Scramjet Inlet Unstart & Hypersonic Heating Lab

Flight Mach number

Mach 7.0

Design range (this inlet)

Mach 6.2 – 9.8

Inlet shock geometry (live)

INLET STARTED

Oblique shock cone converges right on the cowl lip — the inlet is swallowing its design mass flow and feeding supersonic air to the combustor.

Shock angle β

–

Cowl mismatch

–

Thrust state

–

Leading-edge heating (live)

Heat flux – MW/m²

limit

Est. surface temp

–

Material margin

–

How it works

A scramjet has no rotating compressor — the inlet's fixed ramp geometry does the compressing by throwing off an oblique shock cone from the nose. The cone's half-angle β shrinks as Mach rises (a faster stream needs a shallower shock to turn the same amount), so a ramp cut for one Mach number only lines that cone up with the cowl lip across a narrow band of speeds.

β(M) ≈ 5° + 50°·e^(−0.35·(M−3))
cone radius at cowl = (cowl station) · tan β
q(M) ≈ k · M³   (leading-edge heat flux)

Started — the cone lands on the cowl lip, all the intended air is captured and stays supersonic through the combustor.
Unstart — push Mach outside the design band and the cone over- or under-shoots the lip: air spills around the inlet, the shock system collapses upstream, flow chokes down to subsonic, and the engine loses thrust — sometimes violently, in seconds.
Heating — skin-friction/stagnation heating at the sharpest leading edges (nose tip, cowl lip) scales roughly with M³, so pushing for more thrust margin by flying faster runs straight into a materials wall.

Shock cone Cowl lip (started) Cowl lip (unstart) Leading-edge heat

Drag to orbit · scroll to zoom

⚠ Couldn't load the 3D engineThree.js failed to load from the CDN. Check your connection and reload.