- Jet engines are rated in "pounds of thrust," while turboprops and turboshaft engines are rated in "shaft horsepower" (SHP).  This is because it is difficult to hook up a dynamometer (power measuring device) to the column of air coming out of a jet engine, while it is easy to hook one to the shaft of a turboprop.

- An equivalent measure to horsepower is thrust horsepower (THP).  THP = (Thrust x MPH) / 375.  or THP = SHP x 80% in the case of turboprop engines (the 80% is because the propeller "slips" a little in flight).

- Exhaust gases exit the exhaust at upwards of 1000 mph or more and can use 1000 gallons of fuel/hour or more.

- Turbine engines run lean.  Unlike gasoline engines, turbines take in more air than they need for combustion.

- Fuel can be injected into the exhaust section to burn with this unused air for extra thrust.  This is called an afterburner.

- A water/methanol mixture can be injected into the intake to increase the air density, and thus increase thrust.

- Turbine engines can be built on a small scale as well.  The turbine pictured below has a diameter of 4mm and runs at 500,000 rpm.  It was built by at MIT for purposes of powering an aircraft with a wing span of about 5 inches that was projected to fly about 35 - 70 mph with a range of about 40 - 70 miles.

Image from Aviation Week and Space Technology magazine (July 12, 1999)

- The ignition system on turbine engines is only necessary for starting, afterwards it is self sustaining.  In jets, the ignition system is also turned on for added saftey in "critical" stages of flight, such as takeoff and landing.

- A device similar to a spark plug is used for the ignition process, but it has a larger gap.  The spark is about 4 to 20 Joules (watts/second) at about 25000 volts and occurs between 1 and 2 times per second.

- Turbine engines will run on just about anything, they prefer Jet-A (AKA diesel, kerosene, or home heating oil), but can burn unleaded, burbon, or even very finely powdered coal!

- The above snowmachine uses an Allison turbine engine, a very common engine in helicopters (such as the Bell 206 Jet Ranger shown below).  A lot of horsepower can be put into a small package!  Note the intake and compressor are at the front of the engine, then the two side tubes take the compressed air and bring it around back to the combustion chamber and turbine and the exhaust exits out the middle.  There are many engines out there with strange configurations like this.