Cold War ALternate Basing

In article ,
Andrew Chaplin writes:
Kevin Brooks wrote:

No, I drove it last month while on vacation, and as a civil engineer I
typically *do* note the things that the average passerby might ignore (such
as, "Hey, look at those neat masonry arch bridges that parallel I-81 along
this stretch...wonder what their story is? (Turned out to be an old railroad
route after investigating further)).

Hmm. I suppose the constant re-application of lessons learned as young
adults is a fairly common trait. I find myself looking at woods and
open areas as I go along the highways and byways, not as landscape and
scenery, but as crest hazards, flash cover and locations for gunlines,
command posts, battery echelons, wagon lines, positions of assembly,
rendez-vous for recce parties, ammo drops, laying up areas, hides,
OPs, air sentry posts, AAA positions.... :^)

That's not entirely a futile practice. The best spots tp put tank in
turret defilade or hull defilade to cover a stretch of road are also
the spots that the local Gendarmerie use for setting up radar traps.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

"Chad Irby" wrote in message
.. .
In article ,
"Kevin Brooks" wrote:

"Chad Irby" wrote in message
. ..

You keep insisting that normal highway construction techniques just
won't work for aircraft runways, when the FAA tells us just the
opposite:

http://www.faa.gov/arp/pdf/5100-13a.pdf

A quick summary: for runways for planes under 60,000 pounds, with over
200 psi tire pressure, highway construction techniques are sufficient,
according to the FAA, for thousands of landings per year, as long as
minimum thickness of the surface is followed - and that thickness is
less than the standard for Interstates in most of the U.S.

LOL! Try again. That says the *methodology* is acceptable--not some kind
of
simple "one pavement fits all". If you bothered to READ the document,
you
would have noted that it also starts out the pavement section with:
"...standards developed for pavement design should consider: (a) maximum
gross weight of aircraft, (b) gear type and configuration, (c) traffic
volume and distribution, (d) strength of subgrade soil"

So, Mr. Wizard, tell us *how* it's different...

Already have, repeatedly. Go take a gander at those tables you forgot to
consider when you tried this ill-fated ambush of yours.


You keep bleating about how it's all completely different, but it's
funny how you can't actually tell us *how* it's different, other than to
toss a few technical phrases out there with no actual numbers attached...

Impact loads, wheel loading, number of axles (how many heavy truck loads do
YOU know of where the majority of the load is centered on a single axle, as
it is on a tactical fighter?), etc. Done and done and done again and
again--work on that reading comprehension of yours, Chad--it might keep you
from providing evidence for your opponents' claims, as you did by pulling up
that FAA document. And thanks again for that... Get back to me when you have
your CE degree in hand, OK? 'Cause so far, your grasp of the basics has
proven to be pretty sad--how is that "really big shaped charge" of your's
coming, by the way?

Brooks


So, given equivalent soil conditions, what *are* the differences between
a standard Interstate highway and one of the runway designs mentioned
above (handling a 60,000 pound aircraft with 200 psi tires)? Build them
right next to each other, parallel, same rainfall amounts. Let us know
what you figure out.

You have a major talent for telling us that something is impossible, but
come up really short on using that amazing engineering skill to show
your work...

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

In article ,
Guy Alcala wrote:

Which would seem to be an appropriate place to step in and provide tire sizes
and pressures for the AV-8B and F/A-18C/D, from Jane's:
-----------------------------------------------------------------

AV-8B (S/L ISA max VTO weight 20,595 lb. w/ -408 engine. MTOGW 31,000 lb.).

Landing Gear: Retractable bicycle type of Dowty design permitting
operations from rough unprepared surfaces of very low CBR (California
Bearing Ratio) . . . Single steerable nosewheel . . . twin coupled
mainwheels . . . small outrigger units . . . Mainwheel tyres (size
26.0 x 7.75-13.00) and nosewheel tyre (size 26.0 x 8.75-11) all have
pressure of 8.62 bars (125 lb/sq. in.) Outrigger typres are size
13.5 x 6.00-4.00, pressure 10.34 bars (150lb./sq. in.).

F/A-18C/D (t/o weight fighter mission 36,710 lb., attack mission
51,900 lb., MTOGW 56,000 lb.)

Landing Gear: Dowty retractable tricycle type, with twin wheel nose
and single wheel main units . . . Nosewheel tyres size 22 x 6.6-10,
20-ply, pressure 24.13 bars (350 lb./sq.in) for carrier operations,
10.34 bars (150 lb./sq.in) for land operations. Mainwheel tyres size
30 x 11.5-14.5, 24-ply, pressure 24.13 bars (350 lb./sq.in.) for
carrier operations, 13.79 bars (200 lb./sq.in.) for land operations.
-------------------------------------------------------

What's patently clear from the above, even if Jane's didn't spell it
out in so many words, is that the Harrier gear provides a much lower
ground pressure than a CTOL fighter.

Well, "much lower" in the sense of running the main tires at 62.5% of
the pressure of the land-based F-18. In other words, the F-18 puts less
than twice the PSI on the ground, not an extreme amount for concrete,
which should be able to handle well over 600 PSI...

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

On 07 Aug 2004 04:47:48 GMT, (BUFDRVR) wrote:

John Hairell wrote:

I used to work at an airfield that had an 11,000 foot runway and ramps
and taxiways designed to handle fully-laden B-52s. Loaded C-5s would
often buckle the concrete

Hmmm, this doesn't make sense. The B-52 psi "footprint" is heavier than any
other USAF aircraft. Between our twin tandom gear and our relatively small
wheels, a fully loaded B-52 has a ridiculously high psi....at least that's what
we were told and what AP-1B bears out.



I'm not saying that loaded B-52s would never have buckled the concrete
either, we just never had any visit to put it to the test.
Regardless, the airfield was built originally to handle B-52s, and
I've seen fully-loaded C-5s buckle the concrete.

John Hairell )

Chad Irby wrote:

In article ,
Guy Alcala wrote:

Which would seem to be an appropriate place to step in and provide tire sizes
and pressures for the AV-8B and F/A-18C/D, from Jane's:
-----------------------------------------------------------------

AV-8B (S/L ISA max VTO weight 20,595 lb. w/ -408 engine. MTOGW 31,000 lb.).

Landing Gear: Retractable bicycle type of Dowty design permitting
operations from rough unprepared surfaces of very low CBR (California
Bearing Ratio) . . . Single steerable nosewheel . . . twin coupled
mainwheels . . . small outrigger units . . . Mainwheel tyres (size
26.0 x 7.75-13.00) and nosewheel tyre (size 26.0 x 8.75-11) all have
pressure of 8.62 bars (125 lb/sq. in.) Outrigger typres are size
13.5 x 6.00-4.00, pressure 10.34 bars (150lb./sq. in.).

F/A-18C/D (t/o weight fighter mission 36,710 lb., attack mission
51,900 lb., MTOGW 56,000 lb.)

Landing Gear: Dowty retractable tricycle type, with twin wheel nose
and single wheel main units . . . Nosewheel tyres size 22 x 6.6-10,
20-ply, pressure 24.13 bars (350 lb./sq.in) for carrier operations,
10.34 bars (150 lb./sq.in) for land operations. Mainwheel tyres size
30 x 11.5-14.5, 24-ply, pressure 24.13 bars (350 lb./sq.in.) for
carrier operations, 13.79 bars (200 lb./sq.in.) for land operations.
-------------------------------------------------------

What's patently clear from the above, even if Jane's didn't spell it
out in so many words, is that the Harrier gear provides a much lower
ground pressure than a CTOL fighter.

Well, "much lower" in the sense of running the main tires at 62.5% of
the pressure of the land-based F-18. In other words, the F-18 puts less
than twice the PSI on the ground, not an extreme amount for concrete,
which should be able to handle well over 600 PSI...

You've only mentioned the tire pressure, without calculating the respective contact
areas and then dividing the weight of each a/c by that (which is fine if the a/c
isn't moving, but then there's descent rate and landing speed to factor in as
well).

An AV-8B (usually) lands vertically, sinking down onto an air cushion (think air
hockey puck) trapped between the air dams formed by the strakes and speed brake,
and then reduces power further to touch down, i.e. a descent rate of a few fps at
essentially zero forward speed. An F-18 will land on a runway at say 130 knots,
with a descent rate that is probably higher (albeit a lot less than the 24 fps max.
descent rate carrier landing the gear is designed for), say 6-10 fps typical if
you're making a flared landing. If you want/need to make a short, arrested
landing, it's a lot closer to a carrier 'controlled crash' with higher descent
rates.

Guy