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Static System Calibration

bjdecker

Well Known Member
Ambassador
I'll put this story here since I think it is broadly applicable to the fleet/operators and not just a subtype.

I've been flying my second RV-7 for some 235 hours now, and never been happy with the performance (read: TAS) that I was able to get. This aircraft is well equipped, modern glass (Garmin G3X Touch), 200 HP stock engine, 72" CS BA Propeller...No reason why I shouldn't be able to reach Van's published numbers for the type.

Early on in the build, I was provided a set of static ports that were produced by a local machinist for a commercial aircraft company here in Texas; they looked good, the interface to the static plumbing was simple and leak free, and the installation only required a 1/4" hole -- why not.

Right out of the chute, I noticed that the performance wasn't the same as my previous RV-7 with the same equipment. I tinkered and tinkered and nothing worked. [sigh]... The paint shop called, and I took the airplane in, thinking maybe that a coat or 8 of expensive pigment would help :)

The paint shop delivered as promised and I couldn't be happier with the result -- but the airplane was no faster in cruise than before. WTFO? :mad:

Flash forward - I decided to gather some data and run it through the tools referenced by Kevin Horton in the following article https://www.kitplanes.com/flight-testing-finding-tas-from-gps-data/

What it showed was eye-opening, my calculated TAS was right in line with what Van's published *and* my altitude above mean sea level was off by +300ft (PALT was 6500, GSL was 6820).

I corrected the static ports by installing a .016" shim between the domed head and the fuselage skin. I flew again, and observed that the airspeed error was <2kts (172.3 Calculated vs 171 Observed) and the altitude was now 40ft low (PALT 6500, GSL 6460).

Learnings:
1. Data is your friend, go get it -- there are countless tools available to help analyze, predict & verify real world effects.
2. If it ain't right, it ain't right -- the fact that the new airplane didn't behave (or indicate the same) as the exemplar should have been a big red flag.
3. Don't be afraid of the answer -- If the data indicates there's a problem, be willing to change the system to fix it, there may be other side effects that are hiding in the data that can kill you. (Altitude difference in the case above).

Pictures attached -- before, and after..
 

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Seems to be a very common problem - the Van's recommended method using a rivet is simple, cheap, and works well. A dab of proseal on it, and it's not coming out.
 
I am not sure if using the VANS published numbers as your way of calibrating the speed is the best way to go and necessarily yields good result.

There is a simple 3-way GPS speed calculation that gives you an accurate way if your speed is correct.
Looking at your static ports, I would not be surprised if your speed is off and inaccurate.
 
I am not sure if using the VANS published numbers as your way of calibrating the speed is the best way to go and necessarily yields good result.

There is a simple 3-way GPS speed calculation that gives you an accurate way if your speed is correct.
Looking at your static ports, I would not be surprised if your speed is off and inaccurate.

Van's published numbers were a reference, an aspirational goal.

I used the 3 legs and 4 legs gps_pec.xls tool for the "calibration" as it were.

The tools showed that the aircraft is performing as well as, slightly better than Van's published numbers, however the EFIS was mis-reporting that information.

The static port profile is not *exactly* the same as Van's SD-42-BSLF rivet, the edge was a bit thinner, and there is a slight flat spot in the immediate vicinity of the orifice. The first picture was after shaving the excess paint flattening the dome a bit (which didn't change a darn thing...btw).

The underlying point of the original post, which folks may have missed, is to VERIFY the integrity and accuracy of the static system. Doesn't matter if you built it per plans, bought it from some dude who built it per plans, or rolled his own static ports, or whatever-you-may-have-installed.
 
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The underlying point of the original post, which folks may have missed, is to VERIFY the integrity and accuracy of the static system. Doesn't matter if you built it per plans, bought it from some dude who built it per plans, or rolled his own static ports, or whatever-you-may-have-installed.

Couldn't agree more. I went thru the same process on my RV7A since I had deviated from the plans and had used a flat faced static port. After many trial & error with using dams or other shaped items, I ended up a pop rivet shape static port which was much more accurate. Both of my RV14s were calibertated and proved to be within a fraction of a knot error at all speed envelops (slow, cruise and fast).
So, again it is good to verify the accuracy of your static port which will also affect your reported altitude.
 
As you build, make a list of each time you deviate from the plans. When you have a problem in the future with your RV, look back on the list and see if YOU created the problem.

Example.... In the 60's it was popular to install taller tires on the back of your 55 chevy (or whatever) and then compline that the speedometer was off by 10 mph and you got a ticket.
 
I too went through all of this 15y ago when the first aftermarket ports started appearing. There’s plenty of information available to avoid it.
Yet still literally every few weeks someone will post here about their plane being too slow or whatever and they’ll get an education on static PEC.

This should really be a big sticky at the start of the plans (assembly instructions…) because I reckon a substantial amount of the fleet has something non standard installed and the majority of owners never do the GPS testing.
(Maybe that’s an exaggeration, but I know nobody around here whose done it)

As Mehrdad says, it’s important as it affects more than airspeed.

Might be worth a poll. Definitely worth drawing everyone’s attention to again.

Cheers
 
Ditto on do actual GPS airspeed (multi- ways to do it some very wrong). You may know this, apologize if this is old news, but have to record Altitude, Temp, Local Baro, IAS, GPS ground speeds on 3 or 4 headings (tracks). Math will remove error from wind and give you TAS. [Definitions Calibrated airspeed (CAS) is the IAS (Indicated) corrected for instrument and position error, which is what we are trying to find out. TAS (true airspeed) is CAS corrected for Barometric Pressure (Altitude) and Temperature.]

Compare your measured TAS (GPS ground speed from multi runs mathematically manipulated to remove wind affect) to Instrument TAS. That is your instrument error. You will add or subtract that error for a given IAS to get CAS. Repeat at different speeds, because correction for CAS varies at different speeds. EFIS may allow you to put in correction, IAS is CAS. Also some EFIS shows TAS knowing Baro and Temp. With that and knowing GPS track/speed, it gives realtime wind vectors (estimated). Pretty slick. No E6B needed.

The math of taking GPS ground speed on 3 or 4 different headings at altitude, is not just simple averaging, which can produce calculated errors. The math is not hard and the formulas or calculators are on line. However I have done it as following that allows simple averaging.

One way I got quick and dirty measured TAS airspeed calculation was to fly along/parallel to freeway (rural) 500' agl (800' msl) with 5 mile straight section. It was not far from uncontrolled airport with AWOS (to get reported winds, pressure, temp). There are fixed mile markers on freeway I could see. I timed a 5 mile run. Then I reversed course and did the same timed run 180 degrees opposite direction. The highway was more or less North/South (same heading as nearby airport runway). The density altitude was at or near SL with high Baro and cool temperatures (some times sub SL). This simplifies the math, and is accurate if winds are more or less on the nose or tail. If slight off it still works and simple wind calculations can adjust the results.

The prevailing winds were generally from North or South aligned with freeway and runway nearby, but tried to pick calm wind day (nearby AWOS winds report). I calculated speed (Dist/Time) for each leg separately. Then I average the two, to take out wind affect. I did 2 or 3 two way runs and look at them for consistency. Crude and effective. I used the GPS ground speed as well as timing. I had three sources of speed, Indicated, Timed and GPS to compare. At low altitude, Std the IAS/CAS and TAS were close, being near SL. Also doing it low at SL, FULL power I could determine my Top Speed.

The advantage of being close to ground and knowing ground wind speeds adds another level of "known". Fiction slows the wind and makes it more consistent. If you do higher altitude wind triangle, wind can be variable and over the time. If wind is variable at altitude it really throws off that method. Close to ground knowing the wind is steady, direction and velocity is another data point or known. You can still do it along any rural straight freeway with mile markers regardless of ELEVATION. Last SAFETY IS FIRST, and follow all applicable FAR's.

Bottom line : Your new RV might be a bit slower than your previous RV, due to weight? Not saying it is, but what were the empty weights, HP, fit finish? It sounds like this bird might be fully outfitted? I looked at RV empty weights. RV's with IO360/390 angle valve, metal Hartzell, full full IFR panel, autopilot, deluxe interior and fancy paint, all added weight and had the highest empty weight. No shock. However it does not make the plane handle better. Weight does not make it takeoff, climb and fly faster or carry more payload. So if your new plane is heavier, then it would be likely a little slower, not much slower but a few MPH, given equal fit, finish, HP and Prop efficiency. Yes more HP helps compensate for weight, but at in weight and fuel burn. I had the pleasure to fly a very light RV-4's and 6's with O320's and wood props, day VFR panel. That was the norm 30 yrs or more ago in RV land, They were amazing. Then I flew an overweight RV years later. It just did not have the RV magic. KEEP IT LIGHT should be on ever work shop. I am now building and striving to avoid making it more complex and heavier, which is hard to do. Also diet and lose some pilot weight.
However if your TAS's are matching Van's numbers that is pretty good. Congrats and enjoy the RV, fly safe.
 
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Phase 1 is Flight Test

I've been flying my second RV-7 for some 235 hours now, and never been happy with the performance (read: TAS) that I was able to get. This aircraft is well equipped, modern glass (Garmin G3X Touch), 200 HP stock engine, 72" CS BA Propeller...No reason why I shouldn't be able to reach Van's published numbers for the type.
.
.
.
What it showed was eye-opening, my calculated TAS was right in line with what Van's published *and* my altitude above mean sea level was off by +300ft (PALT was 6500, GSL was 6820).

I corrected the static ports by installing a .016" shim between the domed head and the fuselage skin. I flew again, and observed that the airspeed error was <2kts (172.3 Calculated vs 171 Observed) and the altitude was now 40ft low (PALT 6500, GSL 6460).

Learnings:
1. Data is your friend, go get it -- there are countless tools available to help analyze, predict & verify real world effects.
2. If it ain't right, it ain't right -- the fact that the new airplane didn't behave (or indicate the same) as the exemplar should have been a big red flag.
3. Don't be afraid of the answer -- If the data indicates there's a problem, be willing to change the system to fix it, there may be other side effects that are hiding in the data that can kill you. (Altitude difference in the case above).

Excellent learnings. I spent 4 hours of flight test just on getting accurate OAT, whose probe location is another unending thread discussion point, in order to get more accurate airspeed calculations.

The underlying point of the original post, which folks may have missed, is to VERIFY the integrity and accuracy of the static system. Doesn't matter if you built it per plans, bought it from some dude who built it per plans, or rolled his own static ports, or whatever-you-may-have-installed.


I think the point/message should be that this should have been done in the 40 hours of Phase 1 flight test. Calibration of airspeed should be pretty high on priority for Phase 1.
 
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Excellent learnings. I spent 4 hours of flight test just on getting accurate OAT, whose probe location is another unending thread discussion point, in order to get more accurate airspeed calculations.

I think the point/message should be that this should have been done in the 40 hours of Phase 1 flight test. Calibration of airspeed should be pretty high on priority for Phase 1.

I did the same on #1 and agree completely on #2 - -why do any documentation of performance without calibration? Fun flying, but wasted effort for results.

I got my calibration early in PH1, but the OAT caught me by surprise. One day I caught the OAT going up with EGT - -what? Checked my flight data and it was definitely a correlation. It was not electrical either.
 
As you build, make a list of each time you deviate from the plans. When you have a problem in the future with your RV, look back on the list and see if YOU created the problem.

The real irony of this comment is that a very high fraction of those static systems that use the standard pop rivet approach have leaks. I was helping one pilot try to find a massive static system leak who swore up and down that the system hasn't been touched in 15 years and has always been tight. In reality, that system was probably leaking for the entire 15 years.

The stub end of the pop rivet is just not long enough to get a reliable tube engagement, let alone seal. Slathering with a big glob of RTV really just masks the problem and makes it harder to take apart and throw in the trash.

There are sources for good static taps that replicate the geometry of the pop rivet, but provide a good barb fitting on the back. Even Vans sells them now!
 
The real irony of this comment is that a very high fraction of those static systems that use the standard pop rivet approach have leaks. I was helping one pilot try to find a massive static system leak who swore up and down that the system hasn't been touched in 15 years and has always been tight. In reality, that system was probably leaking for the entire 15 years.
!

A rather generalized statement that I have
to disagree with Steve.

I won’t enter into an argument of what is a better static port, but saying one is bad just because some people have had leaks is not grounds for saying it should not be used. Leaks happen. In all manner of system designs.

A bigger issue is why does an RV ever get flown with a leak? It is simple to test for and should be part of the first flight prep checks.
 
There is a big difference between installing and maintaining a proven system and installing an improperly designed part.

Van's does have a machined part to replace the rivet. Heavy and expensive. But Van's sells things that Van would never install on his personal aircraft.
 
Well, I don't want an argument either, I didn't really say they were bad because some people have leaks. I said they were bad because the rivet tail is too short and does not leave a long-enough "tube" to get the plastic tubing pushed onto adequately. A longer-reach rivet, assuming one could get the nail out, would probably work OK.

A rather generalized statement that I have
to disagree with Steve.

I won’t enter into an argument of what is a better static port, but saying one is bad just because some people have had leaks is not grounds for saying it should not be used.
.
 
The simple pop rivet, driving the mandrel out is super cheap and easy and works kind of.

I have to agree making a leak free connection is not impossible but could be leak prone and many have been. A tiny static leak is not the end of the world, and you can have your static port INSIDE you cockpit (Cessna, piper alternate static).

The $30 machined one from van's goes from too simple and cheap to simple but expensive. $30? OK. You can go ACS, Wicks and get 30 different kinds of machined static ports for two for the price of one.

GETTING STATIC PRESSURE off the side of the fuselage is crazy difficult. Now add corkscrew airflow from prop, change is shape of fuselage and airflow from off of wing.

TWO IN ONE. Piper LONG has used a STATIC port combined with Pitot tube below the wing. Nothing stopping us from doing that. Two bent piece of aluminum tube. One for Pitot ala Van's planes. Another tube right next to pitot and bonded, tack spot welded to pitot. It will be slight shorter than the pitot as to cause flow problems with the pitot. The static tube has end blocked, with and a few holes drilled on the side of tube. TWO IN ONE.

https://www.aircraftspruce.com/catalog/inpages/pitot15144.php

THREE IN ONE. Now add a third tube to the two in one above for AOA. The most ingenious Pitot, Static, AOA probes I saw was on a LSA. It was three tubes (i believe they were stainless). Top was Pitot, Middle was static slight set back from pitot. Last was angle of attack on bottom set back from static and angled down 30 degrees (Approx).

LSA Three in One Pitot, Static, AOA
https://photos.app.goo.gl/i3uciCnrscuX48Tp7

Sketch of Three and One
https://photos.app.goo.gl/LfEtQghbPheMiCKD9
 
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Piper LONG has used a STATIC port combined with Pitot tube below the wing. Nothing stopping us from doing that.

And yet, not too long ago, there was a lengthy series of posts concerning the poor performance of a well known brand autopilot. Finally the OP mentioned that he had a Piper-style static port, and the autopilot company rep immediately said, ‘Oh, it won’t work with that!’ It’s all black magic as far as I’m concerned.
 
A static pressure probe consisting of a tube with a hemispherical tip and a set of holes about 8 diameters back from the tip is called a Prandtl tube. They can be quite accurate when perfectly aligned to the flow. The location and size of the holes is important. But they do show a sensitivity to angle of attack.

Locating a Prandtl probe back under the wing a little ways helps reduce the angle of attack sensitivity, since the wing tends to turn the flow, but that also changes the local pressure field near the probe. With a little bit of CFD a good location can be chosen that gives a fairly accurate static reading over most of a wing's angle of attack range.

Putting the static ports back on the fuselage is much less angle of attack sensitive. The problem is that because of the taper in the fuselage (and note here that an RV-7 will be a fair bit different than an RV-8), the local pressure is usually somewhat higher than freestream static (think "pressure recovery").
So a flush static port on the aft part of the fuselage will usually read too high a pressure, indicating a slower velocity. By making the static port NOT flush, but rather a shallow dome shape, a small area of accelerated flow exists around the port, and if that acceleration is just right, the local pressure at the port will be free stream pressure. The same can be achieved with a small ramp or dam in front of the port, but that is more hit-or-miss than adjusting the height of the dome.

Thus the focus of Brian's original post. By tailoring the height of the bump, you can tweak the local static pressure to be pretty close, over a wide speed range. I think it is likely that the side-by-side RVs will want a slightly higher bump than the tandem RVs.

How important is all this? Well, it depends on if you care to get good performance data, or if you are content to just take what you get. I do think that many standard pop-rivet installations leak and are basically reading cabin pressure, and yet they fly happily for years. Its not a big deal.

But if you want good reliable air data, the machined taps with a hose barb are much easier to get a good tight static system, and are easy to tune, as Brian has done, to be quite accurate. Complaining about the $30 cost? Really? How much are you going to pay the avionics guy to come out and do a FAR 91.410 static system check, have him tell you it leaks, you fix it, and he has to come out and do it again? Most shops are charging more than $100 for a 91.410, plus the extra time and scheduling hassle. Been there, done that. $30 seems cheap to me.
 
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I used the pop rivets with Pro-seal (proseal rules), been good for the last 20 years.
One big error Van's made was to suggest folks force a 'T' into the Nylo line, heated or not, it's not made to be expanded and will eventually crack, replaced many.
 
A static pressure probe consisting of a tube with a hemispherical tip and a set of holes about 8 diameters back from the tip is called a Prandtl tube. They can be quite accurate when perfectly aligned to the flow. The location and size of the holes is important. But they do show a sensitivity to angle of attack.
Interesting I did not know the name. Why is static sensitive to Alpha if holes are on side of the tube? I think I understand. Changing the flow around the tube from in line with tube to transverse would change local pressure. However AOA in normal cruise climb, cruise, cruise descent, approach is small and therefore error is nil. I did flight test on a few planes and slow speed high AOA the Airspeed was always off a few MPH regardless of where static port was. You made interesting points.

Static-1.jpg.webp


Locating a Prandtl probe back under the wing a little ways helps reduce the angle of attack sensitivity, since the wing tends to turn the flow, but that also changes the local pressure field near the probe. With a little bit of CFD a good location can be chosen that gives a fairly accurate static reading over most of a wing's angle of attack range.
I always wondered how Piper got away with Piot + Static probe under wing. One it is not very long to my eye so the ports are close to lower surface. Apparently it works. Also the static port is on the trailing edge of the blade. I do NOT recommend this for an RV, but experiment if you like. Looks 10 out of 10 however. The other DIY under wing pitot or static tubes you can make is experimenting. Mounting it say near the bell crank access, you can remove it, change it, modify it and tune it. I am likely to follow the planes (except for the static pop rivet. As far as heated Pitot. A small single engine plane has no business in icing. I have flown in small singles (P210) and twins (Seneca III) all turbo charged and known ice. No thanks. If your pitot is blocked due to ice you made bad life decisions.

iTsQ2.png


Putting the static ports back on the fuselage is much less angle of attack sensitive. The problem is that because of the taper in the fuselage (and note here that an RV-7 will be a fair bit different than an RV-8), the local pressure is usually somewhat higher than freestream static (think "pressure recovery").

So a flush static port on the aft part of the fuselage will usually read too high a pressure, indicating a slower velocity. By making the static port NOT flush, but rather a shallow dome shape, a small area of accelerated flow exists around the port, and if that acceleration is just right, the local pressure at the port will be free stream pressure. The same can be achieved with a small ramp or dam in front of the port, but that is more hit-or-miss than adjusting the height of the dome.

Thus the focus of Brian's original post. By tailoring the height of the bump, you can tweak the local static pressure to be pretty close, over a wide speed range. I think it is likely that the side-by-side RVs will want a slightly higher bump than the tandem RVs.
It has been known and discussed, going back to my entry in RV building in late 80's, flush or low profile static ports on side of a RV6 produced errors, "bump" required. I know. I put a flush one on my RV-6. It did not work well. I looked at factory planes on ramp. and saw surface mount static ports with a disk around it. I used a Cessna style static port like one above and clones you can buy new below. Cessna style come in 3 rivets or 4 rivets to mount (you could bond it). Some have protruding head rivets or flush rivets. Also unlike most aftermarket static ports, with (1) hole typically, where Cessna ports have THREE (3) SMALLER HOLES. I suspect this is not an aero decision but to keep something from crawling into it. Which is a cool idea. T

Look at a jet, below the cockpit side of fuselage behind the radome. You see Pitot probes (angled with fuselage shape), Static ports (no paint around them), and AOA vanes. Having an unpainted flush ports and the area around the the static with no structural waviness is critical for these installations, especially now, with RVSM where jets are separated by only 1000 ft in class A airspace. I was involved in Jet certification and flight test. To get static during flight a static cone is towed behind the plane. Take off and the cone is reeled out a few 100 feet behind the plane, to get ambient static pressure in undisturbed air. Once data is collected, flight computer is programed to make corrections for different flight and aircraft conditions. [Q: Do any of the popular EFIS EAB planes, Garmin, Dynon, Avidyne , GRT, allow IAS to CAS correction?]

How important is all this? Well, it depends on if you care to get good performance data, or if you are content to just take what you get. I do think that many standard pop-rivet installations leak and are basically reading cabin pressure, and yet they fly happily for years. Its not a big deal.
Agree but I would avoid the pop rivet method for static, since there are better solutions which are more reliable.

But if you want good reliable air data, the machined taps with a hose barb are much easier to get a good tight static system, and are easy to tune, as Brian has done, to be quite accurate. Complaining about the $30 cost? Really? How much are you going to pay the avionics guy to come out and do a FAR 91.410 static system check, have him tell you it leaks, you fix it, and he has to come out and do it again? Most shops are charging more than $100 for a 91.410, plus the extra time and scheduling hassle. Been there, done that. $30 seems cheap to me.
Yes "Really?". I am like Richard Van Grunsven. Ha ha. (Van is famously frugal and why his designs are so elegant, KISS.) Van's Aircraft is known for value to customers, even in replacement parts. However this one accessory sticks out. Compare it to much more elegant better machined Static ports on ACS or Wicks for about $15. I used a Cessna static on my RV-6, 30 yrs ago. Worked well.

https://www.aircraftspruce.com/pages/in/staticports/alumstaticports.php
https://www.aircraftspruce.com/catalog/inpages/staticports5.php

Van's $30 static port is over priced and frankly looks a tad crude, a glorified pop rivet albeit with better tube connection. BTW it is X2= $60. Also you imply pay $60 for these barbed ports or you will have a leak. No and No. First I would test for and fix static leaks before getting my Pitot/Static/Transponder checked. I'm NOT for the pop rivet static ports at all. never.Let's not get into strawman arguments or non non sequitur arguments. What is the best static port for a RV (Side by Side).

Van's $30 port one hole install, good, barbed tube attach, good, low profile small diameter, may be not so good.
"These static ports have been designed to replicate the shape of the SD-42-BSLF rivet rationally used and supplied in the STATIC KIT."

https://store.vansaircraft.com/medi...44c8de69c4fe4556d7871/s/t/static_port_kit.jpg

I 100% agree with you $30 is peanuts in the big scheme of things. My point is $30 is over priced and there are as good or better options (not pop rivets) that may work better and be less expensive. That is all. We see van's accessory static needs to be be shimmed. It is not ideal. Builders see ONE hole and small and stealth "hidden" static. Hidden or stealth ports do not necessarily good ports, e.g., Cessna surface mount disk. Also again look at jet. The area around static port the size of a very large dinner plate is polished and smoothed. Obviously different applications with smooth boundary layer flow, but my point is area around the static port is critical, even on our sky scooters. With PROP wash and fuselage "pressure recovery" it's approximate. That is why I am tempted to go with a Prandtl probe.

However I am more likely to put a Cessna style surface mount on with a proud disk, which BTW can be tweeked with fillet sealant around it, but it works well as designed. Tweeking with fillet sealant on edge of disk was not necessary. It is not stealth with a 1.5" disk and 3 or 4 rivet holes (although metal bonding is an option). The viable surface disk is why it works. My IAS to CAS on old RV were within a few knots from slow flight to top speed. Good enough. Warning when or if you paint your plane, be careful, don't pile paint up around and on the static port as I see some planes on the ramp.
 
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I said they were bad because the rivet tail is too short and does not leave a long-enough "tube" to get the plastic tubing pushed onto adequately. A longer-reach rivet, assuming one could get the nail out, would probably work OK.

No desire to enter the debate, but did want to clarify that pushing the nylon tube onto the rivet tail will not work well, as you mentioned, but also not the approach recommended by Vans. They have you attach a 1/8" ID rubber tube to the nylon tube and push that rubber tube over the rivet tail. The rubber conforms and seals well and a bit of pro seal or RTV will keep it from coming off. You also want to compress the rivet enough for the tail to bulge just a bit at the end. This creates a classic barb style fitting to hold the tube on.

Larry
 
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I used the pop rivets with Pro-seal (proseal rules), been good for the last 20 years.
One big error Van's made was to suggest folks force a 'T' into the Nylo line, heated or not, it's not made to be expanded and will eventually crack, replaced many.

The basic static system isn’t supplied with Nyloseal line. It is supplied with polyethylene tubing, which has always done fine being stretched over a hose barb to get a tight seal.
 
I always wondered how Piper got away with Piot + Static probe under wing. One it is not very long to my eye so the ports are close to lower surface. Apparently it works. Also the static port is on the trailing edge of the blade. I do NOT recommend this for an RV, but experiment if you like. Looks 10 out of 10 however. The other DIY under wing pitot or static tubes you can make is experimenting. Mounting it say near the bell crank access, you can remove it, change it, modify it and tune it. I am likely to follow the planes (except for the static pop rivet. As far as heated Pitot. A small single engine plane has no business in icing. I have flown in small singles (P210) and twins (Seneca III) all turbo charged and known ice. No thanks. If your pitot is blocked due to ice you made bad life decisions.

Something most people aren’t aware of, is that there is a whole bunch of different part number blade style, Piper pitot tube assemblies. There are many different angles on the bottom, where the static port is, And some of them are different lengths. I imagine this is because they are custom tailored to the different airplane models, depending on their wing cord size, etc.
This is likely why I am unaware of any RV ever built using one, having accurate instrument readings using the static source on the blade.
 
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The basic static system isn’t supplied with Nyloseal line. It is supplied with polyethylene tubing, which has always done fine being stretched over a hose barb to get a tight seal.
Ok my bad, it's the tubing that connects to the tee running forward, which is generally nylon or Nylo which gets stretched over the tee.
 
Ok my bad, it's the tubing that connects to the tee running forward, which is generally nylon or Nylo which gets stretched over the tee.

Maybe you have run into instances that builders used a different tubing?
The basic static system kit has always come with a 1/4” O.D. Poly tubing for the main static line plumbing, and a smaller diameter clear vinyl tubing for the interconnect between the two static ports.
 
One of the things that hasn't been talked about which in my view has a big factor is if this is an IFR or VFR plane.

The standard VANS static port works accurately and may seal OK but its reliability for sealing over the years may not be as much as other type connectors. As a VFR plane, we are not required to check for static system and if it leaks a bit, it is not a big deal. But for a IFR plane which will be certified every two years and any leak could cause it the certification to fail, it is more of a big deal and a more reliable port will pay for it in a long run.
 
Maybe you have run into instances that builders used a different tubing?
The basic static system kit has always come with a 1/4” O.D. Poly tubing for the main static line plumbing, and a smaller diameter clear vinyl tubing for the interconnect between the two static ports.
Found many like this, the nylon tube going fwd will crack at the tee every time when stretched over the tee:
(I'm pretty sure this was per the plans less the fancy ports)
 

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Something most people aren’t aware of, is that there is a whole bunch of different part number blade style, Piper pitot tube assemblies. There are many different angles on the bottom, where the static port is, And some of them are different lengths. I imagine this is because they are custom tailored to the different airplane models, depending on their wing cord size, etc.
This is likely why I am unaware of any RV ever built using one, having accurate instrument readings using the static source on the blade.
Great point. The one I bought and contemplated using was short, 5" may be. When I looked I saw some on the inter-webs much longer. I never used it. This was 30 yrs ago, paid $20 for this Piper blade pitot/static with working heat. I sold it long ago. I see them looking like they were at the bottom of the sea going for Mucho Dinero. Wish I had a box of them....:D
 
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