Maybe Your Next Robot Should Be A Cyclocrane

At my university, we were all forced to take a class called Engineering 101. Weirdly, we could take it at any point in our careers at the school. So I put it off for more interesting classes until I was forced to take it in one of my final years. It was a mess of a class and never quite seemed to build up to a theme or a message. However, every third class or so they’d dredge up a veritable fossil from their ranks of graduates. These greybeards would sit at the front of the class and tell us about incredible things. It was worth the other two days of nondescript rambling by whichever engineering professor drew the short straw for one of their TAs.

The patent drawing.
The patent drawing.

One greybeard in particular had a long career in America’s unending string of, “Build cool stuff to help us make bad guys more deader,” projects. He worked on stealth boats, airplanes with wings that flex, and all sorts of incredibly cool stuff. I forgot about the details of those, but the one that stuck with me was the Cyclocrane. It had a ton of issues, and as the final verdict from a DARPA higher-up with a military rank was that it, “looked dumb as shit” (or so the greybeard informed us).

A Cyclo-What?

The Cyclocrane was a hybrid airship. Part aerodynamic and part aerostatic, or more simply put, a big balloon with an airplane glued on.  Airships are great because they have a constant static lift, in nearly all cases this is buoyancy from a gas that is lighter than air. The ship doesn’t “weigh” anything, so the only energy that needs to be expended is the energy needed to move it through the air to wherever it needs to go. Airplanes are also great, but need to spend fuel to lift themselves off the ground as well as point in the right direction. Helicopters are cool because they make so much noise that the earth can’t stand to be near them, providing lift. Now, there’s a huge list of pros and cons for each and there’s certainly a reason we use airplanes and not dirigibles for most tasks. The Cyclocrane was designed to fit an interesting use case somewhere in the middle.

In the logging industry they often use helicopters to lift machinery in and out of remote areas. However, lifting two tons with a helicopter is not the most efficient way to go about it. Airplanes are way more efficient but there’s an obvious problem with that. They only reach their peak efficiency at the speed and direction for which their various aerodynamic surfaces have been tuned. Also worth noting that they’re fairly bad at hovering. It’s really hard to lift a basket of chainsaws out of the woods safely when the vehicle doing it is moving at 120mph.

The cyclocrane wanted all the efficiency of a dirigible with the maneuverability of a helicopter. It wanted to be able to use the effective lifting design of an airplane wing too. It wanted to have and eat three cakes. It nearly did.

A Spinning Balloon with Wings

Four wings stick out of a rotating balloon. The balloon provides half of the aerostatic lift needed to hold the plane and the cargo up in the air. The weight is tied to the static ends of the balloon and hang via cables below the construction. The clever part is the four equidistant wings sticking out at right angles from the center of the ship. At the tip of each wing is a construction made up of a propellor and a second wing. Using this array of aerofoils and engines it was possible for the cyclocrane to spin its core at 13 revolutions per minute. This produced an airspeed of 60 mph for the wings. Which resulted in a ton of lift when the wings were angled back and forth in a cyclical pattern. All the while, the ship remaining perfectly stationary.

There’s a really great description of its operation in the article this photo came from.


It really didn't like strong winds.
It really didn’t like strong winds.

Now the ship had lots of problems. It was too heavy. It needed bigger engines. It was slow. It looked goofy. It didn’t like strong winds. The biggest problem was a lack of funding. It’s possible that the cyclocrane could have changed a few industries if its designers had been able to keep testing it. In the end it had a mere seven hours of flying time logged with its only commercial contract before the money was gone.

However! There may be some opportunity for hackers here. If you want to make the quadcopter nerds feel a slight sting of jealousy, a cyclocrane is the project for you. A heavy lift robot that’s potentially more efficient than a balloon with fans on it is pretty neat. T2here’s a bit of reverse engineering to be done before a true performance statement can be made. If nothing else. It’s just a cool piece of aerospace history that reminds us of the comforting fact that we haven’t even come close to inventing it all yet.

If you’d like to learn more there’s a ton of information and pictures on one of the engineer’s website. Naturally wikipedia has a bit to say. There’s also decent documentary on youtube, viewable below.

Photo Credits: Rob Crimmins and Hal Denison

43 thoughts on “Maybe Your Next Robot Should Be A Cyclocrane

  1. I see what you’re doing here.

    “Here’s an awesome machine I’d like to see exist… ‘Hey, hackers, wouldn’t it be cool if one of you were clever enough to handle building this?'” *simply waits*

  2. Isn’t it simply a quad- (or hex-) copter with a balloon for lift? If so, the technology to control the props wasn’t there at the time, but is certainly state-of-the-art today.

    1. The dynamics of the system are a lot more complicated than that. It’s actually really ingenious. There are multiple control surfaces all over the thing. The flight dynamics are completely different between hovering/lifting and forward motion. It’s not exactly practical, but it sure is interesting. The last time I saw something that gave me this much of a nerd boner was when I was looking at animations of the torsen differential.

  3. “Helicopters are cool because they make so much noise that the earth can’t stand to be near them, providing lift.”

    Still makes more sense than “Bernoulli’s Principle” to explain lift.

    1. This is actually true, it was explained to us by some RAF guy as we stuffed ourselves into his overloaded soup dragon that “helicopters get off the groud by making such an ungodly racket and vibration the the earth actually repels them” this was later confirmed at the landing site, we had to eject most of our gear at 80 MPH from 60 ft, because apparently helicopters can’t hover or land when overloaded, I’ve kind of hated them ever since.

    1. When I was last there, there was still one partially inflated on display in the Air Museum at the Tillamook airport.

      As the first post said, neat idea, but seemed better as an idea than a product…

      I’d never heard that it had it’s roots in a DOD or DARPA project. It was definitely a bit of entertainment watching as they tried to get the project to function.
      The marketing hype being passed around by word of mouth was that they were going to revolutionize logging in the remote timber stands, eliminating the logging roads and having to truck all the way back into the difficult areas. Bundle a number of logs, and lift the whole mess out, dropping them off at a landing for the trucks to be loaded there.

      That said, it’s been just a few years since I left Tillamook, and this was all more rumor than “official” specs/capability boasting.

      1. I just vaguely remember it being on the news. That was a long time ago. I had no idea there was a museum at the airport.

        And I agree, the design seems like something rube goldberg would have come up with.

  4. “It was a mess of a class and never quite seemed to build up to a theme or a message.” So not unlike life itself. I wished i had more of such classes in stead of the ‘do this to get that’ stuff. But of course, it should be a dialog, not a lecture

    1. Some sources say they got one of them… only it’s a big blocky triangle, a tri-rotor if you will, super quiet rotors, but also filled with helium… and the lights…. well they’re to stop you seeing it against the sky, maintains the luminance of the background.

  5. The big concern here is which gas do you use to fill it. Hydrogen is too flammable/explosive, Helium is a non renewable gas, meaning that once you release Helium in the atmosphere, it will escape in the outer space, and be lost forever. Helium is so scarce these days that the scientist capture the gas after chemical experiments, and store it for future reuse.

      1. *Zeppelin
        Blimps have no rigid superstructure inside the lift envelope.While Zeppelins have a superstructure as well as numerous lift bags instead of one single envelope.

        No hydrogen was involved in the fire. The Saturn V was unfueled at the time of the fire, the capsule interior provided all the fuel for the tragedy and contained all the fire damage.

  6. Just call it “Cargolifter” search for the term on google and see that it sounds so easy, and turns into a nightmare when looked with clear sight.

    Utmost problem: Wind drag

    To lift and lower heavy cargo safely you need a steady stay, for those you would need side thrusters similar to a ship,
    but these concepts are almost anywho only pictured with bow and/or aft thrusters.

    The side thrusters need to have extraordinary power because from the side the drag coeficient is huge = wind can act with more force, you also need to turn above the lift otherwise you shift your lift. Steer the airship along the wind not an option.

    Lifting of heavy cargo needs time, you have pulleys and many kilometers of lifting cable .. and lifting cable isn’t light (subtracts from lift capacity). And the more you lower the load the bigger then pendulum effect gets.

    Watch old flicks when the “Hindenburg” and similar air ships reached their destination and are towed down.
    Many man pulling on a rope, airship gets lifted by wind, many man are torn into the sky, some die from falling.

    Lift control near ground is terrible, because the airship also experiences ground effect.

    Watch the flick about an airship trying to dock at a sky scraper the Empire State Building(it must be laying somewhere on the internet, it was filmed from the docking port).

    This docking it was abandoned because even mild winds turned that undertaking into a huge risk.

    I worked with some people that did design the cargolifter, some yrs. after the company went bankrupt and they admit those problems.

    Sum it up, all these airship lifter ideas have a nice ring at first, but when real environment conditions are taken into account all possible advantages vanish and only disadvantages remain.

    1. The other issue that is not talked about is the problem of ballast. It is one thing to load these ships up with heavy cargo, but if there isn’t backhaul, they have to take on a lot of ballast at the other end for the trip home, and that may not be that easy to come by in the places this sort of haulage would be the best available mode.

  7. Awesome idea. I love this thing. There’s a fine line between genius and insanity? It looks like something that belongs in Futurama. But it doesn’t exactly fail safe. If the machine requires its own power to hold itself down and not float away, that seems like a large potential for total and catastrophic loss of the machine. Even submarines will bob to the surface if you blow the ballast tanks.

  8. If I make a drone that works this way and it is lighter than air, then I guess I won’t have to register it with the infamous Feds since it is lighter (measured in pounds) than the regulation thresh-hold. I could also sell them and ship them for free and demand that the post office pay me to ship it. :-)

  9. On the serious side, premanufactured house makers might be able to use this kind of technology to deliver their products. They would no longer be restricted by the need to divide up their construction into forms that could be hauled down the highway. That said, I’d be amazed if they could find a way to make that practical and the “getting a house dropped on you” joke would run rampant. The Wicked Witch of the East had better watch out. Wait!! She’s fiction. I meant the Wicked Witch of the Left. She’s real. :-)

  10. I worked for Aerolift on the Cyclocrane from 1987-89 in Tillamook OR. I had first learned about it in 1982 when I was visiting the nearby Cape Kiwanda dunes. We were camped at the KOA across the road from the airport and blimp hangars and decided to go over and see what was in them. After we looked, we still didn’t know. This thing was so huge and unlike anything we’d ever seen that we couldn’t figure it out. Shortly after I got home to Seattle my Discover magazine came in the mail with the article that you’ve linked and it all made more sense. In 1986 I was working for McDonnell-Douglas in Long Beach, CA on the propfan program, I had just become a father and decided that there were better places to raise a family. A want ad appeared in the LA Times for Aerolift, I applied and on April 1, 1987 I started work. The job was interesting, the management politics and theatrics completely overshadowed them and I quit in 1989 before the prototype was reflown. Several Youtubers have developed heavier-than-air micro-RC aircraft. One of the concepts we brainstormed but didn’t have resources to pursue was an airship with a cyclorotor at each end so the gasbag didn’t have to rotate. This would be fun to hack.

    1. Hi Nick!
      I remember that dual-cyclorotor idea- it had some very good merits, one of which reduced the flight energy required by not accel/decel the aerostat mass rotationally, along with other great effects.

      Do you recall the External Digital Ballonet? Another very cool design-mod that self-healed for most types of damage.

      I appreciated all the math you worked out for the 35-ton flight dynamics… you did an amazing job.

      Even though scaling down isn’t practical for these types of 3D lifting devices, it would still be fun to model one of these and just massively overpower it to make it work.

      I was disappointed that the 35-ton version didn’t get to fly, but at least I got to be part of the control electronics engineering and flight-data analysis and flight crew on the 2-ton proof-of-concept (Oversee the flight-by-light electronics and data-collection with my hands on the kill switch). Those two Lycoming engines dive-bombing the crew cab sounded awesome during flight!

      It was fun working with Reg & Karen Maas, Art Regan, Pete Perez, Leo Wilson, and my close friend Lars Radestam (R.I.P.), and many others in the rebuilding of the 2-Ton ship, and flying with JJ Morris, Art Crimmins, and Bill Giordano on a number of flights. On the first flight, Art Regan and I were ground-crew and riding the on-ground ballast tank (on wheels) so we could observe the lift-forces during the first test flight. It was expected to be too heavy to lift so we could get a true reading, but it turned into a brief (and exciting) flight as that incredible machine picked up the whole contraption while Art and I hitch-hiked on that flight unintentionally! JJ set us down safely once it was made known that they had some stow-aways flying with them. Ha!

      I sure enjoyed that whole project experience with Art Crimmins and Don Doolittle and Rob Crimmins, Bill Giordano, Chris Wegener, Hunter Harris, and many others. It was amazing how Rob Crimmins managed the crew for re-assembly of the aerostat and the internal ballonet- he made it look easy, but it was anything but! We had to wear slippers when working at that stage to prevent contamination and damage to the aerostat and to prevent foreign debris from getting into the interior. Great experience that I’ll never forget.

      When the project restarted again for the 35-ton version, they put together a great engineering team which included some of the original design crew such as Reg Maas and myself, but added additional very talented people such as yourself, Nick. There was a gap between that earlier success and the new 35-ton project that I don’t know much about as I had moved away with my 3 kids to another job. When I joined the 35-ton project I surely missed some of the old original faces, but got to know some new ones. Both of my tours of duty with Aerolift projects were unforgettable.

      Do you still have that awesome poster that you got from your previous employer? (Was it McDonald-Douglas? I don’t recall). Hilarious!

      -Doug Ausmus

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.