Same reason that the F-2 got rid of the traditional F-16 canopy and put in a reinforced forward windscreen... bird strikes. Big bird strikes in specific. The F-2 replaced the F-1 as the JASDFs primary low altitude strike and anti-shipping aircraft. Large sea bird impacts being a serious concern in that role.miljan wrote:I was always wondering why they go with 4 engines?
For the P-1, the Japanese went with a different design theory path than the Americans did with the P-8. The P-8 represents a fundamental shift in ASW operations with an aircraft optimized for operations at medium altitudes with wings, engines, sensors and weapons delivery profiles optimized for that new operational theory. The P-1 on the other hand represents modernization of technology to continue the mission of the P-3. If you look at the P-1 in comparison to the P-8, it has a straighter, thicker wing optimized for low altitude low speed flight. It is also reportedly a more agile aircraft with gigantic windows for low altitude observation. The P-1 retaining a MAD boom while the P-8 no longer has one being another design choice pointing to the different philosophies regarding ASW tactics.
That's a long way of saying that the P-1 will be expected to spend a lot more time on the deck than the P-8, so bird strikes are a bigger concern.
The Japanese are apparently continuing an old P-3 tradition in the P-1. Using all four engines to sprint at high speed to the patrol area then throttling back two of them to improve loiter time once on station.
Also of note, the P-1 does not have provision for in-flight refueling. But then again, the P-3 never did either.