Prop animation question

[expat]

One of my favorite FSX payware aircraft (and the one I would have IRL if $$ were not an issue) is the Pilatus PC12 (Flight1). No matter which spin_prop.bmp type texture I swap out the motion of the prop inside and out is such that instead of a steady rate of spin in one direction it kind of rocks and jerks back the other direction once or twice a revolution. Spoils an otherwise good experience. Is there a tweak in the [propeller] section in the air.cfg to fix/adjust this or is it in the model and can't be changed?

[X_eidos2]

If I remember correctly from my development days, the quirky prop animation is part of the FSX code, not the result of the modeler's work. I got so annoyed with it when making the movie about the DC-2 Uiver, that I took a rather radical process to overcome it. I first changed the alpha in the prop texture so that the prop disc was completely invisible. Then I created a model of two prop disc with a rotation animation in gmax, and exported them as a separate model. Then when I played back a flight that had been recorded using the FSRecorder module, I had the prop model fly along in close formation with the model of the DC-2. It worked pretty well except for a couple of places where I wanted to show the props slowing down.

[Paul Anderson]

In the aircraft.cfg you can have an entry in each fltsim section for 'prop_animation_ratio = 1', it's usually not there because that's the default.
Add the line if missing, then try values of .9, .8, .7, 1.1, 1.2, 1.3. etc. and test to see if cures.
If it works, copy the line into the other fltsim sections.
If not, nothing ventured, nothing gained.
Good luck.

[napamule]

Prop Animation Ratio:
Here are some actual values for various AC. But, 'Trial & Error' is the only way to get it 'right'.
(PC-7: prop_anim_ratio= 1.72). (Cessna 195: prop_anim_ratio=2.7). (Howard DGA-15p: prop_anim_ratio= -1.76). (Sikorsky S-40: prop_anim_ratio=1.76).
This line goes in (fltsim.x) section, right after 'texture= ' line, and is the correct location. It does NOT go in the (General) section.
Chuck B
Napamule

[expat]

Thanks for the replies. Will give this a try and report back.

[Paul Anderson]

Napamule's spelling is correct, not mine.
That's what I get for relying on memory.
Didn't help that I found an example in the Osprey aircraft.cfg that had the full word animation, perhaps FS9 spelling or misspelled to disable.

SDK:

prop_anim_ratio

The ratio of rotor revolutions rendered to the actual revolutions in the simulator.

Bell 206B JetRanger( prop_anim_ratio=-1.76 )

[napamule]

Paul,
Ha ha. When I entered the line in FSX for the Bf109 I spelled it '_animation_' and had to go back and change it to '_anim_'. So I did it too. Habit of spelling correctly (since 5th grade-hehe). The Bf109 prop was showing '3 blade prop still' (blur). So I added line and made it '= 1.23 and it looks better, but I'm not done with it as I think I should try other values (0.5, 0.7, etc). The SDK is not always the last word. Sometimes you just have to experiment on your own with 'horse sense' values to get results. I do it all the time. In fact I spend TOO much time 'touching' EVERYTHING. Every switch. Every button. Every menu option. Too much monkey business, but that's simming.
Chuck B
Napamule

[expat]

Well, in the end no amount of applying different animation ratios cured the problem of the jerky movement. A lower value would just slow the time between faster or jerkier rotation cycles. I found another spin_prop texture that is more subtle and applied that. The movement is still there but less noticeable.

[mal998]

I did some research on prop animation a while back. According to what I found the animation fixes are not applicable to FSX, only FS9.

Have a look at the SDK under the propeller heading. There are several areas that can be adjusted.


Example:
propeller_moi Propeller moment of inertia, (slug ft2).

Aircreation582SL( propeller_moi= 3.000 )
Beech Baron 58( propeller_moi= 6.9 )
Beech King Air 350( propeller_moi = 24 )
Cessna Skyhawk 172SP( propeller_moi= 5.0 )

[expat]

Helpful. Thanks Mitch!