Static Port

[P Johnson]

I was not going to fit external static ports but I am now considering it, I have the Show Planes static ports which I did not use on a previous build, it replaces the simple pop rivet port that is used on Vans aircraft but is held in place by a nut rather than not fully setting the rivet. The installation of this port would be very similar as the backing plate would relocate the skin on a metal aircraft and I think this will give a nice finish on the fabric as I don't like the idea of just melting a hole, has anyone used these ports on their Kitfox SS7?

I will put a link below.

https://showplanes.com/Item/SP-01

Regards

Paul.

[patrick.hvac]

I have that one. Glued an aluminum backing plate to the fabric and bolted it in.

[P Johnson]

I have that one. Glued an aluminum backing plate to the fabric and bolted it in.

Patrick,

Thanks for the information, did you use .016 thick backing plate as I have concerns about the the fabric distorting due to the smaller size of the fitting.

Paul.

[alexM]

I have that one. Glued an aluminum backing plate to the fabric and bolted it in.
Since this is an active thread about static ports, how big should the aluminum backing plate be, and what would you bond it in place with?

[Delta Whisky]

Since this is an active thread about static ports, how big should the aluminum backing plate be, and what would you bond it in place with?

I'm not sure why you would put one in. The HS, wing to fuse junction, and doors leak in a major way and to my knowledge a static port location analysis has not been performed on any of the fuselages so . . . . . . .?

[jiott]

I used about a 2" dia. aluminum, 0.032", backing plate. Glue it to the inside of the fabric with Hysol.
Caution: you can also glue it with other products like Polyfiber PolyTak, but if the outside of the fabric is already painted, the PolyTak will cause your finish paint to bubble up because of the MEK in it. Hysol will not cause this problem.

[P Johnson]

The Kitfox static port kit instructions has the 2" in diameter backing plate fabricated from a piece of aluminium which is .016 in thickness, Skystar instructions (which are on this forum) just say fabricate the 2" in diameter backing plate from a supplied piece of aluminium but it does not state thickness, maybe Jim had that kit and it was .032. The Kitfox instructions and Skystar instructions have different location for the static port, Kitfox is 4 1/2" up from the lower longeron for the series 5-7 and Skystar 2 1/2" for the series 5. As my fuselage only has the brush coat of poly brush I will not have to worry about spoiling the paint, so I will poly-tak the plates to the inside of the fuselage in the location Kitfox states and and cover them with fabric, I also plan to have two ports one left and one right.

Should I fit the static ports at all, well I have them and have time to kill while waiting for the wings to be painted and the spray booth becoming available, if they are not accurate I can disconnect them and go with cockpit pressure, but in my experience one of the most important things is to have the ports outside the boundary layer (Bernoulli).

If I did not already have the ports and tubing from a previous project I would install the Kitfox static port kit as per their instructions just with one slight modification.

[jiott]

I did use the Kitfox factory static kit, and I was going by memory that the thickness was 0.032", but it very well could have been 0.016". It no big deal either way; you just want some extra stiffness besides the fabric. If you're making your own, just use whatever thin scrap you have laying around.

I put in just one static port in the Kitfox 7 recommended position on the left side. I kind of wish I had done dual ports, on both left and right sides. The single port works fine 99% of the time, except when I am in a hard slip I notice a small difference in indicated air speed depending on whether I am slipping to the right or to the left. I believe dual ports would eliminate this small anomaly.

I am going to stick my neck out a bit here, but I believe that if you just have an open static port inside the fuselage (no external ports), during a hard slip right or left, the many openings at the tail and the wing roots would allow the higher pressure air/wind coming from that side of the aircraft to blow into the inside and temporarily increase the air pressure on your inside static port, creating a small error in IASP. Dual external ports would average it out. Just my opinion; either way just a tempest in a teapot no big deal.

[PapuaPilot]

Two inch diameter sounds about right. The thickness of the sheet metal doesn't matter, but .016" would be fine because you put fabric on the inside and sandwich it.

I put two static ports in my model 5. The manual only called for one on the left side, but I added another one directly opposite on the right fuselage.

32032

[patrick.hvac]

Reference Page 72-73 of Dustin's build on this topic as well.
He ended up making some static port shields to deal with the accuracy. Even ended up posting the file, if someone wants to use it.

[SWeidemann]

I'm not sure why you would put one in. The HS, wing to fuse junction, and doors leak in a major way and to my knowledge a static port location analysis has not been performed on any of the fuselages so . . . . . . .?


I agree that a static port in a drafty Kitfox seems unnecessary.

[rv9ralph]

That draftiness in the cockpit will cause varying static port pressures, which makes an external port better for reliable reading on instruments that rely on static input.

In my model 3 the static port is cabin pressure. This makes my airspeed readings vary 5+ MPH while in steady cruise.

[SWeidemann]

That draftiness in the cockpit will cause varying static port pressures, which makes an external port better for reliable reading on instruments that rely on static input.

In my model 3 the static port is cabin pressure. This makes my airspeed readings vary 5+ MPH while in steady cruise.

My experienced Model 5 Vixen (original owner/builder started build in the 90’s & finally flew in 2003…that I did not build), has no plumbing to a pitot static system. Yes, the airspeed reads high but I’m used to it & do not view this deficit as enough of a hazard to retrofit tubes now. If I was a builder, I would put in the optional static port & tubing for sure.

Also, if I was building today, I would figure out a way to close off the tail section, wing roots & cowl sealing (to cockpit) to keep the air calm inside the cockpit. As an example this is possible, a friend restored his dad’s Aeronca and the cabin is draft free because he closed off all the opportunities for air to flow through the cockpit un-invited.