Im curious to know about this idea, or actually implementation of using an external flight dynamics engine outside of FSX is really the future of development. Majestic did it with the Q400, and I believe the FSLabs is doing it with their 320. Not sure if PMDG is implementing this as well in their upcoming projects. 

 

  If so, then it would seem it kinda gives FSX some further vitality to continue on.    However there must be disadvantages to what appears to be good advantages such as not having such a burden on the system. 

Because its external, outside the box of FSX, what limitations does it overcome other than the lack of obvious hit of using the 4gb VAS? Surely its still governed by what FSX is not able to model very well. 

 

 

Be alright if it were able to use FSUIPC/Simconnect. If not. I believe its more important to give up some realism for addon functionality?

Surprisingly I was having a discussion about this with a friend yesterday about this same topic. We concluded that it has more positives (more realistic flight model)than negatives in it's implementation. However the drawbacks for instance, wind effects and turbulence on the aircraft may sway some developers from going this route. But I'm sure developers will get around that.

t'would be nice if somebody could maybe try to explain to us common souls what exactly does it mean, 'external FDE outside FSX' .....

AFAIK there's still a normal suite of aircraft.cfg, including flight_tuning, engine data, airplane_geometry, propeller, various systems, etc. plus the 'inevitable' .air file ??...

Have to say flying the Majestic Q400 has something magical about it....

Edit : ah, i see now... there's a bunch of xml files pertaining to flight dynamics... I suppose these will overwrite data in the aircraft.cfg and .air file...  ? Very ingenious !

Sorry, i understand now ( i think ), please disregard my question.

Surprisingly I was having a discussion about this with a friend yesterday about this same topic. We concluded that it has more positives (more realistic flight model)than negatives in it's implementation. However the drawbacks for instance, wind effects and turbulence on the aircraft may sway some developers from going this route. But I'm sure developers will get around that.

Is this because it doesnt communicate directly with simconnect or fsuipc?

Is that the only negatives?

A lot of the top models have already been out of fsx. Just not to the extent of the Q because it is a prop it also handles differently.

I think the Q400 is the first with a complete FM outside of FSX.   Accusim aircraft, AFAIK have mostly external systems modeling and some addon FDE effects like altered ground handling etc, but the flight modeling is essentially done within the .cfg and airfiles.   Milviz did elevator and elevator trim control for the F86 through simconnect; the rest was done within.   But I don't think the practice is widespread

 

 

But I don't think the practice is widespread

 

See thats what im wondering. It seems to be quite the novel concept, with great advantages, but why isnt it widespread. Since FSX has all these limitations and particularly FPS challenged, going with an external model seems to make  alot of sense. Yet its not really fully embraced. I havnt seen PMDG mention anything about it and they are the standard. 

I would love to see more Addons coming out with External FDE, but I believe it's too complex. The guys from Majestic have been doing Addons for more than 10 years probably, it's not something anyone can do. But it would be so cool to have Business Jets, GA, all flying without FS limitations!

My opinion-  the concept of a separate FDE outside of the FSX core will meet with the same resistance as most iterations of FS have when trying to go a new way with development., and that's the investment  we all have in legacy add-ons that don't work in a new environment. 

 

Thanks, Bruce.

 

See thats what im wondering. It seems to be quite the novel concept, with great advantages, but why isnt it widespread. Since FSX has all these limitations and particularly FPS challenged, going with an external model seems to make  alot of sense. Yet its not really fully embraced. I havnt seen PMDG mention anything about it and they are the standard. 

I believe that it is more widespread than you think it is.  If I recall correctly, AirSimmer was the First to really dive into the external control realm...and failed miserably.  VRS was the 1st successful developer when they developed a completely independent FBW system for their F-18 'Superbug.'  PMDG did it with the MD-11, etc.

I am sorry. I really didn't understand  the concept of  FDE out side of FSX. I have  Q400 , I don't see any difference or any advantages with FDE then problems with  side effects of FDE's  no Turbulence/wind effect and no Spot View . Still the same old FPS performance,.

 

When  I ask  where are the turbulence ,wind effects and Outside Spot view, only answer getting ,Oh! we are FDE out side FSX, you have to accept it. OK I will accept it, show  me where shall I look at to realize amazing Out side FSX.  .

If I don't see any advantage of FDE, may be it is good to stay in the FSX and fly well developed Q.400 with weather effects.

 

 

I am sorry. I really didn't understand  the concept of  FDE out side of FSX. I have  Q400 , I don't see any difference or any advantages with FDE then problems with  side effects of FDE's  no Turbulence/wind effect and no Spot View . Still the same old FPS performance,.

It does have its advantages, apparently the air stream coming from turboprop engines of Q400 affect also its flight properties, something that is apparently not possible to model using normal FSX FDE. Based on what I've hear that was the reason they went with external FDE and I think they did well, Q400 definitely feels way more dynamic and realistic to fly than most aircraft out there.

 

Also try stall the Q400, you should find the stall to be way more believable than with your average FSX flight dynamics using aircraft. 

I havnt seen PMDG mention anything about it and they are the standard. 

 

Here's what PMDG said about it recently on two occasions yesterday and in April when they were asked about it.

 

 

 

We *do* do things to the FDE outside the sim. Yes, it's still technically "using" the FSX FDE but we're adding a lot to it externally and doing unconventional things - this is the whole "fly-by-software" idea I mentioned in my original comments about this. The idea that some of you seem to have that we're using stock or generic FSX airfiles that are unrealistic for an airplane like the NGX or 777 is completely bogus. There's a ton of reprocessing and modification going on behind the scenes to get the desired performance and effects.

 

The main point is that there's more than one way to skin a cat here folks. What Majestic did makes sense for a free-rotating turboprop - FSX's free-rotating turboprop model is very broken in FSX and they had to do what they did to make certain things work correctly. (and before anyone asks, the J41 is a geared turboprop and we were able to make it work with the aforementioned techniques because of how those engines behave, which is quite different from the free rotating ones) We don't think this technique makes a whole lot of sense for a jet airliner in FSX. If you run into icing in a big jet in real life you're about to lose your ATP license for flying headlong into a thunderstorm or for neglecting to turn on AI. (actually I'm not sure you can even forget to do that in the 777, the airplane may turn it on automatically as soon as it detects any buildup) Icing is a problem for smaller airplanes like turboprops flying at lower altitudes - not generally for big jet airliners.

 

Also, I've tried a couple times to get the ice to overwhelm the anti-ice system in the Q400 by flying it headlong into storms and stuff - nothing happens as far as I can tell. As long as you have the AI system on it always clears the ice. In real life you can overwhelm a boot system if you fly into really severe icing. Again - this is a simulator and there's always going to be limitations to everything vs. reality. You paid $50, not $5 million.

 

 

 

 

No, we're not doing this for multiple reasons:

 

1. We already do something quite similar - the NGX is already completely "fly by software" - we intercept the joystick prior to FSX and modify the inputs behind the scenes to produce things FSX can't normally do. Remember that the guy who programmed these algorithms here is an engineer with a PhD in computational fluid dynamics - I've seen people who appear to think we're just using FSX defaults or something and nothing could be further from the truth. This guy designs these types of mathematical physics models in real life industry. Simply put, using some other FDE would be pretty redundant here, Vangelis is already doing a ton of work of his own that's similar to this. It isn't just the flight modelling either - we do almost everything on its own outside the sim - fuel, pneumatics, autobrakes, electrical etc - it's all custom. Apparently we need to highlight this a bit more in the marketing we do, because a lot of people seem to be under the assumption that we aren't doing these things when in fact we were one of the pioneers of it going all the way back to the first NG we did in 2003.

 

2. The jet modeling in FSX is not nearly as bad as the free-rotating turboprop is. We can get very very close by tweaking/massaging the FSX model into doing what we need and it'll do 99% of the envelope right on the numbers from Boeing. Edge of the envelope is extremely difficult even in multimillion dollar full motion level D sims. I've personally seen level D sims completely "spazz out" and require reloading the situation if you get it into certain edge of the envelope states that it can't process. (it just starts flipping around unrealistically like crazy, it's pretty funny actually) Separated airflow/high AoA/stall physics is not something that is easy to model at all even for the best simulations in the world. Unless you are a Boeing test pilot, stalling a 737 or 777 is absolutely the last thing you'd ever want to do in the real airplane anyway.

 

As an aside on this - I've seen some people make claims in the past week to the effect that the NGX doesn't "feel" realistic. The idea that a large swept wing jet should fly in a similar manner to a smaller and much lighter straight wing turboprop is something that doesn't make a whole lot of sense. The weight and the way the wing of a larger jet works is going to smooth out a lot of that "loose" getting-thrown-around-by-the-airmass type feeling you get in a smaller plane. You can feel this difference as a passenger even - a couple months ago I got off a 757 straight onto an ERJ-145. There's a very pronounced difference there - the 757 feels very stable and has that almost "on rails" thing going on.  It's a big airplane that's displacing a ton of air and you don't notice little bumps and gusts. The ERJ on the other hand is more like a turboprop - it's small, has a straighter wing, and you feel the airmass a lot more. We had a ton of real life pilots on the 737 test team (and even more on the 777 team), we got to fly the full flight simulators ourselves, Robert himself has an ATP and has flown large jets. etc. I don't think we're wrong about how they fly after all of that.

 

3. To do this sort of thing you have to run FSX in what amounts to slew mode where the external FDE is just positioning the plane where it wants it based on the algorithms - this breaks compatibility with a ton of addons and hardware that read information out of the FSX flight model, causes the aircraft to not respond to the FSX weather events like turbulence, and so on. We're definitely not willing to do that - we'd have a ton of complaints if we did with how big our market is.

 

4. Running more processes like this on top of what FSX is already doing is not going to improve framerates. I suspect their FPS are higher largely because their VC has a lot less clickspots, animations, draw calls and texture resolution than then NGX does, not because the flight modelling is somehow granting it a ton more frames. As well done as their simulation is, it's also a fact that a Q400 is a much simpler airplane (in real life) than a 737 or 777. Full geometric path VNAV that takes into account both altitude and speed with all manner of soft and hard constraints, variable target descent speeds and limits, autothrottle logic etc is very heavy math. (There's all kinds of calculus and differential equations involved in doing it) Look at what our LNAV is doing too - all the turn prediction curve drawing etc - those aren't static things that get drawn once, they're dynamically generated based on the current flight situation and get recalculated with every "tick" of the aircraft's system timers. Again, very heavy math that the Q400's route line drawing doesn't have to do.

 

To sum up - I do really like what Majestic's done - I've been flying it a lot since it came out, but this kind of flight model thing as it's implemented in the Q400 is not something we're going to be pursuing for all the reasons listed above.

 

Here's what PMDG said about it recently on two occasions yesterday and in April when they were asked about it.

 Thanks for the quotes. Dont recall reading that. Interesting read though. I knew they obviously had very advanced techniques. 

But the distinction of using it for turboprops and jets is well explained. Still amazing how they can figure out how to overcome FSX limitations as it is be it partial or full external engines, or whatever they need to do to keep the realism up . And that credit goes to all devs who work hard at it.