An allowance
on the maximum tire dimensions shown in the tables must be made to
compensate for the growth or stretch of the tire fabric during service.
It is important that the following rules be observed by anyone using
aircraft tire dimensions.
Note:
Radii Ws/2 and Wsg/2 are drawn through their respective shoulder
points tangent to Do and Dg respectively.
Radii
below the shoulder points pass through the shoulder points and are
tangent to W and Wg respectively.
| D |
= |
Rim Ledge Diameter |
| *Do |
= |
Maximum Outside Diameter |
| *H |
= |
Maximum Section Height |
| *W |
= |
Maximum Cross Section Height |
| *Ds |
= |
Maximum Shoulder Diameter |
| *Hs |
= |
Maximum Shoulder Height |
| *Ws |
= |
Maximum Shoulder Width |
| Wg |
= |
Maximum Grown Section Width |
| Dg |
= |
Maximum Grown Outside Diameter |
| Wsg |
= |
Maximum Grown Shoulder
Width |
| Dsg |
= |
Maximum Grown Shoulder
Diameter |
* Dimensions
of new, unused inflated tire.
Obtain
new tire dimensions Do, Ds, W and Ws shown in the tire tables as
maximum. Note: Dimensions "W" and "Wg" include
all protective side ribs, lettering, bars and decorations. Determine
"grown" dimensions as follows: (use appropriate growth
factor form graph)
| Wg |
= |
Gw (W) |
| Dg |
= |
D + 2 (Gh) (H) |
| Wsg |
= |
Gw (Ws) |
| Dsg |
= |
D + 2 (Gh) (Hs) |
| H |
= |
(Do - D) /2 |
| Hs |
= |
(Ds - D) /2 |
SECTION
HEIGHT
GROWTH
FACTOR
(Gh) |
 |
|
ASPECT RATIO (AR) |
Section
Growth Factor Gw = 1.04
Section Height Growth Factor Gh = 1.151 - (.075 x AR)
Clearance
allowances between the tire and the adjacent parts of the aircraft
must be made by the aircraft manufacturer. These allowances are
to be based on the maximum overall tire dimensions shown in the
tables, plus growth allowance due to service, plus the increase
in diameter due to centrifugal force. Minimum distances to adjacent
parts of the aircraft are determined as follows:
1. Determine
maximum grown tire envelope as instructed in chart on previous page.
(This is the dotted line labeled "used inflated tire.")
2. Obtain
radial clearance Cr and lateral clearance Cw from the following
formulae:
| Cr |
= |
.073 Wg + 0.4 for 250 MPH |
|
Cw = .019 Wg + .23 |
|
|
.060 Wg + 0.4 for 225 MPH |
|
|
|
|
.047 Wg + 0.4 for 210 MPH |
|
|
|
|
.037 Wg + 0.4 for 190 MPH |
|
|
|
|
.029 Wg + 0.4 for 160 MPH |
|
|
The following
is a graphic representation of the above formulae:
3. Determine
distance to adjacent parts as follows:
| Rx (Min.) |
= |
Radial distance from axle
C/L to adjacent part. |
|
= |
(Dg /2) + Cr |
|
|
|
| Wx (Min.) |
= |
Lateral distance from the
C/L to adjacent part. |
|
= |
(Wg /2) + Cw |
|
|
|
| Sx Radius (Min.) |
= |
Clearance allowed between
tire shoulder area and adjacent part |
|
= |
Cw + Cr
-----------
2 |
 Courtesy
of The Goodyear Tire & Rubber Company
|
