Airship Aircraft Carriers

[KJ_Lesnick]

I: Would it have been physically possible to have built an airship in the 1930's with the following
-1: Stressed metal-skin and an internally braced metal skin (semi-monococque)
-2: An aircraft complement of either
--A: 18 full-sized aircraft including fighters, scout-bombers, torpedo-bombers (with foldable wings)
--B: 36 full-sized aircraft including fighters, scout-bombers, torpedo-bombers (with foldable wings)
--C: 54 full-sized aircraft including fighters, scout-bombers, torpedo-bombers (with foldable wings)
--D: 72 full-sized aircraft including fighters, scout-bombers, torpedo bombers (with foldable wings)
-3: Fuel for the ship and aircraft, and armament for the aircraft an adequate a number of sorties (not necessarily as long as a sea-based carrier as it travels faster)
-4: Crew accomodations for 2/3 of the carrier and air-wing crew onboard (similar to a submarine)?

II: With that being said, could such a design be built with any of the following
-1: An adequate degree of defensive armament (The Akron and Macon had guns on them) and ammunition for them
-2: Some type of armor to help resist battle-damage that would be subjected to it (similar in nature to a bomber)?
--A: The means to repair damage in flight
-3: Possibly a runway up top and elevator to bring aircraft and armament up top

III: If anybody has the slightest clue, was there anybody in the US who knew a thing about geodesic construction and the knowledge to make it work?

[PR19_Kit]

I'd say :-

I) No.

   My reasoning being that although a metal-clad airship had been built by then and successfully flown (the ZMC-2, see here http://en.wikipedia.org/wiki/ZMC-2) as far as I can see it wasn't 'internally braced' in the manner in which you're proposing. To carry that kind of air wing, even the smallest one of 198 aircraft, would have needed an ENORMOUS airship to provide enough lift to get that weight off the ground.

Although aircraft had been carried aboard airships, the Grumman Sparrowhawks aboard the 'Akron' and 'Macon' as an example, by then, they were only in small numbers, 18 would have been pretty darned heavy.

One thing that no-one seems to have considered in the aircraft carrying airship area is what happens to the 'ship when all its airwing has flown off? It then has LOTS more lift than it needs and will probably rise to its pressure height and blow off some gas, so what happens when the airwing comes back aboard? The 'ship is then too heavy to fly and will sink to the ground as it has no means of gaining more lifting gas in mid-air. The bigger the airwing the worse this problem will become.

II) Even less likely I'd say, for the same reasons I gave above. While the armarment and armour could no doubt be fitted, the airship then becomes larger and larger to generate enough lift to get all that extra weight off the ground. Just guessing I'd say we're already talking about something maybe 5 or even 10 times the size of the LZ-129 'Hindenberg', the largest airship ever built.

III) Maybe not geodetic construction, as non-geodetic rigid aiships had already been built, the 'Akron' and 'Macon' being just two examples. But the guys who built the ZMC-2 were headed in the right direction perhaps, but as usual their lords and masters just weren't thinking big enough, by perhaps a factor of 350.....?

[jcf]

Real world? No, for the reasons Kit states, however in the wonderful age of the Pulps, sure.
You could see something like that gracing the cover of Air Age or Popular Mechanics.

David Schwarz's designs of the 1890s were metal-skinned with internal bracing, the unsuccessful
Slate Corporation City of Glendale was built of corrugated planks.


The German Schütte-Lanz firm used a diagonal framing arrangement prior to WWI, and the first
geodesic dome was built as an observatory dome in Germany in the 1920s, so the basic concepts
behind geodetic/geodesic structure were well known. Anyhow geodesic is a geometry term that
refers to lines between points on the surface a sphere.


I don't see how a full Wallis-style geodetic structure would necessarily be of advantage in a huge airship,
and in world of 400 mph fighters such a beast is just a big fat target.

Kit, that would be the Curtiss Sparrowhawk. 

[KJ_Lesnick]

I) No.

   My reasoning being that although a metal-clad airship had been built by then and successfully flown (the ZMC-2, see here http://en.wikipedia.org/wiki/ZMC-2) as far as I can see it wasn't 'internally braced' in the manner in which you're proposing. To carry that kind of air wing, even the smallest one of 198 aircraft, would have needed an ENORMOUS airship to provide enough lift to get that weight off the ground.

Although aircraft had been carried aboard airships, the Grumman Sparrowhawks aboard the 'Akron' and 'Macon' as an example, by then, they were only in small numbers, 18 would have been pretty darned heavy.

How much heavier would that have been to carry

One thing that no-one seems to have considered in the aircraft carrying airship area is what happens to the 'ship when all its airwing has flown off? It then has LOTS more lift than it needs and will probably rise to its pressure height and blow off some gas, so what happens when the airwing comes back aboard? The 'ship is then too heavy to fly and will sink to the ground as it has no means of gaining more lifting gas in mid-air. The bigger the airwing the worse this problem will become.

II) Even less likely I'd say, for the same reasons I gave above. While the armarment and armour could no doubt be fitted, the airship then becomes larger and larger to generate enough lift to get all that extra weight off the ground. Just guessing I'd say we're already talking about something maybe 5 or even 10 times the size of the LZ-129 'Hindenberg', the largest airship ever built.

5 or 10 times the size of the LZ-129?  Do you mean, length, mass, volume?  I'm curious as to how big that would come out to in mass, length and so forth.

III) Maybe not geodetic construction, as non-geodetic rigid aiships had already been built, the 'Akron' and 'Macon' being just two examples.

I'm just suggesting geodesic because it's strong as hell, and lighter than regular construction methods.

But the guys who built the ZMC-2 were headed in the right direction perhaps, but as usual their lords and masters just weren't thinking big enough, by perhaps a factor of 350.....?

350 times heavier, 350 times more volume, etc?  Could you give me any ideas on size?

[PR19_Kit]

Seen one Hawk or Cat JCF, you've seen 'em all. I never was much good on bi-planes 

As for airship volumes it's a BITCH to do the calculations on length and diameter etc., I was working purely on volumes as that defines the amount of gas carried and thus the available lift. Because the ends of the airship aren't cones and the centre body isn't a cylinder calculating the exact dimensions isn't something my 70 year old engineer's brain is up to doing any more I'm afraid.

The 350 times larger than the ZMC-2 came from 10 times the difference in volume between the ZMC-2 and the Hindenberg.

For my own particular take on the 'aircraft carrying airships' theme see here :- http://www.whatifmodelers.com/index.php/topic,34363.0/highlight,airship.html

But please note I conveniently igonored the issue of the airwing flown away/airwing returned issue to generate the size of my mythical USN 'Island' Class airships.

[Rheged]

You may find Rudyard Kipling's short story "With the Night Mail"  stimulates thought. It might give some Whiffworld  answers to your problems.  It might also overstimulate some steampunk members.

Link 1  is a brief synopsis

http://www.kipling.org.uk/rg_withnight1.htm

Link 2  (if you scroll down a bit )  is the full short  story

http://wondersmith.com/scifi/mail.htm

[KJ_Lesnick]

As for airship volumes it's a BITCH to do the calculations on length and diameter etc., I was working purely on volumes as that defines the amount of gas carried and thus the available lift.

calculating the exact dimensions isn't something my 70 year old engineer's brain is up to doing any more I'm afraid.

You're 70 years old?  Wow -- I guess it's good to stay young at heart

The 350 times larger than the ZMC-2 came from 10 times the difference in volume between the ZMC-2 and the Hindenberg.

I'm thinking about something.  Would anybody in that era (USN, USAAF, RAF) have thought of building a design
1: With a flattened oval cross-section
2: Effectively use two airship hulls together with a space in the middle connecting the two

But please note I conveniently igonored the issue of the airwing flown away/airwing returned issue to generate the size of my mythical USN 'Island' Class airships.

How much higher would a ship carrying 18 planes (say F4F/P-40 weighted) go up after launching all it's planes?  I'm just wondering if it would be some ridiculous altitude like 20,000 feet or like 15,000 (which you can adapt humans for -- just spend a few weeks at 8,000 feet, then go up to 14,000 and you're set -- mountain climbers do this...)

[jcf]

Bearing in mind that the gas was actually contained in gas-cells/ballonets, which were very often drum-shaped,
one could apply relatively simple maths for volume. So haul out your calculator and have fun.

[PR19_Kit]

I'm not sure that the ZMC-2 used ballonets to contain the gas, at least it doesn't SAY that it used them. But of course the mega-ships that we're talking about would be a whole different ball of wax. Plus I've spent 40+ years pounding calculators and slide rules etc. and it's not fun any more.....

When they'd launched their air group the mega-ship would rise to its pressure height. That's the maximum height at which it was designed to fly and that depended on how strong the envelope or balonets were in order to contain the expanding lift gas. I guess that an all metal ship could have a higher pressure height so long as the ballonets were restrained by the 'envelope' itself. At the pressure height valves opened and dumped some of the gas whether the crew liked it or not, thus the loss of air group lifting gas that I mentioned earlier.

Who knows what direction the design thoughts would have gone? After all we're dealing with an impractical design philosphy here.

[kerick]

Were you thinking of an airship with a flight deck on top of the gas containing structure? I've seen some pictures of such and was wondering if that was what you were planning. My question with that arraigment was about the balance of the airship. Wouldn't that be very top heavy and subject to rolling over? While an airship carrying usable numbers of aircraft is very intersting I think it would require launching and recovering them from the underside.

[jcf]

ZMC-2 was directly helium filled without gas-cells, which fits with it being a metal hulled analog
of a blimp rather than a rigid airship. A larger rigid airship variation would probably have required
a compartmentalized gas-cell arrangement, for reasons of construction as well as the logistics
of filling and operations.

Could you imagine trying to fill a single volume the size of the Hindenburg? 

The calculator suggestion was for Kendra, she wants an answer, she can do the math. 

[PR19_Kit]

ZMC-2 was directly helium filled without gas-cells, which fits with it being a metal hulled analog
of a blimp rather than a rigid airship. A larger rigid airship variation would probably have required
a compartmentalized gas-cell arrangement, for reasons of construction as well as the logistics
of filling and operations.

Could you imagine trying to fill a single volume the size of the Hindenburg?  

OK, it mentions the filling of the ZMC-2 (was there ever a ZMC-1?) on the Wiki page and that they had to fill it with CO2 first to avoid dilution of the helium gas fill. Luckily someone figured the CO2 fill would make it heavier than normal first!  

The calculator suggestion was for Kendra, she wants an answer, she can do the math.  

Oh good, the only calculator I can find now is the one that comes with Win7!  

I can vaguely remember trying to do accurate volume calculations for curved fuel tanks while doing Auto Engineering in the middle 60s. It always drove me nuts, especially as we used slide rules in those days! (I still have mine......  )

[Rheged]

I can vaguely remember trying to do accurate volume calculations for curved fuel tanks while doing Auto Engineering in the middle 60s. It always drove me nuts, especially as we used slide rules in those days! (I still have mine......  )

I too  still have my trusty slide rule !  But how many people  in 21st century would even know what one was,  let alone how to use one.  My sons can,  but they have a head of  environmental systems design  and a senior maths lecturer as grandparents. 

If you need lift, It's easier to postulate "Fleury's Ray"  from the Kipling short story  or Space 1889  LIFTWOOD than do the  real world calculations.

[Caveman]

Perhaps this monster size airship is about big enough to consider carrying the facilities to liquefy and store some lifting gas when the air wing launch?

[NARSES2]

I can vaguely remember trying to do accurate volume calculations for curved fuel tanks while doing Auto Engineering in the middle 60s. It always drove me nuts, especially as we used slide rules in those days! (I still have mine......  )

I too  still have my trusty slide rule !  But how many people  in 21st century would even know what one was,  let alone how to use one.  My sons can,  but they have a head of  environmental systems design  and a senior maths lecturer as grandparents. 

Still have my old slide rule as well. The ones that threw me were the circular ones and then I went to the National Computer Museum at Bletchley and saw all the different types of "slide rule"