AEDC's largest aircraft model ready for future testing

  • Published
  • By Philip Lorenz III
  • AEDC/PA
ARNOLD AIR FORCE BASE, Tenn. --  An ongoing store separation test on "smart weapons" from the bomb bay of a new 10-percent scale B-52H model in AEDC's 16-foot transonic propulsion wind tunnel (16T) rightly has the attention of test engineers.

Prior to the test, all eyes were on AEDC designers, schedulers and machinists as they shepherded the B-52H Stratofortress model through concept drawings to fabrication to assembly, all in record time.

As the model came together, Doyle Veazey, the ATA store separation section manager, and Don Arrowood, the project's B-52 Program Office/SEEK Eagle Office engineer, were already considering what the future holds for the latest test asset.

"The intent was once it's built we can use it for multiple tests in the future," Veazey said. "We've had inquiries over the decades to do wind tunnel testing on the B-52. This [B-52H model] is really a success story."

Arrowood said having a ground test model of this scale, especially at this time, opens the door to future testing that is long overdue.

"In today's fiscal environment it's essential to perform risk reduction early in the acquisition strategy," he said. "The scope of the internal weapons bay upgrade includes additions of a multitude of weapons that have previously not been released from the B-52 bomb bay."

Arrowood said it was decided that computational fluid dynamics (CFD) and wind tunnel testing would be used to develop accurate weapon release data.

"This data will be validated during flight testing," he said. "AEDC, having a historical background on 10-percent-scale models, was gracious in accepting this high visibility concurrent model design and testing program. It was a rapid development, and AEDC took it on."

Arrowood said AEDC stands out for another reason - if the center's personnel and test facilities had not been available for these projects, the road ahead would have been challenging.

"Currently there are very few wind tunnels that have the capability of housing the 10-percent B-52 model," he said. "According to the B-52 SPO's (System Program Office) current knowledge, the only facility that is capable of performing this level of simulation [in the U.S.] is the AEDC 16T wind tunnel."

Arrowood explained the mission requirements driving the program.

"By developing a wind tunnel model and CFD model, we'll be able to accurately model the bomb bay's aerodynamic environment, as well as external stores' environment," he said. "These models allow for a reduction in test assets for most programs down the road.

"For instance, if a new weapon is developed and has a significant change to an outer mould line, compared to currently certified weapons, the B-52 SPO (System Program Office) can reuse the B-52 model and the new weapons model utilizing wind tunnels and wind tunnel data. From that [data, we can] determine aerodynamic loading of the weapon, jettison loading of the weapon and that information will be used in conjunction with CFD."

Arrowood said the time and money saved through the process is cumulative.

"The CFD then provides accurate release modeling; once that's done it will reduce the total number of assets that will be required for separation testing," he said. "That's the big ticket item - new weapon assets are highly expensive and typically we may need seven [to] eight weapons for releasing to verify modeling data and a real world environment."

Arrowood said the availability of the B-52 Program and SEEK Eagle Office's model and subsequent ground testing at AEDC would have far-reaching effects beyond significant cost and schedule savings.

"From a risk standpoint, if we find a problem early in this or a later stage; [for instance] if a weapon has unexpected characteristics when it comes out of the bay or off of the wing, we now know that for flight testing. We can include it in our risk analysis and provide that to the flight test community, informing them of that risk or possibly even putting it into our tech orders that this asset isn't allowed to be utilized from this location."

Regarding the B-52H model, he noted, "The time line was quite aggressive. This required extreme accuracy in the model design and fabrication. The professionalism has been outstanding. The parts have been delivered with no modifications being required after quality verification. The surface roughness and interference of the parts has been spot-on. As you can see from the model pictures, the scale model is a fantastic representation of the B-52 in-flight."

Looking toward future store separation testing with the model at AEDC, he said, "We will be coming back for phase 1.2 in January to do more testing and I imagine that some time in 2012 we will come back for increment 2."