In choosing to build an airplane, selecting a kit is only the first step. There are various decisions that must be made in the path to completing an airplane. In some cases, the kit designer explicitly gives a builder freedom to choose between several options, forcing a decision to be made (see photo of CH 701 with folding wing option). These customizations, approved by the designer, are discussed here. In other cases, the builder knowingly goes outside of the intended design of the aircraft in order to (attempt to) improve it in some way. These unapproved modifications are discussed elsewhere.

The CH 701 is designed for a wide variety of engines. By far the most common, and the ones recommended by Zenith, are the Rotax 912/912S family. There are many other purpose-built aviation engines available, though, including those by Jabiru, ULPower, Continental, and Lycoming. And their are kits available for converting Subaru, Volkswagen, Corvair, and other auto engines for aircraft use. Even motorcycle engines have been tried (see photo of Harley-Davidson engine in a CH 701, borrowed from Zenith). Read more...

Because the CH 701 can accept many different engines, it can also accept many different propellers. Unlike with engines, where Zenith gives very specific guidance and recommendations, there is no specifically recommended propeller for the CH 701. On their factory demo plane with a Rotax 912S engine Zenith currently uses a Warp Drive ground-adjustable propeller. Sensenich fixed pitch propellers are also well-regarded in the CH 701 builder community. Dozens of other manufacturers are out there (see photo of a Savannah with a colorful Brolga propeller, borrowed from StolSpeed Aerodynamics). Read more...

The CH 701 was specifically designed as a tricycle gear airplane, and the vast majority of them have been built that way. However, there is always a certain demand for conventional (tail-dragger) gear, especially in bush planes, and Zenith offers a free designer-approved plans supplement for building a CH 701 TD (see photo of Mike Sinclair's N701TD, borrowed from Zenith). This option complicates the build, decreases take-off performance, reduces resale value, and increases insurance costs. Why would anyone consider it? Read more...

The CH 701 kit now comes standard with bubble doors (see photo of unknown CH 701, borrowed from Zenith). Classic doors are still available, but decrease visibility. A third option, omitting doors entirely, is also an approved option. Trade-offs here are cost, weight, and visibility. Read more...

The CH 701 kit is available with an electric trim option. (Note that contrary to the illustration on that page, the CH 701 trim tab trails the elevator, rather than being integrated with it; see photo of Taiwanese CH 701, borrowed from Zenith.) The supported alternative to electric trim is no trim at all; there is no manual trim option. As the CH 701 intended for shorter flights and has very light stick forces, building it without trim control is not completely unreasonable, and adding trim tabs and actuators adds weight in the very rear of an already tail-heavy plane. Read more...

While the CH 701 specifies the size and location of an instrument panel, all details are left up to the builder. While there are no required instruments for daytime VFR flight in an experimental aircraft, safety and expanded capabilities lead to a desire for a well-equipped panel. Taken to an extreme, it is possible to equip for full IFR operations (EAA member link). And for each instrument, there's a choice between conventional gauges (see photo of conventional panel, borrowed from Zenith) or glass. Read more...

Finally, after the plane is built and tested, it must be painted. Or perhaps not. Finishing options for all-metal planes include a wide variety of paint jobs (see photo of a rather creative one, borrowed from Zenith), bare unfinished aluminum, or aluminum polished to a mirror shine. Issues include not only aesthetics, but also building time, corrosion resistance and weight. Read more...