PULSEJET
EXOTIC PROPULSION DESIGN
Pulsejets use the forward speed of the engine and the inlet shape
to compress the incoming air, then shutters at the inlet close while
fuel is ignited in the combustion chamber and the pressure of the
expanding gasses force the jet forward. The shutters then open and
the process starts again at a high frequency. This results in the
buzzing drone for which the experimental pulsejet missile is named
the "BuzzBomb". People have pointed out that pulsejets can be cooled
which would solve the heating problem of the ramjets. They could
also, theoretically, generate "donut-on-a-rope" contrails due to
the engine's operational design.
The known advantages of the Pulsejet engine are:
- Theoretically it has a higher fuel efficency than a normal engine
that keeps constant pressure.
- Engines can be produced in many sizes with many different thrust
ouputs ranging from a few pounds to thousands of pounds.
- They have a very high thrust-to-weight ratio, which means a
lighter engine producing more pounds of thrust than it's weight.
- They are mechanically very simple and have very little moving
parts.
- They do not depend on the oxygen in the atmosphere to provide
as an oxidizer, which means it could go in or out of the atmosphere
|
yea daddio i put this in the aurora research project pretty good too i liked it.
|
You only made three errors
1. they do rely on the atmosphere for the oxidizer for the fuel
2. They Cannot go supersonic (hty only work in thw subsonic range
3. Theyr have a negitive stelth Qualities (they are noisey And they run hot white hot) I own two ove the things one was run on a tethered miniture
aircraft. and the other powered a thethered miniture car,
|
also, pulsejets aren't exactly "advanced" or "new" the V-1 buzz bombs used by Nazi Germany were Pulse Jet powered
and as previously stated, it is a true jet, an evolution of the classic turbo-jet design, and as such requires atmospheric oxygen
it's a turbo-jet evolution that went nowhere
|
I once saw a concord jet winged shaped aircraft flying at about 30,000 feet with a "dash-dash-dash" contrail. I imagine it was indicative of pulse
propulsion. Anyone else ever see such a jet that left a broken line contrail?
|
Pulse detonation engines are more interesting, and there is more research going on in these engines. Supersonic operation is absolutely possible as
it's not relying on a flame front but a non-oichiometric detonation that both provides thrust and compresses the incoming air/fuel in the case of a
valveless version.
I think a rotary valved version would be pretty easy.
|
reply to post by OldSquid
One other error: "They have a very high thrust-to-weight ratio." Ain't so! The best are about 5:1 while current turbo-jets can exceed 8:1; fan-jets
can exceed 12:1 in larger sizes.
Dynajetjerry
|
One very big con to the pulse jet design.
It will shake your brains out! - not a bad option for unmanned maybe so long as the vehicle is well bolted together. But not a good idea for manned
at all.
|
Hey
Such engines can be used in manned craft as well, since the operating frequency of those engines is very high and you can also put engines on some
shock absorbers if you like.
Even betterengine is pulse detonation engine, in which the fuel doesn't burn, but it detonates, and that results in higher effiecency. All those
engines do rely on oxygen from atmosphere, but oxygen can also be in the craft for higher atmosphere and space flight. If you take scramjet inlets for
air compression, you can fly as much as 60km high relying only on atmospheric oxygen. Let me explain. Scramjets can fly at defined speed on given
altitude, due to engine intakes. If you take speeds and altitudes of NASA's hyperX in equation and the highest theoretical scramjet speedof M18, the
highest theoretical altitude is 60km.
Pulse detonation engines are promising, but the technology still has to be tried and perfected. They could be used for single stage reusable orbital
vehickes (carrying additional oxygen of course).
Oh, I'm not sure about donuts on a rope contrail. Could such engine really produce them, or is the frequency of exploisons too high to see those
donuts???
greets
|
