industries estes cox corp. founded denver colorado u.s. 1958 1958 founder vernon estes headquarters denver colorado products model rockets and model aircraft owner hobbico inc. website http www.estesrockets.com estes industries aka estes cox corp. is a company that was started in denver colorado usa . the company was the first to mass produce model rocket engines with consistent and reliable performance . the company soon began producing model rocket kits launch equipment and other accessories . in 1961 the company was moved to a 77 acre tract of land on the outskirts of penrose colorado . rapid growth followed and soon penrose became known as the model rocket capital of the world . in 1969 vernon estes sold the company to the damon corporation of needham hts ma . damon purchased a number of other hobby companies including a smaller competitor of estes centuri engineering of phoenix az . damon merged the two companies under the name centuri engineering . the penrose entity continued doing business as estes industries . centuri engineering model rocket products continued to be developed marketed and sold from the centuri offices in phoenix as well although the actual manufacturing of centuri products was soon moved to the estes facility in penrose co. sales of centuri model rocket products were never as successful as estes brand products and the centuri engineering offices in phoenix were finally closed and the centuri product line was discontinued in 1983 . following a hostile takeover of the damon corporation in 1989 estes industries was divested and became part of hobby products . the business name of the company was shortened to centuri corporation . in 1996 hobby products acquired the assets of cox products of corona ca . cox products was a designer and manufacturer of model airplanes and glow fuel model airplane engines and more . the company s assets were moved to the estes facility . in 2002 the combined company was sold again and the company s name was changed to estes cox corp. on january 15 2010 estes cox was again sold and became a wholly owned subsidiary of hobbico of illinois . sales of the cox line of model airplanes has been continued by hobbico . contents 1 history 2 accomplishments 2.1 mable 2.2 indoor launch of model rockets in astrodome 3 estes rockets 3.1 estes rocket engine color coding 3.2 estes number coding 3.3 estes engine construction 4 reception 5 notes 6 external links history edit estes industries was founded by vernon estes in 1958 . in 1969 vernon estes sold the company to the damon corporation . on august 30 2002 barry tunick who had been the chief executive officer since 1991 acquired estes cox corporation from the private equity fund tcw capital for the sum of 15 million . on january 15 2010 estes cox was acquired by hobbico inc. 1 accomplishments edit mable edit vern estes created mabel . 2 mabel was a machine designed to inexpensively manufacture model rocket engines for model missiles incorporated . mabel was capable of producing a completed model rocket engine every 5 1 2 seconds . the operation began with an engine casing tube being loaded onto a rotating table video reference arm seen moving up and down is picking up tubes from tube hopper . the table then advances through multiple stations where the nozzle propellant delay and ejection components are added . a paper end cap is then cut from a roll of heavy paper tape and inserted to retain the loose ejection charge . the completed engine is then ejected from the table sent through the printer and dropped into the finished engine box below . 3 indoor launch of model rockets in astrodome edit along with several smaller rockets estes sponsored an indoor launch of a model of a saturn v at halftime of the bluebonnetbowl in the houston astrodome on december 31 1969 4 5 estes rockets edit main article model rocket five rockets from estes in 1969 the alpha saturn v semi scale x ray aerobee 300 and astron ranger estes produced a wide variety of rocket model kits normally using paperboard tubing for the fuselage and balsa wood for fins and nose cones . early models tended to be relatively simple in design terms differing in terms of size number of stages and recovery method . one particularly well known design from this era was the camroc a small camera that replaced the nose cone of larger models that was designed to take a single image on a small disk of film when the motor had burned out and the rocket was facing downward . the cineroc used a small movie camera that could be launched from larger rockets taking a series of frames as the rocket ascended . later model kits from the late 1970s and early 1980s tended to be more for show than performance including a series of scale or sport scale designs and exotics . centuri was also well known for these sorts of designs and the two companies often copied design elements from the other s latest models . the downturn in the hobby in the later 1980s led to consolidation of the two companies . during the 1990s the model line was dramatically reduced and the ones that were left were typically very simple three fins and a nose cone designs that were partially or entirely completed . estes rocket engine color coding edit estes rocket motors . from left 13mm a10 0t 18mm c6 7 24mm d12 5 24mm e9 4 estes engines are color coded for recommended use . green engines are for use in single stage models . purple engines for the top stages of multistage 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 aerobrake recovery rockets and radio controlled gliders ; they contain no delay or ejection charge . black has been used in the past for static test engines which were also plugged to prevent blow through . it can be dangerous to use upper stage engines in normal single stage rockets . the large delay in ejection can be problematic . the rocket may already be halfway through its descent when the nose comes off and the rocket may not slow down enough before it hits the ground . estes number coding edit main article model rocket motor classification type 6 total impulse newton seconds a 0.31 0.62 a 0.63 1.25 a 1.26 2.50 b 2.51 5.00 c 5.01 10.00 d 10.01 20.00 e 20.01 40.00 f 40.01 80.00 each rocket engine has a code printed upon the outer jacket . this code is defined by the national association of rocketry nar . an example of one such code is a8 3 . the capital letter e.g. a indicates total impulse produced by the engine . each succeeding letter represents a power range with maximum total impulse twice the impulse of the previous letter . example a single c engine can produce anywhere from 5.01 to 10 newton seconds of impulse a g engine 80.1 to 160 newton seconds . anything over a g engine is considered high power model rocketry . the first number e.g. 8 specifies that engine s average thrust in newtons or the average push exerted by the engine . thus a b6 0 and a c6 0 will both produce the same average thrust of 6 newtons but the c6 0 having twice the total impulse will fire for twice as long . the rocket engines produce maximum thrust shortly after ignition and thrust declines to a steady state which is maintained for up to 2.5 seconds prior to burnout . 7 the final number e.g. 3 indicates the delay between the thrust and the ejection charge in seconds . engines with a delay of zero are typically used as booster engines in multi stage rockets and there is no ejection charge . in this case the burning propellant ruptures through the top and hot bits of propellant enter the nozzle of the upper stage engine thus igniting that engine and forcing the booster assembly away hopefully to tumble safely to earth . estes engine construction edit 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 . 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 ignites the solid propellant . an engine can also be ignited by the hot gases from the propellant of a booster engine . reception edit estes model rockets are popular and used by a large number of hobbyists and educators . however measurements reported by a group at the university of central arkansas found that estes rocket motor models a3 4t a8 3 b4 4 b6 4 c6 5 and d12 3 have a measured impulses from 15.4 % to 22.8 % below the claimed impulse . 8 a study at the australian defence force academy found estes d11 p motor to have an impulse 11.4 % below estes specifications and the c6 0 motor to be 4.45 % below estes specifications . 9 a third study found the a10 pt motor to have a total impulse 20 % below estes claims . 10 notes edit hobbico acquires model rocket maker estes cox champaign urbana news gazette january 2010 vern estes using mable . reference information about mable . model rocket news volume 10 no 1 february 1970 article in model rocket man pdf . estes engine chart pdf . estes model rocket engines engine time thrust curves pdf . penn kim and william v. slaton measuring model rocket engine thrust curves the physics teacher december 2010 volume 48 issue 9 pp. 591 . an investigation into the combustion and performance of small solid propellant rocket motors m.g. carter . university of new south wales at the australian defense force academy . 2008 . measuring thrust and predicting trajectory in model rocketry m. courtney and a. courtney . cornell university library . 2009 . external links edit wikimedia commons has media related to estes . estes industries retrieved from https en.wikipedia.org w index.php title estes industries & oldid 720559087 categories model rocketrymodel manufacturersrocket engine manufacturerscompanies based in coloradofremont county coloradohidden categories commons category with local link 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