Longitude - what the hell??

[Kenjiro75 59]

So I gave it a try and did my first Longitude takeoff & landing... That was terrible! After takeoff it takes a few seconds for the plane to reach 320+ kts and its system yells "overspeed!". It shouldn't behave like a fighter jet with afterburners on, should it?? And the approach? I was shocked, when the Longitude started to warn me about the stall, when I was flying 160 kts! This is insane! Even an airliner wouldn't stall at 160 kts! And the landing? Eh, I did it like an amateur 😞 So instead of a smooth & pleasant flight experience I felt like I was riding an angry bull in the skies. Totally disappointed...

[DaWu 779]

It’s a frickin default AC. Who cares

[Azapata87 173]

The default AC should at least be flyable especially if they are charging extra money for the "premium deluxe edition". I'm sure they will be fixed in upcoming updates but its a shame that the flight dynamics of some of these airplanes were left in such poor condition for release.

Edited August 29, 2020 by Azapata87

[thepilot 577]

20 minutes ago, DaWu said:

It’s a frickin default AC. Who cares

Me, as long as it's not clear whether it's just a badly programmed FDE for an individual aircraft (and thus salvageable) or a problem at a deeper level, meaning with the simulator engine itself.

Edited August 29, 2020 by thepilot

[Blaze 102]

Yes, it's way overpowered. I've been able to control that with throttle management. Have not encountered the stall issue, with the flaps down. Could be a cool biz jet with a lot of love but your right its disappointing as is.

[Der Zeitgeist 1,575]

The most important thing right now is to go into the weight & balance screen and periodically top up the fuel. 😅

[Ricardo41 5,949]

How do you know it's overpowered? Have you logged pilot time in the real thing?

[Chock 17,769]

2 hours ago, Kenjiro75 said:

the Longitude started to warn me about the stall, when I was flying 160 kts! This is insane! Even an airliner wouldn't stall at 160 kts!

Stalls depend only on angle of attack, not airspeed. It's a misnomer to suppose an aeroplane has a 'stall speed'; what it really has, is a critical angle of attack.

This can be reached as you pitch higher and higher to counter flying slower but still maintain lift. But if you pitch up too much, regardless of speed you can still reach the critical angle of attack. This phenomenon is exactly what makes snap rolls possible; they are effectively high speed autorotations caused by deliberately stalling one wing as you pitch up steep and kick on rudder.

It's worth being aware that in a descent for landing, the downward path of the aeroplane means the oncoming air is coming at the aeroplane from below, and this increases the AoA. This is what causes all those stall spin accidents in GA aeroplanes when people nudge the rudder around in the circuit on the turn for finals. Even skilled pilots can make this mistake if they forget this. That's how James McCudden was killed when his engine quit on take off in his SE5a, and he was one of the highest-scoring and most experienced pilots in WW1, having been an instructor.

Not saying the Cessna in the sim has nothing wrong with it, but if you were in a somewhat flat descent at 160 knots, you could quite easily be getting near the critical AoA, and this will trigger the stall warning.

Edited August 29, 2020 by Chock

[Blaze 102]

59 minutes ago, Ricardo41 said:

How do you know it's overpowered? Have you logged pilot time in the real thing?

In full disclosure "No" I'm not a type rate Longitude pilot but I don't think I need to be to say it's OP...

Okay I'll bite, far from scientific and just for grins, I looked up it's performance on Wikipedia, says 16 minutes to 43K at 33,000lbs probably not max rate. I loaded a standard day at KSAN set the weight  and launched. I was overspeeding climbing through 33K and made FL430 in 6:27 seconds; you be the judge.

Edited August 29, 2020 by Blaze
Removed the snarky rub

[Gazzareth 808]

17 minutes ago, Blaze said:

In full disclosure "No" I'm not a type rate Longitude pilot but I don't think I need to be to say it's OP...

Okay I'll bite, far from scientific, I looked up it's performance on Wikipedia, says 16 minutes to 43K at 33,000lbs. I loaded a standard day at KSAN set the weight  and launched. I was overspeeding climbing through 33K and made FL430 in 6:27 seconds; you be the judge.

 

Obviously very overpowered, unless of course every business jet made from "quality" devs is massively underpowered in previous sims. Early Learjets are known for fantastic rates of climb and it vàstly surpases them, again not scientific - but would very much expect this bird to climb in a similar manner to the Citation X.

 

G

 

[Andreas Stangenes 1,628]

Yes its very overpowered. But I kinda enjoy it for what it is nevertheless. It's very twitchy on approach, and even with full flaps it certainly wont do big manouvers near vref speed without stalling. Also, the takeoff is so fast with full throttle that I hardly have time to click flaps 1, gear up, flaps up before hitting 240 🙂 

It takes me where I wanna go in Onair Company, and it does it with style and speed. I like that. I also love the garmin suite. I like it alot better than the c4. 

Edited August 29, 2020 by Andreas Stangenes

[Dillon 2,197]

24 minutes ago, Andreas Stangenes said:

Yes its very overpowered. But I kinda enjoy it for what it is nevertheless. It's very twitchy on approach, and even with full flaps it certainly wont do big manouvers near vref speed without stalling. Also, the takeoff is so fast with full throttle that I hardly have time to click flaps 1, gear up, flaps up before hitting 240 🙂 

It takes me where I wanna go in Onair Company, and it does it with style and speed. I like that. I also love the garmin suite. I like it alot better than the c4. 

Now if I can only get to KFFC to KISM without a system crash.

[Ricardo41 5,949]

1 hour ago, Chock said:

Stalls depend only on angle of attack, not airspeed. It's a misnomer to suppose an aeroplane has a 'stall speed'; what it really has, is a critical angle of attack.

 

Exactly, and this is why I hate it when folks spread misinformation, because it ruins the fun for everyone: "he, I've been reading that the Citation Longitude is broken, so  I guess I won't play it."

Please, at least google or wikipedia it before you post stuff about airplane behavior you know nothing about.

[Blaze 102]

I fly it quite a bit actually, I just manage the throttle. I understand AOA it has an AOA guage in the MIP.

In all fairness it's got good sounds and I've enjoyed flying it over the last ten days. Hard to get the CG in limits according to the fuel and cargo page without adding a lot of weight to the rear stations.

 

[KenG 492]

1 hour ago, Chock said:

Stalls depend only on angle of attack, not airspeed. It's a misnomer to suppose an aeroplane has a 'stall speed'; what it really has, is a critical angle of attack.

True, stall occurs when the AOA exceeds the critical AOA and this can happen at any airspeed and in profile (nose above or below the horizon.)

However, to say that it is a misnomer to suppose and airplane has a stall speed not quite correct either.

According to the FAA there are a number of stall speeds

Quote

VS   means the stalling speed or the minimum steady flight speed at which the airplane is controllable.

VS0   means the stalling speed or the minimum steady flight speed in the landing configuration.

VS1   means the stalling speed or the minimum steady flight speed obtained in a specific configuration.

VSR   means reference stall speed.

VSRO   means reference stall speed in the landing configuration.

VSR1   means reference stall speed in a specific configuration.

VSW   means speed at which onset of natural or artificial stall warning occurs.

That is a lot of speeds that the manufacturer deal with when certifying the airplane.

Test pilots are able to replicate these speeds through careful flying of the airplane to keep it in the specific conditions in which exceeding the critical AOA will happen at a specific airspeed. 

When training pilots we have to understand how the manufacture developed these stall speeds, because they are printed in the POH or AFM. The Airplane Flying Handbook Chapter 4 helps us in setting up predictable stalls.

Quote

Pilots in training must remember that a level-flight 1G stalling speed is valid only:

• In unaccelerated 1G flight

• In coordinated flight (slip-skid indicator centered)

• At one weight (typically maximum gross weight)

• At a particular center of gravity (CG) (typically maximum forward CG)

Thus if I follow the procedures correctly I should find that critical AOA will happen predictably at a specific speed given the specific conditions.

In some cases the manufacture will even provide charts to compute the predicted speed the airplane will exceed the critical AOA for non-standard configurations.

So as long as I follow correct procedures in setting up the stall I should expect that the airplane will exceed its critical AOA at a predictable airspeed and meet the testing done by the manufacturer's test pilots. 

Why does all of this stall speed talk matter? Because the VSR Reference Stall speed gets used by the manufacturer to establish V2MIN and VREF speeds for take-off and landing.

Here are the simplified approach speeds for the CE 700 posted on the Flightsimulator forums.

So in the landing configuration I should expect at maximum landing weight the airplane should be stable at 125 KIAS. However, the airplane stalls in unaccelerated straight and level flight at 130 KIAS. In accordance with the certification of the airplane with Part 25.125 I should normally expect that VREF should be no less than 1.23 x VSR0.

So while I am not a certified CE 700 pilot, I can look at the performance from the game versus expected AFM performance and determine that something is not right. Then when you look at the aircraft files the CE 700 is missing the aircraft.cfg and flight_model.cfg aerodynamic files and thus in the game the airplane is most likely trying to fly on the 640 surfaces.