So Mike, I figured I would give the test a round 2.I'd be curious to see what the 5-blade focus fan blade would do for CFM. No idea how the pitch compares to the others. Might be worthwhile to eliminate all the variables and test out all 3 blades on one of the single contour (or focus) motors and just switch the blade. That would eliminate differences from the shroud, and differences in the motors (if they exist) by keeping as many variables the same. It does appear that the focus and contour motors are similar, but in looking them up they have different part numbers. Different motor specs? or something like a motor plug in a different orientation.
Too bad you can't locate the blades separately. You could swap two of the 11-blade units onto the contour fan if it showed an increase of X cfm. It looked like going from contour to focus 11-blade was a 500 cfm jump roughly on one fan.
First video shows fan blade and fan motor details, showing the differences and what was needed to fit a Focus fan blade to a Contour motor. I did not measure the motor mounts, but looking at both, I think the Focus motors could be installed in the Contour shroud. Plugs are the same so wiring harness can be kept.
Second video is the actual testing showing Amps and CFM using the same motor and shroud for all three tests.
So final result -
- Contour 6 blade fan moved about 3000 CFM
- Focus 11 blade fan moved about 3200 CFM (was rubbing a slight amount, possibly could move a little more)
- Focus 5 blade fan moved about 2300 CFM (a lot of rubbing, could get a couple hundred more CFM if clearanced better)