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Author Topic: Bent Pitot Tube  (Read 27157 times)

Jeff Victor Hayden

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Re: Bent Pitot Tube
« Reply #15 on: April 22, 2012, 01:30:05 PM »

Experimental tests (Dunn and Wade, 1994) determined the following mechanisms that can affect aircraft performance due to exposure to a volcanic ash cloud:

(a) Deposition of material on hot-section components.
(b) Erosion of compressor blades and rotor-path components.
(c) Blockage of fuel nozzles and cooling passages.
(d) Contamination of the oil system and bleed-air supply.
(e) Opacity of windscreen and landing lights.
(f) Contamination of electronics.
(g) Erosion of antenna surfaces.
(h) Plugging of the pitot-static system which indicates the airspeed of the aircraft.


There was volcanic activity in the Raboul area from may 1937 to ?
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Gary LaPook

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Re: Bent Pitot Tube
« Reply #16 on: April 22, 2012, 02:37:52 PM »


Mr. Moleski, Here is something else not taught in driving schools. If you are on ice in an automatic, kick it out of drive when you need to stop. Automatics seem to keep "driving" even when the brakes are applied. Try it next winter in a safe place, you'll be surprised at how fast you can stop.

Brad
Having driven in ice and snow in the Chicago area for 25 years I really appreciated the safety advantage of a manual transmission. Just stepping on the clutch allows the wheels to synchronize with the road so making them less likely to continue with the skid. And also, a more mundane advantage, you are much more effective in rocking the car to get unstuck in the deep snow or mud since you get much quicker response with the use of the clutch than trying to shift from drive to reverse so you can get the timing right to increase the amplitudes of the swings and get out,

gl
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Gary LaPook

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Re: Bent Pitot Tube
« Reply #17 on: April 22, 2012, 03:37:49 PM »

Brad, here's a link that shows some of the problems associated with pitot tubes and their consequences. There's a lot of these incidents on aircrash investigation on youtube...

http://voices.yahoo.com/plane-crashes-pitot-tubes-2447529.html
The B-2 crash was on Guam and you can see the video here.

A Boeing 757 went down for the same reasons off of the Dominican Republic.

Another B-757 crashed in the ocean offshore of Lima Peru due to tape left covering the static sources to keep water out while the plane was washed that was was missed on the preflight inspection.

The most recent example of this is the Air France crash in 2009.

These are just the tip of the iceberg, there are many, many accidents due to problems with the pitot static system.

None of these accidents had to happen (except, maybe, the B-2 since that plane was almost completely computer controlled) if the pilots had just used normal piloting skills. When you realize you have inaccurate airspeed indicators a pilot should say to himself "the ASI is wrong so I will ignore it (cover it up with a piece of paper if possible) and I WILL FLY ONLY BY THE ATTITUDE INSTRUMENTS!" Roll the wings level, put the nose on the horizon in the attitude indicator, set a reasonable power setting and sort things out later.

See attached Aviation Week and Space Technology article.

gl
« Last Edit: April 22, 2012, 04:01:43 PM by Gary LaPook »
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Jeff Victor Hayden

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Re: Bent Pitot Tube
« Reply #18 on: April 22, 2012, 04:50:55 PM »

Attaching the belly antenna to one of the pitot tubes was an accident waiting to happen (even if it didn't). I can't see the FAA or the CAA endorsing that sort of design these days.
This must be the place
 
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Jeffrey Donald Shaffer

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Re: Bent Pitot Tube
« Reply #19 on: July 01, 2013, 11:00:06 AM »

Hi folks. In an effort to support the bent pitot tube discussion presented in the Earhart Project Research Bulletin of
August 10, 2000, I have submitted my own photo interpretation for consideration. I have annotated the photo of the Lae takeoff and would like to know if anyone agrees with me. This, of course, is my own opinion. I believe I see the state of both pitot tubes - the left one can be delineated by a visible shadow along the verticle leading edge of the tube body and the lower "heel" of the bent, right pitot tube can be seen extending beyond the trailing edge of the left pitot along with the angled leading edge appearing on the far side of the left tube. A heavy gauge antenna wire might easily cause this to occur with the antenna assembly being ripped off during the takeoff run.
    I realize this subject has been thoughly discussed before hand, and pray I'm not beating a dead horse into the ground, but I appreciate the opportunity to add a few words to the project. Thanks, Jeff Shaffer
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Doug Giese

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Re: Bent Pitot Tube
« Reply #20 on: July 02, 2013, 08:07:57 PM »

Hi folks. In an effort to support the bent pitot tube discussion presented in the Earhart Project Research Bulletin of
August 10, 2000, I have submitted my own photo interpretation for consideration .. (snip).. Thanks, Jeff Shaffer

When Jeff Shaffler's post was moved from New Member Introductions, an important part of his qualifications remained in that section:

"I was an imagery/air photo interpreter in the U.S.A.F. and with all due respect to the professional talents at Photek, I saw something different."

I'd appreciate hearing additional information other than provided by Jeff Glickman. What do you see in The Cook photo?
------
Doug
 
« Last Edit: July 02, 2013, 08:33:23 PM by Doug Giese »
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Tim Mellon

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Re: Bent Pitot Tube
« Reply #21 on: October 24, 2013, 09:42:15 AM »

Can anyone please identify the function of the component referenced in the attached photo?

Thanks.

Tim
Chairman,  CEO
PanAm Systems

TIGHAR #3372R
 
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JNev

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Re: Bent Pitot Tube
« Reply #22 on: October 24, 2013, 10:36:07 AM »

Can anyone please identify the function of the component referenced in the attached photo?

Thanks.

That is the oil scavange pump housing. 

Radials like these have 'dry sump' arrangements, not 'oil pan' type reservoirs.  Oil is supplied from a remote tank in the nacelle and forced through the vitals of the engine, including typically spray lubrication of roller bearings, etc. 

What you are seeing is part of the means of internally recovering that oil once it has passed through the crankshaft bearings, lower rocker covers, etc. and then gravity drains it to the lower end of that 'tower'; there a set of gear pumps recovers the oil by motivating it back to the return side of the oil tank. 

The pump is shaft driven and has about twice the capacity of the pressure pump that feeds the engine to ensure complete recovery, or a continuous 'dry sump' during operation.
- Jeff Neville

Former Member 3074R
 
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Ted G Campbell

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Re: Bent Pitot Tube
« Reply #23 on: October 24, 2013, 01:38:34 PM »

Yep, Jeff is correct and one mell-of-a-hess to change out.  Been there done that!
Ted Campbell
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John Balderston

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Re: Bent Pitot Tube
« Reply #24 on: October 24, 2013, 09:55:10 PM »

Can anyone please identify the function of the component referenced in the attached photo?

Thanks.

It's so cool to look at that picture of a P&W Wasp and no cowling, and a two-bladed propeller.  You can almost hear it flying over your head at 1000 ft.  2200 rpm x 2 blades / 60 = 73 Hz.  Anyone with a piano, walk on over and plunk the first D and there you have it.  Thanks Tim, and apologies for thread drift.
John Balderston TIGHAR #3451R
 
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JNev

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Re: Bent Pitot Tube
« Reply #25 on: October 25, 2013, 04:02:39 AM »

Can anyone please identify the function of the component referenced in the attached photo?

Thanks.

It's so cool to look at that picture of a P&W Wasp and no cowling, and a two-bladed propeller.  You can almost hear it flying over your head at 1000 ft.  2200 rpm x 2 blades / 60 = 73 Hz.  Anyone with a piano, walk on over and plunk the first D and there you have it.  Thanks Tim, and apologies for thread drift.

Well agreed, John - "poetry in motion"... well, maybe not as elegant as the topic of that song, but certainly a symphony in D as you say...

Drift... I guess I was so captivated that I overlooked it - BAD moderator!  I guess I can split this into its own well-deserved string.

Yes, thanks Tim - you made me recall days in '76 - '78 at A&P school at a WWII era hangar on Souther Field in Americus, GA with two old navy C-45's ('twin Beech' or "18" models) that I got well greased on from overhaul to ground runs.  I wonder if my uncle actually flew one of those two birds... wish I had looked that up. 

My power plant instructor was a heck of a great fellow - great teacher and like a father to many of us who were young and 'far from home' (seemed like it then).  He wore a belt buckle with that same lovely Pratt & Whitney eagle on it very often.  I can still remember him talking over my shoulder while I was learning to use a timing tool on those 985's - well, talking from the ground while I was on a work stand to reach the master rod cylinder to get the 'Time-Rite' set up... and I remember him talking me through my first engine start on that bird - and gently helping coax it to life by moving the 'shiny knobs' in wizard-like ways after 'six blades and mags on' - and then that lovely starter whine and chug yielded up those lovely belches of first combustion - and then she would come to that 'D' drumming John mentioned as a shaky engine 'took' and settled in... takes me back.

Just to add a bit MORE drift before moving on - Souther Field in Americus is where Charles Lindbergh bought his first Jenny and soloed not long after WWI. 

I spent quite a bit of time roaming the woods there back then before the 'modern' airport pushed all that out and away - lots of Waco glider bones back there and other old stuff I never did identify.  Long years before I knew anything about TIGHAR - too bad, I think Ric might have enjoyed picking through those weeds before that stuff got raked out for scrap.  I salvaged a few things - six old WWII era airport runway marker 'cones' (huge) - they are the primary markers on our private strip to this day; a control yoke from a GI glider - lower cross-tube and left vertical 'stick' with a mostly still intact wooden control wheel attached.  It hangs on my dad's hangar wall to this day out on our grass strip - I thought it was a fitting keep-sake for an old army airborne special forces vet who served in the CBI theatre in WWII.  I'll try to get some pictures this weekend and post them in case anyone cares about that kind of stuff.

Sorry for the drift and day dreaming, but this stuff really does get into your blood after a while...
- Jeff Neville

Former Member 3074R
 
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