Airship Aircraft Carriers

[Caveman]

as deathjester says, one of the most common fallacies about airships, especially rigid hull airships is that they are pretty tolerant of small arms fire. Especially around the lower half of the gas bags, where diffusion is basically the problem. No comedy rubber balloon deflations.

Somewhat different with dirigibles as they require internal pressure to hold their shape

[KJ_Lesnick]

hobbes

Is there anyway you can do that computation regarding a vehicle with 18 aircraft and no armor plating and traditional skin but all the other variables the same?

deathjester

The most commonly used lift gas, helium, is inert so acts as a fire extinguisher.

Even if there were a considerable amount of fuel onboard?

[deathjester]

To an extent - it would reduce the fire hazard, but only within the gas bag(s).

Anything exposed to oxygen would be at risk of fire - best bet would be the self sealing fuel tanks that we already discussed.

Making the thing as much as possible out of materials naturally, or artificially fire retardant/resistant would also be a good plan.

As the piece I found on Wikipedia shows, rigid airships are surprisingly damage resistant anyway, and tacer/incendiary ammo would have little or no effect on the actual lift of the craft.

As an idea, for a modern variant of what you propose, how about using UAV's, with a small maintenance crew, and a small command crew, and a lightweight control console for the drones.  Good long endurance platform to search / destroy terror targets?

[KJ_Lesnick]

To an extent - it would reduce the fire hazard, but only within the gas bag(s).

Not the fuel tanks.  Would it have been feasible and would anybody have thought about putting the fuel tanks inside the gas-bags (like a concentric layout)

As the piece I found on Wikipedia shows, rigid airships are surprisingly damage resistant anyway, and tacer/incendiary ammo would have little or no effect on the actual lift of the craft.

What about the bridge/gondola?  That would need some armoring

As an idea, for a modern variant of what you propose, how about using UAV's, with a small maintenance crew, and a small command crew, and a lightweight control console for the drones.  Good long endurance platform to search / destroy terror targets?

The drones already have good endurance as is

[deathjester]

The drones do have good endurance, but this way can be refueled and rearmed on/near the battle area.  If you put fuel tanks inside the gas bags, you reduce the useable volume of the bags for the gas, so less livt force is available.  I think self sealing is good enough for what you want.

[Hobbes]

hobbes

Is there anyway you can do that computation regarding a vehicle with 18 aircraft and no armor plating and traditional skin but all the other variables the same?

My figures were for an airship without armor plating, and using the Hindenburg's basic construction. If you add armor you run into pyro-maniac's point. I'd estimate one operator position is a cell of 1 m x 1 m x 1.5 m, so that's 8 sq m of armor plate. If the plate is 1 cm thick, that's 640 kg of plate to protect one person, and one Hindenburg's worth of lift to protect 10 people.

Would it not be feasible to counteract the 'excess' lifting force by angling the engines down a bit...?

18 aircraft taking off is 7 tons of lift, so you'd need 7 tons of vertical thrust to counteract it. A random calculator page gives me 200 kg of thrust from 1000 shp, so you need 35,000 shp to keep the airship at a constant altitude.

[deathjester]

No probs.  Fit the airship with 8x Allison T-56's, which should give you around about 40,000 shp!!

[deathjester]

Or to fit in with the time period, make up 12 pairs of engines in the 1200, 1500 shp range - should be possible, yes?

[PR19_Kit]

Or to fit in with the time period, make up 12 pairs of engines in the 1200, 1500 shp range - should be possible, yes?

Maybe, but they'd just be the 'lift compensation' engines, and you'd still need some to make it go forward, and you'd need to take the weight of BOTH sets into effect not to mention the fuel for them..........

[Gondor]

Or to fit in with the time period, make up 12 pairs of engines in the 1200, 1500 shp range - should be possible, yes?

Maybe, but they'd just be the 'lift compensation' engines, and you'd still need some to make it go forward, and you'd need to take the weight of BOTH sets into effect not to mention the fuel for them..........

..... and then the crews to look after them, their billets and the food etc for them then the cooks to look after them etc etc etc....


Gondor

[deathjester]

Not at all, just have to angle them down a bit!  With forward motion you can also use aerodynamic control surfaces to provide extra down force...

[KJ_Lesnick]

18 aircraft taking off is 7 tons of lift, so you'd need 7 tons of vertical thrust to counteract it.

Hmm if I do my math right a P-40 was 6,400 pounds (early models) and later models were like 8800 pounds fully loaded and assuming they didn't carry more than 500 pounds of bombs it'd be around 7800 so...
7800 x 18 = 140,400 = 70.2 tons

A random calculator page gives me 200 kg of thrust from 1000 shp, so you need 35,000 shp to keep the airship at a constant altitude.

As I understand it you could get around 3.5 lbf per hp so that would be 3500 lbf per hp and that would give you 4,000 hp for that purpose but it's more complicated as a prop designed for an airship doing 73 miles an hour can be far better designed for low-speed and as the speed goes up net thrust goes down, admittedly you could optimize for maximum or cruise speed and also use a big prop.

[kerick]

Obviously only one thing can solve this problem...
Time Lord technology.. Bigger on the inside than on the outside....

[rickshaw]

A couple of points, catching up the thread.

The Schutte-Lanz airships weren't terribly successful.  A combination of a heavy structure (wood was heavier than the Zeppelin's metal), poor glues and wet timber being used.   Their lift was appreciably smaller than the Zeppelins and they had a bad tendency to fall apart in mid-air.   Most were relegated to training rather than operations.   The Zeppelin structure was an excellent design, for its weight and it wasn't until Barnes Wallis created geodetic structures was it bettered.

Of course the greatest vulnerability of all airships is the gas they utilised.  Hydrogen, mixed with oxygen was very flammable as we're all aware.  The USA cornered the production of Helium.   They utilised one of the few natural sources of the gas IIRC.  Interestingly, they have maintained their dominance with a Strategic Helium Reserve which they have only in the last decade or so allowed to run down.  If a cheap means of synthesise could have been developed in the early part of the 20th or the late 19th, then things would have been very different indeed, as far as powered flight was concerned.

To the question about having two, closely linked airships with a structure in between, that's been the study of several advanced airship concepts, such as the Skycat series which IIRC Lockheed took over.  The problem with it is that the structure connecting the two airships is essentially dead weight and subject to considerable torsional stresses, just like a sea catamaran structure.   Its an interesting solution and yes, it could form the basis of a airship aircraft carrier, with the planes being dropped through hatches in the floor.  However, I suspect such a structure would be unacceptably heavy using early 20th century materials and design.

As to putting an aircraft deck on top of an airship, the problem is that would make the airship top heavy and like all balloons, it would prefer to have the heaviest part of its structure on the bottom, with the result that unless substantial ballast was places below the airship's gas bags, it would invariably turn turtle.  As that ballast would be "dead weight", you'd be using a substantial part of your lift to just carry ballast.   Much more sensible again to put the hangar and launching system on the bottom of the airship.   You don't need a conventional carrier deck anyway, as you can just drop the plane and it would then gain sufficient lift from its own wings to fly.

[PR19_Kit]

You don't need a conventional carrier deck anyway, as you can just drop the plane and it would then gain sufficient lift from its own wings to fly.

But the difficult bit is, of course, 'landing' the thing afterward, as more than one pilot has found out.