Compression ignition?

[Claude Mathis]

The question remains, can the hot air under pressure ignite the powder before the air pressure moves the powder and ball down the bore?

And, will the force required to generate such pressure effect your aim?

There may be several good reasons why this method of ignition didn't become well known. :wink:

 

[mhb]

I can think of 2 reasons why compression ignition has not been adopted for BP arms:
1. It takes a good deal of work to compress air to the necessary temperature for ignition of any fuel - work which has always been applied by the shooter himself in spring-piston air guns (and, remember, pre-compressed air, which is also use in air guns, cools upon release and expansion, while quickly compressed air is heated, though it, too, begins to cool immediately it commences to expand again). It is simply too much effort for the purpose. In case of any potential sharpshooting dissidents, I admit that it might be possible to use very high pressure pre-bottled air, such as is used in modern airguns, to do the work of compressing the 'working/ignition' air by acting to drive the piston, but think that, too, would suffer from the same objections as:
2. The necessary mechanism to compress the air adds complexity and weight to the arm - far more than the accepted means of ignition in standard ML arms. Then, unless an effective valving mechanism is also present to prevent the entry of powder gasses and solid residue, the piston and cylinder would fairly quickly become so fouled as to prevent proper function - and would be a real PITA to disassemble and clean every time the arm was used (even more work than a wheellock).
It just isn't practical or, really, necessary, given that flint and percussion ignition work well enough for the purpose.
mhb - Mike

 

[Rifleman1776]

Was anyone able to actually observe results of igniton with that incident? e.g. smoke
Methinks it may simply have been compression that spit the ramrod back out, not ignition.
When I clean my rifles, I can get quite a bit of compression with a doubled wet patch.

 

[Dphar]

From some of the posts I am seeing people need to go out and shoot more.
I am sure that is possible to rapidly compress air and create a temperature that would ignite BP.
Would it be PRACTICAL?
Think about it.
If people would learn to use their traditional arms and learn how to keep their powder dry, their flint sharp etc. They would find that the guns really work well and are reliable even in wet weather IF the shooter is properly prepared for the weather. Its ALL possible using only things that were common to any period that firearm would be found.
The interest in using primitive weapons it in the what it takes to make them work.
I have no interest in playing games with lighter flints and trying the waterproof blackpowder.

Dan

 

[FishDFly]

Folks should get The Muzzle-Loading Cap Lock Rifle by Ned Roberts and read it twice and leave the key board alone, person can learn a lot from the book.

r

 

[mhb]

Darn right. Uncle Alvaro is one of my heroes.
mhb - Mike

 

[Grizzled Roberts]

This was a heavy brass rod. There was a loud pop and I forgot to mention the soot on his hands which were around the rod when the ignition occurred. It was not air pressure he was not loading he was just pushing down a almost dry patch.

 

[Zonie]

For what it's worth, the temperature of the compressed air in a gas turbine at 100 psi pressure is over 800 degrees F.

Keeping that in mind for a minute, if someone had a totally sealed breech for whatever reason and they rapidly rammed a patched ball in one long stroke down the bore of a 32 inch long barrel, when the ball was about 4 1/2 inches from the breech plug the pressure would be about 100 psi.

Black powder's ignition point is somewhere around 460 degrees F but heating it in an oven to that temperature might not cause it to actually ignite but I bet a 800 degree F temperature caused by ramming a patched ball that way might give it second thoughts.

Oh, if the bore of the gun was a .50 caliber it would take a little less than 20 pounds of force (19.63) (plus the drag of the patched ball) to create a 100 psi pressure so for most people it's doable.

Now, if folks are loading their rifles like they should where they are taking several short strokes with the ramrod the air heated by the compression will rapidly dissipate while they are moving their hand up higher on the ramrod.
Also, our muzzleloaders have a vent hole to release the pressure under the patched ball before it comes anywhere close to 100 psi.

Add to this that while grabbing another length of ramrod to shove down the bore, if the pressure under the patched ball was let us say only 40 psi the air pressure would push the ramrod back up with a force of about 8 pounds.

I think the bottom line is it could be very possible to cause black powder to ignite if several common guidelines were ignored and the breech was plugged with something.

 

[Col. Batguano]

So does anyone with a spring-piston air gun want to perform this science experiment? Just load a normal pellet, and fill the base with about 1/2 gr. FFFFg and see if you get any smoke when you fire it. For that matter, it would probably work with a pneumatic gun too.

 

[ohio ramrod]

Considering the cost of my RWS air rifle, and the damage that would be done by the powder I'll pass on the proof. I just accept that if oil will disel in it black powder would go boom! :idunno:

 

[mhb]

It would probably NOT work with a pneumatic air rifle, in which the air supply is pre-compressed in a chamber and released by a valve mechanism when the shot is fired - expanding gasses cool immediately when they begin to expand, and would not likely be at high temperature when that occured.
mhb - Mike

 

[Billnpatti]

I can't remember the exact temperature at which black powder ignites but I do know that most all air gun manufacturers will warn agaist using regular oil in the bore of your rifle because the compressed air can ignite it and cause your barrel to rupture. I know some kids who regularly did this to get a bit of smoke, noise and extra velocity and never ruptured a barrel but I sure don't recommend it. If the compressed air can ignite oil, I would suppose it could be made to ignite black powder.

BTW, as an aside, did you know that Lewis and Clark took an air rifle on their expedition?

 

[jdkerstetter]

BTW, as an aside, did you know that Lewis and Clark took an air rifle on their expedition?

Yes, I did. Read an article not to long ago about a guy who replicated it....can't remember where though.

I posted a link to the dieseling problem and the synthetic oil recommendations in air rifles above. Learn something new everyday.

Enjoy, J.D.

 

[Greenjoytj]

As a kid I used to put a drop or two of lighter fluid into the compression cylinder of my pellet rifle in order to get a good diesel effect, it worked great.
When Diesel first designed his engine it used coal dust as fuel.
Germany had lots of coal but little oil deposits. Later it was adapted to use oil as fuel.
I believe Track of the Wolf sells compression fire starter devices.

 

[Grizzled Roberts]

I forgot to mention the firearm was a 28 gauge flintlock smoothbore.

 

[robtattoo]

When Diesel first designed his engine it used coal dust as fuel.
Germany had lots of coal but little oil deposits. Later it was adapted to use oil as fuel.

And I just learned something new! Every day's a schoolday :bow:

 

[Pigman]

This thread has me wondering - Could some of the acedental discharges that have occourd over the years are the product of compression ignition?

Just wondering?

Foster From Flint

 

[JLDee55]

I can think of a few people out there who are full of enough hot air that it might work..lol :shake: