>
>      >> 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 really couldn't say Paul, it could be for either of those
>     reasons, I
>      > would tend to think that most people wouldn't do a slip for
>     minutes on
>      > end
>      > so the fuel starvation is then less of a concern, the instability
> in
>      > pitch
>      > is a bit more of an attention getter. Cessna's are ok for
>     slipping w/ the
>      > flap's up so...  most likely its the pitch issue w/ using
>     flaps.  [ I'm
>      > guessin']
>      >
>      > Jarrett
>      >
>      >
>      >
>      > I have always been curious about this and I never found anybody
>      > that knew the reason. A lot of new instructors get freaked
>      > out when they do my bi annuals and I slip it in :)
>      >
>      > Paul Lamar ...No rotor no motor.
>
>
>     I think the Cessna prohibition against slips with flaps is related to
>     the Fowler flap mechanism not being designed for the lateral
> aerodynamic
>     load created by a slip.  I was unaware of the pitch instability issue.
>     I suppose I've not slipped  my '69 C150 J through enough altitude to
>     experience the instability.
>
>     Aubrey
>
>
>
> I used to slip my C150M with partial flaps all the time.  We have a
> couple of fields out here with power lines & I made a habit of dragging
> in high & then slipping down to short final.  Couldn't use full flaps up
> here in our DAs, so I can't comment on behavior at 40-degrees, but at
> 30-degrees it was tame as you could ever ask for -- as Jerry mentioned
> in his response.  Pitch was rock-stable for me.
>
> Mark Supinski
>

The 172R POH states that
"Steep slips should be avoided with flap settings greater than 20 deg. due
to the tendancy of the elevator to oscillate under certain combinations of
airspeed, slip angle, and CG loading."
They are not prohibited, just discouraged.
I seem to remember the nose bobbing up and down a little is all.
Earlier models may be different.

The 152s don't have this issue for some reason. I'm guessing elevator size
among other things.

Ron Freier
Vision 2+2 13B Turbo

 In the Cessna 120, I slip slip slip.... Flaps, what are flaps? At
what temperature are your flaps? I have never slipped for more than
~15 seconds though. I understand fuel starvation may be a problem with
extended slips. I read through the 120/140/a club site, fuel
starvation was talked about, but no one admitted to the experience.