|Quoting N8076U (Reply 54):|
According to the theory, a 747 is also "less safe than it could be" in its present design than if it had 6 or 8 of its current engines with 6 or 8 reversers, as it could possibly stop a little faster.
Who said anything about 6 or 8 engines on a 747? That is not my contention (or "theory") and never was. I won't repeat the whole argument again, but summarising: if you have reverse thrust it should be on all engines if at all possible. It was not about having extra engines just in case.
I accept that the lower Vref argument is a big safety factor, but what about circumstances where some or all the flaps cannot be deployed, raising landing speed? As I have said, it's about combinations of problems and circumstances, not single failures.
Yes, early JT9Ds had core reversers, but with the fan reverser only at least the total net thrust on each engine is negative. The core reversers added a small proportion of reverse thrust for a lot of extra complexity.
|Quoting Zeke (Reply 52):|
In my view no additional wiring would be needed for this, as far as I understand just about everything on the aircraft is done on a bus, the reverse logic and monitoring would be just additional data on the bus.
You might be able to add the reverser data to existing buses to the FADECs. However some non-bus connection is almost inevitable, so additional wiring would probably be necessary to install the reverser control and indication signals.
Even if no wiring were involved, it certainly would not be a trivial matter to install outboard reversers as a customer option, unless the aircraft had been provisioned for outboard reversers all along. Airbus aircraft are much less customised than Boeing, for example, so I doubt Airbus would consider the idea, unless all aircraft were to be modified.
The glass isn't half empty, or half full, it's twice as big as it needs to be.