See the full build at This information is brought to you by Bad Brothers Racing and Gary's Jet Journal Warning! If you have done everything right so far, it should look similar to the second picture below. The system will work equally well for fuel and oil systems. Alligator clips were used to connect the output terminals of the stun gun to the connections for the spark plugs. I chose to use an inexpensive stun gun to generate the sparks for the spark plugs to light the fuel inside the engine. Since my combustor will be 10 inches in length, my measurement will be taken at 9. Flame tubes welded to the end plate and intake plate, you should have something resembling the last image, minus the turbines. On the safety side can I recommend that if you cannot achieve ignition with a small amount of gas do not solve the problem with more gas — you know what will happen there! Indeed, the entire process is similar to a four-stroke cycle, but with induction, compression, ignition, expansion and exhaust taking place simultaneously.
Luckily, the internet is a fantastic resource for this sort of thing, and one can spend hours researching and watching YouTube videos on how they work, and different homemade versions that people are showing off. Calling this a working jet engine is not really an overstatement. Just take your time playing with the amount of air you put into the engine when starting an pay attention to the ignition system thats what gave me the most trouble on my engine. For the power to all of the 12 volt systems, I like to use 12 volt 7 or 12 amp hour sealed gel cell batteries such as are used in burglar alarms and battery back ups. I am able to build such things because I have a machine shop. I suppose theoretically it would be best to use smooth curves as this will reduce internal drag and turbulence inside the engine. I'm using it because it's free and available, but feel free to use your vector-graphics editor of choice.
For the oil system you will need to have a filter and an oil cooler, both of which would go in line after the pump, but before the bypass valve. Oil System A reliable supply of oil is critical to the running of the turbo, not only for lubrication but for cooling purposes. If you are contemplating a hobby in jet engines, building one of these is a good place to start as it demonstrates the basic design principles on which most gas turbines are based, that is an air compressor, a combustion chamber and a turbine. Here are a few links that may help you figure out your problem. Be safe and use hard lines. I like to use hex head cap bolts just for the look of them, but the convenience is also nice as you dont have to fidle with a regular wrench. From left to right, the hole patterns have special names and functions.
It needs to have an inlet of about 2. You are able to spend too much if you shop at specialty shops and big retailers. Step to is to provide air for the completion of combustion, and step three is to supply cooling air to lower the temperatures before the airstream comes into contact with the turbine blades. With a large pulse jet you can adjust the fuel input to alter the throttle, but the smaller the jet, the smaller the throttle range you will have available. In the photo of the exhaust manifold below, you can see the turbine flange to the right and the exhaust cap face down on the ground.
Because this isn't possible with our design, the impact angle will be slightly wider. Deflagration: This is the proper technical term for the type of explosions inside a running pulse jet. Even the smaller model jet engines are not cheap - and that's on top of the cost of the jet itself, the radio gear and all the other necessary accessories. Also if your Jet is small it will only have limited throttle range in comparison to a larger one. So you look like you know a little. This chamber also contained a tiny homemade spark plug. If you are using a water cooled turbo it is not neccesary to use the water jacket at all, and nothing need be hooked to these ports.
You can add more holes for more injectors if you like, as this is a personal preference. Flare on Intake or Tailpipe : An important action of the intake and tailpipe is to acquire outdoor air as rapidly as possible once the engine interior pressure starts to drop in each cycle. Some communities have strict noise ordinances, and you can expect to get into trouble if you violate it with your engine. Yes that could be the problem. As the turbine increases speed the characteristic jet whine will be heard and the engine will self sustain. Then I can make an instructable on this!!! No I take that back, I was looking for a jet engine used.
Does it get destroyed with the combustion? I just performed the first round of testing, and didn't exactly get the results I wanted. The golden rule here is the bigger the better. To read more about my AiR experience, feel free to check out my forum post here: Testing was difficult to actually do. Fuel And Ignition System This engine will initially be run on propane gas which makes the fuel delivery system relatively simple. This was largely made up as I went along, and so I'd advice looking at the pictures. Place tack welds on 4 sides of the rings, and allow to cool.
Once the cut is made and cleaned up, use the flap disc to bevel the outside edges of both ends of the tubing just a bit to get good weld penetration. This step is really not neccesary, as anyone with decent drawing skills can sketch out the design on the back of an envelope rather quickly. It will only be useful if you would like to supply a flow of water for cooling the turbo upon shutdown. Start by bolting the turbine flange and end cap assembly the exhaust manifold to your turbo. Plain steel engines can throw sparks occasionally while running—they come out like little white-hot bullets—so make sure you're not going to cause a grass fire behind your engine. There are also a few warnings in the comments of some of the more potentially dangerous projects. Higher Overall Pressure Ratio designs often have two concentric shafts, to improve compressor stability during engine throttle movements.
This project as mildly successful. The Pressure buildup inside will force the gasses out of the hole. The exhaust turbine goes inside of that housing. The size and placement of the holes is a mathmatical equation at best and a logistical nightmare at worst. Ebay is the way to go here, as you can really save some money. In my case, I sized it to the same dimensions as the entrance to the turbine scroll on the turbo.
Step 1 First thing first; you need the files in order to print out the parts. Your longest exauhst looks like it may be too thin. If it is a bit too long then your jet should still run, but if too short then it wont be able to self sustain the fuel ignition. Fortunately, the same type of pump can be used for both. However I need to create a spark? The finely machined tuning slides on these instuments may also be great for adjusting your effective pressure pulse frequency pipe resonance along with your fuel injector flow, to extend throttle range. Keep In mind I will have a bearing on each side. For my oil system I use Castrol fully synthetic 5w20 right now.