The Viper's Heterogeneous Intakes
Most people aren't aware that the iconic F-16 utilizes two dissimilar types of air intakes, each correlated with the specific Block of the aircraft. The original intake as fitted to all jets powered by the Pratt & Whitney engines have the NSI (Normal Shock Inlet), or "Smallmouth" intake. These aircraft include Block 25, 32, 42, 52 and 72 models. They can be distinguished by a more rounded intake opening.
MCID Intake found on the GE-powered birds (Below)
When the General Electric engine was first fitted on Block 30 models, it was soon realized that this engine required more air than the Pratt & Whitney engine. To increase the airflow, the intake was widened at the opening, resulting in the MCID (Modular Common Inlet Duct), or "Bigmouth" intake. This intake first appeared on F-16D 86-0044 and F-16C 86-0262. All previous Block 30s have the NSI intake, while all subsequent Block 30, 40, 50 and 60 aircraft have the MClD intake. The MCID intake can be distinguished by a much larger opening than the NSI.
Another distinctive trait is the angle of the ECS (Environmental Control System) scoops at the top of the intake. On the NSI intake, these scoops are vertical, though on the MCID; angled (above photo).
© cactusbillaz
GE Motor (Left) PW Motor (Right)So how do you even identify the different blocks from one another? Start off with the exhaust nozzles, those are an easy way to tell the engines apart. A longer more straight nozzle would be the PW F100, as the GE F110 has a shorter more curved nozzle. Besides, if you ever happen to hear the jet swoop over, the PW motors have a characteristic "zipping" noise when the throttles are moved because of the air-motor they use to power the nozzle actuators, which are mechanical. The GE nozzle, on the other hand, is hydraulic and does not make as much of a noise when it's moved.
All in all, blocks ending in "0" are powered by General Electric, whilst blocks ending in "2" are fitted with Pratt & Whitney engines. Consequently, PW-powered F-16s are referred to as 'small-mouth' just as GE-powered F-16s would be 'big-mouth'.
Since the article would have been incomplete without a sweet picture of the Viper ;)
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ReplyDeleteSo, the second block of Navy F-16Ns were formerly USAF 86-1684/1695. Does this mean that F-16Ns have different intakes depending on the block in which they originated? Or did the Navy standardize on the small intake?
ReplyDeleteSo in the picture with the two types of intakes seen from the front, which is the NSI, and which is the "Big Mouth"? The text is unclear on that point.
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