# Does Raymer's installed engine equation include the weight of the pylon?

I am currently modelling an aero engine and require the weight breakdown of the individual components, I have the dry weight of the engine and need to verify the pylon and nacelle weight.

Raymer has presented an equation for the weight of the installed engine in his book $$W_{InstalledEngine} = 2.575 *(W_{Engine})^{0.922}*N_{engine}$$

Does this include the pylon?

• The equation is probably a (nonexact) curve fit to some data. So you have some variation around the equation to start off with. The error from the pylon (either way) weight could be insignificant, so you might as well ignore it. Just my opinion. – jjack Nov 30 '18 at 10:37
• Nengine is the number of engines on the aircraft. – martin Nov 30 '18 at 10:43