[Milsurplus] "Antenna Tensioners" available

[Michael Hanz]

On 8/2/2021 1:31 AM, KD7JYK DM09 wrote:
>> Well, I wouldn't call them totally foolproof.  They work well in most 
>> cases, but dust storms, insects, and salt spray can cause them to 
>> jam. I've had a couple of examples from the Arizona boneyards that 
>> were bound up pretty well.
>
> I forgot about the enclosed ones...  Yeah, they suck.  I was thinking 
> the exposed models, kinda self-clearing.

I certainly agree, from a pure functionality perspective.  The enclosed 
tensioners (and the rubber type) have one thing going for them - they 
are more aerodynamic and introduce less turbulent drag than the open 
spring and arrestor/limiter hardware type.  I think that's why the open 
type never became mainline with military aircraft during the war.  From 
almost the beginning of aircraft design for non-fabric flight elements 
in the 1930s , there was a huge effort to reduce drag, even with low 
profile devices like countermeasures antennas and DF loops - note the 
black "football" for the Bendix automatic DF loops on a huge number of 
the aircraft. There were a lot of wind tunnel runs on ways to reduce 
drag for these seemingly minute elements, and a lot of swoopy Plexiglass 
covers were designed for them.  The B-29 is a good example of attention 
to such details, even going so far as replacing the usual conical 
ceramic HF feedthrough insulators with this streamlined type (we are 
still looking for one to join an original on the Enola Gay, by the way):


As for the fragile nature of the rubber type, I dunno - they had an 
amazingly long run with the same NAF part number from the early 1930s to 
the end of the war.  If they were that delicate, I don't see the Navy 
sticking with them for so long - NRL was a hotbed of research into all 
things aircraft related and surely studied the problem.

- Mike   KC4TOS

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