Finding the optimum delay in OpenRocket

Is there an easier way of finding the optimum delay in OR without painstakingly changing the delay times for given motor over and over again until you find the one that deploys the parachute at the lowest velocity?

There is an analytical solution. Originally, it was published by Estes Industries Technical Report TR-10, "Model Rocket Altitude Prediction Charts including Aerodynamic Drag" by Douglas Malewicki. You can also find the formula on the following website:


https://www.rocketmime.com/rockets/rckt_eqn.html

Actually, a simpler way in RocSim, and I assume it works in OR, is to use a very long time delay and see how long the model takes to reach peak altitude.

Download the new version (13.05). There is an optimum delay column labeled "Time to Apogee" in the simulation tab. Four rockets were launched today with CTI delay grains drilled to this value. All were within acceptable error range.

Edit: You can also look at the graph of the simulation. Apogee is marked. Follow the line down to the time on the x-axis.

dcbertelsen said:

Edit: You can also look at the graph of the simulation. Apogee is marked. Follow the line down to the time on the x-axis.

Click to expand...

View attachment 142550

Just take the time from burnout to apogee, and that will be your optimum delay. Make sure you get the launch angle, wind, etc. input as well, or it won't be quite as accurate.

See this thread:

https://www.rocketryforum.com/showthread.php?53388-OpenRocket-Optimal-Delay

Greg

cerving said:

Just take the time from burnout to apogee, and that will be your optimum delay. Make sure you get the launch angle, wind, etc. input as well, or it won't be quite as accurate.

Click to expand...

GregGleason said:

See this thread:

https://www.rocketryforum.com/showthread.php?53388-OpenRocket-Optimal-Delay

Greg

Click to expand...

Thanks! This way will save me a lot of time! (I have to sim 4 to 5 motors in 4 different rockets... 16 to 20 simulations in total!)