"robert arndt" wrote in message
m...
"Kevin Brooks" wrote in message
t...
"robert arndt" wrote in message
om...
Alan Minyard wrote in message
. ..
On 16 Jan 2004 22:22:15 -0800, (robert arndt)
wrote:

(WaltBJ) wrote in message
. com...
Eyeballing those pictures of the As044 and the Pabst ramjet -
IMHO
the
AS044 is a pulse jet (else why the square grilled inlet?) and the
Pabst ramjet is a neat way to convert fuel into smoke and noise.
Its
specific fuel consumption (Kg fuel/newton/hr) must have been very
high
indeed. I believe the ramjet fighter as pictured would have had a
range even less than that of the Me163b. (Little volume for
fuel.)
Doubtless why it never made it off the sketch board.
Walt BJ

Walt,

As for the Fw Ta 283 range question: the plane had enough fuel
(1000+
liters) for 40 minutes of sustained flight. It's climb would have
been
around 17,500 fpm using the Walter rocket motor in the tail plus
the
two ramjets. So you would have less than two minutes of climb to
get
over the bomber stream and then dive down for the attack. I doubt
the
escort fighters would have been able to do anything about it until
the
Ta 283 had to land. More of the aircraft would have probably been
lost
to ground accidents as the Ta 283 had very narrow track landing
gear.

Rob

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.

And it is NOT a form of "ram jet".

Al Minyard

snip

Third, the pulsejet IS a form of ramjet, with intermittent combustion
vs continuous. It cannot operate until it reaches a certain airspeed.
In the Ta 283 this would be accomplished by the Walter rocket in the
tail.

Not true. Pulse jets can begin operation at zero-airspeed. Interesting
photo
of one doing so on this page:

http://www.aardvark.co.nz/pjet/

I'd be reluctant to call a pulse jet a "form of ramjet", being as the
latter
DOES require tremendous forward airspeed and usually relies on no
external
ignition source for the development of thrust other than the compression
of
the airflow.

Brooks

Rob

The Germans defined the ramjet as a propulsive duct or athodyd motor.
The As044 is defined as an intermittent propulsive duct motor
(translation: intermittent ramjet).

- from "Jane's Fighting Aircraft of World War 2"

I guess all four folks who have corrected you are somehow wrong, eh? Who
gives a rat's ass what the Germans "defined the ramjet as"? You said the
pulse jet could not be operated "until it reaches a certain airspeed"...but
the run them on test stands without a continuous pressurized air feed. "A
pulse-jet engine delivers thrust at zero speed and can be started from
rest..." (conceptengine.tripod.com/conceptengine/id17.html ), but the ramjet
does indeed require a high inlet velocity for *both* startup and continuous
operation. The ramjet has no need for moving parts--the old German pulse
jets needed inlet and outlet valves (only later would the valveless pulse
jet be developed, with little practical purpose demonstrated thus far).
Oddly enough, the pulse jet can only operate up to around 600 mph; the
ramjet can generally only operate *above* that speed. The German pulse jets,
IIRC, required an ignition source; ramjets typically do not.

Now what are all those reasons that you decided the pulse jet is a ramjet?

Brooks


Rob