AtomKraft wrote:My guess,as it would have to something that didn't need fuel, would be a RAT of some type. Don't think it would be too tricky with all that air rushing past.
LTV were given the airframe job, but it was cancelled before the design was finalised.
I disagree with you Atom.
The dynamics of the airflow around a ramjet or scramjet at speeds anywhere betweem Mach 6 and 10 would simply melt protuberences such as a turbine and at the higher end of that scale would begin to cause shock waves that could endanger the integrity of the structure of the aircraft itself. Modern carbon based composites might survive however, but no turbine bearing would endure the loads and temperatures imposed in such extreme conditions for any useful length of time. Another point is that a conventional turbine would operate best in air that it not transonic to avoid tip stalling or overheating etc. and this whole process would be inefficient and problematic in the transonic regime. One has to look at the design of the jet engine and the issues at the tips of the turbines in transonic flows to appreciate that this is a complex aero and thermodynamic area and becomes exponentially more so in high transonic gas flow states.
https://www.southampton.ac.uk/engineeri ... nsfer.page
It is not for nothing that high performance fighters that use(d) a RAT have had an extension speed limit such a noted here in the Phantom F-4 Pilot's Flight Operating Manual.
- Phantom F-4.JPG (24.39 KiB) Viewed 1275 times
You are ignoring the fact that the temperature of the air around an aircraft at the higher end of these Mach scales (Mach 10 and above) begins to cause the formation of a gas plasma and any ingress into the fuselage or a nacelle of ramjet itself would be highly problematic not only due to the shock front development, at even relatively low Mach numbers, but because such points (no matter how small) would represent a weak point in the thermal protection of the aircraft.
I would suggest that any power sources would be internalised and would most likely to be (or have been) gas powered APU's not unlike the ones used in the Shuttle and could even be battery based today.
Using the shuttle as an example again, look what happened when the thermal protection of the aircraft was compromised as in the case of the shuttle Columbia.
As a spacecraft re-enters the earth's atmosphere, it is traveling very much faster than the speed of sound. The aircraft is said to be hypersonic. Typical low earth orbit re-entry speeds are near 17,500 mph and the Mach number M is nearly twenty five, M < 25. The chief characteristic of re-entry aerodynamics is that the temperature of the flow is so great that the chemical bonds of the diatomic molecules of the air are broken. The molecules break apart producing an electrically charged plasma around the aircraft. The air density is very low because re-entry occurs many miles above the earth's surface. Strong shock waves are generated on the lower surface of the spacecraft.
The only manned aircraft to currently fly in this regime are the American Space Shuttle, the Russian Soyuz spacecraft, and the Chinese Shenzhou spacecraft. The figure shows the Shuttle after it has passed through the re-entry regime. The Shuttle uses a rocket propulsion system to get into orbit, but during re-entry the aircraft is actually an un-powered glider. Small steering rockets are used for maneuvering early in the re-entry because the low density of the air at altitudes above 50 miles makes aerodynamic surfaces ineffective. The heat is so great during re-entry that a special thermal protection system is used to keep the spacecraft intact. On the Shuttle, special silicon tiles are placed on the aluminum skin to insulate the skin. On the leading edge of the wings, carbon-cabon composite material is used to withstand the heat. The high forces and high heat dictate that the Shuttle has short, blunt wings. The Shuttle flies at a high angle of attack during re-entry to generate drag to dissipate speed. It executes hypersonic "S-turn" maneuvers to kill off speed during re-entry. The lift of the wings is only important in the final flare maneuver at touchdown.
The Soyuz, Shenzhou, and all of the early Apollo, Gemini, and Mercury spacecraft used a thermal protection system that is different than the Space Shuttle. Each of these spacecraft use an ablative, or "burning", heat shield. The heat shield is made of special ceramic materials and is designed to slowly burn away as it encounters the high temperature plasma flow aft of the bow shock wave. The change of phase from solid to liquid to gas and the convection of the flow away from the spacecraft help to protect the astronauts from the heat of re-entry.
https://www.youtube.com/watch?v=RChlt5wdqBs
https://www.youtube.com/watch?v=98K_FbuicLw
Caco