TimePilot
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Tri-motor - What's That On The Wing?

Thu Nov 09, 2006 8:50 am

In this photo here: http://www.aviaprints.com/images/birds/AP001-S-Ford-Tri-Motor-413.jpg (Sorry, I don't have my own photo.)

What is that small tube-like thing sticking out and down of the left wing? (far right side of the photo.) Is that for measuring air speed?
 
Goldenshield
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RE: Tri-motor - What's That On The Wing?

Thu Nov 09, 2006 8:57 am

If I remember correctly from reading various things on sailplanes, it's there to provide a more rapid response from the pitot-static system on the static side, i.e.; the VSI will respond much faster here than in a standard pitot-static setup, which, for a sailplane, will allow the pilot to guage whether or not he is in an area of lift more accurately. I'm not sure what it's called, though.
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SlamClick
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RE: Tri-motor - What's That On The Wing?

Thu Nov 09, 2006 8:58 am

Appears to be the pitot tube, indeed it does measure airspeed. As the Ford Trimotor hurtles through the air at speeds unmatched by anything but maybe a 1951 Studebaker pulling a horse trailer over the Grapevine, air is rammed into the open forward end of that tube and the resultant pressure reads as airspeed.

Search online for "pitot tube" images for schematics and so forth.

The Ford Trimotor holds a distinction. A flight from San Francisco to Reno back in the 20s flew at cruise speed into the top of a hill down near Auburn California - without any serious injuries.

Well, there might have been some, you know, spilled coffee etc.
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KPIE172
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RE: Tri-motor - What's That On The Wing?

Thu Nov 09, 2006 8:59 am

Could it be a fuel overflow port? Seeing as it angled downward it looks like it wouldn't provide accurate direct air pressure for airspeed. Although it seems like it would be a good place for the pitot tube (out of the way of the prop wash).

Not sure though, I'm sure someone knows the right answer!

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KELPkid
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RE: Tri-motor - What's That On The Wing?

Thu Nov 09, 2006 8:59 am

Quoting TimePilot (Thread starter):
What is that small tube-like thing sticking out and down of the left wing? (far right side of the photo.) Is that for measuring air speed?

Sure looks like a Pitot Tube to me... The Pitot Tube is indeed where the airspeed indicator reading comes from (the "Ram" pressure component at least!). I'm no tri-motor expert, however.
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Starlionblue
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RE: Tri-motor - What's That On The Wing?

Thu Nov 09, 2006 9:11 am

Quoting SlamClick (Reply 2):

The Ford Trimotor holds a distinction. A flight from San Francisco to Reno back in the 20s flew at cruise speed into the top of a hill down near Auburn California - without any serious injuries.

Well, there might have been some, you know, spilled coffee etc.

Oh the humanity! Big grin
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Goldenshield
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RE: Tri-motor - What's That On The Wing?

Thu Nov 09, 2006 9:13 am

Found it. It's called a "total energy probe," which is a variation of a pitot tube.

Picture of a variant here:

http://www.whiteplanes.com/images/showcase/toyota/toyota7.jpg
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Fly2HMO
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RE: Tri-motor - What's That On The Wing?

Thu Nov 09, 2006 10:27 am

A close up:



Its a pitot tube for sure, but don't know why you'd want a total energy probe in a trimotor....

Maybe the bottom thingy is a static port?
 
atct
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RE: Tri-motor - What's That On The Wing?

Thu Nov 09, 2006 10:56 am

Looks like a Static Port/Pitot Tube combo. (I believe Piper Warrior's have a similar device...but square...been a while since ive flown one).


ATCT
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Jetlagged
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RE: Tri-motor - What's That On The Wing?

Thu Nov 09, 2006 11:32 am

Quoting KPIE172 (Reply 3):
Seeing as it angled downward it looks like it wouldn't provide accurate direct air pressure for airspeed.

It's angled down so that it is better aligned with local airflow. Placing it well forward of the leading edge will also provide more accurate readings. Ford clearly wanted it to read as many knots as it possible.  Smile
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Buzz
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RE: Tri-motor - What's That On The Wing?

Thu Nov 09, 2006 8:53 pm

Hi Jetlagged, Buzz here. Well, if they wanted higher numbers then Henry Ford (or was it Mr. Edsel?) should calibrate the Airspeed in MPH instead of Knots. Back in the 1920's not many people over here uses kilometers per hour, but that would have given a significant boost in speed (grin)

Several 1930's airplanes had that 2 stage pitot probe. I haven't taken one apart so far. I guess it's out of the "local flow" from the props and nacelles up there.

g'day
 
TimePilot
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RE: Tri-motor - What's That On The Wing?

Sat Nov 11, 2006 12:01 pm

Thanks for everyone's answers  Smile

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