Uzytkownik "robert arndt" napisal w wiadomosci
om...
(WaltBJ) wrote in message
. com...
[snip...]

A pulsejet is a form of ramjet except that the combustion is
intermittent rather than continuous. The pulsejet uses spring loaded
shutter valves that open and close for the imtermittent pulse... but
is still a ramjet that has to be launched into the air by some means
other than the engine for it to work.

No way! They have different thermodynamical cycles! A pulsejet uses constant
volume combustion cycle while ramjet uses constant pressure combustion
cycle. Since constant volume combustion cycle is a little bit more effective
(in thermodynamical terms) then exist some rocket motors using this cycle.
Are these rockets ramjets or pulse jets?

A pulsejet motor can be started at ZERO ground speed when you supply
sufficient airstream. Once started pusejet will wor fine when you cut this
additional airstream. You can start ramjet in the same way, but when you
stop auxillary airstream ramjet will cease to work. When in high school I
attended two semesters of aeroengines. I recall one lesson when we started a
pulse jet in the way described by Keith. It took 15 min to ignite the motor
but then it worked fine. What a noise!!!

The Germans had both the As044 and Jumo 226 pulsejets under
development at the end of the war- both were investigated by the
Russians from '45-'47.

Rob

Regards
JasiekS
Warsaw, Poland