There's a demonstration of the A2A Cub lifting its tail when parked in

, starting at 8:10.Keep in mind that the Cub's flight physics are handled through the Accusim module, not through FSX. So if you turn off Accusim, you can't do this. It's a tribute to A2A's programming, not to FSX flight modeling.

Thanks Alan, just what I was looking for. Seems like AccuSim is overriding most or all of FSX flight model. I wonder how it reacts to winds on ground, e.g. if it can tip over when taxiing with wrong flight controls positions on strong winds. Also, do you know what does it happen if you try to land it crabbing ? (A tailwheel should notlike a crab landing afaik)Kudos to them however!Marco

I wonder how it reacts to winds on ground, e.g. if it can tip over when taxiing with wrong flight controls positions on strong winds. Also, do you know what does it happen if you try to land it crabbing ? (A tailwheel should notlike a crab landing afaik)

It can tip, and it'll bite you if you don't straighten out the crab. Also, each wing is handled as a separate aerodynamic surface with its own performance. If you try to induce a spin in a 90-degree crosswind by kicking the rudder into the wind and dipping the upwind wing, you'll succeed. If you kick the rudder downwind and drop the downwind wing, the wind will catch the high wing and you'll be blown into a spiral instead.The air handling and some of the ground handling has sometimes been criticized for being a bit too stable, which may be the results of some inherent limitations in FSX. But it's still a great achievement - it shows what can be accomplished when you move outside the FSX engine and "roll your own."In another arena, the Dodosim Bell 206B achieves similar results (authentic helicopter physics), again by shifting key flight functions into its own modules. Interestingly, it does this progressively - there are five levels of difficulty, starting at close to default, and as you move up the levels, more and more of the advanced performance is introduced.There's some genuine creativity to be found among a few FSX developers if you know where to look.

Edited January 7, 201214 yr by Alan_A

There's a demonstration of the A2A Cub lifting its tail when parked in

, starting at 8:10.Keep in mind that the Cub's flight physics are handled through the Accusim module, not through FSX. So if you turn off Accusim, you can't do this. It's a tribute to A2A's programming, not to FSX flight modeling.

Personally I'm not too impressed with the A2A FDE. The systems and failure modelling is perfect but the FDE itself isn't.E.g .the pitch rate of the Cub is way below the one a real Cub can achieve (the real one doesn't fly like a wet sponge), and the 'lifting tail is another good example.If the FDE has been carefully enough designed you can achieve this in FSX without the need of accusim, a special gauge etc.Another point is the yaw/roll interaction of the A2A Spitfire......there is none. They mentioned that they would fix it but AFAIK they didn't (and such a basic aerodynamic error shouldn't occur at all).

BTW, here's a video showing both the new Aerofly FS and X-Plane. A great example of one of the things you CANNOT do with the MSFS flight model...

As stated above....not true

Edited January 8, 201214 yr by bstolle

E.g .the pitch rate of the Cub is way below the one a real Cub can achieve (the real one doesn't fly like a wet sponge),

It is my understanding that all axis on the Cub were moved into their extreme positions and were replicated based upon video input. Furthermore, a significant amount of the team at A2A had Cub experience including such folks as Dudley Henriques. Perhaps however this is subjective.

and the 'lifting tail is another good example.If the FDE has been carefully enough designed you can achieve this in FSX without the need of accusim, a special gauge etc.

Completely incorrect. The technology done on this simulates the airflow from the prop onto the tail surface, which itself is a lifting body. This is simply not possible with the core SDK, and to this day from the Cub moving forward from A2A are the only aircraft which simulate this organically.

Another point is the yaw/roll interaction of the A2A Spitfire......there is none. They mentioned that they would fix it but AFAIK they didn't (and such a basic aerodynamic error shouldn't occur at all).

I am not familiar with what you are referring to. The Spitfire roll rate was precisely timed based upon documentation and personal experience with these planes. The Spitfire was designed to fly essentially feet off rudder, hence why there is a foot rest. There should be little if any rudder input required for the Spitfire during a roll. This is realistic and common to how the aircraft behaved.What you do not realize is that developing a FDE in Flight Simulator is a balancing act. You can tune an aircraft to specific parameters based upon local knowledge and find that said aircraft are not able to perform well in a stall. You fix your stall, and you find that your stall AOA performance is now borked. Everything in the FDE comes down to fine tuning, experience and time... lots and lots of time mixed with testing. It is what it is, but remind yourself that many things in FSX in regards to flight dynamics are left wanting.... but it seems every simulator has it's limits. A good example of this breakdown in FSX is during a knife edge. Since the rudder in FSX is based upon yaw and not the aerodynamic properties of such, a knife edge cannot be sustained unless the "yawing" overcomes the gravity, which can be quite incorrect to produce. A good example.... take your favorite aerobatic aircraft in FSX. Throw it into a knife edge and utilize the rudder to act as an elevator and try to maintain altitude. It simply is not possible. I only know of one aircraft that can fly a sustained knife edge, and it does it by breaking other areas and doing a bit of smoke and mirrors to give the effect.Heck, the discussion of the slip turn coordinator could be a whole topic on it's own.

Thanks for an interesting post Jaggy. This again shows that there are a lot assumptions being madearound the flightmodel in each camp and even within the same camp. Each sim has it's quirks that we all as designershave to live and deal with. Our task as designers is to provide the end user with the best flight experience that the out-of-the boxflightmodel can't.It's not a question of what each SIM can do or cannot do, it's a question of what each DESIGNER/TEAM is capable of.The FS designers have been forced to "hack" the FS flightmodel for a decade, in XP many designers still believe thatif you just enter real data you'll get a perfect result. This is obviously not true, and thats something all XP designers have to admit.One day it will, but we are not there - YET!XP will give you at best a "plausible" result if you just enter real data. Reverse engineering is the only way to get beyond this,and ultimately plugins for extreme accuracy.PERSONALLY, I'm however convinced that XP has an edge in user experience inside the "normal" subsonic flight envelopedue to it's non-linear approach (smoothness and feel) and weather-dynamics model. FS on the other hand is betterat "extreme" aircraft (aerobatics etc) since the aerodynamic approach here just gets to chaotic and therefore incomplete and a look-up strategywill work better.M

Edited January 8, 201214 yr by MortenM

1. Completely incorrect. The technology done on this simulates the airflow from the prop onto the tail surface, which itself is a lifting body. This is simply not possible with the core SDK, and to this day from the Cub moving forward from A2A are the only aircraft which simulate this organically.2. I am not familiar with what you are referring to. The Spitfire roll rate was precisely timed based upon documentation and personal experience with these planes. The Spitfire was designed to fly essentially feet off rudder, hence why there is a foot rest. There should be little if any rudder input required for the Spitfire during a roll. This is realistic and common to how the aircraft behaved.3. What you do not realize is that developing a FDE in Flight Simulator is a balancing act.

1. Sorry, but you apparently don't know what you are talking about. There are a few planes in FSX which correctly simulate the prop wash over the tail and hence allow a 'brake stand' just with the standard SDK.2. There's even a thread about that problem at the A2A forum. On the Spitfire, rudder deflection and hence yaw cause a considerable roll (of course)...but only with the real Spitfire.3. ? I don't realize that ? How many FDEs have you built to make such a statementI don't know why you are trying to defend A2A that much. They are really very good but even they can make errors.

Edited January 8, 201214 yr by bstolle

Another point is the yaw/roll interaction of the A2A Spitfire......there is none. They mentioned that they would fix it but AFAIK they didn't (and such a basic aerodynamic error shouldn't occur at all).

I am not familiar with what you are referring to. The Spitfire roll rate was precisely timed based upon documentation and personal experience with these planes. The Spitfire was designed to fly essentially feet off rudder, hence why there is a foot rest. There should be little if any rudder input required for the Spitfire during a roll. This is realistic and common to how the aircraft behaved.

I'll assume we're looking at to different points here. Low adverse yaw with aileron inputs for turns, which let's you keep your feet on the floor..............versus some roll tendency when using rudder, that's caused by the Spit's wing dihedral.Since I've done extensive & head splitting reading on the subject this morning, I see that the original Spit had frise ailerons (like my un-named airplane), which will reduce the yaw , & require less rudder.........as Jaggy Films mentions.And I believe Bernt is questioning the roll (or lack of), when rudder is applied, considering the wing has 6 degrees of dihedral, which usually causes some roll with rudder use. To answer that question, I haven't yet been able to find the answers, after quite a bit of reading on the subject.I also saw, that later versions of the Spit, went with piano hinge ailerons.L.Adamson

1. Sorry, but you apparently don't know what you are talking about. There are a few planes in FSX which correctly simulate the prop wash over the tail and hence allow a 'brake stand' just with the standard SDK.

Name them, because I am completely unaware of them. The ONLY other company that I am aware of that simulates propwash and allows brake stands is the Flight Replicas Super Cub package, which is done through clever gauge coding (not the same as A2A) and cannot be controlled. The A2A model(s) can control the angle via elevator based upon power input while keeping perfectly still on the brakes. Nobody else has done this. I KNOW how this was done, and the only other company that comes close to this is VRS in their design of the FBW system on their Superbug (another person I have worked for and know very well as a family friend). He however is not modelling props, and I dare you to find another person out there who developed a FBW system like his in the simulation world.

2. There's even a thread about that problem at the A2A forum. On the Spitfire, rudder deflection and hence yaw cause a considerable roll (of course)...but only with the real Spitfire.

And it has been answered and addressed by none other than Dudley Henriques, a man who has flown over 70 air frames including the Spitfire and was a P-51 instructor pilot. The issue was addressed to my knowledge as best as possibly done. You're beating a dead horse because "you" think you can do better. You certainly were not using this tone of voice on A2A's forum, so I find it disingenuous to do so here. I think the better question is who are you and what is your agenda? Come to find out you work for a competing flight development company that is known to have VERY bad blood with A2A. That puts a lot of things in perspective to me.

3. ? I don't realize that ? How many FDEs have you built to make such a statement

I have been working in this industry for years and have worked with most every major the developer in it. A list of my resume is not necessary, you can look it up yourself on my website if you wish. I have even worked on content that your company provided at one point or another. I do however find it interesting you pull out this spade against me, but not against people who have more experience than you in the same regard.

I don't know why you are trying to defend A2A that much. They are really very good but even they can make errors.

Errors? Or limitations? Again, you have an agenda to fill. You are NOT a bystander in this conversation. Perhaps I should point out flaws in FDEs that you have designed, or that pilots who have flown said aircraft have found and pointed out to me? No, that would be unprofessional. With that said, I made my point and I feel no need to discuss it further. You can stew in your answers and I doubt you'll answer my questions.[EDIT: I find it wholly unprofessional to speak disparagingly openly about another developer, especially considering the undulating circumstances between said companies. My apologies for getting heated folks, but I am tired of this sort of thing in this profession. There are too many people who feel they must put down other's work to "prove" their abilities. I say HOGWASH!]

1. I am completely unaware of them.2. A list of my resume is not necessary, you can look it up yourself on my website if you wish.3. With that said, I made my point and I feel no need to discuss it further. You can stew in your answers.

1. well, unaware and uniformed, not my problem2. Haven't found a single FDE on your website.3. I have absolutely no idea where that weird agressiveness comes from and I really don't care. You are way off topic with your crude reply anyway.Have a nice day :(

Edited January 8, 201214 yr by bstolle

And it has been answered and addressed by none other than Dudley Henriques, a man who has flown over 70 air frames including the Spitfire and was a P-51 instructor pilot. The issue was addressed to my knowledge as best as possibly done. You're beating a dead horse because

Beating a dead horse? Here's Dudelys replyYou are correct that the rudder behavior on the Spit needs to be tweaked a bit. This has been addressed and the tweaked behavior will show as a change in the FM in a forthcoming patch.Dudley HenriquesThat doesn't look 'dead' to me :(

I find it wholly unprofessional to speak disparagingly openly about another developer.

Huh? I'm not allowed to correct this statement?

Keep in mind that the Cub's flight physics are handled through the Accusim module, not through FSX. So if you turn off Accusim, you can't do this. It's a tribute to A2A's programming, not to FSX flight modeling.

It was simply a reply that this is not the case as it is possible with the standard SDK. That's definitely no reason to get heated

Edited January 8, 201214 yr by bstolle

hmmm Jaggy touched a couple raw nerves there.

It was simply a reply that this is not the case as it is possible with the standard SDK.

Thanks, Bernt - I appreciate the correction. Good to know your take that this can in fact be done purely within the confines of FSX.A question for you - speaking as someone who's neither a pilot nor a creator of flight dynamics, and therefore needs to be reliant on people like yourself and other FDE authors for guidance: what FSX aircraft not developed by you do you think flies well? I'm not trying to be confrontational or critical - I'm genuinely interested to hear what you think meets the highest standard. Anything by Rob Young? Anything by Alexander Metzger? Or maybe something by someone I've never heard of. Just trying to learn how you see things.I've enjoyed your Carenado fixes and your work for Flight Replicas - thanks for all that.Looking forward to hearing your point of view.

Hi Alan,You don't even need to go the 'commercial' road for really great FDEs.Fischers Bücker 131 is a great add-on but you have to use the optional FDEs from flightsim.com. They are that good that a certain payware company simply used a 100% copy for their own aerobatic aircraft...One of the best available aerobatic planes is as well freeware, the Zivko Edge540.The definition of highest standard is difficult because sometimes you do have to make a compromise and it's ones personal POV of what is important.For more detailed info I send you a PM shortly.

Thanks, Bernt - very interesting. I'll check out both of those options and will look forward to your PM.