"funnels" on the back of rockets

"funnels" on the back of rockets

Post by Jesse Robeto » Sun, 19 Jul 1998 04:00:00



How come on real rockets they always have funnel like things on the back
of the thruster thingo?
 
 
 

"funnels" on the back of rockets

Post by Bill Westfiel » Sun, 19 Jul 1998 04:00:00


    >How come on real rockets they always have funnel like things on the back
    >of the thruster thingo?

    You mean the divergent section of the motor nozzles?  Those are to
    direct the exploding gasses away from the bottom of the vehicle,
    preventing disaster.

And also maximizing thrust.  "real" rockets need a much larger nozzle than
model rocket motors because they will operate in a near vacuum, and the ideal
nozzle exit pressure is "ambient pressure" (0 in vacuum.)

BillW
--
(remove spam food from return address)

 
 
 

"funnels" on the back of rockets

Post by Roy Gre » Sun, 19 Jul 1998 04:00:00


Quote:

>How come on real rockets they always have funnel like things on the back
>of the thruster thingo?

The "funnels" are called nozzles.  Model rockets have them too, but
you only see the inside part.   The nozzle allows the gasses rushing
from the motor to expand and get out of the rocket efficiently.
(that's a way-too-simple explanation that doesn't really get into all
the physics that are going on, but it's a start)
 
 
 

"funnels" on the back of rockets

Post by Wolfram v.Kipars » Mon, 20 Jul 1998 04:00:00



Quote:

> How come on real rockets they always have funnel like things on the back
> of the thruster thingo?

Do you mean, nozzles?

--
Wolfram von Kiparski
NAR 28643

Get the rec.models.rockets FAQ at: http://www.ninfinger.org/~sven/rockets/rmrfaq.toc.html

 
 
 

"funnels" on the back of rockets

Post by Rwhite90 » Mon, 20 Jul 1998 04:00:00


Quote:
>How come on real rockets they always have funnel like things on the back
>of the thruster thingo?

You mean the divergent section of the motor nozzles?  Those are to direct the
exploding gasses away from the bottom of the vehicle, preventing disaster.
Robb W
 
 
 

"funnels" on the back of rockets

Post by Wolfram v.Kipars » Mon, 20 Jul 1998 04:00:00



Quote:

> And also maximizing thrust.  "real" rockets need a much larger nozzle than
> model rocket motors because they will operate in a near vacuum, and the ideal
> nozzle exit pressure is "ambient pressure" (0 in vacuum.)

...and there are many "real" rockets (sounding rockets and military missiles)
that do not have projecting nozzles - they do have nozzles but they are either
covered by a fairing, or are inside the motor casing just like many of our
model rocket motors.

--
Wolfram von Kiparski
NAR 28643

Get the rec.models.rockets FAQ at: http://www.ninfinger.org/~sven/rockets/rmrfaq.toc.html

 
 
 

"funnels" on the back of rockets

Post by James L. Bal » Mon, 20 Jul 1998 04:00:00


Quote:


> >How come on real rockets they always have funnel like things on the back
> >of the thruster thingo?

> The "funnels" are called nozzles.  Model rockets have them too, but
> you only see the inside part.   The nozzle allows the gasses rushing
> from the motor to expand and get out of the rocket efficiently.
> (that's a way-too-simple explanation that doesn't really get into all
> the physics that are going on, but it's a start)

  Really?  Is that what they are for?..............and all this time I
thought it was so they could pour the rocket fuel in without spilling
any........

(I'm sorry, I just had to say it before I burst...... :-)  I'll accept my
punishment now).

 
 
 

"funnels" on the back of rockets

Post by Vamidpo » Mon, 20 Jul 1998 04:00:00


Quote:
><HTML><PRE>Subject: Re: "funnels" on the back of rockets

>Date: Sun, Jul 19, 1998 12:40 EDT



>> >How come on real rockets they always have funnel like things on the back
>> >of the thruster thingo?

>> The "funnels" are called nozzles.  Model rockets have them too, but
>> you only see the inside part.   The nozzle allows the gasses rushing
>> from the motor to expand and get out of the rocket efficiently.
>> (that's a way-too-simple explanation that doesn't really get into all
>> the physics that are going on, but it's a start)

>  Really?  Is that what they are for?..............and all this time I
>thought it was so they could pour the rocket fuel in without spilling
>any........

>(I'm sorry, I just had to say it before I burst...... :-)  I'll accept my
>punishment now).

></PRE></HTML>

Bad Jim.  Bad, bad Jim.  (Smack on nose with newspaper)<g>

CB

 
 
 

"funnels" on the back of rockets

Post by The Silent Observe » Mon, 20 Jul 1998 04:00:00


Quote:

> >Subject: Re: "funnels" on the back of rockets

> >Date: Sun, Jul 19, 1998 12:40 EDT



> >> >How come on real rockets they always have funnel like things on the back
> >> >of the thruster thingo?

> >> The "funnels" are called nozzles.  Model rockets have them too, but
> >> you only see the inside part.   The nozzle allows the gasses rushing
> >> from the motor to expand and get out of the rocket efficiently.
> >> (that's a way-too-simple explanation that doesn't really get into all
> >> the physics that are going on, but it's a start)

> >  Really?  Is that what they are for?..............and all this time I
> >thought it was so they could pour the rocket fuel in without spilling
> >any........

> >(I'm sorry, I just had to say it before I burst...... :-)  I'll accept my
> >punishment now).

> Bad Jim.  Bad, bad Jim.  (Smack on nose with newspaper)<g>

Heh...  B)

Actually, if you find a collector's copy of Rocket Manual for Amateurs,
by Capt. Brinley, you're likely to see one or more illustrations of
loading a zinc/sulfur rocket (at the launch site) through the nozzle,
using it very much like a funnel...  B)

Fortunately, we don't have to do that any more in order to fly
rockets...

--
 WARNING!!  This area has been designated an official DOPE FREE ZONE!!

      If you're going to be a dope, please do it somewhere else!

Donald Qualls, aka The Silent Observer           NAR # 70141-SR Insured
Rocket Pages             http://members.aol.com/silntobsvr/launches.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

 
 
 

"funnels" on the back of rockets

Post by James L. Bal » Tue, 21 Jul 1998 04:00:00


Quote:


> > >Subject: Re: "funnels" on the back of rockets

> > >Date: Sun, Jul 19, 1998 12:40 EDT



> > >> >How come on real rockets they always have funnel like things on the back
> > >> >of the thruster thingo?

> > >> The "funnels" are called nozzles.  Model rockets have them too, but
> > >> you only see the inside part.   The nozzle allows the gasses rushing
> > >> from the motor to expand and get out of the rocket efficiently.
> > >> (that's a way-too-simple explanation that doesn't really get into all
> > >> the physics that are going on, but it's a start)

> > >  Really?  Is that what they are for?..............and all this time I
> > >thought it was so they could pour the rocket fuel in without spilling
> > >any........

> > >(I'm sorry, I just had to say it before I burst...... :-)  I'll accept my
> > >punishment now).

> > Bad Jim.  Bad, bad Jim.  (Smack on nose with newspaper)<g>

> Heh...  B)

> Actually, if you find a collector's copy of Rocket Manual for Amateurs,
> by Capt. Brinley, you're likely to see one or more illustrations of
> loading a zinc/sulfur rocket (at the launch site) through the nozzle,
> using it very much like a funnel...  B)

> Fortunately, we don't have to do that any more in order to fly
> rockets...

The very first copy of HPR magazine I ever bought was the June 1994 issue.  On
page 31 is a photo of a zinc/sulfur rocket being held upside down with a big
funnel stuck in the nozzle  and somebody pouring "rocket fuel" in with a measuring
cup. :-)

PLEASE: NEWCOMERS, DON'T TRY THIS AT HOME.  Zinc/Sulfur is an extremely sensitive
and dangerous combination!

I'm surprised that nobody has suggested to Jesse Robetoy that he go read the
R.M.R. FAQ (that's "frequently asked questions" Jesse) at
http://dtm-corp.com/~sven/rockets/rmrfaq.toc.html

There's answers to questions in the FAQ that most beginners haven't even thought
to ask yet. :-)

Keep on going, Jesse--you will be providing answers to beginners someday,
yourself. :-)

 
 
 

"funnels" on the back of rockets

Post by PeteAlw » Tue, 21 Jul 1998 04:00:00



Quote:

>How come on real rockets they always have funnel like things on the back
>of the thruster thingo?

Because the hot flamey stuff that comes out of the thruster thingo is
accelleratized to the fastness of that noisy stuff you hear by passing through
an other-way funnel-like thingy before it reaches the funnel-like things you
see, and by going through the funnel-like things it embiggens, which
acceleratizes it to several times faster than that noisy stuff you hear.   The
faster the flamey stuff leaves the thruster thingo, the faster the rocket
travels when it runs out of the gunk it burns.

Peter "a doohickey is a thingamabob that does the job" Alway

 
 
 

"funnels" on the back of rockets

Post by Carl/Lisa Van Cam » Tue, 21 Jul 1998 04:00:00


"RMR Post of the Year!"  You heard it here first!
--Carl Van Camp
Still wiping tears from his eyes...
**********
Quote:


> >How come on real rockets they always have funnel like things on the back
> >of the thruster thingo?

> Because the hot flamey stuff that comes out of the thruster thingo is
> accelleratized to the fastness of that noisy stuff you hear by passing through
> an other-way funnel-like thingy before it reaches the funnel-like things you
> see, and by going through the funnel-like things it embiggens, which
> acceleratizes it to several times faster than that noisy stuff you hear.   The
> faster the flamey stuff leaves the thruster thingo, the faster the rocket
> travels when it runs out of the gunk it burns.

> Peter "a doohickey is a thingamabob that does the job" Alway

 
 
 

"funnels" on the back of rockets

Post by Vamidpo » Tue, 21 Jul 1998 04:00:00


Quote:
><HTML><PRE>Subject: Re: "funnels" on the back of rockets

>Date: Mon, Jul 20, 1998 09:21 EDT


>>How come on real rockets they always have funnel like things on the back
>>of the thruster thingo?

>Because the hot flamey stuff that comes out of the thruster thingo is
>accelleratized to the fastness of that noisy stuff you hear by passing
>through
>an other-way funnel-like thingy before it reaches the funnel-like things you
>see, and by going through the funnel-like things it embiggens, which
>acceleratizes it to several times faster than that noisy stuff you hear.
>The
>faster the flamey stuff leaves the thruster thingo, the faster the rocket
>travels when it runs out of the gunk it burns.

>Peter "a doohickey is a thingamabob that does the job" Alway
></PRE></HTML>

Bad Peter.  Bad, bad Peter.  (Smack) <G>

CB

 
 
 

"funnels" on the back of rockets

Post by Brian Da » Tue, 21 Jul 1998 04:00:00



:>
:>How come on real rockets they always have funnel like things on the back
:>of the thruster thingo?

: Because the hot flamey stuff that comes out of the thruster thingo is
: accelleratized to the fastness of that noisy stuff you hear by passing through
: an other-way funnel-like thingy before it reaches the funnel-like things you
: see, and by going through the funnel-like things it embiggens, which
: acceleratizes it to several times faster than that noisy stuff you hear.   The
: faster the flamey stuff leaves the thruster thingo, the faster the rocket
: travels when it runs out of the gunk it burns.

Could you put that in layman's terms for us, Peter?

--

New Technology, Inc.    web:    http://hiwaay.net/~bday/hara
Huntspatch, AL