OldRookie

My Feedback: (13)

I have tried most of the gas planes in G3.5, and they all seem to drop the nose when inverted. When I change the cg in the Y axis to get rid if this tendency, nothing seems to happen. The plane will still drop the nose when flying inverted, no matter where I set it. Flying level inverted without having to add down elevator is probably the first thing I trim after setting my trim tabs. How can I trim out the planes when I can't even get the most rudimentary trim set?
I am mostly interested in the Yak. The plane that flies the best so far is the Extra. Didn't care much for the Cap either.
I must be missing something, because I not only think this is a poor learning tool, it isn't much of a game either.
I am less than happy with G3.5 at this point.

Greg

da Rock

What you've encountered is exactly what happens in real life with R/C models. It's not fault of the sim, and any sim that is worth it's salt will do the same thing.

When you trim a model to fly level in RL you wind up with some up trim. It may or may not show as elevator deflection, because of an aerodynamic design feature that is built into airplanes, real ones and real models. They're built with the horizontal tail angled to produce a pitch trim that will fly the airplane level. It's usually set for the expected cruise speed with the expected payload. And to have the airplane fly level, the wing is going to have to fly at an Angle Of Attack that creates the lift to carry that payload at that speed. And that AOA is going to have the front of the wing pointed a bit up. Up trim. So what happens when that airplane, with it's built in up trim goes inverted?

When they go upside down, the horizontal tail is going to do exactly what it did when rightside up. It's going to pitch the nose slightly. Only now, it's going to be pitching it toward the ground, not toward the sky. And what do you have to do to fly that airplane level inverted? Hold the stick forward. Or trim some "down" into it. Exactly what you're seeing the sim do.

OldRookie

My Feedback: (13)

You didn't say a thing that most r/c pilots don't already know.
You should try to address the question I asked instead. As an administrator I would think you would be aware of that.
If you are incapable of answering the question that was asked don't bore me with your explanation of aerodynamics.
Highly aerobatic planes are designed to fly more neutral than the trainers and sport planes you are referring to.
Any flight simulator worth it's salt should be capable, through the trimming process, of getting a highly aerobatic plane to fly as well inverted as upright.

What I am saying is that in real life I can get my planes to fly a straight line upright or inverted with little or no elevator input, simply by changing the center of gravity.
I can't get G3.5 to do this and was asking how this is done.


Greg

da Rock

I addressed the part of your post that bashes the sim for being a poor learning tool and not much of a game.

Sorry I didn't have an answer for all of your post, but I've found that moving the CG in the one model in G3 that I've wished to do so worked as I expected it to. So I assumed that I didn't have the answer for one of your statement/questions.

Hopefully someone will come along and help you out.

da Rock

I've no longer got G3.5 so I checked out what G4 does.

I took the YAK out on the Tarmac field. It's a field that reminds me of an abandoned military field outside of Jacksonville, FL where there were lots of contests back in the day. I've usually got turbulence set, so I turned all that off.

The CG setting on the YAK is 0/1.75/0 as installed. I moved it to 2.75 and then to 3.75 and saw almost no change in the number of clicks of trim to level out the inverted flight. All three settings took about 8-9 clicks of trim for level inverted flight. And when that setting was allowed to remain and the aircraft rolled to right-side-up, the sucker had a strong nose-down desire. However, when I reduced y-axis values, things started to change in the air. The airplane acted with a more and more effective elevator (what you get when you move the CG aft) and the amount of trim needed to do hands off inverted level flight got less and less. And when rolled upright, there was less pitch response to the trim that had been done for inverted pitch.

It really looks to me like the CG movement works like it does in real life. You move it back and what should happen happens.

You move it forward and what happens in real life also happens. Not much that is obviously apparent. Only thing was that the elevator didn't seem to get as sluggish and ineffective as I've seen from other models that had the CG "safely" forward.

Hope this helps you and others who have read all the posts in this thread.