 |
|||
|
|
|||
| ||||||||||
|
|  MIL-J-7093A
(Weps)
parts. Each group of four (4) motors shall be conditioned and test fired (in
accordance with 4.8.3) alternately at -75F and at 150F.
4 . 5 . 2 . 3 . 2 Acceptance. - Acceptance of the sixteen (16) lots from which the
sample of four (4) was withdrawn shall be based on the ballistic performance of
the test motors selected therefrom.
Control Charts. - The contractor shall maintain statistical control
4.5.2.4
charts for each of the five (5) basic ballistic parameters (paragraph 3.3.1) for
alI motors submitted for acceptance under the Normal Sampling Schedule at each
of the temperatures -75F and 150F.
Range Charts. - A "statistical control index rating", QR, for each
4.5.2.5
of the range charts shall be computed according to the formula:
Where
a is the percent of values on the range chart outside of the 3 σ limit,
(paragraph 4.6).
Data and Calculations. - Prior to initiation of the Normal Sampling
4.5.2.6
Schedule, the contractor shall submit data and necessary calculations to demonstrate
that the statistical control index rating for each of the range charts is at least 85%
for 200 consecutive firings.
Range Chart Index Rating. - As part of the requirements for continued
4.5.2.7
application of the Normal Sampling Schedule, the statistical control index rating
for the range charts (4.5.2.5) shall be computed continuously. The computation
shall include data from 50 sub-groups accumulated prior to the time of calculating
statistical control index ratings. Continuance of the Normal Sampling Schedule
requires, in part, that the statistical control index rating for the range charts shall
be at least 85%. If the computed value is less than 85%, the Normal Sampling
Schedule shall be discontinued immediately, and the Intermediate Production
Schedule shall be applied. A value of less than 85% for the index rating shall not be
cause for rejection of units accepted under the Normal Sampling Schedule (para-
graph 4.5.2.3). In order to resume the Normal Sampling Schedule, the con-
tractor shall submit data and necessary calculations to demonstrate that the sta-
tistical control index rating for each of the range charts is at least 85% for 200
consecutive firings, or that the factor responsible for the low QR rating has been
found and corrected.
Mean Value. - A "statistical control index rating", Qx, for each
4.5.2.8
of the mean value charts (4.5.2.4) shall be computed according to the formula:
Where:
limits (para-
b is the percent of values outside of the
7
graph 4.6).
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals