Add a Jet Engine to Your Project

Intro: Add a Jet Engine to Your Project

So you want to add a jet engine to your project. Naturally. Who wouldn't? After several popular youtube videos have gone viral showing jet engines attached to bicycles, canoes, and even someone rollerskating with a jetpack Wile E. Coyote style (surprise: it's me!)... you start to wonder... what else could I attach a jet engine to?

It's a dangerous hobby, and I'm suggesting that you do not attempt any of these things, but if you are absolutely determined to do this, it's better for you to have the following safety info than to not have it.

I'm the rollerskating jetpack guy, here to share my safety secrets with the curious and bold. Want to know how to buy a jet engine, handle jet fuel, and how to think about safety? Read on, adventurers!

STEP 1: Decide How Much Thrust You Need

Before you can buy a jet engine, you need to know what size to get. Jets are sized by how much thrust (push force) they produce.

I recommend buying a spring scale, and use it to pull your go-kart, canoe, or whatever you want to attach this to. If you will ultimately be sitting in the go-kart (etc) then sit in it and have a friend pull you, while watching the spring scale to see how much force it takes to get moving.

How much did it read? Ten pounds? Fifty pounds? Write that down. This is the minimum jet engine thrust you should be looking for in the next step.

STEP 2: Buy Your Jet Engine

There are several companies manufacturing small jet engines for use in radio-controlled model aircrafts. Swiwin, JetCat, and KingTech are just a few of the top names.

The main things to look for are:

1. Thrust - does the jet engine have enough thrust to move your contraption? Thrust is often measured in kilograms, so multiply by 2.2 to find the force in pounds.

2. Fuel Types - depending on the model, your jet engine might run on kerosene, diesel, and/or jet fuel. Generally diesel is safer to handle, while jet fuel will produce the most thrust.

3. Auto Start - some jet engines you'll need to start using air power or propane before you can start burning your primary fuel. These are slightly annoying to deal with and I highly recommend buying a jet engine that has an electric starter motor, which is often advertised as "auto start"

For my project I bought a Swiwin SW300B which has 30 kilograms (66 pounds) of thrust, uses any fuel type, and has auto start built in. It's a great jet and I didn't have any problems using this.

Before moving on to the next step, read the manual several times until you really understand how to operate the jet engine.

STEP 3: Buy Some Jet Fuel

Your jet engine may be able to run on several kinds of fuel, but for me the most fun comes from jet fuel. Think about telling your friends that you're going to buy jet fuel. It sounds cool, right?

So here I'm going to share a little secret. Jet fuel is nothing more than kerosene that's been refined a little more. It sounds dangerous, but fire safety experts will tell you that gasoline is much more dangerous because it has a higher vapor pressure and lower flash point.

Let's say you do want to get jet fuel. Buy a blue container that's designed to hold kerosene. I recommend a 5 gallon Scepter SmartControl container because in my experience their safety spout leads to the fewest spills. Use a permanent marker to label it "Jet A-1" so that you don't confuse this for any other fuel.

The jet engine pump nozzle is too big to fit into your jet fuel container, so you're going to need to also buy a funnel or a wide-mouth can with a flexible spout. I highly recommend this 4-quart galvanized measuring can with a flexible spout.

Search online for private airports near you, and call them to find one with a self-service jet fuel pump. These pumps are much more complicated than the gas pump for your car. Watch this video several times and mentally prepare yourself for using all the knobs and levers before going to the airport.

Dispense your fuel into your measuring can, and then pour that into your kerosene container. Be careful not to smoke or cause any sparks during the process. Be careful not to spill any jet fuel. If you spill a few drops, don't worry - it will evaporate. If you spill a lot, you will need to use the spill kit which should be nearby.

Finally, buy some jet turbine oil and use a measuring funnel to add the correct amount (according to your jet engine's user manual) to your jet fuel.

Bonus Tips:

1) If the credit card machine asks for your "tail number" leave this blank and wait or hit enter to get to the next screen. Do not worry about the ground strap, you have nothing to connect it to.

STEP 4: Test Your Jet Engine

Before you attach your jet engine to your final project, I highly recommend building a quick test stand so you can practice operating the jet and get familiar with it. I made mine out of steel but you can also use wood. The nozzle gets very hot but the mounting bracket should stay fairly cool. Do not stand behind the jet!

You'll find that as the jet builds speed, the combustion becomes so efficient that it's invisible. Don't let that lull you into a false sense of security. The jet stream is incredibly hot! If you put your hand in the jet stream for even a moment you will get a very bad burn that will probably require you to go to the hospital. Your jet engine user manual will tell you the danger zone behind the jet engine. Don't allow any person, pet, or cherished object to enter the danger zone, no matter how excited this Kenny Logins song may get you.

STEP 5: How to Not Get Burned

The primary burn danger comes from the jet stream. Be very, very careful not to let anything enter the jet stream exiting the nozzle. Think about how you will prevent your helpers or audience from coming into contact with the jet stream. Will you use caution tape, safety barricades, or something else? Have a plan and stick to it.

The secondary burn danger comes from touching the nozzle while it's still hot. Even if it's not glowing red, it may be very hot. Give it at least 5 minutes to cool down after each run before you think about touching the nozzle or the metal body of the jet engine.

Make sure to have a fire blanket and a fire extinguisher nearby. I recommend a nomex fire blanket for its burn resistant characteristics and a CO2 fire extinguisher because it won't ruin your jet engine like the ABC powder type extinguishers will.

You may want to wear a fireproof underlayer like racecar drivers wear, such as this set. Over that I would recommend dense cotton clothing like denim, and avoid fabrics like polyester that do not self-extinguish.

I recommend starting with full-length clothing that covers as much skin as possible. If the flame somehow briefly touches the clothing, it will really help prevent you from getting a severe burn.

STEP 6: Attach Your Jet Engine to Your Project

Consider these important safety topics as you design and build your project around your jet engine:

1. Use a roll cage - If your jet engine crashes into something, the hardened metal turbine blades that were spinning at nearly 100,000 RPM can come loose and fly out, potentially injuring you or a bystander. Build a steel cage around the jet engine to take the force of any impact that may happen and save your jet engine from destroying itself and potentially injuring someone.

2. Protect yourself from the inlet - The inlet of the jet engine is going to be sucking in an incredible amount of air. Make sure the operator's hair and clothing can't get near it.

3. Use a heat shield - The fire emits a lot of thermal infrared heat. This is the radiant heat that makes your skin feel warm when you are near a campfire. Aluminum will reflect nearly all of this heat, even if it's a very thin layer of aluminum. On my jetpack you'll notice an aluminum heat shield after the nozzle to reflect this heat away from my body.

4. Use lots of failsafes - Think about what will happen if you crash. Will the jet stop automatically? It will if you use a "deadman" switch, which is any switch that turns things off if it is released. What happens if you start to catch fire but you can't see it because the jet engine is behind you? If you have a friend with an emergency remote stop that operates over a radio link, your friend can turn off the jet remotely when they see that happen. What happens if that remote stop is out of range? If your system automatically stops if it's not receiving a signal, then that's a fail safe. What happens if your controls come loose? Use pull-up resistors in your electronics or some other feature that will turn things off if the controls come off. What happens if the code in your microcontroller fails for some reason? If your "deadman" switch cuts the power to the microcontroller, then your code does not represent a single point of failure - you can disable the jet even if the microcontroller freezes up.

STEP 7: Have Fun Safely

Enjoy your new jet-powered project!

Jet engines are incredibly loud, so always wear earplugs. Also wear lots of protective gear - including a full-face helmet to protect your face and teeth in the even of a crash.

Over time as you become more comfortable operating your jet engine, it's easy to forget how dangerous it can be. Don't disable any safety mechanisms, and always make sure to have several helpers on site to hold the fire extinguisher, remote stop, and to help as well as having fun.

Comments

[CraftyChameleon07]

Regarding fuel-- Diesel and Jet A / JP8 etc are functionally the same for most of these applications. 'Jet Fuel' is just diesel with anti-ice and anti-microbial additives but for almost all low-altitude applications diesel will serve just as well. That's why the Germans went so hard into Jet tech in WW2-- it allowed them to run high performance aircraft on diesel when avgas was unavailable due to allied bombing/ blockades.
DO NOT RUN AVGAS in a jet engine. AVGAS has a much higher temperature of combustion than diesel/jet fuel. This means it releases it's energy much more explosively and efficiently if the pressures can be contained. It's a substantially more explosive and dangerous fuel. Notably, AVGAS vapors can explode, quite readily, where diesel's temp of vaporization and flashpoint are much higher and safer to tinker with. If you think in terms of octane diesel is ~72 octane, where almost all US AVGAS is 110 octane, so you can see it's a radically more explosive and volatile fuel.

[IanCharnas]

Hi and thank you for the comment! I agree that AVGAS (as well as gasoline) is more dangerous than kerosene, jet fuel, or diesel, and should not be put into a jet engine. There is one correction I'd like to make though. Jet A and JP8 are based on kerosene, not diesel. I believe Instructables will let you edit your comment if you'd like. If you do that, I'll delete this reply to eliminate any confusion. Take care and thank you.

Source: https://www.oiltanking.com/en/news-info/glossary/d...

[CraftyChameleon07]

Kerosene is itself a diesel fuel, as diesel is a broad term for high carbon number, low volatility (C30+) fuels. The specific type of diesel used as feedstock for JP8 etc is Kerosene, as you point out, but it is still diesel. If using a non-kerosene diesel, like F76 or ULS #2, there might be a slight risk of a high interstage turbine temp, but I doubt it at ground level. Would be very unlikely in a non-aviation, below 10k' environment.

[IanCharnas]

Good point! Indeed, Rudolf Diesel originally ran his eponymous engine on kerosene and/or petrol.

[SaintoKillers]

Great job man and thanks for a very entertaining, yet informative, video. If you went through the welding program and was able to actually weld at the end of that one week course, Bravo to you! Please don’t think I’m being sarcastic, for that is not my intent. I worked as a welder/ fabricator for just over 10 years and I’m very familiar with what it takes to weld correctly. With your enthusiasm and welding skill; “The possibilities of opportunities will only be limited by that of one’s ingenuity.”(me 2021) . Best of luck forward while occasionally glancing backwards to remind us, of not only how far we’ve come, but for those we met along the way. First goal everyday is to have fun

[IanCharnas]

Hey thank you for the super kind words! The 1-week intro course gave us the basics in stick, MIG, and TIG. I was careful on this project though to choose things that would be pretty easy to weld. 1/8" and 1/16" mild steel is on the easier side as you know from your experience. Welding can fill a lifetime of experience and I know I have only scratched the surface - but it's nice to be able to do at least some basic welding like basic T-joints and lap joints on mild steel. Someone like you with 10 years of welding experience could do a lot more than I could. Anyways - I appreciate your positive and encouraging comment!

[Sewphia_Makes]

I'm learning roller derby, and for some reason im just imagining someone showing up to a bout with this on lol.

[IanCharnas]

Hehe. There's nothing in the rules that says no jetpacks :-)

[K-jyst]

Ian, can you say anything about thrust vector vs human cg? Aka, "why doesn't the jet point straight backwards from your spine? And does that much thrust complicate keeping your balance while skating?

[IanCharnas]

Hey great question! A good skater will bend at the hips and knees and get low in order to maintain balance while going fast. When I was designing this, I tried to find a good angle between the jet and the back so that once you were in "racing" position the jet would be mostly horizontal. However it's nice to have at least a little vertical force because it relieves some of the weight of the jetpack (it weighs about 20-25 pounds).

[K-jyst]

Glad to hear Ian's failsafe thinking. It is powerful and to the point, enabled his whole adventure, and it's the first thing practical people want to drop...

[Pa1963]

I tried to buy avgas from a local municipal airport, but the person on the phone refused to sell it to me. I don't know if he could actually do this, or he just didn't want to be bothered. Probably a hassle to sell just a couple of gallons of fuel.
Anyhow, nice 'ible. Glad there's nut jobs like you willing to risk torching your own behind, just to entertain the rest of us. See you at the Darwin Awards!

[JayH25]

well, after reading this, I'm pretty sure you just need to ask for pixie-dust or unicorn farts -- the Jet Fuel is just for bravado...

This instructable is laugable, but hey, 'struct-on, brother!

[darrel999]

Airports are legally forbidden from selling aircraft fuel for any use except in aircraft. You may be able to get them to make an exception for a small amount of fuel if you strike up a friendly conversation with the attendant and are not perceived to be a "Hold my beer and watch this!" kind of person. I am not saying you came across that way. But if they sell you the fuel they probably have some liability if something goes wrong with its use.

[IanCharnas]

Interesting and thank you for commenting here. My understanding is there is no regulation at the state (Ohio) or federal (FAA) level mandating that airports only sell fuel for use in aircraft. There is an RC jet airplane community that would be very disappointed if they could no longer purchase jet fuel.

Of course, I am willing to admit if I am wrong here - if so, can you provide a link to the FAA rule or ORC (Ohio revised code) section that prohibits airports from selling jet fuel for any use except in an aircraft?

[ScottS506]

I'm glad they put this on instructables, now I can use my own personal metal fabrication shop and welding shop to build one for myself, since I just happened to have a jet engine in my closet.

[IanCharnas]

Hahaha yes admittedly a jet engine is not something most people keep in their junk drawer. Hopefully people still find this interesting :-)

[ScottS506]

Yes, it was extremely entertaining. Thankfully you were not injured.

[楊老師楊]

Interesting & funny !
I want to test an jet engine but it is too expensive..............may be DIY one some other day

[louislavoie1128]

I build and test jet engines for a living. I would not call what you're doing "safe". This is not the movies and you're not the rocketeer. I've seen first hand what happens when a turbine come apart. Having this strapped to you back would ensure death. Your little metal cage won't help you. We make turbine containment from titanium and when we do destructive testing there's an inch of solid steel and a foot of concrete between us and the engine. Be careful.