Propeller Backpack for Lazy Skiers

At first glance, it looks eerily similar to Inspector Gadget’s Propeller Cap, except it’s a backpack. [Samm Sheperd] built a Propeller Backpack (video, embedded after the break) which started off as a fun project but almost ended up setting him on fire.

Finding himself snowed in during a spell of cold weather, he found enough spare RC and ‘copter parts to put his crazy idea in action. He built a wooden frame, fixed the big Rimfire 50CC outrunner motor and prop to it, slapped on a battery pack and ESC, and zip-tied it all on to the carcass of an old backpack.

Remote control in hand, and donning a pair of Ski’s, he did a few successful trial runs. It looks pretty exciting watching him zip by in the snowy wilderness. Well, winter passed by, and he soon found himself in sunny California. The Ski’s gave way to a bike, and a local airfield served as a test track. He even manages to put in some exciting runs on the beach. But the 10S 4000 mAH batteries seem to be a tad underpowered to his liking, and the motor could do with a larger propeller. He managed to source a 12S 10,000 mAH battery pack, but that promptly blew out his Aerostar ESC during the very first static trial.

He then decided to rebuild it from ground up. A ten week welding course that he took to gain some college credits proved quite handy. He built a new TiG welded Aluminium frame which was stronger and more lightweight than the earlier wooden one. He even thoughtfully added a propeller safety guard after some of his followers got worried, although it doesn’t look very effective to us. A bigger propeller was added and the old burnt out ESC was replaced with a new one. It was time for another static trial before heading out in to the wide open snow again. And that’s when things immediately went south. [Samm] was completely unaware as the new ESC gloriously burst in to flames (8:00 into the third video), and it took a while for him to realize why his video recording friend was screaming at him. Check out the three part video series after the break to follow the story of this hack. For a bonus, check out the 90 year old gent who stops by for a chat on planes and flying (8:25 in the third video).

But [Samm] isn’t letting this setback pin him down. He’s promised to take this to a logical finish and build a reliable, functional Propeller Backpack some time soon. This isn’t his first rodeo building oddball hacks. Check out his experiment on Flying Planes With Squirrel Cages.

We seem to be catching a wave of wind-powered transportation hacks these days. Hackaday’s own [James Hobson] spent time in December on a similar, arguably safer, concept. He attached ducted fans to the back of a snowboard. We like this choice since flailing limbs won’t get caught in these types of fans.

 

 

Thanks [Itay], for the tip.

21 thoughts on “Propeller Backpack for Lazy Skiers

  1. When my daughter was 11 I made one for her with a chainsaw engine and a 16″ APC prop. She used it with rollerblades on no stinkin’ amputation guard. It sounded like a Spitfire flyover every time she passed me on the bike lane.

    1. “A Troll! Quick Roberts, fetch my shotgun!”

      “Ahem… If I might be so bold as to venture an opinion my Lord. Trolls are notoriously difficult to kill. Shooting it may simply annoy the beast.”

      “Damn and Blast! You’re right of course. I suppose we’ll just have to put up with it’s nonsense.”

      “I’m afraid so my Lord.”

        1. Tore Lund

          Douglas: [Douglas gets electrocuted] HELLS TEETH! They’re just cars! I’m not aroused! God DAMN these electric sex pants!
          Douglas: [to Moss] You there, computer man. Fix my pants.
          Moss: I beg your pardon.
          Douglas: Pull down my trousers and do your job.
          Douglas: God-damn these electric sex pants!

          1. I accept defeat, I can’t decide if you are pulling my leg, however my original somewhat anecdotal comment is a true story. The engine was bolted to a piece of plywood with backpack straps stapled on for wearability. She had a string as throttle and a wall switch taped to one strap as kill switch. Thrust was between 3 and 5 pounds and she went around 15 mph. (she used plenty of hair pins).

    1. At least a couple of hacks here

      https://en.wikipedia.org/wiki/John_Denver
      On October 12, 1997, Denver was killed when his experimental Adrian Davis Long-EZ plane, aircraft registration number N555JD, crashed into Monterey Bay near Pacific Grove, California, while making a series of touch-and-go landings at the nearby Monterey Peninsula Airport.[38] The National Transportation Safety Board’s (NTSB) accident ID is LAX98FA008.[39] Denver was the only occupant of the aircraft. The crash seriously disfigured Denver’s head and body, making identification impossible by dental records, and his fingerprints were used to confirm that the fallen pilot was the singer.[40][41]

      A pilot with over 2,700 hours of experience, Denver had pilot ratings for single-engine land and sea, multi-engine land, glider, and instrument. He also held a type rating in his Learjet. He had recently purchased the Long-EZ aircraft (which was made by someone else from a kit)[42] and had taken a half-hour checkout flight with the aircraft the day before the accident.[43][44]

      Denver was not legally permitted to fly at the time of the accident. In previous years, Denver had a number of drunk driving arrests.[45] In 1996, nearly a year before the accident, the Federal Aviation Administration learned that Denver had failed to maintain sobriety by failing to refrain entirely from alcohol, and was compelled to revoke his medical certification.[35][36] However, the accident was not influenced by alcohol use, as an autopsy found no sign of alcohol or other drugs in Denver’s body.[46]

      Post-accident investigation by the NTSB showed that the leading cause of the accident was Denver’s inability to switch fuel tanks during flight. The quantity of fuel had been depleted during the plane’s transfer to Monterey and in several brief practice takeoffs and landings Denver performed at the airport immediately prior to the final flight. His newly purchased experimental Rutan had an unusual fuel selector valve handle configuration. Intended by the plane’s designer to be located between the pilot’s legs, the builder instead had placed the fuel selector behind the pilot’s left shoulder, with the fuel gauge also behind the pilot’s seat and not visible to the person at the controls.[35][36] An NTSB interview with the aircraft mechanic servicing Denver’s plane revealed that he and Denver had discussed the inaccessibility of the cockpit fuel selector valve handle and its resistance to being turned.[35][36]

      Before the flight, Denver and the mechanic had attempted to extend the reach of the handle, using a pair of Vise-Grip pliers.[35][36] However, this did not solve the problem, and the pilot still could not reach the handle while strapped into his seat.[35][36] NTSB investigators’ post-accident investigation showed that because of the positioning of the fuel selector valves, switching fuel tanks required the pilot to turn his body 90 degrees to reach the valve. This created a natural tendency to extend one’s right foot against the right rudder pedal to support oneself while turning in the seat, which caused the aircraft to yaw (Nose right) and pitch up.[35][36]

      The mechanic said he had remarked to Denver that the fuel sight gauges were visible only to the rear cockpit occupant. Denver had asked how much fuel was shown.[35][36] He told Denver there was “less than half in the right tank and less than a quarter in the left tank”.[35][36] He then provided Denver with an inspection mirror so he could look over his shoulder at the fuel gauges. The mirror was later recovered in the wreckage.[35][36] Denver said he would use the autopilot inflight, if necessary, to hold the airplane level while he turned the fuel selector valve.[35][36] He turned down an offer to refuel, saying he would only be flying for about an hour.[35][36]

      The NTSB interviewed 20 witnesses of Denver’s last flight. Six of them had seen the plane crash into the ocean near Point Pinos.[35][36] Four witnesses stated the aircraft was originally heading west. Five said they saw the plane in a steep bank, with four of these saying the bank was to the right (north). Twelve witnesses described seeing the aircraft in a steep nose-down descent. Witnesses estimated the plane’s altitude at 350 to 500 feet while heading toward the shoreline. Eight said that they heard a “pop” or “backfire”, accompanied by a reduction in the engine noise level just before the airplane crashed into the sea.

      In addition to Denver’s failing to refuel and his subsequent loss of control, while attempting to switch fuel tanks, the NTSB determined there were other key factors that led to the accident. Foremost among these was Denver’s inadequate transition training on this type of aircraft, and the builder’s decision to locate the fuel selector handle in a difficult to reach location.[35][36] The board issued recommendations on the requirement and enforcement of mandatory training standards for pilots operating experimental aircraft. It also emphasized the importance of mandatory ease of access to all controls, including fuel selectors and fuel gauges, in all aircraft.

  2. I see a lot of projects where “and it almost set me on fire” is a sort of humorous add-on or badge of honor. I’d like to remind everyone that occasionally such projects actually do light someone on fire and skin grafts are no fun at all.

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