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YASIM Help & documentation

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YASIM Help & documentation

Postby Odeliuus » Mon May 10, 2021 11:46 am

Hello gurus of YASim FDMs!! I am desperately asking for help :mrgreen:

As you may know, I'm trying to improve a bit the FDM of the Hornet Autogiro. I have come across all the YASim README files, the airticle How to: make a helicopter about YASim, Buckaroo's website explanation about YASim for aircraft (I understand it's for aircraft, but that site helped me figure out what many, many parameteres do. I can't thank you enough!), I have read many, many posts in the development forum (including esterile discussions, it was a pain to "quickly filter" posts and comments, and I have opened different FDMs to try and see by myself how they are done and I think that for being my very first time at programming something that flies it's relatively "easy"... it still takes time. Tens of hours of man work have been put into this. However, I'm dealing with a few (yeah, a few LOL) problems that I hope someone can point me in the right direction to solve this:

1. Is it possible to code that when the gyro is closer to the ground the rotor displaces some air down giving the gyro a momentum to land almost hovering? I have been tinkering with various settings in the YASim file but don't seem to find a clear solution.

2. Is it possible to control the behaviour of the thing so when I pitch it down it moves forward at higher airspeed and when I pitch it up it quickly reduces its speed? Right now seems that everytime I cut throttle, the gyro takes a way longer time to deccelerate than it should, which is weird for me. Is this a fuselage drag thing? CG? Intertia tensors?

3. Is it possible to control the resistance for "rudder turns"? Right now it seems that even applying full rudder it's impossible to do a 180 rudder turn (both in the air and ground). I should be able to do donuts when in the ground. Right nowturns are not tight enough.

Thank you, I like autogyros and my final goal is to be able to simulate an autogyro in FlightGear with "payware" quality. Now back to work.
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kaklik

Postby kaklik » Thu Jan 06, 2022 9:53 pm

Hi,
I made two YASim models of UAV autogyros https://github.com/ThunderFly-aerospace ... Gear-TF-G1 and https://github.com/ThunderFly-aerospace ... Gear-TF-G2.

I think that your requirements are beyond of possibilities of the YASim FDM engine. The YASim is quite simple geometry-based FDM. Therefore you could be able to get the behavior that you expect in the particular situation by tweaking the model geometry and parameters, but you probably get new troubles in different situations.
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Re: YASIM Help & documentation

Postby helijah » Fri Jan 07, 2022 8:38 pm

Hi

Just a question Odeliuus, what version of the Hornet are you using? Because the last update is from May 22, 2021 but it is not on FGAddon Stable. Only on FGAddon Trun and in my hangar of course.

http://helijah.free.fr/flightgear/les-appareils/hornet/appareil.htm

Regards Emmanuel
Some planes (and other) for FlightGear
http://helijah.free.fr
and
http://embaranger.free.fr
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Re: YASIM Help & documentation

Postby Odeliuus » Mon Jan 17, 2022 2:19 am

Hello Hellijah, this post is several months old. Now we are using the 3d model made by my friend Murat which is extremely detailed, and part of the original code in the Hornet before that update you mention paired with some new custom code, instruments, a visual 3d checklist you can pop up, a key for magnetos, a couple switches needed for startup and engine stop in-flight, animations for the new model and effects, etc.. next step will probably be creating a custom hand held style radio. We also had to modify some values in the FDM because we used a new engine and a slightly bigger rotor, and also wanted to modify some weird behaviors. I tried to contact you via email but the email didn't get through you I guess because you never replied. Anyway, like I said a couple times to you this project is open for collaboration.. you can find me at: aquinonero.atawa at gmail.com

After flying extensively autogiros in X-plane, I have found many things to correct in FlightGear but they are almost polished. As a side note: X-plane autogiros are not perfect but some are far better than the original Hornet (no pun intended). We expect to have a version up to our standards relatively soon (maximum a year) and would like to have it included in FGAddon if possible, because it will be more complete than the prior version. We don't know how this works and hope your version and our version can coexist in FlightGear's default installation hangar as we plan to use the autogiro for our Virtual ULM Flight School and that would facilitate things for our students and other users who would like to find this sort of aircraft in FlightGear.

Progressive updates will include more complex engine and systems logics, as well as failures based on use time and maintenance hangar to fix those failures or to perform certain inspections after a given period of time. We know this might not be everyone's cup of tea but we aim at having a study level autogiro in which people who are training for their real life certifications can practice, as well as advanced users can have a wonderful time they can't currently have with any autogiro in any simulator.

Cheers, and I hope you stay well my friend.
Last edited by Gijs on Mon Jan 17, 2022 9:06 am, edited 1 time in total.
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