Coordinated turns without rudder, and autopilots

"Capt. Geoffrey Thorpe" The Sea Hawk at wow way d0t com wrote in
news:ttOdnbCk1rJ_gsPbnZ2dneKdnZydnZ2d@wideopenwest .com:

Specific enough?


Wouldn't have thought so.


Bertie

Kloudy via AviationKB.com wrote:
jesus...this is a bizarre thread.
I have never seen a troller so well fed.


EXACTLY what I was thinking - f**king unbelievable............

Mx must be exalted at his triumphant return after laying low several days
setting up his prey...

d:-))

"Capt. Geoffrey Thorpe" The Sea Hawk at wow way d0t com writes:

Your simulated autopilot in your simulated Baron appears to make
"coordinated turns" without using the simulated rudder because that's how
Microsoft wrote the software.

No, that's not it. That would require special coding. I can't imagine
writing special code just to simulate something that doesn't match real life,
when not writing the code would result in behavior that _does_ match real
life.

And the Baron I fly wasn't created by Microsoft.

george writes:

Why don't you like flying real aeroplanes?

Not having piloted a real airplane, I cannot say with certainty that I would
not like it. However, I can think of several disadvantages:

- It takes too much time to get a license.
- It costs too much to get a license.
- It's too hard to get a medical.
- Owning a real aircraft is financially unrealistic.
- Renting a real aircraft is financially unrealistic.
- Real airplanes go places, and I don't like to travel.
- Real airplanes can crash, especially small tin cans with their unreliable
components and frequently poor maintenance.
- You cannot stop a real flight if you get tired of flying.
- There is no way to control real-world weather.
- You can only fly from places you are, so you can't fly out of London for an
hour and then switch to LAX.
- The environment inside an aircraft isn't always comfortable.
- You have to worry about hypoxia at altitude.
- If the aircraft moves a lot you may become airsick.
- Real flying is limited to tiny tin cans that you can afford; transport
aircraft are out of reach unless you fly for a living.

These are just a few of the potential problems. Now, I don't know if they
would actually add up to a negative experience, but it wouldn't surprise me
given their number and magnitude.

Simulation provides many of the advantages and none of the disadvantages
(although it has some disadvantages of its own). For me it's a good
compromise. I can't speak for others. Those who dismiss it out of hand,
though, generally don't know what they are talking about.

Snowbird writes:

MSFS has for a long time been known to have a rather inaccurate flight
model. MS tends to focus on the eye candy aspects of simulation.

Which aspects are inaccurate?

In my own experience, the stall/spin entry behavior is an easily explored
area which quite clearly reveals the inadequacies of MSFS' flight modeling
as compared to the real world. And it reflects of course as well in other
areas of the flight envelope.

A coordinated turn is neither a stall nor a spin.

Years ago I flew extensively with a popular WWII networked combat airplane
simulator (Warbirds). One of its claims to fame was that its flight dynamics
model was based on actual real-time calculation of the motional differential
equations that govern the flight dynamics of an aircraft. This in contrast
to the "simplistic table-driven flight dynamics model of the mainstream PC
simulators" probably referring to MSFS.

Table-driven models are often more accurate. They don't have to calculate
anything; they just look up the data taken from the real aircraft. They don't
work in exceptional regimes of flight because the data for those in the tables
are either absent or incorrect (as the real aircraft may have never been flown
in those regimes to gather the data). But they work better than physics
calculations in normal regimes of flight because they are guaranteed to match
the real aircraft--after all, they are just reproducing what the real aircraft
did in those cases.

Physics models are better at handling all regimes of flight, since they
calculate behavior on the fly. However, they rarely match the real aircraft
precisely, because inaccuracies in the model are extremely difficult to
correct completely enough to reproduce real-world behavior in flight,
especially in real time. It's much easier to just measure the real aircraft
and put that in a table. Additionally, if you want to certify a simulation,
table-driven simulation is a lot easier to certify because it's very easy to
make the simulation match a specific real-world aircraft.

Marketing talk aside, I found that simulator MUCH more realistic in the
flight dynamics modeling than MSFS. Especially at the edges of the flight
envelope, where the differences between different airplanes were very
significant.

See above. I don't fly at the edges of the envelope--on that path lies
danger.

Viperdoc writes:

OK- one more time: I fly a real Baron with an autopilot, and I can
categorically tell you that the autopilot does not command a coordinated
turn. However, the plane itself does not have a lot of adverse yaw, and even
at a standard rate turn it only goes around half a ball into the turn on the
TC. It is not noticeable by any seat of the pants criteria.

I'm in the Baron right now. With altitude and heading hold set, the ball
moves about 3/4 out of its cage as the AP rolls into a turn, then settles at
about 1/5 of the way out of the cage during the turn. It moves about 2/3 out
of the cage as the aircraft rolls back to level flight.

If I turn off the altitude hold, the excursions are a bit worse, and the
aircraft loses 1200 feet or so in altitude during a 90-120-degree turn (from
stable flight at 3000).

This is the way a real Baron flies, and I have been in more than a few.

See above.

If you believe that your game is more accurate than a real plane with a real
pilot, you are more delusional than you appear.

If you believe the simulation is grossly inaccurate, you haven't tried the
simulation.

Unless you've flown a real Baron (or Extra) as well as played MSFS, you have
no basis of comparison.

My main handicap is that I don't know what the excursions of the ball
represent in terms of magnitude. The ball is pegged to the right and left
stops during even the gentlest turns on the taxiway, which implies that it
must be very sensitive, but since I have no sensation in this sim I try to
keep it centered, and that is not easy.

I'll have to practice turns with no rudder to see if I can meet or exceed the
performance of the AP. The simulated AP is a KFC 225, but not all AP modes
are simulated (however, this may not be correlated with the accuracy of the
modes that are simulated).

Bob Crawford writes:

How do you substantiate your initial claim that "[Real life GA]
autopilots make coordinated turns even when they cannot control the
rudder"?

By watching the ball in the turn indicator. It moves far less in an AP turn
without rudder than it moves when I make a turn without rudder. It leads me
to believe that the AP rolls the aircraft in a specific way that minimizes
uncoordinated flight. I'm trying to figure out the best way to make a turn
without rudder in a similar way, since I figure it will help make coordinated
turns _with_ the rudder.

The only proof of this supposed phenomenon you've provided is that it
occurs in MSFS.

MSFS is a simulator. If it happens in the sim, it probably happens in real
life.

Additionally you've offered no proof that MSFS models autopilot
behaviour correctly in this respect.

I have no reason to believe that it is incorrect. In fact, Viperdoc's
description of the real aircraft matches the behavior in the sim.

With that in mind, and given the statements from real life pilots that
real life autopilots do not behave as you describe the MSFS autopilot
doing ...

See above.

... a poorly modelled rudder / yaw response or AP seems like a
perfectly logical conclusion.

It's an attractive conclusion (for those who wish to disdain simulation), but
not a logical one.

"Mxsmanic" wrote in message
...

Hey, your forgot:

- I'd have to get of my lazy ass and work for a living.

"Mxsmanic" wrote in message
...


See above. I don't fly at the edges of the envelope--on that path lies
danger.

Did you fall out of your desk chair again?

"Mxsmanic" wrote in message
...

Sounds like your desk isn't level. Stick a book under one leg.