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.

24 thoughts on “Pulse jet snowmobile, or, what Swedes do during hibernation

    1. It runs very well, but most of the test runs are stationary because we do not have the space to actually run the thing. Today we finished the first complete run on the track and are very satisfied :)

  1. “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.

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

        1. 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.

          1. 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.

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

    Which it more than makes up for in raw awesomeness!

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s