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From: anderson@erim.org (Rod Anderson)
Newsgroups: sci.military
Subject: Re: Airships
Message-ID: <1991Jun15.021446.29810@amd.com>
Date: 14 Jun 91 13:50:59 GMT
Sender: military@amd.com
Organization: Advanced Micro Devices, Inc.
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From: anderson@erim.org (Rod Anderson)


>anasaz!qip!john@asuvax.eas.asu.edu writes:
>>daly@strawber.princeton.edu (John Daly) writes:
>>[airship capabilities discussion deleted]

>I disagree.

>Nuclear submarines reportedly can exceed 40 knots submerged. 

Presumably to outrun airships. My 1954 Jane's quotes a top speed of
"over 85 mph" (>75K) for the Navy's N class blimp. A definite speed
advantage to the blimp.  In any case, submerged speeds of ~40K would
result in VERY long passive acoustic detection ranges.  For this
reason, high speed is probably used only in extremis (e.g., weapon
evasion, departing a flaming datum...).  At this point, he's forfeited
stealth, which is what you want to do (aside from sinking him!):-)

>P-3's can be sent thousands of miles at 425 knots in order to
>participate in ASW (we used to investigate SOSUS contacts at the
>international date line from an airbase near San Francisco). That's
>going to be tough to do in an airship.

P3 does have good range, but I recall max range airspeed was more like
330K TAS.  How much on-station time did you have on your example
mission?  Less than 4 hours out of a 12 hour mission would be my
estimate.  How many crews and aircraft were needed to maintain at least
one P3 on station, even with no maintenance problems and minimum crew
rest?  My guess: 5 aircraft, 8 crews.  This is for one contact!

Incidentally, the P3's slow transit speed was an issue in the P-7
competition.  Both Boeing and Douglas proposed mods of commercial jets
(757, MD-80 ??), and touted the speed advantage.  Wasn't decisive,
though!!

>Incidently, our hangar previously housed an airship used for ASW circa
>WW-II (USS Macon, I believe). The airship was destroyed in a storm.  I
>would say that the airship is an obsolete ASW weapon.

All airships used in WWII were blimps; USS Macon was a prewar dirigible.

We need to establish what kind of ASW we're talking about: 1. open
ocean search (SOSUS or SURTASS cued), 2.  bastion penetration (Maritime
strategy style), 3. convoy escort, or 4. direct BG support.  Because of
its speed, the P3 does a good job in #1, is hopeless in #2 (too
vulnerable), and is marginal in #3 and #4 (limited onstation time,
vulnerability). SSN's excel at #2, and are pretty good at #3 and #4.
(Coordination with convoy/BG can be a problem).

Airships are an intermediate platform between fixed wing aircraft and
ship/submarines in terms of speed and endurance.  Convoy escort in
particular seems ideally suited for them.  They could conduct search
and localization using sonobuoys, ESM, and FLIR just like the P3.  If
dipping sonar could be installed,  an airship could prosecute the
entire ASW problem, perhaps assisted in the weapon delivery phase.  MAD
localization is the only area in which an airship would be inferior to
a fixed wing platform, IMHO. Conclusion, airships would excel at #3,
and do OK in #4.

OBTW, blimps performed extensive convoy escort duty during WWII,
especially in the "Black Pit" (out of range of land based air).  Number
of ships lost while escorted by airships: NONE.  Is there a lesson here?

Rod