Overweight takeoff / flight

"Greg Esres" wrote in message
news
Then you haven't read Part 23.

Yes, I have.

Let me point out the sections to you:

Those sections stipulate, given an existing Va, how the control surfaces
must be designed. They do not in any way define Va.

The point is that at Part 23 doesn't require this. And not all
aircraft publish such variations.

You are still hung up thinking that Part 23 is what makes airplanes fly.

Again, you didn't read what I wrote. I said it doesn't scale UP.
Flying over max gross may increase maneuvering speed, but it doesn't
increase VA, because the increased weight won't protect control
surfaces from failure.

In this context "maneuvering speed" is synonymous with "Va". Yes, you're
right, there is only ONE Va. But in the world of piloting, we commonly
understand the shorthand "Va" to mean "maneuvering speed at a given aircraft
weight" where the weight is changeable.

Tangent? It's the essence of what Va is.

Not in this context it's not.

I seriously doubt Todd has told you that Va remains the same
regardless of aircraft weight. You obviously misunderstood him.

Ok, you read what he wrote and tell me:

If you think that he was explaining the aerodynamics of maneuvering speed,
you misunderstood him. If you don't think that he was explaining the
aerodynamics of maneuvering speed, then your comments based on that quote
are irrelevant to this thread.

Pete

"Tony Cox" wrote in message
hlink.net...
Greg is right. They really ought to have invented
another term for it.

That's not what Greg said.

I don't see why a whole thread that is really about aerodynamics needs to be
co-opted by the terminology police. The original question was clear enough
in its intent. The OP isn't asking about how to meet FAA certification
standards. He's asking about over-gross operations and their effect on
airplane performance.

Pete

"Peter Duniho" wrote in message
...
"Tony Cox" wrote in message
hlink.net...
Greg is right. They really ought to have invented
another term for it.

That's not what Greg said.

I don't see why a whole thread that is really about aerodynamics needs to
be
co-opted by the terminology police. The original question was clear
enough
in its intent. The OP isn't asking about how to meet FAA certification
standards. He's asking about over-gross operations and their effect on
airplane performance.

Pete


Well, I'm certainly not the terminology police, and I'm
awfully reluctant to get confrontational, especially with
the holidays about to start.

But there is an important point here, and one that I'd
not appreciated before this discussion. The fact is that
under pt 23, the often-quoted Va speed isn't in fact
the speed at which you can apply full control deflection
without risk of structural failure. Va is determined by
control constraints, and by the requirement that it must
be = Vs*sqrt(n). This means that it is quite possible
(although, I'd proffer, unlikely) for the POH value of
Va to be above the value where you'd risk exceeding
the load factor.

I think this is an important safety point, unappreciated
by many (and until just recently, by me too).

Cheers & happy holidays.

--
Dr. Tony Cox
Citrus Controls Inc.
e-mail:
http://CitrusControls.com/

we commonly understand the shorthand "Va" to mean "maneuvering speed
at a given aircraft weight" where the weight is changeable.

Then what is commonly understood is not correct, because that's not
how Va is *necessarily* determined.

Not in this context it's not.

PARTICULARLY in this context. The control surfaces were designed with
withstand full movements at PUBLISHED Va, not his new, derived, HIGHER
Va.

TC: Greg is right. They really ought to have invented another term
for it.

PD: That's not what Greg said.

GE: Greg said exactly that. He said "They really should have called
it something else, IMO."

co-opted by the terminology police.

No communication takes place without an agreed-upon vocabulary, which
is why technical disciplines define terms very precisely.

Equating "Va" to "maneuvering speed" is commonly done, but it's
sloppy. You can scale both speeds down with weight, but you can't
scale Va up.

Michael,

In Alaska, Part 135 operators can
get the max gross raised by up to 15%, depending on the airplane.

Do you have a reference for this?

I've chased it a couple of times but can't find it (I'm assuming I'm
looking in the wrong places); all I've found is for an increase for a
few very old Dept of Commerce or CAA certified airplanes such as
Stinson Trimotors and so forth, nothing modern. If you've got a
reference, I'd appreciate it.

All the best,
Rick

I began wondering
about the effects of an overweight takeoff within C.G. limits.

This is impossible. As soon as you go over gross you are out of CofG by
definition.
Paul

"Greg Esres" wrote in message
...
PARTICULARLY in this context. The control surfaces were designed with
withstand full movements at PUBLISHED Va, not his new, derived, HIGHER
Va.

There are any number of structural issues raised by overgross flight. It
was clear to me which one he was asking about, and the control surfaces
ain't it.

"Paul Cook" wrote in message
...
I began wondering
about the effects of an overweight takeoff within C.G. limits.

This is impossible. As soon as you go over gross you are out of CofG by
definition.

I guess that depends on how you define "out of CofG". I define it as not
within the fore and aft limits for the position of the center of gravity.
Under that definition, you certainly can still be within those limits while
being above the maximum gross weight.

I prefer to use the term "out of weight & balance limits" as the general
term for being overweight or out of the CG limits or both. Though, if only
overweight or out of CG limits, I'd actually prefer to just use the term
that actually describes the condition.

Pete

"Paul Cook" wrote:

This is impossible. As soon as you go over gross you are out of CofG by
definition.
Paul

Actually not by definition. CofG (Centre of Gravity) is the balance
part of weight and balance. It is measured in distance from a datum.
There are no weight units in CG.