As you can see, my airship design has reached a much more advanced stage. I will be constructing a balsa/lightweight plastic 20' flight test test model in my 2 car garage over the winter. Once the airframe passes some tests not conducted in a computer generated wind tunnel then hopefully it will be on to building an even bigger one. This finished Colossus will measure 160' in overall length and 72' wide for the airframe and she'll stand 118' from the strut to the main rudder.
Powered by 12 electric 6 blade vectored thrust props which will be able to steer the craft in something like the airship version of three rectangular arducopters bolted to each other. Not only will the housings pivot to allow more stable ascent/descent, the props also pivot out within the housing to allow lateral thrust capibilities.She'll be very maneuverable, and computer testing indicates the airframe will capable of some new maneuvers previously unknown to rigid and semi-rigid airframes such as lateral crabbing, and pivoting in a full 360 ciricle on her center-point within her own shiplength while making a vertical ascent or descent. This is a design change which can enable much safer landings and take-offs in windy conditions and perhaps prevent the pilot error which led to the hindenburg diaster from ever happening again.
The connection pylons between the main hull and the flight nacelles are airfoils which have air current forced over them by the forward engines. This adds to the lift and stability of the craft allowing it to reach higher speeds than have previously been attained by similar craft, and is one of the design features which should enable it to perform some fairly impressive maneuvers once in the air.
The main hull is semi-rigid with a pressurized envelope, similar to the Zeppelin-NT, however with a different internal framing configuration (obviously such would be necessary) and the flight nacelles have a lightweight rigid configuration with semi-pressurized helium cells.
She will be able to be operated fully autonomously, remotely operated by a single pilot wile the drones operate autonomously, or the gondola can easily be reconfigured to allow a single pilot to physically control the vessel if desired. The gondola also houses the auxilliary electric generator to allow for operation in a cloudy environment or if the solar electric system fails for whatever reason.
The battery banks providing power to each of the engine-pairs are located amidships and each nacelle is independently powered and recharged. The odd pattern of the solar cells are based on the weight of the lightweight flexible amorphous panels I could find information on. That pattern represents the best weight distribution to be able to achieve independent powering.
The drone launch and recovery system, mechanically, will be very similar to the original system designed for the USS Macon, Akron, and Los Angeles. However the drones will have cradle supports which lower fore and aft (not detailed in these photos, nor is the drone fuselage configuration to enable launch/recovery)
She's carrying 8 scaled down lightweight electric versions of the MQ-1 which are recharged by the on-board solar system. The drone wingspan is 18 feet. It is capable of carry drones with up to a 24' wingspan and gross weight of 350 lbs per plane. and obviously the system could be reconfigured to accomodate smaller craft. The way it works is really cool. The craft are stored so close together that instead of having a lowering design for launch, I worked it in to the craft are stored at different distances from the hull. The fore and aft drones are stowed 7" lower than the amidships drones.
The drone launch process will have to occur in a paired sequence for balance purposes, and the thrust configuration greatly stabilizes the craft and makes her a lot easier to balance, so the stowage level only makes it easier to conduct the launch sequence and it keeps the drones closest to the most balanced point. Once all the drones are away, the launch/recovery hooks raise up into the rigid hull of the flight nacelle and are kept close to the hull to increase aerodynamics. When it is time to recover the craft, the L/R trapeze descends to its full length to allow recovery of in-flight craft after others have already bee recovered.
The on-board sensor package is pretty modular actually. You can do a lot with this airship configuration. I have hard mounted fore and aft gimbals on the main hull and amdships gimbals on each flight nacelle. The bay in the main hull is also a sensor bay and acess panel. Fuel stowage for the auxilliary generator is in wing tankage in the two airfoils and the ship will carry approximately 4-8 hours worth of fuel currently, but more fuel storage can be added.
Unfortunately the laws of physics concerning rigid and semi-rigid airships dictate that the 20' model will be able to lift it's own airframe and that's about it. I should be able to include a single mini-cam on a gimbal but that's really it. She won't be able to carry a functional payload until she's at least 80' in overall length and even then we're talking some pretty small (under 100 lb each) planes.
I'll post more photos and stuff as they are generated and more news on this project and how it's going. Till then. Happy Flying!
Comments
How is the helium contained/retained? I understand helium balloons and weather balloons have a lifespan often measured in hours, as they leak helium. Do you "refit" with onboard tanks (seems like a never-ending weight-lift cycle to carry pressurized helium) and does this limit the flight time? Are there multiple layers to the helium bladders to prevent loss? What type of material is used? Apologies if these are basic questions.
The approximate gross weight of the unladen ship will be 26,000 lbs. She will be carrying almost 600,000 cubic feet of helium in all 3 nacelles. The Zeppelin NT weighs 23,000 lbs and carries 291,000 cubic feet of helium. In other words, almost enough helium to lift twice her weight. She will only be carrying a fraction of that fully loaded. Each drone at around 400 lbs plus the weight of 190lb pilot (if you even have one)
Miyazaki called - he wants his airships from LAST EXILE back. :) nice work.
You generally calculate intended gross weight by cubic volume of helium to determine lift characteristics. So many cubic feet of helium can lift so many pounds of weight. Rigid and semi-rigid designs are far more versatile than the sole remaining airship type, the blimp. Blimps you can really only usefully build so big. There is virtually no limit to the size you can achieve with a frame.
My design would require a larger main hull if it were a rigid design. The pressurized envelope allows for a greater amount of helium to be used in a smaller space achieving the same lift. Likewise the flight nacelles would also have to be larger if they were going to carry the weight of even 2 people and their crew accomodations (even if it was just a sitting station). All of this is possible and much of it is also on another one of my drawing boards but this is a drone community not a giant airship community.
Nice to see, thanks. Did you have an estimate weight (without the planes)?
Yes. The carrier matches the flight speed of the drone. Slows down another 5-7 kts and the the drone comes up to meet the hook. Once hooked on, the hook is raised up from inside the girder and the center of the fuselage is nested into the center cradle (which is shown in the photos) as fore and aft stabilizers are lowered onto the fore and aft of the drone fuselage and the entire assembly raises into the nacelle to stabilize the craft for full airship flight operational capability.
The airship itself should be able to attain speeds of 60 kts or greater. Drone launches also occur at higher altitudes than recovery. The drone is launched at a higher altitude than it is capable of achieving under it's own power. The airship must descend to recover the craft.
Much of the launch/recovery appratus is not detailed in these images because I have not drawn them into google sketchup yet. I've already gone through what amounts to be an entire young Pine trees worth of paper trying to figure out how the launch and reocvery sequence would work. I'll post up more images of that once they are generated but my google earth skills are a lot less well developed than my pencil and eraser skills.
Don't worry, I'm not an "aeronautical engineer" either. I just know airships really well and think that they are one of the most versatile air platforms humanity has ever devised. I learned airships from studying Eckener and Arnstein's work. They are the "not aeronautical engineers either" who designed the Zeppelin and the Akron/Macon. In fact, Arnstein was an architect before he designed the Akron and Macon.
wow. I am not at all familiar with the math behind a LTA design, are there some calculations you might be able to share? How does recovery of the drones work? Again, I am not an aeronautical engineer, but I understand from other forum posts that for small drones, we might expect perhaps approximately 30mph to sustain the drones weight via wing lift, will the Carrier need to match that speed for recovery? Very curiously yours.
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