Hermeus has stolen another quick march on its way to building a hypersonic aircraft as it begins testing its proprietary precooler on a Pratt & Whitney F100 jet engine that will be installed in the company's Quarterhorse Mk 2 prototype.
Hermeus seems to be quite satisfied with its approach toward building a hypersonic aircraft capable of outrunning the legendary SR-71 Blackbird. Instead of constructing a single hypersonic prototype and testing that, the company is working on a series of prototypes, each designed to test one aspect of the flight problem.
For example, the first Quarterhorse aircraft was the Mk 0, which doesn't fly, but can taxi. That way, the engineers could carry out ground tests while the Mk 1 was being built. The Mk 1 isn't intended to do much besides take off and land, but it means flight tests can start while the Mk 2 is on the way. That one will fly supersonic while the more advanced Mark is being built.
Building the supersonic Mk 2 means building an engine that can manage not only supersonic, but high-supersonic speed. More importantly, it has to be able to help sort out the problems of creating a hypersonic aircraft. Specifically, the engine has to be able to handle air coming through the intake at supersonic speed and it needs to be able to reconfigure itself from supersonic to hypersonic flight.
As part of this, the F100 engine has been fitted with a precooler from tests at Edwards Air Force Base in California for sea-level static tests. For these, air is fed into the engine at supersonic speeds and the precooler cools the air intake to prevent the engine parts from melting and to keep the engine working efficiently at speeds over Mach 2.5.
The tests under a variety of loads will be used to gather data for Hermeus’ Chimera turbine-based combined cycle (TBCC) engine. This will use a conventional turbine to power it up to high Mach speeds and then reconfigure itself into a ramjet for speeds in excess of Mach 5.
However, when the Quarterhorse Mk 2 takes to the air, it won't manage much more than Mach 2.5. Anything faster will require the completed Chimera engine for the Quarterhorse Mk 3.
"Air-breathing engines are critical to Hermeus’ goal of rationalizing hypersonic aircraft," said Hermeus co-founder and chief technologist, Glenn Case. "By making a full-range, air-breathing hypersonic engine, Hermeus is setting the stage for aircraft that are capable of taking off from a regular runway and accelerating up to hypersonic speeds. No rockets or motherships required."
Source: Hermeus
