Readers Sound Off

By Design News Staff -- Design News, February 3, 2004

G ONSET OVERLOOKED?

I read your article on the centrifuge simulator (DN 12.01.03), but I was not convinced. I have spent almost 30 years designing and testing simulators for military fighters and helicopters. I'm also a pilot and have experienced elevated G's in the cockpit. I have a solid understanding of aerodynamics and physics and have had to apply that knowledge in making the simulator visual and motion cues respond correctly within the physical constraints of ground system. I know how centrifuges work but do not, even after reading your article, believe that they can be realistically used to simulate the onset and the offset of high "G" in a ground-based simulator. The only number reference to G onset in your article is in fine print at the bottom of one page. I don't believe they can produce a 6-G onset in 1.4 seconds and still keep the G-vector aligned in the correct axis.

George T. (Tom) Humphrey, HOUSTON, TX

ACRONYMED OUT

While I agree with Consultant Dick Miller on the uselessness of "new" programs having nothing more to offer than a different name for the same thing (DN RANT 12.01.03), he committed the cardinal sin (in my opinion) of using an acronym (PLM) without telling us what it stands for.

Larry E. Fry, SAN DIEGO, CA

REAL ROI IS UPSTREAM FROM PLM

I applaud Dick Miller's courage for calling PLM a fancy acronym for simple collaboration, and will fail to produce substantive gains. While I do not wish to disparage PLM, my company—Invention Machine Corp.—believes that the real ROI will be found upstream from PLM at the initial innovation stage.

Today, organizations can apply processes and tools to accelerate idea creation and new product development; improve existing products; and bring structure and predictability to invention without sacrificing creativity. This innovation stage, experts say, consumes 70 to 80 percent of a product's development costs. Understanding this, Global 5000 manufacturing clients today apply software that speeds and optimizes the innovation process during product conception and product enhancement. Moving beyond collaboration and simple work flow, innovation-process software requires several critical components:

A problem analyzer drawing from scientific effects across industries.
Solution-generating methodologies that bring structure, discipline and predictability to the art of innovation.
Access to "deep knowledge" spanning many industries and scientific disciplines, which is not available from conventional search engines and knowledge portals.

Innovators need more than collaboration and workflow—fast pinpoint access to information that helps eliminate reinvention of existing products, avoids infringement on intellectual property, provides product engineers with insight into the latest competitive offerings, and reduces the number of time- and resource-sinking ideas that fail to make it to commercialization. R&D dollars are much better spent upstream of PLM—"concentrating on innovation" as Mr. Miller points out.

Mark Atkins, BOSTON, MA

Engineer Bernhard Richter's Response: Yes, we can create 6 G/sec onset. Actually our newest centrifuge, the one the article is written around, has a 10 G/sec onset. First of all, the inertia of the arm has to be as low as possible to be able to accelerate the arm fast enough with a feasible drive system. Feasible means a system that can be powered from a high voltage grid without needing a personal power station. The drive is pulling 6,000 hp during a 10 G/sec onset segment. Secondly, the pitch and roll drives have to have the capability to move quick enough to align the G vector into the Gz direction, i.e., into the pilot's seat of the pants. To align the G vector during a 10 G/sec onset segment from 1.4 to 9 G, the gondola has to be pitched forward and back by approximately 50 degrees in 1.029 sec. Yes, this is pretty fast, but with a tandem drive of two motors driving the pitch and roll axes, it can be done.

I'M A CSI FAN, TOO!

Just wanted to say that your back page "Calamities" column is the first page I turn to when I get my copy each month. I really enjoy all the colorful stories you present along with the little 'mini science' introductions.

Joel Peavy, SAN DIEGO, CA

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