SonexBuilders.net

This is not my idea, Peter Anson was the first one to do this and he posted his version on the SonexAus wiki pages here:
http://sonexaus.wikispaces.com/Peter+Anson+-+Sonex+894
(scroll to the bottom of the page)

Peter reported great improved of air flow in the cockpit after installing the 3D printed vents onto the standard cut outs. (up to the point where he can’t fully open the vents even on a warm(-ish) day as he explains on the website above)

Anyway, I’ve got the standard vents cut out of my fuselage side panels as well (I bought these panels from another builder who had them done already) so I was hunting for some sort of solution better than the silly little plate that opens with a piece of phenolic as per the Sonex plans.

I was very excited to see Peter’s design and I do have a friend who built his own 3D printer so I decided to do something similar but I kept the design a bit simpler (mainly because my 3D drawing skills are not as good as Peter’s).

Anyway, here’s what my vents look like, I don’t think I need to explain how they will work, the pictures are self-explanatory,
They are installed onto the side wall with machine screws so I can easily remove them, which is good because this is only version 1, I will probably refine the design over time.

The design drawn in SolidWorks


The parts:





The vents assembled, one in the full open position, one in full closed position:




One area for improvement I found already is the 5/32 screw that is used to open/close the vent needs to be a courser pitch, it takes too many turns on the wheel now to go from full open to full closed.
Other than that I think the design will work, not as neat at Peter’s but still functional.

I'll post some more pictures once they're installed but I first need to finish painting the fuselage...

Hi Michael
This is a great fix Peter has come up with to replace those useless standard vents. You guys should get together and go into production. The airflow adjustment mechanisms you guys have each come up with are just brilliant. Maybe Peter will post photos of his also ?

I stupidly followed the plans and was also stuck with the original vent location. I replaced the sonex cat flap vent with metal naca ducts a few years ago. My vents are either open or closed / Hurricane or draft. Apart from that they work really well on a hot day, especially whilst taxying.



Steve
Sonex 892

Great post! Happily filed away for when I reach that point. Thanks!

sonex892 wrote:Hi Michael
This is a great fix Peter has come up with to replace those useless standard vents. You guys should get together and go into production. The airflow adjustment mechanisms you guys have each come up with are just brilliant. Maybe Peter will post photos of his also ?

Thanks Steve,
Even though I'm sure mine will be effective, it is a bit of an amateur's design I'll improve it as my SolidWorks drawing skills get better.

I think Peter's is production worthy now.
Though he did say something about making the design such that he could print the main duct in 2 parts as the printer now has to print stuff "mid air" at stages which is not ideal...

sonex892 wrote:I stupidly followed the plans and was also stuck with the original vent location. I replaced the sonex cat flap vent with metal naca ducts a few years ago. My vents are either open or closed / Hurricane or draft. Apart from that they work really well on a hot day, especially whilst taxying.



Steve
Sonex 892

They look good in aluminium, Surely you can install a similar the opening mechanism as I have on mine which would allow you to adjust the flow a bit better.
Anyway, happy to hear they work as well.
It's funny how just adding sidewalls to the original openings make such a difference in the effectiveness of the vent. I'm sure there are aerodynamics behind it all which I don't understand.

Some pictures of the vents installed now:

Sorry to take so long to get back on this. I made a couple of different designs for my own Sonex and while they work well, I wasn't really happy with the quality. This is what I eventually came up with:

The only differences from Michael's vent are that it has an outlet duct to direct air flow and a very coarse thread control screw so open to closed is only 3 turns. They are for sale. If you are interested there is more information on my web site at http://www.ansoneng.com/sample-page/tail-wheel-spring-bracket/.

Peter Anson
Sonex 894
212 hours

I have a set of PA's fresh air vents I am getting ready to install in my Xenos side panels. I just finished installing the spoiler handle so now I can locate the vents and stay out of the way of the spoiler handle and cable. This really limits my choices of where to install the vent.

The picture shows the cutout marked on the side skin as high as I can get without interfering with the spoiler handle. This places the aft edge of the cut out approx. in line with the LE of the wing and maybe 5 or 6 IN. above the LE of the wing.

Has anyone placed the vent that close to the wing? My concern is a possibility of being too close to the wing and sucking air out the vent. I doubt that is the case but I thought I'd ask you all to see if anyone has functional vents similarly close to the wing LE.

I looked at pictures of a lot of finished planes and could not find one that didn't have the fresh air vent up at the top of the fuselage. So I decided to go with what is known to work well and moved the location to the top. It is near the spoiler handle but I think I can get at it without stubbing my fingers into the vent. If not, I could bend the handle out more than 15 deg.

I also fit a 2nd skin to the PA vent so when closed, the sidewall is flush on the outside. Also made this with smooth curves instead of the angular shape of the vent flap. Still have to shape a little clearance to allow for paint and then I'll either rivet or bond it to the vent flap. Now I just hope there is no interference from the tank.