Lancair Legacy Design Flaw?

On Nov 2, 8:22*pm, Alan Baker wrote:
In article
,

*BobR wrote:
On Nov 2, 5:56*pm, Alan Baker wrote:
In article
,

*BobR wrote:

snip

snip





Oh for gawd sake, you are talking about two totally
different
designs
and the aerodynamics of the two are totally different.

In article
,
BobR wrote:

On Nov 2, 8:22*pm, Alan Baker wrote:
In article
,

*BobR wrote:
On Nov 2, 5:56*pm, Alan Baker wrote:
In article
,

*BobR wrote:

snip

snip





Oh for gawd sake, you are talking about two totally
different
designs
and the aerodynamics of the two are totally
different.
*The
Lancair
is
NOT a pusher and the engine is mounted forward of the
CG
instead
of
on
top of it. *When the engine quits it will not pitch
upward.
*The
plane
you flew had the engine well above the center of
gravity
with
a
pusher
prop and as a result produced a force that pushed the
nose of
the
aircraft down. *The two planes would not act pretty
much
the
same
at
all. *The weight of the engine on the Legacy is
forward
of
the CG
and
as a result always pulling the nose of the plane
down.
*The
counter
to
the nose down is the horizontal stabilizer and the
elevator.
*Look at
the angle of incedence on the Horizontal Stabilizer
and
you
will
find
a slight downward angle, not an upward angle as is
common
on
the
wing. *This counteracts the force from the weight of
the
engine.
*An
engine out condition will not have a significant
effect
on
pitch
until
the airspeed changes and that will result in a nose
down,
not
nose up
pull.

The one thing not quite right is that there is no
important
difference
between tractor vs. pusher configurations with respect
to
directional
stability.

Not sure what you are replying to but I never said
anything
about
directional stability. *The discussion was regarding
pitch
forces.

Which is essentially the same thing.

Pusher or puller doesn't affect pitch forces. What affects
pitch
forces
is the length of the moment arm between the centre of mass
and
the
thrust line.

Like some of the early rocket designers (e.g. Goddard),
you
are
falling
into the fallacy that somehow pulling is more stable
than
pushing.
This
is not so.

- Show quoted text -

Again Alan, I never indicated any issue with pusher vs
tractor.
*The
layout of the two planes being discussed is totally
different.
*One
involved a tractor configuration with the thrust line being
very
near
the vertical center of gravity. *The second involved an plane
with
the
engine mounted on a pylon with a thrust line well above the
vertical
center of gravity. *This configuration, rather it be a
tractor or
pusher will induce nose down forces that must be countered by
the
horizontal stabilizer with an upward force. *This is contrary
to
the
standard configuration which requires a downward force to
counter
the
weight of the engine. *The post I was replying to was trying
to
link
the characteristic of the pylon mounted configuration to the
Legacy.

Sorry, man, but you made specific reference to the plane being
a
pusher
as if it was a relevant factor:

"The Lancair is NOT a pusher and the engine is mounted forward
of
the
CG
instead of on top of it. *When the engine quits it will not
pitch
upward. *The plane you flew had the engine well above the
center of
gravity with a pusher prop and as a result produced a force
that
pushed
the nose of the aircraft down."

When you include extraneous details, you make the essence of
the
situation harder to glean.

And you're doing it again. You're conflating thrust line
induced
pitch
changes with weight of engine. One is changing, one is
constant.

The only part that you had to talk about was the fact that the
thrust
line was significantly above the centre of mass. The weight of
the
engine doesn't matter (in an aircraft that has it's centre of
gravity
appropriately located), nor does pusher vs. puller.

- Show quoted text -

Well excuse the holy hell out of me for not phrasing things the
way
you want it. *My references were based on the specifics of the
two
planes involved in the discussion and if you can't gleem that
fact
from it, too ****ing bad.

Trying to retcon your comments and say that such and such wasn't
what
you meant would work better if you...

I said what I ment but I can't help that you read into it something
else.

And you made the fact that the aircraft was a pusher an issue.

You were wrong. Deal with it.

No, I never made the fact that the aircraft was a pusher into an
issue...YOU DID. *I simply pointed out different design elements of
the two aircraft. *You drew false conclusions from them and now try to
make a issue from them.

Sigh....

"The Lancair is NOT a pusher..."


AND THAT IS WHERE YOU MIND WENT BLANK AND YOU STOPPED COMPREHENDING
ANYTHING ELSE.

Nope.

I comprehended the rest fine.

You, OTOH, led of your reply with what you now claim was an
irrelevancy...




...ACTUALLY SHOWED YOU UNDERSTOOD WHAT YOU'RE TALKING ABOUT...

I knew exactly what I was talking about but again, you read something
into it beyond what I said. *That part is your problem not mine.

Nope. Because the weight of an engine has precisely the same influence
on the aircraft at all times, operating or not.

Gee do tell! *Again you make false assumptions and then try and make
some point from it.

Sigh...

"This is contrary to the standard configuration which requires a
downward force to counter the weight of the engine."

That's you attributing the engine's weight some special status when in
the nose, when if fact, it is the overall position of the centre of
gravity that matters.


Yep, the fact that it is FORWARD of the CG doesn't matter at all.
Damn but you can't seem to understand anything that is not said
exactly like you want it to be. Take one part out of context and try
and make an entire argument from it.

Precisely correct. The fact that it is forward of the centre of *mass*
doesn't matter at all, because whatever the location of the engine, its
effect is the same whether its operating or not.



...in your next post.

You, OTOH, showed you still didn't get it and now you're getting
****y.

I am getting very tired of your arrogant attitude that ONLY YOU
understand.

Not "only me", just -- quite obviously -- not you.

And the word your tiny little mind was scratching for was "glean".

Sorry but my typing isn't always the greatest and once again, your
arrogance shows in thinking you are the only smart one in the group.

Sorry, (and note the correct use of the comma, BTW) but the error
wasn't
a typo, and you can't retcon it into one.

Yep, once again your arrogance rises to the occasion.

My ability to understand that typing "gleem" when the word you're
looking for is "glean" can't be a typo is "arrogance", now?


So I didn't spell the word correctly...big fking deal. You want to be
my english teacher now too? The arrogance is that you couldn't help
yourself and had to make an issue of that too.

But you didn't claim it was a spelling error. You claimed it was a
typo...



Always happy to help the ignorant.

Gee, so nice of you to come down from that tower you put yourself
into
and mingle with us common folk.

Hey...

You're more common than most.

And you are a lot more arrogant than most. *Looking back through your
posts it was clear that you felt the necessity to correct just about
everyone. *Guess that puts me in the good company of a lot of other
common folk.

I correct things that are incorrect. Unlike you: who introduces
extraneous and erroneous points into a discussion, thus clouding the
issue.


No, you make issues where there were no issues and your arrogance
doesn't allow any one else room to say anything. You had to pick
apart my response without even trying to understand the point I was
trying to get across. You still don't get it and never will. You did
the same to everyone else who responded as well.

Sorry, but no. You make issues out of hwat (BTW, *that* is what a typo
looks like) are not issues.


The only thing that matter was thrust line. You kept introducing other
factors that were irrelevant.


That was clearly the only thing YOU BELIEVED mattered and clearly I
didn't say it exactly the way you wanted. TOO BAD! Yes, in this
particular case, the thrust line was important and I indicated such
but not in those words. But what I was more interested in was
pointing out that the two planes had totally different configurations
and would react differently. You can't and will never accept that
because you can't get beyond your own intrepretations an insist on
talking down to everybody.

The thrust line was *all* that was important in this discussion. And
clearly, you still don't understand that.

The only difference in their configuration that matter in the case of
loss of engine power was where the thrust line was in relation to the
centre of mass. The whole pusher/puller and position of the engine's
weight were completely irrelevant.

Simple fact, and I'm sorry you can't get it.


So at this point, I will simply yield to your superior knowledge of
all things and say that you are always right. From this point on I
will not try to make any posts unless you proof read them first. I
will also encourage everyone else to do the same.

Great. The group will be better off for it.

--
Alan Baker
Vancouver, British Columbia
http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg