"Chris Wells" wrote in message
...

A few questions, for those in the know:

Both of the radio-controlled biplanes I've owned were designed with
the lower wing at a higher AOA, so that it stalled first. They also had
the upper wing farther forward than the lower.



The lower wing that is more rearward is affected by the downwash from the upper forward wing, so the 'relative wind' on
the lower wing comes at it from an angle higher than the relative wind on the aircraft.


If the lower wing stalls, the CG will be a little on the aft side of
the upper wing. Wouldn't it be better for the upper wing to be behind,
so that the CG is a little more forward? I've seen some biplanes like
this, such as the Beech Staggerwing, but most seem to have the upper
wing in front.


The upper forward wing is the one that is normally designed to stall first, unless it is an aerobatic type design where
both wings are designed to stall at the same time (better snap (or flick) rolls, etc).


While my R/C had the ailerons on the lower wing (my other one had no
ailerons), it seems most of the biplanes have them mounted on the upper
wing. It would seem to me that the lower wing would be safer, because
you'd have a harder time tip stalling that way - the upper wing would
be able to keep flying after you tip-stalled the lower one. Why is it
the other way around on most biplanes?


This is a control authority issue. Most bipes I see have the ailerons on the lower wing, and then the more responsive
ones have them on both wings.

Also, it would seem only necessary to put washout in the upper wing,
keeping the lower wing flat. Is this the case with most biplanes, or do
they put washout in both the wings?


--
Chris Wells