Why don't you guys agree on testing some good FM in X-plane that you both are familiar with in real life?I would be very interested to hear a comparison.Tero

The vacuum will only come with the default fm's which are poor.You can manually adjust parameters-under the weight and balance, controls section, and the right hand joystick parameter that will remove that completely.

Then I'll once again, compare the X-Plane P-51 payware to the RealAir payware Spitfire. I've been up in a real P-51, and give RealAir my vote by quite a margin. Perhaps I can make numerous adjustments, to feel better about it. But at the end of the day, both simulations are just electrons imitating movement. Let's argue what causes lift, ROP versus LOP; and is it pitch for speed or throttle for speed... These too, are never ending debates, just like flight sims! :( L.Adamson

Could it be just that X-Plane can sustain higher frame rates stutter-free and THIS is the main reason your eye/brain gets fooled more easily? furthermore, in my opinion, the higher resolution per pixels FSX can display spoils the illusion of flight, especially because the autogen and the texture details are not to scale.

Absolutely agree re the ridiculously over scaled autogen in FSX. Houses are the size of warehouses, and the tall trees have branches/canopies that are far too big. I always turn FSX autogen off because it just looks wrong, its a real shame that ACES did not get it right!

The same thing happens when I land. It's almost as if I'm just sitting there, even though I'm slowing down from around 90 miles per hour IAS. It's not until I'm close to a round out and flare...............to where the surroundings really seem to get moving again.

I had an instructor back in Europe who told that that moment is when you begin the flare.

Then I'll once again, compare the X-Plane P-51 payware to the RealAir payware Spitfire. I've been up in a real P-51, and give RealAir my vote by quite a margin. Perhaps I can make numerous adjustments, to feel better about it. But at the end of the day, both simulations are just electrons imitating movement. Let's argue what causes lift, ROP versus LOP; and is it pitch for speed or throttle for speed... These too, are never ending debates, just like flight sims! :( L.Adamson

Is the xplane P-51 for the newest version? Even in the beta much has been added to the fm.

L. Adamson....what's your first name?I figure we might could have some fun with this if you're interested and just walk through the process. What RV do you fly? RV-9? Is there one for x-plane? If not, let's make one...I'll assemble it, you can test, I can tweak....let's see what we can get out of an x-plane model. I'm a student pilot currently, but with more than enough time in aircraft to argue I'm competent to voice an opinion and I'm a mechanical engineer also so I tend to be a bit more analytical when approaching flight dynamics and troubleshooting issues. We'll start with a straight (i.e plain gray) flight model and basic 2D panel and leave out any 3D "visuals". This will allow the initial version to be done in a day or two.Most of the flight models in default x-plane are not as thorough as they should be...that is being aggressively addressed as quick as practical. I'm interested in this because flight modeling in plane-maker is physics -based but because you assemble the flight model similar to a 3D modeler, a lot of the physics required to refine the model gets left out by authors and the final product leaves something to be desired. This can leadt to erroneous conclusions of the sims abilities. I'm not saying a person is guaranteed to like x-plane's flight model better, but I am saying that just because a particular model doesn't fly well doesn't mean it can't be done better.If this is reasonable, we could go through the process here...it'd allow many to follow along and see how things progress AND it'd give me the occasional break from my aggressive workload.

What RV do you fly? RV-9? Is there one for x-plane? If not, let's make one...I'll assemble it, you can test, I can tweak....let's see what we can get out of an x-plane model.

Wow, sounds like a nice offer LAdamson (Larry?). It would be interesting to hear what you think of XPlane after trying out a professionally tweaked RV.

Wow, sounds like a nice offer LAdamson (Larry?). It would be interesting to hear what you think of XPlane after trying out a professionally tweaked RV.

That is some offer Tom! I am sure Larry will take you up on it.

That is some offer Tom! I am sure Larry will take you up on it.

:-) Not as bad as it sounds Geofa, basic flight model isn't too bad and I have a decent enough "system" for putting something together quickly. It'll be dull and gray with default instruments, but give us a practical case to publically discuss flight model "feel" and talk about how x-plane works with it.EDIT:...found a few posts on Larry's RV-6A, not RV-9

:-) Not as bad as it sounds Geofa, basic flight model isn't too bad and I have a decent enough "system" for putting something together quickly. It'll be dull and gray with default instruments, but give us a practical case to publically discuss flight model "feel" and talk about how x-plane works with it.EDIT:...found a few posts on Larry's RV-6A, not RV-9

Okay...............in reference to that other post, I had not yet seen this. I've been gone in the RV since last Friday. And yes, it's a 6A.For starters, the vertical stabilizer and rudder are not as tall as newer models. It takes a fair amount of right rudder on the takeoff roll, and a lot more during the last third of throttle. You don't apply power too quickly, or it can get away from you. Rudder is very stiff at cruise speeds, and you'll have to incorporate that into the model. Ailerons are very light and balanced, and pitch is about the same. It's not as sensitive as a Pitt's S2B that I've flown, but far more sensitive than a Cessna 172. I use a constant speed prop, which is great for braking action during the landing sequence. Should I move the blue knob forward to fine pitch too soon, the effect is like slamming on the brakes in a car, and will throw you forward against the seat belts.When applying flaps, the nose pitches down, which is opposite of a high wing Cessna. While the Cessna balloons up, and you apply a bit of forward yoke to compensate, the nose of the RV pitches downward, but you don't use pitch to compensate. In other words, it doesn't head downhill just because the nose is.And back to the C/S prop. Since it has the braking power, my RV doesn't tend to float. I can enter a "tight" pattern at 120 kts, and easily slow to 80 kias for an arcing base to final. 80 kias in the pattern is as slow as I want to be. I'll actually start downhill at 80 & the plane will quickly decelerate to 70 before the flare. I want to be around 70 kias and not below 65 kias in the flare, as speed quickly drops from there. It's only a second or two, and if not done correctly, you'll "fall" through the flare, as it does not want to float. You can compensate with a touch of throttle if desired. Landing in this manner is a rather steep approach. Sometimes I land with just half flaps, and sometimes with full. Flaps go to 40 degrees. My flaps, elevator trim, and aileron trim are all electric.If I was to throw the yoke to the left in a Cessna 172 and release, the Cessna will roll back to the right. Usually even a hair past neutral and then upright. The RV just stays where I let go of the stick.................but I don't remember for how long. This is more along the lines of other aerobatic aircraft.As to the RV's included with X-Plane 9; the planes pitch up with flaps, which of course is incorrect. My RV with it's 180HP engine and C/S prop is a lot faster than the simulated aircraft. It can easily get into the yellow arc, not far from the airport. It also slows down much faster than the X-Plane RV's due to it's C/S prop. I'm easily at pattern altitude (800' above airport altitude) before ever getting to the end of the runway. All in all, it seems to have about three times the performance of a Cessna 172 when doing pattern work, and hence, a lot more fun! It's also quite comfortable for long cross-countries, as I have nice leather seats, two axis auto-pilot, XM radio & satellite weather, in addition to a traffic monitor which picks up reply signals to transponder interrogations.So there you go for starters. Here is a link to pics. The panel has since changed with an audio panel, two radios, and a Garmin 696 which replaced the 496.L.Adamsonhttp://www.classicaerodesigns.com/web/publ...12FDF3F9B8D14A4

Thanks Larry...man that's full stuff but "perfect" description of performance. Recreating all those characteristics would indeed be a challenge. I can see in many of your descriptions why x-plane's flight model COULD fall short. I say could because I haven't perused x-plane's full compliment of controls and input. Indeed I expect several conversations with Austin will come about from it.Take for instance the braking action from the flaps. Flap settings in x-plane "seem" to be represented by a coefficient of lift and a coefficient of drag. This values work in conjuction with surface area and flap deployment angle as best as I could guess.A valid question would be whether or not such a calculated drag value is applied to the Cg of the flight model or at the centroid of the flap. You could see how in one case, the plane with pitch nose down and in the other case not. Now that doesn't preclude modeling the behavior using other means, but I will have to explore some other options....hrm....good stuff! Thanks Larry.

And so it begins. There's a parameter in Plane-maker where you can specify the pitch moment as a result of deploying the flaps. So rather than x-plane calculating the moment by having to do "high overhead"calculations on the flap centroid, he just allows the designer to specify the pitch moment at max flap deployment....probably linearly interpolated.So by specifying a negative value, the plane does pitch down when flaps are deployed. A coefficient of lift value is used to specify lift from flap deployment. So does the RV not balloon (or increase in altitude) in any way when the flaps are deployed?

And so it begins. There's a parameter in Plane-maker where you can specify the pitch moment as a result of deploying the flaps. So rather than x-plane calculating the moment by having to do "high overhead"calculations on the flap centroid, he just allows the designer to specify the pitch moment at max flap deployment....probably linearly interpolated.So by specifying a negative value, the plane does pitch down when flaps are deployed. A coefficient of lift value is used to specify lift from flap deployment. So does the RV not balloon (or increase in altitude) in any way when the flaps are deployed?

From what Larry mentioned it sounds like the attitude in the RV lowers with flaps deployed. On the Baron -10 degrees causes little if any change of pitch-in fact 10 degrees is used by many to slow to approach speeds. (The xplane Baron I have pitches/balloons way up).What might be good for developers like you is to come up with a "checklist" of particular phases of flight and what you need observed.I am first to admit-I just fly the plane-I don't always notice what this and that causes exactly-although I have certain "exacts" for instrument flying-e.g. gear down =500 fpm descent with no retrim, 15" and 2300 rpm = 120 knts. etc. However, when I get in the sim I sure recognize if it feels right or not.

So does the RV not balloon (or increase in altitude) in any way when the flaps are deployed?

No, it does not balloon. The attitude is nose down, as Geof mentioned. You can feel deceleration when applying flaps, but that's a bit tough to simulate, except for decrease in airspeed. I remember an old airliner sim using sound to get the deceleration idea across. It wasn't real, but actually quite effective!L.Adamson

Hi guys, really interesting experiment going on here! My two cents on the "ballooning/pitching down" issue:The effect is also present to varying degrees on the 737 I fly. There is a difference in trim when selecting lower flap angles at first, since mostly the wing area is increased towards the tail - this will shift the center of lift, and therefore more nose-up force is needed to maintain attitude. Increase in lift is negligable.Once you get to 10 degrees and more, the flaps will angle more downwards and backwards. This will result in both the trim and also the lift changing, but also quite some more drag. This feels like the plane pitches down by itself, but with the increase in lift the flightpath will actually stay the same (just stop the nose after dropping a few degrees down). The plane would "balloon" if the nose didn