Where to place static ports

[DesertFox4]

Paul- that's pretty much the same results I encountered with the static ports until I vented to behind the panel and I had ports on both sides of my first Kitfox.
My model 4 is right on with the static behind panel. Only change I can get is a slight momentary fluctuation when I open my door quickly. If I open it normal speed not much happens. My encoder is accurate also. Go figure.

[HighWing]

This is an interesting discussion. For the record I like the factory location and do have the T with ports on both sides. This location was a late decision - late 90s - as the earlier airplanes had the port behind the panel. So my installation was a retrofit on a 1998 inspected Model IV. The new location determination was made because of owner comments on their ASI readings over the years.

The reason for this post is because it seems some are getting better accuracy with the port behind the panel and some on the fuselage. A possible reason for that. On my first airplane I decided to use the water manometer to calibrate the ASI. This is done to see if the needle is pointing where it should with a precisely measured column of water creating pressure at the Pitot Tube. I found that my ASI read low on the low end giving braggable numbers for stall and it read high on the high end giving braggable numbers there as well. I think it might be entirely possible that a more correct reading - static port one location vs. another - just might be a lucky compensation for a built in error in the high end of the gauge. I doubt many of us use the GPS to help calibrate the ASI at stall so who knows actually how accurate the stall numbers are. There is a IV here that the pilot will tell you stalls at 28 mph.

Then again, since none of us use dead reckoning any more and we get used to what the gauge says and fly accordingly, is there a real issue here?

[Dave Holl]

I have built my mk 7 with a pitot static head located out on the port wing, not quite ready to fly it yet so can't say how good it will be!

[Dorsal]

Then again, since none of us use dead reckoning any more and we get used to what the gauge says and fly accordingly, is there a real issue here?

Agreed, this is one of the reasons I have not addressed mine to date. My current motivation is to get better relative wind info and just the satisfaction of knowing the instrument is correct. I will be putting the T in the back sometime this spring.

[GaryNo]

Here is what I'm using out on the wing.Pitot + Static tubes.Series 7 SS.
http://www.aircraftspruce.com/catalo...?clickkey=7405

[WISDAN]

Mine is off a tee behind the panel also. All indications tested correct.

[Lion8]

I just installed two. One on each side of the fuselage, 5" up and 27"(I think) forward of the horz stab. Installing them was a real challenge. I'm still in the process of bringing this bird back to life. I took the seat out, supported the skin on the bottom, then crawled to the back. I don't have the windscreen in yet, so I rigged a block and tackle to the over head in my shop. Put the hook on my belt in the back. After I did the work, I had my son help me out by pulling me out backwards. I'm 5'7" and 175# and at 65 and not in a regular workout guy, this was tough. Not impossible, just tough. The kid got a kick out of watching me being pulled out backwards.

[jrevens]

I'm using something similar to GaryNo - a combination pitot/static mast on the wing, but I made my own.

[t j]

Lion8, if you need to get in there again to work on the static system or service the elevator tube bearing you can easily install inspection hole rings and cut a hole on the belly.

I installed the static port after I had covered and painted but before first flight. The factory did the flight testing to determine the best spot and came out with a retro fit kit right after I finished painting.

I also installed two to service the elevator tube bearing. One in front and one behind it so I can get both hands on it.

[av8rps]

I think we should all test our airspeed indicators for accuracy. With modern GPS capabilities it is far from difficult. I can't tell you how many times I've heard people that own aircraft in this design family telling others that the cruise speeds are much lower than the factory claims. And if you ask them about stall speeds they typically will state much lower numbers than is even possible. Not only is this most likely caused by a simple ASI error, but it is easily fixed if they just took the time to understand what is causing the error.

And I feel strongly that stating incorrect numbers is doing a disservice to those that are looking for information on designs they might be considering to purchase.

A while ago I saw a really good example of that on the Highlander forum; Potential buyers were hearing numbers all over the place from owners, but no one was providing any proof. So I went out on a nice night and flew my airplane at cruise speed, and took a panel picture that showed my tach, ASI, GPS, altimeter, and my VSI, and then posted the picture with a description of wind and temp conditions at the time, along with another picture showing the exterior of my plane with a general description of how my plane is equipped (tire size, gear type, prop and engine used, empty weight, etc) so everyone could see some actual proof of cruise speeds.

I say all that because my general opinion is that Kitfoxes are a lot faster than most people think they are. But we don't as a group do a very good job proving that to others that are interested in that information. Yeah, I know that a Kitfox is generally not chosen by people for its blazing cruise speeds. But kept in perspective, it is a pretty efficient little cross country cruiser (and it can land dang near anywhere to boot) that is generally underestimated by the aviation world for those capabilities.

Another good example of that is in the seaplane world; most perceive a Rans S7 on floats to be much faster than a Kitfox (on floats). But it is actually just the opposite. Now I don't know how that got started, but that was the seaplane communities general perception until I started flying my Kitfox next to the Rans airplanes in the area and starting posting proof of what my Kitfox will actually do on floats. In time, the perceptions changed and now the community better realizes how good of a choice the Kitfox makes if you want to build a seaplane.

Oh, and on a last note; I really don't think we will ever find a good place on the fuselage of our airplanes to place the static port. If you look at the proportions of a Kitfox compared to most other aircraft, the fuselage is very short and boxy, and tapers a lot front to rear. So finding an area where there is neither negative or positive pressure in normal flight in my opinion is nearly impossible. Add to the short and tapered fuselage issue the potential for some continual adverse yaw effect typical of short coupled aircraft (causing some minor lack of coordination - affectionately known as "Being a half a bubble off" ) and you have a scenario that in my opinion dictates that the static port be out on the wing in clean air. And even there, if you don't make an effort to fly with the ball in the center, that too will be off.

So I'll be keeping mine underneath my instrument panel...

Ok, I'll get off my soap box now