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.

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The second picture shows the vent open.

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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.

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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 (http://www.aircraftspruce.com/catalog/appages/snapvents2.php) mounted in the "kick panels" just in front of the doors.


It worked so well in 'Ol Yeller…

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I did the same mount in the Mangy Fox.

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[colospace]

Larry, I had seen your configuration in a previous search of posts, but figured it would just put air on my long legs (that will likely be splayed out to the side) rather than getting it on my face/neck. What is your experience in that regard. Sure looks like it would help Jim's feet out.

[Av8r3400]

I have short legs, so maybe this isn't the only solution for you "lanky" guys. :D

I will say that with the vent open, there is a considerable amount of air flowing around the entire cabin. These vents can be turned to take "ram" air, which is a considerable amount of flow, or they can be turned away from the airflow as a exhausting vent. It is surprising how much air movement this will cause. I often crack them open slightly backwards in the winter to keep air moving.

[PapuaPilot]

Does anyone else have poor ventilation airflow? I put NACA ducts just forward of my door with 2" SCAT tubing and eyeball vents. I thought it was going to be really strong airflow but it is almost nil. :confused:

[jiott]

My NACA ducts are somewhat higher than yours Phil and give quite a strong airflow when the eyeball is full open.

The vents that blow into the footwell area are a neat idea, but I would personally not want to give up my eyeball vents that I can aim right at my face and neck on those hot days.

[Paul Z]

In Texas the eye ball vents are useless, I've started cracking the doors open and use a Velcro strap to hold it in position. Plenty of airflow, and no modifications.

[gregsgt]

I bought a set of the Vista vents to put in my doors. I flew in a plane that had them before and was impressed with them. But as mentioned, I am nervous about cutting the holes. I'm going to wait for it to get good and warm out before I attempt it.


http://www.aircraftspruce.com/catalog/appages/vistavents.php

[colospace]

Paul, just curious if you have low flow or just low velocity thru your eyeball vents?

[HighWing]

This might work for some. I used it to force air through a cabin heater. The down side of that idea is that all air through the heater was ambient outside air. Recirc. is a lot better for heat. It might work for an eyeball vent. I made it by shaping a piece of foam, covering it with glass, then digging out the foam. One could be made for each side on the smooth cowl shaped to fit. It is also something that could be made later. The only mod would be to cut holes for the scat tubing through the firewall and instrument panel. It could be designed with a fairly straight run, with minimal internal friction.

[Jch]

When its warm I leave off the "cuff" that covers the wing (front spar) to windshield junction. Gives me a nice breeze. If it is too warm for that I fly with the doors off. Haven't had a problem with hot feet or legs.

[N981MS]

I bought a set of NACA vents from Van's and they work great. I live in the deep south. They are put in about where Phil's are. I used the cheap black plastic eyeball vents that came with them. To connect them I just bought some heater hose at NAPA that would allow a slip fit. The eyeball just butts up to the NACA inlet. No ducting at all.

I would do it again but I might spring for some better eyeballs.

YMMV

[Rfisher30]

Flying in the Houston area is just "hot!" My solution is to replace the little door knob for a 3D printed knob that allows me to crack open the door about 1". Cruising ~100 mph, the doors are rock solid and the cabin is so much cooler.

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[Jcard]

Got these works of art from someone on Instagram.
Love them.

[Rfisher30]

[QUOTE=Rfisher30;93406]Flying in the Houston area is just "hot!" My solution is to replace the little door knob for a 3D printed knob that allows me to crack open the door about 1". Cruising ~100 mph, the doors are rock solid and the cabin is so much cooler.

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I'm going to Post the *.stl files in Facebook/3D Airplane parts. These are not bling, but for less than $0.50 each I cannot complain.

[efwd]

Fantastic! I have never seen anyone do that. Im going to have to do it.

[jrevens]

The 3D printed knob looks like a great idea! I recently modified mine to basically do the same thing, but it took quite a bit longer to accomplish...

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[Rfisher30]

The 3D printed knob looks like a great idea! I recently modified mine to basically do the same thing, but it took quite a bit longer to accomplish...

2531625317These are quite nice. Oh would that I had a lathe in the garage! It seems we each address the problem differently yet similarly. Well done you.

[Rfisher30]

[QUOTE=Rfisher30;93408][QUOTE=Rfisher30;93406]Flying in the Houston area is just "hot!" My solution is to replace the little door knob for a 3D printed knob that allows me to crack open the door about 1". Cruising ~100 mph, the doors are rock solid and the cabin is so much cooler.

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Lesson learned: If the latch vibrates the knob and the door flies open, there’s a good chance the door will be seriously damaged. A Positive locking mechanism is Required. I removed the *.stl files from Facebook and continue to work the problem.

[desertdave]

Built these over the last couple of weekends. It cracks the doors open about 1/2" and positively holds them in place.

[GuppyWN]

Got these works of art from someone on Instagram.
Love them.

Brian Bush. He's on the Kitfox owners page on Facebook. His latches are perfect.

[Delta Whisky]

When its warm I leave off the "cuff" that covers the wing (front spar) to windshield junction. Gives me a nice breeze. If it is too warm for that I fly with the doors off. Haven't had a problem with hot feet or legs.

Yep - this is all I needed flying in the hot days of August in VA. Thanks. BUT - it may mean I'll have to fabricate the cuffs for winter flying. :(

[Kitfox Pilot]

Lesson learned: If the latch vibrates the knob and the door flies open, there’s a good chance the door will be seriously damaged. A Positive locking mechanism is Required. I removed the *.stl files from Facebook and continue to work the problem.[/QUOTE]


What kind of damage was caused? The kitfox videos always show just unlatching the door and letting it go. Just wondering.

[markyharris]

Coincidentally, I watched a youtube video from bowenaero.com 'Project Kitfox' today and he addressed this exact issue. He's using a latch that provides 2 positions, fully closed, or door held a 1/2 out open but still latched. I thought this was an elegant solution to this problem.

You can watch the video here; https://youtu.be/MUeRMN9m90Q?t=266. It will start at 4:26 into the video where he starts his discussion of this latch. Might be worth more research.

Contact Bowen Aero LLC about Brian Bush's door handlesbowenaero@yahoo.com https://www.bowenaerollc.com (https://www.youtube.com/redirect?v=MUeRMN9m90Q&event=video_description&redir_token=QUFFLUhqa244cXNhRURrd0JCZlJRdTN1dkRPaT NxeFFyZ3xBQ3Jtc0tsd21XV01jZUFxem45VWl4RWdKNWZ2Z0lp bk5wOWlJT3pveHhMUm1UeVp0cGNENVJYT0ltNnB2TFBlWjlnRT FxY2s0ZjAzU0d0SHVoUlRZRVAxaFl6dFBYX2JnRWJMTHVJcEFN S01qYnk2SXZCeWw3aw%3D%3D&q=https%3A%2F%2Fwww.bowenaerollc.com)

- Mark

[efwd]

I love the airflow you get by using this method. One downside. I flew for an hour to San Diego with the door propped open a little. This was the first time I did this and I had about 10" of the door seal come loose from the adhesive that remained on the plexiglass. Now Im researching a different kind of door seal that might have a better adhesive. Sort of the same thing I am doing for the turtle deck foam seal.

[desertdave]

I stuck the weather seal to the aircraft side of the gap. With the doors cracked the weather-stripping isn't in the airstream and you don't see the adhesive strip when looking at the door from the outside.

[efwd]

Ahh, I'll try that. Thanks Dave.

[jiott]

I had frequent problems with the door weatherstripping coming loose even though I don't crack my doors open. I finally used a 3M neoprene weatherstipping adhesive that someone recommended on this forum and it seems to have solved the problem for good. Wish I could remember the exact name and part # but its out at the hangar. Its black and works like contact cement-apply to both surfaces, let dry, then press together. Its sold at auto body supply shops.

[JohnB]

I replaced my door seals last winter with these:
https://www.realworktrucks.com/d-shaped-rubber-seal-trim-lok-x1153bt.html

(https://www.realworktrucks.com/d-shaped-rubber-seal-trim-lok-x1153bt.html)They have 3M Acrylic Automotive grade tape and so far are holding up great.

[desertdave]

I used a combo of https://www.amazon.com/gp/product/B013WDNB5M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
and https://www.amazon.com/gp/product/B07L9WXMXF/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Update:
The Amazon stuff didn't hold up very well. I ordered the stuff from the link in the post above and so far it is holding up well.

[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

[Rfisher30]

Lesson learned: If the latch vibrates the knob and the door flies open, there’s a good chance the door will be seriously damaged. A Positive locking mechanism is Required. I removed the *.stl files from Facebook and continue to work the problem.


What kind of damage was caused? The kitfox videos always show just unlatching the door and letting it go. Just wondering.[/QUOTE]

The door frame bent and one weld broke completely. The bubble door shattered and fortunately none of the pieces fell off.