B-52 undergoes HERO testing

A B-52 from the 96th Bomb Squadron, Barksdale Air Force Base, is at the Benefield Anechoic Facility at Edwards AFB. Due to a recent mandate from the Air Force Safety Office, a B-52 was required to undergo Hazards of Electromagnetic Radiation to Ordnance testing. The BAF is the largest anechoic chamber in the world, capable of taking any size aircraft into it for testing.

The B-52 was flown in from Barksdale, and was placed into the BAF over four days. Once it was inside the building, a maintenance crew from Minot placed it on jackstands on a turntable inside the building, the gear was retracted and it was rotated 180 degrees. A loaner OSO and DSO crew member are there to operate onboard systems, along with EW personnel from Eglin AFB, Boeing, and local personnel. There is no ordnance involved, with readings being taken in the areas the ordnance would be located. This allows them to determine if the weapons are capable of functioning properly without inadvertently being activated by electromagnetic radiation from outside the aircraft. The weapons will be declared as one of the following categories: HERO Safe, HERO Susceptible, or HERO Unsafe.

EDWARDS AIR FORCE BASE, Calif. (AFNS) -- A B-52 Stratofortress from the 96th Bomb Squadron at Barksdale Air Force Base, Louisiana, is undergoing Hazards of Electromagnetic Radiation to Ordnance testing in the Benefield Anechoic Facility (BAF) here.

The test was requested by the B-52 Program Office at Tinker AFB, Oklahoma, to comply with a recent mandate from the Air Force Safety Office according to members of the 772nd Test Squadron who oversee BAF operations. The mandate states all Air Force weapons platforms will conduct Electromagnetic Environmental Effects evaluations. This test with the B-52 concentrated on the HERO element.

Ordnance and other devices that contain electro–explosive devices must function in their operational electromagnetic environment without inadvertently activating. To prevent the susceptibility of ordnance to radiated or conducted electromagnetic energy, HERO limits are imposed. HERO tests are conducted to classify the ordnance's susceptibility to electromagnetic radiation as HERO Safe, HERO Susceptible, or HERO Unsafe.

“The advantage of using the BAF chamber allows for more sensitive measurements with low background noise levels, as compared to testing on the flightline where there are numerous interfering radio frequency sources,” said Hannah Dahlgren, the 772nd TS project lead engineer. Since no signals escape the chamber, the customer does not have to deal with regulatory clearances to radiate from the aircraft, which typically results in transmitting late at night only to avoid interfering with flightline and commercial operations.”

www.af.mil...

I hope the HERO test goes well.

We all need a hero.

I'm confused, isn't an anechoic chamber a sound isolated chamber that basically is a sound vacuum? What bearing does sound have on radiation?

Nevermind...I just reread and answered that myself. I would have never thought about using one for this purpose, but it makes sense.

Interesting to say the least. I know they test airframes for EMP out in New Mexico, but I never thought about testing the weapons themselves on the air frame.

It would be interesting to see the differences between external and internal weapons.

a reply to: FredT

Yeah it would be. Obviously there would be differences, but I'd be really curious how much difference the airframe makes.

a reply to: RickyD

They really hammer them with EMI in the chamber. The X-47B was hit with something like 2,000 times the maximum level measured on a carrier deck.

originally posted by: Zaphod58
a reply to: FredT

Yeah it would be. Obviously there would be differences, but I'd be really curious how much difference the airframe makes.

Im curious myself. Given that planes can withstand a lightning strike (4-5 billion jules) I wonder if the frame acts as sort of a default faraday cage and routes the energy around the internal weapons?

originally posted by: FredT
Interesting to say the least. I know they test airframes for EMP out in New Mexico, but I never thought about testing the weapons themselves on the air frame.

It would be interesting to see the differences between external and internal weapons.

RF is such magical crap that you generally have to test the sub-assemblies and the complete system separately.

We usually have to do RF susceptibility at the unit level, say, a flight monitoring system that goes in a fighter's spare nooks somewhere for post-analysis of performance. Then you have to do the whole thing. Because the system integration changes the behavior of the individual unit assemblies.

The Navy used to use a floating EMP tester called EMPress. I don't know what's up with them these days. I know EMPress II was husky enough that it killed at least one guy who got left on deck.

originally posted by: FredT

originally posted by: Zaphod58
a reply to: FredT

Yeah it would be. Obviously there would be differences, but I'd be really curious how much difference the airframe makes.

Im curious myself. Given that planes can withstand a lightning strike (4-5 billion jules) I wonder if the frame acts as sort of a default faraday cage and routes the energy around the internal weapons?

SORT of. It depends on the frequency distribution of what you're getting popped with.

A nuke's prompt phase mostly has its energy below 30MHz, so it's pretty long, comparatively. So a fairly big gap is still 'sealed' to nuke EMP output. But a HPM attack from an AESA set on 'kill' will go right through. So it depends on what you're trying to guard against.

a reply to: Bedlam

Wouldn't be the mechanical stress of a lightning strike do the most damage initially; Nothing an intermittent bank of hf resistors and capacitor trimmers can't handle plus some transistors courtesy of our reverse engineering? #ing interesting though you know like if a plane could survive a lightning strike would it charge its battery's? Star and flagged because redirection of energy is sexy.

a reply to: BeneGesseritWitch

No, it won't charge the batteries. It does fairly minor damage to the aircraft as well. We changed the radome on a C-5 that got hit by lightning. The entry hole was about the size of a quarter, on the outside of the radome, and the inside had a spot about the size of my fist, where it exited the radome. It went out under the base of the tail, and there was very little damage there as well.

you probably knew it was the size of a quarter cause you tig welded one in there to fix it, I figured the exit one would be bigger but seriously a quarter is nothing... a cool breeeze really.