h*l
发帖数: 807 | 1 read between the lines,you can figure out what it means.
Assertion: F-22 production uses a shim line and national spreading of
suppliers has cut quality, thus the F-22 lacks interchangeable parts.
Fact: The F-22 does not have a shim line. During the earliest stages of
production while tooling was undergoing development, there were a few
aircraft with slight differences which were subsequently modified. The F-22
supplier base is the best in the industry, as demonstrated by the aircraft’
s high quality and operational performance. All operational F-22s today have
interchangeable parts
==========
F-22 Assertions and Facts
July 2009
Assertion: F-22 maintenance man-hours per flying hour have increased,
recently requiring more than 30 hours of maintenance for every hour airborne.
Facts: The F-22 is required to achieve 12.0 direct maintenance man-hours per
flight hour (DMMH/FH) at system maturity, which is defined to be when the F
-22 fleet has accumulated 100,000 flight hours. In 2008 the F-22 achieved 18
.1 DMMH/FH which then improved to 10.5 DMMH/FH in 2009. It’s important to
recognize this metric is to be met at system maturity, which is projected to
occur in late 2010. So the F-22 is better than the requirement well before
maturity.
Assertion: The airplane is proving very expensive to operate with a cost per
flying hour far higher than for the warplane it replaces, the F-15.
Facts: USAF data shows that in 2008 the F-22 costs $44K per flying hour and
the F-15 costs $30K per flying hour. But it is important to recognize the F-
22 flight hour costs include base standup and other one-time costs
associated with deploying a new weapon system. The F-15 is mature and does
not have these same non-recurring costs. A more valid comparison is variable
cost per flying hour, which for the F-22 in 2008 was $19K while for the F-
15 was $17K.
Assertion: The aircraft's radar-absorbing metallic skin is the principal
cause of its maintenance troubles, with unexpected shortcomings.
Fact: Stealth is a breakthrough system capability and it requires regular
maintenance, just like electronics or hydraulics. The skin of the F-22 is a
part of the stealth capability and it requires routine maintenance. About
one-third of the F-22’s current maintenance activity is associated with the
stealth system, including the skin. It is important to recognize the F-22
currently meets or exceeds its maintenance requirements, and the operational
capability of the F-22 is outstanding, in part due to its stealth system.
Assertion: The F-22 is vulnerable to rain and other elements due to its
stealthy skin.
Facts: The F-22 is an all-weather fighter and rain is not an issue. The F-22
is currently based and operating in the harshest climates in the world
ranging from the desert in Nevada and California, to extreme cold in Alaska,
and rain/humidity in Florida, Okinawa and Guam. In all of these
environments the F-22 has performed extremely well.
Assertion: We're not seeing the mission capable rates expected and key
maintenance trends for the F-22 have been negative in recent years.
Facts: The mission capable (MC) rate has improved from 62% in 2004 to 68%
percent in 2009. And it continues to improve, the current MC Rate in the F-
22 fleet is 70% fleet wide.
Assertion: The F-22 can only fly an average of 1.7 hours before it gets a
critical failure that jeopardizes success of the aircraft's mission.
Facts: Reliability is measured by Mean Time Between Maintenance (MTBM). One
of the F-22 Key Performance Parameters (KPPs) is to have an MTBM of 3.0
hours at system maturity, which is defined to be when the F-22 fleet has
accumulated 100,000 flight hours. Through 2008, F-22s averaged 2.0 hours
MTBM while the fleet has accumulated 50,000 flight hours. The F-22 is on-
track to meet or exceed 3.0 hours of MTBM at system maturity, projected to
occur in late 2010, and the latest delivered F-22s, known as Lot 6 jets, are
exhibiting an MTBM of 3.2 hours.
Assertion: The plane's million-dollar radar-absorbing canopy delaminates and
loses its strength and finish.
Facts: The F-22 canopy balances multiple requirements: mechanical strength,
environmental resistance, optical clarity and other requirements. Initial
designs for the canopy did not achieve the full life expectancy of 800 hours
. The canopy has been redesigned and currently two companies are producing
qualified canopy transparencies that meet full service life durability of
800 hours.
Assertion: The F-22 has significant structural design problems that forced
expensive retrofits to the airframe.
Facts: The F-22 had a series of structural models that were tested
throughout its development in a building block manner. Lockheed Martin
completed static and fatigue testing in 2005 on two early production
representative airframes. The results of those tests required upgrades to
the airframe in a few highly stressed locations. Follow up component level
testing was completed and structural redesigns were verified and implemented
into the production line. For aircraft that were delivered prior to design
change implementation, structural retrofit repairs are being implemented by
a funded program called the F-22 Structural Retrofit Program. Structural
reinforcements are common during the life of all fighters and have occurred,
or are occurring, on the F-15, F-16 and F/A-18.
Assertion: The F-22 has a significant design flaw in the fuel flow system
that forced expensive retrofits to the airframe.
Facts: The F-22 fuel system has not required redesign. Similar to other
aircraft, the systems on the F-22 are continually being enhanced by a
reliability and maintainability improvement program. For example, early fuel
pumps turned out to not be as reliable as desired and have subsequently
been replaced by more reliable pumps.
Assertion: Follow-on operational tests in 2007 raised operational
suitability issues and noted that the airplane still does not meet most of
its KPPs.
Facts: The F-22 has 11 Key Performance Parameters (KPPs). The F-22 exceeds 5
KPPs (Radar Cross Section, Supercruise, Acceleration, Flight Radius, and
Radar Detection Range). The F-22 meets 4 KPPs (Maneuverability, Payload,
Sortie Generation and Interoperability). The remaining 2 KPPs are
sustainment metrics (MTBM and C-17 Loads) that are to be evaluated at weapon
system maturity -- which is defined as 100,000 total flight hours and is
projected to occur in late 2010. These two sustainment metrics are on-track
to be met at 100,000 flight hours.
Assertion: The F-22 costs $350M per aircraft.
Facts: The F-22s currently being delivered have a flyaway cost of $142.6M
each, which is the cost to build and deliver each aircraft. This number does
not include the costs for research and development (that were incurred
since 1991), military construction to house the aircraft, or operations and
maintenance costs.
Assertion: The F-22 needs $8 billion of improvements in order to operate
properly.
Facts: Similar to every other fighter in the U.S. inventory, there is a plan
to regularly incorporate upgrades into the F-22. F-22s in their current
configuration are able to dominate today’s battlefield and future upgrades
are planned to ensure the F-22 remains the world's most dominant fighter. F-
22 Increment 3.1, which will begin entering the field in late 2010, adds
synthetic aperture radar (SAR) mode in the APG-77 radar, and a capability to
employ small diameter bomb (SDB). Increment 3.1 is in flight test today at
Edwards AFB, CA. Increment 3.2 is being planned and will add AIM-120D and
AIM-9X weapons along with additional capabilities.
Assertion: F-22 production uses a shim line and national spreading of
suppliers has cut quality, thus the F-22 lacks interchangeable parts.
Fact: The F-22 does not have a shim line. During the earliest stages of
production while tooling was undergoing development, there were a few
aircraft with slight differences which were subsequently modified. The F-22
supplier base is the best in the industry, as demonstrated by the aircraft’
s high quality and operational performance. All operational F-22s today have
interchangeable parts.
Assertion: The F-22 has never been flown over Iraq or Afghanistan.
Facts: The F-22 was declared operational in 2005, after air dominance was
achieved in South West Asian Theater of conflict. Due to the absence of air-
to-air or surface-to-air threats in these two theaters, stealthy air
dominance assets were not an imperative. 4th generation fighters operate
safely and effectively supporting the ground war in Iraq and Afghanistan.
The best weapon may be the one that isn’t used but instead deters a
conflict before it begins. Just as we have Trident submarines with nuclear
weapons, and intercontinental ballistic missiles that were not used in the
current conflicts, we need air superiority capabilities that provide
deterrence. The F-22 provides those capabilities for today’s contingencies
as well as for future conflict. It is important to remember that the F-15
was operational for 15 years before it was first used in combat by the USAF. | t*n
发帖数: 14458 | 2 太长
abstract please
22
have
【在 h*l 的大作中提到】
: read between the lines,you can figure out what it means.
: Assertion: F-22 production uses a shim line and national spreading of
: suppliers has cut quality, thus the F-22 lacks interchangeable parts.
: Fact: The F-22 does not have a shim line. During the earliest stages of
: production while tooling was undergoing development, there were a few
: aircraft with slight differences which were subsequently modified. The F-22
: supplier base is the best in the industry, as demonstrated by the aircraft’
: s high quality and operational performance. All operational F-22s today have
: interchangeable parts
: ==========
| m****1
发帖数: 352 | | n*****r
发帖数: 1981 | 4 基本上就是F22有各种问题，但是未来前景这些问题都会缓解，或是换个角度看这些都
不是大问题。。。 | m****1
发帖数: 352 | | d*****t
发帖数: 7903 | 6 最后一段和 Trident submarines with nuclear weapons, and intercontinental
ballistic missiles 相比较是挺搞笑的。
语言就是一门艺术。 | a*****s
发帖数: 6260 | 7 没啥大问题啊。照网上谣传的那些标准，F-15当年也是完全的垃圾，像C-5这种
就更加了。
22
have
【在 h*l 的大作中提到】
: read between the lines,you can figure out what it means.
: Assertion: F-22 production uses a shim line and national spreading of
: suppliers has cut quality, thus the F-22 lacks interchangeable parts.
: Fact: The F-22 does not have a shim line. During the earliest stages of
: production while tooling was undergoing development, there were a few
: aircraft with slight differences which were subsequently modified. The F-22
: supplier base is the best in the industry, as demonstrated by the aircraft’
: s high quality and operational performance. All operational F-22s today have
: interchangeable parts
: ==========
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