Cox & Stevens

Cox and Stevens served the growing aviation industry in the 20th century. They were located in Mineola, Long Island, NY next to Roosevelt Field, which was an airport in the day. It was from there that Charles Lindberg took off on his historic solo flight across the Atlantic.

My Dad worked for Lindberg for a short while, and we lived on Long Island not very far from Roosevelt Field. The place had a special meaning to my father, to whom aviation was the miracle of his age. He took me out to Roosevelt Field on more than one occasion, and described the history of the place as he knew it. It reminds me of how technology utterly changes our worldview. Roosevelt Field is now a mall.

B-24 Load Adjuster

This is a rule that slides, but it isn't a slide rule per se. It does the work of adding angular "moments" together to find the center of gravity (COG) of a plane.

On researching this rule, I was surprised to find that a maintenance log must be kept for every plane, recording how the installation or removal of any component shifts the COG. Then, when loading the plane with cargo or personnel, care must be taken to keep the COG within bounds. If the load is distributed badly, the plane won't be able to take off or fly.

Cox and Stevens made Load Adjuster rules for military aircraft to allow a loader to figure out where the COG was after stowing bombs, ammunition and crew on board. It's just a matter of keeping track of how many pounds were put where. Each item creates creates an angular "moment" that varies by the weight and the square of the distance away from the starting COG. If the moments of things put ahead of the COG (toward the nose) and behind the COG (toward the tail) cancel out exactly, the COG doesn't move. If they don't, the rule reveals whether the COG moves too far forward or aft to make the plane flyable.

To use the rule, a technician would first need to know where the COG was for the unladen plane, so he'd look it up in the log. He'd then set the hairline of the cursor at an "index" (see the bottom of the stator) corresponding to that location. The left end of the rule represents the nose, and the right end the tail.

Now the plane consists of multiple compartments, illustrated on the back of the rule. Each compartment has its own weight scale on the front of the slide. Forward compartments' scales increase right to left. Aft compartments' scales go left to right.

The technician would consider the first compartment and move the slide to center the 0 mark of its scale under the hairline. He would then determine how many pounds were to be loaded in the compartment, and move the hairline to the corresponding weight on the compartment's scale. Thus, the hairline would move leftward for each forward compartment, and rightward for each aftward compartment. Where it winds up has to be within the loading range shown at the top of the rule if the plane is going to fly.

These instructions are given briefly on the stator under the slide. There, one also finds a formula to calculate the initial index given the plane's basic weight and basic arm, quantities tracked in the log.

Alternatively, the back of the slide bears a table of basic weights and moments of inertia. In that table, for every 10,000 units of moment above the moment corresponding to a basic weight, the index rises by 1. (Note that the tic spacing for the "moment/1000" scale is the same as that of the index scale.) So the loader can line up the basic weight of the plane with 0 on the index scale, and then move the hairline to the plane's moment/1000 (also from the log) to set the initial index.

Rules were matched to individual planes, and the plane number appears both on the right edge of the rule and on case. This rule was for plane #24426 - see the strap under which the case flap tucks.

The scales are printed on plastic laminate, glued to a frame of some sort of engineered wood-like composite.

Alka Juster

I posted "Story 1" below in the Fall of 2016. A year later, I was stunned to get an email from another Alka Juster owner. Honestly, how many of these could C&S possibly have made, purely as a joke? If any other owner is reading this, please contact me!

I can only find two references to this rule on the net: one is a link to a now-gone site that must once have shown the rule, and the other is a reference to an eBay auction (thanks, Rod Lovett!) from January 2011 when one sold $42.60 after 4 bids. And yet, this dweeby little site of mine has found two Alka Juster owners.

I'm tickled to present what I believe is the only documentation on the web of this perfect example of a "gag rule".

Story 1

Site visitor Joan Rhett contacted me to let me know that her father, Harold Jordan, worked for Cox & Stevens starting in the late 1930's. She says that Cox & Stevens was sold upon the death of its owner, a Mr. Bo Sweeney, to Revere Company of America (a maker of thermocouple wire), in Wallingford, CT.

Joan was kind enough to send me a photo of rule for adjusting a different kind of "load", the Alka Juster. You know, you just have to take the time to have fun with your job! Use the Alka Juster to know how Oiled you are in US Fifths, and to mind your "Fool" level. Note: "grenadine, lemon peel, bitters & olives included in basic weight"!

(Be sure to click on this picture for a detailed view.)

Story 2

Visitor Terry Simonds was a long-time friend of Bo Sweeney's when they both lived in Great Neck, NY - which just happens to also be my home town! Terry wrote:

When I was much younger, (late 40’s early 50’s) I palled about with Bo Sweeney who was a bit older than I (he could drive, I couldn’t). He knew that I fiddled about with electrical things and took me over to Cox & Stevens so I could see what “real electronics” looked like. They were working on load cells at the time as I remember, and I was fascinated. I’ve been in electronics ever since.

A few days after the visit Bo showed up at the front door and handed me the Juster.

The last time I saw Bo was about the mid-1970’s and he hadn’t changed a bit.

I remember Bo telling me that many loadmasters in the US Army Air Service had their morales boosted!

Terry generously provided the following pictures of his "Juster". As they show, Joan Rhett's rule has lost the faceplate of the bottom part of the stator. Terry's pictures also show all the other faces of this rare rule. Again, click these images to see more details.