Once you have a successful flight, the options below open up
and then, having checked this section's box, you can then use
the model to optimise two flight parameters for a maximum
For example, you can find the combination of rocket weight
and water that gives you the best altitude or you can find the
combination of nozzle diameter and water that gives you the
best flight time.
Once the optimisation has been completed, the results of the
best flight are put back into the input sheet and that set of
results ran again so that you get the optimisation 3D graph as
well as the usual 2D graphs that you have asked in the
2D graphs section above.
One way of running this is that you can optimise one set of
variables and then select another set and optimise for that
doing this until you have the set of results you need.
When the optimisation is run, the first thing that it does is run
the data set that you have just given it so if you change
something, it will check to see if that works and if it doesn't, it
lets you know.
Next, it decides on the ranges that it is going to use and draws
a table in your browser window that it fills randomly with
results - primarily to show you that it is still doing something
and that you have not crashed it - a sort of two-dimensional
progress display - using level of colour to indicate: parameters
that result in a failed launch; parameters that resulted in a
launch where the result was poorer than the starting result;
and, those where the result was better.
Finally, it hides that away and prints out the results for the
optimised run as well as the 3D graph that was produced.
On the final graph, your staring values are marked with a
one-pixel-wide, grey line around that cell and the best value
cell is marked with a three-pixel-wide, gold coloured line
Under the 3D graph, you will see a number of smaller versions
with different colour schemes. If you are on a smartphone or
tablet, tap that image and it will display that one instead,
otherwise, move the mouse over the smaller image to do
The colour schemes allow you to pick one that displays the
graph best for your needs - there are schemes with contrasting
colours and some with gradual changes. There is also a
greyscale scheme for printing out in monochrome.
Optimisation strategies are set out in the input form so that
you don't have to remember them but it is worth remembering
that the nozzle diameter and the rocket dry weight values are
taken from the current values and the model will then change
them if appropriate. If you want to run a nozzle optimisation
subsequently, you might want to change it back to the
potential maximum - for instance, if you use a bottle with a
22mm diameter nozzle and it selects a 9mm nozzle, and you
run nozzle optimisation again, it will not look above that 9mm
value unless you reset it to the original 22mm.