Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Force of law
(07-20-2015, 11:30 PM)DBMcCann Wrote: Can we forceably annex Cali? (and NYC while we're at it?)

CA has a Proposition system where the electorate can vote by simple majority to change something.  It's constitutionality withstood attack.  One could put a Proposition on the ballot to change the form of government within the state to something more akin to "freestate" and divide the state into 3-4 sub-regions that are managed separately.  One might be the greater bay area, one the greater Los Angeles, San Diego and Santa Barbara region and the remaining two the desert region and the ag and forest region.


Who's in? When we win we can blame CSFM (CA OSFM)
Exemptions not regulations. Please purchase a few rockets from
Thanks. Support eliminating explosive treatment of slow burning solids by DOT.
Thumbs Up 
Rocketman wrote:  "A consumer solid motor is an entirely static device.  No moving parts or mechanisms."

Technically not true.  The combustion products exit the nozzle are very much moving, and are a part of the motor.  In a properly designed motor, those products move at the speed of sound in the nozzle throat.

(07-18-2015, 10:08 AM)Greg Young Wrote: Thanks Greg.  Very good discussion.

Here is MIT's interpretation:

"“The etymologies of ‘motor’ and ‘engine’ reflect the way language evolves to represent what’s happening in the world,” says MIT literature professor Mary Fuller.

The Oxford English Dictionary defines “motor” as a machine that supplies motive power for a vehicle or other device with moving parts. Similarly, it tells us that an engine is a machine with moving parts that converts power into motion. “We use the words interchangeably now,” says Fuller. “But originally, they meant very different things.”

“Motor” is rooted in the Classical Latin movere, “to move.” It first referred to propulsive force, and later, to the person or device that moved something or caused movement. “As the word came through French into English, it was used in the sense of ‘initiator,’ ” says Fuller. “A person could be the motor of a plot or a political organization.” By the end of the 19th century, the Second Industrial Revolution had dotted the landscape with steel mills and factories, steamships and railways, and a new word was needed for the mechanisms that powered them. Rooted in the concept of motion, “motor” was the logical choice, and by 1899, it had entered the vernacular as the word for Duryea and Olds’ newfangled horseless carriages.

“Engine” is from the Latin ingenium: character, mental powers, talent, intellect, or cleverness. In its journey through French and into English, the word came to mean ingenuity, contrivance, and trick or malice. “In the 15th century, it also referred to a physical device: an instrument of torture, an apparatus for catching game, a net, trap, or decoy,” says Fuller.

In the early 19th century, the meanings of motor and engine had already begun to converge, both referring to a mechanism providing propulsive force. “The first recorded use of ‘engine’ to mean an electrical machine driven by a petroleum motor occurs in 1853,” says Fuller.

Today, the words are virtually synonymous. “Language evolves to take on new tasks,” she explains. “Without thinking about it, we adapt to new meanings and leave the old behind.” We talk about our computer’s dashboard, unaware that in the 1840s, the word referred to the board at the front of a carriage that stopped mud from being splashed on the coachman. Similarly, the term “search engine” harks back to the older meaning of “engine” as a contrivance, suggests Fuller. First used in 1984 to mean “a piece of hardware or software,” the phrase may have been informed by Charles Babbage’s 1822 use of “engine” to mean a calculating machine."

Many in the hobby refer to them as engines, as there are no moving parts like motors are presumed to have. I tend to use them interchangeably! Smile
I use "engine" for Estes and Quest, and "motor" for CTI, Aerotech, and Loki, since that's what the manufacturers themselves do.
John S.
NAR #96911
TRA #15253
Level 1, 2014-Mar-15 -- Aerotech Sumo, H133BS
Level 2, 2014-Jun-21 -- Giant Leap Vertical Assault, J240RL
Level 3, 2016-03-12 -- MAC Performance Radial Flyer, M1101WH, 13,028 feet
Meh, it's all muddled up...

Estes and the other manufacturers don't do anything but muddy the water further...

I prefer the terms as they are used in professional rocketry, since our hobby has grown out of that same vernacular...

Professional rocket folks refer to liquid rocket propulsion as ENGINES, and solid rocket propulsion as MOTORS...

Liquid rocket engines invariably use a considerable number of parts to handle, proportion, mix, and burn the propellants to produce thrust... by a number of different means and modes... the simplest mix two hypergolic propellants flowing into the combustion chamber from pressurized tanks which ignite on contact-- but they still have at least two propellant valves and the combustion chamber as part of the engine proper.  When you consider regeneratively cooled bleed-off cycle engines like the SSME, it can get truly dizzying the number of parts they use...  

Solid rocket motors, on the other hand, use basically nothing but the pre-mixed propellant itself and a pressure vessel which acts as the combustion chamber, and the nozzle itself.  It doesn't have to have ANY moving parts, except the entire assembly and the burned and expelled propellant gases from within itself, although it CAN have things like a gimbaled nozzle for stability or a liquid steering fluid injection system for stability.  

SO, if I understand the previous post correctly with the 'definitions' per se, according to the "English teachers" we should technically call solid rocket motors engines, since they do not per se use moving parts, and liquid rocket engines motors because they DO use numerous moving parts??  HERESY I say!!! LOLSmile  Besides, you'd sound really stupid in a room full of rocket engineers referring to solid rocket engines and liquid rocket motors... LOLSmile  

From the ENGINEER'S perspective, a "motor" is something that imparts motion through the application of force generated from an outside source... hence electric motors, which use electrical energy created or stored "elsewhere" and convert it into motion via the windings, magnets, and mechanisms inside the electric motor.  An "engine" on the other hand, imparts motion through the application of force generated from energy produced INSIDE or ALONGSIDE the mechanism, usually as part of it... for instance, internal combustion engines that burn gasoline or diesel, or external combustion engines like steam engines that burn coal or wood or any other number of things... Again, the implication is that a motor uses few parts to impart motion from pre-produced power (say chemical mixtures or electrical energy), whereas an engine uses many parts working in concert to convert a fuel and oxidizer source into motion directly without intermediate steps or storage... (as in batteries, stored pressurized fluid or gas, etc.)  

Either way, what the "English teachers" have to say about it via the etymology of the words themselves in antiquity, really only comes into play for writers, not engineers, and not rocket scientists... Smile  

But the only difference a liquid and a solid is the temperature....   Big Grin
John S.
NAR #96911
TRA #15253
Level 1, 2014-Mar-15 -- Aerotech Sumo, H133BS
Level 2, 2014-Jun-21 -- Giant Leap Vertical Assault, J240RL
Level 3, 2016-03-12 -- MAC Performance Radial Flyer, M1101WH, 13,028 feet

Forum Jump:

Users browsing this thread: 1 Guest(s)