Pulse jet snowmobile, or, what Swedes do during hibernation

jetSweden is coming out of the depths of a cold, dark winter. What better time, then, to enjoy the last few weeks of frigid temperatures, short days, and frozen lakes and rivers? That’s what Orsa Speed Weekend is all about; tearing across a frozen lake by any means necessary, including jet powered snowmobiles.

This pulse jet comes from the fruitful minds at Svarthalet Racing (Google Translation) who have put an amazing amount of work into their fuel-injected pulse jet snowmobile during these last cold winter months. They’ve even gone so far as to do some analysis regarding how much horsepower their snowmobile has. Surprisingly, it’s not much more horsepower than a small car, but that’s due to the hilarious inefficiency of pulse jets compared to more conventional engines.

This isn’t the first time we’ve seen jet powered snowmobiles build for Orsa Speed Weekend. We’ll just hope this year a few more videos will show up in our tip line.

Comments

  1. it seems it makes a lot of fire and noise but can’t actually run :-)

  2. Dax says:

    “hilarious inefficiency of pulse jets”

    As all reaction engines, their efficiency increases with speed. At a standstill, every jet engine or rocket has an efficiency of zero because a static force does no work. It’s only when the sled starts to move that the engine is doing any real work, and the notion of efficiency starts to apply.

    • Dax says:

      And for a pulsejet engine, 200 km/h is almost as good as standing still.

      • AS says:

        Yep, that’s the problem. Pulsejets are basically the ramjets inbred cousin so anything below transonic velocities is wasting most of the power.

        • Dax says:

          Pulsejet won’t work over the speed of sound, because they operate by sending a pressure wave towards the front to close the valves and create a standing wave inside the tube that operates the cycle. It needs to reflect the pressure wave back from the valves to create the vacuum that pulls in more air. Once it goes past the speed of sound, the valves would just jam open and it would work as a ramjet if it works at all. It would probably flame out well before that.

          • mental2k says:

            Out of curiosity what about valveless designs?

            Unfortunately my undergrad course had only one class on A/C engines and the lecturer took a stroke about half way through the semester, so we mainly looked at calculating efficiencies through turbofans etc.

            Intuitively it seems like there must be issues transitioning from pulse to ram jets for proper A/C applications, otherwise why would the SR-71 have turboram hybrid when a pulseram would look more logical on paper.

      • mental2k says:

        Depends on you altitude, there’s a distinct drop off in the speed of sound with altitude…

  3. Skitchin says:

    Jet moto!

  4. click says:

    It sounds so nice when you write “the last few weeks”, sadly it’s more like months until this winter is over :'(

  5. qwerty says:

    Just dont use it anywhere near a UK WWII veteran house if you don’t want to be shot.

  6. After the blizzard we got last weekend, I think this is the only reasonable solution for travelling in the show. Traction? Who needs traction?

  7. where is the movie?

  8. Måns says:

    Here is the movie from the contest (might be more movies)

  9. jaded says:

    “the hilarious inefficiency of pulse jets compared to more conventional engines.”

    Which it more than makes up for in raw awesomeness!

  10. Archibald Tuttle (@SquittersTweet) says:

    Love the sound! A bad ass beast!!

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