ACLS is the initialism for Automatic Carrier Landing System. For more, see
http://thanlont.blogspot.com/2011/07/look-no-hands.html
Up until now, I'd never seen a good picture of the radar reflector as incorporated on the F-4 Phantom although I'm sure there must be one or more in the F-4 books that I don't have. This was the best I could come up with. There was a door under the nose and a corner reflector extended from the compartment it was housed in.
Thanks to Angelo Romano, we now have one:
It took me a few minutes to figure out how it folded up even with this illustration in hand, which depicts the reflector from behind:
If you look closely at Angelo's picture above, there is a line on the panel on the left (on the right side of the F-4) that shows where it folds in half. It is then sandwiched between the upper panel and the one on the right to form a very compact package that can be stored in the space available.
Hi Tommy, great detail shot. Thanks for making it available.
ReplyDeleteWas this device only fitted to to F-4B's and Navy F-4Gs?
I can't recall ever seeing it on any of the hundreds of F-4J or even N photos I have.
That photo with the Red Shirt in it is an F-4J, you can tell by that small radome with the labeling "Static System Drain" on it. That is the "little bump" on the bottome of an F-4J radome. (or F-4S, it had the same feature on the radome)
DeleteMy guess is that the reflector only extended when the ACLS was selected. I have a few pictures of Phantoms on approach to the carrier with it extended. One is shown in the post.
DeleteIt wasn't used on the F-4B, the F-4G was the conversion to test it and implement it.
ReplyDeleteIt started on the F-4G conversions from F-4B, then was used on the F-4J, later on it was used on F-4N and F-4S. (the first F-4G didn't have a door, the reflector was permanently mounted on that one)
No that's incorrect. Some F-4Bs were modified with ACLS for example VF-14 & VF-32 transitioned to "new" reworked F-4Bs in October 1972 that had been modified with ACLS & Data Link (also ALR-45/50 RHAW/ECM). I have an image of F-4B 152222 AB205 landing aboard JFK in 1973 with the Radar reflector deployed. Can't see a way of posting it here though?
DeletePeter - if you send the photo to me I'll add it to the post with a credit to you. Thanks, T
DeleteHello,
ReplyDeletethree good pictures can be found in Danny Coremans Book: Uncovering the US Navy Q/F-4B/J/N/S Phantom, page 133. But not with the excellent background information provided here :-)
Regards,
Martin
Thanks - I have several F4H books but not that one.
DeleteHi Tommy, I can confirm that the F-4J had one of these fitted and when I get a chance I will try and open mine on ZE350 (153768) and photograph. Currently its in a workshop having some more restoration work done on the radome mounts, so access is a bit tight. I would love to know how it works though, if anyone can update me? Cheers
ReplyDeleteI worked for McDonell Douglas in the '60s in the antenna lab. We tested dozens of these corner reflectors for spec compliance using a laboratory Ka band (33.2 GHz I believe) circularly polarized radar. As shown in the second picture above there is a panel attached to the top third of the reflector. As shown in the third picture this consists of a dielectric core of 0.176 in thick section of EccoFoam sandwiched between two layers of pre-preg fiberglass. Without this panel the reflected circularized radar return would have been the opposite sense and be virtually undetectable. The purpose of this panel is to provide a phase shift to the incident radar signal that reverses the polarization sense so that is matches the radar polarization. The spec compliance failures were almost always due to this panel not performing as required.
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