P-61 Gun-Laying Radar

[XBe02Drvr]

I was under the impression that the decision to use the F8U for close in combat was more of a decision based on the limits of the F4H? Regardless, I remember being told that the idea was to have the F4H's used (even in that case) to blow away a whole bunch of aircraft; then let the F8U's go in with their missiles and guns and cut-apart whatever was left?

The F8U was several years ahead of the F4H in the development / deployment process and the F4 was intended to extend the carrier's reach in both range and performance beyond what the F8 could do. The F8 was a contemporary of the F100 and F101 in the J57 family, while the F4H was brethren to the F104 and the A3J in the J79 clan.

I remember being told that the idea was to have the F4H's used (even in that case) to blow away a whole bunch of aircraft; then let the F8U's go in with their missiles and guns and cut-apart whatever was left?

That is in fact exactly the scenario for fleet defense against a saturation attack by standoff equipped high speed bombers. In the theoretical battle scenarios of the 1950s there was a sort of arms race going on between standoff range and speed vs interceptor speed, range, and search capability. The interceptors quickly got out to ranges beyond surface radar support, and had to be able to function without it, a concept entirely alien to the SAGE environment.

Like how if I didn't know the exact details how something worked but if I knew that "if I do this, then that and this -- this happens?"

Yup, they call that reverse engineering, and most nations with technological shortcomings get pretty good at it.

there was the USC-2 Datalink, which allowed the ability to remotely signal and maneuver an aircraft into a firing position

Back in my day, crews tended to take the data link with "a grain of salt", viewing it as a troubled technology. Though it was supposed to replace voice communication, it was still an emitter, subject to analysis, replication, disruption, and deceit by the opposition.

So they were jamming the airliner, then duplicating it and rebroadcasting it as their own?

No, there's no "stealth value" in jamming. That's like flashing a beacon and sounding a siren. You suppress the the airliner's transponder by slaving a signal to it, which cancels it out at the ground radar site. Since you (the bomber) are closer to the radar site, your transponder replies are both earlier and stronger than the airliner's, whose weaker signal, partially suppressed by your out of phase aping signal, is rejected by the radar's discriminator and yours is displayed on the scope. Neat trick, huh? A devious society creates devious minds which conjure up devious ways of deceiving simple minded westerners.
Cheers,
Wes

 

[Zipper730]

The F8U was several years ahead of the F4H in the development / deployment process

Of course, I just wasn't certain what the policy of the Defense Department & the Department of the Navy, and the CNO & NAVAIR, and the policies of the Fleet & Battlegroup Commands.

The F8 was a contemporary of the F100 and F101 in the J57 family, while the F4H was brethren to the F104 and the A3J in the J79 clan.

• F-100
  • First Flew: 5/25/1953
  • Entered Service: 9/27/1954
• F-104
  • First Flew: 3/4/1954
  • Entered Service: 2/20/1958
• F-101
  • First Flew: 9/29/1954
  • Entered Service: 5/2/1957
• F8U-1
  • First Flew: 3/25/1955
  • Entered Service: 1957
• F4H-1
  • First Flew: 5/27/1958
  • Entered Service: 12/30/1960
• A3J
  • First Flew: 8/31/1958
  • Entered Service: 6/1961

That is in fact exactly the scenario for fleet defense against a saturation attack by standoff equipped high speed bombers.

Basically it consists of waves of defense, though for offense, they had similar ideas actually involving the two aircraft.

In the theoretical battle scenarios of the 1950s there was a sort of arms race going on between standoff range and speed vs interceptor speed, range, and search capability. The interceptors quickly got out to ranges beyond surface radar support, and had to be able to function without it, a concept entirely alien to the SAGE environment.

Of course, the USAF controlled the territory it operated in so that wasn't as big a deal in theory (unless a radar site malfunctioned)

Yup, they call that reverse engineering, and most nations with technological shortcomings get pretty good at it.

It's logical thinking, plus I tend to think that way. I notice patterns and string them together. I of course ask others to make sure my conclusions were right...

No, there's no "stealth value" in jamming. That's like flashing a beacon and sounding a siren.

I was thinking more about suppression, though jamming is a usual way to suppress signals. In this case, the idea was to duplicate the signal and place yourself in such a location that your signal not only gets there and back first, but actually cancels the others out.

A devious society creates devious minds which conjure up devious ways of deceiving simple minded westerners.

I never thought of it that way -- though it definitely describes a great deal of certain societies. Also shows the reason to create a non-devious society.

 

[wrenchedmyspanner]

Do you ever wonder how people so advanced in their thinking they can come up with stuff like jet engines, fire control radar, angled carrier decks, optical landing systems, steam catapults, hydraulic arresting gear, etc, etc, etc,...ad infinitum, before anybody else, yet can't master such basic stuff as gaskets that don't leak and reliable generators, voltage regulators and aircraft and automotive electrical systems?
Cheers,
Wes

I had some trouble trying to recall how effective this system and couldn't find a reliable source online (go figure) but I did recall this rather excellent book:
Collier, R. and Wilkinson, R. (1990). Dark Peak Aircraft Wrecks 1 (Revised). Barnsley : Leo Cooper. p.95. ISBN 0-85052-457-1.

In reference to a period of time (early 1944) when Sir Lewis Hodges and Dickie Speare were posted to the RAF Development Unit at Newmarket. Sir Hodges, who had been responsible for tactical developments at Bomber Command, recalled Dickie Speare during that particular period.

"I visited the Bomber Development Unit both officially to see Dickie Speare and to go to the races. Dickie was instrumental in arranging for me to fly the Mosquito - which I hadn't done before - also the Halifax Mk III. Dickie and I were working on a new device called AGLT (Automatic Gun Laying Turret). It was a radar controlled gun turret that never did work very well."

Sorry, this is the incorrect post I am replying to.

 

[wrenchedmyspanner]

The British hadn't told them how to make it yet....

Automatic Gun-Laying Turret - Wikipedia

(I apologize for replying to a very early post but I did see this gun-laying system mentioned several times throughout this thread. I also initially replied to the wrong post!)


I had some trouble trying to recall how effective this system was and couldn't find a reliable source online (go figure) but I did recall this rather excellent book:
Collier, R. and Wilkinson, R. (1990). Dark Peak Aircraft Wrecks 1 (Revised). Barnsley : Leo Cooper. p.95. ISBN 0-85052-457-1.

This is in reference to a period of time (early 1944) when Sir Lewis Hodges and Dickie Speare were posted to the RAF Development Unit at Newmarket. Sir Hodges, who had been responsible for tactical developments at Bomber Command, recalled Dickie Speare during that particular period.

"I visited the Bomber Development Unit both officially to see Dickie Speare and to go to the races. Dickie was instrumental in arranging for me to fly the Mosquito - which I hadn't done before - also the Halifax Mk III. Dickie and I were working on a new device called AGLT (Automatic Gun Laying Turret). It was a radar controlled gun turret that never did work very well."

 

[Token]

Is that why the F3H's had a beam-emitter separate from the radar to guide missiles (the AAM-N-2 was a radar-beam rider, and was slaved to the optical sight).

I don't know. I have no first hand exposure to the AAM-2-N or its radar. However, spurred by this question in an attempt to research and at least familiarize myself with this system I found a lot of conflicting information.

Some (several) sources call the AAM-2-N Sparrow a beam rider, others (a lesser number) call it semi-active. I don't know which it was, but it is not horribly uncommon for someone not in the field to mistake the two.

I did not find mention of a separate emitter for the "beam rider", but I did find mention of a modified APG-51B to provide illumination. Illumination is used with a semi-active missile.

Looking at pictures of the missile I do not see rear facing antennas, which would probably be seen with a beam rider. And one article mentioned the "radome" of the missile and how it was shaped for high speed flight. This is consistent with a semi-active missile, which requires an antenna in the front to see the illumination of the target.

At a glance (figuratively) I would say it is more likely that the AAM-2-N was a semi-active missile instead of a beam rider. In either event, a "modified" APG-51B could have provided either beam riding or illumination. Boresight it (the APG-51) with the visual sight, keep the visual sight on the target, and the energy should provide either beam or illumination. And if this was not the way it was done, if there was indeed a separate emitter for the missile, the why not slave the separate missile emitter to the track of the APG-51?

Do you have any sources for details of the AAM-2-N system? Now that you have brought it up I would certainly like to fill in some missing information in my own thoughts on the system.

[quoteSo until the advent of single radar TWS, as a general rule, if you had one FCR radar on board (most fighters had one FCR, and it was often a fight to find the space and weight for that one) you could either be in a search mode or in a track mode, but not both at the same time.

I'm curious why they objected to this limit in WWII but not after?

[/QUOTE]

I am afraid I don't understand what you are asking here.

Which means it would be rapidly switching from search to track and back and forth at such an incredibly fast rate that to the human brain it would seem like it was all happening simultaneously.

For the most part, yes. Tracks would appear to be continuous and simultaneous to what else was going on. But in general a human can see the scan forming in the search operation of such systems. A phased array may make thousands of beams scanning an area of sky, and even at hundreds of beams (and most are slower than that) a second you can often still see such a system stitch the air picture together. Of course, if the system does not show an operator raw video, and all you see is processed track data, it can appear simultaneous and instantaneous to the user.

You end up divvying up power to produce the multiple beams?

You only have so much power, and if you want it looking at multiple locations truly simultaneously then you must share that power across those locations / beams. Advanced cognitive systems could tailor the power in each simultaneous beam (if it used such) to match the target dynamics or its anticipated dynamics.

For example, while making search beams you may want higher power to increase detection probabilities. But once a target is in track you could conceivably reduce power on the target (depending on several variables) to maintain a specific desired signal to noise ratio, possibly freeing up power for other uses.

But really, single aperture radars that do multiple truly simultaneous beams are uncommon, at best.

T!

 

[Zipper730]

Do you ever wonder how people so advanced in their thinking they can come up with stuff like jet engines, fire control radar, angled carrier decks, optical landing systems, steam catapults, hydraulic arresting gear, etc, etc, etc,...ad infinitum, before anybody else, yet can't master such basic stuff as gaskets that don't leak and reliable generators, voltage regulators and aircraft and automotive electrical systems?

That's actually a good point.

I don't know. I have no first hand exposure to the AAM-2-N or its radar. However, spurred by this question in an attempt to research and at least familiarize myself with this system I found a lot of conflicting information.

That's interesting

I did not find mention of a separate emitter for the "beam rider", but I did find mention of a modified APG-51B to provide illumination. Illumination is used with a semi-active missile.

Hmmm...

Looking at pictures of the missile I do not see rear facing antennas, which would probably be seen with a beam rider.

Are those similar to the 4 antennae on the RIM-8?

In either event, a "modified" APG-51B could have provided either beam riding or illumination. Boresight it (the APG-51) with the visual sight, keep the visual sight on the target, and the energy should provide either beam or illumination. And if this was not the way it was done, if there was indeed a separate emitter for the missile, the why not slave the separate missile emitter to the track of the APG-51?

I'm not sure, the only guess I can think of would be basically to allow one to continue searching for other targets while guiding the missile?

Do you have any sources for details of the AAM-2-N system? Now that you have brought it up I would certainly like to fill in some missing information in my own thoughts on the system.

Sparrow Missile Family by Andreas Parsch

I am afraid I don't understand what you are asking here.

I was just curious why they were worried about the gun-laying radar losing situational awareness when in tracking mode being a big deal with the P-61, and rectified with the F3D using multiple radars, and then not being a big deal after. It turns out they just used a bunch of radars anyway but simply made them smaller. RWR's also probably helped.

Advanced cognitive systems

It sounds almost like a little brain controlling the AESA...

 

[Token]

Are those similar to the 4 antennae on the RIM-8?

Talos I am on a little more solid ground with, having had some, if limited, first hand exposure to that system. More importantly I worked with several engineers and technicians who were deeply involved with that system, and we had many discussions touching on it.

I assume you are talking about the 4 little antennas that are on the front of the missile around the perimeter? Those antennas are not used in the beam riding part of flight, but rather those are the antennas for the final phase of flight, which is a semi active phase. The beam riding antenna is at the back of the missile.

At least for the non-nuclear version the missile starts out as a beam rider. Then as it closes on the target it transitions to a semi-active mode of operation. Beam riding simply does not give the accuracy required to intercept a maneuvering target at range. As was the case with several nuclear equipped missiles, extra accuracy was deemed unnecessary on the nuke version, so you don't see those 4 little antennas on that model, it is a beam rider all the way. What is the old saying? "Close" is good enough with horse shoes, hand grenades, and nuclear weapons.

I'm not sure, the only guess I can think of would be basically to allow one to continue searching for other targets while guiding the missile?

Possible. But I still find no mention of a separate beam riding emitter in the admittedly limited resources I have looked at.

Sparrow Missile Family by Andreas Parsch

A bit more data on the missiles themselves, but still pretty limited on the support electronics.

So the Sparrow 1 was a beam rider, but it was ineffective so it was short lived. Incidentally, RF beam riding missiles have always faced some hurtles, that is why it is not a popular technique. The Sparrow 2 was an active seeker, but never got much beyond a paper design and PDR. Active seekers are also a pain for some applications. Sparrow 3 was a semi-active seeker that was operational roughly 2 years after Sparrow 1 became operational, and this is the model that went into major use and developed into all the others of the related families.

T!

 

[Zipper730]

Talos I am on a little more solid ground with, having had some, if limited, first hand exposure to that system. More importantly I worked with several engineers and technicians who were deeply involved with that system, and we had many discussions touching on it.

I assume you are talking about the 4 little antennas that are on the front of the missile around the perimeter?

Yup

Those antennas are not used in the beam riding part of flight, but rather those are the antennas for the final phase of flight, which is a semi active phase. The beam riding antenna is at the back of the missile.

Do the antennae protrude out of tiny little fairings/blisters? It is very hard to find an image without the booster stage.

At least for the non-nuclear version the missile starts out as a beam rider. Then as it closes on the target it transitions to a semi-active mode of operation.

Was this from the outset or early on in the missile's development/operational life?

What function do the antennae serve? I was told it was some kind of interferometer...

Beam riding simply does not give the accuracy required to intercept a maneuvering target at range.

That makes enough sense -- the spotlight widens as you go further and further away from it.

As was the case with several nuclear equipped missiles, extra accuracy was deemed unnecessary on the nuke version, so you don't see those 4 little antennas on that model, it is a beam rider all the way. What is the old saying? "Close" is good enough with horse shoes, hand grenades, and nuclear weapons.

That's true -- a professor I had (Criminal justice) was a homicide detective, but he also was USAF reserve said almost the same thing except he said "nuclear war", and followed it up with "you can't talk about nuclear-war anymore" and I'm not sure if I said it or not, but my thoughts were basically "well, you can -- but people will think horribly of it"

Possible. But I still find no mention of a separate beam riding emitter in the admittedly limited resources I have looked at.

Well that clarified one thing...

So the Sparrow 1 was a beam rider, but it was ineffective so it was short lived. Incidentally, RF beam riding missiles have always faced some hurtles, that is why it is not a popular technique.

Accuracy at long range?

The Sparrow 2 was an active seeker, but never got much beyond a paper design and PDR. Active seekers are also a pain for some applications.

Like what?[/quote]

 

[Token]

Do the antennae protrude out of tiny little fairings/blisters? It is very hard to find an image without the booster stage.

No, there are no little visible fairings in this case, it is there, but it is really built in and not easily noticed. If you can find a clear image of the back of the missile sans booster you will see a small notch in the back ring, near #3 tail fin. That notch is the location of the antenna that looks back towards the beam source.

But remember the Talos is a pretty large missile and has a thick walled body to build things into. On smaller RF beam riding missiles there are typically blisters / radomes on the rear at some point, outboard of the exhaust cone and sometimes slightly forward. Some RF beam riders have put the antenna on the rear edge of the rear control / stabilization surfaces.

Was this from the outset or early on in the missile's development/operational life?

I have no idea if it was always conceived of as semi-active in the final phase of flight, but I think from very early in the design cycle this was a goal.

What function do the antennae serve? I was told it was some kind of interferometer...

Yes, they are an RF interferometer. They work in pairs to determine the direction of the received illumination energy from the target.

The illuminating RF reflects off the target, the RF interferometer determines the angle of arrival of that RF, and the autopilot steers the missile towards the reflection.

Accuracy at long range?

Roughly, the best accuracy you can achieve with a beam rider is the beam width at the target distance. Once the beam width at the target distance exceeds the kill radius of the warhead your kill probability goes down substantially.

Like what?

Like making sure you kill the target you mean to kill and not something else.

Active seeker missiles tend to fall into two categories, lock on before launch, or lock on after launch.

Lock on before launch makes everything good. You can direct the missile to start tracking the desired target, queue the missile to the current target location, confirm that the missile has locked onto a target, and also confirm the missile is on the right target, all while the missile is still on the rail. Launch it, and let it go do its thing, fire-and-forget.

But missiles tend to have limited power sources in flight. That means the on-board radar is not very powerful. And they tend to be small in diameter, limiting the size of the antenna, meaning low antenna gain. Both of these factors (and others) mean the radar on an active seeker tends to have limited range and there might be other, less costly and less complex, techniques you can use at such ranges.

So the more common approach is to have the missile on-board active radar take over for the last phase of flight only, and provide some other form of guidance for the first parts of the flight to get the missile within its limited radar range. There are several popular techniques, such as command guidance, beam rider, inertial nav, etc, that have been used for this mid-course guidance.

But now the missile is out there on its own, way down range, and it has to search for and acquire a target to intercept. And if you do your design job right, it will acquire something. But is it the right something? Your original target will have moved by then, and you can point the missile at a predicted location, but is that prediction still good? One technique is to let the missile go inertial nav and provide periodic telemetry to the missile to an updated target position. But then, if you are going to do that and keep tracking the target all the way to intercept (or just short of it) why not use one of the more simple (design) techniques like command guidance or semi-active all the way home. One real benefit is at relatively long ranges, when techniques like command guidance fall down in accuracy, or where the target might be actually outside the range at which you can keep energy on him, like below the horizon (this does not have to be a low altitude target, at long ranges very high flying aircraft might be below your radar horizon), so you cannot illuminate for a semi-active seeker.

Don't get me wrong, there have been successful active seeker AA and SA missiles, but they tend to be less common than command guided or semi-active. AMRAAM and Phoenix are two real successes. Active seekers are more common in SS and AS applications.

But we seem to have gotten pretty far afield of anything related to the P-61

T!

 

[fubar57]

But we seem to have gotten pretty far afield of anything related to the P-61 T!

Like that's never, ever happened before

 

[XBe02Drvr]

The XF8U-3 had much of the agility of the F8U-2, but with greater speed, longer overall range, and similar radar to the F4H

Uhh uhh! That's stretching it, my friend. There's no way you could stuff an equivalent to the F4's radar into the slender nose of the -3 Crusader. It's all about weight, volume, antenna diameter, and pilot workload. Antenna gain is one of the most important factors in radar range performance, and here, SIZE MATTERS. You couldn't put a dish the size of the F4's on the snout of the -3 without affecting supersonic performance and engine inlet air flow. Ever notice how long the schnozzola on the F4 is? It's all radar set, from the instrument panel bulkhead forward. On the E it's even longer, because they stuff an ammo drum in there as well. Now imagine trying to tack that on the nose of a -3.
Now imagine trying to operate that thing and fly the airplane at the same time. When you're in search mode, your eyes have to be riveted to that scope, because when the beam sweeps across a target, it makes a very small, very short-lived blip. If your eyes happen to be checking your flight instruments, your leader, or your wingman, you're going to miss it. The greater the range, the fainter and briefer the blip. If you're high Mach outbound and your target is likewise inbound, and your radar is doing its standard azimuth-elevation scan, you could be tens of miles closer to each other before your scan blips him again.
No, I think they made the right choice in buying the F4H.
Cheers,
Wes

 

[Token]

The production F8U-3 was supposed to get the APQ-50 radar, the same radar as the F4. But that never happened and would have required a rework of the radome, at the very least.

And there is a reason there are two people in the F4. The GIB is not there just because the pilot needs someone to hold his hand and tell him how great he is every few minutes, no, in addition to this critical pilot support requirement he also has to run the radar and the weapons systems.

Radar automation of the day just was not up to the task of doing it all by itself. You needed a human in the loop.

T!

 

[Zipper730]

Uhh uhh! That's stretching it, my friend. There's no way you could stuff an equivalent to the F4's radar into the slender nose of the -3 Crusader.

Actually, they could. They did it by moving the antenna further back in the nose where the diameter was thicker; then moving much of the electronic boxes into various parts of the fuselage.

According to Tommy H. Thomason's book on the XF8U-3 (ISBN-13: 978-0984611409), the proposal called for replacing the AN/APQ-50 with the A/N APQ-72 (same as the F4H). Another source states the plan was to use a radar called the A/N APQ-74

SIZE MATTERS

Size always matters -- with radar, and with women (I decided to remove some of the funnier stuff for fear of getting in trouble)

On the E it's even longer, because they stuff an ammo drum in there as well. Now imagine trying to tack that on the nose of a -3.

The F-4E's nose is of the same diameter only at at the back, at the section where the radar is joined, it's actually narrower as the A/N APQ-120 is of better performance despite the size reduction. The gun occupies the area behind the radar.

Now imagine trying to operate that thing and fly the airplane at the same time. When you're in search mode, your eyes have to be riveted to that scope, because when the beam sweeps across a target, it makes a very small, very short-lived blip. If your eyes happen to be checking your flight instruments, your leader, or your wingman, you're going to miss it. The greater the range, the fainter and briefer the blip. If you're high Mach outbound and your target is likewise inbound, and your radar is doing its standard azimuth-elevation scan, you could be tens of miles closer to each other before your scan blips him again.

The radar display could be heads-down, much the F-106, or heads-up. It basically displayed the radar data on the reflector site (it wasn't like a modern HUD that displayed airspeed/mach, heading, altitude), so one could avoid having to look down all the time. Also the radar computed the vectors and displayed a steering dot on the display for the pilot to maneuver it into position. They might have added additional automation by the time the aircraft entered operational service, but test-pilots (admittedly, they did work for Vought) seemed to be satisfied that it could be done by all Naval Aviators.

No, I think they made the right choice in buying the F4H.

The USN was mostly motivated by the twin-crew consideration over performance.

 

[Token]

According to Tommy H. Thomason's book on the XF8U-3 (ISBN-13: 978-0984611409), the proposal called for replacing the AN/APQ-50 with the A/N APQ-72 (same as the F4H). Another source states the plan was to use a radar called the A/N APQ-74

The way I understood it was they both could fit the APQ-50, but fitting the -72 was far easier for the F4H.

The APQ-50 just came up short with regards to range. Westinghouse determined that in order to get the required range the antenna size would have to grow from 24 inches to 32 inches (this equals about 2.6 dB of increased EIRP for the transmitter and about 2.6 dB more antenna gain for the receiver). The APQ-50 refitted with the 32 inch antenna is the APQ-72. To fit the APQ-72 to the F4H required a major rework of the radome, but relatively little to the frame structure itself.

With regards to the radar / electronic systems the F4H simply had more room to grow with less impact to the airframe.

The radar display could be heads-down, much the F-106, or heads-up. It basically displayed the radar data on the reflector site (it wasn't like a modern HUD that displayed airspeed/mach, heading, altitude), so one could avoid having to look down all the time. Also the radar computed the vectors and displayed a steering dot on the display for the pilot to maneuver it into position. They might have added additional automation by the time the aircraft entered operational service, but test-pilots (admittedly, they did work for Vought) seemed to be satisfied that it could be done by all Naval Aviators.

At that time the radar data displayed in the site was after an auto track was established. Someone had to look at the raw data in search scan, select a target, and place it in track. Then the target data could be in the site. Certainly it was possible for a pilot to do so, but the probability of detection was better with a dedicated RIO.

There is a vast difference between what a pilot can do in testing or in 1v1 and what he can do in a chaotic Mv1 situation. With a dedicated RIO the pilot can make the airplane do flying stuff and work on the primary target while the RIO can keep track of everything else, including potential threats.

The House Armed Services Committee agreed to fund new Navy fighter production for FY59, but only for a single new fighter. The Navy Air Board, on Dec 1, 1958, selected the F4H, in part because field testing had shown that even in a 1v1 situation a dedicated RIO would often see the radar target at up to 50% greater range than a pilot alone. He simply had more time to watch the search screen. Further, there was an increased likelihood that the dedicated RIO would maintain the track better than a pilot working alone, selecting the right radar modes more quickly as required. And in the event radar track was lost a dedicated RIO was more likely to reacquire in a timely manor. Later, when the AWG-10 was adopted, all of this became even more important.

The USN was mostly motivated by the twin-crew consideration over performance.

See above. The radar technology of the time simply was more effective with someone dedicated to its operations. The second crew member could spend all the time needed on the radar, and in addition was a second set of eyes in the aircraft even for visual targeting. There were some really good reasons for two people in the aircraft.

At that time in military aviation the work load on the pilot was increasing rapidly, and technology was not able to automate all the required tasks...yet. It is still, today, a bit of a balancing act.

I thought another factor in the decision was the weapons load. The F4H already had hard points for bombs, the Super Crusader had none, and would require significant redesign to accommodate them. The F4H carried 4 Sparrows, while the F8U-3 only carried 3.

And then there is the single vs twin engine situation. The Board apparently looked at accident rates and saw that twins had a much lower engine related accident rate, like one third. The twin engined F-101 had the lowest engine related accident rate of any of the century fighters and some of that data was available to them at the time.

T!

 

[XBe02Drvr]

And then there is the single vs twin engine situation. The Board apparently looked at accident rates and saw that twins had a much lower engine related accident rate, like one third.

During the three years I worked with the Phantom RAG squadron, there were 3 or 4 single engine landings a year, mostly due to flameouts associated with departures from controlled flight resulting from aggressive young nuggets cranking their turns a little too tight. Departures were pretty common in ACM training, and air relights didn't always work. With the F8U-3, each one of those would have been a splash.
As it was, the loss rate was about one a year, always in ACM, ordnance delivery, or carrier quals. The other phases of training never seemed to suffer losses.
Cheers,
Wes

 

[Zipper730]

The way I understood it was they both could fit the APQ-50, but fitting the -72 was far easier for the F4H.

The APQ-50 just came up short with regards to range. Westinghouse determined that in order to get the required range the antenna size would have to grow from 24 inches to 32 inches (this equals about 2.6 dB of increased EIRP for the transmitter and about 2.6 dB more antenna gain for the receiver). The APQ-50 refitted with the 32 inch antenna is the APQ-72. To fit the APQ-72 to the F4H required a major rework of the radome, but relatively little to the frame structure itself.

This might be a question that sounds bizarre, but how is it the F-106 managed to do almost as good as the F4H with a 24" radome?

The House Armed Services Committee agreed to fund new Navy fighter production for FY59, but only for a single new fighter. The Navy Air Board, on Dec 1, 1958, selected the F4H, in part because field testing had shown that even in a 1v1 situation a dedicated RIO would often see the radar target at up to 50% greater range than a pilot alone. He simply had more time to watch the search screen.

All that increased range by 50%?

 

[Token]

This might be a question that sounds bizarre, but how is it the F-106 managed to do almost as good as the F4H with a 24" radome?

What is your measurement of "almost as good"?

During Project High Speed the F4H APQ-72 radar consistently detected targets at longer range than the MA-1 of the F-106.

All that increased range by 50%?

That was apparently the finding of the Navy Air Board. I have never seen the raw data they worked from, however from my past experience I can see how this could be.

Someone who's primary tasking is to watch a radar screen is more likely to notice a weak or emerging return quicker than someone who is multi-tasking and only occasionally watching the radar screen. I have seen it happen time and time again. Additionally, there is a skill or art to watching and integrating the data from a radar screen. You really do get better with practice. Pilots are good at flying, RIOs are generally better at operating the radar. And some people are just better than others, period.

An example I have seen play out again and again:

When performing visually determined MDS measurements (Minimum Discernable Signal, a method to quantify a radars sensitivity) sometimes you must take into account who, what specific person, did the measurement. I have, often, seen two different operators take the same measurements within minutes of each other, and get very different results. The operators may be doing the measurement identically. But because part of the technique is an operator watching a scope and detecting a change in the noise floor on the scope, some operators eyes/mind just do a better job of integrating the noise in the noise floor, and they are simply better at detecting changes in that noise floor. And senior operators or technicians can almost always get "better" results than junior ones, just because of experience having trained their eyes and mind to see the target.

This is a common enough issue that I require the techs on any radar system I am involved with to record, by name, who did the visual detection (assuming that is applicable for that radar) during the MDS measurement.

T!

 

[XBe02Drvr]

Additionally, there is a skill or art to watching and integrating the data from a radar screen. You really do get better with practice.

My radar trainer had an adjustment for target return intensity which at any particular range would adjust anywhere between the weakest and the strongest return the real radar should be able to achieve on a fighter size target.
Early in the tactics phase the instructor RIOs would have me crank it to near max, and then as the students progressed through the syllabus, it would get adjusted downwards.
These students were fresh from their first exposure to AI radar, which was in a Marine T39 Saberliner equipped with an APQ-94 (F8) set with three operator stations. These were flown by Marine pilots while the A4 "targets" were Navy, and it turns out the Saberliner was a pretty good dogfighter, so promptly earned the title: "Barfoliner". I only saw one of those up close and personal and it had a persistent reek of ammonia and vomit. The pilots wore oxygen masks and helmets; the students and instructor did not.
Cheers,
Wes

 

[basil]

Gentlemen, excellent discussion and information.
Although also off-topic I always wondered about the maximum radar pulse power emission of fighter aircraft. Earlier ai-radars like the scr-720 had a peak power output in the region of 200 kW and ai radars of the 1950s and 1960s had even much more. Today's ai-radar outputs are described with normally less than 10 kW. I am aware that radar designers try to minimize the output power because of stealth but regarding the huge difference - is power output today measured in the same way as in earlier decades?

 

[PStickney]

Gentlemen, excellent discussion and information.
Although also off-topic I always wondered about the maximum radar pulse power emission of fighter aircraft. Earlier ai-radars like the scr-720 had a peak power output in the region of 200 kW and ai radars of the 1950s and 1960s had even much more. Today's ai-radar outputs are described with normally less than 10 kW. I am aware that radar designers try to minimize the output power because of stealth but regarding the huge difference - is power output today measured in the same way as in earlier decades?

OK - a couple of considerations - radar transmitter output gets two measures - Peak Power (Maximum Power per Pulse), and the Average Power. (Power over a period of time.)
Average Power depends on the source, of course, and the Duty Cycle - the amount of time spent resting/listening between pulses.
The power sources - Magnetrons, Klystrons, TWTs, and so forth, are basically putting out 'trons at the Average Power, which get stored up adn blasted out in very short bursts of the peak power.
Now - Pulse Radars, which have low duty cycles (for long range detection - they yell loud, then listen long) have high peak pulse values. Pulse-Doppler Radars, which require very high Pulse Repetition Frequencies to avoid things like blind speeds have very low peak pulse values, but a lot more pulses. If you were to calculate the Average Power values for a particular set of similar radars (Like the Pulse Radar on an F-4B Phantom, and the Pulse Doppler on an F-4J), you'd find that the average outputs are similar.