V-4 Missile Possibilities

On 18 Jan 2004 22:34:52 -0800, (robert arndt) wrote:

3) the V-1 had to reach 250mph off the ramp for the pulsejet to
operate independently,

Sorry, take a look at the V1 launch videos (there are two) on this
page:

http://aardvark.co.nz/pjet/argusv1.shtml

and you'll see that the engine is running while the craft is static,
long before it reaches launch speed.

The Argus V1 engine produced a *STATIC* thrust of around 500lbs and a
maximum thrust of around 900lbs at 350mph or so.

There is probably no engine more misunderstood than the humble
pulsejet.

--
you can contact me via http://aardvark.co.nz/contact/

Bruce Simpson wrote in message . ..
On 18 Jan 2004 22:34:52 -0800, (robert arndt) wrote:

3) the V-1 had to reach 250mph off the ramp for the pulsejet to
operate independently,

Sorry, take a look at the V1 launch videos (there are two) on this
page:

http://aardvark.co.nz/pjet/argusv1.shtml

and you'll see that the engine is running while the craft is static,
long before it reaches launch speed.

The initial engine run was done remotely with the purpose of running up to operational temperature. Had the V-1 been launched cold the As014 engine would not function as the operating temperature inside the tube had not been reached. The V-1 could not propel itself off the ramp either and the cycle could not run independently until the missile hit 250 mph.

Rob

Bruce Simpson wrote in message . ..
On 18 Jan 2004 22:34:52 -0800, (robert arndt) wrote:

3) the V-1 had to reach 250mph off the ramp for the pulsejet to
operate independently,

Sorry, take a look at the V1 launch videos (there are two) on this
page:

http://aardvark.co.nz/pjet/argusv1.shtml

and you'll see that the engine is running while the craft is static,
long before it reaches launch speed.

The Argus V1 engine produced a *STATIC* thrust of around 500lbs and a
maximum thrust of around 900lbs at 350mph or so.

There is probably no engine more misunderstood than the humble
pulsejet.

As a follow-up I've read quite a few books on the V-1 launch sequence.
The photos or camera footage of V-1s running on the ramp do NOT mean
the pulsejet was functional.
The engine is being controlled remotely with compressed air and 75
octane fuel forced into the tube and ignited for exactly 7 seconds to
bring the tube up to operating temperature. This would be getting the
V-1 READY for launch. It took .5 seconds of accelleration at 16-17g to
get the missile up to 250mph and the As014 running independently.
If you look at all the other pulsejet aircraft projects they were all
intended to be:

a) launched from a ramp
b) take-off with aux. rockets/engines
c) be air-dropped/launched

Good examples are the Me-328 and Junkers EF 126 built in the USSR
postwar. The pulsejets could not function independently under 200 mph
just like the larger ramjets could not function below a certain speed.
That's exactly why the Germans considered them a "form" of ramjet with
intermittent combustion vs continous combustion. Hence also, the need
for some parts in the pulsejets vs LITTLE or no parts in the bigger
ramjets. There is a great misconception that all ramjets lack any
parts which is NOT true. From that view they consider a pulsejet
different from a ramjet... but they are both essentially just two
types of stovepipe engines.

Rob

p.s. I can see why most make that distinction but my posts were how
the Germans defined it since they were the ones who used them in
combat.

On 21 Jan 2004 08:53:05 -0800, (robert arndt) wrote:

As a follow-up I've read quite a few books on the V-1 launch sequence.
The photos or camera footage of V-1s running on the ramp do NOT mean
the pulsejet was functional.

Sorry but you're dead wrong.

The engine is being controlled remotely with compressed air and 75
octane fuel forced into the tube and ignited for exactly 7 seconds to
bring the tube up to operating temperature.

The engine was *started* using compressed air and, if you do a little
more research, you'll find that in colder weather they also used
acetylene because the gasoline was to hard to ignite at sub-zero
temperatures.

There's *no way* that the starting-air feeds to the Argus engine could
produce sufficient volume-flow to do anything other than start the
engine. If the Argus wasn't capable of running without forward
air-speed it simply would not run -- regardless of the relatively
small volume of compressed air used to start it.

As you can see in the videos on my website -- the engines were
definitely running in full pulsejet mode while stationary on the
launch ramps.

If, as you suggest, the engines required 250mph to operate, what kept
them going for the 5-seconds it took to go from rest to 250mph?

Just do some simple calculations on the amount of air that such an
engine consumes in 5 seconds and you'll see that, there's no way they
could carry that much compressed air onbard the craft. Indeed, the
air reservoirs could only hold a tiny fraction of that mount.

After WW2, the NACA tested a number of the Argus engines and ran them
statically (with no forced air) and at various simulated
ram-pressures. They determined that the engine produced 500lbs of
static thrust (with no forced air of any kind) and around 900lbs at
350mph.

This would be getting the
V-1 READY for launch. It took .5 seconds of accelleration at 16-17g to
get the missile up to 250mph and the As014 running independently.
If you look at all the other pulsejet aircraft projects they were all
intended to be:

a) launched from a ramp
b) take-off with aux. rockets/engines
c) be air-dropped/launched

This was necessary for the reasons I've outlined in a previous post --
ie: with a full fuel-load, the V1 was too heavy to take off without
either an extremely long runway (requiring extra guidance complexity
and a dolly or undercarriage) or by the use of the methods you
describe above. I had nothing to do with the engine requiring
forced-air to actually run.

Good examples are the Me-328 and Junkers EF 126 built in the USSR
postwar. The pulsejets could not function independently under 200 mph
just like the larger ramjets could not function below a certain speed.

While they may have been optimized for higher-speed operation (like
most of the German pulsejet designs), they could operate and produce
static thrust. The reason most of these were relegated to the role of
parsitic fighters is due to their incredibly limited duration, brought
about by the heavy fuel consumption of the pulsejet engines. By
launching them from larger piston-engined craft, they could be flowin
into the battle theater and then released. Their limited range would
have made it impractical for them to fly any distance on their own.

That's exactly why the Germans considered them a "form" of ramjet with
intermittent combustion vs continous combustion. Hence also, the need
for some parts in the pulsejets vs LITTLE or no parts in the bigger
ramjets. There is a great misconception that all ramjets lack any
parts which is NOT true. From that view they consider a pulsejet
different from a ramjet... but they are both essentially just two
types of stovepipe engines.

Just as a V12 Merlin and a turboprop are two types of propellor
engines -- so they must be the same right?

Sorry, but the physics and operating cycle of the pulsejet and ramjet
are as different as night and day. Indeed, a gas-turbine engine is
closer to a ramjet than a pulsejet is.

--
you can contact me via http://aardvark.co.nz/contact/

"Bruce Simpson" wrote in message
news
On 21 Jan 2004 08:53:05 -0800, (robert arndt) wrote:



After WW2, the NACA tested a number of the Argus engines and ran them
statically (with no forced air) and at various simulated
ram-pressures. They determined that the engine produced 500lbs of
static thrust (with no forced air of any kind) and around 900lbs at
350mph.


Those tests are available at

http://naca.larc.nasa.gov/reports/19...a-wr-e-269.pdf

Keith

Bruce Simpson wrote in message . ..
On 21 Jan 2004 08:53:05 -0800, (robert arndt) wrote:

As a follow-up I've read quite a few books on the V-1 launch sequence.
The photos or camera footage of V-1s running on the ramp do NOT mean
the pulsejet was functional.

Sorry but you're dead wrong.

The engine is being controlled remotely with compressed air and 75
octane fuel forced into the tube and ignited for exactly 7 seconds to
bring the tube up to operating temperature.

The engine was *started* using compressed air and, if you do a little
more research, you'll find that in colder weather they also used
acetylene because the gasoline was to hard to ignite at sub-zero
temperatures.

There's *no way* that the starting-air feeds to the Argus engine could
produce sufficient volume-flow to do anything other than start the
engine. If the Argus wasn't capable of running without forward
air-speed it simply would not run -- regardless of the relatively
small volume of compressed air used to start it.

The pulsejet isn't running off a small volume of compressed air. The
distributor unit left of the ramp is feeding it and controlling the 7
second burn up to operating temperature.

As you can see in the videos on my website -- the engines were
definitely running in full pulsejet mode while stationary on the
launch ramps.

Remote controlled by the distributor unit.

If, as you suggest, the engines required 250mph to operate, what kept
them going for the 5-seconds it took to go from rest to 250mph?

That's a half-second or .5, not 5 seconds! Remember the 16-17g launch?



That's exactly why the Germans considered them a "form" of ramjet with
intermittent combustion vs continous combustion. Hence also, the need
for some parts in the pulsejets vs LITTLE or no parts in the bigger
ramjets. There is a great misconception that all ramjets lack any
parts which is NOT true. From that view they consider a pulsejet
different from a ramjet... but they are both essentially just two
types of stovepipe engines.

Just as a V12 Merlin and a turboprop are two types of propellor
engines -- so they must be the same right?

Sorry, but the physics and operating cycle of the pulsejet and ramjet
are as different as night and day.

We are talking As 014 here, an athodyd motor. One stovepipe vs another
except that to achieve pulse detonation some parts are needed in the
pulsejet. Boils down to simple intermittent combustion vs continous
combustion. Both a ramjet and pulsejet need close to 200 mph minimum
to operate independently. On a test rig you can FORCE feed air and
fuel to a pulsejet and even control ignition. But to use them in war
they had to be ramp-launched using a steam reaction piston or
air-dropped by parent aircraft.

Indeed, a gas-turbine engine is
closer to a ramjet than a pulsejet is.

Not in any way since neither a ramjet nor pulsejet have a compressor
or turbine.

Rob

On 22 Jan 2004 08:46:18 -0800, (robert arndt) wrote:

There's *no way* that the starting-air feeds to the Argus engine could
produce sufficient volume-flow to do anything other than start the
engine. If the Argus wasn't capable of running without forward
air-speed it simply would not run -- regardless of the relatively
small volume of compressed air used to start it.

The pulsejet isn't running off a small volume of compressed air. The
distributor unit left of the ramp is feeding it and controlling the 7
second burn up to operating temperature.

Based on some quick mental calculations the Argus requires something
like 1,500 cubic feet of air per minute when running. I'll leave you
to do the calculations but rest assured that there is *no* connection
to the Argus engine capable of supporting anything like that flow-rate
-- and I have a full set of plans here.

Sorry, but the physics and operating cycle of the pulsejet and ramjet
are as different as night and day.

We are talking As 014 here, an athodyd motor. One stovepipe vs another
except that to achieve pulse detonation some parts are needed in the
pulsejet.

Sorry but there is *no* detonation in a pulsejet engine. Go do some
research on the difference between deflagration and detonation.

Boils down to simple intermittent combustion vs continous
combustion. Both a ramjet and pulsejet need close to 200 mph minimum
to operate independently.

Go back and visit my website -- you'll see several videos of pulsejets
operating statically with absolutely *no* forced air. You'll even see
the video of my large pulsejet engine that starts simply by turning on
the gas and the spark with not a zephyr of forced air anywhere in the
vicinity.

Indeed, a gas-turbine engine is
closer to a ramjet than a pulsejet is.

Not in any way since neither a ramjet nor pulsejet have a compressor
or turbine.

Incorrect -- a gas-turbine is a constant combustion device,like a
ramjet and whereas a turbine has a rotating compressor, the ramjet
achieves an increase in static pressure by using a diffuser (go read
up on Bernoulli's theorum to see how that works.

Note also that both the gast turbine and ramjet perform constant
pressure combustion whereas the pulsejet approximates constant volume
combustion.

There are indeed more similarities between a ramjet and a gas-turbine
than there are between a ramjet and a pulsejet -- but don't take my
word for it -- go do some reading.


--
you can contact me via http://aardvark.co.nz/contact/

Bruce Simpson wrote in message . ..
On 22 Jan 2004 08:46:18 -0800, (robert arndt) wrote:



SNIP

Incorrect -- a gas-turbine is a constant combustion device,like a
ramjet and whereas a turbine has a rotating compressor, the ramjet
achieves an increase in static pressure by using a diffuser (go read
up on Bernoulli's theorum to see how that works.


During the 1920s and 1930s a German engineer called Holzworth deigned
and built for the German railways several "constant volume combustion"
gas turbines.

Also von Ohain while working at Heinkel also inspired the construction
of a 60kg thrust constant volume combustion jet engine that produced
60kg thrust. It was damaged in testing and not pursued because of the
urgency of other war time work.

Holzworths gas turbine consisted of a large water jacketed chamber
that was filled with compressed air via a large hydraulically
opperated poppet valve. The Hydraulic poppet valve was then closed,
the mixture ignited and then a second hydraulicaly opperated poppet
valve was opened to exhaust the mixture over a large water cooled
power turbine.

The whole thing opperated at about 50 cycles a second. A pair of
chambers and tubines coupled to a common shaft was used to provide
smooth power. The advantage being that the device was much less
sensitive to turbine and compressor efficiency, the combustion was at
a higher temperature becuase the intermittant nature allowed cooling.

Holzworths engines worked quite well on gas, liquid fuels. They
worked quite well on powdered coal though the abrasion on the turbines
was fairly high.

At one point it seemed that constant volume combustion would win out
over constant pressure combustion. Several projects were looked at by
the Germans as they seemed superior at both generating thrust and gas.
Some used conventional compresseors and systems of poppet valves and
spark plugs that needed to be elaborately sequenced. (this
comblicated things)

Von Ohain engine relied upon a sort of rotating combustion chamber
consisting of blades which partitioned the chamber into sections.
von Ohains engine does have a name (after the town it was built in)
can't recall right now.

All covered in Anthony Kay's book "German Jet Engine and Gas Turbine
development 1930 to 1945"


A lot of these things are worth looking at again.

On 22 Jan 2004 20:46:44 -0800, (Eunometic)
wrote:

At one point it seemed that constant volume combustion would win out
over constant pressure combustion. Several projects were looked at by
the Germans as they seemed superior at both generating thrust and gas.
Some used conventional compresseors and systems of poppet valves and
spark plugs that needed to be elaborately sequenced. (this
comblicated things)

Work is still being done on the application of pulsed combustion to
gas-turbine engines -- but there are many problems that have not yet
been overcome.

In theory, a pulsed combustor can be more efficient than a
steady-state combustor.

--
you can contact me via http://aardvark.co.nz/contact/

(robert arndt) wrote in message . com...
Bruce Simpson wrote in message . ..
On 21 Jan 2004 08:53:05 -0800, (robert arndt) wrote:


I think you'll find that Paul Schmidt's valveless pulsejets (that were
superior to the valved Argus engies which he nevertheless assisted
Argus in designing) could resonate at zero velocity. I do recall
reading that a V1 engine required 26mph to opperate but I'm all open
on this. I imagine that the expulsion of hot gases out of the rear of
the Argus tube could by its own inertia continue moving and thereby
partialy void the combustion chambers and create sufficient vacuum to
draw in a fresh charge of air over the valves. Similar to the way
'extractor' exhausts work in cars. (I think the term is
Schwungaufladdung in German IC engine terminology)

Some of Schmidt's cruise missiles designes and engines had zero
frontal area for the intake. The intake was simply a 'cigar band'
mesh 2/3rds of the way along the missile. The resonating effect
drawing in air around the circumfrence. Very elegant.

Schmidts designes were more advanced, superior anbd actualy worked at
700kg thrust but I beleive they didn't get into the V1 because Schmidt
wanted to hang onto his patents which helped Argus advance faster into
production.

Bruce Simpson incidently has quite a lot of credibillity on these
matters as he was featured in Junkyard wars making pulsejet powered go
carts and featured in the news for his dersire to build a backyard
cruise missile.