Estes Industries
Estes Industries is a company based in Penrose, Colorado, USA that designs and builds model rocket and model aircraft engines and kits. Powered by compressed black powder capsules, the rockets can achieve altitudes of 2500 feet.
Estes Industries was founded by Vernon Estes in 1958, after he created the MABLE. The MABLE was a machine designed to inexpensively manufacture model rocket engines for the then Model Missile company.
Today, in addition to producing model rocket engines, Estes offers model rocket kits for various skill levels of modelers.
Estes Model Rocket Kits
Estes Rocket Engine Color Coding
Estes engines are color-coded for recommended use. GREEN engines are for use in single stage models; PURPLE engines for the top stages of multi-stage rockets and very light single stage rockets; RED engines for all booster and intermediate states of multi-stage models. BLUE are “plugged” and are used for rocket powered racers and radio controlled gliders, they contain no delay or ejection charge.
Estes number coding
Each rocket has a code printed upon the outer jacket. A typical coding might be A8-3.
The capital letter (A) indicates total impulse produced by the engine. Each succeeding letter has twice the impulse as the previous letter. (Example: "B" engines have twice the impulse of "A" engines). Estes produces 1/4 A, 1/2 A, A, B, C, D, and E engines. Other model rocket companies produce F and G engines. A single C engine can produce 10 newton-seconds of impulse, a G engine 160 newton-seconds.
The first number (8) shows that engine's average thrust in newtons or the average push exerted by the engine.
The second number (3) indicates the delay between the thrust and the ejection charge. This rocket has a delay of three seconds. Engines with a delay of zero are used as booster engines, where the ejection charge ignites the next engine.
Estes engine construction
The engines are constructed within a sturdy cardboard tube. Inside are placed a ceramic nozzle, solid propellant, delay charge, ejection charge, and a clay retainer cap, respectively.
The solid propellant is ignited by a coated wire inserted through the nozzle and in contact with the propellant. An electric current heats the wire and detonates the solid propellant. An engine can also be ignited by the ejection charge of a booster engine.