The GAU-22/A thread

[popcorn]

They seem to have isolated the cause and it should be just a matter of prioritizing a fix.

[kimjongnumbaun]

In the AH-64 the targeting computer aligns the boresight of the bushmaster. I expect that aligning the gun in the F-35 would not be significantly different but it does require a few runs at the range.

[sprstdlyscottsmn]

In the AH-64 the targeting computer aligns the boresight of the bushmaster. I expect that aligning the gun in the F-35 would not be significantly different but it does require a few runs at the range.

There is a huge fundamental difference in that the bushmaster is a gimballed weapon.

[steve2267]

In the AH-64 the targeting computer aligns the boresight of the bushmaster. I expect that aligning the gun in the F-35 would not be significantly different but it does require a few runs at the range.

On the other hand, it may be as simply as fitting a laser pointer engineered to precisely fit in the breach of the GAU-22/A, co-aligned with the bore, and then note where the little red (or green) dot appears on a calibrated target a known distance from the aircraft. With suitably precise survey equipment, you could measure some key points on the airframe, and on the target, and then compute the necessary slop, errr kentucky windage factors, errr... airframe specific GAU-22/A installation-aiming parameters which get fed into the sighting system.

If after a few gun runs... if problems still exist... re-examine & come up with plan 9.

[chrisben]

Extreme precision is not necessarily a quality in itself, specifically in A2A. You want some dispersion.

[wrightwing]

Extreme precision is not necessarily a quality in itself, specifically in A2A. You want some dispersion.

True, but if firing danger close, you want a pretty good idea where that dispersion is going to be.

[steve2267]

Extreme precision is not necessarily a quality in itself, specifically in A2A. You want some dispersion.

I believe the dispersion is built-in to the GAU-22/A itself. The fact that the F-35B and F-35C gun pods are meeting contractual requirements tells me that the dispersion is fine. (UNLESS the gunmounts in the F-35A are loose or wobbly, which, somehow, I doubt.)

That suggests to me, and I believe some statements made in the quoted articles earlier, the issue in the F-35A is that when the gun was installed, it was somehow not identically and precisely aligned in the aircraft. But since reporting on this issue is sparse, and dubious (or just flat poor) at best, it is hard to know exactly.

[wolfpak]

It could be that the brackets the gun mounts to in the "A" allow for more flexure of the gun barrels throwing off accuracy. Might need to stiffen the brackets. Barrels move around a bit and I believe that was part of the problem on the 30mm on thee AC-130. In any event the manufacturer of a new 40mm weapon added 4 tapered splines to the barrel of it's gun to reduce flexing.

[spazsinbad]

Rheinmetall Supplies Ammunition for USAF F-35s: Working to Expand to RAAF
26 Feb 2019 SLDinfo

"...25mm x 137 Frangible Armour Piercing (FAP)… [described from earlier sources]

...In an article by Andrew McLaughlin published in the Australian Defence Business Review on February 25, 2019, the efforts of the company in Australia were highlighted. Rheinmetall Defence Australia has offered a new 25mm munition specifically designed for the F-35 Lightning II JSF to Australia.

Rheinmetall says the 25mm frangible armour piercing (FAP) ammunition designed for the F-35’s GAU-22/A gun is already in service with the USAF with the PGU-48/B designation. It offers superior lethality against air and ground targets by combining high penetration performance, versatility, reliability, low dispersion and handling safety....

...The FAP round was specifically developed by Rheinmetall for NATO F-35 operators to provide a non-depleted uranium and non-high explosive cartridge with superior lethality against armoured vehicles at extreme slant ranges, while still remaining effective against aircraft in air-to-air engagements."

Source: https://sldinfo.com/2019/02/rheinmetall ... d-to-raaf/

[steve2267]

The last time I recall the F-35's gun being in the news was June 2019, and if memory serves, Valerie Insinna in her David Axe guise, was ripping on the F-35A for a gun inaccuracy issue. But I've seen no further peeps from the press on the GAU-22/A and it's accuracy (or not). Since the press seems to love to rip the F-35 program every chance it gets, this lack of continued reporting on the matter suggests to me that the issue has been fixed or resolved. Does anyone have knowledge of such a fix, or has anyone seen any such articles reporting the gun accuracy issue as having been resolved?

[marsavian]

The Gun On the Air Force's F-35 Has 'Unacceptable' Accuracy, Pentagon Testing Office Says

https://time.com/5774422/f-35-military-jet-assessment/

The 25mm gun on Air Force models of the Joint Strike Fighter has “unacceptable” accuracy in hitting ground targets and is mounted in housing that’s cracking, the Pentagon’s test office said in its latest assessment of the costliest U.S. weapons system.

The annual assessment by Robert Behler, the Defense Department’s director of operational test and evaluation, doesn’t disclose any major new failings in the plane’s flying capabilities. But it flags a long list of issues that his office said should be resolved — including 13 described as Category 1 “must-fix” items that affect safety or combat capability — before the F-35’s upcoming $22 billion Block 4 phase.

The number of software deficiencies totaled 873 as of November, according to the report obtained by Bloomberg News in advance of its release as soon as Friday. That’s down from 917 in September 2018, when the jet entered the intense combat testing required before full production, including 15 Category 1 items. What was to be a year of testing has now been extended another year until at least October.

“Although the program office is working to fix deficiencies, new discoveries are still being made, resulting in only a minor decrease in the overall number” and leaving “many significant‘’ ones to address, the assessment said.

The Air Force and Navy versions are also continuing to have cracks in structural components, according to the report, saying, “The effect on F-35 service life and the need for additional inspection requirements are still being determined.”

The three F-35 models are all equipped with 25mm guns. The Navy and Marine versions are mounted externally and have acceptable accuracy. But the Air Force model’s gun is mounted inside the plane, and the test office “considers the accuracy, as installed, unacceptable” due to “misalignments” in the gun’s mount that didn’t meet specifications.

The mounts are also cracking, forcing the Air Force to restrict the gun’s use. The program office has “made progress with changes to gun installation” to improve accuracy but they haven’t been tested yet, according to the report.

[sprstdlyscottsmn]

so, old news

[marsavian]

I didn't know the mounts were cracking. What are the structural problems in the 'Navy' version which doesn't have the internal gun.


p.s. more non gun-related info at the link.

[marauder2048]

DOT&E report FY19 (JSF)

https://www.dote.osd.mil/Publications/Annual-Reports/2019-Annual-Report/

[spazsinbad]

I'll guess dis inaccurate gun may get dis toot sweet. DEATH CLAW 3 page PDF attached.

Death Claw Shows Path to Faster Development
Steve Trimble AVIATION WEEK & SPACE TECHNOLOGY/JANUARY 27-FEBRUARY 9, 2020

"...“Flight tests showed aircraft-pointing accuracy improves significantly when Death Claw is engaged (see graphic below) compared to pilot control.”...

"A 40-year-old idea to improve strafing accuracy by transferring flight control of a manned fighter to the autopilot to aim the gun is being revived as the U.S. Air Force looks internally for innovations that can
be demonstrated and delivered quickly.

An operational version of the Digitally Enhanced Aiming Through Control Law (Death Claw) system is in
development less than two years after the U.S. Air Force Test Pilot School conceived and performed an eight month demonstration.

In effect, Death Claw has two functions. As a new automated flight mode, it solves a practical problem for pilots of F-16s and potentially other flyby-wire fighters. The system also highlights a path to introducing aircraft upgrades faster by involving the test community up front.

The practical problem has been known for decades. Like any modern fighter, the F-16’s sensors and flight computer can precisely calculate where the F-16 needs to be pointed for the 20-mm rounds from the fighter’s M61 cannon to hit a moving target in the air or on the ground. But the computer still relies on the human pilot to accurately point the aircraft at the spot indicated on the gunsight-pipper on the head-up display.

The answer seems obvious. Add an “auto-gunnery mode” to the flight control law, and allow the autopilot control to point the aircraft when the gun is engaged. Bill Gray, chief test pilot of the test pilot school, launched a demonstration program in late 2017 to prove it could work.

...“To a P-51 pilot, the gun was precise, it was your precision. Well, now the gun is the least precise weapon on the F-16,” Gray says. “Death Claw was basically a project to make the gun a precision weapon.”..."

Source: https://aviationweek.com/defense-space/ ... evelopment
from page 29 of the AvWeak FREE PDF online: https://aviationweek.com/sites/default/ ... 0127_0.pdf (8.5Mb)