euler_angles

The J-20 exists in significant numbers, as well. The SU-57 really doesn't.

The default for an F-35 is to be at something like M=0.9 and altitudes of 20-25kft.

I didn't work on this effort, I am just in the same circles with a lot of people who did and still do.

Those are not really F-35 equivalents; they aimed for different points in the design space.

Both Russia and China cannot match the US on very low observable technologies, so they have tried to make the most low observable platform they could and then attempt the air combat problem with different technologies that they ARE good at. The J-20 has doubled down on having very long range, capable air to air missiles, as well as being highly datalinked with other Chinese platforms.

The Russians don't have nearly as good AAMs so they're just trying to be as maneuverable as possible.

I have a much higher opinion of the J-20 than I do the SU-57.

It's mostly a certification issue. There are some hardware changes and integration work that has to be done, but the biggest obstacle is that the certification work is done in and by the US. So there's a diplomatic element.

The Gripen is not a dual-capable aircraft, meaning it isn't certified to carry nuclear weapons. This makes it a tough sell to NATO nations who must align themselves to NATO's strategic goals [0], which call for nations to contribute dual-capable aircraft. Nor is the Gripen independent from US supply chains. It uses the General Electric F414-GE-39E engine.

If you're a NATO nation looking for a non-US jet that can satisfy your dual-capable needs, your only option is the Rafale.

[0] https://www.nato.int/nato_static_fl2014/assets/pdf/2022/6/pd...

I've worked with quite a few people who were part of the AI effort, and my current boss was the architect for ACE a few years ago. All of those people were painfully aware of the gap you describe here and were actively working to bridge it.

But it did the most extensive flight test program for anything in history [0]. I worked on this program for years. I do not think a lack of flight testing is the problem. The problems are many, but in short:

1) Lack of competent, forceful oversight from the program office. DOT&E reports about the F-35 program have, for years, given the program office recommendations that it has failed to follow.

2) A prime contractor (Lockheed-Martin) that restricts access to its data. The F-35 program had to sue LM in federal court to get access to the necessary data to make the Joint Simulation Environment (JSE) fully functional. In the end, the case was settled, but only after six years of battle. The report linked in the parent article describes how maintainers are not allowed access to servicing procedures that they have on other aircraft. I have seen this personally in flight test. Even something like a gear swing requires an LM certified Field Services Engineer to conduct.

3) A completely broken software release process. For many years in developmental flight test, we received software builds that were just entirely broken, as in, the jet would not start with that software loaded. The C2D2 process was advertised as fixing this, but really it was just a new name for the same old fly-fix-fly process. The parent report details entire versions that were skipped in the IOT&E process because they were so buggy. The program could have turned JSE into the final stop for new software builds before hitting the fleet, but it chose to pivot entirely into training instead.

I could keep going. A decade working in a program like this gives you a long list of things to talk about. But I'll stop here for now.

[0] https://news.lockheedmartin.com/2018-04-12-F-35-Completes-Mo...

DARPA's Air Combat Evolution program (ACE) began with AIs fighting each other in a simulated environment in a tournament. Then the winning AI fought against a human (USAF Fighter Weapons School graduate) in that simulated environment, and won. The company that developed the winning AI, Shield AI, has gone on to deploy an AI in an actual F-16 that has flown against a human in trials.

https://www.darpa.mil/program/air-combat-evolution

By the time the signal reaches your GPS receiver, it is below the thermal noise floor of even amazing receivers. But each GPS satellite has a unique pseudo-random code (called a PRN) that is within the signal. Receivers that listen long enough can pick out the PRN and thus the GPS signal.

I'm no GPS expert, I've read some of the theory had enough of a working understanding to deal with tactical navigation systems, but that was in my past. I remember using El-Rabbany's "Introduction to GPS" text.

I have crossed paths with a lot of bad code. They write it faster than I can fix it.

The regime of steadily decreasing F-35 prices as new lots are contracted is at an end [0]. With inflation and the cost-overruns on the Tech Refresh 3 upgrade package, we are in a regime where prices will slowly increase.

[0] https://www.defensenews.com/industry/2022/11/18/f-35-costs-h...

Deep down I am indeed tait_bryan_angles

They all came out of a book that anyone can buy called "F-35: From Concept to Cockpit". That book is a compilation of papers presented at an AIAA conference in 2018.

The F-35 contract was awarded on October 26, 2001. I was in my freshman year of undergrad, 18 years old.

I started on the program in August, 2010. I was 26 years old.

The program has just completed its Initial Operational Test & Evaluation, including its runs for score in the Joint Simulation Environment. I am 40 years old.

My own engineering war stories are just that, stories. Any technical information I gave was taken from released sources only. I am extremely conscious of this

Minor correction, the wire dynamics model was provided by Naval Air Systems Command (NAVAIR), the Navy engineering organization in control of research, development, test, evaluation, and sustainment of Navy aircraft.

I went from doing things like I describe in the blog post, to verifying and validating the most complex electronic warfare simulation the DOD has ever done, to being a developer of one of the enabling technologies of that simulation.

I believe what I do now is important, but getting an issue past test and into the release that's sent to customers isn't nearly as satisfying as "I fixed the tailhook last night, which let today's flight test happen". I miss having an aircraft that I can touch.

I actually still have your personal email address. Expect something from me soon. It took a few years but I work as a developer now (C++, electronic warfare simulator)

Yes, the tailhook bay is very, very small. We had a primary disconnect in the bay for the instrumentation wiring for our tailhook sensors. Any time we had to get at that disconnect without having the tailhook trestle removed, we would call it "proctology".

I have not forgotten your user name here, ha. Yep, been a minute. I should hit you up via email.

As a guy who knows the F-35 and the program pretty well, I think the best Canadian minds on the F-35 are Richard Shimooka with the Macdonald-Laurier Institute, and former CAF and F-35 test pilot Billie Flynn.

Shimooka has a number of works chronicling the Canadian F-35 decision making process, e.g. https://macdonaldlaurier.ca/assessing-damage-canadas-fighter...

Billie Flynn discussing the F-35 and the current state of the CAF on "The Merge" podcast: https://youtu.be/kibWNHr9hdg

The CH-46 has been out of US Navy service for 20 years and Marine Corps service for almost 10, just as a program note.

I abhor war. I believe the only way to secure peace is to be very good at war. That's why I participated in flight testing the F-35, and why I work on electronic warfare simulations now.

I wish I lived in a world where there's no need for any of this, but as far as I know, war is as old as the species.

For F-35 flight test specifically, nothing comes to mind. Perhaps I'm a victim of the forgetting you mention.

There isn't a similar carrier aircraft in the inventory that could have been used, as far as I know.

Absolutely. We had a whole carrier suitability team full of people who lived and breathed this stuff. It was just my responsibility to make sure the aircraft instrumentation system got them the data they needed, at a high enough quality, to empower their analyses and decision making process.

No offense taken. The observation of an instrumentation technician and an engineer (me) definitely counted for not much at all in the grand scheme of things. And we could have just as easily been proven wrong.

We weren’t allowed to have any other real programming tools, and the telemetry “maps” we were trying to make were/are major/minor frame oriented. This maps nicely to a grid of data: a spreadsheet.

IRIG 106, Chapter 4 PCM telemetry covers what we were doing in this process, along with Chapter 9.

Yeah, dynamics will be different, though caveat I am not a structures/loads engineer.

I just don’t think anyone had the risk appetite to chance a test asset against a very difficult to achieve test point.