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

Jack Cook · **Posted:** Tue Mar 24, 2009 6:33 pm

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

The Inspector · **Posted:** Wed Mar 25, 2009 2:08 am

HAWULINAZZ

Mudge · **Posted:** Wed Mar 25, 2009 10:25 am

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

Mudge the visually challenged :shock:

daveymac82c · **Posted:** Wed Mar 25, 2009 10:36 am

Mudge,

I think those are "Cheap Seat Handles."

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

Mudge · **Posted:** Wed Mar 25, 2009 10:41 am

daveymac82c wrote:

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. :twisted:

Mudge the humorist :roll:

retroaviation · **Posted:** Wed Mar 25, 2009 11:14 am

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

Gary

Nathan · **Posted:** Wed Mar 25, 2009 11:17 am

haha yeah I was wondering where Jack ment too. :oops:

Mudge · **Posted:** Wed Mar 25, 2009 11:55 am

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 · **Posted:** Wed Mar 25, 2009 12:22 pm

...Hrududu.

spookythecat · **Posted:** Wed Mar 25, 2009 12:29 pm

Mudge wrote:

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 · **Posted:** Wed Mar 25, 2009 12:49 pm

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 · **Posted:** Wed Mar 25, 2009 12:51 pm

Mudge wrote:

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

Mudge the visually challenged :shock:

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

Holedigger · **Posted:** Wed Mar 25, 2009 1:05 pm

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

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.

Mudge · **Posted:** Wed Mar 25, 2009 1:07 pm

Thank you kindly, troops. I never cease to be amazed at how little I know and how much youse troops do. :drink3:

Mudge the enlightened

TAdan · **Posted:** Wed Mar 25, 2009 1:11 pm

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

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