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#44084 - 03/09/00 04:13 PM A2A gunnery part1, Q?  

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First off, has the author mixed up inch/feet/yard? He says that the dispersion is 5 ft (ca. 1.5 m) at 1000 ft (304 m). Thats really lousy accuracy! 5 ft (60") at 1000 yd (914 m) or 5" at 1000 ft seems way more realistic although, but maybe the accuracy is really lousy? Accuracy in often measured in moa (minute of arc), one moa is usually approximated with one inch at 100 yards, 2 moa is then 2" @ 100 yd etc. 5' @ 1000' = 60" @ 333 yd would then be about 18 moa. A usual hunting-rifle shoots 1-4 moa, better then 1 moa is considered good, worse than 4 is bad...

Question about the tables of rps and weight of fire: what is the horizontal ruler (is that the word, x-axle)?

Interesting article othervice, will give the link to our trainees (and others that might be interested).

S!


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P/O Mikke EAF331

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#44085 - 03/10/00 06:22 PM Re: A2A gunnery part1, Q?  
Joined: Oct 1999
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Andy Bush Offline
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Joined: Oct 1999
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Mikke

The meaning of the text is correct.

I think you may be comparing apples to oranges in this instance! The 'group' that a rifle fires is not a valid comparison to an aircraft cannon.

Aircraft cannon accuracy is expressed as 'dispersion', and that term is measured in mils and % of hits.

The five feet mentioned in the text is a typical dispersion of approximately 80% of the rounds fired impacting within a 5 foot diameter circle at 1000 feet range. The actual accuracy term would be called a '5 mil dispersion' ( one mil equals one foot at 1000 feet range.)

The dispersion is a result of the movement of the gun line of fire (barrel vibration) as the weapon is fired.

As for the figures...I don't have a clue right now what the 'x- axis' represents!! I can't find the web site that I got that figure from...durn...I hate it when that happens!! I intended the figures to be a general picture of weapon capability. Sorry! I'll keep looking for that reference since I'd like to keep it for future use.

Thanks for the question. You mentioned using the article as a reference for your students. What school is this?

Andy

#44086 - 03/12/00 11:58 AM Re: A2A gunnery part1, Q?  

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Guess your right about the accuracy, the way its fixed to the aircraft and how much everything flexes impacts grouping. Guess the patterning is actually not that bad, as it makes the chance that one hits with at least one bullet a bit bigger.

I just remember an anecdote about the swedish Viggen and its 30mm cannon. It is said that the pilot has to "viggle" the plane using the rudder to make sure that not all the bullets land in the same place when firing. Not sure if its true or just our Swedish propaganda at work. :-)

No problem with the table, I have tried to figure it out out, but haven't succeded yet. Not that it matters for the intended use.

The trainees I talked about is the (virtual) pilots that have applied for membership in EAF (European Air Force). Not a school but a virtual sqn. http://www.europeanaf.org

S!

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P/O Mikke EAF331


Moderated by  Andy Bush, RacerGT 

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