FBW/FCS issue?

Hi,

In the DCS Flanker's manual that I'm reading, is said in thr FCS implementation section that the FCS would trim the aircraft to keep the given flight path. However, in DCS if you speed up or slow down the plane will react by nosing up or down just like a normal aircraft would. What's happening then? Am I understanding the manual incorrectly? Is the in-game implementation bugged, or the manual wrong? How is it irl?

It is mimicking a naturally stable air craft. The flight path is probsbly not the best translation. Think of it as staying neutrally trimmed as long as you stay at one speed. If you change speed you need to change trim as well usually. If you look close it’s actually maintaining AOA, which is quite different from the pitch laws maintaining attitude in western planes

It is mimicking a naturally stable air craft. The flight path is probsbly not the best translation. Think of it as staying neutrally trimmed as long as you stay at one speed. If you change speed you need to change trim as well usually. If you look close it’s actually maintaining AOA, which is quite different from the pitch laws maintaining attitude in western planes

That would make sense. I didn't notice that it was maintaining AOA but it is true that I could fly it like a normal, stable aircraft

It’s a quirk of the Flanker that kills it for some people who grew up with American teen series sims. For me I enjoy the analog-like feedback to speed differences.

It’s a quirk of the Flanker that kills it for some people who grew up with American teen series sims. For me I enjoy the analog-like feedback to speed differences.

Yeah it certainly feels different. I don't mind it that much, I was just wondering if it was correctly done.

Welcome to the club:yay: reset trim button is your friend

Yeah it certainly feels different. I don't mind it that much, I was just wondering if it was correctly done.

Apparently it is.

It’s a quirk of the Flanker that kills it for some people who grew up with American teen series sims. For me I enjoy the analog-like feedback to speed differences.

For me flying WWII aircraft in other sims, Flankers first in DCS and then the MiG-21 and Tomcat, it's the other way around. Now learning the Hornet, I find the lack of pitch feedback to speed/power change incredibly un-natural and frustrating especially in landing configuration. :joystick:

Hi,

 

In the DCS Flanker's manual that I'm reading, is said in thr FCS implementation section that the FCS would trim the aircraft to keep the given flight path...

The basic underlying FBW system is much like that of the F-15C that we all know and hate (as Su-27 “pilots”). So far you are correct.

However, in DCS if you speed up or slow down the plane will react by nosing up or down just like a normal aircraft would. What's happening then? Am I understanding the manual incorrectly? Is the in-game implementation bugged, or the manual wrong? How is it irl?

If you continue reading in that section, you will see that overlaying this basic system is one which mimics the characteristics of both a static and dynamically stable aircraft. That’s the part that’s confusing you. This is why, if you increase or decrease airspeed, you need to retrim. It’s also why, if you jerk the stick and then let go, after a period of oscillations, you will eventually return to level flight.

The basic underlying FBW system is much like that of the F-15C that we all know and hate (as Su-27 “pilots”). So far you are correct.

How are they similar? Asking of curiousity, not as a smartass. :)

AFAIK they are very far from each other, both in mindset and in function.

How are they similar? Asking of curiousity, not as a smartass. :)

 

AFAIK they are very far from each other, both in mindset and in function.

:) I just knew someone was going to call me out on that statement—especially since our F-15C isn’t FBW. I was simply trying to express the idea that the F-15’s system and the underlying Flanker system are, in essence, trajectory control systems. The aircraft goes where you point it until you make a change. It’s the “value added” programming installed on top of that in the Flanker which forces you to constantly retrim.

As a side note, after all this time flying the Flanker, I don’t even notice that I’m trimming anymore. Just need to replace the flight stick from time to time because the hat wears out. :)

Thanks for the answer Ironhand, it certainly makes sense

Just need to replace the flight stick from time to time because the hat wears out. :)

:joystick: Get a soldering iron and a supply of small tactile switches. No need to replace a $$$$$ stick for the sake of a switch worth a couple of cents