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Project Vulcan: T45 and M61

Started by KJ_Lesnick, April 27, 2015, 03:55:19 AM

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KJ_Lesnick

April 27, 2015, 03:55:19 AM
While the USN quickly began deviating away from the 0.50 caliber machine gun ammo in favor of 20mm cannon, the USAAF/USAF seemed to favor the smaller 0.50 and 0.60 calibur cannon: In 1946, the USAAF funded a project which GE began called "Project Vulcan" which was aimed at producing an electrically driven gatling gun, which was originally focused on 0.60 calibur; then later on designs based on 20mm and 27mm designs, focusing on the 20mm ultimately obviously.

I'm curious as to a couple of things

  • Is there any information on the internet about the T45 cannon (I did do a variety of searches)
  • Why did the USAAF/USAF feel the 0.50 calibur was needed for high speed (jet) targets when the USN didn't?
  • How much faster would the 20mm Vulcan cannon have been put in service if they USAAF/USAF focused on 20mm from the outset
That being said, I'd like to remind everybody in a manner reminiscent of the SNL bit on Julian Assange, that no matter how I die: It was murder (even if there was a suicide note or a video of me peacefully dying in my sleep); should I be framed for a criminal offense or disappear, you know to blame.

pyro-manic

#1
April 27, 2015, 06:30:29 AM
http://ww2.rediscov.com/spring/VFPCGI.exe?IDCFile=/spring/DETAILS.IDC,SPECIFIC=15205,DATABASE=objects

.50 does not give enough weight of fire on a high speed target when you've only got a half-second or so of firing time (eg. head on vs bombers) - the US tried to introduce 20mm during the war, but they managed to produce huge numbers of licensed (and needlessly modified ) cannon of the Hispano design that didn't work...
Some of my models can be found on my Flickr album >>>HERE<<<

NARSES2

#2
April 27, 2015, 06:54:00 AM
Quote from: pyro-manic on April 27, 2015, 06:30:29 AM
- the US tried to introduce 20mm during the war, but they managed to produce huge numbers of licensed (and needlessly modified ) cannon of the Hispano design that didn't work...

I didn't know that Pyro. Interesting. I need to delve a little deeper
Do not condemn the judgement of another because it differs from your own. You may both be wrong.

pyro-manic

#3
April 27, 2015, 07:50:37 AM
Some of my models can be found on my Flickr album >>>HERE<<<

PR19_Kit

#4
April 27, 2015, 08:27:39 AM
Kit's Rule 1 ) Any aircraft can be improved by fitting longer wings, and/or a longer fuselage
Kit's Rule 2) The backstory can always be changed to suit the model

...and I'm not a closeted 'Take That' fan, I'm a REAL fan! :)

Regards
Kit

sandiego89

#5
April 27, 2015, 09:01:10 AM
I liked the part of having 40 Million rounds on hand that essentially didn't have a gun they could be used in....

Wonder how long before that stock got used up?  Sort of like the 16 inch shells/powder kegs from WWII, the 750lb bombs and "daisy cutters" left over from Vietnam- only expended decades later.  IIRC some of the 750 pounders had moss on them when re-distributed over Iraq. 
Dave "Sandiego89"
Chesapeake, Virginia, USA

Mr.Creak

#6
April 27, 2015, 09:53:19 AM
Quote from: NARSES2 on April 27, 2015, 06:54:00 AM
Quote from: pyro-manic on April 27, 2015, 06:30:29 AM- the US tried to introduce 20mm during the war, but they managed to produce huge numbers of licensed (and needlessly modified ) cannon of the Hispano design that didn't work...
I didn't know that Pyro. Interesting. I need to delve a little deeper
Tony Williams' book Flying Guns: World War II (http://www.amazon.co.uk/372/dp/1840372273/ref=sr_1_2?ie=UTF8&qid=1430153417&sr=8-2&keywords=flying+guns) has more info IIRC, and you can always check his website, I think it was discussed there (and if it wasn't they have a seriously knowledgeable crew posting who could add more info: http://www.quarryhs.co.uk/).
What if... I had a brain?

KJ_Lesnick

#7
April 27, 2015, 07:19:16 PM
Quote from: pyro-manic on April 27, 2015, 06:30:29 AMhttp://ww2.rediscov.com/spring/VFPCGI.exe?IDCFile=/spring/DETAILS.IDC,SPECIFIC=15205,DATABASE=objects
Thanks for the document!

Quote.50 does not give enough weight of fire on a high speed target when you've only got a half-second or so of firing time (eg. head on vs bombers)
I know that, but with that said: Why did the USAAF/USAF continue to cling to 0.50 and 0.60 cal?

Quotethe US tried to introduce 20mm during the war, but they managed to produce huge numbers of licensed (and needlessly modified ) cannon of the Hispano design that didn't work...
1. What needless modifications?
2. Was the reluctance for 20mm stem from the gun?
That being said, I'd like to remind everybody in a manner reminiscent of the SNL bit on Julian Assange, that no matter how I die: It was murder (even if there was a suicide note or a video of me peacefully dying in my sleep); should I be framed for a criminal offense or disappear, you know to blame.

Logan Hartke

#8
April 27, 2015, 07:30:23 PM
Quote from: KJ_Lesnick on April 27, 2015, 07:19:16 PMWhy did the USAAF/USAF continue to cling to 0.50 and 0.60 cal?

Quote from: PR19_Kit on April 27, 2015, 08:27:39 AM
'If it ain't broke, don't fix it!'

Cheers,

Logan

pyro-manic

#9
April 27, 2015, 07:34:25 PM Last Edit: April 27, 2015, 07:46:47 PM by pyro-manic
If you go to the wiki page, there are a couple of good docs in the reference list.

I don't know what the alterations were, but they were not necessary as the original gun worked very well! One mentioned was a longer chamber.

The .60 cal was one of the trial calibres - it was not selected for production. I assume (I haven't read up on it)  that it didn't give adequate firepower compared to the 20mm. The USAAF eventually got a working 20mm cannon in the shape of the M24, replaced by the M39 revolver cannon. Before that they stuck with .50s because it was the only working option.

Read these: http://www.quarryhs.co.uk/CannonMGs.htm
http://www.quarryhs.co.uk/US404.htm
Some of my models can be found on my Flickr album >>>HERE<<<

KJ_Lesnick

#10
April 29, 2015, 03:17:16 PM
Quote from: pyro-manic on April 27, 2015, 07:34:25 PMI don't know what the alterations were, but they were not necessary as the original gun worked very well!
If I recall, it's accuracy wasn't as good, but it didn't matter for ranges used.

QuoteOne mentioned was a longer chamber.
That seems like an attempt to fix that

QuoteThe USAAF eventually got a working 20mm cannon in the shape of the M24, replaced by the M39 revolver cannon.
Sounds right

QuoteBefore that they stuck with .50s because it was the only working option.
20mm had more hitting power, if an improved projectile or cannon design were used it would work...
That being said, I'd like to remind everybody in a manner reminiscent of the SNL bit on Julian Assange, that no matter how I die: It was murder (even if there was a suicide note or a video of me peacefully dying in my sleep); should I be framed for a criminal offense or disappear, you know to blame.

pyro-manic

#11
April 29, 2015, 04:29:14 PM
Did you not read what I posted? They tried "improving" the design and broke it!
Some of my models can be found on my Flickr album >>>HERE<<<

jcf

#12
April 29, 2015, 06:07:50 PM
Quote from: pyro-manic on April 29, 2015, 04:29:14 PM
Did you not read what I posted?

Hey it's Kendra, what'd you expect.  ;D  :banghead:

KJ_Lesnick

#13
April 30, 2015, 03:22:19 PM
Quote from: pyro-manic on April 29, 2015, 04:29:14 PMDid you not read what I posted? They tried "improving" the design and broke it!
Well, I read the first link...
That being said, I'd like to remind everybody in a manner reminiscent of the SNL bit on Julian Assange, that no matter how I die: It was murder (even if there was a suicide note or a video of me peacefully dying in my sleep); should I be framed for a criminal offense or disappear, you know to blame.

KJ_Lesnick

#14
April 30, 2015, 03:27:40 PM
Everybody

From what I got off wikipedia, and this is the starting information I came in with

QuoteIn 1946 the Army issued General Electric a contract for "Project Vulcan", a six-barrel weapon capable of firing 7,200 rounds per minute (rpm). Although European designers were moving towards heavier 30 mm weapons for better hitting power, the U.S. initially concentrated on a powerful 0.60-inch (15 mm) cartridge designed for a pre-war anti-tank rifle, expecting that the cartridge's high muzzle velocity would be beneficial for improving hit ratios on high speed targets.

The first GE prototypes of the 0.60-inch (15 mm) caliber T45 were ground-fired in 1949; it achieved 2,500 rpm, which was increased to 4,000 rpm by 1950. By the early 1950s, the USAF decided that high velocity alone might not be sufficient to ensure target destruction and tested 20 mm and 27 mm alternatives based on the 0.60-inch (15 mm) caliber cartridge. These variants of the T45 were known as the T171 and T150 respectively, and were first tested in 1952.
I'm curious if hypothetically based on the mechanical ability at the time, if in 1947 or 1948, the USAAF updated the requirements to a 20mm cannon, how quickly could it have been brought to active service.

As I understand the first M61's were being fired in 1956, and were active in 1958 or 1959...

QuoteEventually, the 20×102 mm cartridge was determined to have the desired balance of projectile and explosive weight and muzzle velocity.
So the 20x102 was designed specific for the gun?


pyro-manic

QuoteDid you not read what I posted? They tried "improving" the design and broke it!
I did...
That being said, I'd like to remind everybody in a manner reminiscent of the SNL bit on Julian Assange, that no matter how I die: It was murder (even if there was a suicide note or a video of me peacefully dying in my sleep); should I be framed for a criminal offense or disappear, you know to blame.
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