Alain Fournier wrote on Tue, 13 Mar 2018
17:01:07 -0400:

On Mar/13/2018 at 5:53 AM, Jeff Findley wrote :
In article ,
says...

On 2018-03-12 20:37, Alain Fournier wrote:

Elon Musk said at South by Southwest that his Big Falcon Rocket
would start doing small test flights early next year.


"small test" ? a 1m high scale model with a tank of diet coke into which
a Mentos candy is dropped? :-)


Space-X apparently has begun to test its new Raptor engines.

For commercial aircraft, they can mount a new engine on a 747 and test
it in flight. (same fuel, and sufficiently spaced pylons make it
possible to mount new engine)


What are Musk's options to test fly the new engines?

BFS. It could be that the first BFS would be similar to Grasshopper or
Enterprise in that it won't have all the systems necessary for
supporting a crew in space. Automated testing only.

In
https://www.theregister.co.uk/2018/0...xsw_interview/
it isn't quite clear whether the test if for BFR or BFS. But I'm not
sure if you are stating as fact that it will be BFS or if that is
just your guess. So do you know that it will be BFS or do you think
it will be BFS.


Looking it up, Musk said, “I think we might be able to do short hopper
flights with the spaceship part of BFR, maybe next year. By hopper
tests, I mean kind of like the beginning of the Grasshopper program
for Falcon 9... it will go up several miles and come down."

So that should be the end of all speculation.

Can they built a Falcon-9 with a few raptor engines and a methane tank
instead of Kerosene for a test flight?

No, not without significant engineering, which would be a complete waste
of time and money.

Or must one assume that a test flight will be raptor engines on a BFR
stage 1 (even if it is topped by a cone instead of stage 2) ?

I believe BFS will be tested first. It has fewer engines than BFR.
Also, it might even have SSTO capability by itself without much payload
of course.

I would be very surprised if BFS had anything close to SSTO capability.
It is a spaceship not a launch vehicle.


It is both. Musk has stated that BFR Spaceship is capable of SSTO
operation, but only with small payloads. Remember, this thing is not
JUST a spaceship. It is designed to land on both Earth and Mars and
to take off powered from Mars and return to Earth. It is also
intended to be able to do transcontinental flights with large
payloads.


If they do just a little hop with BFR or BFS, I would call that just
a small test. But I'm not if it should be called a small ****ing test
or what :-)


The 'little hop' will apparently be on the order of several hundred
kilometers up and sideways and then return.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw