Hi Wayne
>> Looks like we're drifing off 1361 ..<<
not if one will register his historical aircraft under # 1361 .. no ?
Uhm , 'xcuse me .. ? No , definitely not , my Cutie-Comet would be # ... ( crzhk-brzz )
ups , sorry , something happened .. can'xx pst brx -thing
brzzz zwivvex tzing-pshshsh-plix
the electronix gomix ...
= X ..
Looks like we're drifing off 1361, but ah, so what? The dis-interested don't have to hang around if they don't want to.
Contact!
Juniathasuiting turbines could *not* simply be chosen from catalogues of large radius intake high by-pass turbofan types used today because of the unique hidden installation of the turbines within wing roots ; wing roots and wing box probably would need to be visibly changed and substantially strengthened – which would have to be done sensitively for to transcribe original lean elegance as smoothly as possible .
Yes, that is EXACTLY what I meant.
And yes, it would spoil the beautiful lines of the aircraft to have externally-podded engines of any kind.
Firelock 76 wrote Sun, Aug 25 2013 3:16 PM
>> Captain Eddie Rickenbacker, the American ace from World War One and later the head of Eastern Air Lines had a story about the Comet in his autobiography. ... As Capt. Eddie told the story, when he left the cockpit he looked down the length of the fuselage and saw the sides flexing in and out. When the aircraft landed he brought this to the attention of the DeHavilland representatives who said they were well aware of it and that it was nothing to worry about. Rickenbacker said it was something they SHOULD worry about because sooner or later the metal was going to fatigue and crack. Needless to say Eastern didn't buy any Comets. <<
Yeah – I know that story , *gee* , ‘nothing to worry about’ – at least not for ~ descendants of Sir Francis Drake ...
Overmod wrote Sun, Aug 25 2013 4:04 PM:
>> In fact the only real changes that needed to be made, at the time, would be the elimination of stress raisers in the skin <<
Exactly *that* *had* been examined and sorted out for production of the last series , plus the fuselage had been strengthened , too , I believe .
>> Long-term development of the Comet would have been, in my opinion, restricted by the limits on engine size and capacity; <<
Really , I don’t care . Honestly I would feel it was large enough for me as a flying living room - *gee* . What I like is the shape of fuselage as well as empennage as well as the wings although it’s clearly from the beginning of the age of commercial jet clippers – it’s just cutie-cute
What *would* be much more of a point however : suiting turbines could *not* simply be chosen from catalogues of large radius intake high by-pass turbofan types used today because of the unique hidden installation of the turbines within wing roots ; wing roots and wing box probably would need to be visibly changed and substantially strengthened – which would have to be done sensitively for to transcribe original lean elegance as smoothly as possible .
Regards
Juniatha
Juniatha[with] today's materials and suiting detail re-design , with the large wing surface she offered she could be made into one great aircraft .
No question. In fact the only real changes that needed to be made, at the time, would be the elimination of stress raisers in the skin (round windows, or curved corners a la Boeing) and perhaps a better aluminum alloy or post-forming treatment.
Long-term development of the Comet would have been, in my opinion, restricted by the limits on engine size and capacity; specifically, no high-bypass turbofan could be accommodated without substantial redesign. The 707 and the VC-10, both beautiful aircraft too, didn't have this difficulty to the same extent.
Now, something I'd like to see is a turboprop Brabazon, perhaps with the counterrotating props and HP output of Brandner's NK-12... all the beauty, and four times the range...
Hi Juniatha!
Yes, you're correct DeHavilland built Comets for the RAF, except the airplane was called the "Nimrod" and was a sub-hunting aircraft. In this role it was very successful, the last ones flew into the early 2000's.
Captain Eddie Rickenbacker, the American ace from World War One and later the head of Eastern Air Lines had a story about the Comet in his autobiography. When the Comet was introduced Eastern was very interested, so DeHavilland arrainged a demonstration for Rickenbacker. He even took the controls and flew it for a while, and was very impressed with the performance.
As Capt. Eddie told the story, when he left the cockpit he looked down the length of the fuselage and saw the sides flexing in and out. When the aircraft landed he brought this to the attention of the DeHavilland representatives who said they were well aware of it and that it was nothing to worry about. Rickenbacker said it was something they SHOULD worry about because sooner or later the metal was going to fatigue and crack. Needless to say Eastern didn't buy any Comets.
Eastern DID have nasty problems with the prop-jet Lockheed "Electra" several years later, so did several other US airlines, but that's another story.
Wayne
>> A DeHavilland Comet? Hmm, let's see now, would that be the Comet from the '50s that, uh, had its share of problems? <<
Correct . However it's not that I'm seeking a spectacular way for commiting suicide , they later sorted out the hulk fatigue problem ( yet by then no airline dared to order , I think they only built another series for the RAF )
As stated on your linked site : by today's materials and suiting detail re-design , with the large wing surface she offered she could be made into one great aircraft .
locoi1sa wrote the following post at Sat, Aug 24 2013 6:33 PM:
>> J. Comparing the K5s with the K4s is like comparing apples and oranges. <<
Who's meant by >> J. << ? Jenny , John , Jeremy , Junipher , Janis , Jack , Jill , Jordan , Judith ..?
Since my name also starts with same letter :
in case this should be addressed to me
Sorry , but you completely missed the point , actually missed all of what I was conveying .
However , I think it probably wasn't meant as an answer to my post , so just ignore this text .
" don't think twice - it's alright " ( Bob Dylan )
= J =
J.
Comparing the K5s with the K4s is like comparing apples and oranges. The poppet valve K5s #5699 had slightly more TE but less FoA than the Walschaert valve #5698. The K4 already had the maximum weight on drivers allowed where both K5s had the same or slightly more weight on drivers. The Kiesel designed boiler of the K5s was prone to water carryover and not as efficient as it should have been if the clearances were increased had a taller steam dome were installed. Both K5s were an experiment of sorts to eliminate double heading on lines where a larger locomotive could not go. Why not build a 4-6-4? Two reasons. Weight on drivers and believe it or not drafting room time. Then ask why not use the M1? There were places the M1 was not used due to clearances and supporting facilities. Was the K5s a success? Yes and no. Frequent failures of the poppet valve on the Baldwin built #5699 and the #5698 Juniata built K5s was high maintenance and did not eliminate double heading heavy trains. Both were plagued by smoke problems, cinder build up in the smokebox and superheater tubes and water carryover. They both lived long lives though. I feel that if they were moved to the Lines west and increased the height of the steam dome and added some weight on drivers they would have been a much different locomotive.
Charlie Meyer did a fantastic article for the Winter 1995 Keystone. Designed and built by true railroad men as a hand fired beast. The PRR was a no frilled railroad.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
rfpjohn I'm guessing these modifications were done post-war. Would there not have been a corresponding increase in tractive effort with the increase in boiler pressure?
I'm guessing these modifications were done post-war. Would there not have been a corresponding increase in tractive effort with the increase in boiler pressure?
There was a minimal increase in TE when Baldwin got in the picture in 1927, the "5400 series" had all things equal except for a slight increase in heating surface size, the installation of E type superheaters and a weight increase of about 4500 pounds. A PRR comparison of variations done to the K4, including the K4sa, the poppet valve and gear types indicated no measurable difference, although the adheason factor was slightly affected. A "standard K4" was 5.02, the K4sa was 4.72.
rfpjohnAlso, I've always assumed the K4s was built with type "A" superheating. Somewhere along the way, I seem to recall seeing a photo of a K4s equipped with type "E" superheaters. Just wondering if this was a modification in conjunction with upgrading to K4sa.
According to "THE MANY FACES OF THE PENNSY K-4", page 92 # 5400 - 5499 built by Baldwin and Juniata in 1927 - 1928 had type E superheaters. "The superheating surface was reduced from 1153.9 to 962 square feet ..."
Best wishes, Helmut
A Word on Slipping and Boiler Pressure
It wasn’t really increased boiler pressure that provoked “ slipping “ but increased cylinder tractive effort while wheel diameter and adhesion mass remained the same or was but slightly increased .
Cylinder tractive effort could be increased by *any* of the determining factors mean cylinder steam pressure , diameter and stroke – this way t.e. *could* be increased even by no more but amending a throttling point in steam flow upstream from steam chest to steam dome . Since to increase piston stroke would directly affect wheels design , in practice this was limited to cases when building another batch of engines to a second version of a given design . Scope for increasing pressure in existing boiler was rather small , so it was modification of cylinder diameter that was more commonly being used to adapt cylinder t.e. to demands – i.e. boring out or lining cylinders , and that but within strict limits defined by structural strengths of cylinder block and drive .
In a completely revamped design of a given class , such as the PRR K5 was to the K4 class , all three factors *could* and in this very case *had* been increased .
The resulting engine really was not likely ‘more slippery’ than the original if comparison was being properly based , namely : per same amount of t.e. exerted – or , more precisely , for same factor of adhesion applied !
What made the K5 appear more “slippery” in actual traffic was their reaching actual limit of rail adhesion much easier than the K4 , at but a certain percentage of b.p. in steam chest rather than allowing maximum pressure to steam chest . Since in the K5 the factors of steam pressure , cylinder diameter and stroke *all* got quite substantially increased , the engine’s cylinder t.e. would have been much higher at full 1/1 throttle than in a K4 .
It must be understood , with both engine classes having much been designed to the same technology concerning frames structure , wheels , axles , rods and cylinders there was no reason to expect the K5 to put a substantially larger t.e. down on tracks with but little more adhesion mass on driven wheels . Sure enough however , she was able to put down t.e. according to *the same* factor of adhesion t.e. per unit of adhesion mass as the K4 – and thus , correctly handled , was *not* by any means more prone to slip wheels at just that .
Only – and that bespeaks severe lack of communication between design and running departments – if handled like a K4 – incorrectly that is , starting with throttle wide open or 1/1 – the K5 got overstressed and had to slip on any but the most dry and clean rails .
Still , it had been correct to increase cylinder volume and with it t.e. in the K5 since the larger boiler capacity was expected to realize a larger cylinder power output . In an engine with ample cylinder volume in relation to b.p. and adhesion mass , when linking up , the concordant drop of mean cylinder pressure could at least partly be compensated by widening on the throttle and increasing steam chest pressure . Thus , ironically , with *ample* cylinder volume engine performance was improved only *above* starting / low speed , in speed ranges where full boiler output was being reached by running at clearly shorter than ‘drop down’ cut-off , say , like 50 % during acceleration around medium speed range , shortening to 40 % and less as speed rose , all that while applying full boiler output continuously with rpm increasing . In the K5 this was somewhat optimistically backed up by a hefty 25 % plus in b.p. . Yet , properly handled the engine should have been able substantially to outperform a K4 in acceleration . Then again , what must have put a premature upper speed down trend to this promising since rising development of cylinder power graph over speeds was dramatically inadequate steam distribution and steam port cross sections , lack of inner streamlining of cylinders , not to mention influence of superheating , cylinder insulation and effective low back pressure exhaust . So in upper to top speed range all the larger cylinder volume will have been of little benefit to the K5 , effectively confining the heavy Pacific to work ranges of a formidable ‘Pullman train puller’ while becoming increasingly phlegmatic when pressed to reach speeds above some 65 .. 75 mph .
A new built K5s due to much superior grades of steel could have some 300 psi b.p. with the historic size of boiler and would preferably have concordantly reduced volume in cylinders of much improved tribology , long lap Walschaerts with large piston valves .. and many more improved features .
K4sPRR:
Also, I've always assumed the K4s was built with type "A" superheating. Somewhere along the way, I seem to recall seeing a photo of a K4s equipped with type "E" superheaters. Just wondering if this was a modification in conjunction with upgrading to K4sa.
Thanks for your info.
rfpjohnOne variation, applied to five engines, I think, was classed K4sa. I seem to recall reading these engines sported a boiler pressure increase to 220lbs. Can't find where I got that from, but I know they had front end throttles and 15" piston valves
You are correct, five were converted to the K4sa classification, numbers 612, 1985, 5405, 5481 and 5484. In addition to the front end throttles and the 15" piston valve, disk drivers and circulators were also added to them. The circulator increased the heating area by 42 sq. ft. The K4s had a boiler pressure of 205, the K4sa did see a slight increase in pressure so your 220lb is in the ballpark. (Can't locate my copies of test plant results to verify that.)
Juniatha:
I couldn't agree more with ending the great tube tussle.
As for rebuilding a K5s, that's an interesting proposition. The two examples on the Pennsy were kind of oddball orphans. They were noted for having too low a factor of adhesion, slippery as goose exhaust. What strikes me as strange, is where they spent a good deal of their career, lugging heavy trains over the steep and twisting Northern Central line, between Baltimore and Harrisburg!
The Pennsy did tinker with the K4s. Poppet valves (three different configurations) roller bearings, etc. One variation, applied to five engines, I think, was classed K4sa. I seem to recall reading these engines sported a boiler pressure increase to 220lbs. Can't find where I got that from, but I know they had front end throttles and 15" piston valves. Maybe some Pennsy-phile can enlighten us.
Anyway, I do appreciate your expertise in the steam locomotive field. Carry on, please!
rfpjon
# *50*
.. and since we are at it :
if new yet historic -
why not 're-build' a K5 ?
.. and since the two K5 locomotives , with two different valve gear and continuing variations during their active life , may be considered having been would-be prototypes with a certain experimental touch about them - the Pennsy tried to challenge Hudsons by 'superizing' their iconic Pacific type - a certain 'superizing' again of the K5 'Super Pacific Type' by some improvements to combustion efficiency , steam production and steam circuit could better fit a new-built K5s than a new one of a fleet of K4s ( with the new K5 's' meaning superized i.e. improved rather than superheating )
Hi RFPJOHN
Ok , let's just leave it at that , I see you pointed out not all designs were fully to considerations we can trace back today . Some ideas such as raising the front end of tubes slightly might help firing up a locomotive arguably were less than fully rational .
Reboilering by the railroad running the engines commercially did happen to some extend for example on German railways . Same way as there , the Pennsy might not have kept original shapes of boilers but may have opted for centralized conical type or in other words may have put boilers on their locos that were to the more modern types describes in the LC41 . That would have put K4s fans into some conflict about an original or a reboilered type ... as is actually the case with German fans of certain classes that existed in both original and reboilered form .
Yes, I am aware that the E6s was a fully outmoded design in 1941. The Cyclopedia offers illustrations of several locomotives from previous decades. I guess the E6s was considered a successful design, 100% still in service in 1941. I'm not sure of their motivation. I was merely attempting to point out the tube arrangement as portrayed by the drawing mentioned in my previous post. The dimensions I sited were derived from the figures on the drawing, showing distance, in inches from the boiler centerline. They also show a different center line for the smokebox! I learn something every day.
As for constructing a new welded boiler for the 1361, I'm all for it. I'm certain that if steam had continued on the PRR, reboilering with newer construction methods would have been a natural evolution. If doing such would extend the operating life and possibly enhance the performance of a living K4s, by all means, let it be done!
rfpjohn Wed, Aug 21 2013 3:11 AM:
>> I hate to be a pill about the wagon top boiler thing, <<
We will agree on that .
I invite you to re-read my posting , paragraph on tapered boiler and tubes arrangement .
The E6 boiler of 1910 was *also* fully out-moded in 1941 and since it was a very short boiler its shape was not applicable to a large 1940s type of steam locomotive .
The M1 boiler had a special arrangement in its firebox to combustion chamber connection and a complementing arrangement in the front tubes plate . If you insist on the book , take a look at the drawing and you'll find what I wrote about .
Btw - if you look real closely at some drawings you'll find bends and dents in some lines - these are drawing errors , these drawings were made in the 'ruler and pencil hand drawing era' - the real thing was supposed to be straight of course - no need to 'manufacture' a dent in a boiler shell or a bent in a frame bar there in case of making a replica , *ggg* .
And to repeat once more :
I was *not* ( not !) proposing *any other form* of boiler for building a replica boiler for # 1361 than the original - on the contrary , all that we are discussing here is : I pointed out *any* shape *can* be manufactured by welding ( and so that includes the original shape , too ) The original boiler shape can be met by welding process , if the sheets actually are butt-joined or overlapping will *not* ( not !) show when the boiler cladding is on . There will be *no* difference in outer looks , not by an inch , if a new boiler should be built to original shape and dimensions .
And to be extra-sure : yes , it can be made Wagon Top , too .
I hate to be a pill about the wagon top boiler thing, but I went back to the 1941 Locomotive Cyclopedia. Lo and behold, on page 268, figure 3.22 shows an extended wagon top boiler of a PRR E6s atlantic. The position of the top flue and the bottom tube are shown. Strangely enough, the top flue is shown to actually ascend 1/4" from the front sheet of the firebox to the front flue sheet. The position of the lowest tube is shown to descend 1/4" form the firebox to the front flue sheet. Why this spread arrangement? Maybe to aid in boiler water circulation? The Pennsy was pretty cutting edge in 1910 when the E6s was designed, but I would be amazed to find that they were able to map boiler water circulation well enough to determine that such a minute diversion from parallel would make a difference.
As to the arrangement of the M1 flues, the cross section drawings showing some tube placement is a bit over my head, so I couldn't make any sense of them. The side view is of no help, either.
You mention that the wagon top boiler was long outmoded by 1941. This is true. However, we are talking about the 1361 and she carried that outmoded extended wagon top boiler with a Belpaire firebox her entire career.
So, anyway, I got that out of my system. Thank you for making me think a little. It's not something I normally do!
Hi Juniatha! A DeHavilland Comet? Hmm, let's see now, would that be the Comet from the '50s that, uh, had its share of problems? Or the Comet from the '30s that was a spectacular twin-engine race plane?
Me, I want a Fokker Dr1 Triplane! On the other hand, the Nieuport 28 that retired Air Force colonel was flying looked pretty good too! And how'd you like it when that American fighter pilot from 1918 turned and looked straight into the camera? Pretty amazing when you make eye contact with a man who lived a century ago. Thank God for movie film!
Sorry to drift everyone, but if you're wondering what we're talking about check my previous post and that link I suggested.
OK, back to steam now.
I clicked on the "Don't cha dare to !" and - uh - ok , well , looks very practical .. veery practical indeed .
Uhm - can I have a DeHavilland Comet 4 , a 4-4 that is ?
Oops , sorry , about steam .. uhm - yep ..
well , I'd like a ..
and a ..
and ...
dumdilidum ..
Repligards
You know, you're absolutely corrrect in that if you're going to build a steam locomotive replica you might as well put all the technical improvements into it you possibly can, it'll be better in the long run if you do.
In that vein, there's a website I'm sure you'll find interesting, and I'm sure everyone else will find interesting as well. It's www.kcdawnpatrol.org, the site of a flying club that owns World War One replica aircraft. They've taken the approach of building the aircraft with all the modern improvements possible both for performance and longevity. There's a video on the site labeled "Do Not Click On This Link", however they're just kidding, they DO want you to click on it. I've watched it several times, it's amazing!
Seems like those who are anxious about the historical value of the engine would - deep in their hearts - prefer to have it sit safely ( wherever that might be ) in a closed and dry inside of a room , hall or museum .
To run one , we should then rather build a replica .. and if we build a replica we might as well include some technical improvements .. and if we do that we might as well include some more improvements including ... well , I don't post examples here .
So , in the end I come back on my position suggesting to build *new* classic steam if building an engine fully new , rather than building a replica like the Brits have done with the Peppercorn Pacific : That one is new - yet *isn'*t new , no new look , no new engine , no new performance - just the same all over again . It's old history re-visited . DaCapo .
The k4's ran faster than 80 most of their service days.
On heavy trains, two locomotives would be used but speed was their thing. As one who has watched the K4's and T1's in action, I can say they were speed demons.
CZ
rfpjohn Wed, Aug 14 2013 5:11 PM
>> As for pointing the tubes in a wagon top boiler downwards towards the front tube sheet, I don't think that was common practice. When I hauled out the trusty old 1941 Locomotive Cyclopedia, none of the drawings indicated a slope to the tubes. <<
No wonder : by 1941 the Wagon Top boiler was fully outmoded for just that characteristic I had referred too , namely the smokebox tube sheet sits *inevitably* lower than the firebox tube sheet . Now , combine this type of boiler with a firebox having a combustion chamber , then *inevitably* you have a ring around the tubes field of firebox tubes plate according to free length of combustion chamber staybolts . Can you place tubes to that ring shape cross section that is *not* covered by the firebox tubes plate ? Of course not . Then what does that mean ? It means you must leave that space free of tubes along the adjacent boiler . Now if the front end of your conical boiler shell in that section , placed with its lower side horizontal and the upper side sloping down towards the front - how high is your front tube sheet pitched in relation to the back end cross section of this conical boiler shell ? Higher - as high - lower ? It sits *lower* What does that mean for arranging tubes ? You *may* position them horizontally if you allow for loosing that ring shape cross section originating from the staybolted space around the combustion chamber all the way through the boiler barrel . If your front end boiler cross section is significantly smaller in radius than the back end , then you will get a pretty cramped tubes arrangement in the upper area where the smaller radius is being felt in combination with the lower pitched center of the front end cross section .
That is why very few Wagon Top shaped boilers were used in combination with a combustion chamber ; without a combustion chamber you don't have that problem , I sincerely hope it is self-explaining why . That again is why this shape of boiler was on the way out as soon as the combustion chamber was on the way in .
The much better proposition then was to keep all boiler length on the same horizontal center line and have the conical section(s) symmetrically arranged around it , in other words the boiler would taper in the same amount all around from top to lower side ( and of course both sides left and right , too )
In the Loco Cyclopaedia 41 the vast majority of boilers thus is of that latter shape , not Wagon Top . Of the older down-pointed types there are no tubes arrangements shown , so how do you know - do you know all of these boilers' tubes arrangements ? I have seen only one true Wagon Top boiler with combustion chamber and that was the one of the PRR M1 - and that one didn't use the lower space around the front end tube plate because that plate had been equipped with the counter-part of an expansion welt between firebox and combustion chamber . However , I must note one thing here : I'm not intending to write lengthy explanations , justifications and proves over several postings on each posting where I dared to remark anything that - with enough determination *may* be misunderstood by someone wanting to do so .
Aside from a coat of paint I believe the tender is done. The frame,drivers and other parts are at Altoona, The old smoke box , back head sheet and some other parts are outside with 1361 chalked on them. The side sheets were replaced at Steamtown, As I understand it , further testing found the crown sheet was too thin to meet the new regs. I think the whole Steamtown adventure was a mistake. The project should have stayed in non-government hands. Somebody that actually cared about the locomotive and not how they looked to the public or their next election. How many steam locomotives are in operation at Steamtown? There used to be three.
Tim
Guys and Gals.
While the Boiler, firebox, and combustion chamber are major parts there are many many more items that need attention. Cylinders and valves, valve gear, axles, tires, air pumps, springs, and many more. 1361 was not new or even rebuilt when it was placed on the curve. This locomotive has millions of miles on her frame. It was worn out when placed on the curve and it was worn out when it pulled its last car.
All this talk about the locomotive don't forget the tender itself needs major work too.
Put it back together, slap some DGLE on it and display it for everyone to admire. At least the stand in 460 is looking good.
The Prairie Dog Central Railway, just outside Winnipeg in Canada, recently had a new welded boiler built for its 4-4-0 by a company in Saskatoon. It was not easy, since the basic dimensions had to match, nor cheap. Sorry, I don't have the full details readily available, but I think their website will provide more information.
John
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