Wednesday, March 17, 2010

Your JSF Update


Just the landing


The short take off & vertical landing & cheesy music.


F136 at full reheat using JSF nozzle
The aircraft appears to have performed well in this maneuver, though it was conducted at a lighter weight than would be used in combat.

They will be taking the weight up to around 5,000 lbs of fuel and weapons as they expand the envelope.

From the video, there is no evidence of problems with things like spalling the tarmac, but this is at Pax River, and the airfield there is rather robust.

Of course, this technical success does not make the program any better run, as shown by the latest Pentagon price estimates which show the cost of the plane increasing by 90%, to $135 million each, up from the original $69 million ( inflation adjusted, it was $50m in 2001 dollars) promised in 2001.

Additionally, because of cost and weight issues, the F-35 will be eliminating fire extinguishers and "shutoff fuses for engine fueldraulics lines," which will increase vulnerability to ground fire, and make the aircraft more vulnerable to things like light AAA and small arms fire, which makes it less attractive to operate in a close air support.

All in all, this reminds me of the death throws of the Naval F-111B, where they were literally pulling glass off the gauges and replacing it with plastic, in an attempt to get the weight low enough to make a carrier landing feasible.

Finally, the GE/Rolls-Royce F136 alternate engine has hit full thrust in reheat (paid subscription required) on the test stand, and results indicate a thrust margin above that of P&W's F135:
With all the improvements in place, DiLibero says Engine 006 test results so far indicate performance and durability is exceeding design expectations and turbine inlet temperatures are cooler than planned. “So that’s more margin for durability, or power,” he adds. GE/Rolls-Royce declines to comment on the top thrust levels achieved in maximum afterburner, but the team previously said it anticipated an estimated 5% margin over the F-35’s baseline Pratt & Whitney F135 powerplant.

“Both engine developers are working to the same specifications, and our customer has made it clear it is not in anybody’s interests to be over. However, we’re on firm ground by saying we have margin,” says F136 marketing manager Tim Morison. GE/Rolls-Royce says the additional thrust may be particularly valuable for increasing weapons bring-back capability and hover performance for the F-35B Stovl version. “We think the three-stage low-pressure turbine is what drives the margin in Stovl,” Morison says.
Considering the cost increases that appear to be in the pipe for the F135, as well as the ongoing issues with bringback weight with the STOVL version, it does seem to me that continued development of the F136 is prudent.

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