Engines 04

OPENING QUESTION:  We discussed yesterday the ways in which piston (propeller) driven aircraft engines were different from jet engines, and why jet engines tend to be more efficient then piston engines.

If that's the case, why aren't ALL airplaines driven by jet engines?

LEARNING GOAL FOR TODAY: I will be able to compare and contrast scramjet and ramjet engines during today's class.


  • Thurst ("forward pushing force")
  • Air Friction ("resists forward motion")
  • Lift ("Lower pressure, upward pull")
  • Weight ("downward pull")
  • Propeller ("Pulls Air")
  • TurboProp
  • Jet Engine ("Pulls and Pushes Air")
  • Ram Jet Engine ("SLAMS Air")
  • ScramJet Engine










Back in the late 1980's and early 1990's there was a lot of excitement about the NATIONAL SPACE PLANE.

This exceptional aircraft would take off from a regular airport runway, accelerate through the atmosphere, reach the edge of space and then come back down to Earth.

Flights from New York to Tokyo would take 2 hours.

Let's take a gander at this video.

While we're doing that, let's identify the several (?) different features of that "plane":

1) Where are the wings? How does the plane achieve lift in the atmosphere?

2) What types of engines that plane was going to use?




Notice that the plane was going to use scramjet, ramjet and rocket technologies.


From what you know of ramjet and scramjet engines generally, what sorts of problems do you think those engineers encountered that caused the National Space Plane to be cancelled in the mid 1990's?


Do you think we could build that plane using modern technologies?



Are we still working on such a plane?

Sorta kinda, but not really a plane... why not?