An old military doppler radar unit

A little diversion for the festive season for anyone interested in old military electronics.

Earlier this year I visited the Newark Air Museum just outside Newark-on-Trent in the UK. It has an excellent collection of planes, with the jewel in the crown being an Avro Vulcan. On some days, it is possible to do a cockpit tour, and as a result of that I later decided to buy an Air Indicator Unit (AIU) from a surplus supplier.

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I had no idea it was still possible to obtain equipment like that, as the last RAF Vulcan was scrapped in the mid-eighties. The Vulcan was the UK's Cold War nuclear bomber with a quite remarkable specification for an aircraft designed in the late 40s to early 50s. It could fly at over

600 mph, and sometimes exceeded Mach 1 in a dive. Its range was around 4000 miles, with a ceiling of 55 - 65,000 feet.

What initially surprised me was the weight of the AIU - around 10kg (22lb). No wonder the aircraft weighed not far short of 100 tons! When I opened the bottom of the unit the first things I saw were what appeared to be two sealed-unit transformers (although one wasn't a transformer, just a choke). The other was a standard 200v 400Hz transformer, and I wondered why that supply was needed. In my ignorance I expected to find transistors in the AIU, but all I could see at a quick glance was a valve (just over the capacitor above the choke)!

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When I took the top cover off I was even more amazed - the whole unit was full of valves! These were all CV types (some subminiature) - CV465,

468, 469, and 4501.
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I had a look at a few capacitors to see if there was a date on them, but unfortunately there wasn't. There were some rectifiers (such as CV2384 and CV7030), but as far as I could see those were the only semiconductors. The data sheets for CV numbers can be found at

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There were no PCBs of course, just paxolin boards. This is the underside of the valve board:

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On the internet, I found that the AIU was part of a "Green Satin" Doppler radar unit, which provided the navigator with true groundspeed and drift. Anyone interested should search on "Green Satin" and "radar" for more info.

It seems surprising that electronic equipment in an aircraft still flying in the 80s used valves instead of transistors, despite the equipment being constantly upgraded and improved. Maybe the valve-based equipment was considered less likely to be affected by an EMP from a nuclear explosion. But the equipment was reliable - the last Vulcan flew only a year ago in an air display. Maybe because the equipment was of such old design it was that reliable - I was told by the pilot on my cockpit tour that aircrew from the WWII Avro Lancaster bomber would have found much of the Vulcan cockpit instrumentation familiar!

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Jeff
Reply to
Jeff Layman
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hardened against EMP.

The plane was after-all expected to fly reasonably close to atomic bomb explosions.

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This email has not been checked by half-arsed antivirus software
Reply to
Jasen Betts

There were a couple of others, the Valiant and the Victor. The Valiant had structural problems, but the Victors were converted into tankers.

But the Vulcan was indeed a remarkable aircraft.

Even at airshows where the last Vulcan was doing its last display a couple of years ago, I've watched it do things a heavy bomber "really shouldn't be able to do", such as standing on a wing tip and very nearly going vertical. And I /very/ much doubt that was stressing its capabilities!

Very flexible, and a surprisingly low radar cross-section, since everything was buried in the nicely rounded wing.

One still thunders down a runway and lifts its nosewheel, but if the other wheels leave the ground then there will be "An Investigation".

Reply to
Tom Gardner

I saw one of those take off from Goose Bay, Labrador in 1960-something, going near vertical in a blinding snowstorm...impressive indeed.

Reply to
Bill Martin

I was driving along a road and heard a roar from an airfield about 10km off to the side. I glanced in that direction and saw the /full/ delta shape.

A relative tells of the time a Vulcan was coming into land at Bristol Filton when they found out (?how?) that the undercarriage was not properly down and the Vulcan was told, with some urgency(!), not to land. It put on full reheat and disappeared upwards, pronto.

If you realise that a major road (the A38) is just beyond the end of the runway, you will be less surprised to hear that cyclists, cars, and even a bus were blown away!

It landed on foam, at another airport.

Reply to
Tom Gardner

The only time Vulcans saw action was during the Falkland war in 1982. Several refuellings were needed nd they even had to refuel the tankers When the MIG-25 defected to Japan in 1976, :-)

If it works, why fix it ?

When the MIG-25 defected to Japan in 1976, there were jokes about the number of tubes in MIG-25, but later on, the theory was that it was for protection against NEMP.

Perhaps this slowed down any upgrades to the Vulcan and after all, it was going to be retired in a few years.

Reply to
upsidedown

If the jooks had gone down with the Soviet Union during the Cold War, though, I'm not optimistic about how many of them would've actually been able to make it to their targets within Russia.

Even at 600 mph - looks like some serious SAM-bait.

Reply to
bitrex

We'll never know, fortunately.

In the 50s they were high altitude, but in the mid 60s they switched to low-altitude bombing. ISTR that the crews were never convinced that their "toss bombing" would give them sufficient distance between the nuclear detonation and the aircraft. But they probably didn't care; they tended to presume there would have been little point returning to the UK.

They had a low radar cross section, and have been know to evade the USAF's finest interceptors during exercises.

Even so, it is questionable whether they would have been able to penetrate the Soviet Union as effectively as Matthias Rust :)

Reply to
Tom Gardner

I started working at Raytheon in the early 70's while I was still in college. I was amazed to see air-air missiles with tubes inside! Early eighties, they were still selling them to a mid-east country.

Reply to
sdy

I've got a handful of submini tubes (including a crate of 5702's). They're dated late 70s to early 80s. Raytheon and Sylvania. Some are recent ex-Navy stock, so they're not completely out of date yet. (The weapons systems they go into, are, but that's another matter...)

Tim

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Reply to
Tim Williams

I heard that the petrol pumps at a garage were also uprooted and there was a long scorch mark across the field beyond the runway.

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~ Adrian Tuddenham ~ 
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Reply to
Adrian Tuddenham

I /thought/ my relative said a petrol station was set on fire, but as I wasn't sure, I didn't mention it!

Using that extra info and a little bit of noodling around on this newfangled intertubes thingy leads to

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It appears my version was slightly mangled. The aircraft landed but was going to slide off the end of the runway, so aborted the landing. The undercarriage was damaged as it hit the petrol station on the way out. That's more believable than the version I (mis)heard.

Reply to
Tom Gardner

You have to check out what Tatjana van vark has in her dining room! The complete electronics suite form a V-series bomber. I don't know if it all works, but knowing here, it is likely all connected up and operational.

See

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Jon

Reply to
Jon Elson

Thanks for the link. A most interesting project. But the AIU ("Indicator electrical Type 101" - see first link in my OP) is not there. It is also not in the list of equipment at

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- not even the "Not visible units". I photographed it in the Vulcan cockpit I visited, and it can be seen in other Vulcan navigation area pictures on the internet.

I don't doubt that it /might/ be possible to get it all operational but what a Doppler radar unit might show under those stationary circumstances I really don't know!

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Jeff
Reply to
Jeff Layman

Not really. They weren't passive targets as they had quite a bit of ECM fitted. Early Russian SAMs barely had the range and ceiling to hit a Vulcan.

But they would eventually have had, and that is why Blue Steel was developed:

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Jeff
Reply to
Jeff Layman

The S-125 was in service by 1965; it had a service ceiling of 60k feet and could do Mach 3. The upgraded radars in use by the early 1970s put out nearly half a million watts, so good luck on the ECM front (with the tech available at the time.)

Even the export models used by Egypt during the Yom Kippur war shot down several Israeli fighters, and IIRC all the hits on US aircraft by Iraqi SAMs during the 1991 Gulf War were from this type.

Only solution for a Vulcan crew in the early 1970s would've been to fly extremely low to avoid radar for much of the trip, but I think the fuel consumption down there would've meant that there was little way to make it anywhere interesting after the mission was over.

Even with in-flight refueling the "lower" attack profile for the much larger XB-70 launched from Maine, then nearly 1000 miles into the Soviet Union at low altitude and landing in Turkey looks pretty optimistic. I'm not sure what would've been going on at high altitude over the Scandinavian countries during such a situation but probably not anything nice.

The AGM-69 was the US's "solution" for the B-52:

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Reply to
bitrex

More to the point was that the crews tended to believe there was nowhere worth going afterwards. The unsinkable aircraft carrier would have been toasted.

Reply to
Tom Gardner

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Reply to
bitrex

Yes, but the original Vulcan was in service from 1956, and the much improved B2 version (with ECM) from 1960.

The U2 shot down by an SA-2 in 1960 was flying at 70,000 feet - higher than the Vulcan's ceiling, but what, if any ECMs it was using I haven't been able to find.

How reliable the Vulcan's ECM equipment was is another matter:

(the whole thread is quite amusing if you have the time to read it - for example see #25...)

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Jeff
Reply to
Jeff Layman

Here's another of his films with about as much relevance

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bloggs.fredbloggs.fred

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