Original Posted By: TLC62770(at)aol.com
I was just wondering what size tubing should be use for the pitot tube. Iwas thinking of using stainless 1/4 inch tubing. Is this big enough. ShouldI run two lines or is the static tube in the cockpit sufficient. Shouldthe tube be located in the leading edge or on the strut. I have seen themin both locations. What are the advantages and disadvantages of each? jasjimsury(at)fbtc.net________________________________________________________________________________
Pietenpol-List: pitot tube size
Pietenpol-List: Re: pitot tube size
Original Posted By: Ed0248(at)aol.com
THIS IS SOMETHING I HAVE WONDERED ABOUT ALSO WE AREN'T TO THAT POINT YET BUTWE NEED TO THINK ABOUT IT REAL SOON . HOW FAR ALONG ARE YOU ON YOUR PROJECT ?WE ARE JUST STARTING THE AIR FRAME . WE HAVE SEVERAL RIBS MADE NOW , BUT AMTHINKING WE BETTER GET THE STARTED ON THE BIG THINGS FIRST . WE ARE ALSOSTARTING WORK ON THE CORVAIR ENGINE WHEN WE GET STUCK ON OTHER ITEMS . WE AREDOING A COMPLETE OVER HAUL ON THE ENGINE . THE CRANK IS IN GREAT SHAPE , THEBLOCK IS ALSO . WE ARE GOING TO USE NEW CYLINDERS , PISTONS , VALVES , SPRINGS, RODS . THE CAM SHAFT IS NEW AND IS A LITTLE MORE DURATION THEN THE STOCKCAM GOT TO GO FOR NOW .________________________________________________________________________________
THIS IS SOMETHING I HAVE WONDERED ABOUT ALSO WE AREN'T TO THAT POINT YET BUTWE NEED TO THINK ABOUT IT REAL SOON . HOW FAR ALONG ARE YOU ON YOUR PROJECT ?WE ARE JUST STARTING THE AIR FRAME . WE HAVE SEVERAL RIBS MADE NOW , BUT AMTHINKING WE BETTER GET THE STARTED ON THE BIG THINGS FIRST . WE ARE ALSOSTARTING WORK ON THE CORVAIR ENGINE WHEN WE GET STUCK ON OTHER ITEMS . WE AREDOING A COMPLETE OVER HAUL ON THE ENGINE . THE CRANK IS IN GREAT SHAPE , THEBLOCK IS ALSO . WE ARE GOING TO USE NEW CYLINDERS , PISTONS , VALVES , SPRINGS, RODS . THE CAM SHAFT IS NEW AND IS A LITTLE MORE DURATION THEN THE STOCKCAM GOT TO GO FOR NOW .________________________________________________________________________________
Pietenpol-List: Re: pitot tube size
Original Posted By: Ted Brousseau
As I remember my high school physics, (and a little cheating by looking at aCesna 120) 1/4 inch aluminum tubing should work well for your pitot tube.Only one line is required, as there is no return path to the pick-up. As forlocation, it should be placed to keep the inlet out of turbulent air, eitheron the strut or beneath the wing. Just make sure that there are (1) no sharpbends, (2) is paralell to the airstream in normal flight configuration, and(3) covered when not in use. The bugs make effective air dams in the lines,and dam is the mildest word you will use!For the "useless information" file: Pitot ain't really a word. Thescientific term for ram air pressure is P (sub)tot, standing for Pressuretotal. Pronounced "Ptot", you now have a fancy word. The airspeed indicatoris just a calibrated gauge to measure that ram pressure, or ptot pressure.Gee-whiz, huh?Ed ________________________________________________________________________________
As I remember my high school physics, (and a little cheating by looking at aCesna 120) 1/4 inch aluminum tubing should work well for your pitot tube.Only one line is required, as there is no return path to the pick-up. As forlocation, it should be placed to keep the inlet out of turbulent air, eitheron the strut or beneath the wing. Just make sure that there are (1) no sharpbends, (2) is paralell to the airstream in normal flight configuration, and(3) covered when not in use. The bugs make effective air dams in the lines,and dam is the mildest word you will use!For the "useless information" file: Pitot ain't really a word. Thescientific term for ram air pressure is P (sub)tot, standing for Pressuretotal. Pronounced "Ptot", you now have a fancy word. The airspeed indicatoris just a calibrated gauge to measure that ram pressure, or ptot pressure.Gee-whiz, huh?Ed ________________________________________________________________________________
Pietenpol-List: RE: pitot tube size
Original Posted By: Steve Eldredge
Ed0248(at)aol.com[SMTP:Ed0248(at)aol.com] wrote:As I remember my high school physics, (and a little cheating by lookingat aCesna 120) 1/4 inch aluminum tubing should work well for your pitottube.Only one line is required, as there is no return path to the pick-up. As forlocation, it should be placed to keep the inlet out of turbulent air,eitheron the strut or beneath the wing. Just make sure that there are (1) nosharpbends, (2) is paralell to the airstream in normal flight configuration,and(3) covered when not in use. The bugs make effective air dams in thelines,and dam is the mildest word you will use!Good information except for the part about "only one line is required." Two lines should be used. Using one line relies on the pressure in thecockpit for the static pressure and this can vary depending on a lot ofthings such as if the front cockpit cover is on or off. It also doesnot allow adjustment to calibrate the airspeed. As noted in otherposts, adjustment is usually done by putting a small grommet or collaron the tube slightly ahead of the side holes and adjusting the locationas needed.The size of the lines is not important. Just pick something easy towork with and not too flimsy. 1/8 to 1/4 inch should be about right.Jim________________________________________________________________________________
Ed0248(at)aol.com[SMTP:Ed0248(at)aol.com] wrote:As I remember my high school physics, (and a little cheating by lookingat aCesna 120) 1/4 inch aluminum tubing should work well for your pitottube.Only one line is required, as there is no return path to the pick-up. As forlocation, it should be placed to keep the inlet out of turbulent air,eitheron the strut or beneath the wing. Just make sure that there are (1) nosharpbends, (2) is paralell to the airstream in normal flight configuration,and(3) covered when not in use. The bugs make effective air dams in thelines,and dam is the mildest word you will use!Good information except for the part about "only one line is required." Two lines should be used. Using one line relies on the pressure in thecockpit for the static pressure and this can vary depending on a lot ofthings such as if the front cockpit cover is on or off. It also doesnot allow adjustment to calibrate the airspeed. As noted in otherposts, adjustment is usually done by putting a small grommet or collaron the tube slightly ahead of the side holes and adjusting the locationas needed.The size of the lines is not important. Just pick something easy towork with and not too flimsy. 1/8 to 1/4 inch should be about right.Jim________________________________________________________________________________
Pietenpol-List: Re: pitot tube size
Original Posted By: Ed0248(at)aol.com
Thanks for the information. Didn't know Ptot ain't a word. Now I do. Asfor the size 1/4 in. tubing will work just fine. I guess I could havecheated and looked too but didn't have anything close at hand to look at.>As I remember my high school physics, (and a little cheating by looking at a>Cesna 120) 1/4 inch aluminum tubing should work well for your pitot tube.>Only one line is required, as there is no return path to the pick-up. As for>location, it should be placed to keep the inlet out of turbulent air, either>on the strut or beneath the wing. Just make sure that there are (1) no sharp>bends, (2) is paralell to the airstream in normal flight configuration, and>(3) covered when not in use. The bugs make effective air dams in the lines,>and dam is the mildest word you will use!>>For the "useless information" file: Pitot ain't really a word. The>scientific term for ram air pressure is P (sub)tot, standing for Pressure>total. Pronounced "Ptot", you now have a fancy word. The airspeed indicator>is just a calibrated gauge to measure that ram pressure, or ptot pressure.>Gee-whiz, huh?>>Ed >>jimsury(at)fbtc.net________________________________________________________________________________
Thanks for the information. Didn't know Ptot ain't a word. Now I do. Asfor the size 1/4 in. tubing will work just fine. I guess I could havecheated and looked too but didn't have anything close at hand to look at.>As I remember my high school physics, (and a little cheating by looking at a>Cesna 120) 1/4 inch aluminum tubing should work well for your pitot tube.>Only one line is required, as there is no return path to the pick-up. As for>location, it should be placed to keep the inlet out of turbulent air, either>on the strut or beneath the wing. Just make sure that there are (1) no sharp>bends, (2) is paralell to the airstream in normal flight configuration, and>(3) covered when not in use. The bugs make effective air dams in the lines,>and dam is the mildest word you will use!>>For the "useless information" file: Pitot ain't really a word. The>scientific term for ram air pressure is P (sub)tot, standing for Pressure>total. Pronounced "Ptot", you now have a fancy word. The airspeed indicator>is just a calibrated gauge to measure that ram pressure, or ptot pressure.>Gee-whiz, huh?>>Ed >>jimsury(at)fbtc.net________________________________________________________________________________
Pietenpol-List: RE: pitot tube size
Original Posted By: mikek(at)intex.net (Michael King)
On Saturday, February 21, 1998 6:50 PM, Jim Sury [SMTP:jimsury(at)fbtc.net] wrote:> I was just wondering what size tubing should be use for the pitot tube. I> was thinking of using stainless 1/4 inch tubing. Is this big enough. Should> I run two lines or is the static tube in the cockpit sufficient. Should> the tube be located in the leading edge or on the strut. I have seen them> in both locations. What are the advantages and disadvantages of each?> jas> jimsury(at)fbtc.netIn Addition to other good suggestions, might I add one about location. I put my Pahitoe(t) (just kidding) tube out through the leading edge. I wish that I would have routed it down to the strut. Every time I remove my wing I have to take special care not to damage or bend the pitot tube. Even now as the wings are off and stored in the saddles the pitot tube installed wing hangs too close to the floor for adequate clearance of the pitot tube. Just a word of caution to save you some grief. I also figured that I would be safe not running a static source out to the wing and just finding a place in or around the cockpit. I have tried under the seat, in the panel, through the cowling, everything but up my nose and still can't get a good spot. I may just have to retro the whole thing and come down the strut with both to solve the problem. In either position makeing sure you have a way to detatch and clean will save a lot of head-ache.Steve (learning the hard way) E________________________________________________________________________________
On Saturday, February 21, 1998 6:50 PM, Jim Sury [SMTP:jimsury(at)fbtc.net] wrote:> I was just wondering what size tubing should be use for the pitot tube. I> was thinking of using stainless 1/4 inch tubing. Is this big enough. Should> I run two lines or is the static tube in the cockpit sufficient. Should> the tube be located in the leading edge or on the strut. I have seen them> in both locations. What are the advantages and disadvantages of each?> jas> jimsury(at)fbtc.netIn Addition to other good suggestions, might I add one about location. I put my Pahitoe(t) (just kidding) tube out through the leading edge. I wish that I would have routed it down to the strut. Every time I remove my wing I have to take special care not to damage or bend the pitot tube. Even now as the wings are off and stored in the saddles the pitot tube installed wing hangs too close to the floor for adequate clearance of the pitot tube. Just a word of caution to save you some grief. I also figured that I would be safe not running a static source out to the wing and just finding a place in or around the cockpit. I have tried under the seat, in the panel, through the cowling, everything but up my nose and still can't get a good spot. I may just have to retro the whole thing and come down the strut with both to solve the problem. In either position makeing sure you have a way to detatch and clean will save a lot of head-ache.Steve (learning the hard way) E________________________________________________________________________________
Pietenpol-List: RE: pitot tube size
Original Posted By: Jim Skinner
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Pietenpol-List: RE: pitot tube size
Original Posted By: "Sayre, William G"
Steve E. wrote:> Just a word of caution to save you some grief. I also figured that I >would be safe not running a static source out to the wing and justfinding >a place in or around the cockpit. I have tried under the seat, in the >panel, through the cowling, everything but up my nose and still can'tget a >good spot. 0000,8080,8080I made the same decision Steve E.made and in May or June I get tofiddle with the same dilemma. Would a static port on the side of thefuselage like the factory planes have work or is that just good for other static instruments ? Also put my pitot in the wing LE butepoxied in a flush mounted 'receptacle making a bent probe replace-ment easy. Was a little extra work but...MC ________________________________________________________________________________
Steve E. wrote:> Just a word of caution to save you some grief. I also figured that I >would be safe not running a static source out to the wing and justfinding >a place in or around the cockpit. I have tried under the seat, in the >panel, through the cowling, everything but up my nose and still can'tget a >good spot. 0000,8080,8080I made the same decision Steve E.made and in May or June I get tofiddle with the same dilemma. Would a static port on the side of thefuselage like the factory planes have work or is that just good for other static instruments ? Also put my pitot in the wing LE butepoxied in a flush mounted 'receptacle making a bent probe replace-ment easy. Was a little extra work but...MC ________________________________________________________________________________
Pietenpol-List: Re: pitot tube size
Original Posted By: "David B. Schober"
Most of the Piets I've seen have the tube in the leading edge. If you are inthe building process, you may want to consider a fitting that allows theremoval of the tube along with an inspection hole.Steve Eldredge wrote:> On Saturday, February 21, 1998 6:50 PM, Jim Sury [SMTP:jimsury(at)fbtc.net]> wrote:> > I was just wondering what size tubing should be use for the pitot tube.> I> > was thinking of using stainless 1/4 inch tubing. Is this big enough.> Should> > I run two lines or is the static tube in the cockpit sufficient. Should> > the tube be located in the leading edge or on the strut. I have seen> them> > in both locations. What are the advantages and disadvantages of each?> > jas> > jimsury(at)fbtc.net>> In Addition to other good suggestions, might I add one about location. I> put my Pahitoe(t) (just kidding) tube out through the leading edge. I wish> that I would have routed it down to the strut. Every time I remove my wing> I have to take special care not to damage or bend the pitot tube. Even now> as the wings are off and stored in the saddles the pitot tube installed> wing hangs too close to the floor for adequate clearance of the pitot tube.> Just a word of caution to save you some grief. I also figured that I> would be safe not running a static source out to the wing and just finding> a place in or around the cockpit. I have tried under the seat, in the> panel, through the cowling, everything but up my nose and still can't get a> good spot. I may just have to retro the whole thing and come down the> strut with both to solve the problem. In either position makeing sure you> have a way to detatch and clean will save a lot of head-ache.>> Steve (learning the hard way) E--David B.Schober, CPEInstructor, Aviation MaintenanceFairmont State CollegeNational Aerospace Education CenterRt. 3 Box 13Bridgeport, WV 26330-9503(304) 842-8300________________________________________________________________________________
Most of the Piets I've seen have the tube in the leading edge. If you are inthe building process, you may want to consider a fitting that allows theremoval of the tube along with an inspection hole.Steve Eldredge wrote:> On Saturday, February 21, 1998 6:50 PM, Jim Sury [SMTP:jimsury(at)fbtc.net]> wrote:> > I was just wondering what size tubing should be use for the pitot tube.> I> > was thinking of using stainless 1/4 inch tubing. Is this big enough.> Should> > I run two lines or is the static tube in the cockpit sufficient. Should> > the tube be located in the leading edge or on the strut. I have seen> them> > in both locations. What are the advantages and disadvantages of each?> > jas> > jimsury(at)fbtc.net>> In Addition to other good suggestions, might I add one about location. I> put my Pahitoe(t) (just kidding) tube out through the leading edge. I wish> that I would have routed it down to the strut. Every time I remove my wing> I have to take special care not to damage or bend the pitot tube. Even now> as the wings are off and stored in the saddles the pitot tube installed> wing hangs too close to the floor for adequate clearance of the pitot tube.> Just a word of caution to save you some grief. I also figured that I> would be safe not running a static source out to the wing and just finding> a place in or around the cockpit. I have tried under the seat, in the> panel, through the cowling, everything but up my nose and still can't get a> good spot. I may just have to retro the whole thing and come down the> strut with both to solve the problem. In either position makeing sure you> have a way to detatch and clean will save a lot of head-ache.>> Steve (learning the hard way) E--David B.Schober, CPEInstructor, Aviation MaintenanceFairmont State CollegeNational Aerospace Education CenterRt. 3 Box 13Bridgeport, WV 26330-9503(304) 842-8300________________________________________________________________________________
Pietenpol-List: Re: pitot tube size
Original Posted By: "Richard F. Rapp"
Jim,I just used the double tube setup in Aircraft Spruce for my pitot staticsystem. It seems to work fine other than at high angles of attack.Craig________________________________________________________________________________
Jim,I just used the double tube setup in Aircraft Spruce for my pitot staticsystem. It seems to work fine other than at high angles of attack.Craig________________________________________________________________________________
Pietenpol-List: Re: pitot tube size
Original Posted By: DXLViolins(at)aol.com
When planning on the static scource, remember that when you place the sourcewithin the cockpit (at least on most aircraft), there is usually a lowerpressure within the cabin. Therefore, the instruments will read slightlydifferent from placement outside the aircraft. However, the instruments canand should be calibrated to whatever source you use for static. When anaircraft is used for instrument work and has an alternate static cource withinthe cockpit, a smart pilot checks what the differences are for both sourcesand makes a note of it for future reference. In our case, I don't know of anyIFR Piets, one source fits all, and once it is understood it can be usedwithout problems. A lot like swinging a compass. Once you have the deviationit is second nature to apply the needed correction.By the way, has anyone tried venting the static port to the area behind theengine and in front of the forward bulkhead? Or up into the center section? Ed________________________________________________________________________________
When planning on the static scource, remember that when you place the sourcewithin the cockpit (at least on most aircraft), there is usually a lowerpressure within the cabin. Therefore, the instruments will read slightlydifferent from placement outside the aircraft. However, the instruments canand should be calibrated to whatever source you use for static. When anaircraft is used for instrument work and has an alternate static cource withinthe cockpit, a smart pilot checks what the differences are for both sourcesand makes a note of it for future reference. In our case, I don't know of anyIFR Piets, one source fits all, and once it is understood it can be usedwithout problems. A lot like swinging a compass. Once you have the deviationit is second nature to apply the needed correction.By the way, has anyone tried venting the static port to the area behind theengine and in front of the forward bulkhead? Or up into the center section? Ed________________________________________________________________________________