Intro: Pulse Jet Powered RC Ice Racer!
Normal remote control cars, planes, boats and RC whatever are boring. This Instructable is on how to make a pulse jet powered ice racer! This is a very unique loud and dangerous RC vehicle that you could build in about one day with the right materials and tools and a little experience with pulse jets.
My brother and I both have a great interest in welding and fun dangerous stuff. So a few years ago when we got our first welder and we were just learning to weld, we thought it would be a fun and simple first project to make a small model sized pulse jet engine. That was simple and fun. We then thought what could we do next that would be something like this? Of course we thought bigger is better, especially if its remote controlled and thats what lead us to creating the Pulse Jet powered Ice Racer! Here is the final video of it running!
What is a pulse jet? Well, it is the easiest type of engine that you can make in just a matter of hours and they have no moving parts (the valveless type). They are extremely loud (140+ db) and glow red hot and can run on any type of fuel. Here is a link to a wiki page explaining more about them better than I can. Also, this is the design of the engine we used.
If your going to do this make sure you do it during the day and on a larger lake not in a city because these things are really fricken loud. Running pulse jets at night pisses off the neighbors as you can hear it from miles away...
Let me know if I should clear up some of the steps as it may be just a little confusing.
Here are my answers for the Make to Learn Youth Contest - Most answers regarding how to make it are already throughout the instructable
What did I make?: I made a remote control ice racer that uses a pulse jet to produce the thrust to move and remote control parts from an old RC car. I have a link above as to how a pulse jet works but basically if you have the correct dimensions it will stay lit and continue on its cycle, thus the name pulse jet as it has continuous explosions that create a distinct buzzing sound. The main tool that I used was a MIG welder to weld together the metal frame and pulse jet. I have been welding since I was 13 and I am currently 15.
How did I make it?: My brother and I got the idea from a project we did 5 or more years ago. That project was also an RC ice racer but much smaller and used a motor and propeller from an old plane. A few years ago when we got the welder and were thinking of project we decided to make pulse jets since they were simple enough. That then lead to bigger pulse jets, which then this year led to us making something that actually moves out of one. My brother and I worked on this project for 3 days. At the start we had a rough idea as to what we were going to do but most of our ideas changed as we progressed. Mostly just the design of the frame changed. The front steering was mostly just guess and check.
Where did you make it?: We made it in our garage workshop at home and took it to a near by lake to test it out. It connected with other activities in our lives because we had made the pulse jet a few months before so we finally put it to good use!
What did I learn?: The biggest challenge we faced was setting up the steering and servo. That just took some time and finess to get into the right spot and to make sure it all lined up. I am immensely proud of how the whole thing turned out! We weren't expecting much, but it was above and beyond what we expected. Plus, I am proud of how well this instructable did! If I did it again I think I would change the placement of the tank to the front area and have it sit upright and change the design of the frame and make it narrower to save excess weight. Also, if I had a lot of time, I would make a big pulse jet because the bigger the better! (and faster)
Step 1: Design
It took quite some time to decide on what the design should be and where to place the pulse jet and propane tank. We ended up laying the metal pieces out on the ground to get a rough idea of what it should look like. Almost all of the angles and lengths we kind of just guessed on and would round off to the nearest whole number. Surprisingly though, everything turned out perfect and symmetrical! Although you may criticize us for not measuring it worked out just fine and didn't need to be exact, it wouldn't have been much of a big deal if it was off by a tiny amount. Additionally, we were in kind of a rush to complete it as my brother was going back to college from winter break in just a few days.
What took a long time, was we had to figure out where to stick the propane tank, as we wanted the pulse jet to run down the middle of the frame and we didn't want the tank to sit on the front and put a ton of weight on the control arm and front skate. Plus, we just wanted it to look as cool as it sounds!
Step 2: Materials and Tools
This is a really fun and relatively easy and cheap project if you have the right materials, tools and knowledge (if you can weld that'll help a lot). Also, we had made the pulse jet a few months before so I won't be explaining how to make it in this Instructable (fairly easy to make though).
30+ feet of 1/2in x 11ga steel bars/strips
2 pairs of old skates
32in x 16in 20ga steel sheet metal
1/4in steel rod
Lock screw stoppers
Pulse Jet Materials:
Small 10-15 pound propane tank
Rubber grill hosing
Electronics (harvested from a old RC car):
MIG or TIG welder
Chop saw with metal cut off disc
Hand held grinder
The usual hand held tools
The total cost of everything was probably around $30, although we already had most of the materials besides the metal.
Step 3: Skates
The first thing we had to do was get two pairs of skates and cut off their blades. Getting the skates was fairly simple especially in the winter, just ask around for old skates from your neighbors and they are more than willing to give them to you probably. Although they tend to get confused when they ask what your doing with them, and you tell them your welding them to a jet engine...
One of the hardest things we had to do for this whole project was to get the damn blades off the actual skate.. Now cutting and grinding off the blade on the old skate was a piece of cake, but on the newer skate it was practically fused to the base of the boot with plastic.. We ended up having to basically melt that plastic and pry it out, making sure not to bend the blade.
Step 4: Welding and Cutting the Frame
The metal strips that we bought were all 48 inches long, so that help quite a bit and you'll see why. The first thing we did for the frame was take three full strips and create the triangular shape to the frame. We did this by making an isosceles triangle with the two sides being 48 inches long and the base measuring 36 inches, with 6 inches coming off of both ends of the base for the back skate mounts (hopefully that makes sense so far, if not look at the first 3 photos). This was the only time we really measured anything, the rest of the time we just laid it out, marked it, then cut.
Next for the frame, we created the middle X part for support. We did this by cutting two 28 inch pieces, welding one in place, and cutting the other piece in half to form the X (see photos 4 and 5).
The next step for the frame was to finish off the back skate mounts. This was accomplished by lining up and extending the bottom part of the X to line up with a 4 inch piece coming off of the base of the triangle. Once this was all welded together, the frame was complete (see photos 6 - 10).
Step 5: Mounting the Back Skates
Mounting the back skates to the frame was fairly simple. Although you have to make sure that the are completely straight up and down and not crooked so we used a level and a flat surface. My brother and I decided we wanted the frame to be as close to the ground as possible but to also ride high enough to go over a few inches of snow. We went with making the supports that hold the skates to the frame 5 inches tall. Making a few marks and couple welds this part of the build was finished in just a couple minutes.
Step 6: Mounting the Pulse Jet and Propane Tank
Mounting the pulse jet to the frame was fairly simple. Since it was made out of metal (duh) we just welded it directly to the frame. We had a hard time deciding whether or not to mount it off center to balance out with the propane tank but we thought that would look dumb. To mount it we cut small pieces of metal to hold it in place and to get it to be level.
For the propane tank we thought it would be best to mount it directly to the left of the pulse jet, leaving a few inches of space as the pulse jet gets extremely hot.We also had to mount the tank on its side otherwise we thought it might get to top heavy. Although, it probably wasn't the best idea to mount the tank on its side because it probably messed with the flow of the propane and pressure.
Step 7: The Front Skate
For the front control skate we took a 8 inch metal rod, metal collar, two lock screw stoppers (I don't know the real name of them), and the actual skate. What we did was weld the metal collar vertically into the front angle of the frame. Then we welded the metal rod to the skate (making sure it was vertical). Next one of the lock screw stoppers was place on the rod so that the front would sit about 5 inches off the ground. After that the top lock screw stopper was put it place once the rod on the skate was placed in the vertical metal collar. (Look at the pictures, they describe what we did a lot better than I could). Once it was a little greased up it turned perfectly and didn't bind up.
Step 8: Electronics and Propane Hose
All of the electronics we used on this project were safely harvested from an old RC car, so the car would still work if we put them back in. What we did was pretty straight forward. We just had to add a sheet of metal to mount the electronics on and a simple heat shield to protect them from the combustion chamber of the pulse jet. The only difficult part of this step was to find out where the propane hose would go, other than that it was all pretty easy. I'll let the pictures do most of the talking again, but ask questions if your confused.
Step 9: Finished and First Test!
We finally got this done in just a matter of 2 days working almost non-stop in 10 degree weather, but it was definitely worth it! When it was finally done it weighed a bit more than we expected but actually worked great! If it were to go on pure ice it would easily go 20+ mph and through about 2 inches of rough snow it went about 10+ mph, so it worked great according to our standards. The one problem we experienced was the fuel line freezing up and loosing pressure do to the outside cold and the extreme cold of the gases.
More videos soon, but here is one of the test on pure ice that I posted on the first slide.
Hope you enjoyed it! Comment if you have any questions!