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Amelia Earhart Search Forum => Aircraft & Powerplant, Performance and Operations => Topic started by: Sheila Shigley on October 22, 2011, 09:42:06 AM
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The XC-35 was delivered to Wright Field, Ohio in May 1937, made its first performance flight on August 5, and was involved in an extensive flight testing program for which the Army Air Corp [sic] was awarded the Collier Trophy. The lessons learned from the XC-35 played a key role in the development of the Boeing 307 and the B-29 Superfortress which was to be the first mass produced pressurized aircraft. (Van Patten, Robert E., Air Force Magazine Online, Vol.86, No.1 January 2003)
I find it curious that the Army Air Corps was involved in vigorous testing of a model 10 Electra--dual high-priority testing for a technology of revolutionary military and civilian significance; further, that this technology was rolled out eight weeks before AE's flight and then announced a "first performance flight" four weeks after her loss.
Is it possible that Bob Wemple (or someone) modded AE's Electra to a "10-E" not by installing Pratt & Whitney R-1340 Wasp S3H1, 600 hps, but turbocharged Pratt & Whitney XR-1340-43, 550 hps? (Can we tell from existing data whether she used 600s or 550s?)
Would it have been worth testing the turbos on this flight without making any other mods (other than the actual ones necessary to use those specific engines instead of the S3H1s)? I.e. no cabin pressurization, etc., simply an engines test?
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I find it curious that the Army Air Corps was involved in vigorous testing of a model 10 Electra--dual high-priority testing for a technology of revolutionary military and civilian significance; further, that this technology was rolled out eight weeks before AE's flight and then announced a "first performance flight" four weeks after her loss.
I don't find it at all curious. The creation of variants is perfectly normal with aircraft design.
Is it possible that Bob Wemple (or someone) modded AE's Electra to a "10-E" not by installing Pratt & Whitney R-1340 Wasp S3H1, 600 hps, but turbocharged Pratt & Whitney XR-1340-43, 550 hps? (Can we tell from existing data whether she used 600s or 550s?)
Anything is possible.
The documentation says that she had Wasp S3H1 engines. Various sites give various horsepower figures, ranging from 550 to 650 HP.
Would it have been worth testing the turbos on this flight without making any other mods (other than the actual ones necessary to use those specific engines instead of the S3H1s)? I.e. no cabin pressurization, etc., simply an engines test?
Turbochargers were invented in 1905. It was old technology by 1937. Engineers would want to test under controlled conditions. I can't imagine that they would ask AE to do engine testing for them.
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I think it wouldn't have been to test the turbos as a separate technology but rather their performance with this particular airframe.
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The XC-35 was delivered to Wright Field, Ohio in May 1937, made its first performance flight on August 5, and was involved in an extensive flight testing program for which the Army Air Corp [sic] was awarded the Collier Trophy. The lessons learned from the XC-35 played a key role in the development of the Boeing 307 and the B-29 Superfortress which was to be the first mass produced pressurized aircraft. (Van Patten, Robert E., Air Force Magazine Online, Vol.86, No.1 January 2003)
I find it curious that the Army Air Corps was involved in vigorous testing of a model 10 Electra--dual high-priority testing for a technology of revolutionary military and civilian significance; further, that this technology was rolled out eight weeks before AE's flight and then announced a "first performance flight" four weeks after her loss.
Is it possible that Bob Wemple (or someone) modded AE's Electra to a "10-E" not by installing Pratt & Whitney R-1340 Wasp S3H1, 600 hps, but turbocharged Pratt & Whitney XR-1340-43, 550 hps? (Can we tell from existing data whether she used 600s or 550s?)
Would it have been worth testing the turbos on this flight without making any other mods (other than the actual ones necessary to use those specific engines instead of the S3H1s)? I.e. no cabin pressurization, etc., simply an engines test?
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Are you sure that the R-1340-43 was turbocharged? It appears to have had the same mechanical supercharger as the other Wasps with an impeller ratio of 8:1. See attached document of P&W engine designations.
gl
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Sites list the XR-1340-43s as "supercharged," "turbo-supercharged" and "turbocharged."
National Museum USAF gives:
The XC-35 was fitted with a pair of Pratt & Whitney XR-1340 radial engines. These 550-hp engines were turbo-supercharged to deliver the necessary high-altitude performance.
http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?fsID=3296
Nearly all sites list one XC-35 being built; anecdotally there is discussion of two having been built but we'll need something more than anecdotes to get to the bottom of that rumor.
(http://farm5.static.flickr.com/4092/4962628566_8ddbbbcebf_b.jpg)
A whole bunch of sweet XC-35 photos:
http://www.nationalmuseum.af.mil/factsheets/factsheet_media.asp?fsID=3296
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Incidentally, XC-35 lists crew of three (the third guy had to run the pressurization system and high-altitude test equipment).
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we'll need something more than anecdotes to get to the bottom of that rumor.
The rumor is just an anecdote. We have already gotten to the bottom of it by citing documents that show that AE's engines were not changed.
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Clarence "Kelly" Johnson
Johnson (1910-1990) created innovative technical concepts that significantly advanced aircraft design, performance and reliability. Johnson helped design 40 of the world's top aircraft, including the Lockheed P-38 "Lightnings;" the model 10 "Electra" used by Amelia Earhart; the XC-35, the first successful pressurized cabin plane in 1936; and the "Super Electra" used by Howard Hughes to set a record-smashing flight around the world. He also designed the U-2 and SR-71 "Blackbird" which made a non-stop flight from New York to London in 1 hour, 55 minutes.
[I'm sure this is not new to any of you, but wanted to include it in the thread for background.]
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(http://rbogash.com/Kelly_HowardThompson.jpg)
Kelly Johnson working in Flight Test during Model 10 Electra testing - c. late 1930s
http://rbogash.com/kelly.html
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Am curious why there were rumors of a 2nd.
There weren't. At least not until the 1970s.
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I think it wouldn't have been to test the turbos as a separate technology but rather their performance with this particular airframe.
To get that data, they fly around in the vicinity of home base, keeping track of all of the relevant variables (air pressure, temperature, humidity, prop settings, manifold pressure, air speed, elapsed time, altitude, etc.), then draw up tables to use for flight planning. They don't send two non-engineers around the world to see how the new toys run.
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They don't send two non-engineers around the world to see how the new toys run.
I wouldn't presume the flight was a ruse, but rather that the new toys were serving his XC-35 so well that Kelly might have considered the turbos an equally good or superior option for his (AE's) 10-E. One of the 35's goals was endurance, and that attribute would certainly serve AE well, though I'm not sure how the high-altitude goal (of the 35) factors in. Most refs to the turbo aspect of the 35 mention its facilitating high-altitude flight.
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They don't send two non-engineers around the world to see how the new toys run.
I wouldn't presume the flight was a ruse, but rather that the new toys were serving his XC-35 so well that Kelly might have considered the turbos an equally good or superior option for his (AE's) 10-E.
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In what way? Her S3H1 engines put out more power and their mechanical superchargers provided all the altitude performance they could use without pressurization or oxygen. It does appear that the plane did have turbochargers in addition to the mechanical superchargers to provide additional altitude capability and to provide bleed air for the pressurization system as this photo shows one on the outboard side of the right nacelle, its the circular object. No such turbocharger appears in any of the photos of Earhart's plane.
http://en.wikipedia.org/wiki/File:Lockheed_XC-35.jpg
gl
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They don't send two non-engineers around the world to see how the new toys run.
I wouldn't presume the flight was a ruse, but rather the new toys might at that point have been running so well on his XC-35, that Kelly might have considered the turbos an equally good or superior option for his (AE's) 10-E.
Maybe.
Maybe not.
I can't find the purchase order or bill of sale for the Electra. I saw it somewhere online in the last year or so. AE paid for all of the work done on her aircraft. KJ may have been in love with the PRATT and WHITNEY engines (purchased from PRATT and WHITNEY, not produced by Kelly Johnson or Lockheed), but I doubt that he donated two of them to AE out of the kindness of his heart.
I can't deny that KJ or Lockheed or the U.S. gummint might have done so. It's not a self-contradictory concept (such as that of trisecting an angle using only a compass and straight edge), so it is in the real of possibility.
All of the documentary evidence suggests that the Electra was not equipped with super-secret super-powerful engines. That you can imagine that the truth might be otherwise--and might have been covered up by all of the people involved in the installation--is not documentary evidence.
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Sorry Gary - I edited just as you were posting.
I'm still trying to find how the turbo factors in, although it seems to not be in question that the XC-35 used turbo (most of the info sites mention it and/or the turbo's specific benefit at high altitudes).
Is it possibly the difference between the R-1340 and XR-1340 designation?
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It looks as if while the civvie engines would include a T (if turbocharged) the military designations wouldn't. Civilian TSC4-G16:9 is military R-1830-43.
If the -43 is partly what reflects the turbo (I don't know that it is), then the XR-1340-43 designation seems in line with that convention...here's a doc in the meanwhile:
http://www.enginehistory.org/P&W/PWdesignations.pdf
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From Part Number Explanations at enginehistory.org:
Stromberg Model : NA-Y9E-2
Part No.: P/W# 22115
Engine Application: R-1340-43
Date: 1937
Notes: Army carb, No self prime, Idle cutoff, Manual mixture control
Also lists specs for S3H1.
www.enginehistory.org/Carbs/CarbApps_05.xls
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It looks as if while the civvie engines would include a T (if turbocharged) the military designations wouldn't. Civilian TSC4-G16:9 is military R-1830-43.
If the -43 is partly what reflects the turbo (I don't know that it is), then the XR-1340-43 designation seems in line with that convention...here's a doc in the meanwhile:
http://www.enginehistory.org/P&W/PWdesignations.pdf
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Why do you think TSC4-G is the civilian designation of the R-1340-43? The "-G" indicates a geared engine while the -43 engine was direct drive.
gl
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Why do you think TSC4-G is the civilian designation of the R-1340-43? The "-G" indicates a geared engine while the -43 engine was direct drive.
Civilian TSC4-G16:9 is military R-1830-43 (acc. to http://www.enginehistory.org/P&W/PWdesignations.pdf - but I haven't looked up additional sources to confirm this.)
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Why do you think TSC4-G is the civilian designation of the R-1340-43? The "-G" indicates a geared engine while the -43 engine was direct drive.
Civilian TSC4-G16:9 is military R-1830-43 (acc. to http://www.enginehistory.org/P&W/PWdesignations.pdf - but I haven't looked up additional sources to confirm this.)
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You read that too quickly. It refers to the R-1830-43 Twin Wasp not the R-1340 -43 Wasp. The 16:9 indicates the gear ratio. The Twin Wasp has 14 cylinders arranged in two banks of 7 while the Wasp had a single bank of 9 cylinders.
The correct civilian designation for the R-1340-43 is T5H1, T-five-H-one. See attached. In this case the "T" by itself does not mean turbocharged it means "sea level rated." "TS" means turbocharged. It is clear that the XC-35 had added turbochargers but these were not part of the engines themselves but were an experimental installation upstream of the engine air intakes.
gl
gl
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My first post (Reply #16 above) comparing civilian/mil designations refers to the 1830. But I followed it with a post about 1340 (Reply #17), which might have led to the confusion...since the 1830-43s civvie designation indicated a turbo, I was wondering whether the Army's -43 designation in general indicated turbo, and therefore whether 1340-43 (like 1830-43) was turbo. Sorry for the convolutions...
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Some gleanings on turbo issues of that timeframe:
Dr. Sanford A. Moss (1872 – 1946) made the turbocharger practical, advanced the cause of gas turbines, and ended his long career by pressurizing civilian airliners.
While his work on turbochargers would earn him a Collier Trophy, Moss had a deep affection for gear-driven superchargers...the turbocharger gives better performance at high altitude [but] few people wanted to fly above 20,000 ft…[which] was both uncomfortable and dangerous for the aviator. Use of the turbo-supercharger has been limited to a few experimental ships and the most advanced Army planes. And though the Air Corps engineers worked eagerly with Dr. Moss to develop the turbo-supercharger, it never seems to him that the tactical units made adequate use of its possibilities.
In 1937 Moss and his crew adapted the turbocharger to the YB-17, then considered obsolete. Within a year, the bugs had been worked out and the bomber flew faster than most pursuit planes. The turbocharger also made high-altitude strategic bombing possible.
As early as1931, NACA engineers recognized the superiority of the turbocharger at altitude As Oscar W. Schey wrote,
“[F]or altitudes of up to 20,000 feet, when ideal methods of control are employed, there is very little difference in superchargers from the point of view of net engine power, while for critical altitudes of over 20,000 feet an engine develops more power when equipped with an exhaust turbosupercharger than with any other type.
http://enginehistory.org/Piston/InterWarSCdev/InterWarSCdev.shtml
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Some gleanings on turbo issues of that timeframe:
Dr. Sanford A. Moss (1872 – 1946) made the turbocharger practical, advanced the cause of gas turbines, and ended his long career by pressurizing civilian airliners.
While his work on turbochargers would earn him a Collier Trophy, Moss had a deep affection for gear-driven superchargers...the turbocharger gives better performance at high altitude [but] few people wanted to fly above 20,000 ft…[which] was both uncomfortable and dangerous for the aviator. Use of the turbo-supercharger has been limited to a few experimental ships and the most advanced Army planes. And though the Air Corps engineers worked eagerly with Dr. Moss to develop the turbo-supercharger, it never seems to him that the tactical units made adequate use of its possibilities.
In 1937 Moss and his crew adapted the turbocharger to the YB-17, then considered obsolete. Within a year, the bugs had been worked out and the bomber flew faster than most pursuit planes. The turbocharger also made high-altitude strategic bombing possible.
As early as1931, NACA engineers recognized the superiority of the turbocharger at altitude As Oscar W. Schey wrote,
“[F]or altitudes of up to 20,000 feet, when ideal methods of control are employed, there is very little difference in superchargers from the point of view of net engine power, while for critical altitudes of over 20,000 feet an engine develops more power when equipped with an exhaust turbosupercharger than with any other type.
http://enginehistory.org/Piston/InterWarSCdev/InterWarSCdev.shtml
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That may be true but most fighters in WW2 such as the P-51 had geared superchargers. The only fighter with a turbocharger that comes immediately to mind is the P-38.
gl
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Civilian TSC4-G16:9 is military R-1830-43
Thanks very much for this, Gary - I hadn't seen your last edit!
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All,
Whatis the point of this thread? It has been reliably established that NR16020 had the same R1340 S3H1 engines on it when it disappeared as when it was delivered in July 1936. There were no turbochargers.
The XC-35, while an interesting airplane (I've crawled around inside it.) and its engines are not relevant to the subject of this forum.
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What is the point of this thread?
Sheila is trying to defend the credibility of Wayne Green's claim that Bob Wemple installed extra-powerful engines and larger gas tanks in NR16020 (http://tighar.org/smf/index.php/topic,215.msg1983.html#msg1983) so that it could be used to spy on Truk and still arrive in the vicinity of Howland as if it had made a direct flight from Lae.
As part of her defense, she has found out what kind of more powerful engines existed in 1937--they were installed in the XC-35.
It has been reliably established that NR16020 had the same R1340 S3H1 engines on it when it disappeared as when it was delivered in July 1936. There were no turbochargers.
The XC-35, while an interesting airplane (I've crawled around inside it.) and its engines are not relevant to the subject of this forum.
For what it's worth--and it may not be much, I grant you--the interior and exterior pictures of the XC-35 (http://www.nationalmuseum.af.mil/factsheets/factsheet_media.asp?fsID=3296)help to show pretty conclusively that NR16020 was not equipped for pressurized, high-altitude flight. Of course, for those who accept documents from the period in question as evidence already knew that the aircraft had a service ceiling of 10,000 feet. The demonstration that "NR16020 was not an XC-35" may be useful for stamping out some hallucinations about what the government would, could, or should have done in 1937.
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What is the point of this thread?
Sheila is trying to defend the credibility of Wayne Green's claim that Bob Wemple installed extra-powerful engines and larger gas tanks in NR16020 (http://tighar.org/smf/index.php/topic,215.msg1983.html#msg1983) so that it could be used to spy on Truk and still arrive in the vicinity of Howland as if it had made a direct flight from Lae.
As part of her defense, she has found out what kind of more powerful engines existed in 1937--they were installed in the XC-35.
It has been reliably established that NR16020 had the same R1340 S3H1 engines on it when it disappeared as when it was delivered in July 1936. There were no turbochargers.
The XC-35, while an interesting airplane (I've crawled around inside it.) and its engines are not relevant to the subject of this forum.
For what it's worth--and it may not be much, I grant you--the interior and exterior pictures of the XC-35 (http://www.nationalmuseum.af.mil/factsheets/factsheet_media.asp?fsID=3296)help to show pretty conclusively that NR16020 was not equipped for pressurized, high-altitude flight. Of course, for those who accept documents from the period in question as evidence already knew that the aircraft had a service ceiling of 10,000 feet. The demonstration that "NR16020 was not an XC-35" may be useful for stamping out some hallucinations about what the government would, could, or should have done in 1937.
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But the R-1340-43 wasn't more powerful than the S3H1 it was limited to the same 550 hp continuous and it did not even put out as much power as the S3H1 for takeoff since this was also limited to 550 hp while the S3H1 put out 600 hp for takeoff.
See the documents I already uploaded on this.
gl
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Stupid question time fro me AGAIN :) but wouldn't the engines look different if they were changed so making any argument invalid?
p.s. I don't know an aircraft engine from my rear end ;D
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What is the point of this thread?
Sheila is trying to defend the credibility of Wayne Green's claim that Bob Wemple installed extra-powerful engines and larger gas tanks in NR16020 (http://tighar.org/smf/index.php/topic,215.msg1983.html#msg1983) so that it could be used to spy on Truk and still arrive in the vicinity of Howland as if it had made a direct flight from Lae.
As part of her defense, she has found out what kind of more powerful engines existed in 1937--they were installed in the XC-35.
It has been reliably established that NR16020 had the same R1340 S3H1 engines on it when it disappeared as when it was delivered in July 1936. There were no turbochargers.
The XC-35, while an interesting airplane (I've crawled around inside it.) and its engines are not relevant to the subject of this forum.
For what it's worth--and it may not be much, I grant you--the interior and exterior pictures of the XC-35 (http://www.nationalmuseum.af.mil/factsheets/factsheet_media.asp?fsID=3296)help to show pretty conclusively that NR16020 was not equipped for pressurized, high-altitude flight. Of course, for those who accept documents from the period in question as evidence already knew that the aircraft had a service ceiling of 10,000 feet. The demonstration that "NR16020 was not an XC-35" may be useful for stamping out some hallucinations about what the government would, could, or should have done in 1937.
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But the R-1340-43 wasn't more powerful than the S3H1 it was limited to the same 550 hp continuous and it did not even put out as much power as the S3H1 for takeoff since this was also limited to 550 hp while the S3H1 put out 600 hp for takeoff.
See the documents I already uploaded on this.
gl
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And the engine itself had only a geared supercharger, the installation on the XC-35 provided the turbocharger.
See attached Air Force document.
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All,
Whatis the point of this thread? It has been reliably established that NR16020 had the same R1340 S3H1 engines on it when it disappeared as when it was delivered in July 1936. There were no turbochargers.
The XC-35, while an interesting airplane (I've crawled around inside it.) and its engines are not relevant to the subject of this forum.
My thought was that since XC-35 and 10-E were concurrent, and the same designer(s) worked on both, that studying aspects of one may reveal details of the other. It's even possible that notes/data on the XC-35 could directly mention the 10-E. I just feel that after many obviously-relevant sources of info have been exhausted, sometimes digging into possibly-relevant sources can turn up something new. Kind of like not being able to find Bob Wemple until searching for Miss Philadelphia, lol.
While there were significant differences to each project, it was after all the same airframe and both models shared the goal of endurance, and were to fly within weeks of each other. It's possible that notes/discussions of endurance tweaks on one airframe could shed light on whether or not those tweaks may have been tried on the other - if it weren't the same designer, I wouldn't consider it nearly so possible.
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But that said, I'll stop posting on XC-35 (unless I find any reference to 10-E)...
Here's one last nice closeup:
(http://farm5.static.flickr.com/4002/4524576057_59e9cbc271_o.jpg)
http://www.flickr.com/photos/museumandy/4524576057/in/photostream/lightbox/
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But the R-1340-43 wasn't more powerful than the S3H1 it was limited to the same 550 hp continuous and it did not even put out as much power as the S3H1 for takeoff since this was also limited to 550 hp while the S3H1 put out 600 hp for takeoff.
OK. Thanks for the correction.
So Sheila thought she had found a more powerful engine that Wemple might have installed in NR16020 ...
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But that said, I'll stop posting on XC-35 (unless I find any reference to 10-E)...
Thank you.
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But the R-1340-43 wasn't more powerful than the S3H1 it was limited to the same 550 hp continuous and it did not even put out as much power as the S3H1 for takeoff since this was also limited to 550 hp while the S3H1 put out 600 hp for takeoff.
OK. Thanks for the correction.
So Sheila thought she had found a more powerful engine that Wemple might have installed in NR16020 ...
What's the definition of power--speed or fuel efficiency?
Johnson was looking at the turbo aspect (thanks again to Gary for the after-engine turbo info) for a reason; in XC-35's case, it seems to be speed (power?) at altitude; however, his parallel goal was endurance. If he chose 1340-43s in the end (which he did), it's reasonable to ask whether the after-engine turbo aspect contributed to overall endurance.
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But the R-1340-43 wasn't more powerful than the S3H1 it was limited to the same 550 hp continuous and it did not even put out as much power as the S3H1 for takeoff since this was also limited to 550 hp while the S3H1 put out 600 hp for takeoff.
OK. Thanks for the correction.
So Sheila thought she had found a more powerful engine that Wemple might have installed in NR16020 ...
What's the definition of power--speed or fuel efficiency?
Johnson was looking at the turbo aspect (thanks again to Gary for the after-engine turbo info) for a reason; in XC-35's case, it seems to be speed (power?) at altitude; however, his parallel goal was endurance. If he chose 1340-43s in the end (which he did), it's reasonable to ask whether the after-engine turbo aspect contributed to overall endurance.
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The R-1340-43 was "sea level rated." This means that the power output of the engine started dropping off as soon as the plane started climbing. (The power output of engines gets less and less as a plane climbs due to the air getting thinner and thinner as you climb. The purpose of superchargers is to allow the engine to make full power at high altitude.) Since the power output lessened then the plane would reach its ceiling and couldn't climb any higher. The reason to add the turbocharger to the system was to add more "boost" so that the plane could climb to very high altitude. The turbocharger also supplied the compressed air needed to pressurize the cabin which was the true reason for this experimental plane.
gl
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The R-1340-43 was "sea level rated." This means that the power output of the engine started dropping off as soon as the plane started climbing. (The power output of engines gets less and less as a plane climbs due to the air getting thinner and thinner as you climb. The purpose of superchargers is to allow the engine to make full power at high altitude.) Since the power output lessened then the plane would reach its ceiling and couldn't climb any higher. The reason to add the turbocharger to the system was to add more "boost" so that the plane could climb to very high altitude. The turbocharger also supplied the compressed air needed to pressurize the cabin which was the true reason for this experimental plane.
Thanks for this, Gary! I'm also finding refs to turbocharges boosting efficiency (Wiki: "A turbocharger may also be used to increase fuel efficiency without any attempt to increase power...increased temperature from the higher pressure gives a higher Carnot efficiency.")
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Sheila,
I thought you agreed to stop this pointless thread. If you don't, I will.
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"But I don't want to get on the cart ..."
"Oh, don't be such a baby!"
LTM,
Monty Fowler
TIGHAR No. 2189CER
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Shame on you Marty- someone always leads us back to Monty Python!
Jeff Lange #0748C