SpudFiles

This one I know works. A couple of years ago the Resistance fighters used a reworked generator motor as an automatic fire RPG launcher. They fired 20+ rockets at that hotel the Army had previously shelled during the push to Baghdad. They pegged quite a few coalition people including a Colonel in the USMC.
Alas they missed getting Wolfowitz. It was Wolf-Whizzes first and only combat experience.

I would bet they used the starter motor to spin the crankshaft. They probably had taken the cylinder head off one side of the motor,Probably put a couple of tubes into the tops of the cylinder, with a port cut into the side of each tube. A smaller diameter tube which would be the barrel and receiver would then go into outer tube and rest on the top of the piston, maybe epoxied to it. whole length of the firing mechanism would have been like 5" which would be plenty of barrel because they were firing rockets. All they would have needed by way of blast would be to get the rockets going out the tubes at a reasonably fast clip.

Standard recoilless rifles/rpg launchers like the LAWS don't offer much actual impact, or velocity. The rockets pick up a little bit of speed in flight but at close range a person could dodge them easily. The explosives payload is what packs the real punch.

Firing a rocket from a short barrel would get a good little ol' velocity going. It would start out like around 600-700 fps and accelerate until it runs out of fuel (or hits somebod... ooops i mean someTHING.)

The Army engineers who picked up the device said it looked like a science fair project.

Wolfowitz, once he got the clearance from his adult handlers to come out from under his desk, and changed his pants, said that the use of such improvised munitions was a clear sign that the Resistance was on it's last legs and the war was nearly won. That was two years ago.

Ok......

im confused... anyone else?

cool..............so.............. got any plans you wanna share on how to make that rocket launcher?

did they use homemade rockets, of real RPG's ?

Right.

You need to work on communication.

They used a generator motor, ok. Then you're talking about removing the cylinder heads and sticking rocket barrels in there?


Rockets are not fired from a sealed barrel because that makes it unstable, not because anyone wants to waste all that backblast.

Fire a rocket from a short barrel and the backblast will force it out of the tube before it can get the momentum going in the intended direction.

"fire a rocket from a short barrel and the backblast will make it leave the tube too fast; before it can get going fast"

You've put alot of thought into that, havn't you.

Very uncool to edit a quote to give it a different meaning or to cut out the long words which gave it the real meaning.

The rocket would not be leaving it "too fast" as you edited it but too slowly and in an unstable manner.

Yes, I did think about that before posting it but if you want me to expand on it:

I said the backblast forces the rocket out of the barrel before it can get enough momentum going in the direction the barrel is pointed in.

So the rocket is out of the guiding tube without much force behind it because the backblast forced it out too soon, that means it can in fact be pointing in a different direction when it does finally get enough momentum (speed if you like) to keep it going in a straight line.


My reference is anti-aircraft z-rockets used to defend britain in WW2. The initial ones were fired from tubes with a closed rear end to protect the operators, essentially gun barrels but the trapped backblast made the rockets unstable on firing and eventually they were fired from open ended tubes where they worked a lot better and were much more accurate.

He never says anything about wanting to build it he just posted about it. Pointless post.

lol holy $hit im confused

I suppose they used RPGs because there were and still are a whole poopooload of them in country. Basically the setup would have been an autoloading short mortar.

think in terms of (vusualize here, I don't have my CAD program up and running) 3 or 4 "grease gun" type autoloaders, Sten or M3, real simple actions.

lined up in parallel.

The cylinders would be the receivers, so far so good?
The pistons would act as the bolts.
Instead of using the blowback from the launch to push the bolts back, and a spring behind the bolt to push it forward, loading the next round and closing the action, it would use the camshaft.

Take the cylinder heads off.


use a pipe at the same diameter as the piston, riding the top of the piston up and down the cylinder. Fixed firmly to the top of the piston. With a large hole drilled in the side, to allow the fuel/air from the intake valve.
The exhaust valve is now superfluous. All the exhaust will be vented out the barrel anyway.
Since the spark plug sits in the cylinder head, (now removed) you would have to relocate it to the outer pipe, soon to be discussed, be patient here.
The hole in the bolt, that lets in the fuel air mix, would line up with wherever the spark plug would be on the outer pipe.

Rockets aren't really necessary, you could use straight up inert projectiles like slugs oops i mean potato chunks.

I only mentioned rockets because that's what the Iraqis used. Effectively too.

Ok back to the Plan, man...

On the flat surface where the cylinder head used to sit, mount your main barrel/receiver group.


Visualize here, the bolt/pipe has to come up the first part of the barrel/receiver. That pipe would effectively be the bolt. An extension of the piston.

All the barrel you would need for a rocket would be enough tube to hold the rocket in place long enough to ignite it.

For regular projectiles the tube length would be a matter of preference.

The feed would be whatever you feel the most comfortable with in an autoloader.

Turning the crank on a one cylinder, like a chainsaw or weedeater motor, would draw the piston/bolt back and forth.
A two cylinder in parallel, one bolt would be pulled back while the other would be pushed forward. One loading, one firing.

Three cylinders, four, even like a "slant 6" arrangement like the earliest Mustangs... you could get a good cyclic rate of 450 rounds per minute with a hand crank. And without severely overheating your barrels.


What the Iraqis did, apparently, was make a short mortar with multiple barrels.

They needed it like that in order to deploy it quickly. With the short barrels, they would need RPGs to get the range they needed.

And they did. Like I said, they mucked up quite a lot of coalition quarters, personnel and even some equipment.

Where the speed advantage would come in, as opposed to venting the rocket backblast out the back of the tube, it would INITIALLY have a wholehelluvalotta more speed than a regular recoilless, like the bazooka or LAWS. The LAWS has a lower muzzle velocity than a Daisy plinker pistol.

BUT that's only muzzle velocity, rockets accelerate in flight, as opposed to slugs which decelerate as soon as they are out of the muzzle.

[quote="Hotwired"]Very uncool to edit a quote to give it a different meaning or to cut out the long words which gave it the real meaning.

The rocket would not be leaving it "too fast" as you edited it but too slowly and in an unstable manner.

Yes, I did think about that before posting it but if you want me to expand on it:

I said the backblast forces the rocket out of the barrel before it can get enough momentum going in the direction the barrel is pointed in.

So the rocket is out of the guiding tube without much force behind it because the backblast forced it out too soon, that means it can in fact be pointing in a different direction when it does finally get enough momentum (speed if you like) to keep it going in a straight line.


My reference is anti-aircraft z-rockets used to defend britain in WW2. The initial ones were fired from tubes with a closed rear end to protect the operators, essentially gun barrels but the trapped backblast made the rockets unstable on firing and eventually they were fired from open ended tubes where they worked a lot better and were much more accurate.[/quote

Accuracy, for what the Iraqis purposes were, would be (to make a bad pun) pointless.

They weren't shooting at moving objects 3 or 4 miles up in the sky, they were shooting at a honkin' big building less than a mile away.

It would exit the tube the same way any other projectile would, only it would be accelerating instead of decelerating.

As a REALLY good project, perhaps build the thing using a chainsaw motor. Pick up a scrap one for scrap metal prices, less than a buck. With that you get a fully machined action, with a firing mechanism (spark plug) built right in. For under a dollar US.
Have all the moving parts (basically) already manufactured.

Life is sweet when it is simple.

I got the idea to post this because somebody was trying to work a full-auto action for a shoulder mounted ...ahem... "potato" gun in .30 caliber.

also a chainsaw motor has a cylinder diameter of about 3/4" or approximately 12gauge.

Putting a barrel from a flare gun to it would fit almost perfectly.