Editing Model rocket (section)

== History of model rocketry ==
While there were many small and rockets produced after years of research and experimentation, the first modern model rocket, and more importantly, the [[#Model rocket motors|model rocket motor]], was designed in 1954 by [[Orville Carlisle]], a licensed [[pyrotechnics]] expert, and his brother Robert, a [[model airplane]] enthusiast.<ref name=pyroguide>{{cite web |url=http://www.pyroguide.com/index.php?title=Black_powder_rocket |archive-url=https://web.archive.org/web/20070905045721/http://www.pyroguide.com/index.php?title=Black_powder_rocket |url-status=dead |archive-date=2007-09-05 |title=Rocket (Black Powder) |publisher=PyroGuide |date=2010-04-10 |access-date=2012-07-06 }}</ref>  They originally designed the motor and rocket for Robert to use in lectures on the principles of rocket-powered flight. But then Orville read articles written in ''[[Popular Mechanics]]'' by [[G. Harry Stine]] about the safety problems associated with young people trying to make their own rocket engines. With the launch of [[Sputnik]], many young people were trying to build their own rocket motors, often with tragic results. Some of these attempts were dramatized in the fact-based 1999 film ''[[October Sky]]''.<ref>{{cite book |last=Hickam |first=Homer H |title=Rocket Boys |publisher=[[Random House Publishers|Random House Publishers, Inc]] |year=2000 |isbn=0-385-33321-8}}</ref>  The Carlisles realized their motor design could be marketed and provide a safe outlet for a new hobby. They sent samples to Mr. Stine in January 1957. Stine, a range safety officer at [[White Sands Missile Range]], built and flew the models, and then devised a safety handbook for the activity based on his experience at the range.

The first American model rocket company was [[Model Missiles Incorporated]] (MMI), in [[Denver, Colorado]], opened by Stine and others. Stine had model rocket engines made by a local fireworks company recommended by Carlisle, but reliability and delivery problems forced Stine to approach others. Stine eventually approached [[Vernon Estes]], the son of a local [[fireworks]] maker. Estes founded [[Estes Industries]] in 1958 in Denver, Colorado and developed a high-speed automated machine for manufacturing solid model rocket motors for MMI. The machine, nicknamed "Mabel", made low-cost motors with great reliability, and did so in quantities much greater than Stine needed. Stine's business faltered and this enabled Estes to market the motors separately. Subsequently, he began marketing model rocket kits in 1960, and eventually, Estes dominated the market. Estes moved his company to [[Penrose, Colorado]] in 1961. Estes Industries was acquired by [[Damon Industries]] in 1970. It continues to operate in Penrose today.<ref>{{cite web|url=http://www.estesrockets.com/about-estes |title=About Estes |publisher=Estes Rockets.com |access-date=2012-07-06}}</ref>

Competitors like Centuri and Cox came and went in America during the 1960s, 1970s, and 1980s, but Estes continued to control the American market, offering discounts to schools and clubs like [[Boy Scouts of America]] to help grow the hobby.<ref>{{cite web |url=http://www2.estesrockets.com/cgi-bin/wedu001P.pgm?p=youth |title=Estes Rockets |publisher=Estes Rockets |access-date=2012-07-06 |archive-url=https://web.archive.org/web/20160304075155/http://www2.estesrockets.com/cgi-bin/wedu001P.pgm?p=youth |archive-date=2016-03-04 |url-status=dead }}</ref>  In recent years, companies like [[Quest Aerospace]]<ref>{{cite web |url=http://www.questaerospace.com/index.asp |title=Great Buys Check Out Other Value Packs |publisher=Quest Aerospace |date=2009-11-26 |access-date=2012-07-06 |archive-url=https://web.archive.org/web/20160304042829/http://www.questaerospace.com/index.asp |archive-date=2016-03-04 |url-status=dead }}</ref> have taken a small portion of the market, but Estes continues to be the main source of rockets, motors, and launch equipment for the low- to medium-power rocketry hobby today. Estes produces and sells [[Black powder rocket motor|black powder rocket motors]].

Since the advent of [[high-power rocketry]], which began in the mid-1980s with the availability of G- through J-class motors (each letter designation has up to twice the energy of the one before), a number of companies have shared the market for larger and more powerful rockets. By the early 1990s, Aerotech Consumer Aerospace, LOC/Precision, and Public Missiles Limited<ref>{{cite web|url=http://www.publicmissiles.com/ |title=Public Missiles, Ltd. Online Webstore |publisher=Publicmissiles.com |access-date=2012-07-06}}</ref> (PML) had taken up leadership positions, while a host of engine manufacturers provided ever larger motors, and at much higher costs. Companies like Aerotech, Vulcan, and Kosdon were widely popular at launches during this time as high-power rockets routinely broke [[Mach number|Mach 1]] and reached heights over {{convert|3,000|m|ft|abbr=on}}. In a span of about five years, the largest regularly made production motors available reached N, which had the equivalent power of over 1,000 D engines combined, and could lift rockets weighing {{convert|50|kg|lb|abbr=on}} with ease. Custom motor builders continue to operate on the periphery of the market today, often creating propellants that produce [[pyrotechnic colorant|colored flame]] (red, blue, and green being common), black smoke and sparking combinations, as well as occasionally building enormous motors of P, Q, and even R class for special projects such as extreme-altitude attempts over {{convert|17,000|m|ft|abbr=on}}.

High-power motor reliability was a significant issue in the late 1980s and early 1990s, with catastrophic engine failures occurring relatively frequently (est. 1 in 20) in motors of L class or higher. At costs exceeding $300 per motor, the need to find a cheaper and more reliable alternative was apparent. Reloadable motor designs (metal sleeves with screwed-on end caps and filled with cast propellant slugs) were introduced by Aerotech and became very popular over the span of a few years. These metal containers needed only to be cleaned and refilled with propellant and a few throw-away components after each launch. The cost of a "reload" was typically half of a comparable single use motor. While catastrophes at take-off (CATOs) still occur occasionally with reloadable motors (mostly due to poor assembly techniques by the user), the reliability of launches has risen significantly.<ref>{{cite web|url=http://www.arocketry.net/faq.html |title=a Rocket Science Resource for Experimental Rocketeers |publisher=Arocketry.net |date=2005-02-05 |access-date=2012-07-06}}</ref>

It is possible to change the thrust profile of solid-propellant motors by selecting different propellant designs. Since thrust is proportional to burning surface area, propellant slugs can be shaped to produce very high thrust for a second or two, or to have a lower thrust that continues for an extended time. Depending on the weight of the rocket and the maximum speed threshold of the airframe and fins, appropriate motor choices can be used to maximize performance and the chance of successful recovery.

Aerotech, Cesaroni, Rouse-Tech, Loki and others have standardized around a set of common reload sizes such that customers have great flexibility in their hardware and reload selections, while there continues to be an avid group of custom engine builders who create unique designs and occasionally offer them for sale.<ref>{{cite web |url=http://www.bellevillehobby.com/custom.aspx |title=Estes Rockets, Model Rockets, Rocket Engines-Belleville Wholesale Hobby - Custom |publisher=dumbledore.com |access-date=2012-07-06 |url-status=dead |archive-url=https://web.archive.org/web/20120630012435/http://www.bellevillehobby.com/custom.aspx |archive-date=2012-06-30 }}</ref>