Throttle control for pulse jet?
Dwayne Aaron Turley
Is there a way to do this?
Pierre Joubert
>From: dtu...@chopin.udel.edu (Dwayne Aaron Turley)
>Subject: Throttle control for pulse jet?
>Date: 9 May 1995 18:17:45 -0400
>Is there a way to do this?
I thought about this for a long time and before I started spending sweat drops
on trying to design something I came to the conclusion that if there was a way
of doing it , it would have been done by now. The problem is that a pulse
rocket works with reed valves and this is critical to the principle of the
pulse rocket. So it is all or nothing as far as I know.
Pierre
Pierre Joubert
University of Natal
South Africa
E-mail: jou...@cc.und.ac.za
Darin L. Reed
: I thought about this for a long time and before I started spending sweat drops
: on trying to design something I came to the conclusion that if there was a way
: of doing it , it would have been done by now. The problem is that a pulse
: rocket works with reed valves and this is critical to the principle of the
: pulse rocket. So it is all or nothing as far as I know.
: Pierre Joubert
: University of Natal
: South Africa
: E-mail: jou...@cc.und.ac.za
I have considered throttling a pulse jet engine also. One idea that I
came up with was to direct the thrust outward in order to give less
forward thrust. The engine is still at full power but equal thrust to
both sides would give the same result as a decrease in engine speed.
--
Darin Reed
San Antonio, Tx
dr...@crl.com
Dwayne Aaron Turley
>: >Is there a way to do this?
>
>: rocket works with reed valves and this is critical to the principle of the
>: Pierre Joubert
>: University of Natal
>: South Africa
>: E-mail: jou...@cc.und.ac.za
>
>came up with was to direct the thrust outward in order to give less
>forward thrust. The engine is still at full power but equal thrust to
>Darin Reed
>San Antonio, Tx
>dr...@crl.com
>
I understand the basic principle of pulse jet propulsion. I'm in search
of a vibration free, 0, nada, absolutely smooth and yet powerful
propulsion source. Thought about going with an electric ducted fan but
the power to weight ratio is not good enough.
Has anyone considered using an irus(sp) like intake and implimenting
variable reed valves coupled with telescoping exhaust? Just an idea..
Bret Okones
>I thought about this for a long time and before I started spending
sweat drops
>on trying to design something I came to the conclusion that if there
was a way
pulse
>rocket works with reed valves and this is critical to the principle of
the
>
>Pierre
>
>
amount of throttle control? I have no experience with pulse jets in
planes but I have worked with pulse jet mosquito foggers. The
'throttle' range was narrow, but some control was possible. I assume
(possibly incorrectly) that they are based on the same principle.
Gregory W. Page
Gregory W. Page
> amount of throttle control? I have no experience with pulse jets in
> planes but I have worked with pulse jet mosquito foggers. The
> 'throttle' range was narrow, but some control was possible. I assume
> (possibly incorrectly) that they are based on the same principle.
I often thought that instead of trying to throttle the pulsejet, throttle
the thrust. You could do this by using a type of thrust reverser that
vented the gases to the side rather than reversing it. The farther the
reverser intrudes into the jet, the less thrust the vehicle is seeing.
If I had a pulsejet I might try it myself, but maybe someone else could
work one up and see if it worked. I can't think of a reason why not.
Bruce Simpson
> In article <3oopm9$4...@chopin.udel.edu> dtu...@chopin.udel.edu (Dwayne Aaron
> >From: dtu...@chopin.udel.edu (Dwayne Aaron Turley)
> >Subject: Throttle control for pulse jet?
> >Date: 9 May 1995 18:17:45 -0400
>
>
> >Is there a way to do this?
>
>
> I thought about this for a long time and before I started spending sweat drop
> on trying to design something I came to the conclusion that if there was a wa
> of doing it , it would have been done by now. The problem is that a pulse
> rocket works with reed valves and this is critical to the principle of the
> pulse rocket. So it is all or nothing as far as I know.
Perhaps the most pragmatic approach would not be an attempt to reduce
the amount of power generated but reduce the amount of thrust (slightly
different). Maybe some thrust-buckets behind the tailpipe could be used
to reduce (or even reverse) the thrust as required?
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| P.O. Box 24-394 | : br...@faxmail.co.nz |
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Pierre Joubert
>From: smed...@ix.netcom.com (Bret Okones)
>Subject: Re: Throttle control for pulse jet?
>Date: 10 May 1995 23:16:22 GMT
>>
>>I thought about this for a long time and before I started spending
>sweat drops
>>on trying to design something I came to the conclusion that if there
>was a way
>>of doing it , it would have been done by now. The problem is that a
>pulse
>>rocket works with reed valves and this is critical to the principle of
>the
>>pulse rocket. So it is all or nothing as far as I know.
>>
>>Pierre
>>
>>
> Won't increasing/reducing the amount of fuel provide a certain
>amount of throttle control? I have no experience with pulse jets in
>planes but I have worked with pulse jet mosquito foggers. The
>'throttle' range was narrow, but some control was possible. I assume
>(possibly incorrectly) that they are based on the same principle.
There might be but it would not do us any good. The pulse rocket does have a
needle valve for tuning it but as this is a combustion engine you would need
to regulate the air/fuel mixture. It is the same as your car engine in that
you cannot fully regulate engine speed by just increasing the fuel alone.
The method I originally wanted to follow was to regulate fuel,air and
combustion chamber volume but I got onto building Schreckling gas turbine
before I really thought about seriously.
Pierre
Pierre Joubert
>From: dtu...@chopin.udel.edu (Dwayne Aaron Turley)
>In article <3or990$i...@crl8.crl.com>, Darin L. Reed <dr...@crl.com> wrote:
>>: >Is there a way to do this?
>>
>>: of doing it , it would have been done by now. The problem is that a pulse
>>: rocket works with reed valves and this is critical to the principle of the
>>: Pierre Joubert
>>: University of Natal
>>: South Africa
>>: E-mail: jou...@cc.und.ac.za
>>
>>came up with was to direct the thrust outward in order to give less
>>forward thrust. The engine is still at full power but equal thrust to
>
>>Darin Reed
>>San Antonio, Tx
>>dr...@crl.com
>>
>I understand the basic principle of pulse jet propulsion. I'm in search
>of a vibration free, 0, nada, absolutely smooth and yet powerful
>propulsion source. Thought about going with an electric ducted fan but
>the power to weight ratio is not good enough.
>Has anyone considered using an irus(sp) like intake and implimenting
>variable reed valves coupled with telescoping exhaust? Just an idea..
Now we are getting to the point where it would be simpler to build a gas
turbine and have a real jet engine.
Pierre Joubert
>From: "Gregory W. Page" <pa...@airframe.chinalake.navy.mil>
>Subject: Re: Throttle control for pulse jet?
>> Won't increasing/reducing the amount of fuel provide a certain
>> amount of throttle control? I have no experience with pulse jets in
>> planes but I have worked with pulse jet mosquito foggers. The
>> 'throttle' range was narrow, but some control was possible. I assume
>> (possibly incorrectly) that they are based on the same principle.
>I often thought that instead of trying to throttle the pulsejet, throttle
>the thrust. You could do this by using a type of thrust reverser that
>vented the gases to the side rather than reversing it. The farther the
>reverser intrudes into the jet, the less thrust the vehicle is seeing.
>If I had a pulsejet I might try it myself, but maybe someone else could
>work one up and see if it worked. I can't think of a reason why not.
I am told you can only ground run one of these engines for a few seconds
before you start damaging the thing - if that is so it would not allow a
thrust reverser due to the lack of cooling.
Rick Morel
>jou...@cc.und.ac.za (Pierre Joubert) writes:
>> In article <3oopm9$4...@chopin.udel.edu> dtu...@chopin.udel.edu (Dwayne Aaron
>> >From: dtu...@chopin.udel.edu (Dwayne Aaron Turley)
>> >Subject: Throttle control for pulse jet?
>> >Date: 9 May 1995 18:17:45 -0400
>>
>>
>> >Is there a way to do this?
>>
>>
>> I thought about this for a long time and before I started spending sweat drop
>> on trying to design something I came to the conclusion that if there was a wa
>> of doing it , it would have been done by now. The problem is that a pulse
>> rocket works with reed valves and this is critical to the principle of the
>> pulse rocket. So it is all or nothing as far as I know.
>Perhaps the most pragmatic approach would not be an attempt to reduce
>the amount of power generated but reduce the amount of thrust (slightly
>different). Maybe some thrust-buckets behind the tailpipe could be used
>to reduce (or even reverse) the thrust as required?
It's been years (about 30) since I've built any pulsejets, but I
do remember that thottling attempts were hardly worth it. I do recall
that throttling range was either 10% or 20%. I think the latter, but
don't hold me to it, okay?
I do like the idea of thrust-buckets or similar to limit thrust,
but I'm fairly certain this would cause enough "detuning" to stop the
engine. It could be a good research project that might result in a
usable method.
Rick
Thalius
> I have considered throttling a pulse jet engine also. One idea that I
> came up with was to direct the thrust outward in order to give less
> forward thrust. The engine is still at full power but equal thrust to
> both sides would give the same result as a decrease in engine speed.
I don't see why throttle on a pulsejet would be so hard. You
could set up a couple of servo rotated plates on the front, arranged to
limit the intake of air through the reed valves via servo control. I
also remember seeing an episode of 'WINGS' where they talked about
buzz-bombs, and how some of the pulsejets we're actually throttled,
although I believe that mechanism would be to complex(and small) for
model use.
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- Jon Caywood / tha...@eskimo.com / Thalius @ FurToonia & Furrymuck -
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- http://www.eskimo.com/~thalius/ -- If it has wings, I can crash it -
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