried and didn't notice any difference in appearance (not even by increasing the size by 1ft)
3. The Super Cub has a trimmable stabilizer! Without re-trimming you run into serious controllability problems even with full back stick. That's one of the reasons I've deleted all of my Super Cubs except for the standard one. She's easily the most beautiful and nicest handling of all the available variants.