How Many…How Much?


When you reach the end of a project (an airplane is never really finished, so we just say “the end of a project”), you begin to ask questions about how many “things” or how much time it took. At least, if you’re an engineer you ask those questions – we love to measure things.

Some process improvement wag once said “if you can’t measure it, you can’t manage it”, and there is some truth to that, if you believe in truth at all. And it appears that in this case, we’ve managed to build an airplane that is ready for inspection!

We opened the boxes for this project on about the 12th of November, and here it is, Valentines day (14 February). So that’s roughly 85 days on the calendar. Taking a rough look at the hours spent in the shop, and days away for holidays, travel, and other things, it looks like I averaged about five hours a day working with tools – so somewhere about 425 “contact hours” with the airplane. There are, of course, many more hours spent at the desk looking at manuals, shopping for accessories, and thinking about what I’m going to do when the shop heater has warmed the workspace sufficiently to allow meaningful progress, as opposed to uncontrolled shivering (it is, after all, winter in the northern hemisphere).

As we reach the end of the building phase of the little Subsonex personal jet, here are a couple of pictures that illustrate a few of those trivia statistics you might not think about as you strap into your new airplane.

One way you measure progress on a Sonex kit is by coloring in the completed drawings on the drawing tree. You know when you’re done when you reach the point where there is nothing left to check off!

Of course, one question any metal airplane builder is asked is “how many rivets are there in the airplane?” Well in the case of a Quick-build kit, the answer really is unobtainable for the builder (unless they REALLY have too much time on their hands), but I can show you how many rivets I had to pull on this project, because I saved all of the mandrels. Yes, I am an engineer–of course I saved them all!

And finally, how many boxes do you accumulate in the process? Including the boxes the kit came in, and adding the various accessory cartons and the cardboard from several Aircraft Spruce orders, you get a pile about like this. Now its time to go get that box-cutter and start cleaning up this mess…

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Paul Dye
Paul Dye, KITPLANES® Editor at Large, retired as a Lead Flight Director for NASA’s Human Space Flight program, with 40 years of aerospace experience on everything from Cubs to the Space Shuttle. An avid homebuilder, he began flying and working on airplanes as a teen and has experience with a wide range of construction techniques and materials. He flies an RV-8 and SubSonex jet that he built, an RV-3 that he built with his pilot wife, as well as a Dream Tundra and an electric Xenos motorglider they completed. Currently, they are building an F1 Rocket. A commercially licensed pilot, he has logged over 6000 hours in many different types of aircraft and is an A&P, FAA DAR, EAA Tech Counselor and Flight Advisor; he was formerly a member of the Homebuilder’s Council. He consults and collaborates in aerospace operations and flight-testing projects across the country.


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