Ground handling in 11.10 beta 8

[soaring_penguin 428]

I am surprised no one brought the subject up yet:

Quote

Steering Gear Rate Limiting

X-Plane 11.10 has an option to rate limit how fast gear that steer can turn. This is a good thing - in the real plane you just can't turn that tiller very fast, but if you have a $20 Microsoft Sidewinder from 2002 with the throttle tab broken off (for example) you can twist it to full deflection almost instantly.  When this happens, X-Plane turns the wheels instantly, and since they're not at a 70 degree angle to your movement path, they skid like Ken Block landing a Baron. Once the wheel is in skid it has pretty much no ability to turn the plane and you just skid.

With rate limiting, the wheel will turn a little bit, and be able to put out side force, helping the plane begin to rotate.  As this happens, you can turn more and gradually angularly accelerate the aircraft into a turn.

So ... rate limiting is good - you should use it!  But the compatibility code in beta 7 was pretty broken - it set the minimum rate to 1.0, which is way too slow for a bunch of aircraft.

Beta 8 fixes this - the minimum rate is 0 (meaning no limiting) and this is the default for 11.05 planes.

I found that at least the default Cessna is behaving much better now on the ground, and also the skidding noises almost completely gone now. I can take off in a straight line now with light cross winds, what I was virtually unable to do before with my trusty Saitek x52.

The ground physics were all right, as it seems, only the steering wheel was binary (full left or full right I mean).

[Murmur 3,941]

The ground handling seems improved.

The effective max crosswind for the default C172 is still around 15kts, so the excessive weathervaning is probably still there and (as I always suspected) the one to blame.

If they improve that as well, there shouldn't be any more issues during ground handling and in crosswinds.

 

[soaring_penguin 428]

11 minutes ago, Murmur said:

 

The effective max crosswind for the default C172 is still around 15kts, so the excessive weathervaning is probably still there and (as I always suspected) the one to blame.

This would be indeed the max allowed, when checking cessna fora, I found:

http://www.cessna172club.com/forum/ubbthreads.php?ubb=showflat&Number=67758

Also something I think we armchair pilots forget is to keep the wing down against the wind (I noticed this when taking a real flying lesson offered by my loving wife).

[Murmur 3,941]

12 minutes ago, jh71 said:

This would be indeed the max allowed, when checking cessna fora, I found:

http://www.cessna172club.com/forum/ubbthreads.php?ubb=showflat&Number=67758

That's the max demonstrated crosswind as indicated in the POH, but all around the web (including in the website you linked) you can read accounts of pilots taking off and landing in significantly higher crosswinds, about the double of what is possible in X-Plane.

[Janov 2,383]

 

[ryanbatc 12,775]

2 hours ago, Murmur said:

That's the max demonstrated crosswind as indicated in the POH, but all around the web (including in the website you linked) you can read accounts of pilots taking off and landing in significantly higher crosswinds, about the double of what is possible in X-Plane.

yes thanks for posting this...  people think "oh!  max crosswind is 15 kts!"  No lol...  the piper warrior I flew in was about the same but I've been in a lot stronger crosswinds!

[jcomm 5,890]

Janov,

thx for the video, and just a comment ... 

At 15 knot or even less effective x-wind, taxi, and even more takeoff, should, IMO, be performed with considerable yoke deflection "into" the wind. I observed your takeoff occurred with only rudder being employed. IRL the possibility of the upwind ( left in your example ) being lifted, even while taxiing, is considerable.

 

 

 

 

 

[sd_flyer 6,029]

8 hours ago, ryanbatcund said:

yes thanks for posting this...  people think "oh!  max crosswind is 15 kts!"  No lol...  the piper warrior I flew in was about the same but I've been in a lot stronger crosswinds!

"Demonstrated" doesn't mean absolute maximum of course. Nevertheless, I know many euphoric pilots (including CFIs) who a bit overestimated they actually abilities to handle x-wind and ended up loosing direction control. I actually lost my CFI check ride plane ( PA28R) due to newly commercial certificate reciepint took his girlfriend for a joy ride and crashed the airplane to the hangar at St George Regional (due to crossing miscalculation of course :) ). I think though, he meant to go around after realizing that he could roll straight, so he hit hangar with a lot of loud sounds. 

The crash smashed Arrow wing spar, engine mount and empennage resulting  beyond repair state. On the positive note, pilot and passengers walked out from the crash without scratch. However, I ended up finishing my CFI in Mooney which put big dent in my self estimate due to many failed attempt of power of 180 in M20J LOL

 

 

[ryanbatc 12,775]

Well, as for the sim, it looks like they model things based on book numbers.  I've found the same too for VOR's and service volumes in XP...  low altitude vor's are exactly 40 miles.   Or they used to be.  In real life of course they can be much better.

Glad everyone was ok.  Amazing they walked out!

[Janov 2,383]

9 hours ago, jcomm said:

Janov,

thx for the video, and just a comment ... 

At 15 knot or even less effective x-wind, taxi, and even more takeoff, should, IMO, be performed with considerable yoke deflection "into" the wind. I observed your takeoff occurred with only rudder being employed. IRL the possibility of the upwind ( left in your example ) being lifted, even while taxiing, is considerable.

 

 

 

 

 

 

Hi Jose,

you are absolutely right, of course - I did not deflect the yoke (and add a bit of pressure on the nosewheel, too) to show that it is not necessary to maintain directional control. But you SHOULD definitely do so.

Thanks for the correction, Jan

 

[soaring_penguin 428]

The plane turning into the wind is reality. If it is overdone, or not, I do not have enough experience or the numbers to discuss this matter. But in real live, 15 knots is not negligible (approximately 30km/h). 

On the site I showed, some pilots said they did it, more said they wouldn't try it unless obliged. I expect it is not pleasant in real life, so even less in the sim, where we only have visual feedback (no pulling on the stick, no resistance from the pedals, no seat of the pants flying).

The only thing I did notice in the sim, that at least with the default Cessna, it is much easier to follow the center line with some light cross wind component (up to 11 knots or so). Before, I would be all over the place by the time I got airborne, due to over corrections (as Ben explained, it used to be all or nothing, without interpolation between frames). This is with a twitch joystick, I really must try it with my pedals next.

Probably I will need to go into Planemaker to adjust this rate limiter for third party planes ?

[jcomm 5,890]

1 hour ago, jh71 said:

 

Probably I will need to go into Planemaker to adjust this rate limiter for third party planes ?

I've seen this mentioned in another thread? Is this setting a new feature in the latest betas ?  Where can I find it and, what exactly is it supposed to do ?

[Janov 2,383]

There was some confusing and involuntary revision with the Laminar default airplanes in the beta 7 and beta 8 run. Laminar fixed a problem that set the rate on ALL aircraft to 1.0 seconds deflection (from center to full deflection) - but unfortunately the aircraft files somehow got corrupted, so now the aircraft (at least the C172 and B58 I checked) have their deflection times set to 1.0s.

This will be corrected with the next update. You can fix it in planemaker yourself, I think the relevant tab was control geometry or so. You will know when you see it.

Cheers, Jan

 

[jcomm 5,890]

9 minutes ago, Janov said:

There was some confusing and involuntary revision with the Laminar default airplanes in the beta 7 and beta 8 run. Laminar fixed a problem that set the rate on ALL aircraft to 1.0 seconds deflection (from center to full deflection) - but unfortunately the aircraft files somehow got corrupted, so now the aircraft (at least the C172 and B58 I checked) have their deflection times set to 1.0s.

This will be corrected with the next update. You can fix it in planemaker yourself, I think the relevant tab was control geometry or so. You will know when you see it.

Cheers, Jan

 

Ah!  Ok, I see Jan. Thx!

[sd_flyer 6,029]

Sorry for offtop. One of SoCal local airports on the windy day