Route89 wrote:
I've come up with what I think is a good, original design for an
ultralight or ARV airplane, and I've reached the point where I'm
considering actually building and flying a full scale airplane. I've
built and flown many R/C models, 1/6, 1/4, and 1/3 scale, I've been to
Osh Kosh for the past 20 years, etc. I'd like to post some pictures of
it on this forum to get some reactions, advice, and suggestions,

There is no need to make your design that public at this point if you are
that worried. If you haven't already done this, first locate the nearest
local EAA chapter and join it. You can then ask for help there and you will
likely get better feedback than using an online forum. They are unlikely to
steal your ideas - and you even have the option of asking if any
prospective reviewers object to signing an NDA (non-disclosure agreement)
before revealing your design details to them. That is not something you can
do online.