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medicdwpa wrote:I know why the F-15 had them removed, just wonder why they did not do the same on the F-16??
Obi_Offiah wrote:medicdwpa wrote:I know why the F-15 had them removed, just wonder why they did not do the same on the F-16??
My understanding it that they were not as reliable on the Eagle and prone to detaching due to aerodynamic influences in that region. The F-16 doesn't suffer from the same aero characteristics here.
Roscoe wrote:Speaking of turkey feathers and Vipers, back in 1997 or so we re looking at an initiative to modify the engines (I forget which manufacturer, GE or PW). The mod would add additional bypass cold airflow on the outside of the nozzle (reducing temperatures and therefore increasing turkey feather life) and also modifying how the turkey feathers were attached, simplifying R&R. The net result was expected to be approx a 60x reduction in repair costs per nozzle over the life of the engine. It was going to more than pay for itself...except we didn't have the funds for the initial investment so it was never implemented to my knowledge.
Wonder if anyone knows if this was ever picked back up...?
The 'simpler' attachment is evident in the PW-229 Nozzle; the slip on bearing-posts & single aft-hinge bolt. That was already in the cards.
The 'cooled-nozzle' was part of the LOAN (Low Observable Axisymmetric Nozzle) program; they were going to use the 'advanced cooling' part to make the nozzle last longer (even if without the advanced shape or other new parts) You can see the 4 large round air inlet holes between each actuator in the nozzle support in the image below.
As for extending the life of the augmentor, that's been accomplished through the PW-229 program as well. When I began working F100s the nozzle TBO was 1200Hrs; then extended to 2000 cycles; the '97 Package' PW-229s came equipped with a 4300 cycle nozzle; now all the remaining PW-220 nozzles are being modified in the field at overhaul to a 4300 cycle configuration.
Don't know why they used axisymmetric in the name; pretty much any nozzle (including 2/3D nozzles) "have symmetry around an axis"
Guess they needed an A to form the word LOAN?
Back to the point - the nozzles now last over 50% longer than they did in the early to mid 1990s, and the PW-229 Turkey Feathers are MUCH easier to remove/reinstall. So even though the LOAN didn't give the nozzle better LO attributes and the initial $$ weren't spent to save logistics costs, at least the latter has been funded through normal "support" funding. (Search for CIP continuous improvement program and your choice of engine type.)
See also: http://www.f-16.net/f-16_versions_article20.html
Keep 'em flyin'
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