I really think it's a lost cause. I did make the adjustments Tom suggested and the throws were reduced but the Baron still rolls back and forth. When I fly my rc stuff for the most part the ailerons are neutral when I take off. If they need adjusting I can deal with it when airborne. Is that not the way real aircraft behave?

 

If I take off in the default Baron with ailerons neutral, as soon as it's off the ground it wants to roll hard to the left, why is that, torque roll, way too much if it is? I couldn't fly my rc planes if they behaved like that. It would take about 2-3 seconds to flip the Baron over if I wasn't hard on the yoke. So I give a few clicks right aileron and it comes to center and keeps going right. Give one click left aileron and it wants to go left, get the picture? It does not "seem" realistic at all, again I'm not a real pilot but I do fly planes with 5' wing spans and they don't fly like this, constant rolling back and forth that you can't stop with a bit of trim.

 

Goran, if you read this I just tested with the Duchess and at least I could get it trimmed and sit back for 30-45 seconds without it starting to move, or wanting to roll over. It would eventually start to move but it felt more like what I imagine flight to be. I wasn't constantly on the yoke or trim buttons. I did these tests with zero weather.

 

I read everything.

(What better way to stay on top of peoples wants and needs than to read the various forums).

:wink:

Muskoko, my opinion on the matter is more related to what we believe or interpret as happening vs what is really happening...mostly because simming is just too limited in front of a computer compared to reality. The most famous case for this (at least to me) is my MU2 add-on. It has massive torque roll on takeoff...the engines putting out nearly 2000 horsepower on the takeoff climb at sea level. Folks just didn't believe it was real....folks with no time in an MU2. I have about 40 hours in one myself and my good buddy has 4000 and when I asked him about whether or not it rolled, his answer was...."I don't know...never bothered to think about it". He just flew the plane. One thing has been a constant in those MU2 hours I've flown and the 172 hours I've flown..and that is when the plane is in trim, you STILL have to fly it. If you take your hand off, the plane will drift in some direction..it will roll, climb, descend something.

 

In reality, you just "put pressure" as the instructor likes to say.....to fly the plane...gentle pressure, but pressure none-the less. You need the slight pressure cause if you didn't, the plane wouldn't fly straight and level. Ever see a pilot in a video (or reality) manually flying a plane with this hands off the controls? For you car drivers..you can take your hands off the wheel....for a little bit, but inevitably, the car will drift...same with an airplane. straight and level hands off just doesn't exist. I can't say I've known anyone to trim an airplane and then just stare out the window for more than maybe 20s before they have to grab the yoke again to correct movement.

 

Now as far as the amount of roll....twins with engines spinning the same direction do require counter input of some level. I present a video I have presented many times when addressig the MU2 roll. The takeoff starts at about 3:00 in and you'll note that the pilot holds the yoke to the left for the most part. I say for the most part because you will alway note he's always moving the controls. Flying is just busy business and I think x-plane is pretty good about it in that regard....I just think the the computer and hardwars limited resolution can't give you the very subtle pressure inputs you get in reality and this perception is what's off. Now I can argue that if the perception is off, then the simulation is off for you and we can indeed ask what can we do to make it better for you vs what can we do to "fix it"...as others may not think it's broken. That's a question I'm willing to engage in any day.

 

As far as zeroing the trim on the baron, usually it's the number 9 on the keyboard. But the baron will roll on takeoff as in the video below and you have to counter it until you get the roll trim right..and even then you can expect to have to stay on top of the flight.

 

As far as comparing it to RCs...Im not a big RC guy, but have done it in years past and I can't remember doing many straight and level runs that didn't last more than bout 10 seconds for a slow plane and unless you have a camera on the plane, you don't really know how much its rolling.....and keeping a real plane in trim for 5-10 secs is very doable so they MIGHT be similar, just not perceived as similar since you are in a much more analytical mental state in front of XP rather than at the controls of your RC. I think if pilots took an analytical look at how much the fiddle with the controls, even in trim, they just might surprise themelves. Thats my opinion anyhow.

 

TomK

Laminar / IXEG

 

same with an airplane. straight and level hands off just doesn't exist. I can't say I've known anyone to trim an airplane and then just stare out the window for more than maybe 20s before they have to grab the yoke again to correct movement.

 

LAdamson can...in his Vans RV6...in the mountains.

My friends Piper Arrow (and most pipers) are so stable that when I first met him he bragged he didn't need altitude hold on his autopilot. He was right- even on rough days once trimmed it never, ever got more than 50 -at most 100 ft. off when it would slowly correct itself back to the desired altitude.

 

A baron or bonanza-in very, very calm air for a short while-but anything else and you can not fly it hands off more than a few seconds.

 

The Carenado aircraft have the correct responses I can relate to from their real world counterparts with no adjustment on anything and were the sole reason I am still using xplane. They still exhibit the over torquing though and will roll immediately to the right quite rapidly after trimming for level flight which is not correct.

Well as I stated I'm not a pilot, but if a real Baron flies like the one in XPX, I would never buy one or want to fly it for that matter. I find it hard to believe they fly like that in the real world.

They don't....

LAdamson can...in his Vans RV6...in the mountains.

 

I don't fly with the hand off the stick, unless it's on auto-pilot. The RV actually has a two-axis A/P that will fly a GPS route. However..........I'm NOT constantly adjusting for "torque roll". It just doesn't exist after takeoff. If I was to immediately go full throttle on a go-around or touch & go, the torque roll to the left is quite pronounced in the RV6. It really got me surprised on the first touch & go, since it was so much more than a Piper or Cessna. It litterly pushed down on the left gear leg.

 

Nope.................this constant rolling in XP is incorrect..............period!

 

L.Adamson

One thing has been a constant in those MU2 hours I've flown and the 172 hours I've flown..and that is when the plane is in trim, you STILL have to fly it. If you take your hand off, the plane will drift in some direction..it will roll, climb, descend something.

 

As far as I'm concerned, unless the aircraft is totally on a two-axis A/P as minimum, then it won't be maintaining the same heading or altitude for long. Yet, you still won't be feeling a force of roll, that requires constant aileron adjustments. Moving the stick/yoke fore & aft or left & right, is just to compensate for air currents, that tend to move the airplane from a straight & level trajectory. If it's calm air, then the movement is very small.

 

This is quite different from the sensation of a "heavy wing", that requires a fair amount of aileron trim to compensate. There are numerous ways, in which a heavy wing is adjusted in full size or R/C aircraft. The idea, is to not have it during normal cruise flight.

 

L.Adamson

They don't

 

The torque exists Geofa and its reaction, so the question I want to ask you is how do you believe it is compensated for such that a Baron doesn't roll with neutral trim as you assert. I'm not saying that it does or doesn't, you clearly have more Baron time than I, but I am saying that if is doesn't, it's because something is balancing the torque reaction from the engines and I'd like to know what it is cause if I do, I can tweak XP to match Trim tabs are a reality for real aircraft but nobody messes with them in x-plane flight modeling and this could be the key to refining the model to be more accurate....Looking at some net pictures, it looks like there's a tab hanging off the training edge of the right wing...what is your take on that?

 

TK

I love these challenges! Here is a video of the Baron in straight and level flight - default Baron, no plane-maker tweaks.

 

Please not that I did adjust the trimsetting with the trim-wheel controls in the 3D cockpit - the joystick buttons (or even the keyboard) will only get you so close.

 

 

http://youtu.be/ZBY85cbdwSI

 

I find the Baron to be fairly stable around all axis, if you put in a 10 degree bank when trimmed like this it will right itself without further input.

 

There are other default aircraft that are not as stable, unfortunately.

 

The correct technique for trimming is like this: Level wings and stop the yawing tendency with rudder trim. Now use aileron trim to make the plane keep wings-level.

 

After that you can experiment with the new "neutral" bank of the plane - usually it will settle steady at a few degrees left or right. Now use tiny inputs of the trim wheel in the cockpit to adjust.

 

Jan

it's because something is balancing the torque reaction from the engines and I'd like to know what it is cause if I do, I can tweak XP to match

 

tkyler, unfortunately I strongly believe that's a task for Austin to deal with... just as with the tunning of turbulence...

 

When he introduced the torque effects by xp9, just as we feel them now, he probably forgot to include additional prop slipstream calculations to account for the asymmetric hit of different aircraft surfaces, tending to:

 

1) Compensate for the torque roll moment;

2) Causing more of a yaw than a roll moment, unless we're talking really powerful ww2-type or aerobatic aircraft...where then you really have to add also the magnitude of yet another type of effect - gyroscopic!!!

 

Regarding 1), there are other threads where I exchanged some oppinions with Murmur about this, but the basic idea is that if you try to visualize the corkscreewing slipstream that flows along the airplane, you will "see" that part of that flow (assuming a CW rotating prop) hits the left wing from bellow(and or the righ wing from the top), thus creating a right rolling moment and countering the roll moment created by the rotating prop/engine. Now the same can happen with the horizontal stab, while the vertical stab, being hit from the left, will create a left yawing moment, and that's why on typical GA aircraft the ball moves a lot more to the right on takeoff and steep high power climbs (adding in this situation sometime also p-factor) than in X-Plane, and the yaw instead of bank is what you feel the most...

 

On a twin the effects of torque-induced roll and even yaw due to slipstream are less pronnounced.

 

All of this varies with speed, AoA, prop RPM, air density, etc...

 

Risking being biased towards what I now use as my **only** flight simulation platform, I would suggest people who care for / raise this questions and try to discuss how realistic the prop simulation is in this or that simulator, to try the p51d in DCS World - I have never found anything so "perfect", to my feeling of what a powerful ww2 bird is..., but specially because RW p51 pilots also credit it as the closest to real sensation they ever got from a flight simulator. And yes I tried the best offers available for MSFS, etc...

 

Roll-Yaw coupling, gyroscopic effects, all prop effects (torque, p-factor, gyroscpic, slipstream) are considered, taking into account AoA, slips, etc..., and you really have to fly that bird hands ON, but what you get makes sense, when you add or reduce power, when you experiment with different weights/ CoG / weather conditions... not to talk about the effects of the damages you can get from air combat... but thats a different story... I can only bring it for comparison because it is the first prop aircraft simulation I simply can't find anything wrong with!

 

DCS also made me finally accept what I believe to be the right simulation platform for my genre of simmer.... I prefer to have just a couple of highly detailled aircraft, than a bunch of models, nice to see and play with, but so far from reality that the experience of pretending you're flying them for real is null. This applies to X-Plane generic models, to MSFS, etc...

 

Unfortunately the market for this type of products is small compared to the size of the wide-range platforms potential users, and sometimes this great products end-up as a commercial failure, something I strongly hope does not happen with DCS World!

Thanks jcomm, great explanations all around. I can see how the roll effect is diminished due to the effects as you described and I will look at those effects more on my work. I am doubtful that roll is non-existent as Geofa suggests that it is. Plenty aircraft design texts talk about roll effects and dampening mechanisms...the question I have to consider is "how much" and in what regime / power setting / AoA. I'm not asking that question of this forum BTW, I don't expect pilots here to have done a "roll test flight" with data logging.

 

he probably forgot to include additional prop slipstream calculations to account for the asymmetric hit of different aircraft surfaces, tending to:

 

I don't think forgot is the operative word. I base that on my own experience with CFD models and computers are just not ready for real-time CFD computations of that granularity. The best Austin does is a very rough approximation using a 3D "flow field" (see below).

 

 

 

There is a countering force as you see here, but what I get from this conversation is its not strong enough in x-plane and the roll is too much....and if that is the case, then I have ideas for improving the situation on my twins.

 

TomK

Jan, I don't have an issue with yaw in the Baron, don't see or feel any at all. It's the constant roll, or a better way to decsribe it is "teetering" that just doesn't seem right.

 

Image yourself standing on a platform, that's sitting on a cylinder and your trying to balance yourself but you just can't. You keep going left to right, right to left, and so on. Well that's the way the Baron flies, constant rolling and no amount of trim can stop it.

 

Now with my limited experience flying and none in a real plane I still find it hard to believe you can't null out that rolling with aileron trim, just enough to counter the torque roll. We have to do it all the time with our rc planes, does it not apply here as well. I have ruined enough perfectly fine aircraft from torque roll on takeoff, learned my lesson there, but once in flight it's not a constant battle to keep her level, especially in zero wind conditions.

 

And again, no, I will not use the trims in the plane. We have enough stuff available to us today that we don't need to be looking down at some knob to make adjustments. That's too old school and applied many years ago when aftermarket goodies like yokes and trim wheels were not available. The less time I have to take my eyes off where I'm going the better, besides it simulates real flight better. A real pilot doesn't have to "look" down to trim his plane, he knows where it is by feel and makes adjustments. Well I should be able to do the same with switches on a yoke or whatever in a simulator.

 

I tried Toms suggestion to decrese the amount of throw per "click" on a rocker or switch, didn't seem to make much difference, the Baron still rolls (teeters - back and forth - can't be nulled out).

I dont know what to tell you Muskoka. I take off, adjust the roll trim till wings level with my joystick...I tap the trim to fine tune......it flies < 2 degree of roll a minute (tracking roll angle for 5+ minutes now) which is probably better than the real thing.

 

In my flying experience in the MU2, what I do in x-plane is perfectly in line with what I do in the real thing. Take off, (see in my first video) I fly the plane, usually with some roll input to counter the torque, I adjust the roll trim to wings level and then I keep two fingers on the yoke and fly the plane because it just doens't stay perfectly stable hands off....that's not reality. I do the same in x-plane as Jan demonstrates. I will concede that x-plane may roll a bit more (without trimming) than reality, but because I trim it out shortly after takeoff, it just does not bother me.

 

TomK

The Duchess flies with < 2 degrees of roll a minute, no issue there as I stated yesterday, and the trims can be tuned just fine with my Saitek equipment. The default Baron flies nowhere near the same as the Duchess. If it did I wouldn't be wasting my time here.

 

I can fly the Duchess all day long with minimal input from me, still hands on, but minimal work. The Baron is constant, and to me seems "unrealistic", just my thoughts.

 

p.s. Tom, it's not frustration, it's dissapointment. <_< I'm too old to get frustrated, if I do I just walk away. Now dissapointment is something else, you expect or hope to get something, you don't, that's dissapointed. My experience with the default aircraft is "dissapointing".