Cockpit Airflow

[MikeG]

My first post! /ubbthreads/images/graemlins/cool.gif

Has anyone considered venting the cabin forward? e.g. ducted into the front wheel well? Anyone ducting air to the front disks could insert venturis in the ducts and literally suck the cabin air out.

I can't see any reason to assume that cabin air must be exhausted out the back of the cabin. Surely it only needs to be exhausted to an area of lower air pressure than the cabin?

regards

Mike

 

[James]

My thoughts

I think as long as you have positive pressure from the eyeball vents and exits in the door windows then there shouldn't be any issues. The addition of the heli style vents would also help to pressurise he cabin.

Think of your cabin as a balloon, it easy really. Blow the bugger up and pop it!

Regards,

J.P

 

[Jim Glickenhaus]

This angular scoop really pulls air into the cockpit through the sliders.

 

I installed two sets of helicopter vents in my GTD's side windows. I got them from a place called Wicks Aircraft, I think. At any rate there are several places on the internet selling essentially the same thing. They are incredibly simple to install. Tape the plexiglass to prevent scratching, mark your spot, drill it out with a hole saw, and voila the vent pops right in. Takes about ten minutes and the cost for a pair of the vents, IIRC, is less than $10 plus shipping. They work very well, too.

There was another thread from about 6 - 8 months ago on ventilation and helicopter vents; you can probably find it with the search feature. It had some pictures and links to sites selling them.

Bob

 

[40 Bud]

The Helicopter vents work very well!! Get the large size (3 1/4" I think).Simple and effecient. I placed mine in the upper front corner of the door window. Just open the side flap window and you have extraction of the stale air. Could not be simpler.

 

[Howard Jones]

Mk4 It looks like you had the girls out for a lawn party. NICE, very nice!

 

If the NACA ducts above the headlights are used to duct air into the ventilation system these together with a two speed fan work most effectively as it is a high pressure area. Conversely, if the NACA duct in the centre just below the windscreen is used, this location is a low / zero pressure area and no air will be forced into the cabin. In my experience the addition of helicopter vents in the side windows are also very effective.

 

[David Morton]

What is the optimum way to cut the plastic to fit helicopter vents ?I'm looking at buying a variable diameter tank cutter unless there is a better way.
Dave M

 

[Mike Dozier]

My understanding is a simple hole saw works fine.
Not sure what a variable diameter cutter is...
but if it's the top shaped tool that drills increasingly
larger holes, I wouldn't use it on plexi...too much heat.

MD

 

[David Morton]

Thanks Mike,
The one I'm thinking uses a diamond tipped cutter on a
radius arm which you can set to the diameter of the hole you require. There's virtually no heat as its not a rotary tool but entirely manual. I think I'll go and get one and run it on a few pieces of spare window material first and then report back.
Dave M

 

There was a pretty extensive discussion of this subject a while back. I installed four of the vents in my GTD (I liked the first two so much I put two more in), using just a garden-variety hole saw I purchased at Home Depot. Use a cordless drill at a very slow speed, and tape over the area to be drilled to protect against scratches or cracking. You can file the edges of the hole after you're done if you want, but with a new hole saw you shouldn't even have to do that. Use a hair dryer to slightly heat the "wings" of the vent to facilitate installation if you need to. Just take your time and it's very simple--

Bob

 

[David Morton]

Bob,
Info much appreciated. I'll try it.
Dave m

 

Call me simple but I fitted helecopter vents in the windows to avoid fans. These are clear 3" dia plastic discs which fit into a circular hole cut in the window when closed, or flip up to open. They can rotate a full 360 degrees to point forward or back.

I usually point the drivers side forward and have the passenger window open. This gives a good through flow (while moving). If its wet then I point it back to avoid a face full of water.