[ARC5] SCR-718 in a KC-135

[D C *Mac* Macdonald]

Greetings, Taigh! 
 
Is that SCR-718 the same radio altimeter with a round 
scope about 3" in diameter that was in T-29 navigation 
training aircraft?  It's been 50 years since I had my 
nav training so nomenclatures have probably faded!  The 
ones we used had a circular pattern that read from 0 
to 5,000 feet or could also indicate 5,000 to 10,000 
feet of radio altitude to the ocean.  It did NOT state 
which but you should know whether you were at 2,000 or 
7,000 feet! There was a "pip" straight up at 0 and you 
averaged out the other one that varied with wave height. 
 
We used them overwater in conjunction with pressure 
pattern navigation. The aircraft flew at a steady 
pressure altitude and you compared the change (if any)
in pressure and radio altitude to estimate the drift 
and difference between air speed and ground speed to 
derive an estimated position. Not very exact, but it
might be all you had if sky was overcast and you could 
not get a "line of position" (LOP) from a sextant shot 
on the sun and/or moon. Going from USA across the big 
pond known as the Atlantic, you could pretty much 
figure you could find Europe or Africa!  (;<p)
 
* * * * * * * * * * * 
* 73 - Mac, K2GKK/5 * 
* (Since 30 Nov 53) * 
* k2gkk at hotmail.com *  
* Oklahoma City, OK * 
* USAF, Ret (61-81) * 
* * * * * * * * * * * 
 
(long ago B-52F EWO)



 
 
> From: Taigh at twinbeech.com
> To: arc5 at mailman.qth.net
> Date: Tue, 14 Aug 2012 14:57:54 -0700
> Subject: [ARC5] SCR-718 in a KC-135
> 
> Speaking of KC-135s... I was on a crew to fly the B-29 Hawg Wild 
> from Tucson to the Imperial War Museum in Duxford England in 1980. 
> We stopped for a week at Loring AFB in Maine for repairs in 
> preparation for the trip across the Atlantic.
> 
> We had some nice base tours while we were there and a B-52 navigator 
> named Jake Huffman had taken us in a B-52 going through overhaul and 
> then we got to go inside a KC-135. I was astonished to see the 
> indicator for the SCR-718 radio altimeter mounted on the left side 
> of the Navs panel. It was complete with DAY-44 on the data plate. 
> What a surprise to see a WWII radio installed in a current Air Force 
> aircraft, well current for 1980 anyway.
> 
> 
> Taigh
> 
> Taigh Ramey
> Proprietor, Vintage Aircraft
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