All Rocketry Blogs

 Rocketry Product: Estes - Doorknob {Kit} (9720) [2020-]

Model Rocket Building: Estes Doorknob, #9720 Build, Part 1, Parts (2020-05-29)

The stocky body, orange and white roll pattern set this one off! The parts were all of good quality. 3" diameter heavy slotted tubing and 18" parachute. Parts of interest: That BIG nose cone Peel ... [Read More]

Model Rocket Building: Estes Doorknob, #9720 Build, Part 2, Engine Mount (2020-05-30)

The green ring had a burr that needed smoothing. I turned it against the nose cone, but it still required some sanding to slide over the engine mount tube. This instruction picture was a little ... [Read More]

Model Rocket Building: Estes Doorknob, #9720 Build, Part 3, Fin Shaping (2020-05-31)

You can build the model as scale or sport style. On the left is the Scale fin with the diamond taper leading edge. The Sport fin has a rounded leading edge. If you extend a parallel line from the ... [Read More]

Model Rocket Building: Estes Doorknob, #9720 Build, Part 4, Fin Filling (2020-06-01)

Here's the scale fin after shaping. On the right are all four fins. Notice the black line, thin and centered down the leading edge. This is all the black that is left after shaping the scale fin. ... [Read More]