XF8U-3 Crusader III/Super-Crusader

[KJ_Lesnick]

Okay, I got some questions about the XF8U-3

- Question 1:  Since the aircraft had a datalink:  Was the plane able to be remotely vectored to the target area from the ground in a manner similar to SAGE?

- Question 2:  Since the radar proposed at least during the prototype stage, was an APQ-50 variant, and some variants of the APQ-50 (such as that used on the F4D/F-6 Skyray) did include the capability to automatically fly the intercept (the fire control system could take the data from the radar, and via connection to the aircraft's control surfaces, steer the aircraft into a firing position) -- Was the F8U-3's fire control system (albeit a different system than the APQ-50 -- the radar was an APQ-50, but it had a different fire control system) able to automatically fly aircraft into firing position, or did the pilot do that himself?

- Question 2A:  The APQ-50 on the F4D/F-6 Skyray also included the ability to automatically fire rockets (While the later F4D-1's had the ability to carry the AAM-N-7/AIM-9 Sidewinder -- they originally had unguided rockets as an armament) once the aircraft was within a pre-determined firing position.  Was that capability later upgraded to fire missiles (On the F4D-1); and did the F8U-3 (Assuming the fire control system could automatically vector the aircraft into optimum firing position) have the ability to perform an automated weapons release?

- Question 3:  While I think the F4H/F-4 was designed to be able to carry out intercepts without the need for a lot of ground-control radar-operator support, and could largely operate autonomously of such things, and the F8U-3 was designed to a lot of specifications that the F4H-1 was designed to (Originally they had the same radar, same missiles, were to have top-speeds similar to that of current land-based planes, and an intercept radius of 750 nm), was the F8U-3 designed to be able to operate under the same conditions (i.e. largely without the need of ground-control radar-operator support, or minimal ground-control support)?

- Question 4:  While only tangentially related here, it could yield me some information to work with (Assuming I can't get answers from questions 1-3) Since the F4H/F-4 originally had an APQ-50 radar and fire-control system (During the XF4H-1 and part of the F4H-1F stage) have the capability to automatically fly the intercept, and even perform automatic weapons releases or not? 

- Question 5:  Was the F8U-3 meant to be fitted with a bigger radar than the APQ-50, if it was to have entered operational service?


I'm not trying to sponge, I've found a variety of conflicting information on the F8U-3, or at least information that I've found ambiguous in this area.


Sincerely,
Kendra Lesnick

[Zen]

OK my memory for this is very poor, so don't ask for where I got this. But in the course of my reading I seem to reccal the following.

Q1, not sure its quite the same as SAGE. It should be able to guide the aircraft to the target certainly.

Q2, I think yes it did.

Q2A, not sure.

Q3, no, it needs a second seat for this, as is it was directed from the CiC, presumably much along similar lines to the UKs CDS directed by intercept positions in the AIO. Likely AEW was not upto the task for anything but a manual voice direction on its own, so it was dump the picture down the Carrier and give the task of pulling all the threads together to the CiC staff and systems.

Q4, don't know.

Q5, not that I'm aware of.

[GTX]

What if Vought offered a 2 seat version of the Super Crusader with bigger radar?



Yep, it's crude, but you get the idea.

Regards,

Greg

[rickshaw]

I didn't think the Super-Crusader could be made any more ugly.   I was wrong!   

[Jschmus]

If that monstrosity made it to squadron service, I can see it picking up the nickname "Durante".

[KJ_Lesnick]

F8U-3 -- Schnozzsader

[KJ_Lesnick]

I was thinking in regards to something posted on ElectrikBlue's "Blue-Sky Oddities" thread.  It was based on an actual A-7 concept (a supersonic A-7 variant) that had a lot of characteristics in common with the F8U-3

Link URL:  http://www.whatifmodelers.com/index.php/topic,22165.975.html
Image URL:  http://i703.photobucket.com/albums/ww37/jmsfbip/A-7U-3-variants.png

Regardless, the uppermost image lengthened back up to the F8U-3's size looks like it would make a great "Super-Twosader".  When Chance Vought proposed a twin-seated F8U-3; they found that it would require an increase in wing-area of 27-square feet, a gross-weight increase of 1,157 pounds, around 1,820 pounds when at gross-weight, an 9 square-foot increase in vertical fin area, 6-square feet on the ventrals, and an addition of 59 gallons of fuel.  Regardless, that design didn't have a cockpit configuration than this concept and there may have been some fuselage differences which I'm not sure what effect it would have; additionally if the plane was designed from the get-go as a twin-seater; it's possible that they would have been able to save weight this way than modifying an already extant design.  The projected length increase was 50 inches, I don't know what difference there would be in this particular case, but it's possible it might be a little more because of the raised canopy; the F-4 ended up growing two feet when the canopy was raised.

As for the radar, the APQ-74 could have been fitted with a 34-inch antenna over a 24-inch antenna; with the radar antenna mounted further aft in the nose, and the electronics moved further aft in the fuselage in order to avoid excess equipment in the nose (It did cause a reduction in fuel to do it however)

BTW:  Anybody know anything about the APQ-74?

[RB-211]

 Read a book by a chance/vought test pilot in the 90's, that had about as much info on the XF8U-3 as I've seen.This guy test flew corsairs during the war and was around til the LTV days.I can't remember his name.

[deathjester]

IIRC, the chaps name was John Konrad, Vought's chief test pilot

[skysurfer808]

Interesting thread about a plane I've long been fascinated by.

Q-1.  Not sure about the datalink a la SAGE.  Sage was designed to operate in a comprehensive Radar Station environment defending a fixed target rather then a moving group of ships at sea.  Instead, the 2 vs 1 man concept played a big role in the selection of the F-4 because of the backseater being able to act as a battle manager and radar operator.  Remember, even now, Navy backseaters refer to their pilots as Nosegunners.

Q-2   The F8U-3 would have had a form of lead pursuit tracking, with vectors provided via either via radio or some form of crude datalink. The backseater in-the Phantom performed vectoring services for the pilot.  The F8U-3 did have an early form of analogue Heads Up Display to assist single pilot operations. As far as autopiloting, the XF8U-3 was designed with 2 sticks, one of which flew the radar and one that flew the aircraft itself.  The autopilot allowed the pilot to concentrate on using the radar to track targets while the autopilot flew the plane.  Some form of auto release could have likely been included, though the design simulator had the pilot manually fire when the target was in range.  However, production models of the F-4 did not have an air to air auto weapons release capability, and in combat with restrictive Rules of Engagement, such a capability would likely have been counter productive.  Most likely some sort of dual mode release with manual override would have been incorporated....to save any friendlies from possible attack.

Q-3  The entire concept of a Carrier Battle Group is an early form of Network Warfare.  Carrier based AEW aircraft, ship based Radar, and other aircraft would all play a role, though most links were via radio and not through a comprehensive automatic datalink such as SAGE.   Remember too the Navy was trying to build a high degree of radar performance into its aircraft and would attempt to field the Douglas F6D Missileer in the early 60s as another answer to the Carrier Group's anti-bomber Outer Air Battle.  Still in combat, even in a low threat environment such as Vietnam, U.S. forces were heavily reliant on Ground Control Intercept capabilities such as College Eye Constellations and Red Crown at sea.  This reliance on GCI occurred even while flying 2 seater Phantoms.  

Q-4  Auto weapons release is a capability that sounds great, and in many cases the machine can perform better then the human.  However, having a human in the firing loop does have many advantages, leaving aside questions of morality.  A human is usually better able to determine friend or foe, while a crude analogue computer of the late 50's early 60's would have difficulties doing so.  Now adding other capabilities such as Combat Tree and datalinks would help.  The capability would be there, but likely coupled in a dual mode system.  Again, I don't know anything about the F-4 having auto weapons fire in air to air mode, though the F-4E's system does have a weapons release computer that calculates and determines optimal weapons drop trajectories for air to ground....in other words the plane would tell the pilot when to pickle ordinance.

Q-5  The F8U-3 would have likely received a bigger radar if it entered service, and would have benefited from advances in avionics technology throughout the 1960s and beyond.  This would have resulted in more compact transistor based avionics instead of old school vaccum tubes.  Just look at the way the Phantom's thick nose developed into the F-4E.  If the Crusader III had served as long as the Phantom it could have remained in service from the early 60s through the mid 1980s.   This would have been quite interesting from both a tactical and WHIF livery perspective....going from Gull Gray over White through Low Vis.

Keep in mind too the poor reliability of the Sparrow.  Combat records show a successful kill ratio of only 1 out of 12 firings, while the Sidewinder had one of about every 5.5 firings.  The second crew member of the Phantom and the extra Sparrow were certainly factors in the Navy's desire to buy the F-4 rather than the F8U-3.  If only they could have bought both and retrofitted the F8U-3 with an internal 20 mm vulcan instead of that stupid extra Sparrow.

I'm a bit of a freak when it comes to these things and the Super Crusader is the subject of a whole lot of whiffery in my mind.  Still, the program was killed before it could do more then show us all....what might have been.

Skysurfer808 aka William S. Cobb

loving planes since the 70s....flying em since 2001.

[rallymodeller]

Re Q4: The CF-100 (and other aircraft with the Hughes MG-4 fire-control system/radar) had automatic weapon release. Now, granted, it was rocket firing, but the entire lead-collision pursuit vector was for the most part flown automatically right through firing and into the past-target breakaway. Same goes for the F-102 and -106, which could, after vectoring by SAGE, fire their missiles automatically at the optimum point for maximum kill probability.

[skysurfer808]

Re Q4: The CF-100 (and other aircraft with the Hughes MG-4 fire-control system/radar) had automatic weapon release. Now, granted, it was rocket firing, but the entire lead-collision pursuit vector was for the most part flown automatically right through firing and into the past-target breakaway. Same goes for the F-102 and -106, which could, after vectoring by SAGE, fire their missiles automatically at the optimum point for maximum kill probability.

True on all counts, and the Avro Arrow would likely have been a Super SAGE machine...especially if Active Sparrows could have been fielded with it.  However, one factor left out of all this was the fact that in order to maintain a firing solution for Semi Active Radar Homing Missiles, Radar Lock needed to be maintained.  This would have been difficult for an autopilot to have maintained, especially with late 1950s technology.  Heat seekers or active homing missiles are one thing, but normal radar guided Sparrows would have required the firing aircraft to maintain radar lock and thus maneuver with the target until impact or the missile goes stupid and misses.  In this sense, the F8U-3 would have been superior as a kill platform as it was more maneuverable then the Phantom.  Auto weapons firing works great for area weapons such as rockets, but not so great for early guided missiles.

Skysurfer808 aka William S. Cobb

[KJ_Lesnick]

Skysurfer808,

Some form of auto release could have likely been included, though the design simulator had the pilot manually fire when the target was in range.

Makes sense

However, production models of the F-4 did not have an air to air auto weapons release capability

Really?  I didn't know that.  I can't imagine it was used very often.

The entire concept of a Carrier Battle Group is an early form of Network Warfare.  Carrier based AEW aircraft, ship based Radar, and other aircraft would all play a role, though most links were via radio and not through a comprehensive automatic datalink such as SAGE.   Remember too the Navy was trying to build a high degree of radar performance into its aircraft and would attempt to field the Douglas F6D Missileer in the early 60s as another answer to the Carrier Group's anti-bomber Outer Air Battle.

Wasn't the F-111B based on a similar concept (except with a supersonic dash in addition to the ability to loiter for awhile)?

The F8U-3 would have likely received a bigger radar if it entered service, and would have benefited from advances in avionics technology throughout the 1960s and beyond.  This would have resulted in more compact transistor based avionics instead of old school vaccum tubes.  Just look at the way the Phantom's thick nose developed into the F-4E.

On the F-4, the nose got skinnier not just because of a smaller radar, but because of having to wedge a gun into the plane; with the F8U-3, had it entered service, it would have been fitted with a 34 inch antenna recessed further aft in the nose; the electronics would have been re-positioned as necessary (mostly behind the pilot).  The F8U-3 would, in most likelihood not had a reshaped nose, the smaller radar would have simply been positioned forward in the nose.

[skysurfer808]

Wasn't the F-111B based on a similar concept (except with a supersonic dash in addition to the ability to loiter for awhile)?

The F-111B was a direct result of MacNamera applying his logic of commonality to the Navy's F6D Missileer concept.  The Navy deserves some blame for the ensuing disaster for coming up with the concept of a non-agile missile platform.  Certainly supersonic dash capability was a useful thing to have in the outer air battle, something the straight winged F6D did not have.  

However, the very idea of a missile only interceptor was proven flawed during Vietnam and subsequent conflicts.  Radar guided missiles eventually developed into reliable weapons systems, but for beyond visual range some sources say that only 3 air to air kills were achieved in true BVR conditions until the Gulf War.  Now the AMRAAM is everybody's favorite air to air system, but if it is ever compromised dogfighting may come back with a vengeance.  This makes Ssealth and agility important capabilities to have, if only to minimize detection range and dodge incoming missiles until the merge.  

On the F-4, the nose got skinnier not just because of a smaller radar, but because of having to wedge a gun into the plane; with the F8U-3, had it entered service, it would have been fitted with a 34 inch antenna recessed further aft in the nose; the electronics would have been re-positioned as necessary (mostly behind the pilot).  The F8U-3 would, in most likelihood not had a reshaped nose, the smaller radar would have simply been positioned forward in the nose.

I've read about that modification as well, and the only issue I can think of is the effect such a shift would have on the Aircraft's Center of Gravity.

This thread has caused me to do more detailed reading of the aircraft's systems.  I am fortunate enough to possess a PDF format copy of the Pilot's Guide for the third Super Crusader built by Vought.  This aircraft was considered to be the first production F8U-3, as opposed to a simple aerodynamic prototype.  It is not a fleet issue manual, but the cover says Chance Vought Aircraft Engineering Department, and it is listed as a preliminary Flight Guide for Navy type F8U-3 BuNo. 147085, with a date of 14 November, 1958.  This was a month before the Navy made its final decision in favor of the Phantom.  Therefore, this particular guide is a showcase of the capabilities expected to be built into production standard aircraft.

The Pilot's guide says the production machine would have been equipped with an Airborne Missile Control System capable of providing Radar tracking and Illumination of targets.  The AMCS was integrated with the plane's Air Data Computer which would supply data to both the AMCS and Automatic Flight Control System.  The AFCS had a 5 G positive and 1 G negative limit, and could be disengaged through the application of "firm" control forces.  According to the guide this would relieve the pilot of some of the flying tasks required to perform the intercept.  From what I see, the pilot flies the Radar stick which steers the system to Radar Lock On while the AFCS would actually be controlling the aircraft.  Therefore the pilot is in the loop, not quite hands off, but not hand flying either.  

The pilot would have to pull the trigger on the flight control stick to initiate what is called the automatic missile launch sequence, with a 1.1 second delay between pickle and firing.  Releasing the trigger automatically selects the next missile station.  I saw nothing about a truly automated missile launch system, or any mention of battle datalinks, this could have been classified at a higher level then the contractor was cleared for or indicates no such system was fitted or planned.  There was some mention of the APQ-74 as the production standard system, but for further information on that radar, it recommended going to the specific Westinghouse manual for the Radar.

Five indicator lights were located next to the radar screen, they were IN RANGE, meaning obvious, SNAP UP, showing proper range for snap up firing range, BREAKAWAY, to tell the pilot when to initiate a breakaway maneuver, and LOW ALT to warn when excessively low.  There was also an unused IR mode light.  A big X would also appear on the Radar screen to cue the pilot into initiating a breakaway.  No mention of any aural warning system, no Bitchin Betty from what I see.

Once a radar guided missile is launched the Pilot's Guide specifically states the pilot must continue pointing the aircraft at the target until impact.  The pilot could break away from a lead pursuit course but had to remain within the tracking limits of the radar antenna if firing a radar guided Sparrow III. Interestingly enough, the Guide also states that an IR Homing Sparrow III was available, and 4 Sidewinders were listed an a structural evaluation item for 147085, though these were not capable of being either launched or jettisoned.

Bureau number 147085 ended up being turned over to NASA at Moffett field after Vought lost to the Phantom.  She had only 13 hours of flight time prior to being transferred to NASA, but hardly flew once there due to problems with her augmented flight control system.  Whether this indicated a problem with her Auto Systems or Stability Augmentation System is unclear.  However, the overall goals for the aircraft's systems were ambitious for late 1950's technology, so whether her autopilot system would function as advertised is highly unlikely.  Autopilots can be infernal devices capable of all sorts of trickery even in the present.  

Finally, I looked up whether a production F8U-3 have supercruised....the Pilot's guide says no.  According to her performance charts, the peak cruise speed for the F8U-3 at full military power was in in the Mach 0.85 to 0.9 range, depending on altitude and configuration.  Therefore, the Super Crusader appears to have a performance level similar to today's Teen Series jets, with a higher top end speed.  She would have been a formidable dogfighter, as her overall flying qualities were highly praised by all during the Navy Preliminary Evaluation.

As far as a fighter, the F8U-3 opens the possibility for a lot of interesting whifs.  Could the Super Crusader have been the original Foxbat Killer, along with the F-12.  Would the Tomcat and Hornet been developed in their current forms.  Would a production F8U-3 been capable of Mach 2.5 plus, or would the weight and drag of armament have been more likely to have kept her top speed in the Mach 1.8-2 range...my vote is for the latter in view of the performance of the Phantom and Teen series.  The fact remains that the F8U-3 would have been an awesome flying machine, and therefore one of my favorite What If aircraft.

Skysurfer808

[KJ_Lesnick]

Skysurfer808

The F-111B was a direct result of MacNamera applying his logic of commonality to the Navy's F6D Missileer concept.

Commonality isn't intrinsically bad, so long as the design is built around the Navy's specifications as those are harder to meet.  Navy planes have to be structurally stronger, and have sturdier landing gears despite needing to be a reasonable weight, they have to have a wing-fold in many cases, they require good over the nose visibility (which generally favors the plane to land at a low AoA or at least low pitch angle if you have a variable incidence wing like the F-8); good directional control and roll-authority is required at low speeds regardless of gear position, good pitch control and the means to rapidly adjust the sink rate is also vital.  Technically the F-111B didn't handle as badly as one would think, but it was heavier than desired (84,000 pounds, 4,000 pounds over the maximum they wanted) and had to be stripped down quite a bit (The F-111A was supposed to be 85,000 pounds and ended up 100,000 pounds; the F-111B was supposed to weigh 80,000 and ended up 84,000 pounds).

The Navy deserves some blame for the ensuing disaster for coming up with the concept of a non-agile missile platform.  Certainly supersonic dash capability was a useful thing to have in the outer air battle, something the straight winged F6D did not have.

Correct.  I'm surprised the F6D wouldn't have been agile -- it was basically an enlarged F3D and despite being big, that plane could really move (though it was a bit underpowered)
 

However, the very idea of a missile only interceptor was proven flawed during Vietnam and subsequent conflicts.

Yeah, but the fact that the F-4 was not well suited for maneuvering at high altitudes did not help things out.

Radar guided missiles eventually developed into reliable weapons systems, but for beyond visual range some sources say that only 3 air to air kills were achieved in true BVR conditions until the Gulf War.

I didn't know that

Now the AMRAAM is everybody's favorite air to air system, but if it is ever compromised dogfighting may come back with a vengeance.

True, but there also is the AIM-9X and that thing is almost impossible to evade...
 

I've read about that modification as well, and the only issue I can think of is the effect such a shift would have on the Aircraft's Center of Gravity.

Could have been an issue, but it's possible that they positioned everything in a manner to avoid an excessive shift.

This thread has caused me to do more detailed reading of the aircraft's systems.  I am fortunate enough to possess a PDF format copy of the Pilot's Guide for the third Super Crusader built by Vought.  This aircraft was considered to be the first production F8U-3, as opposed to a simple aerodynamic prototype.  It is not a fleet issue manual, but the cover says Chance Vought Aircraft Engineering Department, and it is listed as a preliminary Flight Guide for Navy type F8U-3 BuNo. 147085, with a date of 14 November, 1958.  This was a month before the Navy made its final decision in favor of the Phantom.  Therefore, this particular guide is a showcase of the capabilities expected to be built into production standard aircraft.

Impressive

The Pilot's guide says the production machine would have been equipped with an Airborne Missile Control System capable of providing Radar tracking and Illumination of targets.  The AMCS was integrated with the plane's Air Data Computer which would supply data to both the AMCS and Automatic Flight Control System.  The AFCS had a 5 G positive and 1 G negative limit, and could be disengaged through the application of "firm" control forces.  According to the guide this would relieve the pilot of some of the flying tasks required to perform the intercept.  From what I see, the pilot flies the Radar stick which steers the system to Radar Lock On while the AFCS would actually be controlling the aircraft.  Therefore the pilot is in the loop, not quite hands off, but not hand flying either.

Better than being hands off, but HOTAS or a twin-man crew sounds more practical to me
 

I saw nothing about a truly automated missile launch system

That was a hunch based on the F4D (which launched it's rockets automatically within a certain range), the F-102 and F-106 which launch missiles in salvoes automatically once the plane reaches a certain distance.

or any mention of battle datalinks, this could have been classified at a higher level then the contractor was cleared for or indicates no such system was fitted or planned.

They might have deleted the datalink as the APQ-74 had a longer range radar and wouldn't have needed as much effort to direct itself to the target.

There was some mention of the APQ-74 as the production standard system, but for further information on that radar, it recommended going to the specific Westinghouse manual for the Radar.

I don't know where I'd find that honestly

Five indicator lights were located next to the radar screen, they were IN RANGE, meaning obvious, SNAP UP, showing proper range for snap up firing range, BREAKAWAY, to tell the pilot when to initiate a breakaway maneuver, and LOW ALT to warn when excessively low.  There was also an unused IR mode light.  A big X would also appear on the Radar screen to cue the pilot into initiating a breakaway.  No mention of any aural warning system, no Bitchin Betty from what I see.

If a visual cuing system was decently good enough (including arrows to give directional cues) would the automation have been necessary?

Once a radar guided missile is launched the Pilot's Guide specifically states the pilot must continue pointing the aircraft at the target until impact.  The pilot could break away from a lead pursuit course but had to remain within the tracking limits of the radar antenna if firing a radar guided Sparrow III.

That applies for all SARH missiles...

Interestingly enough, the Guide also states that an IR Homing Sparrow III was available

That's interesting, it makes sense though because there was often an advantage of firing a radar and heat-seaking missile to increase the odds of a successful impact.

and 4 Sidewinders were listed an a structural evaluation item for 147085, though these were not capable of being either launched or jettisoned.

The 4 sidewinders seem to be based on the F8U-2 set up...

Bureau number 147085 ended up being turned over to NASA at Moffett field after Vought lost to the Phantom.  She had only 13 hours of flight time prior to being transferred to NASA, but hardly flew once there due to problems with her augmented flight control system.  Whether this indicated a problem with her Auto Systems or Stability Augmentation System is unclear.

Augmented flight control system seems to most likely suggest SAS.

Finally, I looked up whether a production F8U-3 have supercruised....the Pilot's guide says no.  According to her performance charts, the peak cruise speed for the F8U-3 at full military power was in in the Mach 0.85 to 0.9 range, depending on altitude and configuration.

I was always under the impression that if you could fly between Mach 2 and 3, you'd probably be able to slip through the sound barrier a small amount with dry power alone.  Especially when you consider how streamlined that plane was (The F-104 could slip through the sound barrier even at low altitude with just 100% power.  Sounds nuts, but it's true.  No idea how far they could accelerate up to at altitude, but there seemed to be an implication that the burner was needed to accelerate it up to about Mach 2 for a supersonic cruise)

She would have been a formidable dogfighter, as her overall flying qualities were highly praised by all during the Navy Preliminary Evaluation.

Of course, it handled beautiful and didn't have some of the F8U-1/2's uglier handling problems