Propellantless thrust?

Rather stupidly written. Propulsion systems don't produce "Gs" of thrust. pounds of thrust, gram-force of thrust, newtons of thrust, yeah, but not "one Earth gravity of thrust". THAT depends on the mass of the object it is trying to propel.

In the text of the article, it mentions that the motor is 30 grams, and produces 30 grams of thrust. Doesn't say how much power is required, and ESPECIALLY doesn't say whether the power source is included in the 30 grams. If the motor produces 30 grams of thrust, but the motor has to be connected to Grand Coulee Dam, you ain't going nowhere.

The factor that shows the efficiency of a propulsion system is the Specific Impulse (Isp). For existing propulsion systems, the Specific Impulses will range from ~190 to ~3000 seconds. The motor with an Isp of 3000 will only burn about 1/20th of the fuel as an engine with an Isp of 190. The motors with the high specific impulses are usually electric (ion, etc.) and produce micrograms of thrust.

But, again, the article doesn't mention the Specific Impulse...critical to understanding what's going on.

Ron Wanttaja
 
I forwarded the article to one of my fellow retirees, who worked propulsion through his entire career, including developing electronic propulsion. His comment echoed the classic, "Extraordinary claims require extraordinary proof." He says these have come up over the years, but none of them have gone anywhere. Also, he says "tests that involve tiny thrust forces [which is what we're talking about, here] on low-mass films find it difficult to exclude other effects."

They should have no problem setting up a public demonstration in front of neutral observers (e.g., industry experts). But they never do.

Ron Wanttaja
 
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