Flight model

I found something weird...Power idle, air-brakes deployed, diving at 90°, I'm loosing speed ! Is it normal ? because it's the first plane in DCS that can loose speed in dive (or I'm missing something), it's impressive if it's real !

The M2000 is also a very light aircraft... For who have the habit of flying F-15 or Su-27, the M2000 is an totally other world... I don't say the current Flight Model of the M2000 is perfect, but think out of what you believe "what is normal", since the M2000 is in a very different category.

This is physics 101 guys. Terminal velocity is different for any object falling in the atmosphere you can't assign an arbitrary value of 500km/h and say that's the limit.

Exactly. There's also the fact that the atmosphere changes as you fall so the terminal velocity decreases during the fall. It's never constant, unless you are in a vacuum, in which case it's approaching infinity, because there's no resistance.

This sentence makes absolutely no sense at all. An object accelerating in free fall will keep on accelerating until it hits the ground. (If there is no atmosphere to slow it down) This is physics 101 guys. Terminal velocity is different for any object falling in the atmosphere you can't assign an arbitrary value of 500km/h and say that's the limit.

You are wrong, unless we are at very great altitude...

Your drag raises with x4 vs the verlocity you fall, hence the Max 500 km/h

It increases as the square of the velocity, not x4, and that's for subsonic values. It also depends on air density, so the actual force applied to the object will naturally cause terminal velocity to vary based on altitude.

Just saying:

https://en.wikipedia.org/wiki/Speed_skydiving

So 500km/h may be true for skydiver.

But take a look at formula...

That's awesome CptSmiley. :)

Okay guys, I took a very quick flight and I can definitely say something is wrong. For full transparency, depending on the FBW mode the rate limit on the servo-actuators in anywhere between 60 to 120 deg/sec. It appears I messed up a decimal point causing it to move 600 to 1200 deg/sec for all purposes, is nearly instantaneous!

 

Just took a flight with the fix and things behave much better. That isn't to add with the FCS the stop/start on roll is very fast but not as quick as you guys are all seeing. Also the return to steady state is a tad softer due to the now correct physical limitation on the servo movement.

 

Thanks for all the detailed feedback everyone.

Excellent, that's exactly what I observed and thought was causing the lack of inertia, glad to hear its fixed internally! :thumbup:

Okay guys, I took a very quick flight and I can definitely say something is wrong. For full transparency, depending on the FBW mode the rate limit on the servo-actuators in anywhere between 60 to 120 deg/sec. It appears I messed up a decimal point causing it to move 600 to 1200 deg/sec for all purposes, is nearly instantaneous!

 

Just took a flight with the fix and things behave much better. That isn't to add with the FCS the stop/start on roll is very fast but not as quick as you guys are all seeing. Also the return to steady state is a tad softer due to the now correct physical limitation on the servo movement.

 

Thanks for all the detailed feedback everyone.

Nice...i will happy to fly with this fix. Happy new year! and thanks for the mirage for all Razbam team! i understand that is a beta version and i´m happy to can see the development progress of your beautifull module. :thumbup:

Congratulations very professional, this plane is just like that superbe.:thumbup:

@+Mad

Okay guys, I took a very quick flight and I can definitely say something is wrong. For full transparency, depending on the FBW mode the rate limit on the servo-actuators in anywhere between 60 to 120 deg/sec. It appears I messed up a decimal point causing it to move 600 to 1200 deg/sec for all purposes, is nearly instantaneous!

 

Just took a flight with the fix and things behave much better. That isn't to add with the FCS the stop/start on roll is very fast but not as quick as you guys are all seeing. Also the return to steady state is a tad softer due to the now correct physical limitation on the servo movement.

 

Thanks for all the detailed feedback everyone.

:thumbup:

I thought in AA FBW mode maximum roll rate was 270°/sec?

Okay guys, I took a very quick flight and I can definitely say something is wrong. For full transparency, depending on the FBW mode the rate limit on the servo-actuators in anywhere between 60 to 120 deg/sec. It appears I messed up a decimal point causing it to move 600 to 1200 deg/sec for all purposes, is nearly instantaneous!

 

Just took a flight with the fix and things behave much better. That isn't to add with the FCS the stop/start on roll is very fast but not as quick as you guys are all seeing. Also the return to steady state is a tad softer due to the now correct physical limitation on the servo movement.

 

Thanks for all the detailed feedback everyone.

Just out of curiosity when can we enjoy the new "fixed" version?

Yep, that is the aircraft roll rate. I'm sorry if I wasn't clear enough but the rate I was discussing was the servo-actuator movement rates that dictates how fast the control surface itself moves.

Yep, that is the aircraft roll rate. I'm sorry if I wasn't clear enough but the rate I was discussing was the servo-actuator movement rates that dictates how fast the control surface itself moves.

So with this tuned we now roll 270 °/s and not blacking out if we do a half roll?

Okay guys, I took a very quick flight and I can definitely say something is wrong. For full transparency, depending on the FBW mode the rate limit on the servo-actuators in anywhere between 60 to 120 deg/sec. It appears I messed up a decimal point causing it to move 600 to 1200 deg/sec for all purposes, is nearly instantaneous!

 

Just took a flight with the fix and things behave much better. That isn't to add with the FCS the stop/start on roll is very fast but not as quick as you guys are all seeing. Also the return to steady state is a tad softer due to the now correct physical limitation on the servo movement.

 

Thanks for all the detailed feedback everyone.

Thank you Cpt. Smiley for all of your work! The plane is already very enjoyable the way it is, it will be great after the change!!

So with this tuned we now roll 270 °/s and not blacking out if we do a half roll?

The roll rate was always 270 deg/sec and will keep on being that, what he's talking about is the actuation speed of the servos for the flight surfaces - i.e. the flight surfaces were moving too quickly, leading to a lack of inertia in rolls and an unrealistic feel to the FM.

Smiley already knew about this and had it fixed long before the release internally, but a apparently a mistake was made for the release version with a wrongly placed decimal point resulting in servo speeds 10 times higher than normal :)

The roll rate was always 270 deg/sec and will keep on being that, what he's talking about is the actuation speed of the servos for the flight surfaces - i.e. the flight surfaces were moving too quickly, leading to a lack of inertia in rolls and an unrealistic feel to the FM.

 

Smiley already knew about this and had it fixed long before the release internally, but a apparently a mistake was made for the release version with a wrongly placed decimal point resulting in servo speeds 10 times higher than normal :)

Ya I understand it now I think this change will make the plane even more enjoyable to fly can't wait

Sustained & instantanous turn rate tested, both are way too low compared to real life values.

Dunno how you managed to get too high figures GGTharos...

Sustained & instantanous turn rate tested, both are way too low compared to real life values.

 

Dunno how you managed to get too high figures GGTharos...

Have you tried turing off the FBW spin switch?

You can do some crazy turns with that

The discussion about lack of inertia, I agree with. FBW or not, it is not possible for the FBW to react at the same time as when physics acts on the air frame (if it did, it would have to mean that FBW can predict where aircraft will be moved, in order to counter-react this force, which is not possible). There must always be some time delay when force acts on air frame, and FBW and control surfaces to react. So I think the FM needs tweaking by first, adding time needed to move the control surfaces (right now they are instant) and second, needs to add small time delay for FBW to react on air frame movement adjustments. That I think will add the missing natural flight characteristics that I also feel is missing.

Kuky is correct in this. I can't comment on the Mirage but in the F-16 the leading edge flaps are controlled by a flight computer. While the actuation rate of this flap is 25 degrees per second, there is a 0.136 second lag before the command has percolated through the flight computer. Similarly, the Viper's aileron and rudder slew rates are 80 degrees/second and 120 degrees/second with first-order lags of 0.0495 second.

It is well known that other pilots transitioning to the F-16 can often tail strike on their first takeoffs because they command pitch but there is a noticeable delay before the aircraft responds, so they pull harder and then finally the response kicks in. This is a pig to model in-game, but a circular buffer of responses after the lags works ok for me (again, in a different simulation) - although there might be a better signal processing way of handling the lag.

Anyway, something to think about - although I'm sure it'll freak out sim users who don't anticipate this lag in their FBW aircraft.

Not sure if this should be a separate thread, but has anyone tried flying with the slats disabled? I just gave it a go and to be honest, I was expecting a more substantial difference. Landing speeds and AoA seemed (to my Mk1 eyeballs) more or less the same as with the slats deployed.

Landing speeds and AoA seemed (to my Mk1 eyeballs) more or less the same as with the slats deployed.

IIRC, slats are automatically disabled when gear down, so it's possible you tested with slats disabled all the time, unless you manually deployed them.

Some great insights in this thread!

CptSmiley, thanks for making the Mirage so fun to fly!

Two more good videos that can provide some feedback about the flight performance - inertia during roll .

At the beginning of the First video S530 symbology can be seen, the missile circle apears much smaller than the simulated from razbam. Also the vertical dashed Line indication for the vertical CCM looks to me lengthier. Perhaps some cosmetic changes can been also made (keep in mind that the tapes are from HAF Mirage 2000eg RDM - not RDI).

[ame]

[ame]

What about the F15C that we have, it incorporates a FBW system as well, no?

It is not the same at all...