On your plot of inflight forces, what are the red, blue, and green lines for? You need to step the readers through all the steps of the process.
Red = thrust, blue = drag, green = gravity. See the section titled "All together now". Or put your cursor onto the graph and look at the readings.
My first question is, has anybody other than Thrustcurve.org heard of a Quest 13mm x 55mm A3T?
Quest Aerospace do not appear to recognise it.
If it does exist and you put it into a Mosquito, it will hang out of the back about 1cm more than the 44mm long Estes A3-4T - what will that do to the rocket's stability?
The page also allows you to put a C6 into a Mosquito. If you try that in reality, the Mosquito will probably not go very far due to being seriously deformed.
(It's already deformed. The page gives it a diameter of 19mm and a mass of 2g. Estes gives it a diameter of 14mm and a mass of 3g.)
Likewise, the page allows you to put an A3 into an Alpha. Unless you add extra mass to allow for some sort of adaptor, that won't go very far either as the motor will fall out.
(The adaptor's mass does seem to be included. The page gives the Alpha a mass of 38g. Estes gives it as 23g. Even the plastic-finned Alpha III is only 34g.)
So much for all the minor nits, which the average reader won't notice and which don't really detract from the overall purpose of showing basic rocket science to a novice. This it does very well, with a nice simple explanation, interactive graphs, and links to further reading for those whose interest has been raised reading the basics here. Well done! :clap: