On Sat, 17 Jan 2004 11:20:36 -0600, Alan Minyard
wrote:

Well, the V-1 used the same type of pulse jet, and they were routinely
shot down. The pulse jet was a dead end technology.

It *was* a dead-end technology. Certainly the arrival of the
gas-turbine meant that the noisy, ineffecient pulsejet was relegated
to the scrap-heap for many years.

However, Ray Lockwood, while working at the HIller Corp in the 1960's
did quite a bit of R&D on a valveless pulsejet that the company touted
as a highly efficient lift engine for VTOL applications.
Unfortunately the noise and vibration problems persisted and it was
never actually used in practice.

Since then however, pulsejets have been used by various manufacturers
for powering low-cost (often disposable) unmanned vehicles such as
RPVs, UAVs and target drones.

More recently, a relation of the pulsejet (the Pulse Detonation
Engine) has attracted a lot of research funding and its proponents
claim it will be *the* jet engine of the future -- offering very high
efficiencies, supersonic capabilities and high power to weight/volume
ratios.

Unfortunately, although a number of cumbersome prototypes have been
demonstrated and actually do run, the efficiency potential has yet to
be even remotely realized.

In the meantime, I have been working on a type of pulsejet engine that
is almost a half-way house in terms of efficiency and performance.
It's documented at http://aardvark.co.nz/pjet/xjet.shtml

No, it's never going to power a manned aircraft, and its efficiency
only matches that of a pure turbojet (but that's still 3 times better
than a regular pulsejet) -- yet it does have a very specific market in
which it represents an ideal powerplant. At a production cost of less
than 10% the price of the equivalent turbojet, it is ideal for
low-cost, high durabiity subsonic UAVs and RPVs.

So the pulsejet isn't dead -- it's just been relegated to a very
specific set of niches.
--
you can contact me via http://aardvark.co.nz/contact/