If you believe the supermarket "rag mags", look up. Otherwise, indications are pulse detonation engines may not be suitable for manned vehicles. Reports are the vibrations are horrendous.

Probably never. The Germans experimented with these engines at the end of World War II for military purposes, the best known of these applications was the (in)famous V1 flying bomb, which was of course unmanned. However, they also tried it as an alternative propulsion method for airplanes and to extend the range of troop-carrying gliders. These trials were totally unsuccessful, because of high fuel expenditure ranging to about 1 gallon per mile in the tiny V1, and because the engine generates an extremely noisy shockwave that is enough to damage the structure of a light plane, as the Germans quickly found out

No! They are very loud and not very efficient, and not all that powerful, either. They were basically just a stepping stone to real jets. I think that there might be model planes that use them, though.

In reply to lrhorer: Pulsejets DO have shutters. (Technically they're called reed valves). Some pulsejets are shaped like a U, others aren't. This is more to do with design than function. For a simple explanation of how a pulsejet works (including illustrations), go to www.aardvark.co.nz/pjet/howtheywork.shtml ___________________________________________________________ Depends on what you mean by pulse detonation engines. There are two different jet engines that can be described as pulse detonation engines. The first is the pulse-jet, which is a variation of a ramjet. While ramjets are brilliant for high speed, they cannot produce any thrust at standstill or low speeds, because it is the 'ram' of high speed air that gives them their efficiency. The pulse jet is basically a ramjet with a wall of small shutters at its mouth. The shutters open and close in a cycle that coincides with combustion. The shutters close when detonation occurs, which means the exhaust can only go one way. This pushes the craft forward. The shutters then flip open to allow more air into the combustion chamber, and the cycle begins again. These engines give off a 'buzz' when they fly, hence the term 'buzz-bomb' given to the German V-1 rockets, which were powered by pulse jets. The other type of pulse engine is called a Pulse Detonation Wave Engine, or PDWE. This works (I believe) by creating a supersonic pulse of air across the combustion chamber, which pressurises the air as it is ignited. The resulting thrust is very great, and because of the way the engine operates, it can be used for hypersonic flight (speeds higher than mach 5). I believe that these engines can reach into the mach 10+ range. Their one trademark is their smoke-trail, which comes out as pulses along the exhaust plume - it is described as looking like 'donuts on a rope'. The only practical use for these would be hypersonic aircraft, because like ramjets, PDWEs do not work effectively at low speed. They'd be most suited for one of the concept 'orbital passenger liners'. These aircraft are sleek jets that launch, climb up to the very top of the atmosphere, and skim across it at speeds up to mach 30, then descend and land at the destination airport. http://www.aardvark.co.nz/pjet/pde.shtml - this is a pretty good article on the PDE.

Actually, regardless of what was previously said, it is possible in the future but ramjets are much more likely due to their efficiency and practicality. Pulse jets are actually rather efficient in the context as you can produce a pound of thrust per gallon of fuel per hour, depending upon fuel. You can have a pulse jet engine that can produce around 6 pounds of thrust or more depending on fuel, and with an overall weight of less than 2 pounds. Practical propulsion isnt all that likely, but industrial purposes such as heaters and such are already in sparse use.

Ongoing NASA tests out of Dryden Research Center involve testing of scramjet technology. The test piece is fitted to a pegasus missile. When the missile reaches VMAX the scramjet is ignited. First operational test was failure. 2nd test achieved very high mach numbers.