Donstim

No, this video does not show how to fix floaty planes. It shows how to fix a bug that was introduced in one of the early sim updates that was fixed fairly quickly by Asobo.

Yes, that's FBW. That video was made by just using the Windows 10 Xbox Game Bar function. You can enable it by going to Windows settings, Gaming, and turning on the Xbox Game bar. You can then start recording by simultaneously pressing the Windows key, Alt, and R. Or to get more features, you can download and use something like OBS Studio. It's free and open source. https://obsproject.com/

Again, not a problem for an airplane with a good flight model...https://1drv.ms/v/s!Ajsy7Ey4_8uF0EBphYlfTEQ44ZbT?e=hCCfN5

There's no "hack" needed that will have to be removed if there are changes to the ground physics, and no additional money needs to be spent to model crosswind takeoff/landing capability right now as I showed in the video linked above.

MSFS has its issues, but they can be overcome.

As RaptyrOne said above, the timing of the MCDU approach phase selection will not cause this to happen. It is more likely a control binding or livery as RaptryOne suggested. What does the FMA say when this problem occurs. Is it still in SPEED mode, autothrust on, and thrust levers in the CLB detent?

That is definitely odd behavior. If you could provide a screenshot of the PFD when it first occurs, or even better yet, a video, it would help in tracking it down.

As I stated in the parenthetical, I was specifically commenting on your FBW A32NX performance assessment, where you suggested that the OP in that thread try taking off from sea level and climbing to FL350. Regardless of whether you would still be considered "on time" in your ops, or whether or not it is "worth it" to fly faster just to make up 6 minutes, the figures you gave that OP for comparison were incorrect. If the user had actually used that information to do their comparison, they would have concluded (incorrectly) that the FBW A32NX climbs too fast.

Hey Rick, As a performance guru, you should know that using CEO performance for a NEO is not going to be valid. (I'm talking about your FBW A320NEO performance assessment.) It only takes 23 minutes and 148 NM for an A320NEO/Leap 1A-26 to climb to FL 350 starting at 76 T with a 250/300/0.78 speed schedule at ISA+10 C, 33% CG, A/C on normal, and A/I off. For an A320CEO with CFM56-5B4 engines, it takes 29 minutes and 192 NM for the same conditions.

The "normal takeoff data" you are referring to does not include any obstacle clearance considerations. That would have to be done on a runway by runway basis. It does include consideration of 1st and 2nd segment climb gradient requirements. These are minimum climb gradients (not having anything to do with obstacles) that must be obtainable in these segments with one engine inoperative. For a twin, that would be positive first segment gradient (which is not usually limiting) and a 2.4% second segment gradient. I'll repeat what I said before and clarify for you. Boeing does not conduct specific flaps up takeoff testing, which would include Vmu tests, rapid rotations, etc. They would not be able to produce the "normal takeoff data" for approval of flaps up takeoff operations. There is enough data to go back and make some reasonably good estimates, basically using much more refined versions of the "back of the envelope" calculations that have been presented here. (BTW, I am an actual former Boeing performance engineer.) It's a good thing their analysis matched your level D sim since it's from much of the same data. It doesn't mean that any takeoffs were actually conducted in a real airplane with flaps up.

An interesting exercise, 😀. But, since you invited anyone to comment on errors in your back of the envelope calculation... Thrust does not increase during the takeoff roll. It decreases with increasing airspeed, so assuming a constant thrust at the rated static thrust level is optimistic. A fall off of about 20% between 0 and 160 knots would be in the range I would expect to see. So, not accounting for rolling friction is not offset by your thrust assumption, making the calculation even less accurate. It is difficult to know what an appropriate flaps up lift coefficient would be since there may be tail clearance issues in trying to achieve the CLmax determined for the airplane with flaps up. In other words, you may not be able to achieve the angle-of-attack to reach CLmax. Your assumed CL may be okay, or it may not be. Your drag coefficient looks a bit optimistic as well. The liftoff speed for a 737-700 with flaps 1 at 160,000 pounds is around 150 knots, so I would expect the liftoff speed with flaps up with some considerably higher (unknown) weight to be significantly higher than your estimated 156 knots. With lower acceleration due to the errors in accounting for thrust and drag, it looks like your back of the envelope calculation shows this to be a very doubtful possibility. As for @Stearmandriver's comment that accounting for an engine failure means a greater than 50% loss of performance, well that's only for the portion after the engine failure occurs. You don't have "twice the performance" for the whole takeoff. V1 and VR are only separated by a couple of knots for a minimum balanced field length takeoff for the -700. These comments aside, I do agree that this is a fruitless exercise, both in terms of evaluating MSFS flight physics and the PMDG flight model. There is no reason for PMDG to investigate flaps up takeoff performance at all since it is not an approved flap setting. (This same reason also applies to Boeing. No Boeing test pilot would ever have attempted this, and there would not be any flight test data to determine takeoff parameters for a flaps up takeoff within Boeing. The only reason this would ever be looked at would be for an accident investigation ( for example, if someone tried to takeoff off with flaps up out of London City at well over MTOW). http://libraryonline.erau.edu/online-full-text/ntsb/aircraft-accident-reports/AAR89-04.pdf

Try this: https://forums.flightsimulator.com/t/fbw-i-need-help-power-loss-on-engines-after-take-off/515412/31?u=awareplot117729

Take a look at this description from an A320 pilot. The A320NEO with Leap 1A-26 engines has a lot of thrust at idle and causes this. The normal procedure is to let the airplane accelerate to 25-30 knots (when on a straight taxiway) and then apply the brakes to bring it back to around 10 knots. Repeat as necessary.

The flat rate temperature near sea level (KSAN) is 44 C. So if you are not setting a Flex temp above that, you are getting full TOGA thrust. Likewise the THS setting from the calculator is incorrect for the NEO as are the markings on the cockpit pedestal. You should be using the chart at the bottom of the FBW checklist (https://github.com/flybywiresim/manuals/blob/master/pdf/A32NX Documentation/FBW A32NX Checklist.pdf) although there is no need to enter the THS setting in the MCDU. Reaching Vr before the end of the runway is not a good check!🙂 You should be at or above 35 feet by the end of the takeoff distance at V2 after having the engine fail one second before V1 on a continued takeoff.

Maybe, but not to use this calculator as is. It isn't even close to accurate for the A320neo/Leap 1A-26.

Reverse thrust cannot be used in the landing distance assessment for a dry runway, but would normally be used for any other condition unless they are unserviceable or there is some other reason not too use them.

That's in the process of being updated. Wait till you see the update!

What is the source of this information? The length of the takeoff roll depends not only on the takeoff thrust being used, but also on the takeoff speeds. The takeoff speeds vary with the runway length, pressure altitude, OAT, and airplane weight. There is no way that the takeoff roll takes the same amount of time for every takeoff, though use of Flex may lessen the differences some. The FBW A32NX does simulate Flex now. It is simulated for engine thrust output for the A32NX. Although we are working on it, it will be some time before this happens. Re #3 first, with respect to MSFS I've often wondered this myself. MSFS pilots usually don't have to worry about failures during the takeoff that would jeopardize safety and necessitate the use of a correct V1, nor more than a minimum VR and V2. I doubt that the typical MSFS pilot would even know what V1 is for. But I understand the desire for the feeling of realism even if not all the realism aspects are there. For #2, these calculations are required to be done for every takeoff in order to show compliance with takeoff performance regulations. Basically, transport category airplanes must be able to safely accelerate to the engine failure speed and then continue the takeoff with one-engine-inoperative, or reject a takeoff with the first action to stop the airplane taken at V1 and be able to stop the airplane within the available accelerate-stop distance. The airplane must also meet certain minimum climb requirements and be able to clear all obstacles under the takeoff path. For #1, the calculations may either be done by the pilots using an EFB, or by a dispatch office using either an EFB or desktop computer.

Why all the secrecy?

It was a bug introduced by one of the recent updates. Should be fixed soon.

Just to be clear, the only reason there is any reference to the flight model is that the airplane's empty weight, fuel, passenger, and cargo loading is contained within the MSFS flight_model.cfg file. There is no change to the actual airplane's flight model, i.e. how the airplane flies in MSFS.

I use it all the time for airborne starts (for testing). I don't set the departure or arrival at an airport, I just click a spot on the map and select it for departure, then click another spot and set it for arrival.

If you set both a departure and an arrival, there will be a "NAV LOG" clickspot in the map view. You can go into the nav log to set your cruise altitude, which will also be your starting in air altitude.

At least on the 737NG, there's a "DATA" map switch on the glare shield panel that does the same thing.

😅 (Actual quote: "We have one of our really talented guys working on the flight model..."