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DATE:04/11/10
SOURCE:Flight International
PICTURE: Air Force tests 8-blade propellers for legacy Hercules
By John Croft
The US Air Force is nearing the end of a flight test program to measure the performance of Hamilton Sundstrand eight-blade NP2000 composite propellers for the C-130.
Since May, engineers with the 418th flight test squadron have been testing a C-130H3 with the propellers at Edwards Air Force base, most recently completing minimum control airspeed tests.
The NP2000 propellers replace the legacy C130's four-blade propellers, increasing thrust at takeoff and in the low-speed regime whilst decreasing noise and vibration.
Newer C-130Js use a six-blade R391 composite propeller built by Dowty Aerospace.
IMAGE ©US Air Force
The air force in part would like to use such an upgrade for its LC-130 aircraft flying missions to Antarctica, where currently jet-assisted takeoff (JATO) bottles are used to decrease takeoff distance.
Depending on the final performance, the NP 2000 could either reduce the number of JATO rockets needed, or eliminate the thrust augmentation system altogether.
After maximum combat-load takeoffs, three-engine departures and other tests, the air force will reinstall the cargo aircraft's four-blade propellers to directly compare performance characteristics, say officials.
Testing is expected to be finished in January, after which the air force will evaluate whether to upgrade a subset of legacy C-130s with the propeller.
The enhancement is similar to what commercial developer Snow Aviation International has been offering for several years for the C-130E and H models.
Snow says the NP2000 propellers reduce the C-130's takeoff run by more than 20%.
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