Mechanics of Elevator Trim. In Detail.

Le Chaud Lapin wrote:

MSFS was the means by which I discovered the mechanism.

If I had learned in actual aircraft, the question still would have
been relevant.

-Le Chaud Lapin-



You never learned of trim until MSFS and you are going to design an
airplane. Fabulous!

On Jun 9, 1:19*pm, Gig 601Xl Builder
wrote:
Le Chaud Lapin wrote:
MSFS was the means by which I discovered the mechanism.

If I had learned in actual aircraft, the question still would have
been relevant.

-Le Chaud Lapin-

You never learned of trim until MSFS and you are going to design an
airplane. Fabulous!

Is it really necessary to understand the particular way it was done in
C172 to achieve the same result?

The same thing could be achieved using more electronics, less
mechanics, and the controls might be entirely different.

-Le Chaud Lapin-

Le Chaud Lapin wrote:
On Jun 9, 1:19 pm, Gig 601Xl Builder
wrote:
Le Chaud Lapin wrote:
MSFS was the means by which I discovered the mechanism.
If I had learned in actual aircraft, the question still would have
been relevant.
-Le Chaud Lapin-
You never learned of trim until MSFS and you are going to design an
airplane. Fabulous!

Is it really necessary to understand the particular way it was done in
C172 to achieve the same result?

The same thing could be achieved using more electronics, less
mechanics, and the controls might be entirely different.

-Le Chaud Lapin-

Not knowing about trim by someone who thinks they are going to design an
airplane is like someone who wants to be an electrician and doesn't
understand the difference in AC and DC.

It's just another example that you have no business trying to design an
aircraft.

On Jun 9, 3:30*pm, Gig 601Xl Builder
wrote:
Not knowing about trim by someone who thinks they are going to design an
airplane is like someone who wants to be an electrician and doesn't
understand the difference in AC and DC.

It's just another example that you have no business trying to design an
aircraft.

This is a false analogy.

It depends on what is meant by "knowing about trim". The purpose of
trim is clear, and the objective of trim can be achieved in many
ways.

It is not necessary to know all the ways that the objective of trim
can be achieved in order to implement just one mechanism that achieves
the objective.

-Le Chaud Lapin-

On Jun 9, 12:36 pm, Le Chaud Lapin wrote:
On Jun 9, 1:19 pm, Gig 601Xl Builder

You never learned of trim until MSFS and you are going to design an
airplane. Fabulous!

Is it really necessary to understand the particular way it was done in
C172 to achieve the same result?

The same thing could be achieved using more electronics, less
mechanics, and the controls might be entirely different.


#1. Learn to fly first.
#2. Study the construction of aircraft, best done by taking an
aircraft maintenance course.
#3. THEN think about designing an airplane. No worthwhile design that
I'm aware of has ever been put forward by someone who was unfamiliar
with the way things are now and why they are that way, but I have seen
designs built by folks who "knew better" than everyone else. One of
those, built by a local guy who would take no constructive criticism
of his ideas, stalled at circuit altitude and dropped him, hard, on
the surface of the earth. He was such a stubborn guy that he got up
and walked away, but he neither built nor flew any more airplanes.
Needless to say, this design was neither inspected nor approved nor
licensed to any standard whatever.
Adding electronic controls to something like a trim tab on a
lightplane is one of those "better" ideas that has no basis in
reality. It adds complexity, which adds failure points and cost and
weight, none of which are welcome. It is no more accurate than manual
trim.

Dan

On Jun 15, 1:30 pm, wrote:
On Jun 9, 12:36 pm, Le Chaud Lapin wrote:

On Jun 9, 1:19 pm, Gig 601Xl Builder
You never learned of trim until MSFS and you are going to design an
airplane. Fabulous!

Is it really necessary to understand the particular way it was done in
C172 to achieve the same result?

The same thing could be achieved using more electronics, less
mechanics, and the controls might be entirely different.

#1. Learn to fly first.
#2. Study the construction of aircraft, best done by taking an
aircraft maintenance course.
#3. THEN think about designing an airplane. No worthwhile design that
I'm aware of has ever been put forward by someone who was unfamiliar
with the way things are now and why they are that way, but I have seen
designs built by folks who "knew better" than everyone else. One of
those, built by a local guy who would take no constructive criticism
of his ideas, stalled at circuit altitude and dropped him, hard, on
the surface of the earth. He was such a stubborn guy that he got up
and walked away, but he neither built nor flew any more airplanes.
Needless to say, this design was neither inspected nor approved nor
licensed to any standard whatever.
Adding electronic controls to something like a trim tab on a
lightplane is one of those "better" ideas that has no basis in
reality. It adds complexity, which adds failure points and cost and
weight, none of which are welcome. It is no more accurate than manual
trim.
Dan

I concur with Dan on his last two posts, yeah that's
rare, but anyway...
I designed and tested (models) of a fantastic plane,
but when I chose between putting my wife and kids
in my fantastic plane or into a proven (safe) C172,
I chose the C172.
Here's why: If my machine cracked up due to a fault
in my design, and killed my family except for me, I'd
feel obligated to shoot myself, though I wouldn't.

That said, build your machine, put it threw it's paces
then take on a passenger, who knows what the tag
"EXPERMENTAL" means on the side of the A/C,
and have fun.
Ken

On Jun 15, 6:34*pm, "Ken S. Tucker" wrote:
I concur with Dan on his last two posts, yeah that's
rare, but anyway...
I designed and tested (models) of a fantastic plane,
but when I chose between putting my wife and kids
in my fantastic plane or into a proven (safe) C172,
I chose the C172.
Here's why: If my machine cracked up due to a fault
in my design, and killed my family except for me, I'd
feel obligated to shoot myself, though I wouldn't.

That said, build your machine, put it threw it's paces
then take on a passenger, who knows what the tag
"EXPERMENTAL" means on the side of the A/C,
and have fun.
Ken-

Perhaps there will not be time in my life to see a design realized,
but if I were so fortunate, I would probably do just that...get in it
myself first.

But before doing that, I would let it fly itself over a desert, since
controls would be software anyway.

-Le Chaud Lapin-

On Jun 15, 9:16 pm, Le Chaud Lapin wrote:
On Jun 15, 6:34 pm, "Ken S. Tucker" wrote:

I concur with Dan on his last two posts, yeah that's
rare, but anyway...
I designed and tested (models) of a fantastic plane,
but when I chose between putting my wife and kids
in my fantastic plane or into a proven (safe) C172,
I chose the C172.
Here's why: If my machine cracked up due to a fault
in my design, and killed my family except for me, I'd
feel obligated to shoot myself, though I wouldn't.

That said, build your machine, put it threw it's paces
then take on a passenger, who knows what the tag
"EXPERMENTAL" means on the side of the A/C,
and have fun.
Ken-

Perhaps there will not be time in my life to see a design realized,
but if I were so fortunate, I would probably do just that...get in it
myself first.
But before doing that, I would let it fly itself over a desert, since
controls would be software anyway.

That sounds like a good idea.
A 1/4 scale is good, it can be powered by a cheap
chainsaw motor.
Do you have any general ideas for a lay-out yet?

-Le Chaud Lapin-

If you lived close by, I'd give you some help.
Ken

On Jun 16, 10:08*am, "Ken S. Tucker" wrote:
On Jun 15, 9:16 pm, Le Chaud Lapin wrote:





On Jun 15, 6:34 pm, "Ken S. Tucker" wrote:

I concur with Dan on his last two posts, yeah that's
rare, but anyway...
I designed and tested (models) of a fantastic plane,
but when I chose between putting my wife and kids
in my fantastic plane or into a proven (safe) C172,
I chose the C172.
Here's why: If my machine cracked up due to a fault
in my design, and killed my family except for me, I'd
feel obligated to shoot myself, though I wouldn't.

That said, build your machine, put it threw it's paces
then take on a passenger, who knows what the tag
"EXPERMENTAL" means on the side of the A/C,
and have fun.
Ken-

Perhaps there will not be time in my life to see a design realized,
but if I were so fortunate, I would probably do just that...get in it
myself first.
But before doing that, I would let it fly itself over a desert, since
controls would be software anyway.

That sounds like a good idea.
A 1/4 scale is good, it can be powered by a cheap
chainsaw motor.
Do you have any general ideas for a lay-out yet?

-Le Chaud Lapin-

If you lived close by, I'd give you some help.

I live in Austin, Texas.

Some locals and I have been toying around with the idea of renting a
garage for experiments, though I think that is premature. I would
rather use something like SolidWorks to create a model to verify that
the aircraft would fly first. I do have a vague vision of the form-
factor of the aircraft, but as I see it, there are two crucial things
that need to be determined before putting both feet in the water:

1. The PAV I envision relies on an unproven, unorthodox hypothesis of
the origin of lift. I say concept because there is no weird science
involved like anti-gravity machines or anything like that, but if it
were to fly, it would require a reaxmination of the prevailing
theories. This is the hardest part, and I have been concentrating
only on the lift elements. A lot of math and a prototype of certain
control surfaces would help.

2. The second problem is a problem that would be faced by any designer
of a PAV, and that is the power source. The PAV I envision would have
an extremely high reliance on electrial power (the lift engine itself
would rely on electrical power), and this is a hard problem.
Conventional fuels, in 2008, still appear to be the most pratical
approach, even if the fuel is only used to operate a generator.

As far as the engine, I cannot say what it is yet, but can say that it
doesn't use an ICE.

-Le Chaud Lapin-

On Jun 15, 3:30*pm, wrote:
On Jun 9, 12:36 pm, Le Chaud Lapin wrote:

On Jun 9, 1:19 pm, Gig 601Xl Builder
You never learned of trim until MSFS and you are going to design an
airplane. Fabulous!

Is it really necessary to understand the particular way it was done in
C172 to achieve the same result?

The same thing could be achieved using more electronics, less
mechanics, and the controls might be entirely different.

#1. Learn to fly first.
#2. Study the construction of aircraft, best done by taking an
aircraft maintenance course.

I think the difference here is that I am not looking for something
evolutionary. I think that is a dead-end road. There is so much in
the world to learn, that if a researcher were to take this approach to
every attempt to advance a field, breakthroughs would hardly occur. In
fact, I think it is precisely this mentality that makes the current
process not as fruitful as it could be.

Perhaps the epitome of this type of thinking can be seen on the first
page of this site: http://www.roadabletimes.com/

Question: "How does one make a flying car?"
Answer: "One could start by taking a car and putting wings on it."

This is silly, and it is obvious to everyone now that it is silly, but
to at least one individual, it was not. That man spent countless
hours purusing a dream that would never materialize because his
approach was fundamentally flawed.

Now if one were to take the objectives of CAFE/PAV to make a new type
of vehicle:

http://www.cafefoundation.org/v2/pav_home.php

..and begin by starting with a "reference" design, that person might
share the same fate of he who made the "flying car" of the first link.

Some of you think it is foolish to embark upon a research path without
having a thorough understanding of what has been done. I think not. I
think, in many cases, one can be too familiar with what has been
done. Common knowledge does not necessarily liberate the mind. It
might stifle it. And if it seems arrogant not to follow the path
already tread by great designers, I think it would be even more
arrogant, after having studied what the great designers have done, to
think that one would make extraordinary advancements beyond what those
greats have done, within the same path.

True breakthroughs often require a breach of continuity, and
significant technological advancement occurs when those breaches occur
at semi-regular intervals.

A good example is vacuum tubes versus transistors.

Absolutely zero knowledge of vacuum tubes is required to understand
transistors. There is a bit of ancillary knowledge, like
thermodynamics, band-theory, and electrodynamics that is immediately
transferrable from vacuum tube theory to transitor theory, but
knowlege of vacuum tubes themselves is inessential.

But both act as amplifiers. Both essentially accomplish the same
thing as elements in a larger system.

Now imagine, toward the end of the vacuum tube era, that someone had
proposed to make a new type of amplifier that would be better on
almost every imaginable axes, but that person had no intention of
spending any time studying vacuum tubes. Would it have been necessary
to study vacuum tubes?

This is essentially what you are saying about PAV's. You are saying
that, the best way to proceed is to learn all I can about convential
aircraft. Why is that necessary? It presumes that the method by which
the objective is accomplish is similar to what has already been done
(tractor model, for example).

A better approach might be to make no assumptions at all, but focus on
the end result, then work backward, evaluating extant technologies
(applicable in, say, 2010), keeping a respectible distance from the
prevaling models of aicraft design, just as transitor theorist might
deliberately keep a respectable distance from vacuum tubes.

#3. THEN think about designing an airplane. No worthwhile design that
I'm aware of has ever been put forward by someone who was unfamiliar
with the way things are now and why they are that way, but I have seen
designs built by folks who "knew better" than everyone else. One of
those, built by a local guy who would take no constructive criticism
of his ideas, stalled at circuit altitude and dropped him, hard, on
the surface of the earth. He was such a stubborn guy that he got up
and walked away, but he neither built nor flew any more airplanes.
Needless to say, this design was neither inspected nor approved nor
licensed to any standard whatever.

A good way to win is avoid races where number of entrants is 1. It
would be extremely hard for someone in my opinion to make notable
improvement on existing aircraft design. The world is filled with high
skilled, highly trained, thoroughly experience, professional aircraft
designers who spent their lifetimes aiming for that extra 5%.

Extra 5% is not going to make a PAV, so if there is any chance of
succeeding at all, one should avoid paths where best-case scenario is
a 5% improvement.

* * * * *Adding electronic controls to something like a trim tab on a
lightplane is one of those "better" ideas that has no basis in
reality. It adds complexity, which adds failure points and cost and
weight, none of which are welcome.

I hear a lot of mechanics say this about cars. I think there should
be a qualification made thos these types of statments:

"It adds complexity, which adds failure points and cost and weight,
none of which are welcome, unless the person integrating the
electronics is an electrical engineer unperturbed by the idea of
adding electronic controls to a mechanical system."

It is no more accurate than manual
trim.

Perhaps not. But a computer will outperform a human 10x to 1x if the
goal is to optimize fuel consumption with automatic trim control.
There is literally countless scenarios where combination of software/
electronics would far exceed capabilities of a pilot to achieve same
objective.

As aviation advances, there will be much more employment of
electronics and software.

I am simply saying, whatever will exist 50 years from now (when many
of us will be dead, heheh)...whatever that thing is...start thinking
about *that* now, not something that was designed in 1950.

-Le Chaud Lapin-