Talk:AN/APS-20

Dubious: Goodyear ZPG-3W and Sikorsky HR2S-1W

It is well documented that the 4 Goodyear ZPG-3W blimps used the specially designed and built AN/APS-70 radar (with a massive 42 ft / 12.8 m internal antenna), so the inclusion of the ZPG-3W in this article is extremely dubious. Also, photos of the ZPG-3W show no sign of the AN/APS-20 radome that is so visible on the underside of the ZPG-2W.

Likewise, it is documented that the 2 HR2S-1W helicopters used the AN/APS-32 radar; this is not as strongly documented, but it is obvious from photos of the helicopter that the radome was much larger than that needed for the AN/APS-20, so again this is a dubious inclusion. Not much is known about the AN/APS-32, perhaps it was a development of the AN/APS-20?

Thank you Tfdavisatsnetnet (talk) 15:29, 13 April 2023 (UTC)

Why are you assuming that radar arrays only come in one size for a radar type? Many radar arrays are sized for the installation. I've found several sources listing the APS-20E as the radar for the HR2S-1W, with the best one being here. I think the Sikorsky Archive is the anomaly, not the others. BilCat (talk) 20:06, 13 April 2023 (UTC)

Well, your "best one" states that the HR2S-1Ws were developed in the 1960s, but the first of these was delivered on 3 June 1957[1] and the program was terminated after the crash of one of the prototypes on 3 December 1958. The Sikorsky Archive site is run by former Sikorsky employees who had access to Sikorsky documents, so I would think they know their subject, and this gives it more weight. Still, I don't doubt that there was literature published in the 1950s that stated the HR2S-1W was designed to use the APS-20E. The later model EC-121 belly radome and HR2S-1W radome are comparable in size (unlike the early EC-121 versions - it's too bad the EC-121 article doesn't zero in on the introduction of the APS-20E, but the AN/APS-20 article says it was 1953, and that date would fit). I've looked for my Sikorsky books; the best one is MIA, and the next does reference the APS-20E. Let's see what the MIA book says, it may take me a week to get it.

But, as as I commented earlier I suspect there is a real possibility that the APS-32 was developed from the APS-20E (and yes, WP bans speculation in articles, but what about Talk pages?). Also, the List of radars § AN/APS series article entry on the APS-32 is very likely wrong: all of the Grumman TBMs were retired from USN service in the mid-1950s, and the -3W even earlier, so it is highly unlikely that the APS-32 (a mid-1950s development) was intended for the TBM-3W as that article states (and it misnames the TBM-3W as well).

I'd vote to leave the dubious flag on the HR2S-1W until hell freezes over, or until we know better what the APS-32 really was. The APS-70 is different: Sky Ships specifically states it was designed for the ZPG-3W, and even includes a cutaway drawing of the huge antenna inside the blimp envelope. It could not have been fitted to any other aircraft. Sky Ships also calls into question the List of radars § AN/APS series article entry on the APS-70. I'd vote to delete the ZPG-3W from any association with the APS-20.

Thanks Tfdavisatsnetnet (talk) 04:09, 14 April 2023 (UTC)

The Polmar error could also by a simple typo, and I've seen plenty of very simple mistakes in the SikorkArchives. It's also possible the APS-32 was an upgrade or redesignation of the APS-20E, or even a different model installed later. BilCat (talk) 04:30, 14 April 2023 (UTC)

"It's also possible the APS-32 was an upgrade or redesignation of the APS-20E"

I think that possibility is very real. Perhaps the APS-32 was the APS-20E with features specifically intended for helicopter operations (i.e. additional vibration dampening). I was too busy to research this in the last few days, and the next 2 don't look good either. But I'll be back. Tfdavisatsnetnet (talk) 22:39, 16 April 2023 (UTC)

Hi. In the Radar picket article I changed 'AN/APS-32' to 'AN/APS-20E or AN/APS-32 radar (sources differ)'. Something like that might be appropriate here and in the List of radars article. Tfdavisatsnetnet (talk) 01:35, 18 April 2023 (UTC)

References