Brent writes
" You have the double whammy of cowling drag to cool the intercooler and turbo plus the belly scoop. One IV I know of that added a belly scoop for an air conditioner condenser lost better that 10 Kts. That whole "P-51 scope added thrust" story is a myth, IMHO."

This "one IV" must have had the early scoop that was much lower into the air stream than the current models.  Wind tunnel tests with models resulted in this modification to the scoop.  I believe this was done in the year 2000/2001. How to tell?? A measurement from the center of the fuselage to the apex of the upper lip of the air-conditioning scoop should be 1 1/8th" for the newer model.

In my IV I compared data with the earlier prop tests that I did for MT and found that it was approximately 3kt loss at an average from 1000 foot cruise up to 20,000 feet.

I agree with Brent that the scoop probably does not /and never did, add any boost-- however I do believe that it can clean up the exhaust and it's turbulence along the belly.



Charlie K.  See me on the Web at  www.Lancair-IV.com