Sorry in advance for the large quantity of code. I have gone over this line by line, and can't find the issue. I'm not sure if it is in the formulae, or in the code.

This is the issue. This program takes a large variety of variables, from frontal area of the rocket, wind resistance, thrust, burn time, gravity, etc, into account. It performs the calculations, and predicts total altitude of the rocket. Fine, great. The problem is, I get garbage altitude. Like a 1-oz model rocket with a 100-Ns thrust motor.... which is bigger than the rocket, and weighs POUNDS, not ounces. This rocket should almost land on the moon. Total altitude: -44 feet. So I've tried everything I can think of, and am now coming for help. Sorry for the large chunks of code, with few comments, but I will explain anything if asked.

Again I apologize for the mass of code, but I can't FIND a problem with the coding or formula.Code:`#include <iostream>`

#include <math.h>

using namespace::std;

float velocity_squared(float velocity);

float r_squared (float r);

float root_q (float thrust, float Mass, float g, float coef_k );

float get_l_value(float Mass, float g, float coef_k, float v_s, float thrust);

float get_l_2(float Mass, float g, float coef_k, float v_s);

const float pi = 3.14;

const float Cd = 0.75;

const float e = 2.71828182845904523536;

const float rho = 1.2;

const float g = 9.8;

float l_value; /* this is the value that is used for the equation yc = [+M / (2*coef_k)]*ln([M*g + k*v^2] / [M*g]);

l_value =(M*g + k*v^2) / M*g)*/

float l_val_2;

float velocity; //v, in the equation

float v_s; //v^2;

float area;

float diam_inch;

float r; //radius

float r_s; //radius squared, used for pi*r^2;

float Mass; //in kilograms;

float boost_alt; //altitude at motor burnout

float coast_alt;//altitude gained while coasting;

float total_alt; //boost_alt + coast_alt;

float coef_k; //wind resistance temporary holder;

float impulse;

float thrust;

float burn_time;

float q;

float x;

float x_neg;

float m_neg;

int main()

{

cout<<"Enter the mass of the rocket in ounces: \n";

cin>>Mass;

Mass = Mass /16 / 2.2; //conversion to Kg from ounces

system("CLS");

cout<<"Enter the diameter of the rocket, in inches: \n";

cin>> diam_inch;

system("CLS");

r = diam_inch / 2; //useless now

r_squared(r); //ignore this whole function, it is no longer used

area = pi* (0.5*(diam_inch / 12) * 0.3048) * (0.5*(diam_inch / 12) * 0.3048);

//area in square meters;

coef_k = 0.5 * rho *Cd * area; /*temporary holding variable to implement wind resistance in other equations*/

cout<<"Enter the Impulse for the motor: \n";

cin>>impulse;

system("CLS");

cout<<"Enter the Thrust for the motor: \n";

cin>>thrust;

system("CLS");

burn_time = impulse / thrust;

q = root_q(thrust, Mass, g, coef_k);

x = 2*coef_k*q/Mass;

x_neg = x * -1;

velocity = q*(1-pow(e,x_neg*burn_time) / (1+pow(e,x_neg*burn_time)));

m_neg = Mass * -1;

v_s = velocity_squared(velocity);

l_value = get_l_value(Mass, g, coef_k, v_s, thrust);

boost_alt = (m_neg / (2*coef_k)) * log(l_value);

l_val_2 = get_l_2(Mass, g, coef_k, v_s);

coast_alt = (Mass / (2*coef_k)* log(l_val_2));

total_alt = boost_alt + coast_alt;

cout<<"Frontal Area of Rocket is " << area <<"square meters. \n";

cout<<"Total altitude: " << total_alt << "feet. \n";

system("PAUSE");

if (total_alt < 0)

{

cout<<"Try putting the motor in the other way. \n"; /*prompted by the consistent negative altitudes.*/

system("PAUSE");

}

return 0;

}

float velocity_squared(float velocity)

{

v_s = velocity*velocity;

return v_s;

}

float r_squared(float r)

{

r_s = r * r;

return r_s;

}

float root_q (float thrust, float Mass, float g, float coef_k)

{

q = ((thrust - Mass * g )/coef_k);

q = sqrt(q);

return q;

}

float get_l_value(float Mass, float g, float coef_k, float v_s, float thrust)

{

l_value =(thrust - Mass*g + coef_k*v_s) / (Mass*g);

return l_value;

}

float get_l_2(float Mass, float g, float coef_k, float v_s)

{

l_val_2 = (Mass * g + coef_k * v_s) / (Mass * g);

return l_val_2;

}

Anyone have any suggestions that might effectively point the motor the right way, at least in simulation? :P