Christopher Wang

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In the January 16, 2020 article "Triplesonic Interceptors: The F-103, F-108, and YF-12A", Tony R. Landis of the Air Force Material Command History Office briefly mentioned an "I-70" interceptor version of the North American Aviation XB-70 Valkyrie. According to Landis (2020), the "I-70" was evaluated against both a Convair B-58 interceptor concept and the NAA XF-108 Rapier as part of the XF-108 program's development during the late 1950s (p. 3).

Does anyone have more information about an interceptor version of the XB-70 Valkyrie?

Source:
Landis, T. R. (2020). Triplesonic interceptors: The F-103, F-108, and YF-12A [PDF]. AFMC History and Museums Program. https://media.defense.gov/2020/Jan/16/2002235686/-1/-1/1/FLASHBACK_INTERCEPTORS.PDF
 
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Would have to be a BVR missile truck, given turning circle...
Pye Wacket* was supposed to be an anti-missile missile, so it should be capable of air to air. I believe the payload was 6 in a bay, so up to 12 of them. Would that qualify as a truck? It would certainly have the range for the job.

*I know AIM-47 was the likely armament, but I just like the visual of interceptor Valkyries flinging missile 'Frisbees' at incoming Soviet bombers.
 
Any images available? I'd imagine that the Valk would receive plenty of modifications to accommodate the AN/ASG-18 fire control system required for guiding the AIM-47 Falcon missiles.
 
Lenticular designs can take severe turns.
In August 1958, the North American project office submitted the proposal Defensive Antimissile System (DAMS) using air-to-air missiles launched by the Valkyrie.

The Defense Feasibility Study was completed in March 1959 and published by the Air Proving Ground Center-Eglin AFB the same month the U-2 incident occurred.

In 1948 the first experimental AAM-A-2 air-to-air missile was launched and entered in service with the USAF in 1955 as the Hughes AIM-4 Falcon.

The original purpose of the Falcon was a Mach 3.8 self-defense weapon for the B-52 bomber and was shortly revived during the B-70 development. The rail-launched missile was not a particularly maneuverable and needed to be pointed in the right direction of the target.

Due to the B-70 speed the Falcon could just be used against any threat coming from its forward hemisphere, but the Valkyrie would have to defend itself against threats from all direction with spherical coverage.

The Falcon was a cylindrical rocket with four delta wings. Would it have been thrown sideways from a B-70 flying to Mach 3 it would have been destroyed by the crosswind shock waves.

North American proposed the Weapons System WS-740A, a wingless lenticular-form rocket with omnidirectional launch capabilities, capable of engaging incoming missiles at relative speeds of Mach 10 and being able to survive and maneuver at 250g accelerations.

The project was awarded to the Convair Division of General Dynamics Corporation, under the codename Pye Wacket in June 1959.

A general aerodynamic evaluation was conducted to determine the technical feasibility of lenticular cross section/circular planform configuration. Wind tunnel tests with several 1/3 scale models were conducted in the Arnold Engineering Development Centre.

The results indicated that the lenticular configuration with blunted trailing edge, sharp leading edge and modified tangent contours, have best aerodynamic characteristics than the symmetrical lenticular cross section, and the most desirable volume distribution for the propulsion system.

The lenticular configuration was efficient at hypersonic velocities with good maneuverability at altitude. Additional tests demonstrated that the aerodynamic controls are not suitable for use in the omnidirectional launch phase of flight, due to the necessity of alignment with the relative wind.

One reaction-jet control system was used, control in yaw, roll and pitch could be obtained by means of the thrust forces generated by four nitrogen-injected binary thrusters, with exhaust through the top and bottom surfaces of the disc.

Pye Wacket had an inertial midcourse guidance system with terminal infrared homing. The Redeye IR seeker was mounted in the leading edge behind an IR window with a look angle of 40 degrees and cooling system.

The USAF determined that internal carriage of eight wingless missiles could be installed in the Valkyrie with no range penalty.

The weapon was to be structurally rigid to withstand extremely high launch accelerations, rapid change of thrust direction for quick maneuver, maximum flight duration of 50 seconds, cruising at Mach 6.5+ and terminal velocities of Mach 10.

The expected aerodynamic heating of 3,300 ºF at 11 seconds of flight, requires the use of a leading edge made of Pyrographite. The outer skin of the disc was made of polyester resin, with Titanium B-120 alloy honeycomb core, protected by a layer of Teflon ablating material to restrict skin temperatures to under800ºF. The internal structure was made of magnesium-alloy.

Three Pye Wacket configurations were proposed in 1961:

60-inch diameter, 21 per cent thickness-to-chord ratio configuration

Power plant: three Thiokol M58A2 solid-fuel rocket motors with 10,200 lbf thrust each. Launch weight: 830 pounds. Warhead: one W54 nuclear device with 50 pounds weight. Range: 100,000 ft at 60,000 ft altitude.

60-inch diameter, 14 per cent thickness-to-chord ratio configuration

Power plant: one integral pancake-shaped solid-fuel rocket motor with 9,700 lbf thrust. Launch weight: 581 pounds. Warhead: 20 pounds of H.E. with impact fuse. Range: 120,000 ft at 60,000 ft altitude.

36-inch diameter, 21 per cent thickness-to-chord ratio configuration

Power plant: one integral pancake-shaped solid-fuel rocket motor with 5,000 lbf thrust. Launch weight: 200 pounds. Warhead: 20 pounds of H.E. with impact fuse. Range: 50,000 ft at 60,000 ft altitude.
 

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Speaking of what the I-70 looked like, I'd bet that the nose would be a LOT bigger to accommodate the AN/ASG-18 radar, for starters.
 
Lenticular designs can take severe turns.

The weapon was to be structurally rigid to withstand extremely high launch accelerations, rapid change of thrust direction for quick maneuver, maximum flight duration of 50 seconds, cruising at Mach 6.5+ and terminal velocities of Mach 10.

The expected aerodynamic heating of 3,300 ºF at 11 seconds of flight, requires the use of a leading edge made of Pyrographite. The outer skin of the disc was made of polyester resin, with Titanium B-120 alloy honeycomb core, protected by a layer of Teflon ablating material to restrict skin temperatures to under800ºF. The internal structure was made of magnesium-alloy.
Always wondered how they thought they were going to get that kind of performance out of three little Falcon motors. :confused:
 
Lenticular designs can take severe turns.

The weapon was to be structurally rigid to withstand extremely high launch accelerations, rapid change of thrust direction for quick maneuver, maximum flight duration of 50 seconds, cruising at Mach 6.5+ and terminal velocities of Mach 10.

The expected aerodynamic heating of 3,300 ºF at 11 seconds of flight, requires the use of a leading edge made of Pyrographite. The outer skin of the disc was made of polyester resin, with Titanium B-120 alloy honeycomb core, protected by a layer of Teflon ablating material to restrict skin temperatures to under800ºF. The internal structure was made of magnesium-alloy.
Always wondered how they thought they were going to get that kind of performance out of three little Falcon motors. :confused:
I suppose that these high speeds could only be achieved in forward shots by adding the speed of the Valkyrie to that of the Pye Wacket.
 
Speaking of what the I-70 looked like, I'd bet that the nose would be a LOT bigger to accommodate the AN/ASG-18 radar, for starters.
You have seen just how huge the Valkyrie is, right?

There's a YF-12 Blackbird sitting next to it at the USAF Museum at Wright-Patterson, and you could put the Blackbird under the Valkyrie no troubles.
North_American_XB-70_Valkyrie_at_Wright-Patterson_USAF_Museum_-_June_2016.jpg

Yes, that's a YF-12 nose on the lower left, behind the X-15 tail.

Plenty of space for the ASG-18 radar in that nose, and the monster could probably carry 16 or more AIM-47s in addition to the Pye Wacket missiles, 8 in each bomb bay.
 
Lenticular designs can take severe turns.
In August 1958, the North American project office submitted the proposal Defensive Antimissile System (DAMS) using air-to-air missiles launched by the Valkyrie.

The Defense Feasibility Study was completed in March 1959 and published by the Air Proving Ground Center-Eglin AFB the same month the U-2 incident occurred.

In 1948 the first experimental AAM-A-2 air-to-air missile was launched and entered in service with the USAF in 1955 as the Hughes AIM-4 Falcon.

The original purpose of the Falcon was a Mach 3.8 self-defense weapon for the B-52 bomber and was shortly revived during the B-70 development. The rail-launched missile was not a particularly maneuverable and needed to be pointed in the right direction of the target.

Due to the B-70 speed the Falcon could just be used against any threat coming from its forward hemisphere, but the Valkyrie would have to defend itself against threats from all direction with spherical coverage.

The Falcon was a cylindrical rocket with four delta wings. Would it have been thrown sideways from a B-70 flying to Mach 3 it would have been destroyed by the crosswind shock waves.

North American proposed the Weapons System WS-740A, a wingless lenticular-form rocket with omnidirectional launch capabilities, capable of engaging incoming missiles at relative speeds of Mach 10 and being able to survive and maneuver at 250g accelerations.

The project was awarded to the Convair Division of General Dynamics Corporation, under the codename Pye Wacket in June 1959.

A general aerodynamic evaluation was conducted to determine the technical feasibility of lenticular cross section/circular planform configuration. Wind tunnel tests with several 1/3 scale models were conducted in the Arnold Engineering Development Centre.

The results indicated that the lenticular configuration with blunted trailing edge, sharp leading edge and modified tangent contours, have best aerodynamic characteristics than the symmetrical lenticular cross section, and the most desirable volume distribution for the propulsion system.

The lenticular configuration was efficient at hypersonic velocities with good maneuverability at altitude. Additional tests demonstrated that the aerodynamic controls are not suitable for use in the omnidirectional launch phase of flight, due to the necessity of alignment with the relative wind.

One reaction-jet control system was used, control in yaw, roll and pitch could be obtained by means of the thrust forces generated by four nitrogen-injected binary thrusters, with exhaust through the top and bottom surfaces of the disc.

Pye Wacket had an inertial midcourse guidance system with terminal infrared homing. The Redeye IR seeker was mounted in the leading edge behind an IR window with a look angle of 40 degrees and cooling system.

The USAF determined that internal carriage of eight wingless missiles could be installed in the Valkyrie with no range penalty.

The weapon was to be structurally rigid to withstand extremely high launch accelerations, rapid change of thrust direction for quick maneuver, maximum flight duration of 50 seconds, cruising at Mach 6.5+ and terminal velocities of Mach 10.

The expected aerodynamic heating of 3,300 ºF at 11 seconds of flight, requires the use of a leading edge made of Pyrographite. The outer skin of the disc was made of polyester resin, with Titanium B-120 alloy honeycomb core, protected by a layer of Teflon ablating material to restrict skin temperatures to under800ºF. The internal structure was made of magnesium-alloy.

Three Pye Wacket configurations were proposed in 1961:

60-inch diameter, 21 per cent thickness-to-chord ratio configuration

Power plant: three Thiokol M58A2 solid-fuel rocket motors with 10,200 lbf thrust each. Launch weight: 830 pounds. Warhead: one W54 nuclear device with 50 pounds weight. Range: 100,000 ft at 60,000 ft altitude.

60-inch diameter, 14 per cent thickness-to-chord ratio configuration

Power plant: one integral pancake-shaped solid-fuel rocket motor with 9,700 lbf thrust. Launch weight: 581 pounds. Warhead: 20 pounds of H.E. with impact fuse. Range: 120,000 ft at 60,000 ft altitude.

36-inch diameter, 21 per cent thickness-to-chord ratio configuration

Power plant: one integral pancake-shaped solid-fuel rocket motor with 5,000 lbf thrust. Launch weight: 200 pounds. Warhead: 20 pounds of H.E. with impact fuse. Range: 50,000 ft at 60,000 ft altitude.
I’d like to know more about the Falcon’s potential use by the B-52.
 
Three Pye Wacket configurations were proposed in 1961:


60-inch diameter, 21 per cent thickness-to-chord ratio configuration

Power plant: three Thiokol M58A2 solid-fuel rocket motors with 10,200 lbf thrust each. Launch weight: 830 pounds. Warhead: one W54 nuclear device with 50 pounds weight. Range: 100,000 ft at 60,000 ft altitude.
100,000ft is 19 miles. If you could launch the defensive missile at double that range and have it track, so that the nuke goes off 19 miles away from you, it might not destroy you as well. But if you can't launch until the incoming is 19 miles away, well...

Those two designs with a 20lb HE warhead I'm not sure about... They'd need to hit their target directly.


Always wondered how they thought they were going to get that kind of performance out of three little Falcon motors. :confused:
30,600lb thrust on an 830lb object should be pretty obscene in terms of speed.
 
Speaking of what the I-70 looked like, I'd bet that the nose would be a LOT bigger to accommodate the AN/ASG-18 radar, for starters.
You have seen just how huge the Valkyrie is, right?

There's a YF-12 Blackbird sitting next to it at the USAF Museum at Wright-Patterson, and you could put the Blackbird under the Valkyrie no troubles.
North_American_XB-70_Valkyrie_at_Wright-Patterson_USAF_Museum_-_June_2016.jpg

Yes, that's a YF-12 nose on the lower left, behind the X-15 tail.

Plenty of space for the ASG-18 radar in that nose, and the monster could probably carry 16 or more AIM-47s in addition to the Pye Wacket missiles, 8 in each bomb bay.
Thanks for letting me know!
 

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