Hi all

There was a recent thread on thrust vectoring, but out-lived it's usefulness.

A number of people had said they would have liked to see true thrust vectoring in FSX, and not the customary 'helo type' effect normally used.

I was mucking around with one of the stock single engine props (ex-FS9) in FSX the other night and modelled the dynamics with wing and stabiliser directly on the prop thrust line. �Airfoil section was a modified symetrical arranged to have minimal lift change vs airspeed.

What I found was that this particular model would pitch-up in relation to power setting, e.g. thrust.

A cure was found by simply changing horizontal stabilizer pitch to compensate.

However, I examined the graphic model and discovered that the prop itself was pitched up, by some 3 or so degrees.

I could only summise that this indeed was the reason for pitch-up vs thrust, and that this is a feature solely related to how the model was created in the first place.

From this I am now thinking that it would be a very simple matter to 'animate' the thust line, in a similar way to how flaps, control surfaces etc are arranged as animations during the model build.

This, and perhaps a simple dll module could in-fact give us true thrust vectoring. e,g, why not build-in thrust direction as a variable animation?. Clearly, it's possible to specify thrust direction as a fixed quantity, all we need to do is have it movable.

Hope someone has a go at doing this.

Jasper

sadly I'm a very far of being a modeler or I would try this imidiately, I hope someone try this...

freat find jasper

so, I understand that what you are saying is to create an animation in gmax "attached" to the engine (or thrust output) as you do with flaps where FS recognizes the change of the animations as flap angle change, but woulnd't FS need to have an instructiuon built in to recognize that particular animation as being related to thrust?  or could it be possible to create a dll module that would make FS do the change?

A thing that I thought a couple of years agor was if it was possible to "attach" the engines to the flaps, I mean, make the thrust coupled with the flaps, and maybe that way FS by recognizing the flaps angle change wouild also change the thrust vector, but being no .air file master I could never find if that was possible....

hope someone gets a breakthrough regarding this...I woudl gladly pay 5 or 10 � for a module that emulates vectoring thrust in a realistic way, noit just a "mechanic" way as the gauge we have curreently...thougjh I am very thankfull for that gauge

cheers

I think is saying that it might be possible... lets hope so...

hmmm....now it all makes sence....

I like that idea...it should be fairly simple to try in gmax, even with just a box, only to see if the animation works...

sadly I only have a basic knowledge in gmax doing scenery, so I never did the a/c animations...

hmmm, these days I'm kinda busy, but if I get time I might get a go at that...

Have to read the sdk's though...very good idea jasper....hope it works...

oh, just remembered, a doubt:

this way the animation capability would have to be dependant on gmax being able to do it, and so, is gmax able to animate the thrust line?

cheers

Ok, I am suggesting that a Harrier (or plain box) be modelled in Gmax with animated nozzles. Now, could each nozzle be assigned as an engine or thrust point?

If so it should work if the thrust line will follow the animation.

Again, I actually have a Cessna which visually does have a 'crooked' prop, you can see it quite plainly. The clue is that I know for a fact (and have proved it) that the 3 deg offset prop on that model is deffinately producing a 3 deg thrust-line.

In other words, I got a 3 deg offset prop, I get 3 deg offset thrust.

Therefore, If that prop were 'animated' instead of fixed----- the problem should be solved.

Jasper

hmmm..ok...but usually those kind of animations, like the harrier, the nozzles animations are tagged to the flaps...

So, you need to creat a new tag that recognizes the thrust line change of angle, and that is whay I got the idea of connecting the engine to the flaps, but I don't know if it would be possible to get the two together...

in any case it is very good to know that FS recognizes the angled thrust as jasper says...

I'm following this topic with a lot of interest.
X-Jasper, thank you very much for your inquiries  8)

Hi all

Piston:

Yes, the cessna with the crooked prop & thrust-line works in FS9 and FSX.

Basic fact is, these two sims certainly do recognise that the thrust-line has a tangental component. My modification to the Cessna was to entirely re-write the dynamics and give it a true mid wing / zero incidence position with both flight sim and CoG reference bang-on zero, i.e. dead centre. Horizontal and vertical stabilizers were configured as a symetrical 'cross-tail' in a neutral position about the longitudinal and lateral axes.

This gives a situation where for all intents and purposes we have a model perfectly balanced about it's CoG and aerodynamic centre of lift, the ideal configuration to examine what the thrust-line is doing.

Using a special 'flight test panel' with real time power and thrust data, it was easy to see that actual thrust was responsible for significant + pitch on this model. This ocurred before any real increase in airspeed. Moreover, keeping the model on an even pitch and neutralising the effect could only be achieved by setting positive incidence on the horizontal tailplane.

All that stuff aside, visual check of the model shows that whoever built it gave it a tilted prop!

Proof that the sim really does recognise angled thrust.

I strongly suspect the reason why no one has bothered with this could be the fact that really the only serious VTOL was the Harrier. If you stop to think about it for a while it becomes obvious that for any meaningful simulation you would need at least two extra controls on your stick, i.e. a slider each for the front and rear nozzle pairs. This could be achieved by configuring a three-throttle flightstick, or having an auxillary throttle unit on a second USB port. Either way, it could be in-fact that this is the real obstacle. thrust point animation might actually be perfectly possible and dead easy.

Jasper

For FSXI, ACES I believe that ACES hav to concentrate on multiple, complicated propulsion types, including complex ones, like on VTOL aircraft.  Don't get me wrong, sort out the main physics first, but then add more propulsion types.


About the AV-8B Harrier.  There is a thrust lever, with detents for normal flight power, and Hovering power (with a cooling water supply which lasts 90 seconds during hover (otherwise the engine overheats)), and a nozzle lever, much like a flaps lever, which controls all of the nozzles at once.  The stabilization is done by 'bleeders' which have feeds from the engine thrust, where valves release rushing air which controls the aircraft during hover.  This is automated when the Harrier is hovering.

This is the information I know abot the harrier, when I once saw a documentary about it.

Quote:

Nothing wrong with that!  It was impressive to watch the Harriers in action in Iraq.  The only thing that impressed me more was the AH-1W's that flew no more that 10 feet over the tops of our tanks!  I really hope you guys get this figured out, seems like you are all almost there!

I suggest we stay out of this sucking politics stuff. 

Sounds like an Ekranoplan opportunity...

Engine 1 on the prop, 2 and 3 on the nose, kick it up with all engines, then adjust 2+3 for the needed lift and 'fly' with #1 only

Lmao!

why, on earth would you want one of those? ???

Cheered me up that has

Jasper

How many engines does the alphasim one have in the FDE. Should be 3 as it is an A-90