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Old 07-11-2018, 03:50 PM   #11
nessuno0505
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Quote:
Originally Posted by Nosferatu[whisky 1-1] View Post
Yeah, you basically just need to play around with the trim a lot as you fly about. just as with any aircraft that doesn't have FBW or AP.
Not exactly. L-39 has no FBW nor AP, but is a lot more easy to get properly trimmed and fly almost straight and level without your hands on the stick. Moreover, F-5 has got stability augmentation channels while L-39 don't. Nevertheless, F-5 is a lot more difficult to properly trim than the L-39. Maybe F-5 is done such way, I'm not saying there's a bug or ED module is wrong. But it's a matter of fact you have to work more with F-5 trim than many other modules (obviously if you get a-10c and switch AP on you fly straight and level, but that's not the matter of this topic).

Last edited by nessuno0505; 07-11-2018 at 03:53 PM.
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Old 07-11-2018, 07:10 PM   #12
probad
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Originally Posted by Idle_Wild View Post
Second person takes the first peron's statement about continuous trim adjustment literally. Clearly has no idea what a trim is for, if you had to adjust the trim continuously it would be pointless having a trim at all.
you're not even trying to comprehend what he's saying.

here's the deal: air's behavior and the resulting airplane's behavior changes with airspeed. the f-5 has no assistance for compensating with this unlike the carefree trim scheduling that compensates for airspeed variations that the f-15 and fbw aircraft have.
so while yes, for a set constant airspeed, there is a trim that allows for stable level flight, this is a relatively delicate equilibrium point that can be upset by the most minor deviation. any pitch deviation will result in descent or ascent, which results in an acceleration or deceleration, invalidating the originally set trim. likewise, any throttle state mismatch with trim will also result in an upset.
the "problem" is that trim here is graduated in steps, so for your given airspeed, the correct trim angle may be in between two attainable trim steps. theoretically you can set a desired trim angle, and then adjust throttle for equilibrium (no different than the landing technique of aoa for speed, throttle for altitude), though the f-5 in particular has poor spooling and acceleration characteristics that will frustrate this.

in other words, true equilibrium state in the f-5 will be practically impossible to obtain. get used to handholding the aircraft.

Quote:
Originally Posted by nessuno0505 View Post
Moreover, F-5 has got stability augmentation channels while L-39 don't.
to my understanding, stability augmentation here does not mean the f-5 has a system that helps you maintain level flight. instead they are limiters to keep aircraft behavior predictable and useful in maneuvers.
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Last edited by probad; 07-11-2018 at 08:43 PM.
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Old 07-11-2018, 10:12 PM   #13
lmp
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I can trim it out to fly straightish and levelish enough for me to look down into the pit for a moment and not find myself spiraling into the ground once I look up. In a nimble fighter without FBW I don't expect to fly hands off for any extended period of time. One thing that helped me was to set a small deadzone on my stick - since it's old and somewhat wobbly in the center. See if you don't have that problem.
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Old 07-11-2018, 10:39 PM   #14
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Quote:
Originally Posted by nessuno0505 View Post
Not exactly. L-39 has no FBW nor AP, but is a lot more easy to get properly trimmed and fly almost straight and level without your hands on the stick. Moreover, F-5 has got stability augmentation channels while L-39 don't. Nevertheless, F-5 is a lot more difficult to properly trim than the L-39. Maybe F-5 is done such way, I'm not saying there's a bug or ED module is wrong. But it's a matter of fact you have to work more with F-5 trim than many other modules (obviously if you get a-10c and switch AP on you fly straight and level, but that's not the matter of this topic).
F-5 is by design more unstable. In my opinion DCS does a great job to reflect this difference between the jets.
Quote:
Originally Posted by lmp View Post
I can trim it out to fly straightish and levelish enough for me to look down into the pit for a moment and not find myself spiraling into the ground once I look up. In a nimble fighter without FBW I don't expect to fly hands off for any extended period of time. One thing that helped me was to set a small deadzone on my stick - since it's old and somewhat wobbly in the center. See if you don't have that problem.
+1
I think the hardware has a big influence here and might even be the issue. I switched from an old cheap stick to a better and new one. Night and Day.
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Old 07-13-2018, 12:59 AM   #15
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I have used the X-55 rhino stick for 2 year + and I have great results flying the F-5E you have to continuously trim for hand off flying ...
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Old 07-13-2018, 03:29 AM   #16
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Don't forget that real trim in an AC is designed to minimize the force required on the stick/yoke to easy fatigue while flying for long periods of time. Real world you get the AC level with external reference cues (ie the horizon) in day time (and the instruments at night), and then trim to reduce force on the stick.

Real world, you'd level out, trim to something comfortable and make very minor corrections to pitch with the stick almost without thinking about it. Sort of like when you drive, you get in the your lane, and you stay there without having to really think about it. Why do you need to fly hands off for long periods? You're not taking sextant shots, updating charts, etc. You're in a short range high performance fighter.

One of the biggest transgressions sim pilots make in real AC (and I know from personal experience) is paying WAY too much attention to the instruments over what's outside the window. If I can see the horizon and we're level do I need to stare at the ADI? Conversely most simmers have little trouble picking up the instrument scan required to fly IFR.
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Old 07-15-2018, 04:21 AM   #17
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Looks like a lack of trim resolution to me, either in the DCS version and/or in the real one as well. The DSC F-5 would fly perfectly level IMO if trim resolution would be higher.

One click and she immediate very subtle climb (e.g. at 250kts), one click in the other direction and she starts a very subtle descent.

I've flown a French GA plane with an all-moving horizontal tail (like the F-5) and it was almost to impossible to trim for level flight for the same reason
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Old 07-15-2018, 11:36 PM   #18
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Remember that speed plays a role in trim as well. As you go faster, the more exaggerated the aircraft response will be to control inputs. Ask someone who's flown a T-38 how much of a pain in the ass it is to trim for level flight at high mach numbers. I suggest slowing to 350-400KIAS at around 15,000 and practicing basic aircraft handling drills to include trimming for level flight. Try some 30 degree level turns, steep turns, vertical S etc. Slow down and configure and practice some traffic pattern stalls and the like. These full fidelity modules are really pretty good and you need to get a feel for the airplane before you try and employ it.....just as you would in real life. Once you get used to the F-5, she really flies pretty sweet.
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Old 07-16-2018, 05:23 AM   #19
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Quote:
Originally Posted by Midnightzulu View Post
I suggest slowing to 350-400KIAS at around 15,000 and practicing basic aircraft handling drills to include trimming for level flight.
Well, (at least) I can't even trim the F-5 for level flight at an even lower 250kias.
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Old 07-16-2018, 11:31 AM   #20
Nosferatu[whisky 1-1]
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Trim isn't supposed to act as an altitude AP, you're supposed to fly the plane...
The purpose of trim is to make flying easier on the pilot
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