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Compression ignition?

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GBG

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Many years ago, I read about a gunsmith in the flintlock era who built an experimental air compression ignition system for MLs. The book said percussion ignition was developed shortly after and the heated air idea was dropped and forgotten.

I can't remember the original source, and after many web searches have never found a single reference to it. Does anyone know about this design or the gunsmith who invented it?
 
Like a diesel engine? The theory is that by super compressing the air fuel mixture it will generate enough heat to ignite the fuel and it does indeed work. It does work with other fuels so why not gun powder. How would the compression be accomplished in a gun barrel?
 
Pump it like an air gun, I guess. :idunno:

Archie said:
Like a diesel engine? The theory is that by super compressing the air fuel mixture it will generate enough heat to ignite the fuel and it does indeed work. It does work with other fuels so why not gun powder. How would the compression be accomplished in a gun barrel?
 
I would think the hole in this theory is that the compression required to build enough heat to ignite black powder would have already blown the ball and charge out the end of the barrel.

That is unless the bullet is being used to deliver the compression. But then how does it then get expelled upon ignition? :hmm:

Enjoy, J.D.
 
Don't know about compressed air as an ignition system, but Lewis and Clark had a compressed air rifle with them. It used compressed air as the propellant.
 
So is the theory not the compression of powder to the ignition point but the compression of air until it's beyond the BP ignition temperature and exposing it to the powder?

Even it is a viable theory, it wouldn't be practical even today. Enjoy, J.D.
 
IIRC, a cylinder contained a piston mounted on some type of heavy spring. The piston was cocked with a lever and when released by the trigger, rammed forward compressing/heating the air and driving it through a vent hole into the powder charge for ignition.

The supersonic crack from diesel ignition of gun oils in modern, high powered, spring piston airguns is what brought back the memory of reading about the gunsmith maybe 20-30 years ago.
 
Dieseling air rifles. I had no idea. Interesting. :hmm:
http://www.umarexusa.com/pages/dieselingairrifles.aspx

I guess there a few questions that will probably take a ballistic engineer to answer.

Will the compressed air...assuming it is at a temperature that can ignite BP...being released into the powder chamber ignite the powder before the pressure moves the powder and bullet down or out of the barrel?

How much pressure do you have to apply to air to increase it's temperature beyond the ignition temperature of BP and can it be done with a small, simple hand cocked piston mounted on a gun?

I don't see this as practical but practicallity doesn't always drive invention and if invented it could be why it never caught on. For some folks collecting patents may be a hobby....no matter how silly the invention.

Enjoy, J.D.
 
Last edited by a moderator:
jdkerstetter said:
For some folks collecting patents may be a hobby....
After searching the web for three years with no luck, at this point I'd just like to prove to myself that I did in fact read that info all those years ago.
 
Have you tried searching U.S. Patent department records? http://patft.uspto.gov/ Worth a shot.

Let us know what you find. I'd look but my frustration with government websites gets taxed everyday at work....and I already have a hobby. :grin:

Good luck and enjoy, J.D.
 
I have a RWS spring piston air rifle and diseling is a problem in them if you have oil in the air chamber. For this reason they require a special oil. :idunno:
 
Fire pistons develope enough compression to ignite char . And certainly will ignite black powder. I know a man who tried a few grains in his home made fire piston. And it blew right back and did a number on his hand. Nothing serious just scary! :idunno:
 
Some of us are old enough to remember the Daisy line of VL (caseless) .22 rifles. They were piston-type air rifles which were loaded with a caseless .22 short type cartridge: the propellant was attached to the base of the bullet and was ignited by the hot compressed air. It achieved a muzzle velocity of ca. 1150FPS, IIRC, and could also be shot with standard waisted pellets. The propellant was a type of smokeless (I have a few samples around, somewhere), and must certainly have required an air temperature higher than the ignition point of BP.
Remember that diesel engines ignite their fuel/air mixture with compression ratios in the 22-1 range, I believe, so igniting BP with air compression seems achievable.
mhb - Mike
 
The article I linked above explained the dieseling in air rifles. The non synthetic oils some were using had much lower ignition temps than BP. So I'd have to throw that out as an example.

The fire piston isn't a viable example either as it is a closed system. Likely were you to drill the closed end out and insert a bullet, even tightly, the compression of the air would blow it out before it reached the temperature to ingnite the powder inside.

Diesel engine? Same thing, atomized diesel/air mixtures self ignite under compression at much lower temperatures than BP and it only works in a closed environment.

I think Mike gets the prize. Good catch! I had forgotten about the old Daisy VL. I can't find anywhere what the propellant was made of to determine it's ignition properties. It was a breech loader. I wonder if the same principles could be applied to a ML with BP. :hmm:

Mike may have just solved the mystery. Great post. Enjoy, J.D.
 
We had a compression ignition at Friendship a couple of year ago. I wrote about in Muzzleblasts the next month. The powder was in the barrel and for safety reasons the powder had to be dumped out. The range was going to be closed for fifteen minutes or so. So the man put a spit patch on his big brass cleaning rod and ran it down the barrel. Fifteen minutes later when the range opened back up the man pulled out the cleaning rod, reversed the patch and ran the rod back down. When the cleaning rod reached the bottom there was a loud POP the heavy brass rod was shot up 12 to 15 feet ( according to the witnesses ) in the air. The only thing we can figure, this smoothbore had a Chambers White Lighting liner in it. This vent liner has a very wide vent cone. We think when he ran down the wet patch and left it there for fifteen minutes this packed this vent with damp powder. In the fifteen minutes this little bit of powder dried in the vent. When he took the patch out and ran it back in the touch hole was sealed and the Diesel effect occurred.
I do not know for sure this is what happened but this did happen with four witnesses. I did not inquire as to how many of the witnesses had to change skivvies!
 
I can imagine that the fire piston could work as a model.

If the chamber were not closed but ended with a small vent to the breech then it could easily reach 425 degrees to initiate the black powder.

I almost want to make one to try it except for the minor problem of having no talent, skill or tools.
 
The question remains, can the hot air under pressure ignite the powder before the air pressure moves the powder and ball down the bore?

In a breech loader the bullet can be sized over bore size to offer the resistance needed to resist this initial burst of air. Can the same be achieved with a bullet loaded from the muzzle? And if so how do you achieve consistancy?

The consistance maybe the reason for failure of such a ignition system. Without consistancy you have no accuracy.

It is documented that Daisy pulled the VL because the ATF deamed it a firearm but Daisy went on to produce .22RF rifles. Many believe the VL would have been pulled by Daisy anyway as accuracy was reported to be poor. Lack of consistancy in ignition or bullet design??? Bullet design can be tweeked, ignition consistancy is a major engineering hurdle.

Great post! Enjoy, J.D.
 
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