* Posts by testpilot

4 posts • joined 23 Apr 2012

Cabling horrors unplugged: Reg readers reveal worst nightmares

testpilot

Back in the days of analog amateur radio (although come to think of it, Morse code is essentially binary), my station sported three full-height racks including a massive 1 KW transmitter (American legal limit) with evilly-glowing tubes...sorry, valves...and even eviller Hg-vapor rectifiers in its power supply. Everything was strung together with the usual (night)mare's nest of everything from lamp cord and doorbell wire through shielded audio wire to heavy 50 Ohm coax...not to mention heavy high-voltage lines, flexible cooling air ducts, and copper plumbing for the transmitter power supply's water cooling. Of course, everything except the plumbing was black.

A visiting fellow "ham" from the UK, gazing at this with wild surmise, took his boffin-grade pipe out of his mouth long enough to remark, " y'know, I really don't understand why back Home we still call this 'wireless'..."

Experts stroke beards over LOHAN's vacuity

testpilot
Alert

vacuum gauge protection

I agree with the various comments w/r/t cold traps and, possibly, large vacuum reservoirs. Note, however, that the latter represent considerable stored energy--not only will they require proportionally longer time to pump down, but there's a risk of implosion (or at least collapse) with a mighty bang and possible shrapnel.

As far as protecting the costly vacuum gauge is concerned, you might consider simply placing it at the end of a much longer line, and possibly installing very small orifices at both ends of the line. In addition, you could stuff the line to the gauge with something like steel wool or fiberglass insulation, which would be permeable to air (and its absence) but which would tend to trap particulates, while the orifices would slow gauge response to sudden pressure changes including those which occur when the motor lights off and the REHAB lid is blown away.

Finally, while off-topic:

A Higgs Boson goes into a catholic church. The priest asks it, "what are you doing here?" The Higgs Boson replies, "you can't have Mass without me."

(rimshot)

El Reg official units of measurement: Linguine, Jubs, Hiltons and all

testpilot

unit of feminine pulchritude

The stimulant effect of your attractive boffinettes can be calibrated against the standard Helen (H); Helen of Troy was described as "the face that launched a thousand ships." Most modern women rate at least one millihelen (mH).

1 mH = a face sufficiently lovely to launch one (1) ship.

LOHAN ideas..

testpilot

Re: LOHAN ideas..

Some possible ideas re LOHAN project

First off, I apologize (sorry, apologise—I’m American) if this forum is the wrong place to post these ideas—I’ve tried emailing Mr. Haines directly a couple of times but with no response.

1.) Aircraft configuration:

I realize that by now the Southampton people have probably finalised aircraft design, but I might call your attention to the family of low aspect ratio lifting bodies commonly called Facetmobiles. (As it happens, I was the test pilot for the first human-carrying version, which—among other things—was flown from southern California to the famous Oshkosh, Wisconsin, airshow and back under its own power). See www.facetmobile.com. Note that small-scale unpowered Facetmobiles are regularly dropped from LOHANesque altitudes with scientific instrument payloads and return autonomously to their launch sites; those dropped above 100,000 feet probably exceed M1 during the initial descent.

Facetmobiles offer glide ratios on the order of 6:1, very low structural weight, simple construction (flat surfaces only), and relatively immense internal volume for payload.

Due to its design, a Facetmobile will automatically assume a controllable flight attitude (technical term: carefree re-entry) even if the initial encounter with sensible atmosphere is in an unfavorable attitude (technical term: arsy-versy or, in the USA, ack-basswards).

2.) Launch stabilization:

How about a small but relatively massive (say 50 gm) gyro wheel and brushless electric motor (micro model plane motor) rigidly mounted inside the spacecraft (axis of rotation parallel to spacecraft longitudinal axis). This could be spun up immediately prior to launch (from an inclined rail) by a battery that remains on the launch truss; it would continue spinning long enough to stabilise during powered flight. This would provide rigidity in pitch and yaw until adequate q is attained. As for roll, so long as the thrust vector is properly oriented through the C/G of the vehicle, who cares? (see “carefree re-entry” above).

3.) Recovery:

I call your attention to the Ruby autopilot (www.uthere.com). Weighs about 60 gm, includes its own GPS, plugs into regular RC model servos, costs $345. I’m sure there are many others—I suggest checking websites for the burgeoning FPV (first person video) segment of RC modeling. Note that for the present there are stupid security restrictions that prevent the Ruby from working outside the USA (which means putative terrorists could still use one to control some engine of destruction aimed at domestic targets but not foreign ones…go figure).

Given the planned release altitude, I would hope LOHAN could return to her launch site, metaphorically wagging her tail behind her, even if the balloon system drifts quite a long way downwind during ascent. That said, and considering the export restrictions above, I’d like to close by suggesting…

4.) Where to fly:

The central plains of the USA are not only vast and flat, but crisscrossed by roads at regular one-mile intervals. Not the most dramatic scenery, but ideal for tracking and recovering Unofficial Flying Objects.

Better yet, I’d suggest the annual Burning Man Festival in the Nevada desert (www.burningman.com). Not only is it an (at least) once in a lifetime event to visit, but it includes an ephemeral airstrip on which visitors arrive in everything from Ultralights to turboprops—and there are almost sure to be a couple of helicopters whose owners would very likely be willing to aid in LOHAN recovery.

Best of luck to you all!

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