Thanks Victrola!
Here are some clasic war birds from Aviation Week.
https://aviationweek.com/ad-week/defense-aircraft-we-love?utm_rid=CPEN1000000511129&utm_campaign=24888&utm_medium=email&elq2=132f83af1662456aa04c2f066a790496
With it now not necessary to attempt to link posts in this thread to railroading in some manner, here's a short video that I love of perhaps the most beautiful airplane that was ever designed.
https://www.youtube.com/watch?v=taU6qu5pXBo
While this one was an airliner, any warbird fan will be able to tell you that the Lockheed Constellation also had a long and successful career with the United States Air Force (As well as the US Navy). Both also operated this particular breed, the Lockheed Super Constellation. In particular, it was noteworthy in military service as one of the first AWACS aircraft.
Leo_Amesperhaps the most beautiful airplane that was ever designed.
There is a railroad context, and in fact there is a thread over on the Classic Trains forum of which the 'Excalibur A' is a logical and fairly immediate continuation.
We may recall that one of the great 'innovations' in 1929 was the introduction of T.A.T., which used sleeper trains by night (on PRR in the east and ATSF in the west) and aircraft by day to give improvements in transcontinental speed. This led to introduction of aircraft that would not require 'intermodal transfer' to have sleeper capacity, notably the Douglas DST of 1935 (the widened fuselage of which was instrumental in the success of the DC-3. It is only about half a Depression decade later that Howard Hughes apparently indicated to Lockheed that the 'next generation' of mainliners would want to have 20 sleeper berths, full transcontinental range, and over 300mph cruise speed -- something that Lockheed's contemporary large 4-engine project was considerably 'short' of achieving at the time. Within no more than a couple more years Lockheed produced the project 049 'Excalibur A' with what might be considered enlarged P-38 features, and this rapidly became the Connie airframe we know (incidentally with much better engines in part justified by better expected airline performance). So essentially in no more than eight years from introduction of the DST we had this, perhaps the best of the reciprocating-engine airliners and certainly the most elegant.
I confess to being a bit sad that this came after the heyday of sleeper transport, where the fundamental principle of a train like the 20th Century Limited was realized in air transport: you emplaned decently after the close of business in New York or LA, and after a civilized night's sleep in the equivalent of a ubiquitous Pullman you arrived before the next business day on the opposite coast.
That should have been the wake-up call to the immediate postwar railroads about what was coming; the 'other shoe dropping' was the subsequent introduction of the Comet (which promised to eliminate the overhead of the sleeper service and still give bearable long distance times and equipment utilization that goes with them) -- the engineering issues with that airliner gave railroads a bit of reprieve but the 707/DC-8 put the rest of the nails in the coffin that the enhanced postwar highway/turnpike programs had begun.
Should we have an expanded 'classic aircraft attacking trains' to discuss how airlines took over the function of long-distance trains as a non-automotive travel choice in general?
Also, the Boeing 707 killed the ocean liners "Like a good friend being hit by a truck" as Walter Lord said.
When I was stationed in Norfolk in the 1970s, I would occasionally see the Connie AWACS plane. There were also several R4Ds with curtains in the windows. On the base as exhibits were a Pogo plane, an early attempt at VTOL and the Martin "Truculent Turtle" the first plane to fly around the world non-stop. That one was taken away in about 1977 to be restored, I think. Sitting in one spot on the grass at the air base was a four-engined flying boat, apparently it was a Japanese "Emily." type. It was covered in a preservative coating and was eventually given back to Japan. It wasn't very big as I recall.
The "Truculent Turtle" was a modified P2V Neptune that set a non-stop distance record of slightly over 10,000 miles in the late 1940's. Since Neptunes did not have refueling capabilities, a nonstop round-the-world flight would have been impossible.
Overmod It is only about half a Depression decade later that Howard Hughes apparently indicated to Lockheed that the 'next generation' of mainliners would want to have 20 sleeper berths, full transcontinental range, and over 300mph cruise speed -- something that Lockheed's contemporary large 4-engine project was considerably 'short' of achieving at the time. Within no more than a couple more years Lockheed produced the project 049 'Excalibur A' with what might be considered enlarged P-38 features, and this rapidly became the Connie airframe we know (incidentally with much better engines in part justified by better expected airline performance). So essentially in no more than eight years from introduction of the DST we had this, perhaps the best of the reciprocating-engine airliners and certainly the most elegant.
It is only about half a Depression decade later that Howard Hughes apparently indicated to Lockheed that the 'next generation' of mainliners would want to have 20 sleeper berths, full transcontinental range, and over 300mph cruise speed -- something that Lockheed's contemporary large 4-engine project was considerably 'short' of achieving at the time. Within no more than a couple more years Lockheed produced the project 049 'Excalibur A' with what might be considered enlarged P-38 features, and this rapidly became the Connie airframe we know (incidentally with much better engines in part justified by better expected airline performance). So essentially in no more than eight years from introduction of the DST we had this, perhaps the best of the reciprocating-engine airliners and certainly the most elegant.
I would say the pinnacle of reciprocating engine airliners occured about a decade later with the DC-7C and L-1649. Douglas wanted a bit more payload and range with the DC-7, so decided to extand the wing by adding 5 feet between the root and inboard engines, which dramatically lowered the noise inside the cabin. Lockheed did the same with the Connie's a year later.
Getting back to the origins of the Connie: The 300+ mph cruise speed was made possible by the Wright engines developed for the B-29, though one interesting "what-if" was the turbo-compound Allison V-1710 good for almost 3,000hp at take-off. The sfc of the tubocharged V-1710 wasn't much higher than the Wright turbo-compounds, so a non-stop NY to LA flight would have been easy (this is flying against prevailing winds).
A 180MPH high speed rail system might be good for a 12-14 hour LA - CHI trip, which would make for a nice overnight trip.
Constellations sort of faded away. They ended up being retired before their airframes actually wore out. TWA bought the H model with its extra fuel that ended up probably being the longest time unrefueled ability of any commercial passenger airplane. The Constellations started with the 049 model that was fairly short. Lockheed kept lengthening each model with more powerful engines which had the effect of making each one more stable in yaw. Often suspected that the G and H models did not need the 3 rudders of the other models ?
The air force used Connies for AWACS aircraft for that very long unrefueled endurance that has never been met by jets. However mid air refueling changed the game. The B-36 did have a longer endurance and then also got mid air refueling small jets for takeoff and bombing dashes.
Eastern air lines kept the Connies around a long time. They retired the DC-7s then the DC-6s. The Connies became surplus but became the primary aircraft for EAL's air shuttle. They were paid for and became back up aircraft for the shuttle guarantee and some times as many as 5 an hour would make a trip to BOS or WASH. More than once a single passenger got the last extra section.
Once Electras (~1966) took over 1st sections Connies remained the extra section aircraft. As Electras slowly took over 2nd and the more extra sections Connies slowly were retired. EAL kept several as company material freighters especially for jet engines as Vietnam made Jet engines in very short supply. Once EAL got the B-727QC passenger - freighters the EAL Connies went quietly to bone yards.
blue streak 1 Constellations sort of faded away. They ended up being retired before their airframes actually wore out. TWA bought the H model with its extra fuel that ended up probably being the longest time unrefueled ability of any commercial passenger airplane. The Constellations started with the 049 model that was fairly short. Lockheed kept lengthening each model with more powerful engines which had the effect of making each one more stable in yaw. Often suspected that the G and H models did not need the 3 rudders of the other models ? The air force used Connies for AWACS aircraft for that very long unrefueled endurance that has never been met by jets. However mid air refueling changed the game. The B-36 did have a longer endurance and then also got mid air refueling small jets for takeoff and bombing dashes. Eastern air lines kept the Connies around a long time. They retired the DC-7s then the DC-6s. The Connies became surplus but became the primary aircraft for EAL's air shuttle. They were paid for and became back up aircraft for the shuttle guarantee and some times as many as 5 an hour would make a trip to BOS or WASH. More than once a single passenger got the last extra section. Once Electras (~1966) took over 1st sections Connies remained the extra section aircraft. As Electras slowly took over 2nd and the more extra sections Connies slowly were retired. EAL kept several as company material freighters especially for jet engines as Vietnam made Jet engines in very short supply. Once EAL got the B-727QC passenger - freighters the EAL Connies went quietly to bone yards.
Great post! As a 9 year old kid, I had my first flight of any type on an Eastern (Super)Connie from LaGuardia to Bermuda. Eastern had just taken over Colonial Airlines. Very smooth. And flew on an American DC-6, LaGuardia to Midway to return home. Not as pleasant as the Connie.
Error.
Charlie The DC-6 was not pressurized very much so you had to fly at an low altitude below (?). The Connies were more pressurized. However do not remember their operating altitudes.
There's the old aviators saying, "If it looks good it'll fly good!" and the Connie is a looker all right! Sleek and elegant!
Kind of like this one, which would give a Connie a good run in a beauty contest.
(It'll be a surprise!)
https://www.youtube.com/watch?v=m81wEm1q824
The Mosquito was a great, versatile plane. But the appearance? Not so hot.
blue streak: Thanks for the info on the DC 6. I always thought DC 6 and Connies were pressurized about the same .
Flintlock76There's the old aviators saying, "If it looks good it'll fly good!" and the Connie is a looker all right! Sleek and elegant! Kind of like this one, which would give a Connie a good run in a beauty contest. (It'll be a surprise!) https://www.youtube.com/watch?v=m81wEm1q824
Airframe mechanics require certification - is there certification for Airframe Carpenters?
Never too old to have a happy childhood!
BaltACDAirframe mechanics require certification - is there certification for Airframe Carpenters?
Yes indeed, I believe there is, or there used to be. It comes under the "Airframe" umbrella if you're doing it professionally.
charlie hebdo But the appearance? Not so hot.
Yeah, I suppose if you were a Gestapo goon working in their Copenhagen headquarters on 3/21/1945 a Mosquito was an ugly sight indeed!
blue streak 1 Charlie The DC-6 was not pressurized very much so you had to fly at an low altitude below (?). The Connies were more pressurized. However do not remember their operating altitudes.
Wikipedia entry says service ceiling for the DC-6B was 25,000', which may be as much engine limits as pressurization. ISTR that the Coniies had a similar ceiling. Jets had higher ceilings to keep fuel consumption under control.
The DC-6's tended to outlast the Connie's and DC-7's as the Double Wasp used on the DC-6 was a more reliable engine than the Wright Cyclone used on the Connie's and DC-7's. My last flight on a DC-6 was July 1968 on an United flight from Reno to LAX, UAL retired their DC-6's a bit over a year later.
N.B. One tutorial on simulating flying propliners mentioned that a DC-6 had to burn off quite a bit of fuel to reach 25,000'. Part of that was due to ATC rules requiring that climbs be done at 500fpm.
Flintlock76 BaltACD Airframe mechanics require certification - is there certification for Airframe Carpenters? Yes indeed, I believe there is, or there used to be. It comes under the "Airframe" umbrella if you're doing it professionally.
BaltACD Airframe mechanics require certification - is there certification for Airframe Carpenters?
Balt referred to the wood laminate construction.
Erik_MagGetting back to the origins of the Connie: The 300+ mph cruise speed was made possible by the Wright engines developed for the B-29, though one interesting "what-if" was the turbo-compound Allison V-1710 good for almost 3,000hp at take-off. The sfc of the tubocharged V-1710 wasn't much higher than the Wright turbo-compounds, so a non-stop NY to LA flight would have been easy
The 'best' of all the powerplants, though, wasn't a piston engine, or an American turbine; it was the engines used in the Tu-95 (for which there was actually a somewhat Connie-ish "airliner" counterpart (no one I know was particularly deceived) which had a transmission in the final drive to slow prop rpm at altitude for sustained cruise ... which was astounding for a high-subsonic aircraft. This type of engine woud hae worked nicely in the turboprop variant of what became the B-52 ... and the Stratoliner-like wide-cabin multiple-deck airliner variants of such an aircraft. It is not difficult for me to imagine an aircraft with the comfortable sleeper accommodation of a Pullman train, with lounges, galleys, in fact the option of Princess-like accommodations, that could fly a coast-to-coast route comfortably overnight. One might think of the current generation of luxury widebody aircraft with geared turbofans as a fancier version of the same thing...
charlie hebdoBalt referred to the wood laminate construction.
I know.
To my knowledge, wood construction aspects are covered in the training for, and the FAA examination for, aircraft maintenance. I think there is an option in current PSI testing for a certificate just for 'airframe' (AMA) if you don't want what I used to call the A&P certificate (I think now called 'aircraft maintenance - general')
Backshop and others will probably be laughing at us over this because they know what is involved in practical maintenance and it goes far beyond what the FAA's program is testing for. The right criterion for specialty wood construction likely goes far beyond what a formal test comprises, and when you get into formed composites of the type that becomes possible even with resin glulam and selective bending I suspect you're outside what a 'professional airframe mechanic' in general aviation would have any need to know. It is then the professional responsibility of an AMA intending to specialize in such construction to learn the field (both in knowledge and practical experience) and for any aircraft owner or pilot intending to fly an aircraft of such construction to learn how the tricks are done, what to look for in preflight examinations, how to assess if a given 'professional' understands The Knowledge or not. In my opinion it's the same as in medicine: there is no formal 'government certification' in how to run a 19-micrometer laser or program a da Vinci robot for in situ spinal kyphosis, but you'll want to satisfy yourself as a patient that a doctor proposing to use such technology is conversant in its proper use as well as the more common-sense and appropriate methods in modern surgical medicine.
One of the things FAA does do, though, is regulate the technologies actually used for certified production aircraft. If you're using specialty construction or techniques, expect to be kept in 'experimental' status until the longevity of your methods is established -- or expect ADs if any shortcoming or problem is detected or determined likely. (Just as for railroads these can come in the form of NPRMs, notices of proposed rulemaking, with whatever 'final rule' changes and details are adopted going in the Federal Register and being incorporated in the relevant section(s) of the CFR.)
OvermodTo my knowledge, wood construction aspects are covered in the training for, and the FAA examination for, aircraft maintenance. I think there is an option in current PSI testing for a certificate just for 'airframe' (AMA) if you don't want what I used to call the A&P certificate (I think now called 'aircraft maintenance - general') Backshop and others will probably be laughing at us over this because they know what is involved in practical maintenance and it goes far beyond what the FAA's program is testing for. The right criterion for specialty wood construction likely goes far beyond what a formal test comprises, and when you get into formed composites of the type that becomes possible even with resin glulam and selective bending I suspect you're outside what a 'professional airframe mechanic' in general aviation would have any need to know. It is then the professional responsibility of an AMA intending to specialize in such construction to learn the field (both in knowledge and practical experience) and for any aircraft owner or pilot intending to fly an aircraft of such construction to learn how the tricks are done, what to look for in preflight examinations, how to assess if a given 'professional' understands The Knowledge or not. In my opinion it's the same as in medicine: there is no formal 'government certification' in how to run a 19-micrometer laser or program a da Vinci robot for in situ spinal kyphosis, but you'll want to satisfy yourself as a patient that a doctor proposing to use such technology is conversant in its proper use as well as the more common-sense and appropriate methods in modern surgical medicine. One of the things FAA does do, though, is regulate the technologies actually used for certified production aircraft. If you're using specialty construction or techniques, expect to be kept in 'experimental' status until the longevity of your methods is established -- or expect ADs if any shortcoming or problem is detected or determined likely. (Just as for railroads these can come in the form of NPRMs, notices of proposed rulemaking, with whatever 'final rule' changes and details are adopted going in the Federal Register and being incorporated in the relevant section(s) of the CFR.)
My son is a master at metal fabrication - however, when it comes to wood, he finds it hard to find a place to tack weld two pieces together. Different construction materials require different skills.
He is not involved in any form of aircraft maintenance or repair.
Overmod Erik_Mag Getting back to the origins of the Connie: The 300+ mph cruise speed was made possible by the Wright engines developed for the B-29, though one interesting "what-if" was the turbo-compound Allison V-1710 good for almost 3,000hp at take-off. The sfc of the tubocharged V-1710 wasn't much higher than the Wright turbo-compounds, so a non-stop NY to LA flight would have been easy Did Allison develop a turbocompound V-1710? It doesn't seem to me there is any good place to put the required transmission (at either end of a V-16 driving a propshaft) while maintaining the required exhaust-header balance to use, say, the arrangement in a Wright turbocompound (which is easier and more direct on a radial). I suspect you mean 'turbosupercharged' and not 'turbocompounded' which is a very different thing. I do confess it would be interesting to see the effect of crankshaft-coupled exhaust compounding on the sfc of an (otherwise correctly pressure-charged at altitude) V-1710...
Erik_Mag Getting back to the origins of the Connie: The 300+ mph cruise speed was made possible by the Wright engines developed for the B-29, though one interesting "what-if" was the turbo-compound Allison V-1710 good for almost 3,000hp at take-off. The sfc of the tubocharged V-1710 wasn't much higher than the Wright turbo-compounds, so a non-stop NY to LA flight would have been easy
Did Allison develop a turbocompound V-1710? It doesn't seem to me there is any good place to put the required transmission (at either end of a V-16 driving a propshaft) while maintaining the required exhaust-header balance to use, say, the arrangement in a Wright turbocompound (which is easier and more direct on a radial). I suspect you mean 'turbosupercharged' and not 'turbocompounded' which is a very different thing. I do confess it would be interesting to see the effect of crankshaft-coupled exhaust compounding on the sfc of an (otherwise correctly pressure-charged at altitude) V-1710...
Allison started looking into turbo-compounding ca 1940 and built a prototype in 1945. Coupling between the exhaust turbine and crankshaft was at the rear of the engine, with a fluid clutch and reduction gear. Exhaust plumbing would have been similar to the P-38. Unlike the Wright TC's, the turbine was connected by a shaft to the impeller of the first compressor stage. SFC at ~1400hp and 26,000' was 0.365 lb/hp-hr, which I believe was better than the Wright TC engines (0.38 - 0.39lb/hp-hr??)
On a somehwat related note, had the P-51 been equpped with a turbocharged V-1710, it would have had about 30% more range than the Merlin powered P-51's. Top speed may have been slightly less as both the Allison powered and Merlin powered P-51's used exhaust energy to provide thrust.
The above data is from the book "Vees for Victory", which covered the history of Allison up to ca 1948. I got my copy late January from Karen's Books, been wondering about the story behind the V-1710 versus the Merlin for the Mustang - first read about that ca 1964 in the American Heritage book about the Air War over Germany.
Erik_MagUnlike the Wright TC's, the turbine was connected by a shaft to the impeller of the first compressor stage.
Can you be a bit more specific (or link to drawing(s) or specific sources?
A turbocompound is a mechanical device, as you noted one that provides additional torque directly to the engine mainshaft. Why would the turbine providing this be coupled to an 'impeller' of a 'compressor' unless the torque were being transferred hydraulically rather than through planetaries and clutches -- something that to me makes little engineering sense in terms of what turbocompounding on aircraft is supposed to provide? My current understanding of the arrangement is that the turbine shaft ran through the first-stage supercharger impeller (i.e. through a hollow shaft) to reach physical connection with the crankshaft, as in this quote from an online reference:
The shaft from the turbine ran through the centre of the first stage supercharger impeller, back to the engine and put its power directly into the crankshaft. The turbine could not be connected to the supercharger impeller because the supercharger was driven by a variable speed transmission, which did not run at a fixed speed ratio with respect to either the crankshaft or the turbine.
The fuel-economy advantage of turbosupercharging over mechanical supercharging has been well-established almost since the first use of exhaust turbines for the purpose, and as you know is readily established from practical equivalents of the Carnot cycle for internal combustion. To my knowledge the use of pressure charging in that era was more to maintain 'sea-level' engine performance at higher altitude, much as GM actually did with the turbo on the 6.5TD in stock configuration, with performance retention rather than 'power adding' being the criterion (this certainly seems to be the rationale behind two-speed supercharging of the Merlin as designed). Just as the ihp of steam engines increases with altitude, so does the advantage of exhaust-gas turbine compression of intake air relative to decreasing required back pressure across a turbine compared to mechanical shaft drive providing an equivalent mass flow of combustion air.
I won't pretend to second-guess engineers who, calculating a given amount of recoverable heat in engine exhaust, prioritized augmented physical torque as a 'first stage' followed by turbosupercharging, as opposed to using just the amount of gas energy to 'make up' combustion reuirements moment-to-moment and then recovered 'the rest' as torque (as in some of the roadgoing exhaust-turbine approaches). But I would like to see if the turbocompounded V-1710 in particular used staged or sequential expansion in one order or the other, and how much available energy was recaptured in each 'part' in different operation regimens.
I suppose I'd settle for a readable copy of the 1949 SAE report on 'compound powerplants' (my reference says #490226) which covers both the detail design and specific reasons why it was not pursued (likely more bang for the buck in straight turboprop combustion turbines). I have some access to JSTOR but cannot find this particular paper digitized and accessible through them.
(Incidentally, when I first looked at the specs for the turbocompound engines in late airliners, the contribution from the exhaust turbine unit was supposed to be around 300shp. The modern references show a much larger amount -- approaching 800shp but with substantial flown-weight increase per engine. Which is correct?)
I was often told that the turbo compounding of the DC-7s caused some problems with overheating. They said that the -7s never could cool properly and often would swallow certain charger parts. Told that was the reason EAL retired their -7s before their -6s. Delta also did the same thing.
On the Connies the R4360s did not have that problem . When EAL started using the Connies on the shuttle the altitudes they usually operated were at no more than 13,000 or 14,000 feet. EAL actually operated them at lower BMEPs than their ratings for take offs, climb, and cruise except for emergencies. Also they used ADI for take offs. That also saved the engines. -7s only stayed on the shuttles for a couple months.
Those Connie power plants were very reliable with few failures. Never had a recip failure. EAL maintained their own recip engine overhauls for Connie R4360s and the R2800s for Martin 404s and Convair 440s. Told EAL had the highest recip MTBF of all the airlines.
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I am beginning to really dislike how this site, and its dancing ads, and its delayed loading and page buffering, works with Chrome.
I believe this is the approach proposed for 'turbocompounding' on the R-4360:
https://external-preview.redd.it/eAbL99dur5rCnxZrq_rW2IhKtGonaZCyP7XHwHh2XBg.jpg?width=960&crop=smart&auto=webp&s=41d75aa37a2a4faaebaad4add008fa1c21112e5d
This is the kind of pure-gold information that would be hard to find anywhere else ... and will be increasingly hard as the edge of history sweeps across those who remember the era, and when the technology was cutting-edge...
I thought there were some Connies that got compounded 3350s, including the L1049C and 1649 Starliner, after 1953.
blue streak 1Told EAL had the highest recip MTBF of all the airlines.
Moon man Borman was way after that. Maybe after 1976? The last recips were the Convair 440s that were gone by ~1971. Near the last year of CV-440s EAL had to expand their jet engine overhaul facility displacing the recip overhaul to a contractor. That really change our attitude when flying those contract engines. Never had 2 contractor engines on the CV-440s always checked if engine was a contractor engine to be nurse maided. As for the Connie freighter's engines unknown. With very little use probably had enough Connie engines until 727QCs retired the Connies.
EDIT AS for the Cs, 3350s and 1649s have no knowledge.
Yes the operating practices that were not in the airplane flight manual but were just bulletins often gets lost in the history books.
OvermodI am beginning to really dislike how this site, and its dancing ads, and its delayed loading and page buffering, works with Chrome.
Try uBlock a extension for Chrome.
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