I know, it's a bit odd... but Air Launched Sea Dart Concept?

Sauragnmon · February 18, 2013, 02:09:24 PM

I know it was toyed around with at one point, and somebody made a model or proposed the way to make a model for an air-launched Sea Dart. I was going to build one, but I forget how the design went - I knew it involved something like the nose of a Sparrow in the opened nose of another missile, but the question is Which one?

Input appreciated greatly.

pyro-manic · February 18, 2013, 02:33:00 PM

Depends - the air-launched Sea Dart would have had a fairing over the nose to reduce drag, so a version being carried would have a smooth nose rather than the ramjet intake of the missile in-flight. You could try using an AIM-54 Phoenix as a basis for building one, though the Sea Dart is slightly larger. Also be aware that the air-launched CF.299 had different control surfaces, with much larger wings and different fins.

Captain Canada · February 18, 2013, 05:40:09 PM

It would be interesting to know what missiles you ( or they ) were going to use as a basis, as the Sea Dart is for sure one of the coolest looking missiles out there ! Also, you'd think it wouls have been easy to engineer a way to open the ramjet intake as the missile was launcehd, either with a trap door or a nose cone that could retract ?

rickshaw · February 18, 2013, 07:20:49 PM

IIRC there are Sea Darts available in 1/72 from Fleetscale, one of the naval model making firms - http://store.fleetscale.com/index.php?_a=product&product_id=533

Captain Canada · February 18, 2013, 07:36:37 PM

Woah....great link ! Now I just need to rob a bank ! I'd absolutely love to detail out a 72nd scale RC Leander !

Sauragnmon · February 18, 2013, 09:26:08 PM

Damn, Rickshaw, that's some cool stuff right there. I never heard about them. Well, I guess that just goes one step further than I was thinking. I'll have to keep that in store and get some of those for that build I have in the back of my head...

Go4fun · February 18, 2013, 10:39:03 PM

Quote from: Captain Canada on February 18, 2013, 05:40:09 PM
It would be interesting to know what missiles you ( or they ) were going to use as a basis, as the Sea Dart is for sure one of the coolest looking missiles out there ! Also, you'd think it wouls have been easy to engineer a way to open the ramjet intake as the missile was launcehd, either with a trap door or a nose cone that could retract ?

How about a 'Sabot' type nose cone that peels away in pieces as it reaches speed?

PR19_Kit · February 19, 2013, 12:34:51 AM

The outboard jets on the later model B-36s had folding petals inside the intakes so they could be blanked off when out of use. Would such a scheme work for a Sea Dart?

pyro-manic · February 19, 2013, 03:56:23 AM

I suppose you could, but you'd still end up with a very draggy shape, due to the shape of the ramjet intake. I suspect the drag from those B-36 pods would have been horrific at high speed too. Chugging along at 350mph they were probably fine, but at Mach 1, not so good!

Sea Dart nose:

Weaver · February 19, 2013, 04:22:11 AM

I've always thought the way to do it was to make the centre-cone retract.

BTW, one of the reasons that air-launched Sea Dart was never adopted was that the four-aerial interferometer homing head mandated by the nose intake was much less sensitive than a dish-type, so it needed a whacking great illumination radar to compensate. This is not too much of an issue on a ship (although compare the size of a Type 909 to the various Standard illuminators), but it's a killer for an aircraft unless you can fit a seriously large radome on it.

I came up with a scheme for Sea-Dart-ish missiles based on hacked up Phoenixes to go under a Sea-Vixen/Tomcat hybrid:

Top is a standard AIM-54.

Middle has the nose cone cut off and re-set inside the body, main wings reversed and control fins cut diagonally. Essentially, this is the "easy" version.

Bottom is the same thing, but with new/re-profiles wings.

Thorvic · February 19, 2013, 04:35:09 AM

The Vulcan ADV shown on the Cover of Battle Flight had conventional Sea Dart in the Air to Air role, of course the Vulcan was able to carry the the Radar(s) needed to operate the missiles, where most conventional interceptors couldn't.

PR19_Kit · February 19, 2013, 04:49:12 AM

Quote from: pyro-manic on February 19, 2013, 03:56:23 AM
I suppose you could, but you'd still end up with a very draggy shape, due to the shape of the ramjet intake. I suspect the drag from those B-36 pods would have been horrific at high speed too. Chugging along at 350mph they were probably fine, but at Mach 1, not so good!

No no no, I didn't mean adopt the B-36 pod itself!

I meant adopt the IDEA of the folding petals, when retracted they were flush with the intake cone of the jets, no reason why a smaller version wouldn't work on the Dart's ramjet.

In response to Weaver's comment about the lack of radar in the nose of the Dart, why didn't they put a small aerial inside the intake cone itself, or was it just too small to be practical?

pyro-manic · February 19, 2013, 05:15:56 AM

I know that!

I meant that just closing off the intake would itself be very draggy, as you'd end up with an almost flat face due to the shape of the intake and nosecone. The B-36 could get away with this as it was sloooow, but it wouldn't work on a missile that was to be carried at supersonic speeds. You'd have to completely redesign the front of the missile.

Weaver · February 19, 2013, 09:35:00 AM

Quote from: PR19_Kit on February 19, 2013, 04:49:12 AM
In response to Weaver's comment about the lack of radar in the nose of the Dart, why didn't they put a small aerial inside the intake cone itself, or was it just too small to be practical?

Too small for 1960s tech. An AMRAAM seeker would fit a treat though.....

My old idea was to fit a staring (i.e. non-moving) transmitter in the centre cone, with a flatter-than-usual dish so that it's produced a wide fan beam, and then have the echoes from that picked up by interferometer aerials that were moved backwards and outwards into the tips of fixed nose "fins" so that they were shielded from the outgoing signal. The missile would then be semi-active during most of it's flight but fully active (and hence autonomous) in the last stage. However, this was all before I was aware of the relative insensitivity of the interferometry technique, and I suspect that would stop it from working, since it would probably need a more powerful transmitter than could be fitted in the centre cone to work at any useful range.

Sauragnmon · February 19, 2013, 10:01:48 AM

There's that image... it was YOU that did it, Weaver. I knew it was all about cutting the nose and putting another seeker head in... I was trying to remember if it was a STARM or a Phoenix, I knew it was a Strakes-and-tail missile that was converted. You were talking about a Sparrow head in the nose of the Phoenix, I remember it now.

I wonder how big the dome is, compared beside a Sparrow... I remember the Sea Dart was limited more by the missile's own range than the radar or the seeker head - the Radar could illuminate a target up to 90NM, but the Dart couldn't get that far. I wonder if the SARH head off a Sparrow could fit in the Dart's nose..

I wasn't going for a perfect Sea Dart copy, but the ramjet nose was sure as hell appealing to me. The thought of an AIM-120 seeker in a Sea Dart sure is appealing though. Not a whole hell of a lot of time to adjust when it's flying at Mach 3-4 with that ramjet engine.

Another idea - what if there wasn't a tail-mounted booster like the Naval version, so airflow was unimpeded through the flow channel of the ramjet? It wouldn't need a Standing Jump boost, so you could put a semi-conformal booster to give it that extra kick, assuming it needs one, being launched from a moving aircraft.