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white lightning



 
 
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  #11  
Old July 9th 03, 08:23 AM
Jay
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Posts: n/a
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Depending on the amount of leg room you allow and how much the seat is
reclined, I got about 3 feet difference in passenger CG. And I'm not
counting the kind of seating where the guy in back's legs go around
the guy in front's seat (Soneri?).

At take off and landing the backwards seat could be a little wierd,
but at cruise altitude, you can hardly tell the difference. Flown
backwards several times on commercial jets and didn't even notice once
we were airborne.

(Bob Kuykendall) wrote in message
. com...
Earlier,
(Jay) wrote:

Noticed White Lightning used the same back to
back seating I've been playing with for my
concept design...
Seemed like the only reasonable way to handle
the CG for a wing with a relatively high aspect.


Actually, John Roncz explored back-to-back seating for a design that
he was doing. But he abandoned that plan after discovering that it
made only a very small difference in the CG of the seated occupant. I
think that he weighed that small advantage against the discomfort that
many potential passengers expressed with traveling backwards.

I think that this episode is described in a series of articles that he
published in Sport Aviation in 1990. According to this, I think it was
in either the May 1990 or the February 1991 article:

http://www.cozybuilders.org/ref_info/sportavi90.html

Thanks, and best regards to all

Bob K.

  #12  
Old July 9th 03, 05:54 PM
Bob Kuykendall
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Earlier, Jay wrote:

...Depending on the amount of leg room you
allow and how much the seat is reclined,
I got about 3 feet difference in passenger
CG...


Interesting. Roncz got only a couple of inches difference. That's why
he didn't bother.

Bob K.
http://www.hpaircraft.com
  #13  
Old July 9th 03, 08:58 PM
DJFawcett26
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Posts: n/a
Default

...Depending on the amount of leg room you
allow and how much the seat is reclined,
I got about 3 feet difference in passenger
CG...


If there is a 3 ft. shift in cg with passenger mass, I suspect either your
calculations, the mass distribution analysis, or the wing placement is wrong.

Cg shifts are predicated on the overall mass distribution. If a passenger can
shift the cg 3 ft., something is wrong, especially on a two place airplane (I
am assuming this is the airplane that was on the linked website).
  #14  
Old July 9th 03, 10:29 PM
Rick Pellicciotti
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Default

This can't be right. If you stop and think about it, the most the CG could
move would be the distance that the center of mass of the passenger changed.
Maybe a foot at most.

rick

"Jay" wrote in message
om...
Depending on the amount of leg room you allow and how much the seat is
reclined, I got about 3 feet difference in passenger CG. And I'm not
counting the kind of seating where the guy in back's legs go around
the guy in front's seat (Soneri?).

At take off and landing the backwards seat could be a little wierd,
but at cruise altitude, you can hardly tell the difference. Flown
backwards several times on commercial jets and didn't even notice once
we were airborne.

(Bob Kuykendall) wrote in message
. com...
Earlier,
(Jay) wrote:

Noticed White Lightning used the same back to
back seating I've been playing with for my
concept design...
Seemed like the only reasonable way to handle
the CG for a wing with a relatively high aspect.


Actually, John Roncz explored back-to-back seating for a design that
he was doing. But he abandoned that plan after discovering that it
made only a very small difference in the CG of the seated occupant. I
think that he weighed that small advantage against the discomfort that
many potential passengers expressed with traveling backwards.

I think that this episode is described in a series of articles that he
published in Sport Aviation in 1990. According to this, I think it was
in either the May 1990 or the February 1991 article:

http://www.cozybuilders.org/ref_info/sportavi90.html

Thanks, and best regards to all

Bob K.



  #15  
Old July 9th 03, 10:52 PM
Model Flyer
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Posts: n/a
Default


"wmbjk" wrote in message
...

"Fitzair4" wrote in message
...

We named it Nick's White Lead Airplane. We built up 3 fuselages

and
many parts
back in the 1980's for Nick. It was just over built.


The canopies in particular needed to be extra heavy so they'd stay

shut
without latches. ;-)


Yeh, I get that one.
Lol
--

..
--
Cheers,
Jonathan Lowe
modelflyer at antispam dot net

Antispam trap in place



Wayne




  #16  
Old July 10th 03, 11:28 AM
Robert Bonomi
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Posts: n/a
Default

In article ,
DJFawcett26 wrote:
...Depending on the amount of leg room you
allow and how much the seat is reclined,
I got about 3 feet difference in passenger
CG...


If there is a 3 ft. shift in cg with passenger mass, I suspect either your
calculations, the mass distribution analysis, or the wing placement is wrong.

Cg shifts are predicated on the overall mass distribution. If a passenger can
shift the cg 3 ft., something is wrong, especially on a two place airplane (I
am assuming this is the airplane that was on the linked website).


READING LESSON:
He said a 3 ft difference in the *passenger*cg*.
i.e. the length of the moment arm assigned to the weight of the PASSENGER.

It will have a _far_smaller_ effect on the AIRCRAFT c/g.

  #17  
Old July 10th 03, 08:46 PM
Jay
external usenet poster
 
Posts: n/a
Default

Thats exactly the distance I was referring to, the distance between
the center of mass of the passenger for the 2 different seat
positions.

As I'm sure people know, you like to put the variable loads as close
to the balance point of the A/C as possible to that as fuel varies,
passengers get in out out, or the pilots weight goes up and down, the
plane remains stable and flyable.

So in the back to back seating config, everybodies butt is pretty
close to that point.

Regards

"Rick Pellicciotti" wrote in message news:3f0c8596$1@ham...
This can't be right. If you stop and think about it, the most the CG could
move would be the distance that the center of mass of the passenger changed.
Maybe a foot at most.

rick

"Jay" wrote in message
om...
Depending on the amount of leg room you allow and how much the seat is
reclined, I got about 3 feet difference in passenger CG. And I'm not
counting the kind of seating where the guy in back's legs go around
the guy in front's seat (Soneri?).

At take off and landing the backwards seat could be a little wierd,
but at cruise altitude, you can hardly tell the difference. Flown
backwards several times on commercial jets and didn't even notice once
we were airborne.

(Bob Kuykendall) wrote in message
. com...
Earlier,
(Jay) wrote:

Noticed White Lightning used the same back to
back seating I've been playing with for my
concept design...
Seemed like the only reasonable way to handle
the CG for a wing with a relatively high aspect.

Actually, John Roncz explored back-to-back seating for a design that
he was doing. But he abandoned that plan after discovering that it
made only a very small difference in the CG of the seated occupant. I
think that he weighed that small advantage against the discomfort that
many potential passengers expressed with traveling backwards.

I think that this episode is described in a series of articles that he
published in Sport Aviation in 1990. According to this, I think it was
in either the May 1990 or the February 1991 article:

http://www.cozybuilders.org/ref_info/sportavi90.html

Thanks, and best regards to all

Bob K.

 




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