What will be the USNs primary F-35 naval strike weapon?

madrat · by **madrat** » 26 Feb 2019, 14:08

Energy efficiency is one aspect. Energy density of the fuel is another.

steve2267 · by **steve2267** » 26 Feb 2019, 14:25

madrat wrote:Energy efficiency is one aspect. Energy density of the fuel is another.

Pretty sure the JASSM already was burning kerosene (JP-8?) before. Not sure how LM increases the "energy density" of the fuel, then. Pretty sure they can't pull any Elon Musks and densify the fuel by deep chilling. Perhaps alien tech from Area 51? Otherwise... care to elaborate?

marauder2048 · by **marauder2048** » 26 Feb 2019, 18:43

JASSM already runs on JP-10 which has greater volumetric energy density than JP-8.
There's been research on further improving JP-10 combustion efficiency with nanoparticle additives.

As popcorn mentioned, they have talked about reducing the warhead to accommodate more fuel.
IIRC, the front fuel tank is wrapped around the warhead.

steve2267 · by **steve2267** » 26 Feb 2019, 19:13

Well, live and learn. I've been schooled on JP-10, a synthetic fuel with 14% greater energy density per unit volume than JP-8. I assumed (my bad) the military would have been using JP-8 (or JP-5) to ease logistics.

marauder2048 · by **marauder2048** » 26 Feb 2019, 19:29

steve2267 wrote:Well, live and learn. I've been schooled on JP-10, a synthetic fuel with 14% greater energy density per unit volume than JP-8. I assumed (my bad) the military would have been using JP-8 (or JP-5) to ease logistics.

No logistics burden (for the first couple of decades: i've seen 28 years for the shelf life of JP-10)
since AUR cruise missiles are typically fueled by the manufacturer before delivery.

wolfpak · by **wolfpak** » 26 Feb 2019, 20:22

What happened to the JASSM XR proposal with the lengthened fuselage and canards?

steve2267 · by **steve2267** » 26 Feb 2019, 21:33

wolfpak wrote:What happened to the JASSM XR proposal with the lengthened fuselage and canards?

Dunno about the canards... but LM was awarded some $58M last Sept (9/2018) to develop the XR:

Lockheed Martin Developing "Extreme-Range" JASSM Variant
by John A. Tirpak 9/13/2018

Lockheed Martin will upgrade its stealthy JASSM conventional cruise missile, under a $51.08 million contract awarded by the Air Force's Life Cycle Management Center at Eglin AFB, Fla. The upgraded missile will be known as the JASSM-XR, for "Extreme Range," a development of the JASSM-ER, or "Extended Range."

A Lockheed Missiles and Fire Control spokesman said the new version is "part of a planned upgrade" of the JASSM "family of missiles" which includes the baseline AGM-158A JASSM, the AGM-158B JASSM-ER, and the Long-Range Anti-Ship Missile AGM-158C. The Air Force could not immediately say if the most recent variant will carry the designation AGM-158D.

The upgrade includes a new missile control unit computer, "which will support the other planned capabilities," the spokesman said. These include "new wing designs to increase standoff range through aerodynamic efficiency, and a new GPS unit to further advance our level of protection." The Air Force will acknowledge only that the JASSM-ER has a range in excess of 500 nautical miles, so the XR's range will presumably be greater.

The contract noted the other work to be done as "all-up round system engineering and programmatic activities to align and phase the work necessary to design, develop, integrate, test, and verify component and subsystem design changes to the JASSM-XR baseline electronics, hardware, firmware, and operational fight software."

The Air Force switched from baseline JASSMs to JASSM-ERs several years ago, and has produced more than 2,000 of the longer-ranged weapon so far. The Air Force was unable to comment on how many ER models might be uprated to the XR configuration or when the change would be cut in at the production line in Troy, Ala., but the contract said that all XR-related development and test is to be completed by Aug. 31, 2023.

http://www.airforcemag.com/Features/Pages/2018/September%202018/Lockheed-Martin-Developing-Extreme-Range-JASSM-Variant.aspx

Wikipedia: AGM-158_JASSM#JASSM-XR

In September 2018, Lockheed Martin was awarded a contract to develop an "Extreme Range" variant of the AGM-158. The weapon would weigh about 5,000 lb (2,300 kg) and deliver a 2,000 lb (910 kg) warhead out to a range of 1,000 nmi (1,900 km; 1,200 mi); it is planned to be ready by 2023.

So it is in development. But at over twice the weight of the JASSM-ER, it seems certain that the fuselage has been stretched, both for a doubling in weight of the warhead (1000lb -> 2000lb), and presumably a doubling in fuel carried, seeing how the range has increased from 575mi (JASSM-ER) to reportedly 1000mi (JASSM-XR).

marauder2048 · by **marauder2048** » 27 Feb 2019, 00:34

The problem is that the budget documents don't really support connecting the current
XR effort to the previous XR concept. Example: the only warhead variant they've
discussed is a smaller warhead
.
And the amounts budgeted don't suggest it's the practically new missile that the XR concept was.

squirrelshoes · by **squirrelshoes** » 27 Feb 2019, 05:05

marauder2048 wrote:If only straight line range could be converted into something else useful like say loiter.

I'm sure one can dream up instances where loiter would be useful, but is it really something likely to be a priority for a heavy long range weapon with a 2000 lbs warhead?

It isnt like you'd launch it hoping a juicy truck drives by near the target area to go terminal on, you're using it to hit something static at known location in non-permissive airspace.

marauder2048 · by **marauder2048** » 27 Feb 2019, 09:47

squirrelshoes wrote:
marauder2048 wrote:If only straight line range could be converted into something else useful like say loiter.

I'm sure one can dream up instances where loiter would be useful, but is it really something likely to be a priority for a heavy long range weapon with a 2000 lbs warhead?

IIRC, Lockheed proposed two loitering versions of JASSM: a miniature version for F-35 carriage
and a mod to JASSM-ER.

Where's the program element for the 2000 lb warhead?

squirrelshoes wrote:It isnt like you'd launch it hoping a juicy truck drives by near the target area to go terminal on, you're using it to hit something static at known location in non-permissive airspace.

It's not like an adversary would want to protect their high-value targets with obscurants or
have imprecisely located targets that require a non-emitting high-resolution seeker to find.

squirrelshoes · by **squirrelshoes** » 28 Feb 2019, 15:34

marauder2048 wrote:Where's the program element for the 2000 lb warhead?

Sorry brain scrambled 2000 lb missile and 1000 lb warhead when typing.

squirrelshoes wrote:It's not like an adversary would want to protect their high-value targets with obscurants or
have imprecisely located targets that require a non-emitting high-resolution seeker to find.

So what high value targets are imprecisely located that would then be located by a missile flying in slow circles loitering, as opposed to finding upon ingress?