Larry Vetterman designed this cool little vent. I'm sure it's sold through various outlets, but it's available through Van's Aircraft as part number CA LV-3 Ventilator for $65. This is the outer face of the vent. You can see where it has a ridge that is approximately .032" deep so that the outer face will be nearly flush when mounted to a canopy or fuselage.

This is the backside of the vent... it's what you'll see from inside the airplane. The holes are smooth and are appropriately-sized to be tapped for 4-40 screws according to the instructions included with the vent.

Here's the inside view of the vent rotated to the completely open position.

And here's what the airstream will see when the vent's completely open. According to some friends who have these installed, they provide copious amounts of air provided you install them in a high pressure area. Like any vent, if you mess up and install them in a low pressure area, they won't blow at all... in fact, they'll [literally] suck!

So, to install this bad boy, I started with a #40 drill bit (mostly because that's what was in the drill). I then enlarged the hole for a 3/8" (I think) Greenlee Punch center bolt. I used the Greenlee punch to make a perfect hole. These punches aren't cheap, but they really work well. I bought a bunch of them on eBay for about 30% of retail price. I think I've got almost every punch from 3/8" to 3-1/8". Very handy.

Riveted in place as seen from the inside of the canopy. Notice that it's not square with the canopy frame. I did this intentionally in hopes of shooting the incoming air towards my face instead of towards my arm!

Here's the view from the outside. I really like the way this thing looks. I hope it works!