TIGHAR
Amelia Earhart Search Forum => Aircraft & Powerplant, Performance and Operations => Topic started by: Brad Beeching on April 21, 2012, 08:05:45 PM
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I was just reading about the takeoff from Lae and was curious about the Bent Pitot (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/26_Antenna2/26_Antenna2.html) Tube.
The pitot tube is used to bring ambient air into the altimeter doesn't it?
Or is it used for the airspeed indicator?
Or both (2 tubes)?
Maybe someone has answered this before, but what could the effect be on the Electra?
If the hole in the tube is presented to the airstream as built, the instrument it is attached to will read as it was calibrated to read correct? Now, if that hole is presented to the airstream at an angle caused by a bent tube, the diameter of the hole in the pitot is in effect reduced is it not? What effect would that have on the flight? Would it have caused the airspeed indicator to read slow? How sensitive are the instruments of that era to damage of that type?
Sorry if this is redundant, I couldn't seem to find any discussion on the matter..
Brad
ps. I reread all of the link I provided and I answered some of my own questions, however since we have nothing better to do 'till July, I'll leave 'em to generate discussion..
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I was just reading about the takeoff from Lae and was curious about the Bent Pitot (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/26_Antenna2/26_Antenna2.html) Tube.
The pitot tube is used to bring ambient air into the altimeter doesn't it?
Or is it used for the airspeed indicator?
Or both (2 tubes)?
Maybe someone has answered this before, but what could the effect be on the Electra?
If the hole in the tube is presented to the airstream as built, the instrument it is attached to will read as it was calibrated to read correct? Now, if that hole is presented to the airstream at an angle caused by a bent tube, the diameter of the hole in the pitot is in effect reduced is it not? What effect would that have on the flight? Would it have caused the airspeed indicator to read slow? How sensitive are the instruments of that era to damage of that type?
Sorry if this is redundant, I couldn't seem to find any discussion on the matter..
Brad
ps. I reread all of the link I provided and I answered some of my own questions, however since we have nothing better to do 'till July, I'll leave 'em to generate discussion..
Simply put, as the pitot tube is responsible for providing the means of determining an aircraft's speed, and the speed of the aircraft has to be known so that proper utilisation of the fuel on board can be made then if the pitot is damaged and is providing erroneous information regarding speed such as a lower IAS than the actual then the pilot would be prompted to burn more fuel to bring the aircraft to the desired cruising speed/altitude. Obviously this would effect the actual distance the aircraft could fly by shortening its available range. Equally if the IAS was wrongly given as too high then the aircraft could be throttled back to be dangerously close to stalling speed. All sorts of nasty things can happen if the pitot tube is damaged.
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reply 932 page 65 some discussion on pitot tubes
https://tighar.org/smf/index.php/topic,571.960.html
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reply 932 page 65 some discussion on pitot tubes
https://tighar.org/smf/index.php/topic,571.960.html (https://tighar.org/smf/index.php/topic,571.960.html)
Also see my prior post here (https://tighar.org/smf/index.php/topic,571.msg10273.html#msg10273).
gl
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Yes a bent pitot tube will give erroneous information regarding airspeed. Even these days airliners fall foul of false information fed to the computers by faults related to the pitot tubes. Garys explanation regarding the fuel consumption errors associated with such a problem are significant in AE's case.
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In reading about the Bent Pitot Tube (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/26_Antenna2/26_Antenna2.html), it states that the tube(s) provided ram air to the airspeed indicators. And if it were bent, it would make that indicator read slower? Can we know from the angle of the tube how much slower that indicator might have been off?
So if she had one indicator that was reading slower, and the other (being undamaged) we'll assume is correct. If she looked at both indicators and saw one was a bit off, how much does that effect her piloting?
Brad
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If she looked at both indicators and saw one was a bit off, how much does that effect her piloting?
Brad
Rather depends on how distorted the inside of the tube was, if it was bent, and that is rather impossible to tell at this distance in time.
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I rather expected as much. It was just curiosity. I've been trying to grasp the picture of the disappearance as a whole. It appears there was alot of damage to the airplane that impacted her ability to find Howland. It wasn't just that she didn't understand Morse Code, or was just stubborn or that she just held a course too far one way or another. One bit seems to have compounded another and impacted another and so on and so on, until the airplanes flew away and she knew, I mean really knew that no one would be coming.
Brad
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We spent a lot of bandwidth on this once upon a time, and , if memory serves, it was finally determined through forensic imaging analysis of the photo and take off film by none other than Jeff Glickman that that pitot tube was not bent or damaged as it appears. More of an optical illusion brought on by the angle of the photo or something like that.
See the update at the top of the research bulletin on the Lost Antennahttp://tighar.org/Projects/Earhart/Archives/Research/Bulletins/26_Antenna2/26_Antenna2.html (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/26_Antenna2/26_Antenna2.html)
Update, 11/25/01
Subsequent analysis by Photek has determined that the “bent” pitot tubes are an optical illusion and were, in fact, undamaged at the time of takeoff. The conclusion that the belly antenna is missing remains unchanged.
Andrew
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I rather expected as much. It was just curiosity. I've been trying to grasp the picture of the disappearance as a whole. It appears there was alot of damage to the airplane that impacted her ability to find Howland. It wasn't just that she didn't understand Morse Code, or was just stubborn or that she just held a course too far one way or another. One bit seems to have compounded another and impacted another and so on and so on, until the airplanes flew away and she knew, I mean really knew that no one would be coming.
I think that is what people mean when they talk about an "accident chain." (http://www.pilotjourney.com/accident-chain/) Hindisight is 20-20 vision. After 12 years of reading about TIGHAR's work, I feel confident that the major links in this chain have been found.
If one link in the chain had been removed, the chain would have broken.
Small things add up. "The devil is in the details."
The hard part is recognizing an accident chain before the accident happens. I drove a car off the road and into a retaining wall in November. I wish I could have that night back with the benefit of hindsight. :(
Here's the last link in my accident chain, for inquiring minds and safety-conscious drivers: don't use cruise control on slippery roads. If anybody ever mentioned that to me, I wasn't listening. I took driver's ed in 1966, and the proper use of cruise control was not on our curriculum because the device wasn't available in most of the cars on the road back then. ::)
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Update, 11/25/01
Subsequent analysis by Photek has determined that the “bent” pitot tubes are an optical illusion and were, in fact, undamaged at the time of takeoff. The conclusion that the belly antenna is missing remains unchanged.
Mr. McKenna, I didn't see where the bulletin was updated, is that info somewhere else perhaps? Or did I just miss it? In any case, thats one heck of an illusion! ;D
for inquiring minds and safety-conscious drivers: don't use cruise control on slippery roads.
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
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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.
BTDT and agree that that is the best technique for an emergency stop.
I've been driving on ice and snow in the Northeast since 1968. As a general rule, I don't use the breaks when trying to correct a skid. It wasn't until hours after the accident that I could answer the question why everything I did made the fishtailing worse rather than better. Answer: the cruise control was driving the wheels at the equivalent of 65 mph while the the car's groundspeed was less than that. Of course, if I hadn't been distracted by finishing a cup of coffee and trying to figure out the lyrics of a song on the radio, I probably wouldn't have lost control of the car in the first place. That's the dumb thing about accidents. They happen when I don't expect them. :-[
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The research bulletin is dated August 10, 2000
Look right at the top of the page http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/26_Antenna2/26_Antenna2.html (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/26_Antenna2/26_Antenna2.html)
and you should see the box that has the update
Update, 11/25/01
Subsequent analysis by Photek has determined that the “bent” pitot tubes are an optical illusion and were, in fact, undamaged at the time of takeoff. The conclusion that the belly antenna is missing remains unchanged.
amck
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::) Well.... there you go... if you want to hide something from me.... put it right out in front where everyone else can see it!
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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 (http://voices.yahoo.com/plane-crashes-pitot-tubes-2447529.html)
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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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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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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 (http://voices.yahoo.com/plane-crashes-pitot-tubes-2447529.html)
The B-2 crash was on Guam and you can see the video here. (http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0CEIQtwIwAw&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D8ZB-iziY2Bw&ei=hniUT865IeajiQLL05EW&usg=AFQjCNGd6zSPAL8e-4InA_SIHn9a3OuKRg&sig2=dGkrzuTx0e50WrALRNZHvA)
A Boeing 757 went down for the same reasons off of the Dominican Republic (http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=0CHIQFjAH&url=http%3A%2F%2Faviation-safety.net%2Fdatabase%2Frecord.php%3Fid%3D19960206-0&ei=3HiUT66nG4fmiALl0sgO&usg=AFQjCNFGJ1PabV01NQI1oFLoxzwwnTZQYg&sig2=Y5CK9S8oYuDGAJiDw6JY4Q).
Another B-757 crashed in the ocean offshore of Lima Peru (http://aviation-safety.net/database/record.php?id=19960206-0) 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. (http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CDkQFjAA&url=http%3A%2F%2Fen.wikipedia.org%2Fwiki%2FAir_France_Flight_447&ei=eHqUT4lsz8-IAruo1NsP&usg=AFQjCNHCkMf3o1_AECcMbbH9rcAwftI0Mw&sig2=HCRDRO-I-ovK9vHIZGuy3w)
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
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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.
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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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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 (http://tighar.org/smf/index.php/topic,1202.0.html)?
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Can anyone please identify the function of the component referenced in the attached photo?
Thanks.
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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.
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Yep, Jeff is correct and one mell-of-a-hess to change out. Been there done that!
Ted Campbell
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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.
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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...