On 3/30/2015 6:48 PM, Mr. Luddite wrote:
On 3/30/2015 6:20 PM, Califbill wrote:
"Mr. Luddite" wrote:
On 3/30/2015 10:47 AM, John H. wrote:
On Mon, 30 Mar 2015 10:20:47 -0400, "Mr. Luddite"
wrote:

On 3/30/2015 9:57 AM, John H. wrote:
On Mon, 30 Mar 2015 04:57:56 -0700 (PDT), True North
wrote:

Keyser Söze
- show quoted text -
"So, this is what you have to contend with when flying that RC
Cessna 172?

http://tinyurl.com/pvyg9t7 "


SNERK!
Is Johnny still trying to convince everyone that flying his toy is
the same as flying a real plane?

Don, can you find where anyone here has said any such thing?



I don't think you ever claimed that flying a RC is the same as
flying a
real plane. Of course it isn't.

Exactly.


At some point in the discussion you asked what the "differences" are.

I don't believe that's true either. I believe I may have referred to
'similarities'
in which case you started in about how they were not at all similar.

Among the obvious (being what happens to the "pilot" and airplane if
he/she screws up) one of the differences is in how some are
"steered" at
slow speeds on the ground. My comments where related to the types of
airplanes that I had experience flying ... primarily the high wing,
tricycle gear small Cessnas.

You asked perhaps a dozen different questions. To each of them I
provided an answer.
You then highlighted the 'big differences', such as the steering,
which in fact
turned out to be quite similar in both real and RC aircraft. In
fact, a whole lot of
similarities surfaced.

You claim that they have a steerable nose gear, controlled by the
rudder
pedals. I claim they have a passive, spring loaded nose gear
that allows it to "follow" a turn but does not initiate the turn.
The "steering shafts" that you refer to are the two, spring loaded
assemblies that allow limited angle movement of the nose gear to
follow
the turn. A sharp turn is initiated by differential braking.
Shallow or
wide turns can be accomplished by deflecting the rudder (with the
rudder
pedals that will cause the prop wash to push the tail one way
or another. The nose gear simply follows (slightly) due to
compression
on one of the springs in the assemblies. Otherwise, you'd be scuffing
the nose gear tire similar to making a sharp turn on dry pavement in
your truck with 4 wheel drive engaged.



Exactly. I'm glad to see you acknowledge that the Cessnas *can* be
turned by nose
wheel with the rudder pedals. Initially your claim was that they
couldn't, and there
was another of the big differences between 'real' and 'RC'.


On that point we are still in disagreement. The Cessnas in discussion
are *not* turned by the nose wheel. The nose wheel simply reacts to a
turn via compression of the springs in the shaft that makes a minor
adjustment in the wheel's castor angle, allowing it to follow the turn.
The turn is initiated by differential braking (for a sharp turn) or
by the affect of prop wash over the rudder. The nose gear reacts
passively.

Obviously there are other types of small airplanes that have active nose
gear steering, but this is how the Cessnas work.

Perhaps you interpret the name "steering shaft" as meaning it is active.
What is called the steering shaft is really just the tube assembly
containing the spring.

I learned something I didn't know before in this discussion. When a
Cessna lifts off on takeoff, the nose wheel drops a bit, disengaging
from
the spring loaded tubes and defaults to a position that is in alignment
with the main landing gear. This is important when landing
obviously. You hold off putting the nose down for as long as possible
while bleeding off speed.

The problem is you can not steer with the rudder at very slow speeds.
Not
enough air flow. Is why big and not so big jetliners have steering wheel
in the cockpit. 707 had it by the pilots leg. Have an hour in Western
Airlines simulator.


I think you may have missed some of the discussion.
Of course big, heavy jets can't steer using rudder only.
The exhaust of the engines is not flowing over the rudder.

Small, single engined aircraft like a Cessna *can* be steered
with the rudder even though the ground speed doesn't produce any
significant airflow. It relies on the prop wash that is in-line
with the rudder. When you deflect the rudder to one side, the prop
wash pushes the tail of the airplane in the opposite direction
of the desired turn. The result is the front of the aircraft
turns in the desired direction. It's not a quick turn and you
have to apply some additional throttle.
For sharp turns you use differential braking (like a tank).




Should have said, "big, heavy jets can't steer at taxiing speeds on the
ground" using rudder only".