




At maximum thrust, [Negoda] and his bike — together weighing about 100kg — are able to achieve 72 km/h before the road ran out!

Much like when we featured the renegade backyard inventor Colin Furze’s turbo charger jet engine, we must emphasize great caution must be taken around jet engines. Especially those new-fangled 3D printed ones the kids are hacking together these days.

76 thoughts on “A Jet Engine On A Bike. What’s The Worst That Could Happen?

    1. You can buy a kit from this us seller. See a photo of him on his schwin bike in 1979 when he designed and built the bike jet

      J-130 Jet Engine Plans : United Nuclear – ‪http://unitednuclear.com/index.php?main_page=product_info&products_id=821‬

      1. SHUT UP!!!!!!!!
        Now the nanny-law makers are going to ruin our fun… AGAIN!

        Lets try and not translate thrust power into pedal power for our government law-making fun-breaking miserable old farts… Please ;-)

        1. I’d be surprised if this would be road-legal even below 500W. I don’t know if the Highway Code *specifically* prohibits jet engines on public roads, or specifies an acceptable exhaust temperature, but if you try and use one, it will do.

          1. My state classifies any bicycle with powered assist to be a motorized bicycle. This would not be legal as it can exceed 25mph.

            Also, doing 45mph on a mountain bike with such a steep fork angle is pretty stupid. That’s got to be wildly unstable. Not to mention, at speeds over about 12-15mph, the upright body position becomes a huge source of drag. There is a reason road bikes position the rider leaning forward, though it is also for comfort on long distances.

    1. Errm… yeah. He should be considering motorcycle leathers at those speeds.

      Last time I did 70km/hr (according to GPS) on a bicycle… I was significantly better equipped! My overalls were poly cotton which wouldn’t have protected me much, but at least my skin was less exposed, and I was wearing a motorcycle helmet (albeit a cheap one).

      That said, I remember I had a bit of extra load in the back. My run was down and up a steep saddle (Greer Street, Bardon here in Brisbane if anyone is wondering), and it was about where I hit the bottom of that saddle is when I noticed 70km/hr flash up, and shortly after, CRUNCH wobble wobble wobble… the bottom of the pannier rack gave way!

      I pulled over, saw the damage, then quietly (since it was about 5AM) said a few words before shoring everything up best I could, and gingerly riding the remaining 3km to my workplace. I got to work that day just fine, but had to get a lift home due to the busted rack.

      The stunt was not intentional, and not one I’d like to repeat.

        1. Just to nitpick, but one of the four died of heart attack, I wouldn’t say speed (as in: potential for a fatal crash) was the problem… and another guy got hit by a car, so it would seem that the speed of the car is more relevant.

        2. Add to any other peoples’ comments in reply to you…
          Pushbike helmets have a tonne more vulnerable spots than a motorcycle helmet… heck a BMX stunting helmet is safer and skateboard helmets cover more of the back of the head:

          Pushbike helmet issues:
          No frontal facial protection,
          Overhang on front facing lip that could snap the neck upon crashing into a bush!
          Rear has no cover and thus leaving the upper neck at risk,
          No ear protection,
          Holes due to sweating allowing sticks and other pointy objects to get through*,
          Itchy velcro that never aligns and thus always needing adjusting on a hot day**,
          I could keep going!

          * – BMX helmets have a mesh of metal to block foreign objects whilst exhausting sweat and thus are better.

          ** – This actually nearly killed me when in care:
          Tried multiple helmets and they were all just as bad.
          The itching of the sweating head with hair being literally ripped out by the Velcro caused such a distraction i nearly fell off a 40ft promenade (A concrete cliff!)….
          Who knows what jagged rocks awaited in the shallow waters below.
          I threw the helmet into the sea and the care-workers banned me from helmets (Yes they went against health&safety because it was safer than following said regulations!)

          As for motorcycle helmets BTW: Had no problems riding pillion and they’re very well padded with better full face encasement, still some possible risks of neck snapping, though the risk is obvious at motor-bike speeds (on average bikers on the major main roads are a few Mph faster than cars and here in the UK the police usually turn a blind eye as long as the speed isn’t taking the P***, also the police know that those few Mph don’t make much of a difference to life and death on a bike).

          1. Yah, when the kids in the fam got resistant about goofy bike helmets I upgraded them to “eXtrEme sports!” helmets, i.e. BMX style. Now they think they’re cool and they are better helmets.

          2. Another problem with bicycle helmets is that they don’t cover your neck. A motorcycle helmet provides much better coverage. But the advantage isn’t so much the obvious neck coverage, but how the lip hits your collarbone when the neck is slammed to the side. 21 years ago I had a get-off at about 70mph on a long sweeping curve. Right into some trees. My head was snapped to the left, and the helmet shattered my left collarbone into 13 pieces. That sounds bad, but it was very good, as the ER Dr. said, the helmet did its job and my neck wasn’t snapped like it would have been without the full helmet. He was a rider too, so I didn’t hear any s**t from him about “donorcycles” or the like… :-) For those curious, yes I still ride, the same bike (after a lot of repairs!) and have not had an accident since.

          1. I personally think it doesn’t matter what safety gear you are or aren’t wearing if you’re going to strap a home made jet engine to a push bike.
            The best bit being that the term “push” bike is at least accurate.

      1. Infantile is how we roll around here. Why be a boring old fart when there are so many interesting new things to try?
        Oh, and for the record I’m in my mid 40s.
        Carry on.

  1. I have HTML5 stopper, and a flashblocker – and ‘click-to-play’ enabled on my browser – yet the ^&#@$ video still plays by itself when this article is brought up ! What sort of trick is being used to bypass the blocks ??

    No mention of the brand ? (obviously not a JetCat), maybe a Wren ?

        1. Much worse? they don’t have sound, I think that alone disqualifies them from being called much worse.
          Not that I’m a GIF fan though. But I have a key combination (through extension) to stop them looping and can easily block any specific one.

          1. Much worse in terms of bandwidth consumption. GIFs really weren’t intended to be feature videos, and this is apparent in the size of them.

            I did try using a GIF once for one of my projects to documented something that needed animations, as at the time, I had no way of hosting a video. While I was able to pack the size down somewhat by sacrificing some resolution and frame rate, it was far from optimal (2.2MB for a 320×240 pixel video at I think 12fps) due to the way frames are encoded (much the same as M-JPEG: whole copies of frames with no deltas between key frames).

          2. Back in the day, when people cared about image sizes and 56k bandwidth, tools could make animated gifs quite small in comparison with other options like realmedia video wmv etc….. nowadays I suppose they don’t do key frames with differences but full res frame for each frame.

        2. @[]

          I agree.

          A multi-frame gif is not at all suited to panning images. A .swf or .flv or anything like that would be better.

          To explain –

          A single frame gif contains a color palette size attributes and then compressed pixel data

          A multi-frame gif has many of the above blocks which also include time delays and an offset value. (time delays are separate blocks).

          Because there is an offset value, width and height attributes, a frame can be used to update a smaller block of the previous image result if the rest of the image has not changed. The lower the color depth (for most animations) the greater the chance that pixels don’t change in a still background.

          So multi-frame gifs are only useful for movie type animations where the background is stable and fixed and at low color depths. A panning image is quite the opposite to this.

  2. @James Hobson: Uhm…you might want to look up how jet engines work. Specifically after writing this:
    “A LiPo battery is the engine’s power source”

    That’s not how this works. That’s not how any of it works. Just…think about it for a sec, how can something that is powered by electricity produce a 1m long flame out of the exhaust side?

    1. LOL bless the absent edit function for we may enjoy this gem for all eternity…

      One: how do you suppose it fires, magic pixies or spark ignition?
      Two: Fuel pumps are generally considered desirable for fuel injection against combustion chamber pressure.
      Three: They can be much easier to start if you get the turbine spinning at a decent speed to get some air movement first.

      1. Yeah, yeah, i know, some form of electricity is required to make an engine run.

        But it’s not the power source of the engine. Plus jet engines don’t need a constant supply of spark, just for a short time when starting the thing.

        1. Pulse jets will require a constant spark.

          “We” started J79’s with bleed air from an auxiliary power cart (-60), but some aircraft like T-33’s could start themselves (I learned that the hard way…).

          1. Pulse jets can work without a constant spark. If it is well designed the combustion will never stop, even in the absence of an ignition source. Still, better to have one, otherwise if you miss one pulse its over.

  3. He actually used a real mountain bike with full suspension, so this may be safer than most engine + biie mods. Lots of people use cheap bikes and then wonder why the head tube broke at 60 mph.

      1. I had a Raleigh frame that would rattle like a paper plane in a tornado* storm at 20 Mph on moderately rough terrain or above 25Mph on normal tarmac.

        * Ok exaggeration, however it was quite serious….
        One day I had a crash and some welding broke on the rods connecting the seatpost to the rear axle mount and I considered it written off.

        1. I did about 40km/h downhill on a bicycle with a step-through frame. That was scary (yes, it did start oscillating at about 35). No, it did not have proper brakes. As I am writing this – no crash, and everything survived, but well. I would not repeat that.

          1. Come to think of it, I have not experienced this on a bike with front suspension. I don’t know if the extra damping stops oscillation build up, or they are more careful with castor angles on newer bikes, or that I just haven’t been downhill fast enough on one yet. That latter could be true as in my current environs there’s not many so big hills that it’s wise to get up high speeds on, too many turnoffs, a vehicle may turn across you.

          2. When we were kids, we rode downhill with out stomachs on the seat and our legs straight behind us to minimize drag. Had no idea how fast we went, but looking back its amazing we survived.

            That was before bike helmets, and seats were not yet virtual ax blades in your crack.

  4. “…72 km/h, 45 mph, or 18 rods to the hogshead…”

    False. A hogshead is a measure of volume not distance (roughly 300 liters, depending on what you’re putting in it; wine, beer, tobacco etc.)

    A better obscure measurement of speed would be that the bike travels at 5726.56 perch to the ghurry, a correct (though archaic) measure of distance per unit of time equivalent to 72 km/h.

    (Perch, from the Latin “pertica” is the earlier version of “rod”, and a ghurry is 24 minutes from a medieval bowl water-clock that took 24 minutes to drain).


    1. You rounded 238.7/245.5 liter to 300 and call yourself pedantic? Tisk tisk

      Also, jet engines use an amount of fuel per second so theoretically you can throw a volume figure in the equation of final speed.

  5. I think that what is presented is the most conclusive proof ever that men did land on the Moon. A jet engine with 40 pounds of thrust could not made anything similar to a crater that some proponents of the moon hoax theory expected (e.g. www. youtube. com/watch?v=yEQNZQdJFtI ).

      1. The moon hoaxers insist that jet engines of the lunar module with the landing thrust of around 2,000 pounds should have made craters on the Moon’s surface (the linked video was one of a many).

        Mr Negoda’s video clearly showed that, even when the jet engine was directed towards the ground, no crater was produced.

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