H Is For..................?

[Jack Cook]

P-51H s/n 44-64182 note the APS-13 Tail Warning Radar

[The Inspector]

HAWULINAZZ

[Mudge]

Is it the little thingy sticking out from the vertical stabilizer? Is there one on each side?

Mudge the visually challenged

[daveymac82c]

Mudge,

I think those are "Cheap Seat Handles."

-David (the maybe not so witty after just waking up)

[Mudge]

Mudge,

I think those are "Cheap Seat Handles."

-David (the maybe not so witty after just waking up)

David...Waking up or wide awake we can't tell the difference.

Mudge the humorist

[retroaviation]

Mudge, that's the radar thingy that Jack was eluding to.

Gary

[Nathan]

haha yeah I was wondering where Jack ment too.

[Mudge]

I'll ask again. Is there one on each side? Seems to me, if there isn't, there'd be a blind spot at about 5 o'clock or can the pilot see 5 o'clock?

Mudge the educable

[Speedy]

...Hrududu.

[spookythecat]

I'll ask again. Is there one on each side? Seems to me, if there isn't, there'd be a blind spot at about 5 o'clock or can the pilot see 5 o'clock?

Mudge the educable

As seen on "Happy Jack's Go Buggy"

As far as I know they were on both sides.

[Taigh Ramey]

Hello Mudge,

Yes, there are two sets of antennas, one on each side of the vertical stabilizer.

The APS-13 would send radio waves through these directional antennas toward the rear. When the radio waves reflected off of something back to the antennas a bell and light went off in the cockpit warning the pilot to check six. The set was adjustable as to when the relay would trip the warning lights and bell.

The APS-13 was used in many WWII aircraft like the P-47 and the P-61.

One of the most interesting uses of this set in WWII was in the atomic bomb program. If you look closely at both of the atomic bombs used at Hiroshima and Nagasaki you will see four of the antennas mounted evenly around both Fat Man and Little Boy. I always wondered about this until I figured out how the APS-13 worked then it dawned on me. The bombs were triggered above the ground for maximum destruction. The APS-13 would do that perfectly. When the radio signal returned at a specified duration the set would trip a relay and set off the bomb.

I later learned that they had four of these sets in the rear cone of the bomb and they were battery powered. They used four APS-13's because the bomb was likely to rotate on its way to the target so one or more of the antennas might be blocked by the bomb case. When two of the APS-13's delivered a trigger signal the bomb was detonated.

The frequencies for the APS-13 were monitored on the flight to be sure that there was no interference or jamming prior to release. In case the APS-13's didn't do their job there was an aneroid triggering device as a back up.

There are two APS-13's installed and working in restorations today, that I know of. The first one was put in Flying Heritage's P-47D by Westpac Restorations and the other, if I recall correctly, is in Happy Jack's Go Buggy restored by Mike. It was my honor to provide the set used in FHC's Thunderbolt. Sorry I wasn't able to get one to you Mike.

I would sure love to hear any veterans stories about the combat or training use of the APS-13.

[Matt Gunsch]

Is it the little thingy sticking out from the vertical stabilizer? Is there one on each side?

Mudge the visually challenged

Mudge,
look here
http://www.duxfordradiosociety.org/rest ... aps13.html

[Holedigger]

...and here I thought they were for picking up the game for those long ferry hops!

Are those operational on Jack's Go Buggy or just for show? How often are they used if at all? Hopefully on a safe level, as I imagine they are a low power sort.

Last edited by Holedigger on Wed Mar 25, 2009 1:15 pm, edited 1 time in total.

[Mudge]

Thank you kindly, troops. I never cease to be amazed at how little I know and how much youse troops do.

Mudge the enlightened

[TAdan]

Thanks for the info Taigh. I always noticed the antenna on the A-bombs but never knew what they were.