Ventilation

[colospace]

I'm just fishing for some thoughts on cockpit ventilation.
I am building an S7 with the bubble doors, so I am loathe to cut into the plexi for vents. When I did the demo flight with John McBean, just propping the door open with the door latch seemed to work well, so I had been thinking I would take a "wait and see" approach to adding NACA ducts.
I am having second thoughts about that approach as I would hate to deal with the mess and paint touch up later.
I am considering using a smaller than normal NACA duct with 1-1/2 inch SCAT tubing to eyeball vents in the panel.
I guess I am looking for some experience based input as to whether this will be adequate, inadequate or the whole thing is unnecessary. Thoughts?

[jiott]

My thoughts: I used the Kitfox factory eyeball vent optional kit with NACA ducts in the sides of the boot cowl. Am very pleased with them. I have never felt like I needed to crack open the doors in flight even in the hot summers here (Portland Oregon). It is really nice to be able to aim the vent wherever you want for both pilot and pax, as well as adjust the airflow rate. I mounted the eyeballs on the extreme right and left of my panel. I agree I didn't like the idea either of cutting into the bubble doors. If you install the NACA ducts you definitely want to do that early on, not later as an afterthought. Be careful making the cutout in the boot cowl for the NACA ducts; you only cut out about half the area. I know several people who rushed ahead without reading the instructions and cut way too much out. It is a ***** to fix after making that mistake.

[Dave S]

If you do a search on "Cabin vent" several previously posted threads will show up - many with pictures.

FWIW - unless you only fly in cold weather - a person does need vents of some kind. Also the side of the boot cowl is a good high pressure area for a vent

Sincerely.

[HighWing]

Not a Seven and not using the Eyeball vents, but my choice from back in the day was the NACA type vent. My original plan was to use some sort of tubing to direct airflow, but decided otherwise. Again, way back then, I was always a bit dismayed by the guys I saw with sponges tucked into the vent inlet to stop airflow in winter, so did a bit of modification.

The first picture shows the vent closed. The "door" was the cut out skin trimmed and repaired with glass/resin where needed. The hinge was a piece of thin glass/resin. I figures if a fishing pole could bend then so could my hinge. The benefit of the glass hinge ultimately is that it is very stable in vertical movement so the door always closed centered.

Naca 5.jpg

The second picture shows the vent open.

Naca 6.jpg

The third picture shows the inside with the shaping for the eventual attachment of tubing. The ring is attached to a lever that is shaped to hold the door open, whereas a spring holds it closed when not secured by the lever.

NACA 7.jpg

Another idea I had but never used, was gotten from what Boeing once used on the APU inlet on their 737s. It was a wing shape "T"ed off the cover on the hinge end. While closed the Winged T was in parallel with the air flow, but when opened, the Winged T deflected additional air into the duct. No pic of that.

[Flybyjim]

How about getting some cool fresh air to your feet, how has that been handled.

[Av8r3400]

I got a pair of these mounted in the "kick panels" just in front of the doors.


It worked so well in 'Ol Yeller…

IMG_0520.jpg


I did the same mount in the Mangy Fox.

IMG_1952.jpg

[Rfisher30]

Gary ~

I tried the open door for a short while until the door opened in flight. The flutter that ensued shattered the door frame and bubble. Longer story short, I now use the SnapVent and installation wasn’t that bad. Here’s my YouTube video on how I did it. https://youtu.be/45QSf4vaH2k