93 Years Ago Today; Robert Goddard launches first liquid-fueled rocket [View all]

[Dennis Donovan]

https://en.wikipedia.org/wiki/Robert_H._Goddard#First_flight



First flight
Goddard launched the first liquid-fueled (gasoline and liquid oxygen) rocket on March 16, 1926, in Auburn, Massachusetts. Present at the launch were his crew chief Henry Sachs, Esther Goddard, and Percy Roope, who was Clark's assistant professor in the physics department. Goddard's diary entry of the event was notable for its understatement:

March 16. Went to Auburn with S[achs] in am. E[sther] and Mr. Roope came out at 1 p.m. Tried rocket at 2.30. It rose 41 feet & went 184 feet, in 2.5 secs., after the lower half of the nozzle burned off. Brought materials to lab. ...

His diary entry the next day elaborated:

March 17, 1926. The first flight with a rocket using liquid propellants was made yesterday at Aunt Effie's farm in Auburn. ... Even though the release was pulled, the rocket did not rise at first, but the flame came out, and there was a steady roar. After a number of seconds it rose, slowly until it cleared the frame, and then at express train speed, curving over to the left, and striking the ice and snow, still going at a rapid rate.

The rocket, which was later dubbed "Nell", rose just 41 feet during a 2.5-second flight that ended 184 feet away in a cabbage field, but it was an important demonstration that liquid fuels and oxidizers were possible propellants for larger rockets. The launch site is now a National Historic Landmark, the Goddard Rocket Launching Site.

Viewers familiar with more modern rocket designs may find it difficult to distinguish the rocket from its launching apparatus in the well-known picture of "Nell". The complete rocket is significantly taller than Goddard, but does not include the pyramidal support structure which he is grasping. The rocket's combustion chamber is the small cylinder at the top; the nozzle is visible beneath it. The fuel tank, which is also part of the rocket, is the larger cylinder opposite Goddard's torso. The fuel tank is directly beneath the nozzle, and is protected from the motor's exhaust by an asbestos cone. Asbestos-wrapped aluminum tubes connect the motor to the tanks, providing both support and fuel transport. This layout is no longer used, since the experiment showed that this was no more stable than placing the combustion chamber and nozzle at the base. By May, after a series of modifications to simplify the plumbing, the combustion chamber and nozzle were placed in the now classic position, at the lower end of the rocket.

Goddard determined early that fins alone were not sufficient to stabilize the rocket in flight and keep it on the desired trajectory in the face of winds aloft and other disturbing forces. He added movable vanes in the exhaust, controlled by a gyroscope, to control and steer his rocket. (The Germans used this technique in their V-2.) He also introduced the more efficient swiveling engine in several rockets, basically the method used to steer large liquid-propellant missiles and launchers today.

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