All very helpful and interesting stuff. Thanks a lot.
Gerry
"Jim Logajan" wrote in message
.. .
"pTooner" wrote:
Firstly, I am new here although I've been reading for a few days. For
anyone with more knowledge than I, I keep considering building a small
4 wing aircraft. Not stacked, but two up front and two in the rear.
I have read frequently of problems supposedly resulting from
interference of the airflow between wings, but I can't seem to find
anything very specific.

Theory of biplanes might provide the theoretical basis. My copy of
"Theoretical Aerodynamics" by L. M. Milne-Thomson discusses wing
interference between the wings of biplanes in chapter 8. (It's a Dover
publication, so it is still in print and inexpensive.)

Also, try a Google search on this set of search words (with or without
the search word "stagger"):
aerodynamic gap biplanes

I'm fairly confident that interference
between the front wings (or rear) can be minimized by reasonable
spacing and differing dihedral.

Staggering the wings tends to help reduce interference also.

I'm not sure what the effect of the
airflow coming off the front wings will have on the rear set. I don't
know whether I could remove most of the problem by having one set
considerably higher (how much?) than the other set or if it is
reasonable to have them on more or less the same height.

I suspect having one set high that the other would equivalent to a large
staggering angle.

The reason
for the concept is trying to get a wingspan small enough to fit into a
normal garage and conceivably take off and land from streets and
highways. I visualise something in a two place plane that would fall
into something of the appeal category of a motorcycle or small sports
car. Any thoughts would be appreciated.

If you are not already familiar with it, you should browse this site,
which include planes that attempt to satisfy some of your requirements
(the Wernicke Aircar uses low aspect ratio wings to try to meet some of
your requirements):
http://www.roadabletimes.com/