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Jeff J
 Post subject: Re: Retrofit Pitot Tube
PostPosted: Mon Jun 25, 2018 10:50 am 
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It looks like we lost the pictures in this thread right when I was getting serious about moving the pitot tube. Would you guys be willing to repost them?

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson


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Jeff J
 Post subject: Re: Retrofit Pitot Tube
PostPosted: Tue Jun 26, 2018 7:28 am 
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Nevermind, I found a work around and downloaded the pictures.
viewtopic.php?f=29&t=8239

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson


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Jeff J
 Post subject: Re: Retrofit Pitot Tube
PostPosted: Thu Jul 26, 2018 11:30 am 
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I finally installed a blade type pitot tube on the wing. I was pleasantly surprised at how easy removing the old pitot tube was. Disconnect the lines, remove 2 screws and lift it out of the fin. Since I have a T-18 with the original wing, I opted to install the blade behind the left aileron bellcrank. That puts it well outside the prop arc and kept me from needing to plumb anything to the outer wing. I connected the static line to a pair of ports located behind the cockpit per an article I found in the news letters. I checked the ASI against the GPS by taking an average of my ground speed over 4 passes and 4 different directions and was very happy with the results (average ground speed was 152.25 mph while ASI read ~152 during all 4 passes). I never checked the old system.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson


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Binder
 Post subject: Re: Retrofit Pitot Tube
PostPosted: Thu Jul 26, 2018 7:52 pm 
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Jeff J wrote:
I finally installed a blade type pitot tube on the wing. I was pleasantly surprised at how easy removing the old pitot tube was. Disconnect the lines, remove 2 screws and lift it out of the fin. Since I have a T-18 with the original wing, I opted to install the blade behind the left aileron bellcrank. That puts it well outside the prop arc and kept me from needing to plumb anything to the outer wing. I connected the static line to a pair of ports located behind the cockpit per an article I found in the news letters. I checked the ASI against the GPS by taking an average of my ground speed over 4 passes and 4 different directions and was very happy with the results (average ground speed was 152.25 mph while ASI read ~152 during all 4 passes). I never checked the old system.



I would like to see some pics on how you did it. That is what I would like to do in order to remove that weird prop wash to my pitot along with the loss of pitot due to high angle of attack on final. Anything below about 75mph my a/s is worthless.


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Jeff J
 Post subject: Re: Retrofit Pitot Tube
PostPosted: Fri Jul 27, 2018 5:41 pm 
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Location: eastern OK
Look at Tony’s pictures for the bracket. He did a much better job than I did. I had to form mine over a bucking bar with a mallet and it shows how little experience I have working that way. I riveted the mount to the rib behind the left aileron bellcrank. I had to install an inspection panel (bought from Cubes) and remove the outer wing to do the work. I was able to remove and reinstall the outer wing unassisted. I had considered trying panel bond but the convenience didn’t out weigh the cost for me. It looked like it was going to be $100 for the small tube of epoxy with the application gun plus no one local carries it. All of rivets for the job cost less than ten cents and I have hundreds on hand.

Image

Image

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson


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Binder
 Post subject: Re: Retrofit Pitot Tube
PostPosted: Sun Jul 29, 2018 9:43 am 
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I remember Tony’s pictures but I can’t get them to work. They are x’ed out on the site.


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Jeff J
 Post subject: Re: Retrofit Pitot Tube
PostPosted: Sun Jul 29, 2018 4:56 pm 
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Location: eastern OK
This should work:
https://postimg.cc/image/bnua663c5/

_________________
Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson


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Binder
 Post subject: Re: Retrofit Pitot Tube
PostPosted: Mon Jul 30, 2018 5:46 pm 
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Posts: 245
thank you! I just saw your thread on the .cc change on the images.


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Jeff J
 Post subject: Re: Retrofit Pitot Tube
PostPosted: Tue Jul 31, 2018 3:44 pm 
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Location: eastern OK
Here are shots of the new static ports:


Attachments:
87840677-D95A-4AC8-AB5C-AFDBB2AB7D50.jpeg
87840677-D95A-4AC8-AB5C-AFDBB2AB7D50.jpeg [ 1.42 MiB | Viewed 320 times ]
CA05F50E-4F6D-47B2-B20A-76E776292353.jpeg
CA05F50E-4F6D-47B2-B20A-76E776292353.jpeg [ 1.02 MiB | Viewed 320 times ]
7923ACEC-7B9E-4B7C-8505-A5FD49CBE3CB.jpeg
7923ACEC-7B9E-4B7C-8505-A5FD49CBE3CB.jpeg [ 962.26 KiB | Viewed 320 times ]

_________________
Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson
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James Grahn
 Post subject: Re: Retrofit Pitot Tube
PostPosted: Wed Aug 01, 2018 9:39 am 
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Joined: Sat Oct 24, 2009 7:16 pm
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Jeff,
Nice work. I'm sure you know this, but make sure the static line rises inside the fuselage so you don't get water stuck in it.
Cubes


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Jeff J
 Post subject: Re: Retrofit Pitot Tube
PostPosted: Wed Aug 01, 2018 10:23 am 
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Joined: Wed Aug 31, 2016 8:18 am
Posts: 401
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Location: eastern OK
Good eye! The way I have it now, water can collect between the 2 ports but not gravity flow forward so the left side "should" always be clear. However, I have access to some salvaged Cessnas and I thought I might eventually raid them for their static line sumps but I like your idea better. It is easier to do and I don't have to wade through poison ivy and/or briars to do it. Thanks

_________________
Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson


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 Profile Personal album  
 
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