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One of the
monthly columns in R/C Modeler magazine, written by Chuck Cunningham, entitled
"Cunningham on R/C," that reported on the current state of radio control, which
had only fairly recently evolved into fully solid state, proportional control systems.
Anyone involved in electronics is painfully familiar with the weird kinds of issues
that crop up in complex circuits that operate in hostile environments. The March
1970 issue contained part of an article authored by D. L. Klipstein, Director of
Engineering, Measurement Control Devices, entitled, "Murphy's Law: The Contributions of Edsel Murphy to
the Understanding of the Behaviour of Inanimate Objects.*" Only a few of the
items were printed in Cunningham's column, but I managed to locate a copy of the
full article on the
Archive.org website. He must have selected those
which he figured were most applicable to radio control systems.
* E.E.E. Magazine (Electronic Equipment Engineering,
merged with EDN), Vol. 15, No. 8, August, 1967, pp. 91,92
Edsel Murphy's Law (Cunningham on R/C excerpt"
 The other day I was having a hard time obtaining
a special part that I had purchased for my company. Production of a large contract
had been stopped because the supplier had shipped the wrong part. All of the paper
work was correct, but the guy in the shipping department had put the wrong size
part in the box. The correct parts had to be air freighted in and, even so, the
project was held up for four days. A friend of mine in the suppliers office mailed
me an article clipped from an Electrical Engineering magazine. It was titled, "Edsel
Murphy's Law Governing Inanimate Objects." Perhaps some of you have been exposed
to Edsel Murphy's Law, or know what it is. Simply stated it means, "What ever can
go wrong, will." Or, expressed mathematically 1 + 1 ~ 2, where the symbol ~ means
"seldom ever." The article went on to point our many applications of Murphy's law
as it related to electrical engineering. These seemed to be related to the sport
of R/C. I've included some of Murphy's laws as shown below:
- All warranty and guarantee clauses become void upon payment of invoice.
- The necessity of making major design changes increases as the fabrication of
the model approaches completion.
- Original drawings will be lost in the mail.
- Any error that can creep in, will. It will be in the direction that will do
the most damage.
- Any wire cut to length will be too short. (The same goes for a piece of balsa
wood.)
- Identical units tested under identical conditions will not be identical in the
field.
- The availability of an item is inversely proportional to the need for that item.
- A dropped tool will land where it can do the most damage. (Also known as the
law of selective gravitation.
- A device selected at random from a group having 99% reliability, will be a member
of the 1% group.
- The probability of a dimension being omitted from a plan or drawing is directly
proportional to its importance.
- Interchangeable parts won't.
- If a prototype functions perfectly, subsequent production units will malfunction.
- Components that must not and cannot be assembled improperly will be.
- If a circuit cannot fail, it will.
- The most delicate component will drop.
- A fail-safe circuit will destroy others.
- A transistor protected by a fast-acting fuse will protect the fuse by blowing.
- A failure will not appear until a unit has passed final inspection.
- If an obviously defective component is replaced in an instrument with an intermittent
fault, the fault will reappear after the instrument is returned to service.
- After an instrument has been fully assembled, extra components will be found
on the bench.
My thanks to "D. L. Klipstein" who authored this article. in the first place.
If you can't find a bunch of parallel situations in our hobby, be it in construction
aircraft, or repair of radio sets, then you'd better get back to work, and skip
all of this reading jazz.
Good luck, and good flying. When the snow melts, that is!
Posted May 15, 2019
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