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F-35 Lightning II

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Re: F-35 Lightning II

Postby hvengel » Tue Feb 11, 2014 4:19 pm

e-Tron wrote in Thu Mar 28, 2013 5:39 pm:This JSBSim stuff is so hard. I'm having a tough time findind the resources I need to figure it all out. I came across these fixes but I dont understand what they are really changing in the sim. I guess the pushback was not getting initiated, but I don't know what the order of the numbers in the aero/coeff... changes. Just reading console output and digging up answers here on the forum


The index values in a JSBSim look up table MUST be monotonically INCREASING. So

Code: Select all
            <tableData>
              1 0
              0 1
            </tableData


is incorrect because the index (IE. first column0 is deceasing. In older versions of JSBSim the indexes only needed to be monotonic but that was changed to monotonically increasing and I think this happened around FG 2.4.
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Re: F-35 Lightning II

Postby Algernon » Mon Mar 03, 2014 8:07 pm

I've managed to get a basic Flight Control System working [as] realistically [as possible] along two axes (up/down and forward), but only on the YASIM version of the F-35B. And I haven't solved the problem of it wandering off with the wind, either. But it's pretty cool - when the STOVL switch is engaged, pulling back on the stick makes you go up vertically, pushing forward makes you go down. It's very early days, though, watch this space this time next year (still quicker than the real aircraft's development, and a lot cheaper!)
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Re: F-35 Lightning II

Postby Johan G » Tue Mar 04, 2014 9:01 am

Algernon wrote in Mon Mar 03, 2014 8:07 pm:when the STOVL switch is engaged, pulling back on the stick makes you go up vertically, pushing forward makes you go down.

How would you forward and rearward then... (or do you mean the throttle)? :wink:
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Re: F-35 Lightning II

Postby Algernon » Tue Mar 04, 2014 9:16 am

Very interesting question! And one that's difficult to find out the answer to with a brand new and secret aircraft. From watching videos of their simulators, it appears that vectoring forward is indeed controlled by the throttle, but I haven't seen any evidence of it vectoring backwards yet - I assume it can, but I don't know how you control it.

So at the moment, in my FCS, once in STOVL mode, with the throttle at idle, the main nozzle vectors beyond 90 degrees to bring the aircraft to a hovering halt. Opening the throttle tells the FCS to use the main nozzle to get some forward motion - opening it full will bring the aircraft up to above its forward flight stall speed - closing it again, the aircraft will stop itself again. Stick forward and backwards is vertically up and down (I am presuming the the aircraft does not pitch in pure vertical mode, why would it?), stick left and right rolls the aircraft up to 10 degrees for sideways motion.

It's very early days for the FCS, but getting it to hover successfully felt like a significant triumph. Now I just have to make it stay in the same place.
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Re: F-35 Lightning II

Postby RobAndrew » Tue Aug 14, 2018 3:31 pm

Hello there,

I understand this is an old thread, so I don't expect much for an answer. Were there any plans to make a C varient? With a hook and carrier launch compatible? I've been flying the B varient variety and it's excellent!
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Re: F-35 Lightning II

Postby StuartC » Tue Aug 14, 2018 6:08 pm

Plans, a while ago, to the extent of getting a 3d model.
Beyond that it never went any further.
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Re: F-35 Lightning II

Postby RobAndrew » Wed Aug 15, 2018 12:33 pm

Ah, understood. I'm guessing there's no interest in developing Said plans then? If not, I may give it a go myself after finding out how!
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Re: F-35 Lightning II

Postby StuartC » Wed Aug 15, 2018 1:50 pm

Its an Aircraft that not many of us ( at FGUK ) like all that much. That's why development on the B ground to a halt.
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Re: F-35 Lightning II

Postby RobAndrew » Wed Aug 15, 2018 4:11 pm

May I ask why? As the future of the Royal Air Force and potentially the Naval air force as well, I would've thought such an aircraft would have quite an audience, regardless of its specifications and performance. Perhaps it's just me? :P
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Re: F-35 Lightning II

Postby StuartC » Wed Aug 15, 2018 5:05 pm

I cant stand the fugly little fat white elephant. FAR/RN or not. I'll skip this one and wait for the Tempest.
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Re: F-35 Lightning II

Postby RobAndrew » Thu Aug 16, 2018 12:51 pm

Well, Ugly or not it's here! And what's more it's here to stay! Now i won't put any money on it, but I'm willing to bet that with time, more and more people on the sim may want to see more of it, me included. Of course, if they want it that bad, I'm sure they could make it themselves. But I'm probably not going to be the only person revisiting this thread! :lol:

I will also say that that Tempest does look interesting....albeit ambitious :shock:
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Re: F-35 Lightning II

Postby N-SCOT » Tue Aug 21, 2018 11:31 am

For the record, as an FGUKer I do not dislike the F-35 at all.

I'd argue the following points:

1. Most importantly, as one of those projects "too big to fail", it will be a significant part of many countries' air forces, so maintains relevance whether you like it or not.

2. As it will then be a "contemporary" aircraft for many years to come, it would be odd to see it neglected in FG. It is not as if there's no precedent here for a misliked or distrusted aircraft... lol

3. Having a base model at least gives any future dev work a decent start point.

For the record, I'm happy to be onboarded for any paintwork needed,

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Re: F-35 Lightning II

Postby Mikoyan_2129 » Tue Aug 28, 2018 8:26 am

It's true that no matter how unpopular it might be, it is very relevant in today's aviation and is going to become a bigger and bigger part of it, with all of the countries taking part in the program. I just hope there will be some variety left! I'd like to say I'd trust the French to keep doing their own aircraft, but with the current government, I'm less and less sure they're not going to just buy something American. At least, we have the Su-57, J-20 and J-31 to give some more Gen 5 fighters, and let's trust Japan and South Korea to produce their own!
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Re: F-35 Lightning II

Postby Johan G » Sun Sep 09, 2018 4:25 pm

Regarding the flight controls of the real F-35, it seem to be rather interesting and different from the two main other military VTOL aircraft (the Harriers and the V-22).

This post is mostly about the research leading up to them.

The Harriers flight controls follows are a simple concept. Rotate the nozzles with one control, increase or decrease thrust with the throttle, rotate the aircraft with the pedals and tilt the aircraft with the joystick to add horizontal airspeed. Though it is a simple concept it is tricky to fly.

The flight controls of the V-22 are completely different. In short it kind of have a helicopter mode and an aircraft mode. In helicopter mode the thrust control lever is a bit counterintuitive to helicopter pilots, as thrust is increased by pushing, not pulling. This has caused accidents when former helicopter pilots have tried to quickly add thrust by pulling the control in helicopter mode.

There have been a lot of research on VTOL flight controls and FBW both in the UK and in USA, and some research done together. This research also includes the combined effect of control laws and the algorithms for cuing the pilot through HUD or HMD during hover, something that easily is overlooked. This research has lead to some new control laws.

I have listed some resources that might be of interest below.

----
Dan “Dog” Canin Semper Lightning: F-35 Flight Control System, Code One Magazine, 9 December 2015
John Farley Single minded, Flight International, 11 August, 1999 (For those who do not know, John Farley are one of the more experienced initial test pilots of the Harrier.)
Franklin, J. A. and Nicholas, O. P. Collaborative research on V/STOL control system/cockpit display tradeoffs under the NASA/MOD joint aeronautical program, NASA-TM-103910, Jan 01, 1992
Hess, Ronald A. and Gorder, Peter James Design and evaluation of a cockpit display for hovering flight, NASA-CR-18324, Oct 02, 1988
Foster, John D., Moralez, Ernesto, III, Franklin, James A. and Schroeder, Jeffery A. Integrated control and display research for transition and vertical flight on the NASA V/STOL Research Aircraft (VSRA), NASA-TM-100029, Oct 01, 1987

Civilian Flies Harrier with New Control System, 3 min YouTube video
VSTOL Systems Research Aircraft (VSRA) Harrier, 10 min YouTube video
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