A friend of mine who is a pilot, FAA designee (I think) and is VERY 
knowledgeable about kit aircraft and who shall go unnamed started 
telling me about this new airplane he wants to design using a 
Chevy engine. 

He went on and on about how low the RPM was that he planned to use. 
Sheeesss! Now I have to explain for the next five years  that RPM is 
NOT the limiting factor in how much HP an  engine will safely generate 
over a long period. These two KP articles set the aircraft engine awareness 
back about five years in the aviation community. This guy should know better.

He also mentioned  his truck and how it pulled all that well with
its Chevy engine. We also talked about the Cd of the truck and he said he 
thought it was about 0.65 so we went through the numbers. Camper shell is 
eight feet wide, eight feet tall, 64 square feet of frontal area.

BTW cars are less than 20 square feet and Cd's less than 0.35. 

Drag = Cd X FA X 0.0026 X MPH^2

0.0026 is the sea level air density constant when MPH are used.

Lets try 70 MPH. Drag = 530 pounds. 

HP = Drag X FPS / 550

70 MPH = 100 Feet Per Second. HP = 96 HP.

Suddenly I noticed the light bulb come on when I suggested he install 
a manifold pressure gage in his truck :-) 
 
Paul Lamar
 
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