FSX
Hi All, (sorry, long post if you care to read it)
First, a short introduction. Which might explain why I start this thread.
For those of you who don't know me (Rob Barendregt) and what I do:
I am a FS9/X developper of all kinds of freeware, mainly "control gauges" type-of-stuff.
With the accent on anything that has to with V(S)TOL, VTOL, STOVL or any abbreviation you like to use.
Spending, on average, about 2-3 hours each day on development and support on these addons, for the past 10 years.
Be it for seperate freeware addon's to other (default, freeware or payware) aircraft, or part of a (freeware or payware) aircraft
from another designer / design team.
And since 4 years, I chose to ask no financial compensation for any of my effort when I contribute to payware aircraft.
WHY I do this for free, isn't relevant; call it "love for the hobby" , the "technical challenge", or whatever.
But it makes me independant in doing what I like most (implementation), because I don't have any commercial/financial interrest
whatsoever in any of these aircraft addons, or any flightsim business.
That said:
(For simplicity: I'll use the abbr. "VTOL" from now on).
The reason I write this post:
Lately, I've seen several simmers in this (and other forums) argue that "he/she finds every VTOL implementation made for FSX not
more then a gimmick", or words to that effect. With terms like "robotic", "not-realistic", etc etc.
I've made dozens by now, for almost any real of imaginary aircraft (other then helicopters), that I know of made as FS9/X addon.
Either on my own initiative, or when being asked by another designer or flightsimmer.
Starting with the old FS9 IRIS and FS9 UKMIL Harriers, and lately as part of Wilco's (Bazzar's) Harrier and Tiltrotor, Dino's F35B
and the SSW Harrier.
So, I obviously feel addressed by such comments
As a sidenote, to avoid any confusion:
- Razbam and Justflight decided to make their own VTOL implementation for their Harrier addon's.
I can't (and won't) comment on them, since I don't have these addon's. I can only comment/explain MY approach to VTOL.
- My VTOL implementation in the freeware UKMIL Harrier (summer 2011) is a very old one, which (to date) I find under-par myself.
Although I offered my help to bring it up to my latest "standards", UKMIL decided not to wait with their release untill I had the
time for this (sorry, even MY time for FS-design is limited). No problem for me.
A second sidenote:
The above might sound pedantic; as if I would be the only person in the world capable of implementing this "impossible" VTOL in
FSX.
- Am I ? No, certainly not.
- Will someone come with better solutions ? No doubt.
- Is my solution perfect ? No.
- Do I feel my latest implementations are "believable" ? Yes, I do. I'll explain further on, why.
Only very few designers (all having my respect) have the guts to address the "impossible" VTOL problem; I'm just one of them, and
feel the need to give MY opinion.
And as a third sidenote:
My post is about VTOL functionality only; NOT about the overall quality of available VTOL-capable addon aircraft, including
Harriers.
Because, what "quality" is, is very subjective.
Comparing various (e.g. Harrier) addons, is pointless unless you state how you weigh the various factors on what YOU feel are
important in an addon. Which is personal preferance.
See my post #7 in the recent thread subjected "VTOL HARRIERS".
As an example (I know I'm on very thin ice here, and it's very dangerous to make generalisations): if someone would ask me to make a
comparison between the two lastest Harrier products available now, based on public available info and (biassed) opinions, and in
positive-only terms:
- Razbam Harrier: great visual model and VC.
- SSW Harrier: great systems/flight modelling and multi-player capabilities.
Which proves my point about perceived "quality" and "best", I hope
Now, back to the "gimmick", "robotic" and "not-realistic" qualifications.
Reading such statements, I challenge anyone to describe why you feel that.
Of course, based on anything with MY implementation of VTOL in it.
In fact, I would welcome the critique, because it helps improving what I design, and give back to the FS community.
But before you react:
1. Make sure you've got your facts straight.
Comments like "it doesn't *feel* like a hovering Harrier" are meaningless and useless. Be specific.
Although I'm an arm-chair pilot in military aircraft, I've read/watched many Internet documents, pictures or movies I could get my
hands on, as far as VTOL is concerned.
2. My VTOL stuff is a continous development, which (I hope) gets better and more realistic in time.
So refering to an 5-year old version is pointless.
3. Please read, and try to understand, my explanation on VTOL implementations in FSX, below.
Because there is a very grey and wide area between a "gimmick" and "fully realistic behaviour"; the bounderies of which are
mostly determined by one's expectations.
(DISCLAIMER: I'm NOT talking about Helicopter models here).
So, a bit more in-depth on VTOL.
There's only ONE fact; the rest is my opinion:
MS-FS (FS-0 upto FSX-Accelleration) doesn't know the concept of anything other than longitudinal (== backward) thrust for
jet-engines. Period.
Meaning that anyone (including me) claiming to have found a way to tweak/configure the FSX FDE (FlightDynamicsEngine) in a way it
changes thrust direction (vectored thrust), is wrong.
One can influence this FDE (in .air files and aircraft.cfg files) by things like exceptional airodynamic lift and drag, using dummy
engines, or whatever, to realise VTOL; but that's it.
IMHO, and untill proven otherwise, the only way to emulate anything other then longitudinal thrust, is to "fool" FSX.
Example: with some programming tricks, you can instruct an aircraft to go straight up or down, so it LOOKS like vertical thrust.
Now, FSX doesn't allow you to implement your own FDE; the best one can do is to configure the FSX FDE (which has a hudge set of
parameters), but that is limited by what the designers of FSX have anticipated; IMHO, that won't allow one to create any believable VTOL
functionality without some hugh (to me: unacceptable) limitations and side-effects.
Like the famous "Superflaps" solution.
And since you cannot "replace" the basic FDE in FSX, the only way is to "override" the FSX FDE-calculated flight behaviour.
But even that has it's limitations, because FSX tries to "fight" that.
How I do it in my implementations: based on actual flight state and controller inputs, I re-calculate (in gauge code) parameters
for things like longitudinal/lateral/vertical speed, pitch/bank attitude, altitude, etc.. and override the FSX-calculated values
with my calculated parameters.
Sounds simple, but it isn't.
Because, in effect, it's writing new flight physics in gauge code. And is limited by what one programs and how FSX reacts on it.
Since my time is limited, I focus on normal flight procedures.
An example on this for a Harrier:
If you try to fly "inverted" with nozzles vertical, full throttle and low airspeed, my guess is that a real Harrier will go into an
uncontrollable and unrecoverable crash; allthough in my latest implementations I try to implement some logic for it, it's nowhere
near what would happen IRL. Because it's guessing, solong as nobody has video footage of such a maneuver; or is a real Harrier pilot.
I've come to the conclusion it's not worth the effort; in future implementations, in such a situation, I'll just switch off my
control and let the FSX FDE decide how to crash it
- If you call that "not-realistic": so be it; I fact, I agree.
- Is that aspect of the simulation important ? Not to me; but that's my opinion, and have yours.
Another thing I want to address:
It may sound funny, but implementing VTOL for a Harrier is far more complex then e.g. for a FBW aircraft like a F35B.
Based on how I do it, somelike like "hovering" a F35B, is far more easy to emulate, since the FBW automation prevents wrong pilot
actions
Main restriction here, is lack of proper documentation on how a real F35B pilot actually controls the aircraft; pictures and
you-tube video's explain a lot, but only the most common controls and behaviour; the rest is based on educated-guessing.
And another one: the issue of "transition" effects.
As explained, my VTOL solution is based on overriding FSX-calculated parameters; meaning that there are "transition" effects when
these controls are switched On and Off. Because FSX doesn't "like" that.
The art is to make them as un-noticeable as possible.
But if you know where to look, you 'll be able to spot that in my VTOL implementations; as I'm convinced, you'll find that in any other
implementation that simulates VTOL.
Last examples (from the SSW Harrier):
1. Emulation of the pilot using the STO-lever, and simulation of the ability to "lift" it over the VTO-stop and set STO-stop.
2. Calculated Max. VTOL-weight, dependant a.o. Altitude and water-inject derived from (I admit) simplified real-world data.
3. Emulation of Ground effect in a hover.
Are these important features ?
To me, as a designer and simmer, they are. Much more important then a perfect visual nose, or 20 liveries.
Because VTOL is what makes a Harrier such a unique aircraft; so such details are important.
But again, that's only MY opinion; your's may differ.
Hope the above gives you some insight.
Again, I can only comment on how I do it, and what I implement in various addons.
If you STILL feel VTOL in FSX is just a "gimmick": I have no problem with that. You are entitled to your opinion
BUT: be fair then, and explain what you miss or what, in your opinion, is not realistic.
And as long as you realise that "Realistic" is only determined by what your (my) standards are, and what you (I) feel is important in a
simulation.
Best regards, Rob Barendregt
PS:
I'm Dutch, English is not my native language.
So if anything I write strikes you as odd, or maybe even offensive: that is certainly not my intention.
I just don't master all the fine nuances of the English language.
But I'll gladly communicate in Dutch if you prefer ...
Originally Posted by rcbarend
Thanks and to all developers building these brilliant models , the Wilco is my first flight sim VTOL fix wing aircraft model and got this one duly to the detail but course having technical books on the shelf makes it extra interesting and following the history , I put Helicopters into a different category as rotor wing but all first time RAF Harrier pilots were rotor trained ,so I approach all newly brought FS aircraft as a test pilot - both go hand in hand , i then pull out the books and away i go . 
)
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