Creating more realistic Polars for the PAR files.

[Looee]

I've been away from this site for a while, actually the login process has been anti-intuitive, and then I've retried to register...

At any rate I'm sort of pre-empting Treehugger on this post, maybe not, But, what I'd like to see is an easy to use slider button type GUI program that set's up proper and accurate airfoil profiles for each flight surfaces for the PAR Polar file. (This could also have a Reynolds # adjustment for size also...) They have something similar for Motocalc 7. Maybe it could be bundled with the next release of FMS? (Hint, Hint,..)

Something else that might interest Michael and Roman. Have either of you looked into improving the stall characteristics in FMS 2,85 by introducing a "noise" factor to the AOA of the airfoil? Basically it would be like having the Lift to drag, coefficiencey of lift and the C/L start to randomly jump around in increasing amounts as you go beyond the stall point. I mean isn't this what happens in real life to an airfoil?

I take some fairly large liberties with the Polars in my own models. I try to be as accurate as I can, but there's still a lot of guess work and trail and error. Some sort of Polar generater that allows you to select the camber, thickness, LE radius, and also allows for airfoils that transition from the root to the tip, would be a boon for creating better airfoils to match our models.

I don't know how much additional coding would have to be added, and maybe you're allready considering this. But as a long time user, and booster of this freeware sim, it would be nice to see a bit more flight realism as FMS matures.

Anyways, just some thoughts.

Best Regards

Lewis Schroeder

[TreeHugger]

Hi Lewis!

Hmm - I had to look up "pre-empting" and dictionary.leo.org says, it is a first-buyer option in a contract (Huh?). No matter what, I'm going to buy it all and swallow the bait...

I tried to start discussions about the polar section on rc-sim and rc-network, but without much success - either nobody cared or nobody knew. My assumption is this: The ones who get hooked up enough to start questioning airfoil data desert towards one of the commercial sims sooner or later.

All I ever heard about polar creation by software is the magic word "xfoil". I'm not willing to get my head around operating a command-line tool, and the grafic user interface "profili" is a commercial release and too expensive for my needs. You probably know that Masuoka Hideaki's par-editor does calculate polars depending on camber, thickness, etc.? On the "polar" page, it's "write calc data". I do have some reservations against the results, those curves just look way too smooth and perfect...

About further development of FMS: I don't see the signs of any, can you?

When it comes to choosing an airfoil for one of my own models, I simply pick one of the limited choice I found realistically looking - no science at all. Your trial-and-error approach seems to be rather successful, since your models always fly as expected (although this is quite contrary to what the majority seems to expect )

If you have more luck poking around the issue, I'm always eager to hear the news!

Kind regards,
Frank

[Looee]

Hi Frank,

Well when we discussed polars on the RC-Sim forum you mentioned a bit of envy of the digital"noise" component idea for a more accurate stall that I thought could work. I assumed you'ld just go to this forum and mention it. Actually I really was hoping that someone would as I've had little time for the forums I do visit. Now it appears that any FMS development is in statis or maybe even has been forgotten, which is sad. There's lots of folks still using this sim and lots of new sceneries, what with the panaramic views and whatnot.




That I know nothing about building data command lines for sims or programming for that matter, doesn't seem to stop me from dreaming up ways to improve what I've already got. I mean look at the extended life RedBaron 3D has because of a bunch of gamers who love the game.

I'm also a bit of an optimist concerning FMS's current status, although you're corect that the development of the sim has taken a bit of an extended holiday, and that there's no more "development" forum.

How does one get a hold of the Moellers? Does anyone at RC-Sim do sim development? Has anyone had any communication lately with the Moellers?

I don't know, you'ld think that they would care a bit more...