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TECHNICAL PAPERS
S solved by ELASTIC STOP’
either of two ways. The body may be raised to ^chanisms by
reduce the lift or an underpan may be added
dy in proxim
For bolting two non-parallel sur to prevent the thick boundary layer.
faces, this two-piece, self-align The methods thus far discussed for reduc-
ing and self-locking fastener cuts
to
costs by eliminating spot facing ing the drag and the lift of a body have been
or milling operations. concerned primarily with providing a less
4
restricted path for the flow of air between the
undersurface and the ground. Similar results 3
may be obtained by severely restricting the
For spring-mounted connections flow of air beneath the vehicle.
r
or dynamic balancing, this spec
-
ial nut stays put, yet is easily ad The force on the cylinder that is uniformly
justed. (Flanged face eliminates in contact with the surface varies only as the
need for extra washers.) pressures on its upper surface, but the net
force on the other two cylinders also is af
r fected by the pressures acting between them .
and the ground plane. With the spoiler or re
K Locked anywhere on the bolt: striction located at the rear, the pressure exist- ’
i ing at the forward edge of the cylinder is free
to act beneath the entire cylinder and since
this pressure is high, the positive lift of the
On make-and-break adjustment
studs, this “thin-height” nut de body is increased no matter where the separ ' flow betwee
sign maintains accurate contact ation point is located. If the spoiler is located
oo
gaps. It’s perfect where limited at the front of the cylinder, the pressure exist e in which n<
clearance is a problem or for t in which tl
shear applications. ing at the rear is felt beneath the body. This ist be consid
pressure changes with the location of the flow
;ed upon the
separation point. When there is no flow sepa-
inder. As me
I Tj >ught into cc
to For bolted connections requiring § ) lance of the
predetermined play or precision
positioning, Elastic Stop nuts do ( i s body increa
not “travel” under vibration; yet ■atly increase
nt can prod
are readily re-positioned. L 1 3 >ince raising
L ift co e fficie n t — 2 :ause of the
ter course
•l ll 1 uld be tow
For rubber-insulated and cushion
10 mountings where the nut cannot itilated und<
be wrenched against a firm seat 0 erating on r
ing surface, the Elastic Stop nut
guarantees a secure connection.
ZTT 150 135 120 90*—
Separation angle in degrees — O
EFFECT OF SPOILER LOCATION ON Hoerner, S. F.;
LIFT OF SEMICIRCULAR CYLINDER uthor; 1958.
MOVING VERY CLOSE TO SURFACE
'. Cornish, J. J.; “A
tening problems, eliminating extra parts and operations .. . Roadster”; Aerophys\
niv.; October 1965
.ASTIC STOP® nut grips bolt threads with a perfect fit that will ration, as in the case of potential flow, the pres Cornish, J. J., an<
stress reversals, and seals against liquid seepage. By bringing sure at the rear is the same stagnation pressure istics of Forty-
that is felt at the front of the cylinder. When, No. 23, Missist
firm contact, it eliminates wear-producing axial play. The smooth
as in any real case, flow separation occurs on 'hite, Joseph F.;
rdoes not distort or gall bolt threads. It is reusable many times,
the body, the pressure at the rear is lower than r presented at
ning Problems on Industrial Equipment “Vibration-Proofed” with nt; 1960.
at the front. It can be seen that this lower pres
hlichting, H.;
sure beneath the cylinder reduces the net lift l.R.D. Report ;
FASTENER DIVISION as the separation point moves forward. In the
UT CORPORATION OF AMERICA case of the semicircular cylinder, the net ef
fect is actually a negative lift for the more up
2330 Vauxhall Road, Union, New Jersey acted from a pc
stream separation points.
he red nylon ring of reliability neering Congr
It can be seen that there are two separate
r 948B.
Circle Service No. 125
