> > Perry just as a matter of interest please try a forward slip
at high
> > altitude and
> > tell us what happens. For example is the canard stable or
> > does it buck in yaw or pitch? I am curious. The C 172 with full
> > flaps pitch bucks a little bit in a forward slip.
> >
> > Paul Lamar
>
> All Cessna's that I've flown do this.. I think you'll find that
most [if
> not all] Cessna singles [ other than the 208 which I've not
flown] are not
> approved for slip's w/ full flaps. I used to get into a divergently
> unstable pitch situation all the time w/ a 182 when flying
skydivers.. it
> was controllable when you were expecting it.. when you weren't [
the first
> few times it happened] it got your heart pumping.. Mind you..
these where
> Max rudder on a straight tail 182, w/ enough bank to keep the
heading> straight and then forward pitch until you reached Vfe and
hold it there..
> w/ about 17inch MAP. Used to go from 2000 asl to 12000 and back to
> 2000[surface] in 18 minutes.. The other way to do it was Vne and
no flaps
> and 17"MAP.. but in the summer bump's you'd lose sight of the
wing tip's
> during the bumps.. not a really secure feeling.. We got paid by
the trip so
> the faster the better.. :-) 27 trips in 1 day was enough to wear
ya out
>
> Jarrett
>
>
> Why do you think they are not approved for slips Jarrett?
> Was it the pitch buck or was it some other reason?
>
> I have always known that but it does not bother me to do them
> anyway in my angled tail 182. As far as I can tell it does not
> pitch buck like a 172. Maybe I am doing them wrong :)
>
> Of course you can run out of gas as all the gas tends to
> flow to the lower wing when the tank selector is on both.
> But then again you are landing usually so you should not care
> if the engine quits. Never the less I set the selector to the
> upper wing. There is a scenario where someone may pull out on
> the runway at the last minute.
>
> Paul Lamar ...No rotor no motor.
I've got quite a bit of Cessna time, and I had an instructor who made
me slip a lot. The explanation I remember is that 40 deg. flaps could
blank the tail surfaces which could cause loss of control. We would
slip as much as we wanted with 20 deg flaps or less. Jarrett's
divergently unstable pitch situation seems like a good situation to
avoid.
Bob W.
Bob, I had wondered about that also. It's only worry-some the first time
it happens, after that its just what-ever. It would make sense that
it blanks out the tail. After blanking the tail, the Cm [moment of pitch]
w/ the flaps out would put a huge nose down force out. This would cause the
nose to drop, then as the change in pitch happens the tail is
re-exposed to proper airflow and the pitch authority comes back. However
the pitch authority is that you want it to move back into the area of
blanked airflow [your pullin' back on the yoke thinking "This thing has a mind
of its own!" ] and so the occilation continues. It's been 6 yrs since I
flew divers or pushed a single engine Cessna that hard so my memory
is a bit foggy but I think it was controlable if you over controled or moved
the control's more than you'd normally move them [ie; 3-4" instead of the
normal ~1"]. It got so that you'd just kinda ride along as it went through
the occilations and then pop it straight when you got lower.. It didn't bother
me to much after the first couple of times and I didn't pay it much heed after that.
Fwiw...
Jarrett [ don't take this as a recommendation to go do it all day long :-D]
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