Post War Merlin
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Merlin Chevy
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Mike Feeney, at skyviking.net, states that the Canadair C-4/DC-4M North Star/Argonaut did indeed have reversible pitch propellers. Equipped with Hamiltion-Standard "Hydromatic" propellers, the props had the fine-pitch stops moved so as to enable reverse pitch.
Mr. Feeney also concludes that, after considering a myriad of operational conditions, TCA was correct in selecting the Rolls Royce Merlin engine, as a C-4 powered Merlin was 30% faster than the radial engine powered DC-4, plus the Canadair DC-4M had a much higher service ceiling and a lower specific fuel consumption, given a higher power setting. Note that the 622 Merlin was more robust than the war-time Spitfire Merlin. Regardless of Rolls-Royce's efforts in bolstering the Merlin for TCA, after the first year of airline service, it became obvious that the Merlins were maintenance intensive. TCA warranty claims resulted in RR agreeing to produce a quantity of 622 Merlins at a reduced cost as compensation.
For block-to-block times and specific fuel consumption rates, an early Douglas DC-6 is a fair comparison to the Canadair DC-4M. (Bets are off in tropical climes and in a -40 Edmonton cold start).
Cost-per-mile determination? Nearly impossible, as most BOAC Argonaut flights and some early TCA North Star flights were all first-class configuration, complete with berths, hot meals served on porcelain china and silver-ware, plus the services of a purser! Navigators, Radio Operators and the occasional Engineer were de rigueur aircrew as well.. In the mid-fifties, TCA reconfigured several North Stars to a denser all-coach (economy-class configuration) for inclusive Canadian trans-continental service, with a two-pilot and single stewardess aircrew being standard.
In rain, sleet, snow, heat and lightning, the North Star performed yeoman service on many regional high-density routes, such as the Toronto-Montreal; Toronto-Ottawa-Montreal; Toronto-Chicago; Montreal-New York; and the ever popular Toronto-New York route.
Below is a photo capturing a classic 3-bladed, cross-over exhaust mod, "TCA North Star", in the twilight of her long and arduous career. Sitting on a snow covered apron in the deep dark cold of a Canadian winter, (circa 1959-60). 10 years previous, she was deemed the fastest way to cross the Atlantic. Now she awaits, perhaps for the last time, a load of passengers she will fly to Chicago-Midway... after which her interior will be gutted and converted into freighter configuration. Few, if anyone, will lament her passing..
Mr. Feeney also concludes that, after considering a myriad of operational conditions, TCA was correct in selecting the Rolls Royce Merlin engine, as a C-4 powered Merlin was 30% faster than the radial engine powered DC-4, plus the Canadair DC-4M had a much higher service ceiling and a lower specific fuel consumption, given a higher power setting. Note that the 622 Merlin was more robust than the war-time Spitfire Merlin. Regardless of Rolls-Royce's efforts in bolstering the Merlin for TCA, after the first year of airline service, it became obvious that the Merlins were maintenance intensive. TCA warranty claims resulted in RR agreeing to produce a quantity of 622 Merlins at a reduced cost as compensation.
For block-to-block times and specific fuel consumption rates, an early Douglas DC-6 is a fair comparison to the Canadair DC-4M. (Bets are off in tropical climes and in a -40 Edmonton cold start).
Cost-per-mile determination? Nearly impossible, as most BOAC Argonaut flights and some early TCA North Star flights were all first-class configuration, complete with berths, hot meals served on porcelain china and silver-ware, plus the services of a purser! Navigators, Radio Operators and the occasional Engineer were de rigueur aircrew as well.. In the mid-fifties, TCA reconfigured several North Stars to a denser all-coach (economy-class configuration) for inclusive Canadian trans-continental service, with a two-pilot and single stewardess aircrew being standard.
In rain, sleet, snow, heat and lightning, the North Star performed yeoman service on many regional high-density routes, such as the Toronto-Montreal; Toronto-Ottawa-Montreal; Toronto-Chicago; Montreal-New York; and the ever popular Toronto-New York route.
Below is a photo capturing a classic 3-bladed, cross-over exhaust mod, "TCA North Star", in the twilight of her long and arduous career. Sitting on a snow covered apron in the deep dark cold of a Canadian winter, (circa 1959-60). 10 years previous, she was deemed the fastest way to cross the Atlantic. Now she awaits, perhaps for the last time, a load of passengers she will fly to Chicago-Midway... after which her interior will be gutted and converted into freighter configuration. Few, if anyone, will lament her passing..
Last edited by evansb; 21st Mar 2014 at 00:11. Reason: clarification, dramatization, emphasis, and technoficaction
Found it! There are some Merlin powered vehicles on page 2 and 3 of this thread: http://www.pprune.org/jet-blast/4103...yces-go-2.html
Including John Dodd's 'The Beast' and a more recent built version.
Including John Dodd's 'The Beast' and a more recent built version.
Thanks. A lot of good info there regarding engine choice. The Rolls Merlin powered Canadair DC-4M would certainly be faster than the standard Pratt R-2000 powered Douglas DC-4/C-54. Although the Rolls 620 series Merlin engine had fewer CI in displacement it provided a cruise power of 1,135 hp @ 2,850 rpm @ 23,500 ft in high blower. The Pratt R-2000 only made 700 hp @ 2,150 rpm @ 21,500 ft in high blower in cruise. Of course the the Douglas DC-4/C-54 was not pressurized so wouldn't go that high to spare the pax hypoxia. So the Rolls Merlin was a better choice certainly than the Pratt R-2000. Looked a lot better too. Fuel consumption in cruise for the Pratt R-2000 was 0.42 lb/hr/hp versus 0.45 for the Merlin in cruise. R-2000 was more economical per hour but mainly due to its lower power and, being slower, would have burned more in total.
The high revs and higher boost contributed to the Merlin's lower TBO.
The Bristol Hercules powers matched the Merlin but its weight (760 series) was 600 lbs more so that would have been 2,400 lbs more per aircraft. The R-2000 was the lightest at 1,595 lb, the Merlin 620 series @ 1,720 lbs and the Hercules 780 series @ 2,345 lbs.
Interestingly, Canadair did produce one Pratt R-2800 powered version. Believe it was for Canadian Government VIP transport. Would it have been a DC-6M?
Starting any piston engine at negative temperatures was interesting. The Bristol rep in New York (we were working Britannias) told us of trying to operate Bristol Freighters up North in Canada. He said you could not even pull a cold-soaked Hercules with its sleeve valves through unless it was preheated. Our South American customers used to regularly burn out starters and induction vibrators or ice the plugs trying to start engines in a much milder New York. No experience with Merlins. Were they harder to start?
The high revs and higher boost contributed to the Merlin's lower TBO.
The Bristol Hercules powers matched the Merlin but its weight (760 series) was 600 lbs more so that would have been 2,400 lbs more per aircraft. The R-2000 was the lightest at 1,595 lb, the Merlin 620 series @ 1,720 lbs and the Hercules 780 series @ 2,345 lbs.
Interestingly, Canadair did produce one Pratt R-2800 powered version. Believe it was for Canadian Government VIP transport. Would it have been a DC-6M?
Starting any piston engine at negative temperatures was interesting. The Bristol rep in New York (we were working Britannias) told us of trying to operate Bristol Freighters up North in Canada. He said you could not even pull a cold-soaked Hercules with its sleeve valves through unless it was preheated. Our South American customers used to regularly burn out starters and induction vibrators or ice the plugs trying to start engines in a much milder New York. No experience with Merlins. Were they harder to start?
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Merlin cold start.
My engine manual shows that the "worth" oil dilution system could be
fitted to the the Merlin 620 & 621 for cold operations.Cold start in temperatures down to -40C were possible.
fitted to the the Merlin 620 & 621 for cold operations.Cold start in temperatures down to -40C were possible.
Starting any piston engine at negative temperatures was interesting. The Bristol rep in New York (we were working Britannias) told us of trying to operate Bristol Freighters up North in Canada. He said you could not even pull a cold-soaked Hercules with its sleeve valves through unless it was preheated.
Interestingly, Canadair did produce one Pratt R-2800 powered version. Believe it was for Canadian Government VIP transport. Would it have been a DC-6M?
Planemike
esa aardvark mentioned oil dilution. There was provision for it on some of the L-1049D's but it was deactivated. I believe the Navy R7V Connies I serviced at Lockheed New York that were modified for use down in the Antarctic had it activated. They also had a combustion heaters in the nacelle for preheating the oil tank.
(think the Connies were El Piasano and Roadrunner)
Problem with oil dilution, as I recall from hearing, not having ever used it, is that the gasoline mixing with the oil loosens sludge throughout the engine. There is a lot of sludge in the oil deposited in such places as the prop dome on Hydromatics and in sludge caches in the crankshafts and other places in some engines. The dilution freed up some of this sludge and it was required you pull the oil screens after use of oil dilution.
I deeply sympathize with anyone pulling sump plugs and oil screens in -40F as it was bad enough at +5F.
(think the Connies were El Piasano and Roadrunner)
Problem with oil dilution, as I recall from hearing, not having ever used it, is that the gasoline mixing with the oil loosens sludge throughout the engine. There is a lot of sludge in the oil deposited in such places as the prop dome on Hydromatics and in sludge caches in the crankshafts and other places in some engines. The dilution freed up some of this sludge and it was required you pull the oil screens after use of oil dilution.
I deeply sympathize with anyone pulling sump plugs and oil screens in -40F as it was bad enough at +5F.
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For over 70 years, during winter in Alaska and Northern Canada, the Herman Nelson flameless pre-heater is employed to assist in starting aircraft that have been cold soaked in extreme cold temperatures. Two models I've seen are either diesel/kerosene powered or avgas powered. The heaters are often mounted on skis/skids. The Herman Nelson is also used by Canadian based Kenn Borek Air in their Antarctic operations.
Below is a photo of a sled mounted Herman Nelson heater, warming a Superior Airways Beechcraft Model 18, (ex RCAF C-45 Expeditor),:
Below is a photo of a sled mounted Herman Nelson heater, warming a Superior Airways Beechcraft Model 18, (ex RCAF C-45 Expeditor),:
Last edited by evansb; 30th Mar 2014 at 00:52.
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Re the climb out performance of the Argonaut, here is a passage from ex-BOAC/BA Captain, Peter Duffy's book, "Comets and Concordes (and those I flew before):" heading is "Argonaut departures;" "The departure from Rio was usually on the direct route north to Recife, and not via the harbour entrance. This saved conflict with air traffic at the city airport, and also mileage, but involved flight up a valley over rising ground to the town of Petropolis. The ground rose to match the climb rate of a fully loaded Argonaut, and it seemed as if we were flying up the main street of this town to just clear a large church.........I do not remember many dreams, but have a recurrent vision of this departure, with hills on both sides of the a/c, and involving weaving to avoid roof tops" (!)
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Short stacks vs. crossover exhaust
The Merlin/Argonaut exhaust mod had a parallel in R-2600 installations. The TBM (nee TBF) had a collector ring, like many radials; but the same engine in the B-25 had short stacks. The difference in noise level is dramatic.
But postwar most B-25s had a half-collector ring installed, for a different reason: the short shacks on the upper cylinders were rain collectors, leading to exhaust valve rusting and failure. Engine covers were mandatory ground equipment.
The half-ring mod alleviated this problem, exhausting low on the outboard side. But the lower cylinders retained their short stacks, and so remained noisemakers.
So if you plan on a joy ride in a B-25, do yourself a BIG favor and stop off at the local apothecary for some ear plugs!
But postwar most B-25s had a half-collector ring installed, for a different reason: the short shacks on the upper cylinders were rain collectors, leading to exhaust valve rusting and failure. Engine covers were mandatory ground equipment.
The half-ring mod alleviated this problem, exhausting low on the outboard side. But the lower cylinders retained their short stacks, and so remained noisemakers.
So if you plan on a joy ride in a B-25, do yourself a BIG favor and stop off at the local apothecary for some ear plugs!
I received my copy of "The Canadair North Star" by Larry Mileberry. It is an excellent read and very informative. A considerable section covers the choice and operating experience of the Rolls Royce Merlin 620 series as the powerplant.
The reasons for choosing the Merlin are clearly laid out and are persuasive. It offered better power at the higher cruising altitude desired than the Pratt R-2000 or even the R-2800. That being said, operationally the choice turned out to be not as good as expected.
First was the sheer noise. Even with the crossover exhaust system which only came along years after the aircraft went into service, it was still noisier inside than than the DC-6. The system did reduce it almost to tolerable levels.
Second, the engine was not as durable as the radials for the day in and day out slog of commercial service. I use the book which quotes authoritative sources. Ultimately, TCA was forced to reduce the power setting in cruise which negated the original reasons for the choice.
The TBO of the Merlin was not up to that of the Pratts. Spare usage and costs, particularly for pistons, rings and cylinder liners was particularly high. Fortunately for Trans Canada (TCA), Rolls had entered into an agreement with TCA known as "Won't be sorry" that committed Rolls to ensuring that the Merlin spares cost would not be no more than those for the radials. In effect, Rolls subsidized the use of the Merlin. This agreement obviously paid off in later years with the choice of the Dart for the Viscounts, Tyne for the Vanguards, Conways for the DC-8 and RB-211 for the L-1011.
It is unclear if BOAC had a similar agreement for their Argonauts and certainly the later operators would have paid heavily.
This does not imply that the Merlin was a bad engine for the North Star as they and their Argonaut cousins did yeoman service all over the world. It was just more expensive an engine to operate.
One final tidbit clearing the matter of reversible props. TCA and the RCAF North Stars did not have reverse pitch props fitted. BOAC's Argonauts did. This explains why some commentators have one experience and others a different one. Depends on who the original operator was.
I recommend the book to anyone wanting insight into a great aircraft and engine.
I still remember being a young teen and leaning over the railing on the observatin deck at KLGA and seeing the elegant North Stars taxiing in and out. They had an announcer in those days on a PA who claimed that American and TCA had daily races from YYZ down to NYC. American with their DC-6 and TCA of course with the North Stars. Sheer hype of course but great fun.
The reasons for choosing the Merlin are clearly laid out and are persuasive. It offered better power at the higher cruising altitude desired than the Pratt R-2000 or even the R-2800. That being said, operationally the choice turned out to be not as good as expected.
First was the sheer noise. Even with the crossover exhaust system which only came along years after the aircraft went into service, it was still noisier inside than than the DC-6. The system did reduce it almost to tolerable levels.
Second, the engine was not as durable as the radials for the day in and day out slog of commercial service. I use the book which quotes authoritative sources. Ultimately, TCA was forced to reduce the power setting in cruise which negated the original reasons for the choice.
The TBO of the Merlin was not up to that of the Pratts. Spare usage and costs, particularly for pistons, rings and cylinder liners was particularly high. Fortunately for Trans Canada (TCA), Rolls had entered into an agreement with TCA known as "Won't be sorry" that committed Rolls to ensuring that the Merlin spares cost would not be no more than those for the radials. In effect, Rolls subsidized the use of the Merlin. This agreement obviously paid off in later years with the choice of the Dart for the Viscounts, Tyne for the Vanguards, Conways for the DC-8 and RB-211 for the L-1011.
It is unclear if BOAC had a similar agreement for their Argonauts and certainly the later operators would have paid heavily.
This does not imply that the Merlin was a bad engine for the North Star as they and their Argonaut cousins did yeoman service all over the world. It was just more expensive an engine to operate.
One final tidbit clearing the matter of reversible props. TCA and the RCAF North Stars did not have reverse pitch props fitted. BOAC's Argonauts did. This explains why some commentators have one experience and others a different one. Depends on who the original operator was.
I recommend the book to anyone wanting insight into a great aircraft and engine.
I still remember being a young teen and leaning over the railing on the observatin deck at KLGA and seeing the elegant North Stars taxiing in and out. They had an announcer in those days on a PA who claimed that American and TCA had daily races from YYZ down to NYC. American with their DC-6 and TCA of course with the North Stars. Sheer hype of course but great fun.
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Just to add to the info, an email I received from David Birch of enginehistory some years ago.
You may find the following of interest Aircraft Engine Performance Analysis at Rolls-Royce
In 1945 Rolls-Royce changed its mark number system for its transport and civil engines and allocated the 500-range to the single-stage engines and 600 to the two-stage engines. These COMMERCIAL engines included engines sold overseas to airlines and airforces, ie, they were not ordered on a UK government contract. A great number of these engines were Mk.24s, and these were given the commercial mark number 500. Just to confuse you, if an airline had bought ex-RAF Lancastrians and Yorks with Mk.24 engines in them, then they retained that mark number. But if they purchased spare engines from Rolls-Royce, or ordered new Yorks from Avro then they had Mk.500 engines installed. Many second-hand Lancastrains and Yorks had the transport version of the Mk.24 fitted. This was the Mk.T24-2 in military service AND civil service until the new numbering system was initiated. On overhaul the civil ones usually had their mark number changed to 500.
Any Merlin with a mark number of between 500 and 599 is one of the 500-series.There were a number of them, the highest being 549, but most were variants of the Mk.500 with a dash number to denote the operator and the slight installational differences. Most of the 500-series marks were only experimental/development engines. Mk.502 was the only other 500-series mark that entered service.
There were hundreds of 500-series engines, the vast majority installed in Lancastrians and Yorks. The Mk.500 (without a suffix) was for BOAC, Mk.500-2 was for British South American Airways. The 500-29 and 500-45 engines you mention were installed in the Spanish-built Heinkels and Messerschmitts, the dash number indicating a certain build standard appropriate to those aircraft. There were many more. Remember those Argentinian Lincolns? - they had 621-15 engines.
Any Merlin with a mark number of between 500 and 599 is one of the 500-series.There were a number of them, the highest being 549, but most were variants of the Mk.500 with a dash number to denote the operator and the slight installational differences. Most of the 500-series marks were only experimental/development engines. Mk.502 was the only other 500-series mark that entered service.
There were hundreds of 500-series engines, the vast majority installed in Lancastrians and Yorks. The Mk.500 (without a suffix) was for BOAC, Mk.500-2 was for British South American Airways. The 500-29 and 500-45 engines you mention were installed in the Spanish-built Heinkels and Messerschmitts, the dash number indicating a certain build standard appropriate to those aircraft. There were many more. Remember those Argentinian Lincolns? - they had 621-15 engines.
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Merlin 500 series: Two Speed - Single Stage Supercharger - Identical to Merlin T24-2 but termed Merlin 500 for Civil or Commercial operator
500 B.O.A.C. Lancastrian York
500-2 B.S.A.A. Lancastrian York
500-3 Alitalia Lancastrian
500-4 Skyways Limited Lancastrian York
500-5 F.A.M.A. Lancastrian York
500-6 Silver City Airways Lancastrian
500-20 Fiat G.59
500-21 Flight Re-Fuelling Ltd Lancastrian
500-23 Egyptian Government Lancastrian
500-29 CASA C.2111
500-45 Hispano HA-1112
501 T.C.A. Lancastrian
502
502-1 B.O.A.C. York
504 No Production
530 No Production
539 No Production
549 No Production
Merlin 600 series: Two Speed - Two Stage Supercharger
600 Tudor Prototype (Converted to Merlin 102A)
604 Argentine Government
620 T.C.A. & RCAF D.C.4 M.1
621-1 B.O.A.C. Tudor II
621-2 B.S.A.A. Tudor II, IV, V
621-5 Flota Aerea Mercante Tudor
621-15 Argentine Government Lincoln
622 T.C.A. (Domestic) D.C.4 M.2
623-2 B.S.A.A. Tudor IV
624-10 T.C.A. (Atlantic) D.C.4 M.2
625 No Production
626-1 B.O.A.C. Canadair IV C.4
626-12 Canadian Pacific Canadair IV C.4
630 No Production
631 No Production
640 No Production
641 No Production
Merlin 700 series: Two Speed - Two Stage Supercharger
724-1 B.O.A.C. Similar to Merlin 626-1 with cooling mod.
724-1C B.O.A.C. As Merlin 724-1 with crossover exhaust
722-10 Canadair As Merlin 622-10 with cooling mod.
724-10 Canadair As Merlin 624-10 with cooling mod.
Source: Rolls-Royce Production Drawing Office, February 1953.
500 B.O.A.C. Lancastrian York
500-2 B.S.A.A. Lancastrian York
500-3 Alitalia Lancastrian
500-4 Skyways Limited Lancastrian York
500-5 F.A.M.A. Lancastrian York
500-6 Silver City Airways Lancastrian
500-20 Fiat G.59
500-21 Flight Re-Fuelling Ltd Lancastrian
500-23 Egyptian Government Lancastrian
500-29 CASA C.2111
500-45 Hispano HA-1112
501 T.C.A. Lancastrian
502
502-1 B.O.A.C. York
504 No Production
530 No Production
539 No Production
549 No Production
Merlin 600 series: Two Speed - Two Stage Supercharger
600 Tudor Prototype (Converted to Merlin 102A)
604 Argentine Government
620 T.C.A. & RCAF D.C.4 M.1
621-1 B.O.A.C. Tudor II
621-2 B.S.A.A. Tudor II, IV, V
621-5 Flota Aerea Mercante Tudor
621-15 Argentine Government Lincoln
622 T.C.A. (Domestic) D.C.4 M.2
623-2 B.S.A.A. Tudor IV
624-10 T.C.A. (Atlantic) D.C.4 M.2
625 No Production
626-1 B.O.A.C. Canadair IV C.4
626-12 Canadian Pacific Canadair IV C.4
630 No Production
631 No Production
640 No Production
641 No Production
Merlin 700 series: Two Speed - Two Stage Supercharger
724-1 B.O.A.C. Similar to Merlin 626-1 with cooling mod.
724-1C B.O.A.C. As Merlin 724-1 with crossover exhaust
722-10 Canadair As Merlin 622-10 with cooling mod.
724-10 Canadair As Merlin 624-10 with cooling mod.
Source: Rolls-Royce Production Drawing Office, February 1953.
It does look peculiar to see a DC-6 vertical fin with a deicer boot on it.
The C-5 must have been fast. We worked a straight DC-6 (not an A or B) that had been re-engined with CB-16 for South American work. It did shake a lot on runup though but was allegedly quite fast.
The C-5 must have been fast. We worked a straight DC-6 (not an A or B) that had been re-engined with CB-16 for South American work. It did shake a lot on runup though but was allegedly quite fast.
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The Canadair C-5 certainly flew faster and higher than a Douglas C-54, the Canadair C-5 had a max. speed of 320 mph (278 kts), a cruise of 303 mph (263 kts) with a service ceiling of 26,000 ft. and a GTOW of 86 000 lbs. (Heavier than the C-54 and the North Star/Argonaut)
The Rolls-Royce powered DC-4Ms flew even faster and higher than the C-5. The Canadair C-5, however, had a longer range and had a much less noisy cabin. It entered service in 1950 and was the RCAFs premier VIP transport.
She served for 17 years and was sold to an American buyer, where it was registered as N17599.
The Rolls-Royce powered DC-4Ms flew even faster and higher than the C-5. The Canadair C-5, however, had a longer range and had a much less noisy cabin. It entered service in 1950 and was the RCAFs premier VIP transport.
She served for 17 years and was sold to an American buyer, where it was registered as N17599.
