John wrote:
On Jan 24, 10:27 am, kT wrote:
I was just thinking it might be wise to put a fifth small turbofan,
something like a Williams International, above the pylon, just in case.

I'm assuming this thing can just about glide anywhere, but I'm wondering
how well this thing flies with multiple engine outs. Since they will
presumably have paying passengers in this thing, a small pusher fan
might be in order. Those main engines seem pretty powerful for that.

Anybody have any idea how something like this might handle with a single
engine, and almost empty on fuel?

The rendering I saw showed four engines on White Knight II. The
chances of losing all four engines is really low (note I did not say
impossible or incalculably low).

Two engines out on the old Boeing 707 (and presumably the current
similar KC-135) was said to be very interesting when both engines were
on the same side. I wonder if anyone could lend insight into how the
747, Airbus 340, or Airbus 380 handle with two out on the same side.
There are tales of a 707's and DC-8's landing with only one engine.
But there are also stories of how airline crews were killed on
training flights (without passengers) practicing for some of these
scenarios back in the pre-simulator days.

You have to weigh the cost of the additional weight and complexity
versus the value a 5th engine would bring if needed. I suspect
numerically, it might not work out.

This vehicle in no way compares to a conventional airliner.

I can see no way this thing can fly with asymmetric thrust, but I'd be
happy to be proven wrong on that. I'm pretty sure that's why they went
with four engines in this manner, besides the obvious thrust levels.

Like I said, I'm sure this thing can glide back no problem, but they'd
have to dump a lot of fuel into the environment to do it. It would be
interesting to see what kind of abort profiles they are anticipating.