Rotary cannons
Join Date: Feb 2008
Location: East Sussex UK
Age: 66
Posts: 6,995
Likes: 0
Received 1 Like
on
1 Post
Mind you Rotary Cannons could soon be old hat once the Electromagnetic Railgun comes of age ... a projectile traveling >Mach 10 at Sea Level ... the KE Yield producing outstanding destructive power 
Just ignore the compass/HSI when firing
Coff.
Just ignore the compass/HSI when firing
Coff.
I don't own this space under my name. I should have leased it while I still could
Interesting about the drive bands. The 30mm Aden round I have has a copper drive band. The 27mm Mauser a steel one as you say. The 30mm GAU OTOH appears to have two nylon drive bands; the round itself also has rifle scoring on one side.
Join Date: May 2008
Location: Cambridge, UK
Age: 45
Posts: 38
Likes: 0
Received 0 Likes
on
0 Posts
I remember reading something about the development of Typhoon that they evaluated various different options including an equivalent to the M61 Gatling gun used in most USAF aircraft before settling on a pistol-fed gun. One reason they cited was that the initial rate of fire of the latter was very close to the maximum whereas the gatling has the latency and initial inertia of the spin-up period...
Join Date: Apr 2005
Location: Europe
Posts: 414
Likes: 0
Received 0 Likes
on
0 Posts
Thanks gents, always learning!
Found this http://www.google.co.uk/url?sa=t&rct...eL4wafEYszl0wA
not what I originally read but similar conclusions. M61 spin up time of 0.55sec v's BK27 0.05sec seems significant.
Obviously I accept it is theory only and would always bow to the advice of those that have been there!
What are the most likey AtoA gun shots against another figher, do you get behind and stay there or get split second chances?
Found this http://www.google.co.uk/url?sa=t&rct...eL4wafEYszl0wA
not what I originally read but similar conclusions. M61 spin up time of 0.55sec v's BK27 0.05sec seems significant.
Obviously I accept it is theory only and would always bow to the advice of those that have been there!
What are the most likey AtoA gun shots against another figher, do you get behind and stay there or get split second chances?
regarding how does a revolver cannon work, the following may help, see the cutaway and gif
Revolver Cannon Design
Revolver Cannon Design
Gat vs. revolver: Gats are heavier and because of their high rate of fire, need a large ammo store with a high-rate feed system, which makes the whole installation much heavier and bulkier.
The Russian approach in the Su-27 has been to reduce the number of rounds and burst length (because flight control and sensors and HUD make the shot more accurate) and stick to a single-barrel gun - which is not even a revolver cannon:
DEVELOPMENT OF SU
The Russian approach in the Su-27 has been to reduce the number of rounds and burst length (because flight control and sensors and HUD make the shot more accurate) and stick to a single-barrel gun - which is not even a revolver cannon:
DEVELOPMENT OF SU
Join Date: Dec 2006
Location: UK
Posts: 799
Likes: 0
Received 0 Likes
on
0 Posts
Guys,
Perhaps I can contribute to this thread - for a while I was in charge of the 'Aden 25' revolver cannon project for the UK Harrier.
I found working with guns fascinating, particularly as the tools available to air forces to build their requirements for aircraft guns were generally subjective, or primitive, or owned by gun manufacturers, which made them even less reliable. In some cases, quite sophisticated models had been developed for assessing gun system lethality, but some of them were seriously flawed. These factors were at play on both sides of the Atlantic, as were the most influential - dogma and emotion.
It's possible to do a very accurate comparison of aircraft gun systems - essentially you can develop a 'performance index' which measures the probability of a 'kill' against the weight and volume of the gun system. On that measure, revolvers usually win - they are lighter, take less space, and get a lot more shells away on target in the short bursts usually employed in combat.
Gatlings are very reliable and use up less barrels (although modern materials are closing that gap), but the main reason the US use them is that they've invested a lot of time and effort into developing them and are reluctant to change. The F-35's change from a Mauser 27 to the 25mm GAU-12 was justified on grounds of problems with the Mauser's feed system, but the result was a larger loss of fuel and higher weight than anyone would really have wanted.
It's interesting that the Russian article linked out to above shows that they were quite aware that new radars and fire control computers were improving the probability of a hit. (Incidentally, we saw this effect on moving from Sea Harrier FRS1 to FA2 - the Blue Vixen gave excellent range accuracy at gun ranges, which fed into some very accurate results against towed targets). The Russians then appear to have adjusted the gun system to suit - lower rate of fire, but bigger shells, at lower gun weight, to exploit the improved hit probability. The Gsh-301 is, by some margin, the most effective gun out there in terms of 'shells on target per pound of gun system'. Even better than revolvers. Interestingly, it's essentially a 'very big Browning', but very cleverly designed.
Size of round is another major influence - The US have stayed with the 20mm round for some time in air to air cannon, the French and the Russians went for 30mm, while Europe 'split the difference' with the really excellent 27mm round. The 25mm used by the Aden 25 and the Gau-12 is also a good round.
Finally, you need to consider the explosive design of the shell - again, a wide range of choices, with some of the most innovative (and effective) stuff coming from Raufoss of Norway.
Dogma and emotion have, unfortunately, ruled the UK gun scene for some time. The decision to remove the gun from the Typhoon ( and also stop the Aden 25 programme) were made at high level in the RAF on the basis of some really dodgy analysis carried out by DERA at Farnborough, plus ignorance of what a gun system could do.
In the end, any gun system has to reliably deliver rounds on target at the lowest weight, space and cost. It's a balance, driven by requirements. Hope this lot helps a bit.
Best Regards
Engines
Perhaps I can contribute to this thread - for a while I was in charge of the 'Aden 25' revolver cannon project for the UK Harrier.
I found working with guns fascinating, particularly as the tools available to air forces to build their requirements for aircraft guns were generally subjective, or primitive, or owned by gun manufacturers, which made them even less reliable. In some cases, quite sophisticated models had been developed for assessing gun system lethality, but some of them were seriously flawed. These factors were at play on both sides of the Atlantic, as were the most influential - dogma and emotion.
It's possible to do a very accurate comparison of aircraft gun systems - essentially you can develop a 'performance index' which measures the probability of a 'kill' against the weight and volume of the gun system. On that measure, revolvers usually win - they are lighter, take less space, and get a lot more shells away on target in the short bursts usually employed in combat.
Gatlings are very reliable and use up less barrels (although modern materials are closing that gap), but the main reason the US use them is that they've invested a lot of time and effort into developing them and are reluctant to change. The F-35's change from a Mauser 27 to the 25mm GAU-12 was justified on grounds of problems with the Mauser's feed system, but the result was a larger loss of fuel and higher weight than anyone would really have wanted.
It's interesting that the Russian article linked out to above shows that they were quite aware that new radars and fire control computers were improving the probability of a hit. (Incidentally, we saw this effect on moving from Sea Harrier FRS1 to FA2 - the Blue Vixen gave excellent range accuracy at gun ranges, which fed into some very accurate results against towed targets). The Russians then appear to have adjusted the gun system to suit - lower rate of fire, but bigger shells, at lower gun weight, to exploit the improved hit probability. The Gsh-301 is, by some margin, the most effective gun out there in terms of 'shells on target per pound of gun system'. Even better than revolvers. Interestingly, it's essentially a 'very big Browning', but very cleverly designed.
Size of round is another major influence - The US have stayed with the 20mm round for some time in air to air cannon, the French and the Russians went for 30mm, while Europe 'split the difference' with the really excellent 27mm round. The 25mm used by the Aden 25 and the Gau-12 is also a good round.
Finally, you need to consider the explosive design of the shell - again, a wide range of choices, with some of the most innovative (and effective) stuff coming from Raufoss of Norway.
Dogma and emotion have, unfortunately, ruled the UK gun scene for some time. The decision to remove the gun from the Typhoon ( and also stop the Aden 25 programme) were made at high level in the RAF on the basis of some really dodgy analysis carried out by DERA at Farnborough, plus ignorance of what a gun system could do.
In the end, any gun system has to reliably deliver rounds on target at the lowest weight, space and cost. It's a balance, driven by requirements. Hope this lot helps a bit.
Best Regards
Engines
Join Date: Apr 2005
Location: Europe
Posts: 414
Likes: 0
Received 0 Likes
on
0 Posts
Interesting stuff, especially the Russian ideas.
Engines got me thinking, if the concept is moving from strafing to sniping, e.g: First round on target. Then why not use something like the 35mm AHEAD system with a lower rate of fire but a shotgun spread, enhanced lethality and no wayward rounds left to damage/injure no hostiles?
NBS MANTIS Air Defence Protection System - Army Technology
http://www.google.co.uk/url?sa=t&rct...t6BYojQEV_VIOA
If it's a good idea I claim a GEMS, if not forget I mentioned it
With all the stress, weight and maintainance issues involved I wonder how long it will be before lasers end up replacing the cannon. ISTR the US are keen to develop one for the AC-130 as it will have many advantages (apart from sounding cool)
Engines got me thinking, if the concept is moving from strafing to sniping, e.g: First round on target. Then why not use something like the 35mm AHEAD system with a lower rate of fire but a shotgun spread, enhanced lethality and no wayward rounds left to damage/injure no hostiles?
NBS MANTIS Air Defence Protection System - Army Technology
http://www.google.co.uk/url?sa=t&rct...t6BYojQEV_VIOA
If it's a good idea I claim a GEMS, if not forget I mentioned it
With all the stress, weight and maintainance issues involved I wonder how long it will be before lasers end up replacing the cannon. ISTR the US are keen to develop one for the AC-130 as it will have many advantages (apart from sounding cool)
Last edited by Ivan Rogov; 31st Mar 2013 at 17:18.
