Sparrow II active radar homing missile

[overscan (PaulMM)]

Length: 148"
Diameter: 8"
Wingspan: 40.128"
Tailspan:32"
Weight: 420lb (warhead: 72lb inc fuse (49lb warhead), seeker 47kg)
Seeker: Bendix AN/DPN-21 active radar seeker
Range: 6nm
Velocity: 3000ft/sec
Altitude: 100-60000ft

Source:
C.M. Hanson: "Characteristics of Strategic, Tactical and Research Missiles", Convair San Diego, 1954/58

http://handle.dtic.mil/100.2/AD388603

 

[Archibald]

Wasn't this missile studied for the F-5D Skylancer, then took over by the Canadians for their CF-105 Arrow ? How far did the whole program go ?

 

[Trident]

A comparison of the internal layout with modern ARH missiles is quite telling - the seeker on this very early design is so large that the warhead is located behind the wings and the rocket motor is very short too.

 

[Mark Nankivil]

Greetings All -

Here's a photo of an F4D Skyray carrying a Sparrow II. For some reason, the original photo title refers to the missile as a Nike.

Enjoy the Day! Mark

 

[Rickshaw]

A comparison of the internal layout with modern ARH missiles is quite telling - the seeker on this very early design is so large that the warhead is located behind the wings and the rocket motor is very short too.

Most air-to-air missiles have their warheads amidships.

 

[gtg947h]

A comparison of the internal layout with modern ARH missiles is quite telling - the seeker on this very early design is so large that the warhead is located behind the wings and the rocket motor is very short too.

Most air-to-air missiles have their warheads amidships.

Yes, but not that far aft... AIM-120, for example, has a much shorter electronic section (proportional to total length), so the warhead is further forward and the motor is longer. So same layout, but different proportions because the early electronics were much bulkier.

 

[SOC]

Wasn't this missile studied for the F-5D Skylancer, then took over by the Canadians for their CF-105 Arrow ? How far did the whole program go ?

Sparrow II was considered for the Arrow and was trialled on a CF-100. Ultimately the Arrow was to have used 8 Hughes GAR-1 Falcon AAMs, Sparrow II was investigated briefly as a better option. USN killed Sparrow II in 1956, the RCAF dropped it in 1958. Both sides basically killed it due to the problems of making a fully active radar guided AAM in the 1950s.

 

[Archibald]

Seems that Canadair got the contract.

I quick search show that the Skylancer had an APQ-64 radar. The Sparrow II was k-band.
Main problems found were
- K-band at the time couldn't see through clouds and rain (pretty annoying)
- active homing on the AMRAAM is only for the final dash on the target, this wasn't known in Sparrow II days
- both APQ-64 and the missile K-band seeker were very limited in performance by 50's electronics, vacuum tubes included.
- range was a miserable 5 nautic miles !

Since the Arrow radar was called ASTRA, I wonder if it was a copy of the APQ-64. What is interesting is that the Arrow nosecone should have been much larger than the Skylancer, considering these aircraft respective sizes... maybe they hoped to boost k-band efficiency through a larger size.
Considering the difficulties encountered by the Sparrow II, it is no surprise it doomed the program. The RCAF evidently fell to the deadly lure of "fire and forget, AMRAAM in the 50's". Truth is, it was exciting, imagine, if they had made it to work, the tactical advantage the Arrow would have had shooting bombers.

Considering the miserable range plus all the seeker issues, Sparrow III was the right choice even with SARH. Considering its pathetic reliability rate in Vietnam, imagine Sparrow II in the same context... better to arm Phantoms with RPG-7s !

 

[Forest Green]

Length: 148"
Diameter: 8"
Wingspan: 40.128"
Tailspan:32"
Weight: 420lb (warhead: 72lb inc fuse (49lb warhead), seeker 47kg)
Seeker: Bendix AN/DPN-21 active radar seeker
Range: 6nm
Velocity: 3000ft/sec
Altitude: 100-60000ft

Source:
C.M. Hanson: "Characteristics of Strategic, Tactical and Research Missiles", Convair San Diego, 1954/58

http://handle.dtic.mil/100.2/AD388603

Only 6nm, or 60nm?

 

[TomS]

Only 6nm, or 60nm?

From the cited doc 6nm is right, and I can't imagine why it would be much more. AIM-7C was publicly credited with about 6-7nm, and I don't think any version of AIM-7 ever reached 60nm, even with the much better seekers and dual-stage motors in the final models. The usual number cited for AIM-7F/M/P is 43nm.

 

[Archibald]

plus if the freakkin' K-band seeker couldn't see through rain or clouds... the missile range will be pretty short...

 

[overscan (PaulMM)]

Sparrow II and III comparison from 1957.

 

[pathology_doc]

Considering its pathetic reliability rate in Vietnam, imagine Sparrow II in the same context...

Sparrow faced numerous problems in Vietnam, not least of which is that it was being asked to do something it had never been designed for, because of political constraints. In addition, the repeated launch-dogfight-land sequence for those missiles which were brought back at the end of a mission was also unanticipated, leading to further reliability issues until maintenance was properly addressed. The climate was also not all that friendly to it.

As a missile fired by an air defence interceptor launched from a base in a temperate climate, with relatively relaxed ROE against a bomber-sized target that doesn't share the manoeuvrability of a MiG-17, I think it would be expected to do significantly better.

Radar missiles doing fire and forget off the rack was the siren song that also doomed Red Dean. The difference is that the British didn't have the parallel compromise solution that the SARH versions of AIM-4 represented, and all of Britain's radar-guided air-to-air missile work went down the drain with the loss of indigenous supersonic fighter development, not to be seen again until after the British had accepted Sparrow and developed Skyflash as an outgrowth of it.

What happened in the British radar AAM field in between Red Dean being axed and Skyflash being bought would make for some very interesting reading.

 

[Archibald]

I compiled a brief Sparrow II timeline covering the years 1950 to 1959

A brief Sparrow II timeline

1950-51 Oriole canned, Douglas steps in and propose to repackage the ARH seeker into a Sparrow 1 airframe.

1952 - first firing from F3D Skynights, later replaced by 5 F4D Skyrays.

1954 - August - success against multiple targets

1955
F4D-1s 134-754/-762/-763/and -765 enter rework and modification at EI segundo between mid-May and mid-December 1955, being completed between mid-January and late April 1956. 134 -748 was modified between late April and early September 1956.

- December - Canada decides to buy 900 missiles, not only for the Arrow, but also for 4 CF-100 squadrons
(mark 5M, 6, 7 thin wing afterburner variants)

1956
- Late june, RCA screws Hughes and gets the Astra-1 contract for the CF-105.
- F5D Skylancer tops at 19 aircraft in July then is gradually canned in steps starting in October.

- The five F4D Skyrays are send to Point Mugu and outfitted with the complete system
- APQ-64 radar
- Aero 13A FCS
- live Sparrow II missiles

1957
March Skylancer finally canned to only 4 prototypes build. Send to NACA in August.
April-June the five Sparrow II Skyrays at Point Mugu are send elsewhere, too (not NASA)

1958
April.
Canadair is given the Sparrow II airframe contract. They build only two missiles with Bendix and douglas inputs.
Canadian Westinghouse gets the seeker.
RCAF "Ultra West" detachment of CF-100s to Point Mugu is created.

August-September
Ultra West CF-100 start Sparrow II trials

September 23: Astra, Sparrow II (and tacitally, the Arrow itself) are all canned.

Note 1
Westinghouse APQ-50, APQ-64 and APQ-72 are close siblings.

APQ-50: Skyray, 24 inch antenna.
APQ-64: Skylancer, same with Sparrow II
APQ-72: Phantom, 32-inch enlarged antenna, Sparrow III SARH

 

[zen]

Considering its pathetic reliability rate in Vietnam, imagine Sparrow II in the same context...

Sparrow faced numerous problems in Vietnam, not least of which is that it was being asked to do something it had never been designed for, because of political constraints. In addition, the repeated launch-dogfight-land sequence for those missiles which were brought back at the end of a mission was also unanticipated, leading to further reliability issues until maintenance was properly addressed. The climate was also not all that friendly to it.

As a missile fired by an air defence interceptor launched from a base in a temperate climate, with relatively relaxed ROE against a bomber-sized target that doesn't share the manoeuvrability of a MiG-17, I think it would be expected to do significantly better.

Radar missiles doing fire and forget off the rack was the siren song that also doomed Red Dean. The difference is that the British didn't have the parallel compromise solution that the SARH versions of AIM-4 represented, and all of Britain's radar-guided missile work went down the drain with the loss of indigenous supersonic fighter development, not to be seen again until after the British had accepted Sparrow and developed Skyflash as an outgrowth of it.

What happened in the British radar AAM field in between Red Dean being axed and Skyflash being bought would make for some very interesting reading.

We have a series of paths that seem to emerge.

Firstly the monopulse seeker concept, likely for Red Hebe.
Secondly the twin dish ABM missile seeker. I think FMCW.
Thirdly a 9" dish seeker for late NIGS, is suspiciously close to Red Top diameter.
Fourthly the FMICW system. The latter led to actual hardware tested on a Canberra. This formed the basis of the John Forbat AAM design.

And then the polyrod Sea Dart seeker.

Oh and at least two SARH seeker concepts for Red Top from the early 60’s.

 

[Zoo Tycoon]

The polyrod seeker needs a lot of reflective signal to get directional discrimination. A strong illumination output worked well in an aggressive jamming environment but producing such would rapidly exceed the electrical power available in most smaller fighter ..... no problem for a warship or a flying Battle ship such as the Vulcan.

 

[Hood]

Tony Wilson's English Electric Lightning: Genesis & Projects mentions that in May 1956 the MoS were considering arming the Saro P.177 with Sparrow II to overcome Blue Jay's poor weather limitations and were asking Ferranti if they could add CW injection into the AI.23.

 

[overscan (PaulMM)]

Crossposted reply:

From my P.1121 book -

Drawings of P.1103 with American Sparrow
weapons were produced in 1955. The
Hawker drawings seem to show how the general
shape of the AAM-N-2 Sparrow I, but the
intended model appears to have been the
AAM-N-3 Sparrow II, while Ralph Hooper’s
notes seem to have mixed up Sparrow II and
Sparrow III in terms of which version had
active radar homing.

The Sparrow II doesn't need a CW illuminator as it has its own radar, so it seems likely that they were actually intending to fit Sparrow III with SARH homing. AI 23 with CW illuminator added crops up in various programs in this timeframe.

It seems that there was a lot of confusion about Sparrow versions at the time, as Ralph Hooper's notes on Sparrow definitely have II and III the wrong way around.

 

[pathology_doc]

We have a series of paths that seem to emerge.

I know, but the simple fact is that in 1956, British industry couldn't make a radar-guided AAM to save itself. Something happened at the R&D level to make the Skyflash seeker head possible, despite the British not turning out a single prototype SARH AAM even on a captive-carriage level in the interim.

 

[zen]

But that's not true seekers were flown on Canberras. I suspect the A4 (or us it A5 I am away from my books) seeker is the ancestor to Skyflash.
A lot of R&D was ongoing and seekers flown, but the projected missiles all got cancelled, put back or revised to different roles repeatedly until death.
Skyflash was virtually a last ditch and welcome relief to have a missile to fit UK technologies into, that might actually get to testing as a complete system.

 

[yellowaster]

We have a series of paths that seem to emerge.

I know, but the simple fact is that in 1956, British industry couldn't make a radar-guided AAM to save itself. Something happened at the R&D level to make the Skyflash seeker head possible, despite the British not turning out a single prototype SARH AAM even on a captive-carriage level in the interim.

From what I've read, there were a series of research studies and trials on air-to-air and surface-to-air guidance heads in the UK during the 1960s (including, as zen notes, the GEC A5). Those, plus input from projects like Sea Dart, fed into the Saleable Homing Head project (~3 years, contractor GEC/MSDS, technical authority RRE) in late 1960s - a modular SARH head suitable for AAM or SAM using CW or PD guidance. Designed to be suitable for a new GW or as a retro-fit head to an existing weapon. Later renamed the Microelectronic Homing Head and selected for Skyflash.

 

[Hood]

Having a decent radar able to integrate a radar-guided AAM with seems to have been the biggest problem.

 

[zen]

Having a decent radar able to integrate a radar-guided AAM with seems to have been the biggest problem.

They had first AI.18 developed and we know lookndown capability was tested.
We know a FMCW set was built and even flown. Results not so good in the air so they moved over to FMICW instead and this did perform.

Anyway apologies for thread hijacking.

 

[NMaude]

What happened to the Active Skyflash project?

 

[zen]

What happened to the Active Skyflash project?

Didn't the seeker end up in Meteor?

 

[NMaude]

What happened to the Active Skyflash project?

Didn't the seeker end up in Meteor?

I checked at the wiki article on the Meteor and according to it the seeker is based on the AD4A seeker family used in the MICA and Aster missiles.

Edit: I checked the Skyflash article and apparently the S225XR did form the basis for the Meteor AAM.

 

[pathology_doc]

But that's not true seekers were flown on Canberras. I suspect the A4 (or us it A5 I am away from my books) seeker is the ancestor to Skyflash.
A lot of R&D was ongoing and seekers flown, but the projected missiles all got cancelled, put back or revised to different roles repeatedly until death.
Skyflash was virtually a last ditch and welcome relief to have a missile to fit UK technologies into, that might actually get to testing as a complete system.

Thanks for that reply. BSP4 is very thin on this ground, and while there's a lot of talk (e.g. Forbat's missile, the DeHavilland/Hawker Heavy family), most of it never seemed to get beyond paper. I'll hit the knees and pray for all this to be revealed in due course, once the relevant time-frames on the Official Secrets Act have elapsed.

 

[zen]

But that's not true seekers were flown on Canberras. I suspect the A4 (or us it A5 I am away from my books) seeker is the ancestor to Skyflash.
A lot of R&D was ongoing and seekers flown, but the projected missiles all got cancelled, put back or revised to different roles repeatedly until death.
Skyflash was virtually a last ditch and welcome relief to have a missile to fit UK technologies into, that might actually get to testing as a complete system.

Thanks for that reply. BSP4 is very thin on this ground, and while there's a lot of talk (e.g. Forbat's missile, the DeHavilland/Hawker Heavy family), most of it never seemed to get beyond paper. I'll hit the knees and pray for all this to be revealed in due course, once the relevant time-frames on the Official Secrets Act have elapsed.

Black Box Canberras....a good read I recommend it.

 

[pathology_doc]

But that's not true seekers were flown on Canberras. I suspect the A4 (or us it A5 I am away from my books) seeker is the ancestor to Skyflash.
A lot of R&D was ongoing and seekers flown, but the projected missiles all got cancelled, put back or revised to different roles repeatedly until death.
Skyflash was virtually a last ditch and welcome relief to have a missile to fit UK technologies into, that might actually get to testing as a complete system.

Thanks for that reply. BSP4 is very thin on this ground, and while there's a lot of talk (e.g. Forbat's missile, the DeHavilland/Hawker Heavy family), most of it never seemed to get beyond paper. I'll hit the knees and pray for all this to be revealed in due course, once the relevant time-frames on the Official Secrets Act have elapsed.

Black Box Canberras....a good read I recommend it.

D'oh! I think I've actually GOT that book. Will go back and re-read.

 

[NMaude]

I wonder if Douglas came back in 1960 and revisited the Sparrow II design and used what was state-of-the-art in 1960 electronics if they could've succeeded or alternatively trying again 1965 and using what was state-of-the-art in 1965?

 

[Archibald]

This amounts to inventing AMRAAM earlier, and I'm not sure the state of the art would allow it. AMRAAM development itself in the 1980's was aparently no bed of roses.
Even the huge YF-12 missiles were still SARH, like a Sparrow III.

 

[Archibald]

And shame on me, can't remember whether the AIM-54 Phoenix was active or semi-active radar homing. EDIT: was active homing, at least partially.
I think it was the best that could be done with 1960-70 technology. Earlier on were the APQ-81 & Bendix Eagle, yet they never left the drawing board.
Both Phoenix and Eagle missiles were huuuuge.

 

[NMaude]

This amounts to inventing AMRAAM earlier, and I'm not sure the state of the art would allow it.

Suspect it would with the technology advances in electronics during the 60s (Perhaps even with what was state of the art in 1960) however the resulting missile would likely have a much smaller range than the AMRAAM.

 

[pathology_doc]

Suspect it would with the technology advances in electronics during the 60s

Considering that this is the decade in which Phoenix begins its gestation, most likely yes. Again, you're probably looking at sacrificing some range for this for various reasons.

 

[Archibald]

I wonder - how small could one shrink a Phoenix by cutting its range to say, 10 miles ?

An AMRAAM in the 1960-70 could start as a mini-Phoenix, but how small could it go ?

 

[TomS]

Suspect it would with the technology advances in electronics during the 60s

Considering that this is the decade in which Phoenix begins its gestation, most likely yes. Again, you're probably looking at sacrificing some range for this for various reasons.

I wonder - how small could one shrink a Phoenix by cutting its range to say, 10 miles ?

An AMRAAM in the 1960-70 could start as a mini-Phoenix, but how small could it go ?

I'm not at all convinced that they could shoehorn a viable active seeker into an 8-inch diameter missile even in 1965.

 

[pathology_doc]

Suspect it would with the technology advances in electronics during the 60s

Considering that this is the decade in which Phoenix begins its gestation, most likely yes. Again, you're probably looking at sacrificing some range for this for various reasons.

I wonder - how small could one shrink a Phoenix by cutting its range to say, 10 miles ?

An AMRAAM in the 1960-70 could start as a mini-Phoenix, but how small could it go ?

I'm not at all convinced that they could shoehorn a viable active seeker into an 8-inch diameter missile even in 1965.

They would have had a much better chance than they did ten years earlier, that's for sure. Ultimately it depends on what performance envelope you're willing to accept for your missile. Sparrow is a medium range BVR missile by design intent, but saw a lot of highly unintended dogfight use at ranges which would probably be well within the capability of an eight-inch dish to allow fire-and-forget, and still have a sufficiently long burn on the motor (if that has to shrink to preserve warhead size within a given missile volume) to take you there.

Granted, midcourse management and handover to the missile's seeker isn't going to be a thing unless the fighter's systems are designed for it (AWG-9 or similar), but the ability to select between SARH for long-range shots and ARH for dogfights shouldn't be hard to arrange.

 

[Heatloss]

Considering the miserable range plus all the seeker issues, Sparrow III was the right choice even with SARH. Considering its pathetic reliability rate in Vietnam, imagine Sparrow II in the same context... better to arm Phantoms with RPG-7s !

The reliability issues were mostly down to carrier ops and mechanics who couldn't care less. The landing and arresting were very hard on the 7E, and the AF had some pretty incompetent ground crew, who didn't treat them well. Even then, reliability was mostly not the issue.

The biggest issue is that most AIM-7s were fired WITHOUT a system track. The time between a lock and a full system track firing on all but the late F-4Js was four seconds. The FCS took about two seconds or so to settle on the track and provide accurate speedgate information to the missile, which would then take another two seconds or so to properly tune the missile speedgate to the expected velocity sweep range provided by the launching radar.
Most were instead fired with the radar caged to the boresight, the CW active, and with wide speedgate selected, which would sweep the speedgate through the whole AIM-7E's velocity range. You were almost turning the 7E into a beam-rider. And it could fail to acquire the target due to the wide speedgate sweep not picking your target up for whatever reason.

I believe that the Sparrow II, while worse for the initial purpose, would have found an odd success if it had served in Vietnam. Cost, though, would have been prohibitive.
(Sorry for the many edits, it's late and I'm tired. Lots of grammar and readability edits.)

 

[Scott Kenny]

I'm not at all convinced that they could shoehorn a viable active seeker into an 8-inch diameter missile even in 1965.

Think they'd be able to make an 8" diameter X-band seeker that early?

A K-band seeker would be more or less worthless.

 

[NMaude]

I suspect that if the AIM-7B's GCU electronics was redesigned to use 1965 electronics tech a workable missile could be available by 1970, late in the Vietnam War having an active radar guided Sparrow with the AIM-7E2 mods (Call it the AIM-7B2 or maybe AIM-7F). Would be handy as a dogfighting AAM especially if it had the Mk-38 rocket-motor instead of the original Aerojet 1.8KS7800 solid rocket motor.