EAA Sport Aviation - August 2011

Though it may seem spartan to some, it is comfortable and totally functional for long-distance VFR flight, day or night.

We anticipate that builders will customize and will add weight in the process. This does not mean that there are not compromises or penalties involved. At the very least, any added weight will subtract from the useful load of the airplane. This is the reason that so many four-seat factory airplanes cannot fly with full seats and full fuel at the same time. But for homebuilt aircraft, this is a compromise any builder has the freedom to make, and many do. But adding 248 pounds of “stuff” is rather extreme. It is the equivalent of adding the weight of an entire ultralight, engine and all. It’s almost equivalent to adding another pair of RV- 10 wings.

GROSS WEIGHT

The spec sheet also notes Greg’s airplane
has a listed gross weight of 2,800 pounds
instead of the 2,700 pounds the factory spec-
ifies. Yes, we realize that a builder of an
experimental amateur-built airplane can list
any gross weight or flight limits he wishes.
It’s just that we don’t accept that. Our fac-
tory specified gross weight is based on the
best science we have available. This includes
careful stress analysis calculations and

We anticipate that builders will customize and will add weight in the process. This does not mean that there are not compromises or penalties involved.

extensive static load and flight limit testing.
We wonder what basis Greg (or any other
builder who uses a higher-than-recom-
mended gross weight) uses for establishing
the 2,800-pound gross weight of his air-
plane? If it isn’t based on the same science
and testing, we simply cannot recognize it as
valid, and neither should anyone else. Any
“penciled in” gross weight increase is just
wishful thinking. The laws of physics are not
repealed by wishful thinking.

HARNESSES

But this discussion of payload trade-offs is not the primary purpose of this article. While we hate to see our laboriously designed four-seat payload erode to a two-and-a-half-seat limit, that is the builder’s privilege. Our primary purpose here is to point out several modifications made to primary flight control systems and safety features. We feel these are detrimental to safety, and that readers and other RV- 10 builders should be aware of our concerns. Modifications undertaken for otherwise good reasons can have negative consequences.