Elizabeth Helmkamp and Janelle Cammenga-Staff Writer
Because why not?
ASME fights back with pulse jet
Last year, electrical engineering majors took it upon themselves to make a rail gun. The mechanical engineers then saw their fellow future engineers’ project and, being nothing if not competitive, stepped it up this year to make a creation of their own: a pulse jet.
Put simply, a pulse jet is an engine with no moving parts. It takes in air from both ends and shoots it out both ends when the fuel explodes. This creates a vacuum that sucks in fresh air for the next explosion. The blast propels the engine forward because one tube is longer than the other, so more air is pushed through the longer tube.
The engineers built the jet “really just to see if we [could] do it and challenge ourselves. Plus, it looks cool and it makes a lot of noise, that’s always fun,” said senior Andrew Cammenga, who led the project. Nicolas Kuperus and Jesse Ewald helped with the build, and other engineers pitched in at different points in the process. They built the jet from a pre-existing design and then added their own knowledge to it.
One of the biggest problems in the process was figuring out the right ratio of compressed air to fuel the jet in order to keep the machine running.
Of course, these engineering majors did not know exactly what the problem was, so they tried everything they could think of, including switching where the compressed air was added, where the propane was added and how to keep the sparkplug lit. Partway through the process, the group discarded the sparkplug altogether in favor of a blowtorch.
At one point, on a whim, Cammenga “just stuck the blowtorch in and turned it on. [The pulse jet] started running without the compressed air.”
Figure that one out.
Cammenga’s favorite moment was when they finally got the jet working.
“We’ve got it on video with me screaming in the background,” he said.
The group plans to make a diverter for the engine, meaning they plan to turn one of the tubes so both ends face the same direction, in order to produce thrust.
After all this time and effort, what great feats can this pulse jet do?
“If we’re doing well, it generates about three pounds of force,” Cammenga said.
“In reality it’s pretty pathetic, but it’s awesome-sounding!”
Besides the concept of how the machine works, he loves the sound it makes.
“You can feel it in your chest, like when Jesse really cranks up the subs in the BJ Haan,” Cammenga said. “It’s freaking loud.”
Throughout the process, the engineers enjoyed working through the problems and seeing their creation finally work.
In regards to what he learned from the process, Cammenga said: “Sometimes insanity is doing the same thing over and over again, but sometimes doing the same thing over and over again shows you what you should change.”
He also said he learned backflow regulators are not necessary to life if you’ve got a long enough hose, but that one’s not as generally applicable to us non-engineers.
The group hopes to showcase their creation sometime in the future, but no firm date has been set.