limit of trim = limit of travel?
On May 5, 5:55 pm, WingFlaps wrote:
Does the elevator lift force and stall angle reflect trim setting at
all?
Cheers
Probably to some rather minor degree. The government just demands
that the airplane behave in certain ways in various configurations and
maneuvers, so the designers have to build their airplanes to fit
within those specs. An elevator should never stall before the wing,
for example, or the whole machine could flip over onto its back. The
rising tail, rising because the stab/elevator stalled, would
experience an even higher AOA as it rose and things would get very
nasty. The certification guys want the nose to drop gently as the wing
stalls, which couldn't happen if the stab let go too soon. Some
airplanes (I.E. Ercoupe) had limited up-elevator to prevent wing stall
and therefore the stall/spin scenario that killed so many in the '40s
and '50s. The nose didn't drop because the wing stalled but because
the stab/elevator ran out of nose-up authority. It could easily have
been modified to get the stall. There was plenty of area there. Only
problem was that guys would get slow on final and pancake into the
ground and break their backs with compression fractures. Don't
necessarily need to stall to get killed.
The Cessna Cardinal had a problem early on with the stabilator
stalling in the landing flare and smashing the nosewheel on pretty
hard, and they fixed that with a slot in the leading edge of the
stabilator. IIRC the ground effect had something to do with the stab
stall problem. I never had any such thing happen at altitude in the
'68 (non-slotted) Cardinals.
Dan
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