Gunship Doctrine: Would a AC-47 be any good in WWII?

[ShVAK]

(My first post, yay)

I have a big interest in the interesting and underrated medium bombers that the U.S. fielded as gunships--the B-25G, -H, -J "solid nose" variants, the A-26B, the A-20G--and also the DC-3/C-47 that ended up being a low cost and VERY effective gunship conversion over Vietnam and in the air forces of several developing nations (Columbia still uses them in the COIN role to take out drug trafficking ops).

So I was wondering--would a AC-47 Spooky be any good in WWII, going by the doctrine of the time or would it have been easy meat for fighters or just plain ineffective etc. etc. Obviously the USAAC wouldn't have access to the M134 Minigun as they were post-war, but feel free to substitute .30 cal Brownings or even .50 cal or 20mm cannon (yes, they fit.... barely) in any combination you think would be feasible.

Here be specs:

AC-47 Spooky

General characteristics

Crew: 8: pilot, copilot, navigator, flight engineer, loadmaster, 2 gunners and a South Vietnamese observer
Length: 64 ft 5 in (19.6 m)
Wingspan: 95 ft 0 in (28.9 m)
Height: 16 ft 11 in (5.2 m)
Wing area: 987 ft² (91.7 m²)
Empty weight: 18,080 lb (8,200 kg)
Loaded weight: 33,000 lb (14,900 kg)
Powerplant: 2 × Pratt Whitney R-1830 radial engines, 1,200 hp (895 kW) each

Performance

Maximum speed: 200 kn (230 mph, 375 km/h)
Cruise speed: 150 kn (175 mph, 280 km/h)
Range: 1,890 nmi (2,175 mi, 3,500 km)
Service ceiling: 24,450 ft (7,450 m)
Rate of climb: ft/min (m/s)
Wing loading: 33.4 lb/ft² (162.5 kg/m²)
Power/mass: 0.15 hp/lb (240 W/kg)

Armament

Guns:
3× 7.62 mm General Electric GAU-2/M134 miniguns, 2,000 rpm or
10× .30 in Browning AN/M2 machine guns
48 × Mk 24 flares

Conversely: Would any of the above medium bomber-based gunships do well in Vietnam sorties or were they ill-suited for that purpose? Obviously the gunship concept circa 60s-70s was very successful but there were key differences (i.e. waist guns instead of nose guns, transports with big roomy fuselages instead of fast bombers, emphasis on loiter time rather than quick interdiction).

Discuss!

 

[R Pope]

Spooky wouldn't have had much of a chance in the European skies when squadrons of real bombers were getting decimated even when escorted by Mustangs et al.

 

[mikewint]

I well remember the gunships. Early versions of the c-47 fitted with ten .30 caliber AN/M2 machine guns were tried but they did not have the density of fire necessary. The 3 mini's could put a bullet every square yard over an entire football field in 3 sec. not to mention the illumination flares and its huge loiter time.
The big bird would be easy meat for fighters so air superiority is a must

 

[tyrodtom]

Not just easy meat for fighters, but easy meat for AA.
The AC-47 flew in a left hand turn shooting toward the center of the banked turn, too regular a target for survival in any kind of AA enviroment.
They're way off on the rof of those miniguns, the lowest rate is 2000rpm, high rate 4000. Some versions higher, as high as 6000rpm+.

Even the more modern AC-130, , much faster, flying much higher, and with lots of countermeasures aboard, were shot down over the Ho Chi Minh trail.

 

[Tante Ju]

The Spooky was very effective against guerilla type fighters with only small arms, however against regular armies, I do see a problem... actually four, see below.

 

[norab]

might have had a limited role in the Pacific against banzai type charges or small boats, barges ,etc or harassing small island garrisons

 

[davebender]

Same problem during WWII as today. They are easy targets for 20mm, 25mm (i.e. Japan) and 37mm ground fire. So aircraft like the AC-47 can only be used against enemy forces who have no AA guns.

 

[mikewint]

Might argue a bit about AA. At night AA tracer fire pinpoints the AA battery and the miniguns could and did blanket that area with tons of supressive fire. Fighters were also available both jet and prop. In Vietnam Of the 53 aircraft converted to AC-47D configuration, 41 served in Vietnam and 19 of those 41 were lost to all causes with just 12 of those 19 lost in combat. Combat reports indicate that no village or hamlet under Spooky Squadron protection was ever lost to enemy action.
Puff was a very specialized tool but very effective in its role. Spooky gunships were instrumental in breaking the 3rd NVA batallion's back at our camp at Bong Son along with 1st cav, ARVN and Korean forces the entire area was surrounded and the NVA batallion destroyed.

 

[ShVAK]

might have had a limited role in the Pacific against banzai type charges or small boats, barges ,etc or harassing small island garrisons

That's what I was thinking. Doubt it would've been very successful in the ETO due to fighters (at least without a decent escort, even in night operations) and heavy AA but someplace like Southeast Asia and areas of the PTO where they'd likely be facing lesser-equipped opposition it might've fared well.

I think the ideal armament would've been 4-5 .50 cal Brownings (the AN/M2 model), maybe even with provision for water jackets as some of the very early or naval M2's had for more continuous fire. They wouldn't have the insane ROF of Miniguns but could compensate with better hitting power and range.

 

[Jabberwocky]

That's what I was thinking. Doubt it would've been very successful in the ETO due to fighters (at least without a decent escort, even in night operations) and heavy AA but someplace like Southeast Asia and areas of the PTO where they'd likely be facing lesser-equipped opposition it might've fared well.

Even then, I'd be reluctant to commit the aircraft to front line operations. The amount of light and medium AAA available to the Japanese was actually quite significant and their light AAA (the 20 mm Type 98 and 25 mm Type 96, in single double or triple mounts) were considered very effective.

Maybe as part of 'mopping up' and dealing with secondary areas of resistance.

I think the ideal armament would've been 4-5 .50 cal Brownings (the AN/M2 model), maybe even with provision for water jackets as some of the very early or naval M2's had for more continuous fire. They wouldn't have the insane ROF of Miniguns but could compensate with better hitting power and range.

I'd suggest that there were several weapons that would have been better than a handful of M2s. The M1A2 37 mm anti-aircraft cannon was readily available by 1941, and came with AP and HE rounds. It would provide greater standoff range and a much better usefulness against any light armour or hardened targets (bunkers ect) that presented themselves. The obvious drawback is the weight of the weapon and the low rate of fire (150 rpm)

There was also the 20 mm L70 Oerlikon. Again, it has the drawbacks of weight and rate of fire compared to the .50, but comes with a variety of ammunition and was both very powerful and exceptionally reliable.

I'd suggest a 37 mm M1A2 gun twinned with a pair of .50s (as it was used in real life) and a twin 20 mm Oerlikon set-up would be better than 4-5 .50 cals. This gives you a variety of options to deal with a variety of targets, both AP and HE performance and a high RoF option as a fall back position.

 

[norab]

they might have been able to adapt the small 75 MM used in the B-25's also

 

[ShVAK]

they might have been able to adapt the small 75 MM used in the B-25's also

I was thinking of that but wasn't that gun often removed in the field in favor of more .50's? There had to be a reason for that, if I had to guess low rate of fire, unreliability or both.

Also not sure where you'd mount it. It seems like it would be too big to mount on the side of a C-47 without drastically affecting CG, airframe stress etc. but I could be wrong.

 

[ShVAK]

Good post, I like the 37mm/.50 combo though I don't know how good the Spooky would've been attacking hardened targets. Anti-personnel, sure, but circling a bunker with any kind of defensive AA installations would've been tricky for a big slow bird. Probably could make up for it with accuracy, though--in a pylon turn a slow-firing cannon would've been easier to keep on target compared to the kind of fast strafing/shallow dive runs the B-25 would've done with its 75mm.

Didn't the Oerlikon have trouble with jamming in aircraft applications?

 

[norab]

maybe multiple modified versions of this

M18 recoilless rifle - Wikipedia, the free encyclopedia

with the exhaust gases vented outside the fuselage, very low weight (less than 50 pounds) and virtually no recoil (could be shoulder fired by a single soldier)

 

[tyrodtom]

maybe multiple modified versions of this

M18 recoilless rifle - Wikipedia, the free encyclopedia

with the exhaust gases vented outside the fuselage, very low weight (less than 50 pounds) and virtually no recoil (could be shoulder fired by a single soldier)

I wonder what that jet of gas vented out the side would do to the flight path. Like somebody said on here, I think mikewint, recoiless rifles, ain't.

 

[davebender]

That would allow 20mm and larger flak to open fire before the Spooky .50cal machineguns were in range.

 

[tyrodtom]

The later AC-130 was fitted with the 20mm Vulcan cannons, 40mm Bofors, and one, maybe more had a 105 mm cannon. So it had great standoff range, but even so with the extreme AA enviroment on the HCM trail, 6 were lost.

Is there any reason a WW2 era AC-47 couldn't be fitted with the Bofors?

The main problem with this type of attack, is while aiming fire out the side in a pylon turn makes for very simple aiming solution for the pilot, it's also a very simple aiming solution for any AA on the ground.

 

[ShVAK]

Is there any reason a WW2 era AC-47 couldn't be fitted with the Bofors?

My guess is that it would be too heavy and stressful on the C-47 airframe. A Bofors weighed 2 tons in L/60 form. An M134 weighs 85 pounds and the USAF version had three. And we're still not taking into account the weight of all the ammo, etc.

A quartet of .50s would be very easily doable (and was done with some foreign variants of AC-47), a pair of 20mm would be as well but anything bigger would probably be pushing it.

 

[tyrodtom]

My guess is that it would be too heavy and stressful on the C-47 airframe. A Bofors weighed 2 tons in L/60 form. An M134 weighs 85 pounds and the USAF version had three. And we're still not taking into account the weight of all the ammo, etc.

A quartet of .50s would be very easily doable (and was done with some foreign variants of AC-47), a pair of 20mm would be as well but anything bigger would probably be pushing it.

The L/60 is the 4 wheeled platform, elevating and traversing system,and sights. All you need for the aircraft is the gun and recoil mechanism, that could be half of that, but still pretty heavy. The L70, a postwar Bofors list a gun weight of 560kg, about 1250 lbs.
I'm just trying to think of something that would keep it out of intimate range of ground AA.

 

[Shortround6]

The AC-130 also has quite a suite of sensors for target detection and aiming, unlike the wad of gum stuck on the side window of the "Spooky's". OK an exaggeration but there is a world of difference between the detection and aiming capabilities of an AC-130 and any WW II ground support or attack plane. It doesn't matter if you have a 40mm Bofors if you can't aim it or see the target from 2-3000 meters.

Just mount 3 to 6 pairs of the .30 cal Browning from the rear seats of Dauntlesses or SB2C's, they cycled at about 1200rpm ( twice that of the ground guns) so a pair should equal the mini gun on slow speed. 6 pair should give 240 rounds per second which should take care of anything that isn't armored or buried in a bunker.

Long range shooting or point targets like tanks or small bunkers require aiming systems that didn't exist in WW II.