Airship Colossus Drone Carrier Design is Complete!!

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!

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Comment by Wes Collins on September 24, 2011 at 8:31pm

I would actually recommend lowering the craft down to either a ship at sea for an unrep (underway replenishment).  It could also be accomplished at any airport with helium blimp facilities.  So, the airship itself would not actually have to be married to a single geographic location for it's operability.  It would be easier for an automated system to drop a hose that a person plugs into a replenishment tank than it would to make a fully automated airtight replenishment connection while in-flight.  However, I think in-flight helium replenishment would be able to be accomplished if the airship had a pilot aboard as they could plug a hose dropped from a replenishment plane into the necessary intake nozzles mounted in the control gondola.  Sort of a helium probe and drogue as it were.

Comment by Wes Collins on September 24, 2011 at 8:34pm

But again, the rigid frame would need to be checked and tightened at least once every 7 days to ensure frame strength.  But coming down to the ground for about 6 hours every 7 days doesn't really make much of a difference considering the area that can be covered the rest of the time it's up there...

Comment by bGatti on September 24, 2011 at 8:45pm

I would imagine a more slack tethering system would hold more promise.

 

If those drone-holds are rigid, then the structure must absorbs in an instant, the full force of the delta-v * m.

 

Perhaps a slack-line tether, similar to an inflight fuel line...

 

 

Comment by Wes Collins on September 24, 2011 at 8:53pm

There is almost no force being applied to the recovery trapeze while the aircraft is hooking on.  The difference between speeds is negligible.  Remember, the airship and the drone both will be travelling at speed of approximately 30-40mph as the drone is hooking on.  Not the same type of landing environment as a naval aircraft carrier so it doesn't need the braking equipment needed to land a jet on the Nimitz.

Comment by Wes Collins on September 24, 2011 at 8:56pm

Don't forget, the US Navy actually did this with real pilots flying Curtiss FC-9 Biplanes on 4 different airships from 1924 to 1936.  The airships, and airship carrier program as a system wasn't a failure, it was airframe design flaws for the airship itself coupled with bad piloting that brought down the American airship carrier program launching and recovering the planes ended up being the easiest part to carry off.


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Comment by Michael Pursifull on September 24, 2011 at 9:08pm
I have no experience with LTA, but I do have some flight tethering experience. How do you address static discharge on recovery?
Comment by Wes Collins on September 24, 2011 at 9:11pm

The rigid frame of the flight nacelle is a faraday cage in and of itself.  That's always been one of the upshots of rigid airship design.  The recovery equipment is coated with nonconductive materials.  It could be struck by lightning several times without affecting flight handling characteristics or damaging on-board equipment.  This is one of  the primary reasons I went with a hybrid rigid design.

Comment by Wes Collins on September 24, 2011 at 9:24pm

Another way to save on lifting gas is to purify it once a week, rather than replenishing.  Helium becomes contaminated over time and must be filtered to retain lift.  You use a lot less helium this way.  At 160' long, even as a UAV this is getting into a much larger class of aircraft which requires different maintenance procedures than say the average "party blimp" of 30' or less.  It becomes more cost effective to operate the larger it gets.  It actually costs quite a bit comparatively to run smaller airship platforms.  It doesn't really start becoming cheap again until you get under 10'.  20 to 60' are very cost prohibitive operational platform sizes.  My 20' flight test model will probably require upwards of $400 or more worth of helium just for the initial flight tests.  I'm hoping I can find some partners or donors by then...

Comment by Wes Collins on September 24, 2011 at 9:48pm

The intended powerplants are 12 UQM Technologies EV-218 Three Phase Brushless DC motors (that each weigh 110 lbs including the gearbox) each putting out 71 horsepower with 2 auxilliary Textron Lycoming IO-360 air-cooled flat-four 200 horsepower engines mounted in the main hull (one in the gondola, the second in the sensor bay both connected to the charging system of all three nacelles.

Comment by Dusan on September 25, 2011 at 10:51am
Doesn't helium lose buoyancy with low temperatures exceptionally, and if, how do you plan to compensate

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