Maximum aircraft weight a carrier catapult can launch?
J
aircraft weight that an aircraft carrier's catapult can launch?
Background:
I am currently reading "On Yankee Station" by Nichols and Tillman
(1987). In the last full paragraph on page 102, the authors write:
"[snip]...Then the exhilarating rush as the steam-powered cats flung
airplanes off the desk. Whether it was the A-4 grossing 20,000 pounds
with fuel and ordnance biting into the air or a huge KA-3 tanker
weighing 73,000 pounds lifting off, the procedure never failed to
fascinate me: from zero to 160 knots in three seconds."
Thanks . . . J
Walt
wrote:
Don't know what it is today, but there is certainly nothing as big or
heavy on a KA-3 on a carrier these days.
Dave Bowles
says...
The cats haven't changed much over the years. The A-3 was about the
biggest thig to ever get catted off the pointy end, and that 73,000
pounds was approaching the max. I recall 80,000 pounds from a chat many
years ago. An article on an NAS Lakehurst site tells of shooting a
79,000 pound sled, so that's about right.
Dave in Sandy Eggo
euno...@yahoo.com.au
> In article <nqbio6p7sev4b5s8prsd3sd9mt3varl...@4ax.com>, vzl...@q.com
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> > On Mon, 21 Mar 2011 02:59:18 -0700 (PDT), J <emer...@excite.com>
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> - Show quoted text -
I'm assuming there is no "weight" limit on the catapult. The immagine
the catapult would have a broad specification of
1 firstly the force it can generate at say zero speed.
2 secondly the maximum speed it can reach.
3 maximum power it can transfer.
4 the amount of energy it can transfer (I assume there is some kind of
steam reservoir or accumulator)
There might be a weight limit on the deck. I see no reason say a
160,000lb aircraft can't be launched so long as it can be accelerated
to above its stalling speed which of course needs to be lower the
larger the aircraft gets.
In the 1930s the Germans were catapulting the 38,500lb 4 engined Blohm
& Voss Ha 139 using a pneumatic catapult.
Steven P. McNicoll
>
> The cats haven't changed much over the years. The A-3 was about the
> biggest thig to ever get catted off the pointy end, and that 73,000
> pounds was approaching the max. I recall 80,000 pounds from a chat
> many years ago. An article on an NAS Lakehurst site tells of shooting
> a 79,000 pound sled, so that's about right.
>
Carrier suitability trials of the already-cancelled F-111B were conducted on
Coral Sea in 1968. That aircraft had a nominal "loaded weight" of 79,000
pounds.
John Weiss
>
> I'm assuming there is no "weight" limit on the catapult. The immagine
> the catapult would have a broad specification of
> 1 firstly the force it can generate at say zero speed.
> 2 secondly the maximum speed it can reach.
> 3 maximum power it can transfer.
> 4 the amount of energy it can transfer (I assume there is some kind of
> steam reservoir or accumulator)
>
> There might be a weight limit on the deck. I see no reason say a
> 160,000lb aircraft can't be launched so long as it can be accelerated
> to above its stalling speed which of course needs to be lower the
> larger the aircraft gets.
>
> In the 1930s the Germans were catapulting the 38,500lb 4 engined Blohm
> & Voss Ha 139 using a pneumatic catapult.
>
>
http://www.century-of-flight.net/Aviation%20history/coming%20of%20age/Blohm%20und%20Voss%20Ha.139.htm
The theoretical limit would be the total energy (E=mv**2) that can be
transferred in the distance allowed by the cat stroke. With a
constant-pressure system, the force applied is essentially constant, so
the acceleration would also be essentially constant. Theoretical max
force at the cat piston would be the max (nominal 1200 psi) steam
pressure of the ship's system times the surface area of the piston.
Acceleration would then be inversely proportional to the mass of the
airplane (F=ma), so end speed would be limited by total energy
available.
If you know the steam pressure, diameter of the cat piston, and the
length of the stroke, you could calculate a theoretical max force
applied, and then the max energy available. Of course, system friction
losses and component limits would reduce that somewhat. Mass of the
airplane would be limited by required end speed (stall + margin -
headwind).