Air to Ground capabilities

[JB3DG]

6 hours ago, Northstar98 said:

Just had a look and yes, you're absolutely correct - corrected.

Toilet2000 is correct, in the diagrams for Dive Toss, Dive Laydown and Laydown in 1F-4E-34-1-1 (c. 1979, r. 1986), it states that the target is momentarily tracked visually. The radar is slaved to the optical sight's LOS in order to compute slant range.

A ground return only needs to be locked in radar/non-visual offset bombing (where the target is located at a known position relative to an identification point, for a radar identification point, the radar is locked onto said point, the WSO puts the radar into freeze and presses the target insert button, the aircraft then provides steering information to put it over the target).

As I recall though, to get actual A-G ranging into the system the WSO does actually have to go full trigger action on the A-G range return even though it is slaved to the gunsight. There's a chance he can end up locking a sidelobe return which will result in inaccurate ranging.

[Dragon1-1]

11 hours ago, KlarSnow said:

Of note that -34 refers to the backseater as the “pilot” and the front seater as the “AC” or “Aircraft Commander”

Actually, the nomenclature is "pilot/WSO" (although most would just call him a GIB) and "pilot" (earlier) or "AC" (later on). The former is because WSOs were technically trained to fly the aircraft (and the AC would sometimes let them hold the stick for a while ), so they were entitled to calling themselves pilots. Basically, it's a cultural thing, when the Phantom started out in the USAF they were both fully qualified pilots and that caused some issues, so to speak. So, to deal with that, WSOs were introduced, trained from ground up for the back seat job, but still capable of operating that stick and throttle in the back seat.

[Biggus]

11 hours ago, toilet2000 said:

1F-4E-34-1-1 (April 1979 with latest change in December 1986) page 1-119 and 1-120. Not sure if I can post any images or details since the revisions are post 1980, but it should be very straightforward for you to verify.

What @Northstar98 said is the gist of it and 100% accurate. You can definitely bomb à la A-4E in the DSCG F-4E that we'll get in DCS initially, without the WSO locking the ground.

 

Page 1-122 is quite explicit in the requirement for a lock-on though, isn't it?

Quote

Lockon must be acquired prior to actuating the bomb button.

It doesn't need to be maintained through the delivery, but it appears to me to be very much a part of the process to insert range information into the WRCS.

[toilet2000]

20 minutes ago, Biggus said:

Page 1-122 is quite explicit in the requirement for a lock-on though, isn't it?

Page 1-86C describes what "lockon" means in this context. It is not performed by the WSO and is automatically done to provide ranging information. It is again very similar to the A-4E where the radar scans the range gate until a significant return is detected along the boresight line. It does not do any angle tracking.

Edited November 14, 2023 by toilet2000

[Smyth]

18 hours ago, Northstar98 said:

Toilet2000 is correct, in the diagrams for Dive Toss, Dive Laydown and Laydown in 1F-4E-34-1-1 (c. 1979, r. 1986), it states that the target is momentarily tracked visually. The radar is slaved to the optical sight's LOS in order to compute slant range.

A ground return only needs to be locked in radar/non-visual offset bombing (where the target is located at a known position relative to an identification point, for a radar identification point, the radar is locked onto said point, the WSO puts the radar into freeze and presses the target insert button, the aircraft then provides steering information to put it over the target).

I think there may be some confusion in this thread related to the definition of "lock on". Designating a point on the 2-D radar map for non-visual bombing is separate from the air-to-ground ranging 'lock-on' procedure. For ranging we are only talking about the WSO selecting the correct strobe on a 1-D linear range sweep, after which the radar tracks range automatically.

31 minutes ago, toilet2000 said:

Page 1-86C describes what "lockon" means in this context. It is not performed by the WSO and is automatically done to provide ranging information. It is again very similar to the A-4E where the radar scans the range gate until a significant return is detected along the boresight line. It does not do any angle tracking.

Please read again, and also keep in mind my note above. The WSO is very specifically called out in the procedure, and is required to position the cursor over the correct strobe using the rear cockpit radar hand control. Agreed that angle tracking is not involved.

Here is my interpretation after careful reading, which I am sticking to unless there are real world F-4D/E WSO on here who disagree:

The pre-DMAS F-4E Dive-Toss technique is the same as the A-4 from the pilots perspective, assuming your back-seat driver is awake/alive/sober. The pilot tracks the target visually with the radar slaved to the optical LOS. Unlike in the A-4, the APQ-120 air-to-ground ranging mode requires the WSO to adjust the receiver gain and 'lock' the correct range return on the B-sweep at the start of the dive.

On the A-4 the APG-53/A radar set locks on automatically to enable single-pilot operation; in the two-seat F-4D/E, there was no need for an added computer. Just let the WSO earn his pay to save the weight, cost, and complexity of more 1960s electronics.

Alternatively the Pave Spike pod could provide laser range-finding when carried.

On DMAS and other upgraded Phantoms, the new digital computers are programmed to take full control of the radar for sophisticated air-to-ground ranging of the predicted impact point. Using commercial minicomputers as a benchmark, the performance-per-weight of digital processors had gone up over 50x from 1968 to 1978, allowing computing power to be spent on non-essential tasks. The fate of early 1970s avionics was to be totally obsolete in just a few years, although not necessarily useless.

For the DCS F-4E, HB could reasonably simplify the APQ-120 function and leave out that ranging procedure to save development effort for more important features. However I don't think it would be fair to take away the fun mini-game the WSO gets to play on his radar scope to distract from impending death while the 'Aircraft Commander' attempts to dive-bomb AAA emplacements.

As an interesting footnote, the slightly newer British AWG-11/12 fire control system appears to have some kind of automatic ground ranging lock-on, but still initiated from the rear cockpit.

Edited November 14, 2023 by Smyth
Responding to newer posts

[Biggus]

5 hours ago, toilet2000 said:

Page 1-86C describes what "lockon" means in this context. It is not performed by the WSO and is automatically done to provide ranging information. It is again very similar to the A-4E where the radar scans the range gate until a significant return is detected along the boresight line. It does not do any angle tracking.

 

It's only automatic after the WSO initiates lock-on.  The final paragraph on that page is very specific as to what the WSO must do to achieve lock-on.  @Smyth is right on this one.

[Northstar98]

6 hours ago, Smyth said:

I think there may be some confusion in this thread related to the definition of "lock on". Designating a point on the 2-D radar map for non-visual bombing is separate from the air-to-ground ranging 'lock-on' procedure. For ranging we are only talking about the WSO selecting the correct strobe on a 1-D linear range sweep, after which the radar tracks range automatically.

With you, apologies for the confusion.

[toilet2000]

17 hours ago, Smyth said:

I think there may be some confusion in this thread related to the definition of "lock on". Designating a point on the 2-D radar map for non-visual bombing is separate from the air-to-ground ranging 'lock-on' procedure. For ranging we are only talking about the WSO selecting the correct strobe on a 1-D linear range sweep, after which the radar tracks range automatically.

Please read again, and also keep in mind my note above. The WSO is very specifically called out in the procedure, and is required to position the cursor over the correct strobe using the rear cockpit radar hand control. Agreed that angle tracking is not involved.

Here is my interpretation after careful reading, which I am sticking to unless there are real world F-4D/E WSO on here who disagree:

The pre-DMAS F-4E Dive-Toss technique is the same as the A-4 from the pilots perspective, assuming your back-seat driver is awake/alive/sober. The pilot tracks the target visually with the radar slaved to the optical LOS. Unlike in the A-4, the APQ-120 air-to-ground ranging mode requires the WSO to adjust the receiver gain and 'lock' the correct range return on the B-sweep at the start of the dive.

On the A-4 the APG-53/A radar set locks on automatically to enable single-pilot operation; in the two-seat F-4D/E, there was no need for an added computer. Just let the WSO earn his pay to save the weight, cost, and complexity of more 1960s electronics.

Alternatively the Pave Spike pod could provide laser range-finding when carried.

On DMAS and other upgraded Phantoms, the new digital computers are programmed to take full control of the radar for sophisticated air-to-ground ranging of the predicted impact point. Using commercial minicomputers as a benchmark, the performance-per-weight of digital processors had gone up over 50x from 1968 to 1978, allowing computing power to be spent on non-essential tasks. The fate of early 1970s avionics was to be totally obsolete in just a few years, although not necessarily useless.

For the DCS F-4E, HB could reasonably simplify the APQ-120 function and leave out that ranging procedure to save development effort for more important features. However I don't think it would be fair to take away the fun mini-game the WSO gets to play on his radar scope to distract from impending death while the 'Aircraft Commander' attempts to dive-bomb AAA emplacements.

As an interesting footnote, the slightly newer British AWG-11/12 fire control system appears to have some kind of automatic ground ranging lock-on, but still initiated from the rear cockpit.

 

As far as I've read, you're absolutely right. My apologies for misunderstanding the -34.

[mkellytx]

On 11/12/2023 at 7:35 PM, toilet2000 said:

 

Dive Toss and Dive Level both don’t require the WSO to lock the ground with the radar. It works extremely similar to the computer bombing mode of the A-4E: you point the pipper at the target, pickle and then either proceed for a toss or a level bombing. Bombs are released automatically using the slant range from radar ranging at the initial pickle.

 

Highly recommend reading Palace Cobra.  Ed Rasimus flew 250 missions over NVN in the Thud and the Phantom and describes the use of dive toss in the Phantom.  Of note, it seems that the aircrew tended to only use the mode in lower threat environments, for high threat they would generally use manually depressed pipper for one pass and haul ass bomb runs,

[Dragon1-1]

That's presumably because the last thing you want to do when rolling in on a flak site is fly straight. In such a situation, they'd fly a curved approach, roll out wings level for a few moments just to drop the bombs, and then get out. They'd be in parameters, pipper on target, right as they rolled out. That's how it worked with F-100s, Thuds and Phantoms in most cases. Dive Toss would likely not work with such aggressive maneuvering.