# Aerospace Comparing turboprop and turbofan

1. Feb 26, 2010

### balogun

i am involved in a project that involves comparing turboprop to trubofan.I want to compare their specific power .but turbofans are rated in newtons.can the power of a turbofan be calcuated by multiplying its thrust with speed of the aircraft at that thrust.

2. Feb 26, 2010

### FredGarvin

Yes. There is a, although outdated method, that is called thrust horsepower. It is uses a selected reference speed of 375 MPH that the math works out 1 pound of thrust to 1 HP.

$$THP=\frac{T*MPH}{375}$$

Really, a more substantial and meaningful comparison is in thrust SFC or Thrust Specific Fuel Consumption.

$$T_{SFC}=\frac{\dot{m_f}}{T}$$

3. Feb 26, 2010

### Brian_C

Chapter 1 of http://www.aiaa.org/content.cfm?pageid=360&id=1343" [Broken] defines a quantity called "overall efficiency," which is the thrust power divided by the rate of heat addition from the fuel. Other quantities of interest include specific thrust and fuel air ratio (from which TSFC can be found).

Last edited by a moderator: May 4, 2017