Why air gap between windscreen and upper cowl?

What is the reason for the space? Seems the purpose of a windscreen is to deflect the air not aim it at your face.

It exists on my 2007 and I'm sure others as well.

Reg

 

Here's my thread on the topic. I like it better plugged...

http://vfrworld.com/forums/6th-generation-2002-2009/32137-plug-hole-yeah-thats-what-she-said.html

 

it is to keep the pressure equal in the empty space between bad billys ears :lol:

 

The way Mother Honda advertised it was that it was to help keep the rider cool by allowing a little bit of air to come in toward the rider even when tucked behind the screen. I don't think it does much, @ full tuck it's mighty quiet behind the screen at "highway" speeds.....:whistle:

 

The reason for the air gap between the windscreen and upper cowl was said to be twofold Reg.

Metallican has the first part correct,at lower speeds Honda said that air gap between the windscreen and upper cowl was a pathway for a little more airflow to help keep the rider a bit cooler.

At high speeds though the function of that air gap changed. At high speeds the air that's rushing over the top side of the windscreen travels upward until it meets the top edge of the windscreen,at which point it no longer continues to travel upward for very much longer but actually starts to curve downward. That downward curving airstream hits the rider at a low angle which causes drag.

By simultaneously flowing high speed air on the underside of the windscreen it helps to push that downward curving airstream up just a little bit higher so that it hits the rider at a much higher angle. This is supposed to help reduce drag and make the bike a little more aerodynamic as it moves through the air at high speeds.

When Honda released the 5th gen. bikes they made a big to-do about it having a 9 percent lower drag coefficient than the 4th gen. bikes and that air gap at the front of the windscreen was said to have been a big part of it.
Makes you wonder because the 4th gen. bikes had an opening at the front of their windscreens too.

 

If a given space were theoretically empty, the pressure would be equal. .... and this dude works in a technical capacity? LOL Also if any other claims are made concerning this phenomena, do not subscribe to any offers of this dude giving head.

Some of the dynamics of windscreens and fairings can be explained in the subsonic calculations in L/D. For those who have the rare VFRs that go Mach, go figure.

 

I have a degree in aerospace and I agree! I don't go past 100 mph on the ground...so a slight reduction in drag at these speeds seems...trivial at best.

But hey, still love the bike!

 

The pressure in the empty space would only be equalized when at rest. Say on a couch or parked in front of a computer. Any motion, however unlikely would cause a pressure difference.

 

Ain't nothin cool about having a Harley, it's all in the head.

 

Great bikes! Got two. BTW nice writeup on several VFR's in the latest Cycle World Magazine in their used bike feature.

Gosh, we have a girly who texts at the ton whose L/D must be in the 1:1 range. The question now is, is she a drag queen or does she just need a lift.

 

It's not the Head, its the rear exhaust pipe trying to BBQ the Ham string that's not cool.

 

Would that be an octal hamstring or just high on the Hog?

 

So much for us winter riders.

Why haven't other manufacturers followed suit?

Reg

 

That would be the Semimembranosus and the Semitendinosus. Couldn't be high on the Hog it's 4" lower than the VFR.

 

The flow compensation vents can be modified for winter riding by covering the vent with genuine Honda duct tape.

 

I dunno. That my friend is the $64,000 dollar question. :noidea:

 

What you said seems to be born out in '98 Specs Sheet below.
http://pages.cs.wisc.edu/~john/vfr/specs/pics/98-vfr800-specs.jpg

" Air Flowing through central air vent under the front shield provides cool air to the rider at low speeds and raises the air stream hitting the rider at high speeds. "