Flight Question Dll Vessel fly true

[TMHLIVE]

I was wondering if there is a easy fix to these issues.

When any thrust is applied the ship wants to pull up. When speed is reached and at altitude it seems to be better.

for example

If I hover up to 1000 and then punch it. the ship wants to pull up. I have tried the elevator. It seems the only way to keep true is to be nose down about 10 degrees and even then it is still wanting to climb.

This ship is DLL based so I can't go into any .cfg file to fix it.

Also

when the ship reaches a certain speed a big fireball starts coming from the center of the ship. It grows with speed.

the higher it goes, no fireball in the sky.

is there a way to fix that as well or shut that off in some way within a config in orbiter it self.

Thanks in advance.

 

[Hielor]

I take it the engines are near the bottom of the ship--or at least below the center?

Welcome to what happens when science fiction vessels, which are typically designed to look cool, are given real physics in Orbiter.

The only way to fix this would be to talk to the person who made the addon and get him to adjust things in the module.

 

[dbeachy1]

If the vessel has elevator trim you can try adjusting that to level out the nose-up push.

As for the fireball, that is normal at high velocities in the lower atmosphere. If you want to disable that visual effect, go to the 'Visual effects' tab in the Orbiter launchpad and uncheck "Reentry flames".

 

[TMHLIVE]

I take it the engines are near the bottom of the ship--or at least below the center?

Welcome to what happens when science fiction vessels, which are typically designed to look cool, are given real physics in Orbiter.

The only way to fix this would be to talk to the person who made the addon and get him to adjust things in the module.

It would be that ship in my sig. yes it does have one engine under the ship. So thats why it pulls up. I See. I have trimmed my elevator with no real effect. She still wants to pull up.

 

[Hielor]

Unavoidable, basically. That's how the ship would fly IRL.

 

[Loru]

First of all, we don't know how ship is coded as no sourcecode or add-on has been released.

Exhaust flame and exhaust particle streams can be rendered independently of logical thruster position so pitching caused by thrusters can be avoided.

Also wings don't have to have pitch up effect if coded properly. Pitch moments are defined in vessel's lift function and can be set to 0 (No pitch regardless of airspeed).

 

[TMHLIVE]

First of all, we don't know how ship is coded as no sourcecode or add-on has been released.

Exhaust flame and exhaust particle streams can be rendered independently of logical thruster position so pitching caused by thrusters can be avoided.

Also wings don't have to have pitch up effect if coded properly. Pitch moments are defined in vessel's lift function and can be set to 0 (No pitch regardless of airspeed).

you mean within the DLL it self? I have no idea how it is set. I am just the pilot not the maker. I am working with the maker tho. This is a SCI FI true to show addon we are working on. That being said this thing needs to fly true at any speeds. the constant having to correct is a pain on the keyboard and hands.

 

[Loru]

I am just the pilot not the maker. I am working with the maker tho. This is a SCI FI true to show addon we are working on. That being said this thing needs to fly true at any speeds. the constant having to correct is a pain on the keyboard and hands.

So tell your coder to fix those things. Place thruster in Y=0 position and create proper airfoil function that won't induce pitch.

 

[TMHLIVE]

Ya I was just wondering how to explain it really. I know nothing about it. Thanks for the advice.

---------- Post added at 08:38 PM ---------- Previous post was at 08:28 PM ----------

And He is a busy guy I am sure so I was just seeing if I was able to help out at all being the limited kinda person I am.

 

[BruceJohnJennerLawso]

And He is a busy guy I am sure so I was just seeing if I was able to help out at all being the limited kinda person I am.

Can you at least clarify what add-on this is? If its open-source, someone else who knows how to code an Orbiter module can take a look at it for you.

 

[perseus]

Could encode the characteristics of his ship, in Spacecraft3 through an ini text file is easy to modicar using notepad and test propulsive and aerodynamic parameters before creating the dll.
I recommend you investigate this option will give considerable autonomy and easy review and experience.

 

[Loru]

Could encode the characteristics of his ship, in Spacecraft3 through an ini text file is easy to modicar using notepad and test propulsive and aerodynamic parameters before creating the dll.
I recommend you investigate this option will give considerable autonomy and easy review and experience.

As stated in other thread regarding the same problem spcacraft3's airfoil function already produces pitch momentum (and it's hardcoded into sc3 itself).

 

[TMHLIVE]

We are working on the problem right now. I told the designer what is going on. He had that the y was already set to 0. we have been playing around with it trying to get it right. I turned on the visual assist to show me the D, L etc etc. When I hit full thrust (+) the D and L both shoot up fast and the ship begins to climb.

 

[Loru]

You are concerned about vessel going up or pitching up? You have to be very specific in case of aerodynamics.

 

[TMHLIVE]

The vessel pitches up sorry your right such a difference actually. this happens when any thrust is used rather then flying true and I pitch up and I want to go up.

---------- Post added at 09:58 PM ---------- Previous post was at 09:55 PM ----------

oh. This also happens regardless up the hover engines holding my altitude, kill rotation and horizon lock are active. It just seems the ship is fighting yes to stay true but physics vs speed or something I don't know keeps her wanting to pitch up and then due to engines climb.

 

[Loru]

Ask your coder to examine lift functions of the vessel (notably CM values - CM is coefficent of momentum) and read about it in API guide and reference

 

[perseus]

Try this ini file is [ame="http://www.orbithangar.com/searchid.php?ID=5171"]Nautil[/ame], adapting to PAX377, check the flight characteristics, Everything for your dream fulfilled TMHLIVE.

 

[TMHLIVE]

ha ha ha ha. Thanks for the info. But I have no idea how to do anything you just said. But seriously tho. I will pass it on. I am wondering tho, How will this fix the problem just for my own knowledge.

 

[perseus]

ha ha ha ha. Thanks for the info. But I have no idea how to do anything you just said. But seriously tho. I will pass it on. I am wondering tho, How will this fix the problem just for my own knowledge.

fly with him, and you will understand
[ame="http://www.orbithangar.com/searchid.php?ID=5171"]Nautil[/ame]

 

[gattispilot]

The flight dynamics where lift are created are the delta glider.

// 1. vertical lift component (wings and body)

void VLiftCoeff (VESSEL *v, double aoa, double M, double Re, void *context, double *cl, double *cm, double *cd)
{
	int i;
	const int nabsc = 9;
	static const double AOA[nabsc] = {-180*RAD,-60*RAD,-30*RAD, -2*RAD, 15*RAD,20*RAD,25*RAD,60*RAD,180*RAD};
	static const double CL[nabsc]  = {       0,      0,   -0.4,      0,    0.7,     1,   0.8,     0,      0};
	static const double CM[nabsc]  = {       0,      0,  0.014, 0.0039, -0.006,-0.008,-0.010,     0,      0};
	for (i = 0; i < nabsc-1 && AOA[i+1] < aoa; i++);
	double f = (aoa-AOA[i]) / (AOA[i+1]-AOA[i]);
	*cl = CL[i] + (CL[i+1]-CL[i]) * f;  // aoa-dependent lift coefficient
	*cm = CM[i] + (CM[i+1]-CM[i]) * f;  // aoa-dependent moment coefficient
	double saoa = sin(aoa);
	double pd = 0.015 + 0.4*saoa*saoa;  // profile drag
	*cd = pd + oapiGetInducedDrag (*cl, 1.5, 0.7) + oapiGetWaveDrag (M, 0.75, 1.0, 1.1, 0.04);
	// profile drag + (lift-)induced drag + transonic/supersonic wave (compressibility) drag
}

// 2. horizontal lift component (vertical stabilisers and body)

void HLiftCoeff (VESSEL *v, double beta, double M, double Re, void *context, double *cl, double *cm, double *cd)
{
	int i;
	const int nabsc = 8;
	static const double BETA[nabsc] = {-180*RAD,-135*RAD,-90*RAD,-45*RAD,45*RAD,90*RAD,135*RAD,180*RAD};
	static const double CL[nabsc]   = {       0,    +0.3,      0,   -0.3,  +0.3,     0,   -0.3,      0};
	for (i = 0; i < nabsc-1 && BETA[i+1] < beta; i++);
	*cl = CL[i] + (CL[i+1]-CL[i]) * (beta-BETA[i]) / (BETA[i+1]-BETA[i]);
	*cm = 0.0;
	*cd = 0.015 + oapiGetInducedDrag (*cl, 1.5, 0.6) + oapiGetWaveDrag (M, 0.75, 1.0, 1.1, 0.04);
}

	th_main[0] = CreateThruster (_V(-4.6,0,-51), _V(0,0,1), MAX_MAIN_THRUST, ph_main, MAIN_ISP);
	th_main[1] = CreateThruster (_V( 4.6,0,-51), _V(0,0,1), MAX_MAIN_THRUST, ph_main, MAIN_ISP);

Thruster are set at 0 and exhaust set to match the model