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P3D v4 VTOL function by Flap Setting (no gauge)

Laurapintas

Laurapintas

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portugal
Hi there,

I'm trying to setup VTOL configuration on a default propeller aircraft, as a starting point for a future project.
What I want is something like Flaps Full= VTOL and Flaps 0=horizontal flight. I believe this can be achieved if, in the aerodynamics, the aircraft is set as a Flap (which makes sense). But I would like to maintain its initial characteristics as much as possible, although I am not looking for realism.
So I noticed while "playing" with AirEd, on section 1101 of a Mooney AIR file, there is the CD_df and CL_df. I have made changes with a variety of numbers, and I noticed no effect on the aircraft. It probably is connected to another(s) definition(s) of that section that shall be changed as well.
I have been comparing this file with VTOL aircraft files but as in aerodynamics everything is connected, and AIR files are hard to decipher, any insight can be helpful regarding this matter.

Thanks
 
Any flap coefficients in the air file only have an effect if the flap is down. Was it when you tried that?
Roy
 
Also, if you notice, there is a heading in the plane's aircraft.cfg that is quite useful for what you're trying to accomplish. The heading is [Flaps.n] where n is the number indicating just which flap the information is for. Like [flaps.1] could be the ones on the inside of the wing (closest to the fuselage), [flaps.2] could be the leading edge flaps, if any, and so on.
The size of the flaps may be specified, the time needed for extension, and so on. The really important ones, in this case, are the flap size, the lift_scalar, and drag_scalar. By adjusting those, you can accomplish your desired ends.
The information on all the settings under this heading may be found here: Aircraft.cfg information . Just scan down through the page until you find the [FLAPS.N] heading. All the possible settings are shown, and what effect each setting has on the plane's flight model.

Finally, by coupling these settings with the settings under R1101 in the plane's .air file, the flap settings may be fine tuned. the sections such as FIELD 0x1101 0x5e DOUBLE 0.450000 *CL_df Lift - Flaps - +tail up, FIELD 0x1101 0xb2 DOUBLE 0.000000 *Cm_df Pitch Moment - Flaps/-neg=pitch-up, but just remember that if there is a conflict between the .air file and the aircraft.cfg, the settings in the aircraft.cfg take precedence.

I did a LOT of work on the flaps of a very popular freeware aircraft available out there (ahem...FSXBA Hornet...ahem), so I'm fairly familiar with doing all this fun stuff. I hope some of this info is of help for you...
Pat☺
 
PhantomTweak said:
Also, if you notice, there is a heading in the plane's aircraft.cfg that is quite useful for what you're trying to accomplish. The heading is [Flaps.n] where n is the number indicating just which flap the information is for. Like [flaps.1] could be the ones on the inside of the wing (closest to the fuselage), [flaps.2] could be the leading edge flaps, if any, and so on.
The size of the flaps may be specified, the time needed for extension, and so on. The really important ones, in this case, are the flap size, the lift_scalar, and drag_scalar. By adjusting those, you can accomplish your desired ends.
The information on all the settings under this heading may be found here: Aircraft.cfg information . Just scan down through the page until you find the [FLAPS.N] heading. All the possible settings are shown, and what effect each setting has on the plane's flight model.

Finally, by coupling these settings with the settings under R1101 in the plane's .air file, the flap settings may be fine tuned. the sections such as FIELD 0x1101 0x5e DOUBLE 0.450000 *CL_df Lift - Flaps - +tail up, FIELD 0x1101 0xb2 DOUBLE 0.000000 *Cm_df Pitch Moment - Flaps/-neg=pitch-up, but just remember that if there is a conflict between the .air file and the aircraft.cfg, the settings in the aircraft.cfg take precedence.

I did a LOT of work on the flaps of a very popular freeware aircraft available out there (ahem...FSXBA Hornet...ahem), so I'm fairly familiar with doing all this fun stuff. I hope some of this info is of help for you...
Pat☺
Click to expand...
Hi Pat,

Thank you so much for those tips. I have been playing a little bit with the Flaps settings, but a bit lost on the R1101. Those inputs will be of great help in fine-tuning what I pretend.
I will check the Hornet. I do like fighters!
Kudos!
 
No matter what you do with flaps, you cannot achieve VTOL without a separate lift mechanism. You can achieve STOL which implies having some forward airspeed. VTOL implies zero airspeed. The wing provides lift using an equation which includes airspeed squared. No airspeed no lift.
Also R1101 is really obsolete especially as it relates to a current aircraft.cfg. A lot of stuff that used to be in 1101 is now in the aircraft.cfg. It has been replaced by individual air file sections concerned with lift and drag and tri-axis coefficients.
Hence the statement that there can be conflicts between the air and cfg files in which the cfg always wins is misleading, there should be no conflict if the current configurations for air and cfg files are used.
Roy
 
Back in the FS2004 days, we would tweak out the flaps so that if you moved like 3 or 4 knots, your plane rose up in the air. I havent tried it in P3D (FSX) but it 'should' do the same.

A secret to it is to have the flaps take a long time (many seconds) for it to go from point A to point B.

If you have 3 points, up, down, and middle, then middle could be 'slow down mode' for approaches. Or you could assign Spoilers for slowing you down, then engage flaps for VTOL mode.

You can also use Spoilers for your VTOL and then have flaps do their regular thing. Might work better. But you want VTOL to kick in slowly, especially when you come in hot, or you shoot upwards.

I think you applied 'lift' amounts for flaps and spoiler in the AIR files to get them to work right. I think we had issues with lift in the flaps sections in the configs working right. I havent messed with a VTOL setting using flaps and spoilers in ages... I had done some freeware planes back in the day (10+ years ago? ) and used this system often.

Bill
 
If you need to do 3 knots to get airborne it is not Vertical Take Off and Landing, it is Short not Vertical. STOL.
Roy
 
Sorry, I couldn't resist to reply in this thread ;)

I've been working on this "VTOL" stuff for many years, and had many (sometimes: heated) discussion's with other designers on this subject.
IMHO, true (== zero airspeed) VTOL simply isn't possible in MSFS (9,FSX,P3D) , other then using some kind of (gauge-coded, or otherwise) trickery.
Since, MSFS/P3D simply has no notion of the concept of vertical thrust (let alone: variable thrust direction), other then in the Helicopter flightmodel.
Problem is, that you cannot mix a Helo-based flight model with the usual (longitudinal thrust) flight model.

Of course, you can try to simulate VTOL (but as said by Roy, actually: STOL) using tweaks for Spoiler/Flaps drag/lift, but that will never (again, IMHO) lead to any realistic VTOL behavior.
Simply because Spoiler/Flaps tweaks have no effect at 0 airspeed.

I have made many "gauge-coded" trickery VTOL implementations over the years.
For aircraft like Harriers, V22 Osprey, F-35B, etc. (even "flying sorcers") ; none of them are perfect.
Simply because it's too complex to re-write the entire MSFS flight model (and all possible user tweaks of it) in gauge-code.
But better then anything based on Spoiler/Flaps drag/lift tweaks.

Not sure why you explicitely say you want to solve your VTOL function using Flaps (without additional gauge-code or other non-standard flightmodel-related tweaks).
Again, that will lead to (at best: near-VTOL, and with a lot of undesirable side-effects), but not to true-VTOL.

Regards, Rob
 
Yep, taking off straight up is VTOL, and its awesome. Being able to transition to 300 or 500 knots, after taking off straight up is brilliant...

Laurapintas;
I was toying with this earlier today, thought I would post these files. Very very rough, but it works with flaps and Spoiler. I used the FA-18 Hornet copied from FSX into V4, adjusted it, renamed it, etc. It became fun after a while, but took a bit to get it to work right.

A trick I learned is to use a delay (time the flaps transition to several seconds) and then the 'hit' from high flaps lift isnt too bad. Also, if you slow down before engaging full flaps, it helps also. This is if you wish to come in nearly straight down. You also want to strengthen your landing gear for high shock when you hit, coming down. The trick also is to really keep the throttle 'just right' to maintain movement. If you stop, you fall, like Rob was saying. You have to be moving.

This will require an airplane folder, a Model folder, Panel folder, Sound folder. It works fine in P3D V4. Gets up to about 450 knots, there abouts. I didnt do a lot of testing. I was trying to make a 'flying saucer' airfile set and remembered this post. Thought I would share it. This post sparked my enthusiasm for VTOL. Getting the Hornet to lift off at 5 to 7 knots is cool. Its landing gear has lots of flex, so its cool when it rises up. Then you nose up a bit, click 'flaps up' several times, go to full throttle, and you begin climbing like a banshee. The flaps give you about 5 seconds transition from lift to full forward.

Have fun!
 

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I was having a lot of fun with this yesterday... Did some more adjustments.

Reminded me of the days back in FS2004, making blimps and flying cars and VTOL's (though they are not pure VTOL's).

Cool to see this F18 lift up and hover around the field.

I experimented with quite a bit of the settings. This new V2 version is for a different plane (saucer) but you can change and adjust this to your own test plane. You will need to make all the changes to the aircraft registry block. This is only the config and AIR file set, nothing else. This gives you an idea how a system like this works. This uses Flaps and Spoiler.

Since I was making this for a saucer, not a Jet Fighter, I reduced weight to 1,000 pounds dry, and reduced fuel burn to a crazy low amount and reduced fuel on board to very little. (The saucer would run on an electrical source, not fuel, and also it would have mass cancellation instead of thrust so it would be less in weight). So you would want to adjust things to fit your criteria of what you are doing. Lots of small tweakings.

[LANDING AND APPROACH]
I adjusted mine so that it glides in at slower speeds using bigger wings settings and also reset some high drag on the spoiler. You can slow down from high speed to about 100 knots, not need flaps till you are getting near the ground, then one notch to slow (its about 1 percent of flaps) then notch 2 of flaps when you are needing to begin dropping.

[TAKE-OFFS]
Take-off is full flaps and some throttle. At about 10 knots plus, you pop-up off the ground, not fast, just a nice lift-off. If you keep that speed, you continue rising up at about 45 degrees. If you throttle down a bit, you can hover along at that height. When you give it aileron (roll), your plane will act like a helicopter and drift over to that side you are rolling to. Its a cool effect.


fun.... :)
 

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Last edited:
Quick video of the plane this morning. I wanted to video the way it behaves.

My apologies. No sound.

 
This is the AFM set for the above video jet. You will need to assemble a folder system for it; model, panel, sound, textures. I copied out the F18 Hornet parts from FSX to make this with.
 

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Is the spacecraft moving when it leaves the ground?
If it is then the rules of aerodynamics apply.
But it is not VTOL. It is STOL.
And, this is the Flight Dynamics forum, not the SCI-FI one
Roy
 
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