Elegant engineering

In the latest Air & Space magazine is a surprisingly technical article on
the spar problems on the T-34 Mentors. It shows how Mentor wings (and I
presume Bonanza and many other Beech wings) are assembled. Instead of being
riveted completely together they are in three main pieces. (1) A main spar
with many of the ribs attached, (2) a leading edge that apparently slips
over the fronts of these ribs, and (3) the trailing edge that includes the
secondary spar, flaps, ailerons, etc. These are all held together with four
"piano hinges" two at the top and two at the bottom. To separate the pieces
you simply pull the "hinge pins" (stainless steel wires running the length
of the wings) out and the leading and trailing edge pieces pull away from
the spar, exposing most of the inside of the wings. This makes it easy to
get inside the wing for complete inspection of the spar and everything else.
I'd never appreciated this design feature, but it makes a lot of sense.
Just some elegant engineering that most of us engineers and would-be
engineers can appreciate.

--
Bob (Chief Pilot, White Knuckle Airways)

I don't have to like Bush and Cheney (Or Kerry, for that matter) to love
America

Elegant from the assembly point of view but it left a surface
discontinuity/air leak at a critical point on the airfoil that was
guaranteed to trip the flow to turbulent. It also provided a path for water
to get inside the wing possibly causing corrosion. The steel piano wire in
contact with the aluminum didn't help with that either.

That said, it's a potentially good idea that could use some updating.

Bill Daniels

"Bob Chilcoat" wrote in message
...
In the latest Air & Space magazine is a surprisingly technical article on
the spar problems on the T-34 Mentors. It shows how Mentor wings (and I
presume Bonanza and many other Beech wings) are assembled. Instead of
being
riveted completely together they are in three main pieces. (1) A main
spar
with many of the ribs attached, (2) a leading edge that apparently slips
over the fronts of these ribs, and (3) the trailing edge that includes the
secondary spar, flaps, ailerons, etc. These are all held together with
four
"piano hinges" two at the top and two at the bottom. To separate the
pieces
you simply pull the "hinge pins" (stainless steel wires running the length
of the wings) out and the leading and trailing edge pieces pull away from
the spar, exposing most of the inside of the wings. This makes it easy to
get inside the wing for complete inspection of the spar and everything
else.
I'd never appreciated this design feature, but it makes a lot of sense.
Just some elegant engineering that most of us engineers and would-be
engineers can appreciate.

--
Bob (Chief Pilot, White Knuckle Airways)

I don't have to like Bush and Cheney (Or Kerry, for that matter) to love
America

Bob Chilcoat wrote:
To separate the pieces
you simply pull the "hinge pins" (stainless steel wires running the length
of the wings) out and the leading and trailing edge pieces pull away from
the spar, exposing most of the inside of the wings. This makes it easy to
get inside the wing for complete inspection of the spar and everything else.

Easy in theory. In practice, removing the "hinge pin" thats been in place
for 50+ years is near impossible. The only thing more difficult is
threading one back in. Must confess, I've never done it personally, but
the stories to be told...

On the otherhand, when Beech built the first Bonanzas, I'm sure they
didn't expect that they would still be flying 50 years later.


--
Frank Stutzman
Bonanza N494B "Hula Girl" (1949 A35)
Hood River, OR

Bob Chilcoat wrote:
This makes it easy to
get inside the wing for complete inspection of the spar and everything else.
I'd never appreciated this design feature, but it makes a lot of sense.

Bob (Chief Pilot, White Knuckle Airways)



If you ever get the chance to look inside the detachable wing of a Dyke
Delta, you'll see true 'inspectability' (look Ma', I just made up a word).

The rib caps are a 1/2"x1/4" stainless steel channel that is braced with
3/8" piper channel. You can just about stand inside the thing and look
around. Well, maybe I could if I would lose this gut, but I'm talking
about normal people, not me. 8*)

--
http://www.ernest.isa-geek.org/
"This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

On Thu, 2 Dec 2004 09:57:48 -0500, "Bob Chilcoat"
wrote:

To separate the pieces
you simply pull the "hinge pins" (stainless steel wires running the length
of the wings) out and the leading and trailing edge pieces pull away from
the spar, exposing most of the inside of the wings. This makes it easy to
get inside the wing for complete inspection of the spar and everything else.
I'd never appreciated this design feature, but it makes a lot of sense.
Just some elegant engineering that most of us engineers and would-be
engineers can appreciate.

I have a friend who owns a Bonanza and he just had the leading edge
replaced on his left wing. The job went relatively easy although the
standard procedure apparently was to use an air hammer against the
steel rod as it's being re-installed to attach the leading edge.

Corky Scott

Corky,

Are you making loud noise in the woods yet?

I figure that you should be blowing leaves by now.

BTW, I know someone with nine lives, who is developing his auto
conversion in the sky. Made me think of you, and hoping that you
see many hours of ground test. (I did almost 40 hrs before flight)


George Graham
RX-7 Powered Graham-EZ, N4449E
Homepage http://bfn.org/~ca266

On Sun, 5 Dec 2004 10:31:13 -0500, "George A. Graham"
wrote:

Corky,

Are you making loud noise in the woods yet?

I figure that you should be blowing leaves by now.

BTW, I know someone with nine lives, who is developing his auto
conversion in the sky. Made me think of you, and hoping that you
see many hours of ground test. (I did almost 40 hrs before flight)


George Graham

Work has temporarily halted, although a full slate of engine
development on the ground is the plan.

My wife decided that after watching me spend lots of money on a toy
for 15 years, it was time we put something back into the house, like a
totally renovated kitchen.

I didn't have to think twice, I pitched in immediately, no question.
How could I not? She's been extremely supportive regarding the
"project", even though it's useless except for me to bore holes in the
sky with it once it's finished. She is not thrilled about flying
although she dutifully goes with me once a year or so for a tour of
the upper valley. It's pathetically obvious she's uncomfortable. The
pressure changes hurt her ears.

So I've been carpenter, electrician and plumber for the last several
months, instead of airplane builder.

The old wall hung cabinets have been removed, the stain sanded off and
have been revarnished. They'll get new glass doors, which I will not
be doing. The new floor cabinets have arrived just this past Saturday
and I spent both days of the weekend varnishing their exterior. There
are 8 of the things and each one takes at least an hour to varnish,
not to mention the extra panels that will be decorating the backside
of the pennisula, which also require varnishing.

I'll also have to install the new dishwasher and stove, when they get
here.

So there has been no time for play. My wife was worried that I'd be
upset that I could not work on the airplane. I appreciate her
concern, but the priority is crystal clear: House/marriage always
trumps expensive play thing.

I probably will not be able to return to steady work on the Christavia
until sometime in March. Too bad because I'm very very close to
firing up the engine for the first time. It's sitting in it's test
stand with the instrument panel with all the instruments I need pretty
much wired up except an EGT guage. I probably will not be able to buy
that as they are pretty expensive.

I was going to send out the headers to be Jet Hot coated but they
recommend that I run the engine for a bit before sending them to their
coating plant. That suits me, I don't want to delay running the
engine once I'm back at it again.

Corky (I'm bushed) Scott

I didn't have to think twice, I pitched in immediately, no question.
How could I not? She's been extremely supportive

but the priority is crystal clear: House/marriage always trumps expensive play thing.

Corky (I'm bushed) Scott



Very, very smart man............

On Mon, 06 Dec 2004 16:11:17 GMT, "Don Lewis n FTW"
wrote:



I didn't have to think twice, I pitched in immediately, no question.
How could I not? She's been extremely supportive

Besides the expensive play toy is usually cheap compared to property
settlement.

Joyce says that is we ever split she want's her half of the airplane
and she means that literally. (with a chain saw) :-)) But after
this many years I think it's probably going to last.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

but the priority is crystal clear: House/marriage always trumps expensive play thing.

Corky (I'm bushed) Scott



Very, very smart man............

On Mon, 6 Dec 2004, Corky Scott wrote:

It's pathetically obvious she's uncomfortable. The
pressure changes hurt her ears.

Good man Corky.
BTW, When she gets to fly often enough, she will likely learn to
manipulate the pressure in her ears.

You hold your nose and attempt to breath in climb, blow your nose
when coming down.

Visiting grandbabies is the best reason to fly long distance,
any moves in that direction yet with your girls?

George Graham
RX-7 Powered Graham-EZ, N4449E
Homepage http://bfn.org/~ca266