Bits and Pieces
Building Six CH 750s at the Same Time!
By Glen Brown
Printed with permission from Glen Brown and Zenair News
Greetings. We’re a group of six aviation enthusiasts (all members of the Lethbridge Sport Flyers club) in Alberta, Canada, who all have our own aircraft:
Guy Bishoff – Team Mini-Max; Joe Harrington – Beaver RX550; Dave VanDyke – Hipps Reliant; Lawrence VanEgmond – Team Mini-Max; Glen Brown – Challenger II; Travis Corbin – Van’s RV-9.
We somehow started gathering for coffee at 7:30 Sunday mornings, whilst our wives slept, to talk about flying and airplanes. (Sound familiar?) I suppose there were a few lies told, too, because we eventually became known as the Liar’s Club. After about a year or so, we kind of decided that we should be doing something constructive with our Sunday mornings instead of sitting and getting fatter. So it was suggested that perhaps we should build an airplane. Then the discussions started about what type and how and where, whether kit or plans, and if we were smart enough, or even if we liked each other enough, etc.
This kind of talk went on for a long time (more lies told) until one member, Travis, called the group’s bluff and ordered a tail kit for a Van’s RV-3. An RV-3? What the heck? As you can see from the group list, he’s the only one who is flying a fast plane; the rest of us are low and slow kind of guys. Then the discussions about aircraft type really started in earnest, and we finally decided that the new Zenith CH 750 would fit our group the best for the kind of flying we like to do. In addition, the all-aluminum design might be something our group could build. We had heard the kits were pretty good.
But how could we test to see if this idea would work for our group before committing to a kit? Why not order a set of plans and build a rudder? So on February 28, 2009, plans in hand, we cut out our first rib blanks. Right off the start, we realized that making six parts was almost as easy as making one, and aluminum was cheaper in bigger quantities. One rudder quickly became six. Six guys became a production line for measuring, cutting, forming, deburring, riveting, etc., and we all just barely fit in a 20 x 24-foot garage. A little over a month later, we had a working shop set up, some equipment bought (small bending brake and shear), and six rudders done. This was getting serious.
Now that we were committed (one thing had seemed to lead to another), there was no choice but to order more aluminum, get legal, order five more sets of plans, and then get busy. Our build schedule is Monday night, Wednesday night, and Saturday, and we have kept to it quite well since we started. Guy is the undeclared mother hen of the group; it’s his garage and he has had the most building experience, having completed a plans-built Team Mini-Max and made substantial progress on a plans-built Pazmany PL-1. His Pazmany project is on hold until the CH 750 is done.
Even though the group’s previous aircraft building experience was limited to Lawrence, who also completed a plans-built Mini-Max, and Guy, we all have contributed significantly to the
project. Besides hands-on construction, which the group seems to do very well, individuals bring to the table different talents, connections, etc. We’ve reproduced many of the CH 750 parts on AutoCAD, and using these files, we’ve water jetted to exact dimensions many of the heavier-gauge parts and even some aluminum-form blocks. The aluminum-form blocks worked really well when we routered the wing ribs and the spar webs, and they stood up better than wood when hammering so many rib flanges. As we complete parts, we remove them to Lawrence’s shop where they’re to be stored until inspection, then closing, and then eventually moved again for painting and assembly. So far, we’ve completed six rudders, elevators, horizontal stabilizers, and skeletons for the flaperons. We have all the wing ribs done, and we completed all twelve spars just before Christmas. That was a major milestone for us. The rear channels will be started in January.
We’re still having fun, and no one has been killed yet, even though it’s a small shop for six big guys. We’re learning a lot about aviation construction practices and standards; the group is a great motivation for consistent building. We’ve all agreed this plans-build project wouldn’t have happened if we were going at it individually. The CH 750 is a great design, and much of our talk during the build has been about what flying adventures we’ll experience when we have six completed sky jeeps.
The real irony of this project? We’re still meeting every Sunday morning for coffee. Go figure ...