Post your questions below, I'll send them to Soji on Skype and then I'll edit this post with the questions and the answers to them.
There's no specific date for this, I'll send questions to Soji as I get them.
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Responses
Question: how long did it take you to develop? Where there any major roadblocks that you can remember?
Answer: I have developed the very first version for escaping from reality of my Ph. D qualifying exam. I was studying almost all day every day and wanted to have some break. The first version was just flying around and was able to shoot some bullets but nothing to destroy. I already had some experience in simple approximated aerodynamics calculations, and that part was easy.
Question: What do you plan to do in the short run / long run for YSFlight?
Answer: The next short-term goal is to integrate the internal data structure of the DNM model with the new one I have written for PolygonCrest. The change would not be visible to the users, but it will make things easier and open up more possible visual effects for me.
Mid-term goals are more ATC communications and terrain generation from real-world data. I am already using YSFLIGHT for my own ILS approach practice. The program reacts good enough. I want to simulate more situations like very congested airspace, changing weather, etc. And, pilots and ATCs work together in such situations.
I have downloaded NASA SRTM data and was able to visualize. What I need to do is down-sample and cluster the scanned-data and then make some part flat so that I can place airports.
Of course I try to address requests that you are sending me. Like multi-color smoke was not at the top of my to-do list for the last version. But I have received very strong requests for this feature. So I added it in the last release.
Among the frequent requests, one of the somewhat-short-term goals is to make damage-tolerance floating point. I think making it integer, and made most of the airplanes having damage tolerance of less than 10 was my bad decision. Just changing int to float is not a big deal, but I also need to change the network protocol and flight record. So, it takes a while to get everything consistent.
Question:OpenYS - What are your thoughts on this project? Where would you like to see the project end up?
Answer: What always amazes me is YSFLIGHT users coming up with a new way of enjoying the program that I have never imagined. I would be happy to see more surprises from the OpenYS project.
Question:Will YSFlight ever be open source? even if it is to a limited few developers? A lot have people have been asking about the possibility of opening the program up - what is your opinion of these requests?
Answer: So far I am not planning to open the source code of YSFLIGHT. But, when I stop the development, I will open the source. I want to keep this fun monopoly to myself for now. Sorry

Question:Do you have a favourite stock map or airplane?
Answer: North Kyusyu map is the newest one I made and I like it the best. My wife is from that area, by the way, and I was born in Aomori prefecture.
My favorite airplane is Concorde. It’s a shame that none of the Concordes can fly even for ceremonial flights. British and French people should be proud of that beautiful airplane, and would be nice to keep a few flyable. My second favorite is A-4 Skyhawk, by the way. When I finish DNM-editing functionality of PolygonCrest, I want to re-make A-4 Skyhawk model.
Question:Have you ever considered allowing aircraft lights that illuminate the ground at night? (taxi/landing lights)
Answer: Yes. I did. And, gave up for now. I need to do it in the fragment shader. However, that means the lighting calculation will be done number-of-pixels-drawn times. So, the computational time will increase by number-of-pixels-drawn times number-of-lights, which will be substantial.
Question: Would you ever implement a more realistic autopilot. Such as a speed hold and a climb to altitude feature with a VS selection?
Answer: Probably. It’s in my to-do list.
Question: Now that $500 computers who could only run YSFlight before can now run FSX, FS2004 and other more advanced flight simulators, what is being done to keep the game relevant?
Answer: First of all, I feel honored that you compare YSFlight with FSX and FS2004. Both FS2004 and FSX were great programs. FSX was too heavy for my 2004 MacBook Pro. But I flew FS2004 very long time especially for practicing for my instrument rating. Also it was nice to be able to fly approaches of my home airports in FS2004. YSFlight then did not have an ATC, and still has only ILS approach, not VOR, GPS, or NDB approaches.
I think it is nice to keep a few free flight simulators in the wild. You can casually download and start flying. If YSFlight makes someone interested in aviation, I am very happy even if the person moves on to another (paid) advanced flight simulator. I love aviation. I ultimately want to make some contribution to the aviation community. I encourage you to visit your nearby airport, meet pilots and ground staffs, and go to air shows. If available, go for the discovery flight and get some official real flying time!
Another concern is death of software. FS2004 was better than FSX because 2004 does not require activation. But, when Microsoft stops FSX activation server, and when your PC or a hard drive comes to its life, you can no longer start FSX. I think the software activation was one of the most horrible ideas in computer history. It may be ok for corporate sales. But, I don’t think it is good for consumer products. In 100 years, there will be some people doing research on computer history. Probably what they do every day will be to crack copy protection to revive ancient computer programs. Even FS2004 may stop working in future versions of Windows. (Does it run on Windows 10? I don’t know.) For ordinary users, it is possible that the favorite program one day suddenly dies. I am sick and tired of seeing sudden death of excellent software. I don’t want YSFlight die suddenly. I am trying to keep YSFlight up and make it available to major operating systems as long as I can.
(TLDR from Varren - Pretty much, YS isn't real competition to FSX ect. but they will eventually die off and he intends to outlive them.)
Question: Salutations Dr. Yamakawa.How is the progress coming on your AI voice project?
Answer: Not much yet. I have written some test code for Windows that reads a sentence. But, there are some more technical challenges. Also I haven’t figured how to do the same in MacOSX. Probably Linux does not come with a standard package for voice generation. So, it has been on hold for now. But, radio communication is one big fun part of flying (although some pilots disagree). I really want to implement it so that I don’t have to pause and copy the direction while shooting an instrument approach. The voice feature will come eventually.
Question: Have you had much contact with the Japanese ysflight community? What about other international communities?
Answer: I have several users who regularly send some comments and feature requests from Japan and Korea. I think these two communities are active. Korean community actually opens a booth in Seoul Air Show. If you have a chance to visit, please stop by their place.
Question: Where do you see YS Flight development five or ten years from now?
Answer: That’s a very good question. For me, YSFLIGHT is an opportunity to learn new programming techniques that I wouldn’t learn in my research work at the university. It is my training to write a program used by large number of users, which is very much different from writing a program for small group of expert users.
Most importantly, YSFLIGHT reminds me of the joy of programming. Writing programs for work is not always fun. Customers throw garbage data at my program, and my program outputs a garbage. It’s called Garbage-In-Garbage-Out. The problem is in the input, but the customers don’t understand and blame my code. After repeating this process over and over again, programming may become just painful and boring. Fortunately to me, because I am writing YSFLIGHT code, programming is still a fun for me. I always tell my students to have a hobby project so that your expertise does not become your pain.
But, I realized that who gets promoted is someone who understands programming, but who doesn’t actually writes programs. I learned it too late after 13 years of no promotion. But, in the current system, I wouldn’t have time to write programs if I get promoted, and I am not trained to do such management work anyway. I honestly don’t understand how my college friends transitioned from research to management. I’ve been stuck with income that is ok for younger researcher, but low for my age. I don’t know what’s going to happen in five to ten years. Ha Ha.
To answer the question, YSFLIGHT does not have a clear direction. When I learn something new and interesting, I add some elements of it in YSFLIGHT. For example, I’m trying to understand machine learning now, which will be good for my work, and should make YSFLIGHT more interesting. I have written an experimental machine-learning based throttle control, which somewhat worked. What I want to do is to let you train your dogfight AI, and let it fly a combat with someone else’s. My friend says it is very much possible, but I haven’t understood how it can be done. Let’s see how much I can understand the concept.