Boeing NT-43A Radar Test Bed, 73-1155 aka 'Bill Clinton Airplane'

flateric

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Have found a nice photo of this quite sensitive bird, so have decided to collect bits from the net to post here for a reason.

The Air Force operates a modified NT-43A as a Radar Test Bed (RTB) with radar imaging gear on its nose and tail in radomes that are 9 feet long and over 6.5 feet in diameter. NT-43A Radar Test Bed, 73-1155 making radar images of a Northrop-Grumman B-2 Spirit at an altitude of about 7,000 feet over Death Valley on January 24, 2003. Death Valley is utilized as a natural radar test facility. It is over a mile deep and a hundred miles long, shielded from all radar transmitters, providing an environment free from radar interference.
The RTB is used to make radar images of stealthy aircraft. The images are used to evaluate the effectiveness of their stealth characteristics, to reveal the rate of degradation of the radar deflecting and absorbing components as the aircraft age, and to determine the effectiveness of maintenance and repair methods.
NT-43A, 73-1155 carries Boeing construction number 20702. It first flew on July 2, 1974 and was delivered to the Air Force ten days later. It served initially as a navigation trainer. It was retired from that role and delivered to AMARC on September 25, 1997. Identified as TH002, it was sealed with spraylat and sat in the desert sun for over two years. 73-1155 was selected for modification as the Radar Test Bed. It was pulled out of storage at AMARC and delivered to the Ogden Air Logistics Center (OO-ALC) at Hill Air Force Base, Utah for refurbishment on November 19, 1999.

73-1155 was flown to an aircraft maintenance and modification facility at Goodyear, Arizona in March 2000 for the installation of the enormous radomes on its nose and tail.

DENMAR, Inc. was the prime contractor for the modification of the NT-43A. It is run by Denys Overholser, who wrote the "Echo 1" software used to evaluate the stealth characteristics of the Have Blue and F-117A Stealth Fighter. Under contract to DENMAR, Inc., the Lockheed Skunk Works designed and fabricated the mounts for radar installations on the nose and tail (see attachment) of the RTB at Air Force Plant 42 on the grounds of the Palmdale Airport in California. The mounts are made primarily of carbon epoxy honeycomb sandwich with machined aluminum fittings. They are 16.5 feet long and 6.2 feet in diameter. After conversion, it was rolled out on February 22, 2001. Its first flight in its new configuration was flown on March 21, 2001.
The flight operations contractor for the NT-43A is EG&G, operator of the "Janet Airlines" 737s and former T-43As that are used to transport workers to and from secure facilities in the Nellis AFB ranges. The lack of public sightings of the RTB suggests that the NT-43A operates from one of those secure facilities. It was sighted inside a hangar at Goodyear in December 2004, but otherwise it is rarely seen.

In mid-2000 the Lockheed Martin Advanced Prototype Center, part of the Advanced Development Programs' (ADP) organization, handed over its first major deliverable -- a flight-worthy composite structure -- on the center's first design and fabrication contract. The structure, a 19-foot long, 6.2-foot diameter fairing and bulkhead assembly, was delivered to customer DENMAR Inc. The prime contractor Denmar is a company specializing in stealth technology. The "Den" stands for President Denys Overholser, the former Skunk Works engineer credited with devising the shape of the first stealth aircraft. The assembly provides an aerodynamic transition from the existing aft fuselage of a T-43 aircraft, a modified Boeing 737-200, to an oversized radome. The aircraft serves as a Radar Test Bed (RTB) for future Air Force programs. The design, fabrication and machining of the structure's components were all performed at Palmdale. The structure is made of a 90-percent carbon epoxy/honeycomb sandwich material, with machined aluminum parts, and houses an airborne radar assembly. The contract with DENMAR also included the design and fabrication of three radomes for the RTB aircraft. Each radome is more than 6.5 feet in diameter and 9 feet in length. Technical papers from Rome Lab reference a bistatic Advanced Airborne Surveillance system-originally due to be demonstrated in 2000, and a graphic in a Lincoln Lab briefing paper showed a bistatic radar with its transmitter mounted on a 737. The Advanced Radar Test Bed [ARTB] was based on a Lockheed NC-141 (tail number 61-2779).

TRANSPORT AIRCRAFT TECHNICAL SERVICES COMPANY, INC.
...a highly modified T-43A that was originally deliverved to the USAF as a Navigator trainer.
...what we call the Bill Clinton airplane -- big nose and you know what!) We provided the out-of-storage and pre-modification
work packages and provided oversight on the acquisition of up-graded JT8D-17 engines.

“Bill Clinton” ─ a USAF T-43A (B737-200) radar test airplane with a very large radar on the nose and another one on the tail (a prudent man does not fly head-on to another airplane to “look” at that airplane UP CLOSE!).
 

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To update this thread, 73-1155....well I assume it's that as it has the same radome configuration....was photographed flying out of Tonopah the first week in November, callsign RAFT55.

I'd better not post the photo here but will try and find a link in case my colleague has uploaded it somewhere.

Ian
 
Spongthrush said:
To update this thread, 73-1155....well I assume it's that as it has the same radome configuration....was photographed flying out of Tonopah the first week in November, callsign RAFT55.

I'd better not post the photo here but will try and find a link in case my colleague has uploaded it somewhere.

Ian

Here:

And it was still there during December. Since 2005 it's been a regular at TTR, though it's not clear if TTR is "home". It may be supporting the RQ-170 program.
 
Brian Lockhart who takes those photos and makes the calendars, has a wealth of aviation history in his photography.


When I was a copilot on Tanker 65, the C-54E in 2004, he photographed us in the air and on the ground, later giving me some photos, we are on the cover of the airtanker calendar.
And later, I was in Santa Barbara flying as Captain on a Short 330, and he photographed the plane and the approach in for landing, and many photos on the ground.


His photos of the NT-43 are some of the very few out there, he just happened to be in the right place at the right time.
 
The NT-43A now has a dorsal radome ...
 

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Here's a photo of the NT-43A I've had for a few years but was asked not to share back then. As it is now nearly six years old and I've edited out the people from it I believe it's okay to share it now.

[edit - I've replaced the image with a smaller size version so as to avoid trouble with the photographer]
 

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fightingirish said:
foxtrotalpha - The World's Most Secretive 737 Is America's Key To Better Stealth Tech

Nobody knows exactly where "Rat 55" lives or precisely what technology it uses to accomplish its mission, but it sure is an exotic beast.

Uhhhh.... actually, we do?

RAT-55 was modified by Denmar Technical Services. Since the original set of modifications it has received several sets of upgrades. Denmar also plays a major role in operating RAT-55.

The test asset is based on the Nevada Test and Training Range and regularly operates in several distinct areas to perform in-flight verification and diagnosis of aircraft signature. There are locations in California and Nevada where NT-43 can be seen flying regularly, and there are many photographs of NT-43 over the California location.
 
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Skyblazer said:
Here's a photo of the NT-43A I've had for a few years but was asked not to share back then. As it is now nearly six years old and I've edited out the people from it I believe it's okay to share it now.
Very cool!
 
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quellish said:
fightingirish said:
foxtrotalpha - The World's Most Secretive 737 Is America's Key To Better Stealth Tech


Nobody knows exactly where "Rat 55" lives or precisely what technology it uses to accomplish its mission, but it sure is an exotic beast."
Uhhhh.... actually, we do?

]RAT-55 was modified by Denmar Technical Services. Since the original set of modifications it has received several sets of upgrades. Denmar also plays a major role in operating RAT-55.

The test asset is based on the Nevada Test and Training Range and regularly operates in several distinct areas to perform in-flight verification and diagnosis of aircraft signature. There are locations in California and Nevada where NT-43 can be seen flying regularly, and there are many photographs of NT-43 over the California location.

It's Foxtrotalpha. Like the National Enquirer of military sites.
 
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sferrin said:
It's Foxtrotalpha. Like the National Enquirer of military sites.


It's entertaining to see a new post on an obscure topic on that site (and others) hours or days after a thread on that topic is updated here. I have observed this more than a few times.
 
Skyblazer said:
Here's a photo of the NT-43A I've had for a few years but was asked not to share back then. As it is now nearly six years old and I've edited out the people from it I believe it's okay to share it now.


That's amazing Skyblazer! Thanks for sharing!
 
Now that you guys have seen the photo, I've replaced it with a smaller size version so as to avoid trouble with the photographer. Thanks for understanding!
 
quellish said:
sferrin said:
It's Foxtrotalpha. Like the National Enquirer of military sites.


It's entertaining to see a new post on an obscure topic on that site (and others) hours or days after a thread on that topic is updated here. I have observed this more than a few times.

Yep. The Aviationist and The Brigade have a habit of doing that as well. I posted a picture of that B-1B landing at Edwards with a collapsed nose gear on milphotos.net. The next day The Aviationist had a big article about it. Then others picked it up. The writers at The Brigade troll milphotos for pictures. Many times I've posted somewhat obscure pictures there only to have them show up a few days later on The Brigade. Anyway this is veering OT so I'll just leave it at that.
 
sferrin said:
quellish said:
sferrin said:
It's Foxtrotalpha. Like the National Enquirer of military sites.


It's entertaining to see a new post on an obscure topic on that site (and others) hours or days after a thread on that topic is updated here. I have observed this more than a few times.

Yep. The Aviationist and The Brigade have a habit of doing that. I posted a picture of that B-1B landing at Edwards with a collapsed nose gear on milphotos.net. The next day The Aviationist had a big article about it. Then others picked it up. The writers at The Brigade troll milphotos for pictures. Many times I've posted somewhat obscure pictures there only to have them show up a few days later on The Brigade. Anyway this is veering OT so I'll just leave it at that.


Hi, I'm a long time lurker on this board and follow it only because I'm interested in the subject. Ive found that information from 'regular journalist' sources is sadly lacking, but on this forum you get informed, non-sensationalist insights without the ufo and conspiracy nuts you get in other places. It was websites like The Aviationist and writers like Tyler (foxtrotalpha) who pointed me to this forum.


I was just wondering why you thought them sourcing stories and interest pieces from this forum was a bad thing?
 
Did you see any credentials to SPF for example for the only hi-res NT-43A photo in public access at FoxtrotAlpha piece? I could keep it for my own and never post, for example...
 
Exactly. It isn't hard to mention sources. Professional aviation writers have managed to credit the forum and its posters previously.
 
fightingirish said:

Dear members,
I feel bad for posting that link to foxtrotalpha's website.
I should have written that I had just found that article and posted it quickly while I was surfing on my couch with my tablet. Normally I (should!) analyse these articles and categorise them as primary and secondary sources. Just like as I was teached in basic source studies (ger: Quellenkunde) in a major history class at my high school here in Germany.
My deep regrets to members, reporters and visitors,
who have access to primary sources and post them here in this forum before been published! :)
 
flateric said:
Did you see any credentials to SPF for example for the only hi-res NT-43A photo in public access at FoxtrotAlpha piece? I could keep it for my own and never post, for example...


That's fair enough then, I didn't realise that's what had happened
 
That's because the author reads this site. (I know...Captain Obvious.) But I don't think he participates in discussions.
 
lowchi said:
Posted by reddit user Shmowzow

Link: https://www.reddit.com/r/aviation/comments/3t92cv/just_after_sunrise_i_saw_a_b2_trailing_another/

http://imgur.com/0VoV9hx

RAT-55 flies there pretty often, Death Valley is where they do most of their work. It's controlled airspace and isolated from interference.

RAT-55 has been seen with:
B-2
RQ-170
F-22
F-117
X-47
...And other things.
On one occasion an F-22 was seen with interesting things on the wing stations. Could have been pods, could have been munitions, but they were not on the standard pylons.

It astounds me that "journalists" have not figured out that this is one of the easiest ways to see interesting aircraft under test, most often during daylight. It's not difficult to infer when a test is coming up and go out there.

Protip: If you blur the photo slightly it will become an LRS-B demonstrator.
 
Where was that published?

Bill Sweetman always managed to credit the forum on his blog back at AWST.
 
Whilst I do often enjoy the topics covered by The War Zone, Tyler remains the guy he was at FA. He can't be arsed to credit this forum and will generally ignore any comment or suggestion about it. Joe seems a lot more open to people, maybe someone can trying giving him a heads-up in hopes he nudges his boss.
 
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Hopefully he'll see this thread and feel his cheeks go red from being clapped by embarrassment, but some people cannot get embarrassed. How hard is it to give credit?
 
Reading various threads around the internet about this aircraft it seems there are some misconceptions about what it actually does.

Low observable aircraft are built to RCS requirements and specifications. How do you measure whether the produced aircraft meets the specification?

Mounting the aircraft on a pole for static RCS testing is useful but not always practical and does not reflect what the RCS will be when the aircraft is flying and operational. Flying aircraft have vibrating engines, active antennas, moving parts, and flexing structures which all affect the RCS. The physical and electrical properties of materials also change in flight.

Collecting standard RCS measurements may tell you there is a problem but does not help identify the source of the problem. A polar plot may not be sufficient to identify the individual scattering sources contributing to the RCS.

The NT-43 Radar Testbed (RAT55) carries radars in the nose and tail that not only collect RCS data but also act as diagnostic imaging radars. These radars use inverse synthetic apeture radar to image the scattering sources of the target aircraft. Individual scattering sources are easy to identify. This is what you need to correct any problems in the RCS.

In-flight ISAR diagnostic imaging is performed on low observable aircraft regularly to verify the signature after maintenance, etc.

Below is an example ISAR image of an aircraft.
 

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In those times of political correctness, that thread title is kind of... refreshing. Always make me chuckles when it pops among the new posts.

More seriously - is the aircraft shown in the ISAR a F-106 ?
 
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In those times of political correctness, that thread title is kind of... refreshing. Always make me chuckles when it pops among the new posts.

More seriously - is the aircraft shown in the ISAR a F-106 ?
It is, and you can see individual hotspots that contribute to the frontal RCS
 

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