I decided to test the limits of OpenRocket by simulating a full-size Saturn V rocket in it. I wrote an article on the project for our club magazine (in Finnish).
The results were reasonably good, considering OpenRocket doesn't do full spherical coordinates and the rocket flew at over 20 Mach. In OpenRocket the design reached an altitude of 152 km, while the true orbital altitude was 191 km. (The curvature of Earth at that distance is ~300km.) The rocket's speed profile matches reality quite well, though it remains 20% too low. The acceleration is very close to reality especially during the first stage.
(Flight profile, velocity and acceleration. Dashed line simulated, solid line reality.)
Because I wanted to simulate a real flight where the rocket is actively controlled, I added a script to the simulation which forced the orientation and speed vector direction to be that of the real flight. OpenRocket was left to simulate the acceleration, speed and position of the rocket. (If you want to try this yourself, for security reasons you need to manually re-enable the script in Simulation Options --> Javascript script.)
You can find the article (in Finnish), the ORK design and necessary engine definition file at https://www.sats-saff.fi/node/106
Below are a few images from the design. I had to use a slightly modified OpenRocket version to create the images, as the default version does not expect the 3D models to be so large.
The results were reasonably good, considering OpenRocket doesn't do full spherical coordinates and the rocket flew at over 20 Mach. In OpenRocket the design reached an altitude of 152 km, while the true orbital altitude was 191 km. (The curvature of Earth at that distance is ~300km.) The rocket's speed profile matches reality quite well, though it remains 20% too low. The acceleration is very close to reality especially during the first stage.
(Flight profile, velocity and acceleration. Dashed line simulated, solid line reality.)
Because I wanted to simulate a real flight where the rocket is actively controlled, I added a script to the simulation which forced the orientation and speed vector direction to be that of the real flight. OpenRocket was left to simulate the acceleration, speed and position of the rocket. (If you want to try this yourself, for security reasons you need to manually re-enable the script in Simulation Options --> Javascript script.)
You can find the article (in Finnish), the ORK design and necessary engine definition file at https://www.sats-saff.fi/node/106
Below are a few images from the design. I had to use a slightly modified OpenRocket version to create the images, as the default version does not expect the 3D models to be so large.
