Thrust vector-more.

[x_jasper]

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.

[PisTon]

Cool, nice find!

[cleobis]

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

[Katahu]

Are you saying that FSX has viable thrust-vectoring capabilities or are you just saying that it could be possible in FSX?

[cleobis]

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

[x_jasper]

Kat, Cleobis & Co

Nice to see your interest in this.

In Gmax, it seems, it is possible to 'set' the thrust-line at some particular angle. I have a cessna which proves this. The prop is pointing up +3 Deg.

This therefore is a 'pre-settable' feature in Gmax. So, if this thrust angle can be specified at a desired value during the build, it should be a simple matter to program the thrust angle as a variable, just as you would do with flaps, spoilers etc.

As long as the thrust-line was 'animated', actual angles etc could be accessed as usual in the config and airfiles.

Remember, FS do not recognise an engine as an engine, it only simulates thrust from a specified point in the model and in a specified direction.

Therefore since FS can support four engines, to model a Harrier there would be four thrust points. All someone needs to do is animate them. May not even need a separate module.

Someone have a go?

P.S. Not a lot of people realise this: the forward nozzles on a Harrier are 'cold' i.e. they work by thrust of compressed air from a compressor stage bleed-off. This is why they are so damn loud.

Regards

Jasper

[cleobis]

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

[SkyNoz]

I think the only problem with this idea is, you can't come up with a animation tag for the prop to pitch. These pramaters would need multiple tags, including, props, and your vectored thrust tag. This option may possibally be in FSX, but no one will know including you!

[x_jasper]

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

[Katahu]

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

Oh, I get it. So instead of directing the thrust via nozzels, you think that the thrust in FSX could be directed by simply tilting the engine itself?

[cleobis]

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...

[Katahu]

It's very likely considering that FSX now allows for negative flap dynamics.

[Daube]

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

[PisTon]

Interesting
Does that plane work in fs9, or only fsX? If only fsX, yay thanks for adding it  ;D

[x_jasper]

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