Topband: Laser distance meters

[Roy Morgan]

Topbanders interested in laser measurements,

Here are some short stories.  During the time I worked at NIST (formerly NBS), I heard about these situation:

The David Taylor Model Basin (since renamed) has a water-filled tank about 5/8 mile long for towing of scale models of ships to measure their performance. A team from the mechanical metrology group at NBS measured the flatness of the rails that carried the instrumented platform along the tank.  Their laser measurement systems found the middle of the tank to be about 5/8 inch above the expected straight line end to end.  It was the curvature of the earth causing the “bulge”.

At a presentation to aircraft manufacturers about measurement systems being developed to more accurately make the major components of commercial aircraft, many of which were being made at different locations, the speaker noted that the Boeing 747 was assembled with shims to compensate for differences between major parts that had to fit together (wings, fuselage sections). “The 747 has a ton of shims”, he’d said.  “Wait a minute”, one Boeing engineer said, “How much do all those shims weigh?”  About a ton, was the reply - nearly two thousand pounds.  And that weight gets carried by the aircraft throughout its life.

The NIST metrology building houses a highly accurately located GPS receiver to develop error information that is broadcast by radio (and presumably internet) useful for land surveyors to correct their laser surveying instrument results.  (One of the US’s primary geolocation points is on the NIST grounds and forms the basis for all surveying done in the Eastern part of the continent.)

 
> On Jun 6, 2021, at 12:58 AM, Richard (Rick) Karlquist <richard at karlquist.com> wrote:
> 
> I am considering replacing my 100 meter tape measures with
> a Bosch GLM400CL laser distance meter to use for laying out
> my next 160 meter circular array.  I am wondering if anyone
> has any experience with this model or any other models that
> work to a range of 100 meters.  (That spec eliminates the vast
> majority of meters).  How important are accessories like
> tripods and target cards?
> 
> 73
> Rick N6RK
> _________________
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Roy Morgan
K1LKY since 1958
k1lky68 at gmail.com
Western Mass