[Amps] Layout of tube

[k7fm]

There is an airplane analogy about using dual fans.  A few airplanes have 
one fan behind another.  One "modern" one is the Cessna 337, commonly known 
as the Mixmaster.  One fan on the front and one fan on the back.  These 
airplanes are less efficient than when the engines are side by side. 
Additionally, the rear engine can have cooling problems.  The main advantage 
of such an arrangement is what is known as "center line thrust".  When one 
engine quits on takeoff, there is no rotational thrust that wants to spin 
the aircraft (bad at low altitude).  Quick response to feather the dead 
engine is not required.  The only penalty is less rate of climb.

Although the fans are not as proportionally close as stacked fans, it does 
prove that they can work.  Since the flow is modified, pay attention to the 
cooling of the second fan - although muffin fans consume so little power it 
should not be a problem.

73,  Colin  K7FM