Jonny69
20-05-2009, 12:03
Following on from my spudmatic gun I'll move onto my jet scooter. I built a large-ish pulsejet as part of my final year project at university. It's made from mild steel pipe and rolled sections with a 2" exhaust. It runs on propane and output is about 15lbs of thrust I think, can't remember. Naturally with a jet in the shed you need a scooter to put it on so I lengthened one of those metal kick scooters and mounted the jet on the back. This is what I ended up with:
http://www.dropfiles.net//files/319/inventions/IMG_3794.JPG
http://www.dropfiles.net//files/319/inventions/IMG_3791.JPG
Note how there's no throttle and no brake. Power is controlled by winding in the regulator which is about 5 turns from off to 4 bar of gas pressure:
http://www.dropfiles.net//files/319/inventions/IMG_3796.JPG
Noisy end where all the fire comes out:
http://www.dropfiles.net//files/319/inventions/IMG_3800.JPG
Intake, sucks the hairs off your legs:
http://www.dropfiles.net//files/319/inventions/IMG_3801.JPG
http://www.dropfiles.net//files/319/inventions/IMG_3802.JPG
http://www.dropfiles.net//files/319/inventions/IMG_3803.JPG
And as with most of my toys it folds up and neatly stashes in the corner ;)
http://www.dropfiles.net//files/319/inventions/IMG_3807.JPG
Here's a youtube video of some early testing. It's all the footage I have but the jumping camerman who starts to back off when I wind it up gives you an idea how loud it is!
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/exriWvX3_cU&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/exriWvX3_cU&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>
Running procedure is sparkplug on, gas on, shoot some air in the front with a leaf blower to start it, turn the sparkplug off and wind the gas up. At the end you see a shower of sparks fly out the front and the motor stops. This is the valves destoying themselves before I had found suitable material for them and I experimented with a tuned valveless intake for indefinite running. Short video here:
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/YUdQenRkyd8&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/YUdQenRkyd8&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>
How does it go? Well it makes a proper load of noise, glows red hot, there's fire, explosions and a real risk of getting hurt. It doesn't actually go all that fast because it doesn't have a huge amount of thrust for the weight of a person. I have ridden it and slipped off and when the weight is off the deck it tries to fly off. So consider this the mk1 and there's a mk2 in the pipeline with brakes, proper throttle control and somewhere better to stand. And a little more thrust of course ;)
http://www.dropfiles.net//files/319/inventions/IMG_3794.JPG
http://www.dropfiles.net//files/319/inventions/IMG_3791.JPG
Note how there's no throttle and no brake. Power is controlled by winding in the regulator which is about 5 turns from off to 4 bar of gas pressure:
http://www.dropfiles.net//files/319/inventions/IMG_3796.JPG
Noisy end where all the fire comes out:
http://www.dropfiles.net//files/319/inventions/IMG_3800.JPG
Intake, sucks the hairs off your legs:
http://www.dropfiles.net//files/319/inventions/IMG_3801.JPG
http://www.dropfiles.net//files/319/inventions/IMG_3802.JPG
http://www.dropfiles.net//files/319/inventions/IMG_3803.JPG
And as with most of my toys it folds up and neatly stashes in the corner ;)
http://www.dropfiles.net//files/319/inventions/IMG_3807.JPG
Here's a youtube video of some early testing. It's all the footage I have but the jumping camerman who starts to back off when I wind it up gives you an idea how loud it is!
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/exriWvX3_cU&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/exriWvX3_cU&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>
Running procedure is sparkplug on, gas on, shoot some air in the front with a leaf blower to start it, turn the sparkplug off and wind the gas up. At the end you see a shower of sparks fly out the front and the motor stops. This is the valves destoying themselves before I had found suitable material for them and I experimented with a tuned valveless intake for indefinite running. Short video here:
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/YUdQenRkyd8&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/YUdQenRkyd8&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>
How does it go? Well it makes a proper load of noise, glows red hot, there's fire, explosions and a real risk of getting hurt. It doesn't actually go all that fast because it doesn't have a huge amount of thrust for the weight of a person. I have ridden it and slipped off and when the weight is off the deck it tries to fly off. So consider this the mk1 and there's a mk2 in the pipeline with brakes, proper throttle control and somewhere better to stand. And a little more thrust of course ;)