Flightline: 63A

"user314" (user314) 10/20/2020 at 11:00 • Filed to: flightline, Planelopnik, planelopnik history

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More an addenda to yesterday’s post than anything else, this time I give you OV-10 Broncos fitted with gun turrets.

During the war in Vietnam, t he U.S. Marine Corps’ OV-10 Night Observation Gunship (NOGS) program modified two OV-10As to include a turreted forward-looking infrared (FLIR) sensor and turreted 20 mm !!!error: Indecipherable SUB-paragraph formatting!!! slaved to the FLIR aimpoint. The two lower sponsons were removed, and the cargo space behind the second seat was used to house the turret mechanism and ammo.

The two YOV-10Ds arrived in Vietnam on May 7, 1971 for combat evaluation with the !!!error: Indecipherable SUB-paragraph formatting!!! “Black Ponies” at !!!error: Indecipherable SUB-paragraph formatting!!! . Before & after the NOGS operated with the Black Ponies in 1971, average 20 mm ammunition usage was 5,138 rounds a month; from June 5 to August 13, 1971 the average usage went up to 50,527 rounds as the Black Ponies & NOGS fired 151,580 rounds. The YOV-10Ds flew 207 missions with 275 confirmed enemy kills and 23 injured, 63 sampans were destroyed and at least 30 damaged, 39 structures were damaged and 14 were destroyed, 19 secondary fires were noted and 36 secondary explosions were heard, 7 bunkers were destroyed and 19 damaged and 4 supply caches were destroyed/damaged. On January 31, 1972 155395 left VAL-4 at NAS Binh Thuy and returned to China Lake on February 1, 1972.

With the end of the Vietnam War, the NOGS YOV-10Ds were converted back to OV-10A standards or were placed in storage. The USMC later pursued the OV-10D again, this time without the turret.

Maxima Speed > user314 10/20/2020 at 11:06

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hmmm very interesting.

BaconSandwich is tasty. > user314 10/20/2020 at 11:08

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I've wondered why more aircraft don't have turrets like that. It'd make dogfighting a whole lot more scary. I realize there would be some aerodynamic effects of having a gun swinging around, but you'd think you could get a computer to automatically compensate.

TheBloody, Oppositelock lives on in our shitposts. > BaconSandwich is tasty. 10/20/2020 at 11:15

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I don’t think turrets work well on supersonic aircraft, although that’s just a thought from someone with no real knowledge on aircraft aerodynamics other than what I’ve read so take it with a grain of salt.

BaconSandwich is tasty. > TheBloody, Oppositelock lives on in our shitposts. 10/20/2020 at 11:20

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Quite possible. I wonder if the turret could be tucked away at higher speeds.

Chariotoflove > user314 10/20/2020 at 11:35

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Take away the cockpit and that looks like something Skynet would fly to wipe people out .

user314 > BaconSandwich is tasty. 10/20/2020 at 11:36

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Oh, there’s absolutely effects. The P-61 from WW2 had four .50 machine guns in a turret automatically aimed by the gunner or radar operator , but it caused enough drag and turbulence (especially in motion) that they were of marginal use.

Had we not developed missiles you might have seen more aircraft with turrets, but they’re of limited use by fighters or even attack aircraft at this point. Most APCs and tanks are armored against anything under 30mm, even from the top, and anything from the last 20 years or so are imm une to even 30mm   .

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > BaconSandwich is tasty. 10/20/2020 at 11:58

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B-24:

yes, it cleaned up the aerodynamics a bit when not in use, but it also added weight, complexity and intruded into the interior of the aircraft... the trade-offs were not worth it. the B-29 used low-profile turrets that didn’t have to accommodate the gunner due to remote control. That design both allowed a reduction in crew (or increase in guns per crew member) and reduced weight and interior space impact.

The concept has been toyed with for a long time...

But in aircraft where space, weight and aerodynamics are all at a premium, plus with the advancements in guided/steerable/seeking missile technology, a retractable turret just doesn’t make sense.

I seem to remember hearing about a gimbaled gun system on some fighter that added a just few degrees of movement to the cannon to allow the targeting computer to aid in lead/relative velocity/range compensations, but I can’t find anything about it right now...

edit: apparently experimental versions of the MiG15 and MiG17 were both fitted with moveable gun carriages for testing, the carriages only offered elevation control and were mea nt to compensate for range and turning radius during dog fighting,   but the design was scrapped with further developments in missile technology.

415s30 W123TSXWaggoIIIIIIo ( •_•))°) > user314 10/20/2020 at 12:00

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Slow but effective!

ttyymmnn > user314 10/20/2020 at 12:15

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Pretty sure that they just locked the turret forward and put all that lead downrange. All of it. 

ttyymmnn > user314 10/20/2020 at 12:17

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The YOV-10Ds flew 207 missions with 275 confirmed enemy kills and 23 injured, 63 sampans were destroyed and at least 30 damaged, 39 structures were damaged and 14 were destroyed, 19 secondary fires were noted and 36 secondary explosions were heard, 7 bunkers were destroyed and 19 damaged and 4 supply caches were destroyed/damaged.

These sorts of numbers are ALWAYS suspect. I’m not saying the 10D wasn’t effective, just that you have to take these body counts with a grain of salt. Pretty solid concept though. You would think that in today’s low intensity conflicts a system like this could be quite effective. I assume it’s quieter than an Apache. 

Turbineguy: Nom de Zoom > BaconSandwich is tasty. 10/20/2020 at 12:22

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A ballistic computer would have to compensate for off-axis firing anyway. I don’t know that a turret on a fighter would be any better than fixed cannons (or missiles) but it’d certainly add weight and drag so that’s probably why it’s not done. 

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > ttyymmnn 10/20/2020 at 12:47

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See also the Mil Mi-24/25/35.

A big, fast (a modified Mi-24 is still #2 on the world’s fastest helicopter registry, despite it’s size!), heavily armored helicopter with a gyro-stabilized turret gun which has been both extensively exported to banana republics and small dictatorships and extensively used in low-intensity combat to great effect. The Discovery Channel “Wings of the Red Star” episode on the Mi-24 talks about it’s use in Afghanistan. It was extremely effective against ground targets right up until the Mujahideen began utilizing MANPADS (both captured Soviet missiles, and CIA-supplied Stingers) to take them down. It was nearly totally impervious to 50cal (even the rotor blades are armored) and could shrug off hits from 20mm in non-vital areas. The Hind is often utilized in an attack role very similar to a fixed-wing airplane due to it’s speed.  It’s probably more accurate to compare an OV-10 with a turret to an Mi-24 than to compare an Mi-24 to other attack helicopters. The Mi-24 is also noted to be quite quiet by helicopter standards and pilots and gunners love it’s spacious, comfortable cockpit and well-laid-out controls.

facw > BaconSandwich is tasty. 10/20/2020 at 12:49

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Turrets were already falling out of favor by the end of WWII. Just a lot of size, weight, and aerodynamic inefficiency to commit to a weapon of limited utility (especially since you’d need at least two to not have a sizeable blind-spot).

In the age of missiles, they became even more irrelevant, dogfighting at gun range really isn’t a thing in modern air combat. I don’t believe there’s been a fighter shot down by guns since the Falklands war, and even then probably only because the Harrier didn ’t carry much of an a ir-to-air payload and the Argentine wasn’t even really shot down, it made it back to base but the pilot ejected rather than risk a landing with damaged gear (The Russians did just shoot down one of their own fighters, but only because someone forgot to remove the live ammo before dogfight training).

I do wonder if it would make sense to add some sort of automatic point defense to EWACS and tankers. Those vulnerable support aircraft are going to be high-priority targets in any war against peer or near-peer state, so it seems like it could be worth some deoptimization of their flight performance to make them less vulnerable. There’s been talk of stealth tankers, which might help there, but there’s only so much you can do to hide an EWACS plane, whose job is to blast our huge amounts of radar.

ttyymmnn > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 10/20/2020 at 13:13

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Basically a flying infantry fighting vehicle. 

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > ttyymmnn 10/20/2020 at 17:02

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T hat was the design intent, but in practice they found it was most vulnerable at the times it was landed, loading or unloading troops, accounting for most losses . It was fast and surprisingly nimble once in the air under way (the stub wings actually provide lift and could take as m uch as 25% weight load off the rotor at speed) , but heavy and ungainly at slow/hover speeds. As a result operators often stripped out most of the troop armor to save weight, stashed extra ammo and munitions in the back , and loaded more rockets onto the hardpoints. They then stationed a single “technician” who’s job it was, ostensibly to reload the weapons between assault runs, but who also ran one or two additional machine guns placed in window mounts at the rear of the chopper, t hus making it a hulking, heavily armored, 3-man- crew fast attack gunship. This was/is , by most accounts, it’s most successful iteration. It could still be used as an emergency extraction transport in this configuration once the extra ammo was used or dumped , but it was found that delivering troops by ground transport , ESCORTED by Hinds was much safer and more effective. L ater models moved to 20 or 30mm autocann on in the nose turret, as the original 12.7mm gatling gun didn’t provide enough penetration to take on well armored vehicles, entre nched positions, or light tanks. These later targets being more in line with it’s shifting role to gunship.

this ramble is almost completely off topic, except that I agree with your statement that something like an OV-10 with a turret would be useful. T he Mi-24/25/35 sort of is that, even though it’s a helicopter, and it has proven quite useful.

I also just love that such a huge, ugly helicopter is also fast as hell. T he entire airframe, down to the landing gear, is subtly a symmetrical to aid in high-speed handling and counter rotor torque at high loads. The S oviets made some damn fine rotor craft.

ttyymmnn > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 10/20/2020 at 17:05

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The entire airframe, down to the landing gear, is subtly asymmetrical to aid in high-speed handling and counter rotor torque at high loads.

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > ttyymmnn 10/20/2020 at 17:22

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Quick cut-paste from wiki:

The main rotor was tilted 2.5° to the right from the fuselage to compensate for translating tendency at a hover. The landing gear was also tilted to the left so that the rotor would still be level when the aircraft was on the ground, making the rest of the airframe tilt to the left. The tail was also asymmetrical to give a side force at speed, thus unloading the tail rotor.

Result: neutral hover despite huge rotor area, high yaw authority even when the main rotor is loaded at speed, lower tail-rotor power requirements, leaving more of the total 4400shp to drive the main blades .

ttyymmnn > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 10/20/2020 at 17:26

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That’s cool. Thanks.

gmporschenut also a fan of hondas > BaconSandwich is tasty. 10/20/2020 at 23:04

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https://en.wikipedia.org/wiki/Blackburn_Roc

https://en.wikipedia.org/wiki/Boulton_Paul_Defiant

https://en.wikipedia.org/wiki/Hawker_Hotspur

British had quite an interest in the late 30s. problem is they add a fair amount of weight (2nd crewmember) and often quite big in drag.

“ Luftwaffe fighters suffered losses when “bouncing” flights of Defiants from the rear, apparently mistaking them for Hurricanes. [24] The German pilots were unaware of the Defiant’s rear-firing armament and encountered concentrated defensive fire. The Luftwaffe changed tactics, to outmanoeuvre the Defiant and attack from below or dead ahead, where the turret guns offered no defence. Defiant losses quickly mounted, particularly among the gunners, who were often unable to leave stricken aircraft. The additional weight of the turret and the second crewman plus the aerodynamic drag gave the Defiant a lower performance than conventional single-seat fighter aircraft.”  https://en.wikipedia.org/wiki/Boulton_Paul_Defiant#Air_combat