Muzzle brake design

[PaulStafford]

As an aging ex-NASA engineer, it strikes me that none of the muzzle brakes that I have seen on the market today appear to have been designed with proper nozzle theory.

Exhaust gases exiting from the muzzle are clearly supersonic and choked. Every brake I've seen so far uses straight-sided holes, which has to be the least-efficient supersonic nozzle possible. At the least, the exit area should be greater than the throat.

Effective supersonic flow nozzle designs use converging-diverging cross-sections which maximize thrust available from the high-enthalpy conditions (pressure, velocity) in the barrel. The pressure rise across the shock could be used effectively to add a lot more thrust (i.e. reduction in recoil and muzzle rise) than current designs.

This is rocket science, admittedly, but for gosh sakes the converging-diverging nozzle was invented in the late 19th century ("de Laval" nozzle). Can't we do better than some hick design with holes drilled and pointed backwards?

 

[mscott]

Re: Muzzle brake design

Some of us on here are kinda simple. How about a pic or drawing of the most effective design that can be built in your opinion?

 

[Sportin Wood]

Re: Muzzle brake design

When you design one up let me know....

 

[M700Love]

Re: Muzzle brake design

My guess would be that people are using them for the reduced recoil and not for lift off.

 

[Glen Seekins]

Re: Muzzle brake design

Ours was designed with a fluid analysis program and has quite a bit of engineering into it. We didn't just drill a few cross holes and call it good

One thing you need to keep in mind is manufacturability and cost.
I have seen more than my fair share of engineered "perfect widgets" that can not be manufactured or can be, but very costly. Often that cost was there to make it 2% better based on calculations and theory only, but not noticeable in actual use.

 

[treebasher]

Re: Muzzle brake design

Paul,

Comments from the peanut gallery aside, I am trying to wrap my head around how you would use a de Laval nozzle in a muzzle break?

 

[PaulStafford]

Re: Muzzle brake design

You could do worse than making the holes narrowest halfway through the wall, expanding to twice that minimum diameter in a smooth bell shape.

To be more precise, you need the temp and pressure in barrel before the brake, among other things.

 

[Pflyinguy]

Re: Muzzle brake design

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: M700Love</div><div class="ubbcode-body">My guess would be that people are using them for the reduced recoil and not for lift off. </div></div>

That's funny right there! I cant help but picture that scene from October Sky

 

[PaulStafford]

Re: Muzzle brake design

Glen

great points about manufacturability, and glad to hear some CFD was involved!

Rifle dynamics (both physical and fluid)are amazing, and I am always learning more about them.

 

[sputnik]

Re: Muzzle brake design

Having spent the last 8 years in the army, I've decidedly forgotten any semblance of a fluid dynamics foundation I might have had in college. With that said, please forgive any noob-like stumbling about for an answer.
Your post, which I stumbled into by sheer luck while checking my PMs, woke my inner nerd and went looking for an answer. I didn't find anything immediately useful, but apparently some research has been done at the Rock Island Arsenal, but a little while ago, like the 1960s... (http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=AD0276154).
If I had to venture a guess as to why it's not done, I would think that the benefit gained from greater supersonic flow efficiency at the nozzle, thus reducing muzzle flip and the like, is negated by lack of operator comfort. I would bet that this greater efficiency would also greatly increase the level of discomfort experienced by the operator or those around him. My .02. What do you think? What would be the directional pattern/effects of the exhaust gases in an optimized converging-diverging nozzle? Also, wouldn't there be secondary effects from shock propagation and expansion waves as a result of underexpansion?
Thanks for the mental calisthenics!

 

[Massoud]

Re: Muzzle brake design

There's already a thread about this topic. It is in one of the other subforums. In fact I mention the de Laval nozzle, but in relation to recoil. The military has done a lot of studies of muzzle brakes, as have the Brits, Germans, French, etc.

Basically, the brakes you see give acceptable efficiency at acceptable overpressure levels. Research the 3G brake design (designed by 3 guys with name starting with a G) for the most efficient one I've ran across.
Justin

 

[Massoud]

Re: Muzzle brake design

Then check out the RAVEN rarefraction wave recoil reduction system, good stuff.

 

[PaulStafford]

Re: Muzzle brake design

awesome, Massoud, Serge. just the sort of stuff I was looking for!

 

[goober]

Re: Muzzle brake design

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Massoud</div><div class="ubbcode-body">There's already a thread about this topic. It is in one of the other subforums. In fact I mention the de Laval nozzle, but in relation to recoil. The military has done a lot of studies of muzzle brakes, as have the Brits, Germans, French, etc.

Basically, the brakes you see give acceptable efficiency at acceptable overpressure levels. Research the 3G brake design (designed by 3 guys with name starting with a G) for the most efficient one I've ran across.
Justin </div></div>can you add a link for the 3g brake as I cant find anything .cheers

 

[CanPopper]

Re: Muzzle brake design

Yeah, can we have a link to the 3G brake and RAVEN?

 

[Gunn-Fighter]

Re: Muzzle brake design

interested also

 

[goober]

Re: Muzzle brake design

Info coming from Massoud- it is is from a DOD paper so is a design drawing I believe

 

[Pete Lincoln]

Re: Muzzle brake design

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Paul Stafford</div><div class="ubbcode-body">As an aging ex-NASA engineer, it strikes me that none of the muzzle brakes that I have seen on the market today appear to have been designed with proper nozzle theory.

Exhaust gases exiting from the muzzle are clearly supersonic and choked. Every brake I've seen so far uses straight-sided holes, which has to be the least-efficient supersonic nozzle possible. At the least, the exit area should be greater than the throat.

Effective supersonic flow nozzle designs use converging-diverging cross-sections which maximize thrust available from the high-enthalpy conditions (pressure, velocity) in the barrel. The pressure rise across the shock could be used effectively to add a lot more thrust (i.e. reduction in recoil and muzzle rise) than current designs.

This is rocket science, admittedly, but for gosh sakes the converging-diverging nozzle was invented in the late 19th century ("de Laval" nozzle). Can't we do better than some hick design with holes drilled and pointed backwards? </div></div>

Paul. nice to see an ex colleague on here, as an ex ESA ( European Space Agency ) Spacecraft Operations Team Leader I beg to differ with your statement however.
take a look at our muzzle brakes. there is a diploma study project carried out at the University of Applied Science - Osnabrück - Germany behind each and every one.
http://www.hs-osnabrueck.de/profile.html
http://www.ecs.hs-osnabrueck.de/stroemung.html

( as a side note, my son Marvin starts his University studies there ( Maschinebau / Technical Engineering) this comming monday )

I agree with some of your statement, many brakes on the market are god awful drill a few holes designs, some are poorly made, and very agricultural, many more are designs based on what the manufacturer thinks should work, and sometimes they do work fairly well, ( the same comments can be made about suppressor design also ) But..some manufacturers have done thier homework, and there are some fitting posts previouse to my own, One can realy go over the top with muzzle brakes, as ive seen, its possible to do it right, but one has to bear in mind that the commercial manufactire of brakes has to be commercialy viable, its no point designing the most efficient brake ever if it cant be economicaly manufactured and thus hence no one would ever buy it.
Ive got one here that has a pressure induced trapdoor that closes as the bullet passes the trap door, now it works, but i can't convince end users to trust the trapdoor not to stock closed of close at the wrong time, there is a mental block in shooters minds when it comes to placing a steel block in the way of the bore, so it looks like that design is destined for the company museum.
Im pretty much in agreement with what Glen said.

all the best Pete

 

[Emouse]

Re: Muzzle brake design

So you didn't just copy the EBI designs that you originally purchased as finished product??

 

[goober]

Re: Muzzle brake design

they do look remarkably similar--but so what.Peters products reak of great quality

 

[Pete Lincoln]

Re: Muzzle brake design

Emouse, you again.. no we didn't,if you look at the original ebi brakes you will see that they are round, we had Ebi making brakes but he couldn't deliver in the quantity on time and couldn't cope with the variation in types that we required although his quality was very good. Hence we needed to look else where. In the process the whole design was re-thought out and vastly improved.
We had many commercialy available brakes tested by the University and some worked well, others where not so great, all reduced recoil to some extent. The current design is the result of the University developement and proved to be the best balance between efficiency and manufacturable.
Another excellent European made brake is the one from PGM. it almost ( but not quite) achieves the same recoil reduction as ours. Ive seen several copies of ours( at least one from the UK by Jäger sporting arms) and another from Russia.
What came first, the chicken or the egg.

We do our best to keep up with demand on our brakes, but have been often sold out occasionaly, hence we have just increased production and are upping shelf stocked levels to make the brakes available faster.

 

[Massoud]

Re: Muzzle brake design

OK gents I have a few minutes so I looked up that paper with the 3G brake design (and others). Here's the info:

Royal Armament Research and Development Establishment
Memorandum 34/70
Gun Blast and Muzzle Brake Symposium
07 March 1968
AD# 513629

Another good one is:
Ballistics Research Labratory
Memorandum Report 2276
(BRL MR 2276)
MUZZLE DEVICES, A STATE-OF-THE-ART SURVEY
VOLUME I: HARDWARE STUDY
Feb 1973
AD#909325
Edward M. Schmidt

The RAVEN paper is:
Rarefaction Wave Gun Propulsion (RAVEN) Eric Lee Kathe
No report number

You gents will have to find these on the net, there's not a link, I have them as files.
Thanks,
Justin

 

[seanh]

Re: Muzzle brake design

this debate again...I thought it was put to rest. Wasn't it determined that there wasn't enough specific impulse on small caliber ammunition to take effect of the rocket nozzle design? I seem to recall several years ago that it wasn't until you get to something like a 50 BMG that the converging diverging design would be worth the effort.

 

[Voyagertwelve]

Re: Muzzle brake design

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Paul Stafford</div><div class="ubbcode-body"> Can't we do better than some hick design with holes drilled and pointed backwards? </div></div>

I've been using some of these "Hicks" designs pretty extensivly through the years and some work better than others, I can tell you for sure that the JP muzzle brake (beer can turned sideways) pulls a full auto AR down and forward when you fire it, Uglier than sin admitedly but hard to argue with that efficiency. shame that they aren't legal in IPSC Limited class anymore.

 

[ChielScape]

Re: Muzzle brake design

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Pete Lincoln</div><div class="ubbcode-body">
Ive got one here that has a pressure induced trapdoor that closes as the bullet passes the trap door, now it works, but i can't convince end users to trust the trapdoor not to stock closed of close at the wrong time, there is a mental block in shooters minds when it comes to placing a steel block in the way of the bore, so it looks like that design is destined for the company museum.
</div></div>

If you have pics of that I'm sure they'd be very informative.

 

[jwSubMOA]

Re: Muzzle brake design

Massoud, the second paper you reference I used when designing the brake for my 50BMG. Heavy reading but very useful.

 

[Emouse]

Re: Muzzle brake design

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Pete Lincoln</div><div class="ubbcode-body">Emouse, you again.. no we didn't,if you look at the original ebi brakes you will see that they are round, we had Ebi making brakes but he couldn't deliver in the quantity on time and couldn't cope with the variation in types that we required although his quality was very good. Hence we needed to look else where. In the process the whole design was re-thought out and vastly improved.
We had many commercialy available brakes tested by the University and some worked well, others where not so great, all reduced recoil to some extent. The current design is the result of the University developement and proved to be the best balance between efficiency and manufacturable.
Another excellent European made brake is the one from PGM. it almost ( but not quite) achieves the same recoil reduction as ours. Ive seen several copies of ours( at least one from the UK by Jäger sporting arms) and another from Russia.
What came first, the chicken or the egg.

We do our best to keep up with demand on our brakes, but have been often sold out occasionaly, hence we have just increased production and are upping shelf stocked levels to make the brakes available faster. </div></div>


Hmmm,..strange that? EBI stated they delivered ,..you didn't pay! At least not for some considerable time.