http://forums.x-plane.org/index.php?s=36f5bbad7bb9ee3fc5bb2a4bd78f80c1&showtopic=69706#entry757221

 

Mentioned in the Centurion thread....

Now I'm really curious to see what developers will (and what they can) do with this finding. If it puts an end to the everlasting roll-debate, that would not only make X-Plane better, but very likely that forum here, too

Thanks jcomm!

The acknowledgement goes to Pinky who gave us the link to that thread at the .ORG, on the other Centurion thread...

 

Curious is that I have been debating this with many, including Brett, and I am sure it's a recent finding. Probably a recent dataref too (?)

 

And just now that I was getting acostumed to call him Austin (torky) Meyer :-/

I'll have to change that again to Austin (mighty) Meyer :-)

Now, I might not be able to test the actual amount of compression for the left gear structure, of a plane I might design. And will P-51's not roll on their back now.....if they ever did?

 

Actually, the changes made are fine with me. I wouldn't use X-Plane to test climbs in blind mountain canyons, or be testing takeoff distances with high density altitude conditions.....either. At least as far as making real world descisions go.

I'll try to test it.

 

With access to this dataref everything can be done. We can even make it depend on AoA ( just like in RL ), etc... I could even try my "dynamic pressure algorithm" :-)

 

It's a very bright light at the end of the tunnel for me and I'm going to follow it....  After all, that's what I've been asking for quite a long time ;-)

 

I'll try to post here my findings anyway ...

 

Larry, using the demo you can test it to. Simply move that plugins and lua script into your x-plane folder as explained at that thread in the .org...

Larry, using the demo you can test it to. Simply move that plugins and lua script into your x-plane folder as explained at that thread in the .org...

At this moment, I haven't even bothered to hook the sound back up to my computer since I moved. Let alone flight controls. It's going to have to be an all the bells & whistles machine, before I do anything. Hopefully soon!

I lifted this from X-Plane org this evening..

Same thread as linked in this thread.

 

Actually, the torque setting we've been working with thus far is "1.0", in other words, X-Plane's default. Our planes are calibrated to consider this the realistic value, although many people, especially those coming from FSX, find this hard to get used to, or downright disagree with the way X-plane models this.

 

"This whole thing may be opening up a whole can of worms, and is more intended as a guideline for people who want to tweak something to their OWN liking.

 

What I'm stating is, that I won't be going back and publishing tweaks or recommendations for the past planes that have been released so far. This is merely a way for end-users to make tweaks, if they so desire.

 

This isn't really an FSX thing, and what we are use to. We didn't complain in FSX, because most of the time, the problem didn't exist. I complain because I fly real airplanes and it doesn't exist! If you're to search the vast internet for pilot reports of every airplane I checked out, and more, which includes turboprop twins, high powered WWII fighters, etc, and etc...........I doubt you'll find a single reference, in which the pilot is fighting an induced torque roll on your climbout & cruise. I didn't find any! Lot's of mentioning torque with one engine out on twins, or on the takeoff roll. I watched many video's that included moving the yokes one direction or the other after takeoff. It's a crosswind correction, rather than harnessing torque roll. Engine induced torque roll would be dangerous as a normal part of every takeoff. It's wiped out many pilots and aircraft during high power, low airspeed events, such as go-arounds in WWII airplanes. Austin Meyer even made it a point to discuss the elimination of any "heavy" wing roll, with his new Lancair (high powered) turboprop kit plane. I'm into kit planes too, and as (experimental aircraft) test pilots, thats what we do. Heavy wing, applies to either wing. It's either a rigging, or fuel/passenger weight scenario.

 

I'm interested in farther responses to the thread above. Some now think that roll is a true part of piloting an airplane. I read many sim forums, in which it's assumed to be accurate. I've seen a lot of replys to those that ask about the roll.....being told "to learn to use trim". And then of course, there are those who say it's just my opinion. It's best to read up on the subject, if you doubt.

So what exactly would you like to see done at this point, ideally speaking?

So what exactly would you like to see done at this point, ideally speaking?

I'd certainly make the file fix as suggested.

 

If someone finds trimming the roll as being more challenging, and something extra to do, to add a little more excitment to the sim, than leave it alone. I'd see it as a real life stability problem.

 

P.S. -- to my above reply, I should have mentioned yaw. Lots of pilot flight reports about yaw & the rudder pedal.

 

A big edit:

 

Going back to the org., it appears your the one making the changes. GREAT!!! Then eliminate the roll! I suppose it would effect any sensation of a left wheel pressing against the runway, but it's a lot better having a phoney sensation in the climb & cruise. It's been an irratation for me, for a long time. Searching the interenet, in regards to flight sims, you'll see quite a few pilot complaints. Especially for some specific twin turbo props. Then somehow, the threads just stop. This topic is something I bring up nearly every week, at Sunday breakfast. Just a bunch of pilots & spouses, who actually don't use desktop sims.

 

Somewhere, I read about using an X-Plane Cirrus SR22. I don't know the XP model used. The sim pilot talked about wrestling the rudder for yaw, on the takeoff roll, and then wrestling the yoke & aileron trim on the climb. As to myself, I checked the actual Cirrus SR22 for engine cant, which it had, and then talked to two different instructors who flew the plane. The "roll" doesn't exist for the Cirrus, but the simmer assumed it does, because of a larger engine. And since you're new to this forum, I also discussed this phenomenon with my hangar partner who is a commercial pilot, and owns a Pitts M-12 with a Russian radial (approx 400 HP) and three blade prop. This plane can easily do torque rolls on the vertical, but it doesn't want to drop a wing at rotation. My own RV6 would press the left wheel down like crazy, if you hit the throttle on a touch & go, but it the torque was overcome by lift & engine cant, by the time I rotated. Rotate too early, and there can be some wing wobble. But there is no sensation of a swing to the left in the stick, or at least enough to even think about. As a crop duster told me......the roll from torque is inconsequental on the climbout. And his plane was packing arounf 2000 HP.

 

 

And then of course, there are those who say it's just my opinion. It's best to read up on the subject, if you doubt.

 

Well, a quick Google search for "torque effects propeller" seems to indicate that this is a fairly well-documented phenomenon, in accordance with the laws of physics.  Now, if it may be OVERDONE in X-Plane is a different question, one open to interpretation.

 

Well, a quick Google search for "torque effects propeller" seems to indicate that this is a fairly well-documented phenomenon, in accordance with the laws of physics. Now, if it may be OVERDONE in X-Plane is a different question, one open to interpretation.

Of course it's a law of physics. There is a lot written about it. Now go farther, and see what real effects it has in the scheme of things. It is overdone. Sometimes terribly! As far as I'm concerned, I won't even say it's open to interpretation. As I edited my previous post, I mentioned an ag pilot, who dusts crops with a turbo powered Air Tractor. This subject came up on one of our experimental builders forums, in which he responded. At first he said, there certainly IS torque, and also mentioned the P-51 Mustang, as well as a few other WWII fighters. He said, yes, you control the roll with aileron. A week later, he comes back, and says, in all reality, there just isn't enough engine induced torque to think about. It was inconsequental during the climbout. In other words, he made it a point to notice, during his flying session. You'll find many pilot reports, including WWII birds, that say the same.

 

In the end.....the torque is overcome by the wings lift & engine offset. That beats any old concept of designing wings with different incidences, or relying on trim tabs, which introduce an opposite roll, when power is reduced, such as a descent. My RV6 had perfect alignment of the wings. I referred to it, as a torque monster on the roll, with plenty of right rudder. But then I have plenty of climb photos with the ailerons perfectly aligned to the flaps and wing tips.

Well,

 

I have successfuly edited a few aircraft this morning, and all I can say is that this fix is indeed very effective, and doesn't make any harm to other flight characteristics, or at least doesn't have the consequences of using irrealistic trim tab settings for airlerons, engine cants that are not used on some airplanes in RL, asymmetric wing camber, etc...

 

Another positive outcome of this fix is the fact that prop effects now map more efficiently to yaw and thus it is possible to make correct se of rudder to counter under high power / AoA flkight situations :-)  Of course for it to be even more perfect, don't forget to clear the irrealistic trim tab settings used before to overcome the excessive roll due to torque. I am not saying hat you should make the torque scalar = 0.00, thus a of aileron trim tab should be set, as in RL, but that's about it. The same goes for rudder trim tab / tail fin cant...

 

My only problem now is editing multi-prop aircraft. I haven't figured yet what's the right way to do it... For instance I tried this in the default C90:

 

defineProperty("torque", globalPropertyf("sim/aircraft/prop/acf_prop_dir[0]"))  set(torque, 0.30)

defineProperty("torque", globalPropertyf("sim/aircraft/prop/acf_prop_dir[1]"))  set(torque, 0.30)

 

but it doesn't work :-/

 

Using a single entry doesn't produce any effects either.

 

I posted at the .ORG forum asking for advice from Dan, and expressing to him, and Brett, my gratitude for having made these available to the user community.

 

Each one should now decide how to tweak his aircraft, always making a backup of previous versions.

 

I have edieted most default and add-on aircraft to adjust things like CoG placement, sometimes responsible for weird 6DOF rotation paralaxes when the aircraft are seen from outside views... I have also adjusted the radii of gyration, usualy to get them back to the default values calculated by X-Plane 10 itself which are very good, etc... This "TorqueFix" is just another tweak, and it made quite a difference on aircraft I really am enjoying to fly, such as the DR-400 from XPFR, Austin's Lancair Evolution, etc...

 

 

EDIT: Dan Klaue has just kindly replied:

 

http://forums.x-plane.org/index.php?showtopic=69706&page=2#entry757374

Ok, so here go my tweaks for the default C90 in XP10.22:

 

In Plane-Maker, Standard / Control Geometry / Trim & Speed:

 

 

 

and I edited "avionics.lua" in the root folder of the aircraft and placed there only the two following lines:

 

defineProperty("torqueL", globalPropertyf("sim/aircraft/prop/acf_prop_dir[0]"))  set(torqueL, 0.25)
defineProperty("torqueR", globalPropertyf("sim/aircraft/prop/acf_prop_dir[1]"))  set(torqueR, 0.25)

 

No more need for fancy / irrealistic trim tab settings, or artificial stability :-))))

Ok, so here go my tweaks for the default C90 in XP10.22:

 

In Plane-Maker, Standard / Control Geometry / Trim & Speed:

 

X-System_1.png

 

and I edited "avionics.lua" in the root folder of the aircraft and placed there only the two following lines:

 

defineProperty("torqueL", globalPropertyf("sim/aircraft/prop/acf_prop_dir[0]"))  set(torqueL, 0.25)

defineProperty("torqueR", globalPropertyf("sim/aircraft/prop/acf_prop_dir[1]"))  set(torqueR, 0.25)

 

No more need for fancy / irrealistic trim tab settings, or artificial stability :-))))

Thanks for this jcomm.  I am flying more and more in Xplane and will try this.  By the way, all the tweaks you mentioned (e.g CoG etc.), did you do them for Carenado models?  If so could you PM me with them please?  I like XPX feel of flight much better, for example the F33A feels better in XPX than the one in FSX but I am not a RL pilot and most of my RL flight was in the left seat, so I can't tweak the models using PlaneMaker like you do.

 

Thank in advance.