GU-11 or GU-12?

[Kagashi]

...
200 rounds can add 1000 kg? so around 5kg per round I guess. What is the size of the round supposed to be?

Take a google at swedish 57 mm x 438 mm, german 5,0 cm pak 38, and german 5,5 cm gerat 58 ammo. These all weight from 4.5 to 6.3 kg.

So GU-11 cases between 400 and 450mm.

That stuff is HUGE. Are we seriously saying that the GU-11 is supposed to be burst firing naval canon rounds?

Those are the size of round the folks who created the series said it was, so that's what they wanted it to be.

The quantitative differences between Macross era tech and the other eras are more about the over the top nature of Macross than the other eras being especially bad.

That's why I was curious as to if the floated number for 1000kg for a 200round magazine was accurate.
If it IS accurate then yes, they are throwing around some heavy shells (Though possibly DU penetrators will help some)
If the number ISN'T accurate though, then the shells may be smaller/lighter

I've imagined they were "short" rounds, in effect "pistol" rounds. Where as those real life large caliber artillery rounds mentioned above would be "standard rifle rounds", the GU11, fires a shorter round, with the same caliber. Compare the two real life rounds below. The 9mm Parabellum may be 9mm, same as the Mauser round, but it has far less recoil and weight.

http://en.wikipedia.org/wiki/9%C3%9757mm_Mauser
http://en.wikipedia.org/wiki/9%C3%9719mm_Parabellum

[obsessed]

I've imagined they were "short" rounds, in effect "pistol" rounds. Where as those real life large caliber artillery rounds mentioned above would be "standard rifle rounds", the GU11, fires a shorter round, with the same caliber. Compare the two real life rounds below. The 9mm Parabellum may be 9mm, same as the Mauser round, but it has far less recoil and weight.

http://en.wikipedia.org/wiki/9%C3%9757mm_Mauser
http://en.wikipedia.org/wiki/9%C3%9719mm_Parabellum

Oh, I don't know where to begin with how wrong scaling up a pistol cartrige into cannon ammunition is.

Pistol, rifle, cannon, and artillery are ALL diferent.

Have a good read http://www.quarryhs.co.uk/

[FreelancerMar]

Another thing to consider.

The propellant used by the GU11/GU12 are likely to be an order of magnitude more powerful than a modern M1A1 tank shell. This means even MORE recoil than a current shell.

Just something to think about.

[glitterboy2098]

I've imagined they were "short" rounds, in effect "pistol" rounds. Where as those real life large caliber artillery rounds mentioned above would be "standard rifle rounds", the GU11, fires a shorter round, with the same caliber. Compare the two real life rounds below. The 9mm Parabellum may be 9mm, same as the Mauser round, but it has far less recoil and weight.

http://en.wikipedia.org/wiki/9%C3%9757mm_Mauser
http://en.wikipedia.org/wiki/9%C3%9719mm_Parabellum

Oh, I don't know where to begin with how wrong scaling up a pistol cartrige into cannon ammunition is.

Pistol, rifle, cannon, and artillery are ALL diferent.

Have a good read http://www.quarryhs.co.uk/

except from the visuals in the show, that is exactly what they did. image: look at the ejected brass

though the effect/design might be closer to case telescoped rounds.. image
that design would allow the length to be reduced without reducing the overall power of the round.

[Kagashi]

I've imagined they were "short" rounds, in effect "pistol" rounds. Where as those real life large caliber artillery rounds mentioned above would be "standard rifle rounds", the GU11, fires a shorter round, with the same caliber. Compare the two real life rounds below. The 9mm Parabellum may be 9mm, same as the Mauser round, but it has far less recoil and weight.

http://en.wikipedia.org/wiki/9%C3%9757mm_Mauser
http://en.wikipedia.org/wiki/9%C3%9719mm_Parabellum

Oh, I don't know where to begin with how wrong scaling up a pistol cartrige into cannon ammunition is.

Pistol, rifle, cannon, and artillery are ALL diferent.

Have a good read http://www.quarryhs.co.uk/

except from the visuals in the show, that is exactly what they did. image: look at the ejected brass

though the effect/design might be closer to case telescoped rounds.. image
that design would allow the length to be reduced without reducing the overall power of the round.

Thank you GB.

Obsessed...remember, this is a RPG representing fake "science".

And I imagine it would be a scaled DOWN version of existing cannon ammunition, utilized by large 50 ft robots as a "submachine gun". Not scaling up pistol ammo to be 55mm...

The point I was making was simply that two items can be the same caliber, but one can have a lot less powder propelling the round, the round could be shaped differently, and have very different weights (which was the main point of the convo).

So, that real world 40mm Bofors might be pushing out only 120 rounds a minute, but the GU11's shortened 55mm can maintain a much higher rate of fire of 750 rounds a minute because there is a lot less energy pushing the projectile out through the barrel creating a lot less recoil. It's not all that cosmic of a concept...

[obsessed]

Kagashi,
Short rounds have been discussed PAGES ago on this very thread.
Speaking of cosmic concepts, it is not energy that pushes ammo out of its case and out of the barrel. Pressure does. Energy is the force occuring upon impact of the bullet on its target. Its the mechanism of the gun, including number of barrels which affect rate of fire.

FreelancerMar,
"magnitude more powerful" propellant is not plausible. Explosive elements like gasoline, amitol, gunpowder, smokeless powder, etc have specific detonation velocities and pressure. The problem with using higher velocity explosives is they would destroy their breech. Using too powerful propellants turns your cannon barrel into a bomb.
This is the reason one explosive compound is inside the shell, and a lesser explosive in the cartidge/brass/case.

Glitter,
Your link:
http://www.robotechresearch.com/picture ... _large.jpg
If you notice there are 3 cases ejecting from the closest VF-1. Which of these hand drawn, 24 frames per second, anime cartridges are you measuring?

[obsessed]

RECOIL:

For all those commenting about "too much recoil" for the GU-11...
http://commons.m.wikimedia.org/wiki/Fil ... 3.7AA.jpeg

Those 3 rounds in the photo are the 40mm L/60, the 6pdr british (57×441mm) and the 3.7inch AA (94 x 675Rmm). These 3 rounds were all mounted inside the Mosquito fighter-bomber Mk VI, and Mk XVIII.

If an all-wood frame fighter can handle the recoil of a 94mm cannon, than surely a VF will NOT be knocked out of the sky. Since the recoil force didn't snap the wooden structures inside the Mosquito, then its a safe bet VF would survive a burst.

[glitterboy2098]

i'm not measuring them. just pointing out the design (the appearance). they do not show the reducing diameter "neck" usually used with ammunition of that size. (a design which is employed to maximize the propulsive force imparted to the projectile by increasing the pressure)

the visual effect in the show is like that of a giant pistol bullet, or perhaps large shotgun shells.

my suggestion of case telescoped rounds was a hypothetical explanation.. those would result in cartridges of the style we see being ejected, but would retain much of the power of the full sized conventionally cased rounds.

[FreelancerMar]

RECOIL:

For all those commenting about "too much recoil" for the GU-11...
http://commons.m.wikimedia.org/wiki/Fil ... 3.7AA.jpeg

Those 3 rounds in the photo are the 40mm L/60, the 6pdr british (57×441mm) and the 3.7inch AA (94 x 675Rmm). These 3 rounds were all mounted inside the Mosquito fighter-bomber Mk VI, and Mk XVIII.

If an all-wood frame fighter can handle the recoil of a 94mm cannon, than surely a VF will NOT be knocked out of the sky. Since the recoil force didn't snap the wooden structures inside the Mosquito, then its a safe bet VF would survive a burst.

What kind of armor penetration of this wood plane likely to have hmmmmm???? I would imagine not much against modern armor. One also have to take into consideration how effective the round is.

In the novels, the GU11 used Depleted Uranium shells. These are Heavy rounds for AP purposes. Recoil for something like that would be considerable.

[Jefffar]

Not to mention the GU-12is a fully automatic weapon capable of bursts. The big gun Mosquitoes carried weapons that were single shot, sometimes requiring the weapon to be hand loaded for each individual shot.

There is a difference in the forces released by a single shell every few seconds versus several such shells a second.

[obsessed]

Not to mention the GU-12is a fully automatic weapon capable of bursts. The big gun Mosquitoes carried weapons that were single shot, sometimes requiring the weapon to be hand loaded for each individual shot.

There is a difference in the forces released by a single shell every few seconds versus several such shells a second.

Please quote where you're finding Mosquito's 40mm and 57mm were hand loaded and not auto-cannons please and thank you.
Cause what I read is "Molins Class M gun: 6 pounder gun fitted with automatic loader built by the Molins company, a manufacturer of cigarette making machines. It was mounted on the Royal Navy Motor Torpedo Boats and in the RAF Mosquito planes."
See Variants: http://en.m.wikipedia.org/wiki/Ordnance_QF_6-pounder

"The Mk XVIII was armed with a Molins "6-pounder Class M" cannon: this was a modified QF 6-pounder (57 mm) anti-tank gun fitted with an auto-loader to allow both semi- or fully automatic fire.[nb 14] 25 rounds were carried"
See Variants: http://en.m.wikipedia.org/wiki/De_Havilland_Mosquito

There is no data on auto-loader for the 3.7inch gun, however the AA gun did have an auto-loader during WW2. There are no penetration details for the 32pdr 3.7in gun.

So Jeffar, are you saying the GU-11 and 12 have TOO much recoil for the VF to handle? Please, endulge me with your wisdom.

[Jefffar]

I may have been thinking of the 75mm added to some American aircraft. The Molins had an autoloader, which, according to one of the pages you quoted gave it a rate of fire of 55 rounds per minute. The GU-11 fires a comperable round with a rate of fire of 700 rounds per minute according to the Robotech Research page. The 100mm GU-12 fires 10 round bursts in a single attack . (3 seconds or less) this places its rate of fire at at least 200 rounds per minute.

The 32 pounder is closer to the 100mm in projectile size. In a ground anti-aircraft mount, the type reached up to 20 rounds per minute. There is no word that an autoloader was ever attached to the variant added to the Mosquito for trials.

The rate of fire of the GU-11 and GU-12 magnify the recoil issue considerably. From a realism based framework, they don't seem very feasible for use in the air.

[FreelancerMar]

For the record I do not have a problem with the GU11 which is basically just a upgraded modified GAU-8 avenger used by the A10 Thunderbolt. The Recoil of this weapon is well documented. It is the GU12 that I cannot see as a useable VF weapon in the Air.

[obsessed]

For the record I do not have a problem with the GU11 which is basically just a upgraded modified GAU-8 avenger used by the A10 Thunderbolt. The Recoil of this weapon is well documented. It is the GU12 that I cannot see as a useable VF weapon in the Air.

Since this is well documented, please share some references and sources.

[FreelancerMar]

Watch any video of the a10 thunderbolt on the internet in action. This weapon is well documented. It"s the closesed Real Life weapon to the GU11 available. The GU11 more than likely has much more Recoil than the GAU-8 avenger used by the A10 Thunderbolt.

[glitterboy2098]

http://en.wikipedia.org/wiki/GAU-8_Avenger#Recoil

The average recoil force of the GAU-8/A is 10,000 pounds-force (45 kN),[3][16] which is slightly more than the output of one of the A-10's two TF34 engines (9,065 lbf / 40.3 kN each).[17] While this recoil force is significant, in practice a cannon fire burst only slows the aircraft a few miles per hour in level flight.[15]

https://what-if.xkcd.com/21/

The GAU-8 Avenger fires up to sixty one-pound bullets a second. It produces almost five tons of recoil force, which is crazy considering that it’s mounted in a type of plane (the A-10 “Warthog”) whose two engines produce only four tons of thrust each. If you put two of them in one aircraft, and fired both guns forward while opening up the throttle, the guns would win and you’d accelerate backward.

To put it another way: If I mounted a GAU-8 on my car, put the car in neutral, and started firing backward from a standstill, I would be breaking the interstate speed limit in less than three seconds.

the Russians built one that would work even better. The Gryazev-Shipunov GSh-6-30 weighs half as much as the GAU-8 and has an even higher fire rate. Its thrust-to-weight ratio approaches 40, which means if you pointed one at the ground and fired, not only would it take off in a rapidly expanding spray of deadly metal fragments, but you would experience 40 gees of acceleration.

This is way too much. In fact, even when it was firmly mounted in an aircraft, the acceleration was a problem:

The recoil … still had a tendency to inflict damage on the aircraft. The rate of fire was reduced to 4,000 rounds a minute but it didn't help much. Landing lights almost always broke after firing … Firing more than about 30 rounds in a burst was asking for trouble from overheating …

http://en.wikipedia.org/wiki/Gryazev-Shipunov_GSh-6-30

On the Mikoyan MiG-27 the Gsh-6-30 had to be mounted obliquely to absorb recoil. The gun was noted for its high (often uncomfortable) vibration and extreme noise. The airframe vibration led to fatigue cracks in fuel tanks, numerous radio and avionics failures, the necessity of using runways with floodlights for night flights (as the landing lights would often be destroyed), tearing or jamming of the forward landing gear doors (leading to at least three crash landings), cracking of the reflector gunsight, an accidental jettisoning of the cockpit canopy and at least one case of the instrument panel falling off in flight. The weapons also dealt extensive collateral damage, as the sheer numbers of fragments from detonating shells was sufficient to damage aircraft flying within a 200 meter radius from the impact center, including the aircraft firing.

http://en.wikipedia.org/wiki/GAU-13

The GPU-5/A was intended for carriage on a wide range of U.S. tactical aircraft, including the F-15 Eagle and F-16 Fighting Falcon. In the mid-1980s the USAF considered a specialized variant of the F-16 for the close air support (CAS) mission, using the GPU-5, as a substitute to or adjunct for the A-10 Thunderbolt II.

The GPU-5 pod, however, proved unsatisfactory in service. It was briefly tried on some Air National Guard F-16 Fighting Falcons during the 1991 Gulf War, but was removed from service after barely a day of combat use because of its very poor accuracy. Despite the cannon's impressive ballistic characteristics, the pylon mounting was not sufficiently rigid to prevent deflection, and the weapon's heavy recoil exacerbated the problem by causing pylon misalignment.

[Jefffar]

For the record I do not have a problem with the GU11 which is basically just a upgraded modified GAU-8 avenger used by the A10 Thunderbolt. The Recoil of this weapon is well documented. It is the GU12 that I cannot see as a useable VF weapon in the Air.

Since this is well documented, please share some references and sources.

This gives a good summary.

Not the design considerations which had to be put in place to make the A-10 operate in conjunction with the GAU-8. the layout of the gun and landing gear are asymmetrical in order so that the recoil force of the gun does not push the plane off course. Even lined up, a short burst can still cause the plane to decelerate slightly as the recoil force of the gun surpasses half of the total thrust of the engines. Were there a large enough ammunition supply on board the A-10 for more than a few short bursts, it could conceivably force itself out of the air with sustained fire.

Taking this in mind, we look at the GU-11 and GU-12. In this case, the weapon is not mounted rigidly to the aircraft in flight. As shown in the case of the GPU-5/A non-rigidly mounted gunpods vibrate while firing. In the case of the gunpod in question, it actually vibrated enough to throw the pylon it was mounted on out of alignment. The GU-11 and GU-12 would have recoil forces far in excess of what the quad-barrelled 30 mm could generate.

So while forcing the Valkyrie out of the air may be an overstatement, the use of the GU-11 and especially the GU-12 in Fighter mode is likely an unpleasant and potentially damaging experience for the pilot and airframe.

[glitterboy2098]

while i have no doubt that the VF-1's GU hardpoint would be reinforced and designed to handle the GU-11 as much as possible, it would still have issues of stress and increased maintence issues. (the fact the hardpoint is on an arm, which in itself has many extra possible points of failure with the joints and where it locks into place, suggests that with reinforcement it may have some issues anyway)

plus, the Gu-12 would be a very different beast in that regard. i severely doubt that the VF-1 was original designed to use it, so odds are it's even higher recoil would cause even more problems.

consider that the L7 tank cannon, which is the closest real world weapon i can find (at 105mm) with recoil information, has a recoil force of 10 to 60 tons (depending on the sub-variant of the weapon..). for a single shot

firing 10 in the span of a fraction of a second? that's about 100 to 600 tons of recoil force.


that's not a gunpod. that's a heavy metal rocket engine..

a VF-1, according to macross OSM stats, has 23 tons of thrust per engine at max. (so 46 tons of thrust.)

pull that trigger, and not only will you stop moving forward, your going to very rapidly find yourself several hundred feet backwards from where you were. even when moving at mach 5. assuming it doesn't rip off the mecha, or just rip the arms off.

(also, of interesting note. the L7 is classified as a "low recoil" tank weapon.)

[Jefffar]

This is the fastest firing 100mm weapon I could find. It still has a rate of fire less than 1/10th that of which the GU-12 would have.

Edit: A modern, updated, Iranian version of the same gun with at mechanically assisted loading still has the same maximum rate of fire as the older weapon, topping out at 15 rounds per minute.

[obsessed]

while i have no doubt that the VF-1's GU hardpoint would be reinforced and designed to handle the GU-11 as much as possible, it would still have issues of stress and increased maintence issues. (the fact the hardpoint is on an arm, which in itself has many extra possible points of failure with the joints and where it locks into place, suggests that with reinforcement it may have some issues anyway)

plus, the Gu-12 would be a very different beast in that regard. i severely doubt that the VF-1 was original designed to use it, so odds are it's even higher recoil would cause even more problems.

consider that the L7 tank cannon, which is the closest real world weapon i can find (at 105mm) with recoil information, has a recoil force of 10 to 60 tons (depending on the sub-variant of the weapon..). for a single shot

firing 10 in the span of a fraction of a second? that's about 100 to 600 tons of recoil force.


that's not a gunpod. that's a heavy metal rocket engine..

a VF-1, according to macross OSM stats, has 23 tons of thrust per engine at max. (so 46 tons of thrust.)

pull that trigger, and not only will you stop moving forward, your going to very rapidly find yourself several hundred feet backwards from where you were. even when moving at mach 5. assuming it doesn't rip off the mecha, or just rip the arms off.

(also, of interesting note. the L7 is classified as a "low recoil" tank weapon.)

Glitterboy2098,
your narrow view on 1 gun selected to disprove the GU-12 without considering other 100mm cannon. There is no dispute the L7 and the German Rheinmetal 105mm guns have 60 tons of recoil. There is also the Rh 105-30 (30 denoting 30 ton recoil, half that of the primary version).
http://www.army-guide.com/eng/product3595.html

Again, you are only considering 1 out of dozens of 100mm through 105mm guns.

http://www.army-guide.com/eng/product3215.html
The Russian 2A70 uses a long-recoil mechanism. The shells is 100 x 192Rmm firing shells 300 m/s. Your chosen 105mm L7 fires 105 x 607-617Rmm shells, HE 747 m/s and APDS 1475 m/s.

Consierably shorter cases, much less muzzle velocity, much less recoil, and yet still a 100mm gun.

[Jefffar]

while i have no doubt that the VF-1's GU hardpoint would be reinforced and designed to handle the GU-11 as much as possible, it would still have issues of stress and increased maintence issues. (the fact the hardpoint is on an arm, which in itself has many extra possible points of failure with the joints and where it locks into place, suggests that with reinforcement it may have some issues anyway)

plus, the Gu-12 would be a very different beast in that regard. i severely doubt that the VF-1 was original designed to use it, so odds are it's even higher recoil would cause even more problems.

consider that the L7 tank cannon, which is the closest real world weapon i can find (at 105mm) with recoil information, has a recoil force of 10 to 60 tons (depending on the sub-variant of the weapon..). for a single shot

firing 10 in the span of a fraction of a second? that's about 100 to 600 tons of recoil force.


that's not a gunpod. that's a heavy metal rocket engine..

a VF-1, according to macross OSM stats, has 23 tons of thrust per engine at max. (so 46 tons of thrust.)

pull that trigger, and not only will you stop moving forward, your going to very rapidly find yourself several hundred feet backwards from where you were. even when moving at mach 5. assuming it doesn't rip off the mecha, or just rip the arms off.

(also, of interesting note. the L7 is classified as a "low recoil" tank weapon.)

Glitterboy2098,
your narrow view on 1 gun selected to disprove the GU-12 without considering other 100mm cannon. There is no dispute the L7 and the German Rheinmetal 105mm guns have 60 tons of recoil. There is also the Rh 105-30 (30 denoting 30 ton recoil, half that of the primary version).
http://www.army-guide.com/eng/product3595.html

Again, you are only considering 1 out of dozens of 100mm through 105mm guns.

http://www.army-guide.com/eng/product3215.html
The Russian 2A70 uses a long-recoil mechanism. The shells is 100 x 192Rmm firing shells 300 m/s. Your chosen 105mm L7 fires 105 x 607-617Rmm shells, HE 747 m/s and APDS 1475 m/s.

Consierably shorter cases, much less muzzle velocity, much less recoil, and yet still a 100mm gun.

However, a low velocity weapon has some disadvantages that might make it incompatible with a fighter. For starters the slow ammunition speed makes it difficult to engage moving targets. The Russians get around this by using a tube launched guided missile, but there is not such capability listed for the GU-12.

Secondly, the range of a low velocity weapon is much reduced. The BMP-3 gets around this by the capability to fire the gun at a high elevation to allow the shells to arc down onto their target. The mount that a Gu-12 uses in fighter mode does not permit this capability, and manoeuvring the aircraft to make shots in this fashion is likely problematic in a combat situation to say the least.

Third, the slow muzzle velocity precludes the use of APDS as an anti-armour round. The 2A70 instead is mobile fire support for engaging troop clusters, light vehicles and field fortifications with HE-Frag shells. The anti-tank capability is from the tube launched ATGM. As the GU-12 is used on targets to heavily armoured for the GU-11, it needs to have some kind of armour piercing capability which implies a high velocity shell.

Finally, even with the reduced recoil, the 2A70 still has considerable recoil. Starting at about 35 seconds into this video, you can see that the recoil of the weapon still rocks the 20 ton BMP on it's suspension. The Valkyrie only comes in at 15 tons, so it's going to notice that recoil off of single shots. The 2A70 only fires 1 shot at a time, up to 12 rounds per minute. The GU-12 has a rate of fire of at least 200 rounds per minute.

So, looking at all the above, I have to say that the odds are that the GU-12 is a high velocity weapon due to the way it is mounted and it's desired target profile. Even were it not a high velocity weapon, a low velocity weapon would still produce a significant recoil, especially when firing bursts, making using it in the air (and possibly even in a well braced posture on the ground) uncomfortable and potentialy dangerous for the pilot and vehicle.

[obsessed]

However, a low velocity weapon has some disadvantages that might make it incompatible with a fighter. For starters the slow ammunition speed makes it difficult to engage moving targets. The Russians get around this by using a tube launched guided missile, but there is not such capability listed for the GU-12.

Secondly, the range of a low velocity weapon is much reduced. The BMP-3 gets around this by the capability to fire the gun at a high elevation to allow the shells to arc down onto their target. The mount that a Gu-12 uses in fighter mode does not permit this capability, and manoeuvring the aircraft to make shots in this fashion is likely problematic in a combat situation to say the least.

Third, the slow muzzle velocity precludes the use of APDS as an anti-armour round. The 2A70 instead is mobile fire support for engaging troop clusters, light vehicles and field fortifications with HE-Frag shells. The anti-tank capability is from the tube launched ATGM. As the GU-12 is used on targets to heavily armoured for the GU-11, it needs to have some kind of armour piercing capability which implies a high velocity shell.

Finally, even with the reduced recoil, the 2A70 still has considerable recoil. Starting at about 35 seconds into this video, you can see that the recoil of the weapon still rocks the 20 ton BMP on it's suspension. The Valkyrie only comes in at 15 tons, so it's going to notice that recoil off of single shots. The 2A70 only fires 1 shot at a time, up to 12 rounds per minute. The GU-12 has a rate of fire of at least 200 rounds per minute.

So, looking at all the above, I have to say that the odds are that the GU-12 is a high velocity weapon due to the way it is mounted and it's desired target profile. Even were it not a high velocity weapon, a low velocity weapon would still produce a significant recoil, especially when firing bursts, making using it in the air (and possibly even in a well braced posture on the ground) uncomfortable and potentialy dangerous for the pilot and vehicle.

Jeffar,
I am confused which argument you are making.

You are saying that a short 100mm BMP-3 gun cartridge moves the BMP-3, yet you are saying the GU-12 must still fire a higher velocity round? You happen to be contradicting yourself.

You slam the door to your SUV and it shakes. The BMP-3 shakes when its 100mm fires...I don't see it rolling backwards or doing backflips. I'm not seeing your argument.

We are not comparing rates of fire between RL and OSM canon.

One more time, you are saying that a shorter 100mm cartidge is gonna "rock" a BMP but you're proposing a longer, higher velocity cartridge for the GU-12. I just wanna make sure I understand where you're going.

[glitterboy2098]

actually he's not contradicting himself.

he's pointing out:
a lower velocity gun is less than ideal for gunpod use, because it has trouble hitting moving targets, and cannot fire the most effective anti-vehicle rounds.

and

while the lower velocity gun would also have lower recoil, 100mm cannons, even low velocity ones, still have very strong recoil. which could still have trouble in bursts.

which logically leads to:
the GU-12, because it uses the APFSDS rounds, is mostly likely a high velocity cannon.

and

even if it is a low velocity cannon, it would still have immense recoil issues.


---------------

my analysis earlier for the L7 was purely because that was the only weapon near the right size with recoil statistics that i could find.

i had forgotten the existance of the BMp-3's 2A70.
it has a few drawbacks as a base. first, it cannot fire APFSDS, which is the best anti-armor round. it is limited to HE and fragmentation ammo (notuseful vs armored vehicles) and HEAT (an explosive anti-armor warheat.. and one that has more trouble defeating modern day armors than APFSDS)
second, at a muzzle velocit of only 250m/s, it is about 1/10th the velocity of a true anti-armor weapon the same size.

and while i cannot find the recoil specs for it (sadly, this is common with russian weapons), even with the lower muzzle velocity, the recoil is going to be high. several tons at least. enough that firing 10 in a burst would still cause a lot of trouble for a VF.. given a VF's low mass.

[Jefffar]

So, the forum ate my post, here's the cliff notes version.

I was making two separate points which are both valid criticisms of the 2A70 as an example.

First, the 2A70, even with it's low velocity, generates significant recoil enough that, when combined with the rate of fire of the GU-12, would still be very disruptive to the Veritech using it, especially in flight. So the 2A70 does not disprove the contention that a 100mm auto-cannon is going to be too strong for practical use.

Secondly, the 2A70's low velocity approach would not work for the GU-12 due to the arcing fire and low armour piercing effects. It would be like using a grenade launcher in place of an automatic cannon just because the bullets are the same size. Differing velocities mean differing capabilities which means different battlefield roles. The GU-12's role as the primary gun on a fighter requires high velocity.

[guardiandashi]

So, the forum ate my post, here's the cliff notes version.

I was making two separate points which are both valid criticisms of the 2A70 as an example.

First, the 2A70, even with it's low velocity, generates significant recoil enough that, when combined with the rate of fire of the GU-12, would still be very disruptive to the Veritech using it, especially in flight. So the 2A70 does not disprove the contention that a 100mm auto-cannon is going to be too strong for practical use.

Secondly, the 2A70's low velocity approach would not work for the GU-12 due to the arcing fire and low armour piercing effects. It would be like using a grenade launcher in place of an automatic cannon just because the bullets are the same size. Differing velocities mean differing capabilities which means different battlefield roles. The GU-12's role as the primary gun on a fighter requires high velocity.

I know its not specified as such, but I wonder if the gu-12 uses some variation of RAP rounds IE the cannon fires the rounds at relatively low velocity, but the projectiles themselves are rather heavy, because as they travel down the barrel (or as soon as they clear) a rocket motor engages and gets them up to higher velocity.

(I realize its not a perfect solution but it might bridge the performance gap, at least part way. )

[Jefffar]

So, the forum ate my post, here's the cliff notes version.

I was making two separate points which are both valid criticisms of the 2A70 as an example.

First, the 2A70, even with it's low velocity, generates significant recoil enough that, when combined with the rate of fire of the GU-12, would still be very disruptive to the Veritech using it, especially in flight. So the 2A70 does not disprove the contention that a 100mm auto-cannon is going to be too strong for practical use.

Secondly, the 2A70's low velocity approach would not work for the GU-12 due to the arcing fire and low armour piercing effects. It would be like using a grenade launcher in place of an automatic cannon just because the bullets are the same size. Differing velocities mean differing capabilities which means different battlefield roles. The GU-12's role as the primary gun on a fighter requires high velocity.

I know its not specified as such, but I wonder if the gu-12 uses some variation of RAP rounds IE the cannon fires the rounds at relatively low velocity, but the projectiles themselves are rather heavy, because as they travel down the barrel (or as soon as they clear) a rocket motor engages and gets them up to higher velocity.

(I realize its not a perfect solution but it might bridge the performance gap, at least part way. )

There are a couple of problems with that.

First you either need to use a heavier round, thus increasing recoil or you reduce the payload of the round, reducing it's effect.

Second, the rocket motor kicking in can shift the trajectory, reducing accuracy.

Third, the round doesn't reach it's maximum velocity until some distance from the weapon, which means the round may have a reduced on target effect at close range, which is the part of the range band you want to have the most effect at, since a failure to destroy the target at that range usually doesn't leave you another chance to engage.

[jaymz]

You know.....I think you guys REALLY WAAAAY over think this stuff.

We are talking about a weapon using alien technological discoveries to be made in regards to the weapon itself, the materials it is made from as well as the ammunition it uses.

All of that being taken into account to me is more than enough to explain why it has so surpassed the closest thing we have via our current technological standards.

[Jefffar]

I agree that alien handwaivium can certainly deal with a lot of this. But my argument is that it's required to have alien handwavium rather than something plausible based on our modern technologies and the laws of physics.

[ShadowLogan]

So, the forum ate my post, here's the cliff notes version.

I was making two separate points which are both valid criticisms of the 2A70 as an example.

First, the 2A70, even with it's low velocity, generates significant recoil enough that, when combined with the rate of fire of the GU-12, would still be very disruptive to the Veritech using it, especially in flight. So the 2A70 does not disprove the contention that a 100mm auto-cannon is going to be too strong for practical use.

Secondly, the 2A70's low velocity approach would not work for the GU-12 due to the arcing fire and low armour piercing effects. It would be like using a grenade launcher in place of an automatic cannon just because the bullets are the same size. Differing velocities mean differing capabilities which means different battlefield roles. The GU-12's role as the primary gun on a fighter requires high velocity.

I know its not specified as such, but I wonder if the gu-12 uses some variation of RAP rounds IE the cannon fires the rounds at relatively low velocity, but the projectiles themselves are rather heavy, because as they travel down the barrel (or as soon as they clear) a rocket motor engages and gets them up to higher velocity.

(I realize its not a perfect solution but it might bridge the performance gap, at least part way. )

There are a couple of problems with that.

First you either need to use a heavier round, thus increasing recoil or you reduce the payload of the round, reducing it's effect.

Second, the rocket motor kicking in can shift the trajectory, reducing accuracy.

Third, the round doesn't reach it's maximum velocity until some distance from the weapon, which means the round may have a reduced on target effect at close range, which is the part of the range band you want to have the most effect at, since a failure to destroy the target at that range usually doesn't leave you another chance to engage.

I was going to suggest what guardiandashi did, but now I have to wonder if we shouldn't think of the GU-11/12 issue as being more like those energy (Laser/Plasma) weapon cartridges in Rifts that Wilk's (New West) and Naruni Enterprises (PW, Mercenaries, N. Wave 2, etc) produce. Recoil issues should be less without loss in power, and it would work with the spent casings being ejected.

[Jefffar]

I was going to suggest what guardiandashi did, but now I have to wonder if we shouldn't think of the GU-11/12 issue as being more like those energy (Laser/Plasma) weapon cartridges in Rifts that Wilk's (New West) and Naruni Enterprises (PW, Mercenaries, N. Wave 2, etc) produce. Recoil issues should be less without loss in power, and it would work with the spent casings being ejected.

That would work, if we weren't continually told they were kinetic energy weapons.

[obsessed]

You know.....I think you guys REALLY WAAAAY over think this stuff.
... .

That's why I'm called OBSESSED

[ShadowLogan]

I was going to suggest what guardiandashi did, but now I have to wonder if we shouldn't think of the GU-11/12 issue as being more like those energy (Laser/Plasma) weapon cartridges in Rifts that Wilk's (New West) and Naruni Enterprises (PW, Mercenaries, N. Wave 2, etc) produce. Recoil issues should be less without loss in power, and it would work with the spent casings being ejected.

That would work, if we weren't continually told they were kinetic energy weapons.

Well Particle Beams are also said to be kinetic energy weapons, so the "shell" need not be Laser or Plasma.

Macross SB (manga)
pg155/159/163 "These massive cannons produce impressive amounts of heat and kinetic energy, and allow the Regult to punch well above its weight" (Regult types Heavy Particle Cannons). A quick glance at other HPCs in Macross SB don't have any mention of this, but they do mention streams of particles, so it would be kinetic energy weapon.

[guardiandashi]

I was going to suggest what guardiandashi did, but now I have to wonder if we shouldn't think of the GU-11/12 issue as being more like those energy (Laser/Plasma) weapon cartridges in Rifts that Wilk's (New West) and Naruni Enterprises (PW, Mercenaries, N. Wave 2, etc) produce. Recoil issues should be less without loss in power, and it would work with the spent casings being ejected.

That would work, if we weren't continually told they were kinetic energy weapons.

Well Particle Beams are also said to be kinetic energy weapons, so the "shell" need not be Laser or Plasma.

Macross SB (manga)
pg155/159/163 "These massive cannons produce impressive amounts of heat and kinetic energy, and allow the Regult to punch well above its weight" (Regult types Heavy Particle Cannons). A quick glance at other HPCs in Macross SB don't have any mention of this, but they do mention streams of particles, so it would be kinetic energy weapon.

particle beams are kind of funky they in some ways act like a beam weapon but they also have a kick, and do damage through a combination of heat, impact and possibly radiation as well.

[obsessed]

RECOIL:

For all those commenting about "too much recoil" for the GU-11...
http://commons.m.wikimedia.org/wiki/Fil ... 3.7AA.jpeg

Those 3 rounds in the photo are the 40mm L/60, the 6pdr british (57×441mm) and the 3.7inch AA (94 x 675Rmm). These 3 rounds were all mounted inside the Mosquito fighter-bomber Mk VI, and Mk XVIII.

If an all-wood frame fighter can handle the recoil of a 94mm cannon, than surely a VF will NOT be knocked out of the sky. Since the recoil force didn't snap the wooden structures inside the Mosquito, then its a safe bet VF would survive a burst.

What kind of armor penetration of this wood plane likely to have hmmmmm???? I would imagine not much against modern armor. One also have to take into consideration how effective the round is.

In the novels, the GU11 used Depleted Uranium shells. These are Heavy rounds for AP purposes. Recoil for something like that would be considerable.

Freelance,
Yes, the 1940s 40mm, 57mm, and 94mm guns on a wooden Mosquito would give ANY ground vehicle a good punch. The UK 6pdr (57mm) had an armor penetration levels ranging from 90-120mm @ 100m, to 30-60mm in the 1km-2km ranges. http://www.wwiiequipment.com/index.php? ... &Itemid=58
You need to consider that many other WW2 planes fielded anti-tank cannon. http://www.quarryhs.co.uk/tankbusters.htm

Although their BEST armor penetration happened 100 to 500m, none of those aircraft cannon were meant to attack ANY tank head on. They are air planes, they attacked from above (and high angles of attack). These guns do NOT have to penetrate, example a T-72 280 mm frontal armor (effectively 500-600mm depending on slope and composite). The thinnest exposed part of ANY tank were roof tops. As little at 5mm and at much as 25mm for 1940s tanks. Even 1950-1970s tanks had turret sides and roof 40mm (see T-62, T-74, and Leopard 1).

Looking at the A-10's GAU-8a: 69mm penetration ay 500m or 38mm at 1000m... this means that even the A-10 has to hit a MBT from above in a dive and swoop up again within 500m avoiding a ground collision. Clearly the improvement in anti-tank missiles and speed of jet aircraft rendered heavy cannon impractical.

And... recoil has NEVER dropped a plane out of the sky.

*drops microphone*

[Jefffar]

Freelance,
Yes, the 1940s 40mm, 57mm, and 94mm guns on a wooden Mosquito would give ANY ground vehicle a good punch. The UK 6pdr (57mm) had an armor penetration levels ranging from 90-120mm @ 100m, to 30-60mm in the 1km-2km ranges. http://www.wwiiequipment.com/index.php? ... &Itemid=58
You need to consider that many other WW2 planes fielded anti-tank cannon. http://www.quarryhs.co.uk/tankbusters.htm

Although their BEST armor penetration happened 100 to 500m, none of those aircraft cannon were meant to attack ANY tank head on. They are air planes, they attacked from above (and high angles of attack). These guns do NOT have to penetrate, example a T-72 280 mm frontal armor (effectively 500-600mm depending on slope and composite). The thinnest exposed part of ANY tank were roof tops. As little at 5mm and at much as 25mm for 1940s tanks. Even 1950-1970s tanks had turret sides and roof 40mm (see T-62, T-74, and Leopard 1).

Looking at the A-10's GAU-8a: 69mm penetration ay 500m or 38mm at 1000m... this means that even the A-10 has to hit a MBT from above in a dive and swoop up again within 500m avoiding a ground collision. Clearly the improvement in anti-tank missiles and speed of jet aircraft rendered heavy cannon impractical.

And... recoil has NEVER dropped a plane out of the sky.

*drops microphone*

And none of those large barrelled world war 2 era weapons had a rate of fire approaching that of the single barrelled GU-12 let alone the three barrelled GU-11. The pounding they took was much less because of that.

Basically, those weapons are sledgehammers but we are discussing jackhammers.

Also, the 94mm was only used in trials and never mounted to an actual combat aircraft, so we don't know how it would have done in battle, however, the 57mm Mossies were primarily used in the anti-shipping role rather than the anti-tank role, perhaps as a result of the difficulty in landing a hit on a tank in the relatively short span of time one had to make an engagement with such a slow firing and short ranged weapon.

Incidentally, the aircraft that did attack tanks with heavy cannons tended to do their attacks at low level rather than diving due to the risk of hitting the ground. Here's footage of Vickers S (a low powered 40mm cannon, with a muzzle velocity about 1000m/s lower than the Bofors 40mm) being used by Hawker Hurricane tank busters only a few feet off the North African desert http://youtu.be/ix5xN8hlGLo?t=3m30s Also notice the low rate of fire, there are only about 3 shots per gun per aircraft per pass.

So far, nothing presented has actually been representative of the type of weapon the 100mm GU-12 would be. It would have to be high enough velocity to penetrate heavy armour if the Veritech Fighter is in battloid mode on the ground as well as if attacking form above. It needs to have a high enough rate of fire (over 200 rpm by game stats) to be effective in air to air combat as well. So far this is the closest weapon I have found to fitting that bill. The complete weapon system weighs 35 tons, is mounted on naval vessels and still has a rate of fire only about a quarter of that needed to represent the GU-12.

[Alrik Vas]

I like reading this discussion /popcorn

but I gotta agree with Jaymz, advanced over/robotech/win.

[obsessed]

So Jeff,
How many of your Ak-100 rounds (1020mm long overall, 147mm rim)) are you fitting into the Gu-12 gun body?

I'm eagerly anticipating your reply...

[Jefffar]

I'm not. I'm saying it's the closest analog in performance yet found.

The fact that the weapon needs to be so large to even have a fraction of the claimed capabilities (high rate of fire with heavy enough ammunition to destroy tanks from the front) of the GU-12 shows how implausible the GU-12 would be.

[eliakon]

So Jeff,
How many of your Ak-100 rounds (1020mm long overall, 147mm rim)) are you fitting into the Gu-12 gun body?

I'm eagerly anticipating your reply...

Ammunition fitting into weapons has never been a strong point of this universe (Mac II I am looking at you!) Why would we assume that this weapon is any different?

[obsessed]

I'm not. I'm saying it's the closest analog in performance yet found.

The fact that the weapon needs to be so large to even have a fraction of the claimed capabilities (high rate of fire with heavy enough ammunition to destroy tanks from the front) of the GU-12 shows how implausible the GU-12 would be.

So jeffy, if you DENY the GU-12 exists in the Robotech unniverse with your speculation, kindly step away from this thread.

1. EDIT: As far as the RPG Books for Robotech are concerned, this GU-12 DOES NOT exist. As far as other sources of Robotech Fandom, that is a different matter. - NMI
   
   
2. EDIT: You are in NO position whatsoever to tell anyone, much less a moderator to leave a thread. Consider the fact that I could give you a warning for trolling but haven't as you already got a warning in this topic. - NMI

[Jefffar]

Well, technically it doesn't exist in the Robotech universe as it is not in the current edition of the books. So if you want people to quit discussing something that doesn't exist in Robotech, everyone would need to leave the thread.

However, some took exception with myself and others pointing out that the weapon in the old RPG would not have been a practical weapon for a veritech fighter if realistic physics were applied. Challenged to prove our assertions, we did so, proving that a 100mm tank killing weapon with a rate of fire in excess of 200 rounds per minute is not practical for use on an air (or land) vehicle as light as a Veritech Fighter.

Each time these assertions are challenged with less than complete proof of them being incorrect, its unlikely that myself or others who beleive in this position will respond.

However, the contention that realistic physics would make the weapon implausible does not preclude its existence in the Robotech universe, merely it requires that the Robotech universe does not adhere to realistic physics. If one accepts that the Robotech universe runs on an unrealistic physics regime, then there is no conflict between the positions of the GU-12 being implausible and of it existing in the Robotech universe.

[Jefffar]

So Jeff,
How many of your Ak-100 rounds (1020mm long overall, 147mm rim)) are you fitting into the Gu-12 gun body?

I'm eagerly anticipating your reply...

Ammunition fitting into weapons has never been a strong point of this universe (Mac II I am looking at you!) Why would we assume that this weapon is any different?

They payload of 78mm cannon shells on the Defender is a tad high and the magazine for the 180mm anti-mecha mortar of the Spartan and Tomahawk is also a rather difficult one.

Just more proof that the Robotech universe doesn't bother with things like realistic physics.

[obsessed]

Waay... No waay...

Duck season... Rabbit season...

Did too...did not...

*yawns*

Warning: User warned for spamming. - NMI

[eliakon]

Waay... No waay...

Duck season... Rabbit season...

Did too...did not...

*yawns*

Uhhhhh okay.......

[ShadowLogan]

So Jeff,
How many of your Ak-100 rounds (1020mm long overall, 147mm rim)) are you fitting into the Gu-12 gun body?

I'm eagerly anticipating your reply...

Ammunition fitting into weapons has never been a strong point of this universe (Mac II I am looking at you!) Why would we assume that this weapon is any different?

They payload of 78mm cannon shells on the Defender is a tad high and the magazine for the 180mm anti-mecha mortar of the Spartan and Tomahawk is also a rather difficult one.

Just more proof that the Robotech universe doesn't bother with things like realistic physics.

To be fair though, we only have one dimension for the rounds in question in the RPG (OSM is another matter, one I'm going to ignore). That means they could be using more energy dense materials and such to shrink the length w/o loss in performance.

[Jefffar]

So Jeff,
How many of your Ak-100 rounds (1020mm long overall, 147mm rim)) are you fitting into the Gu-12 gun body?

I'm eagerly anticipating your reply...

Ammunition fitting into weapons has never been a strong point of this universe (Mac II I am looking at you!) Why would we assume that this weapon is any different?

They payload of 78mm cannon shells on the Defender is a tad high and the magazine for the 180mm anti-mecha mortar of the Spartan and Tomahawk is also a rather difficult one.

Just more proof that the Robotech universe doesn't bother with things like realistic physics.

To be fair though, we only have one dimension for the rounds in question in the RPG (OSM is another matter, one I'm going to ignore). That means they could be using more energy dense materials and such to shrink the length w/o loss in performance.

It would take quite the shrink down. I'm not sure if the rounds and cartridges were spheres no bigger than the diameter of the weapon bore we could meet the listed ammunition loads of some of these weapons.

[glitterboy2098]

the recoil of a useful anti-armor 55mm round fired at over a thousand rds-pm still has staggering engineering implications for the VF-1..

though to be fair, i suspect the original creators of macross just didn't think about recoil.

[obsessed]

So Jeff,
How many of your Ak-100 rounds (1020mm long overall, 147mm rim)) are you fitting into the Gu-12 gun body?

I'm eagerly anticipating your reply...

Ammunition fitting into weapons has never been a strong point of this universe (Mac II I am looking at you!) Why would we assume that this weapon is any different?

They payload of 78mm cannon shells on the Defender is a tad high and the magazine for the 180mm anti-mecha mortar of the Spartan and Tomahawk is also a rather difficult one.

Just more proof that the Robotech universe doesn't bother with things like realistic physics.

To be fair though, we only have one dimension for the rounds in question in the RPG (OSM is another matter, one I'm going to ignore). That means they could be using more energy dense materials and such to shrink the length w/o loss in performance.

It would take quite the shrink down. I'm not sure if the rounds and cartridges were spheres no bigger than the diameter of the weapon bore we could meet the listed ammunition loads of some of these weapons.

First of all, this thread is about the preference between Gu-11 or Gu-12 gunpods. No place to discuss ADR and MBR ammo.

A spherical case and projectile ? Have you seriously chosen to ignore ALL knowledge of projectiles you possess? Do you comprehend WHY a pistol round is short and has a blunted rounded nose? Do you understand WHY rifle, cannon, and naval artillery are very long, very ogival noses, backed by long cases (or propellant bags)? Somewhere in the universe, you are suggesting that Overtechnology threw out paraboloid-nosed cannon and turned to spherical...dare I say cannonballs? Tha ADR is an anti-air platform NOT a cannonball "juggler"!

Please bring this thread back to the discussion to GUNPODS, please, before we stray too far.

[Jefffar]

It would take quite the shrink down. I'm not surenon-canocand cartridges were spheres no bigger than the diameter of the weapon bore we could meet the listed ammunition loads of some of these weapons.

First of all, this thread is about the preference between Gu-11 or Gu-12 gunpods. No place to discuss ADR and MBR ammo.

A spherical case and projectile ? Have you seriously chosen to ignore ALL knowledge of projectiles you possess? Do you comprehend WHY a pistol round is short and has a blunted rounded nose? Do you understand WHY rifle, cannon, and naval artillery are very long, very ogival noses, backed by long cases (or propellant bags)? Somewhere in the universe, you are suggesting that Overtechnology threw out paraboloid-nosed cannon and turned to spherical...dare I say cannonballs? Tha ADR is an anti-air platform NOT a cannonball "juggler"!

Please bring this thread back to the discussion to GUNPODS, please, before we stray too far.

Well, after thee problems of fitting realistically proportioned ammunition in the GU-12 were brought up, it was pointed out, with examples, that a number of different platforms from the Macross Saga have highly unrealistic ammunition capacities.

It was suggested that advanced technology might allow shorter rounds to fit the stated capacities. I then expressed my doubt that even impractically short rounds (ie sphere shaped) would be small enough to achieve the listed ammunition loads. This statement was a general statement including all weapons with unrealistic ammunition loads, such as the GU-12.

I am not sure how or why anyone would arrive at the conclusion that I believe the rounds are actually spherical. I am not sure why a discussion about mecha gunpods should preclude realistic assessments of their capabilities or their design constraints.

[Alrik Vas]

SO...if we assume Robotech doesn't adhere to realistic physics? I thought that was a given.