This is my second question in the series Saturnian Cloud Cities. The first one is Would this concept for a cloud city on Saturn work?)
So, I am not going into details about the cloud-city here in question, but I am gonna do a quick recap:
The cloud city is essentially a large zeppelin, which consists of heated hydrogen. The source of the heat comes from long kronothermal cables
I call them kronothermal and not geothermal because Kronos (Saturn)+thermal=Kronothermal. These kronothermal cables dip down very deep into Saturn's atmosphere (but not even remotely close to the core or even the LH2 oceans) just below the water-ice cloud deck. The electricity is produced by means of massive titanium wind turbines which are durable, and spin under the intense winds of Saturn. For additional details, refer to this question.
However, now let's get back to the point.
Let's say, the airship has a launchpad that extends below the hull of the cloud-city. This launchpad is in question about 2 miles long and half-km wide. This launchpad is meant for launching planes which actually go deep down into the atmosphere to harvest water-ice, and go back to their launchbase. The plane's structure is as follows-
The plane resembles a Boeing-747, about 2x bigger. The only difference is that the plane is completely empty and is actually meant for holding water. The only part of the plane that is inhabited is the pilot-room. The rest of the plane is simply a empty place, meant for storing water.
The fuselage is made of titanium to withstand high temperatures and pressure.
The engine of the plane, is an air-breathing engine. However, this engine actually uses the hydrogen-rich air as an fuel, while oxygen is injected into the engine (In contrast to engines here on earth that inject fuel into the engine). The engine is a ramjet. The oxygen is question is obtained from the algae vessels from the cloud-city
The interior of the plane is lined with styrofoam for heat insulation.
The entire body of the plane is coated with fumed silica, an hydrophobic substance that prevents icing or damping.
The planes harvest water, by actually opening up a giant hole in the fuselage. This hole is filled with many wire-meshes. When the planes fly through the water-cloud deck, the clouds are rammed into the mesh, where they are absorbed, and allowed to drip into the water-hold. The idea is similar to Fog harvesters.
What are the problems with this aircraft design? If any, then what should I do to fix them?