Chasing a Falcon

[Old Viper Tester]

The 6512th Test Squadron, aka "Test Ops", at Edwards AFB was responsible for providing test support to the major test teams under the 6510th Test Wing.  While a test team like the F-16 Combined Test Force 'owned' their own test pilots and test aircraft, Test Ops provided support aircraft and crews as required. In the 1980s, Test Ops aircraft were primarily A-7Ds, A-37Bs, NKC-135s (often on detachment from the 4950th Test Wing at Wright-Patterson), various models of the F-4, and T-38s. Test Ops also performed what was referred to as 'Cats 'n' Dogs' testing. Usually small test programs that didn't warrant creating a large, dedicated test force. The HU-25B was one of these test programs, sponsored by the US Coast Guard.

 

The original HU-25 flight testing was performed by Dassault, certification for the USCG relying heavily on the FAA certification of the Falcon 20 biz jet, from which the HU-25 was derived. Addition of mission pods is not normally covered by the FAA, so when the HU-25B was proposed, a separate test program was required to cover the effects of carrying Side-Looking Airborne Radar and other sensor pods under the wings and fuselage was required. The program was assigned to Test Ops in 1983. The aircraft provided (2118) was fitted with special instrumentation to collect data for aircraft performance, flying qualities, and structural loads.

 

I got to participate as a safety chase observer for one of their missions in May 1983...

 

2118 with a Yaw and Pitch sensor nose boom installed. The silver strips at the base of the vertical tail are strain gauges covered with silver "speed tape". That big pod mounted under the forward fuselage decreases the lateral stability of the aircraft, thus the vertical tail might work harder to keep the aircraft on its intended path. The nose legend reads "EDWARDS" beneath the aircraft number.

 

 

 

The left side view show additional speed tape covering the wiring and sensors to measure rudder hinge loads.

 

 

They also did an icing test for the pods at some point...

That's NKC-135A, s/n 55-3128, the long serving icing tanker. '128 belonged to the 4950th Test Wing, which is why it carried the Aeronautical System Division (ASD) blue tail band outlined in yellow. The aircraft could still serve as a refueler, but it had its plumbing modified so that a fuselage fuel tank could be isolated and filled with water. A control station was installed to vary pump speed/droplet size. A spray ring is installed at the end of the refueling boom - installation similar to fitting a refueling drogue. The water contained dye for better visualization of ice build-up, hence the yellow ice adhering to the sensor  pods.

 

As for 2118, when the test program was over, the flight test instrumentation was removed and the aircraft eventually found its way to the Sacramento USCG station. It's since been retired and is now in the Aerospace Museum of California.

 

Thanks for looking,

Sven

 

Edited January 3, 2018 by Old Viper Tester
typos

[Red Dot]

Brilliant stories and photos as ever, thanks

 

Andy