Welcome to the advanced section of my site

 

This section is designed to cover medium and high power (HPR) rocketry. It will cover design and construction of large rockets as well as giving you information on how to fly rockets safely.

This page will be updated as I learn more about HPR (I have only being building rockets for 3 years). I will try to share what I learn with you, both the good and the bad also the just plain ugly ;-)

Designing your New Rocket

The first thing you need to do is decide what your rocket needs to do. Will it be a scale model, a payload lofter, a sport rocket going for an altitude attempt or something else? Then decide what type of motor you are going to use. What is the maximum safe takeoff weight of your rocket? What do you want to make it out of ? Metal should never be used when constructing rockets.

When you have decided what to build and what motor to use you can start designing your rocket. If you are building a scale model you can find a suitable body tube that is the right size I find that post tubes are very cheap and strong. You can then work from there. Below are some general tips on constructing a medium or high power rocket.

Remember for every power level you go up your rocket will have to be stronger to prevent it from being ripped apart by G-forces. It is better to have a rocket that is over designed than under designed.

Rocket design software

Rocket design software can be a very useful tool for working out where the center of pressure (CP) is on your rocket or how big your parachute should be. As well as letting you build a rocket in a CAD program, you can even simulate a launch of your rocket in some programs. I have included links on the downloads page for some of the programs that I use, some are free and some are quite expensive. You pay for what you get, not to say that programs like VCP are not any good but they are not quite as good as programs like Rock Sim. I don't want to start a debate here, have a look for your self.

Glues

The only glue I use when building medium or high power rockets is epoxy resin. This is a very strong adhesive that dries fast dose not expand or shrink and is resistant to heat. Safety: always where gloves and use in a well ventilated area

The Body

Tube Body tubes for HPR have to be very strong to survive a flight as some rockets can exceed 40gs during their flight. Body tubes can be made from many things like thick cardboard, PVC plastic, fiberglass or carbon fiber. Just to list a few.

The Engine Mount

Your engine mount has to be strong enough to handle the power of the motor; you don't want the motor flying out the top of your rocket! Engine mounts should be made out of thick cardboard. The centering rings can be made out of Burch plywood or marine plywood, at least 5mm thick. About three to four rings are needed for an H powered rocket.

The Fins

Fins are a very important part of your rocket. If a fin brakes of in flight your rocket can be destroyed and you can seriously hurt someone. This said how do you make fins strong enough? Fins can be made from plastic, Burch plywood, even foam cored Kevlar, fiberglass and carbon fiber. The fins have to be mounted to the engine mount and centering rings. This will distribute the load thru the rest of the rocket. See fig 1

Nose cone

Nose cones can be made out of plastic; balsa wood as well as foam covered with fiberglass or carbon fiber then the foam can be removed with acetone. Your nose cone can be designed with a program like VCP. A large bolt should be attached to the bottom of the nose cone to secure the shock cord. Wooden nose cones can be covered with epoxy for strength and to make them easy to paint.

 

Still more to come