| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 137.2 | Webs or Shear Webs | ROYCE::HORNBY | | Wed Apr 22 1987 09:27 | 14 |
| Kay,
I agree with Dan for "shear webs" but my understanding of Web
is a triangular piece of balsa that strengthens the junction between
the trailing edge and the rib,(or could be leading edge with the
choice of a single one or one each side. These are commonly used to
stengthen the the joint at the dihedral break.
| |\ | |
trailing | \ rib | |Leading
edge | |==========================| | edge
| | / | |
| |/ Web (usally 45 degrees)
Trev.
|
| 137.4 | Shear Gussets... | TALLIS::FISHER | Kay R. Fisher | Wed Apr 22 1987 09:54 | 11 |
| In this particular plan they were rectangular pieces of balsa and the
top view didn't show them - so they fit Dan's first definition.
Thanks for the quick answers. Both were very informative.
_!_
Bye ----O----
Kay R. Fisher / \
==============================================================
|
| 137.5 | I could be wrong, but... | CRVAX1::KAPLOW | There is no 'N' in TURNKEY | Wed Apr 22 1987 19:13 | 6 |
| ...where I come from, the reinforcing in .1 is a shear web, and
that described in .2 is a gusset.
Grain direction IS important in each case. The shear web grain
should be vertical, the gusset grain is at a 45 degree angle to
the rib and {leading edge, trailing edge, spar}.
|
| 137.6 | shear webbing must be perpendicular | LEDS::COHEN | | Wed Aug 03 1988 12:01 | 19 |
|
Wings built with a top and bottom spar can "twist". When torque
is applied to the wing, the upper spar is forced to move in a
direction opposite that of the lower spar (this motion is always
along the long dimension of the spar). Shear Webs are added
between the spars to control this "sliding" as a result of twist.
It is a very common means to provide extra strength in a light
wing structure, and is used extensively in glider wings. When
combined with upper and lower leading edge sheeting, it is often
refered to as "D-Box" construction. The key here is that, in
order for the webs to provide any real added benefit, the grain
MUST run perpendicular to the spars, or, when the spars attempt to
move, the webs will split along the direction of their grain.
Unless there is some other reason for the webs in your wing, you
are correct in your assumption. They seem to have been applied
incorrectly.
|
| 137.7 | shear webbing gives vertical strength | PNO::CASEYA | THE DESERT RAT (I-RC-AV8) | Wed Aug 03 1988 12:42 | 23 |
| Jeff,
.-1 is absolutely correct except that we are not dealing with "twist,"
at least not in the way I understand the term, as much as we're
dealing with "shear" (hence the name) when we install shear-webbing.
When extreme load, positive or negative, is placed on a wing, one
spar is compressed while the opposite one is placed in extension.
Failure to provide for stopping this will allow the wing to break
(shear) at its weakest point, a.k.a. "shedding a wing."
For shear-webbing to be of any particular value, you and Randy are
correct in that it _must_ be installed with the grain running vertical
(perpendicular) with respect to the spars. As you speculate, the
horizontal-grained webbing is more a placebo in that, in an extreme
situation, it could fail as it has no resistance to being compressed
which is the effect on the webbing in a heavy-load situation.
|
| | 00 Adios, Al
|_|_| ( >o
| Z__(O_\_ (The Desert Rat)
|