DSE said:
shockonlip said:
Inspiring!
I wish them luck!!
Thanks DSE!
The key question I think is is the inlet going to start? Quite high contraction and totally axisymmetric with no type of spillage starting mechanism. Just looking down the front is down right scary, imo.
It seems there may be spillage starting mechanism.
In: AIAA 2011-2277 - "The SCRAMSPACE I Hypersonic Flight Experiment Feasibility Experiment"
on pg 3, it indicates that at the beginning of re-entry, at low Reynolds No. the boundary layer on
internal engine surfaces is very thick, and the scramjet will be unstarted, so during descent, an
inlet starting door will be open till when when the Reynolds Number gets large enough for
the inlet to remain started.
Even though this paper is several years old, it seems like the door should still be there.
Although other SCRAMSPACE papers reference novel axisymmetric inlet starting techniques
possibly being deployed.
The inlet seems very sensitive to unstart:
- Inlet started angle of attack seems very tight (within +/- 2 deg).
- And simulations on the inlet, unstarted, depending on what turbulence model was used.
(AIAA 2011-2367 - Numerical Simulation of SCRAMSPACE I Flight Experiment).
Also SCRAMSPACE I measures the reduction in drag as H2 fuel is pulsed on/off as the vehicle
descends from 32km to 27km altitude. In other words the external shape of the vehicle has not
been designed to generate a net thrust, therefore the vehicle is expected to produce a net drag.
Therefore the goal of measuring the change in drag as H2 fuel is pulsed on and off (also measuring
pressure and heat flux through the inlet and combustion chamber).