Flap angles

The effect of slips with full flaps on some high wing Cessnas is on
the elevators, not the rudders. As a result, there's no real
difference for that maneuver between the straight and swept tail. If
there is a difference it's with the airplanes that have rear windows
versus the earlier ones that don't, due to the flow of the downwash
off of the flaps over the rear fuselage. Because the downwash may not
be consistent on the elevators as the airflow changes during the slip
it is suggested, not required, on some Cessnas, that slips be avoided
with full flaps. There is no such suggestion on models such as the
Cardinal. Even at its worst, the downwash change as the slip changes
only causes a very mild pulse in the control wheel that you feel as a
tug. It's a nonevent, but pilots who haven't experienced it before
can get excited because it is new.

BTW, there is absolutely no aerodynamic difference between a forward
and side slip. The difference is relative to track across the ground
once wind comes into play. The airplane is doing the same thing
aerodynamically no matter what sort of ground track is desired.

All the best,
Rick

zatatime wrote in message . ..
On Sun, 16 May 2004 19:16:16 -0400, "John Gaquin"
wrote:


"zatatime" wrote in message

Thank you for this information! .... One of my biggest pet peeves
are CFIs who actually teach people to slip a 172 with flaps.


???????

Did you read what Cpt Moore posted?

Completely. Depending on the model you will have different flight
characteristics while performing a forward slip. I doubt very
seriously that a typical flight instructor will have an in depth
conversation on models made in '72 and later, vs a straight tail, vs
everything in between (hell many don't even bother to make sure a
student knows the difference between a forward slip and a side slip)
so I would err on the side of caution and advise against teaching
slips as a general rule in 172 / 182s.

z

Bob Moore wrote:
Dave S wrote
The aircraft doesnt distinguish between a forward and a side slip, so
why should the CFI?
Probably because the FAA makes the distinction in AC 61-21A Flight
Training Handbook (pages 102-103). I don't have the replacement
for that AC, but it's probably in there also. I can assure you that
an Examiner will expect a CFI to have instructed the student on the
difference.

There is no way to slip other than sideways.
CV

My experience was with 40 degrees of flaps and a full forward slip (at
altitude), the aircraft pitched abruptly downward (like a chain was
connected from the ground to the nosewheel). Not only was it very
uncomfortable, but it taught me a valuable lesson about the aircraft.
I was in a '62 or '63.

Your post and the fact that you have learned this from "many
instructors" re-enforces my ideology.

I honestly hope you never experience this at low altitude.

z

On Mon, 17 May 2004 03:24:05 GMT, Dave S
wrote:

A great way to descend quickly in a 172 is full flaps, cross controls
into a slip, and descend at the top of the white arc. Learned it from
more than one CFI. I personally have yet to observe the pitching
phenomenon described, but I have been aware of it's existence for years.

Dave

zatatime wrote:

On Sun, 16 May 2004 19:16:16 -0400, "John Gaquin"
wrote:


"zatatime" wrote in message

Thank you for this information! .... One of my biggest pet peeves
are CFIs who actually teach people to slip a 172 with flaps.


???????

Did you read what Cpt Moore posted?


Completely. Depending on the model you will have different flight
characteristics while performing a forward slip. I doubt very
seriously that a typical flight instructor will have an in depth
conversation on models made in '72 and later, vs a straight tail, vs
everything in between (hell many don't even bother to make sure a
student knows the difference between a forward slip and a side slip)
so I would err on the side of caution and advise against teaching
slips as a general rule in 172 / 182s.

z

On Mon, 17 May 2004 13:56:35 GMT, Bob Moore
wrote:

EDR wrote

"Yeah, Bill Thompson sometimes got a little sensational to sell his
books. sigh"

That's a potentially litiguous statement for a barrister, isn't it
Rick? I think you owes us a more complete explaination.
You have opened the door on this topic, now walk us through it.

First, let me say that I know neither Mr. Thompson nor Mr. Durden. I
find on web sources that Mr. Durden worked for the Cessna Aircraft
Company in their legal department for about eight years. Mr. Durden is
also the holder of numerous airman certificates including an ATP.

I post the following from the back cover of Mr. Thompson's book.

"The author learned to fly in college in gliders and airplanes in 1940,
and continued his advanced flight training in St. Louis while working
for Curtiss-Wright Airplane Company until 1942. In the war emergency he
trained Army Air Corps and French Cadets for a Civilian Contract School
in South Carolina. Returning to Purdue University in 1945 and switching
to an aeronautical engineering curriculum, he graduated in February,
1947. For the next 28-years, he worked for Cessna Aircraft Company as an
engineering test pilot and, later, as the Manager of Flight Test &
Aerodynamics. He is a Fellow in the Society of Experimental Test
Pi-lots, and at Cessna was a long-time member of the SAE Cockpit
Standardization Committee and the sole representative of the General
Aviation Industry on NASA's Aerodynamics/Aeronautics Committees.
Presently, he owns Thompson Aeronautical Consultants and is an FAA
Engineering Representative for flight test pilot/analyst assignments."


I now ask myself.....self, who has the most credibility when it comes to
discussing the aerodynamic effects of various flap settings on a Cessna
172 airplane? :-)

Bob Moore

Well it certainly can't be Mr. Thompson.....All those credentials
can't compare to the training most people get at the local 141 school
can they?

-Tongue planted firmly in cheek.

z

Roger Halstead wrote in message

(Snipped)
If you are referring to the May issue (we don't all receive our issues
at the same time) then no it doesn't.

It does have one by Tom Benneson though on page 84.

There's a lot in that article to which I take issue.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Mr. Halstead,

The article to which I was referring to is entitled "The Grand Arrival
Takes Time" on page 56 of the June 2004 issue of Flying . It was
written by Richard Collins.

I don't remember reading the article you refer to and I have already
given my copy of the May issue away to a friend.

When you get the June issue, read the article. It would be
interesting to know what you think.

Blue Skies

John Pelchat