Mister Spock’s “Jeppesen CSG-1 Pocket Flight Computer”

One of those obscure props that shows up from time to time in Star Trek is what’s called an “E-6B Flight Computer”–sometimes affectionately called a “whiz wheel.”  Probably the best shot of this prop is from the episode “The Naked Time” (Episode 4)–where Mister Spock uses the device to somehow help him calculate some of the details of the breakup of the planet Psi 2000).  Here’s a screen grab:

Mister Spock with Jeppesen CSG-1


Its actual first appearance is one episode earlier–in the episode “The Corbomite Maneuver” (Episode 3)–where it can be seen lying on the table right about at Mr. Scott’s hand as the senior officers gather in the Briefing Room to discuss options:

CSG-1 Lying on the Tabletop

It can also be seen in the episode “Wolf In the Fold” (Episode 36) where Mr. Spock uses the device to help him in making preparations to have the ship’s computer calculate the value of Pi to the “last” digit:

Mister Spock with CSG-1

The last time we see this little device is in the episode “The Deadly Years” (Episode 40).  Lieutenant Sulu is noodling with it during his “Roll over, Chekov!  Breath deeply, Chekov!” conversation with the young Russian Ensign sitting next to him:

Sulu Noodles Around with a CSG-1

Of course, “E-6B Flight Computers” are real live slide rule type devices.  They are handheld slide rule devices used by pilots to help calculate such things as fuel burn rates, wind correction, time en route, and ground speed.  Although they look kind of archaic, some pilots actually prefer to use them even today rather than more modern “Flight Computers” that resemble present day calculators.  (These E-6B slide rules are lightweight and they don’t run the risk of having batteries fail at an inopportune time!)  There are measurements and scales on both the front of the device (called the “calculator side”) and the back of the device (called the “wind side”), so an E-6B is two slide rule tools in one.

At any rate, a number of aviation supply manufacturers over the years have produced E-6Bs.  The one seen in the Star Trek screen shots was manufactured in the 1950s by Jeppesen and Company in Denver, Colorado.  Just as one famous brand of cola soft drink is called Coca-Cola, Jeppesen called their particular brand of E-6B flight calculator a “CSG” (“Slide Graphic Computer”).  Jeppesen actually made two sizes of CSG (although they are identical in all ways other than size): a small “Pocket” CSG-1 (which is small enough to fit in a breast pocket but which is a bit harder to read) and a larger “Navigator” CSG-2.  The CSG-2 is actually the more popular size among pilots.  (Its larger size (nine and half inches) probably makes it much easier to read than the smaller size (six and half inches).  Apparently nine and half inches is better than six and half inches–and size does matter to pilots.  Badda bing!  Thank you– I’m here all week!)

The one in these Star Trek screen shots is the smaller “Pocket” CSG-1.  Since both Gene Roddenberry and Star Trek Art Designer Matt Jefferies were accomplished pilots, the prop actually seen on the series very likely belonged to one of them.  I suppose in 1966 and 1967, it looked very futuristic and looked like something that might be used in the 23rd century.

I have some pictures of my 1950s vintage Jeppesen and Company “CSG-1 Flight Computer.”  Here are the front and back with the device disassembled into its two components:

Front and back, properly assembled:

What’s not immediately obvious (unless you’re a pilot, I suppose–and you look very carefully at the screen shot from “The Naked Time”) is that the rectangular slide part of the CSG-1 Mister Spock holds in “The Naked Time” has been completely removed from the round wheel part, flipped over face down, and then reinserted.  So the “calculator side” of the wheel is trying to perform measurements on the “wind side” scales–and vice versa–which iwould just yield a bunch of meaningless data.

So here are two shots of my CSG-1 assembled incorrectly–just like Mister Spock’s:

And just for good measure–a close up of some of the markings on the device:



By the way, Jeppesen made two different CSG-1: one was made out of aluminum (the CSG-1A) and one was made out of plastic (the CSG-1P).  Other than the manufacturing material, the two CSG-1s were otherwise identical.)    

I don’t know if we’ll see this device in any upcoming Star Trek Phase II episodes.  (Unlike back in 1966, the high definition cameras nowadays can probably make out the anachronistic writing on this device.)  But you never know.  Perhaps Mister Spock or Mr. Scott might once again need to resort to this handheld device to help them with their complex calculations.

More about E-6Bs can be found at:


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Author Greg Schnitzer

Gregory L. Schnitzer is Co-Executive Producer on the fan-based Internet series Star Trek New Voyages/Phase II (formerly known as Star Trek New Voyages). Greg is a Registered Nurse and is often in charge of Emergency Medical Services at the Star Trek New Voyages/Phase II shoots. He is also the production's Property Master and on-again, off-again Set Decorator. Born and raised in Los Angeles (which he still calls "home"), in real life, Greg is a Registered Nurse, currently working in Health Information Management at a variety of medical facilities in the greater metropolitan Washington, D.C., area. Find Greg's page on the IMDB at: http://www.imdb.com/name/nm3348883

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