Post War Merlin
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MERLIN TUDOR
Since the Avro Tudors have been mentioned on this thread, I pass on comment made by a friend who as a Flight Engineer, flew on Tudor IV Bs, which from 'Google' I note would be Merlin 623 engines. Apart from the Lincoln wing connection and noise due to no cross-over exhausts, he mentioned problems with the Roots blowers, the F/E's manual spill valves, and cabin ingestion of misting blower oil. He seems mostly to have flown them with the pressurisation system disabled. After the Tudor, The DC6 must have been bliss, I imagine.
Does anyone have any diagrams of the crossover exhaust system used on the North Star Merlins?
As a FAA DEMI at EAL giving oral and practical A&P mechanics exams I examined a highly experienced ex pat Brit down from our YUL base. He was an RAF fitter prewar, worked at BOAC and came to Canada. He had British type ratings on, it seemed, everything. He and I talked airplanes and engines and he said the Merlins had a lot of extra work like washing backfire screens which took a lot of disassembly. Also that crossover meant a lot of extra exhaust plumbing.
I wonder why they didn't use Bristol Hercules on the DC-4M? The TBO quoted here for the Merlin are quite discouraging. Understand the engine choice was made to save dollars in that lean postwar time. So a Bristol engine would have been okay.
While still in school I used to see the Trans Canada North Stars coming into KLGA. Loved their sleek engine look and their sound. Never got to work on any though.
One other question, Did the North Stars/Argonauts have reverse pitch propellers? I know that systemwise they were more DC-6 than DC-4.
As a FAA DEMI at EAL giving oral and practical A&P mechanics exams I examined a highly experienced ex pat Brit down from our YUL base. He was an RAF fitter prewar, worked at BOAC and came to Canada. He had British type ratings on, it seemed, everything. He and I talked airplanes and engines and he said the Merlins had a lot of extra work like washing backfire screens which took a lot of disassembly. Also that crossover meant a lot of extra exhaust plumbing.
I wonder why they didn't use Bristol Hercules on the DC-4M? The TBO quoted here for the Merlin are quite discouraging. Understand the engine choice was made to save dollars in that lean postwar time. So a Bristol engine would have been okay.
While still in school I used to see the Trans Canada North Stars coming into KLGA. Loved their sleek engine look and their sound. Never got to work on any though.
One other question, Did the North Stars/Argonauts have reverse pitch propellers? I know that systemwise they were more DC-6 than DC-4.
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According to Larry Milberry's book "The Canadair North Star", the North Stars had no reverse pitch capability. Most North Stars had 3-bladed props, but a few were fitted with four-bladed props.
As the North Star airliner was designed primarily for Trans Canada Air Lines (TCA), a TCA study team was charged with the responsibility for engine selection. TCA and Canadair were both Crown Corporations, (Federal government backed), and the North Star project was deemed important to the Canadian post-war economy.
Regarding specific engine selection, the list of engines considered: P&W R-2000-9 and R-2800-C; Rolls-Royce RM-14-SM and RM-20-SM
(Merlins) and Griffon; the Bristol HE-10 Hercules; and the Wright R-2600-22. The criteria ultimately led to two finalists; the Rolls-Royce RR-14-SM Merlin, and the Pratt and Whitney R-2800-C. The rated power of the RR Merlin is higher than all the other engines under consideration at altitudes above 20,000 feet (up to at least 25,000 feet), where the maximum possible power is essential for realistic trans-Atlantic service. (It also provided a safe margin of performance whilst flying over the Canadian Rocky Mountains). To quote the TCA selection document: "The cruising power used to obtain equal performance will therefore be at a lower percentage of rated power with the RM-14-SM than with any other engine". TCA also had a history with Rolls-Royce Merlin engines, as TCA operated a fleet of modified AVRO Lancasters, (Lancastrians), employed on their trans-Atlantic passenger and mail- express service.
The engine selection was not without considerable political controversy.
The TCA Merlin cross-over exhaust was designed by TCA engineer M.W. "Mac" MacLeod. The BOAC Argonaut cross-over exhaust evolved from Canadair's research, and was different from TCA's. A full description, replete with photos, is in Larry Milberry's book, which is available at Canavbooks.com.
As the North Star airliner was designed primarily for Trans Canada Air Lines (TCA), a TCA study team was charged with the responsibility for engine selection. TCA and Canadair were both Crown Corporations, (Federal government backed), and the North Star project was deemed important to the Canadian post-war economy.
Regarding specific engine selection, the list of engines considered: P&W R-2000-9 and R-2800-C; Rolls-Royce RM-14-SM and RM-20-SM
(Merlins) and Griffon; the Bristol HE-10 Hercules; and the Wright R-2600-22. The criteria ultimately led to two finalists; the Rolls-Royce RR-14-SM Merlin, and the Pratt and Whitney R-2800-C. The rated power of the RR Merlin is higher than all the other engines under consideration at altitudes above 20,000 feet (up to at least 25,000 feet), where the maximum possible power is essential for realistic trans-Atlantic service. (It also provided a safe margin of performance whilst flying over the Canadian Rocky Mountains). To quote the TCA selection document: "The cruising power used to obtain equal performance will therefore be at a lower percentage of rated power with the RM-14-SM than with any other engine". TCA also had a history with Rolls-Royce Merlin engines, as TCA operated a fleet of modified AVRO Lancasters, (Lancastrians), employed on their trans-Atlantic passenger and mail- express service.
The engine selection was not without considerable political controversy.
The TCA Merlin cross-over exhaust was designed by TCA engineer M.W. "Mac" MacLeod. The BOAC Argonaut cross-over exhaust evolved from Canadair's research, and was different from TCA's. A full description, replete with photos, is in Larry Milberry's book, which is available at Canavbooks.com.
Last edited by evansb; 10th Mar 2014 at 19:42. Reason: ers
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Does anyone have any diagrams of the crossover exhaust system used on the North Star Merlins?
Thanks so much Evansb and noyade. BrianB, will keep trying to get into that website and find thee article. The exhaust crossover is a very nice bit of design work. The required bulge of the top profile of the cowling is less than I would have thought and quite neat. Actually this is a lot neater than the exhaust plumbing on the DC-6 with its myriad of pipes.
No reverse pitch was a problem I imagine in snow. Did any Merlin powered transports have reverse?
Quite surprised that the Merlin had a higher rated cruise power than an R2800 considering the extra 1150 cubic inches of displacement. I shall have to dig into my books about cruise power. I will order that book even though I now have to read using a low-vision reader to blow up type and images.
I worked a lot of DC-4 and DC-6 of various airlines. I thought the R200 was a great engine. It wasn't pushed very hard which probably explains a lot about reliability. One Chilean Airline, CINTA, even regularly used them over the mountains while providing their pax with oxygen. They had the two speed superchargers operational, most companies having locking them in low. So even the straight DC-4 could get up pretty high.
No reverse pitch was a problem I imagine in snow. Did any Merlin powered transports have reverse?
Quite surprised that the Merlin had a higher rated cruise power than an R2800 considering the extra 1150 cubic inches of displacement. I shall have to dig into my books about cruise power. I will order that book even though I now have to read using a low-vision reader to blow up type and images.
I worked a lot of DC-4 and DC-6 of various airlines. I thought the R200 was a great engine. It wasn't pushed very hard which probably explains a lot about reliability. One Chilean Airline, CINTA, even regularly used them over the mountains while providing their pax with oxygen. They had the two speed superchargers operational, most companies having locking them in low. So even the straight DC-4 could get up pretty high.
Last edited by tonytales; 9th Mar 2014 at 01:10.
One Chilean Airline, CINTA, even regularly used them over the mountains while providing their pax with oxygen. They had the two speed superchargers operational, most companies having locking them in low. So even the straight DC-4 could get up pretty high.
On a similar, but Argonaut-related topic...
My late uncle, Dick Chester, was a "flying spanner" on the Argonaut for BMA, and had some amusing tales, usually related at large family gatherings to much amusement.
Apparently, the pressurisation was quite "leaky", and did occasionally cause problems for some passengers, one actually hallucinating, and being convinced that a skier was outside one of the windows, trying to get in, as they crossed The Alps. And the climb to cross high terrain was always an "interesting" experience, with one captain willing the aircraft along with a frequent "come on, old gal..."
The "high level blowers", as uncle called them, would cause the engine note to change alarmingly when they cut in, causing consternation among the nervous.
Capt Belcher (who was F/O on the Argonaut) told me at my uncle's wake that there were clear signs on the flight desk that the fuselage actually "stretched" when pressurised. I can't recall the precise details, but it related to the seat fit/adjustment on the rails, which varied from on the ground to in the air.
I'm not sure I could stand five noisy and slow hours back from Palma to Manchester on one, as the ill-fated 'HG had almost done before it's misfortune at Stockport. Passengers suffered for their pleasure in those days. And, at the front, there were all the challenges of "unusual" Spanish ATC, basic navaids, frequent SRAs, marginal performance, and hazardous terrain. No "magenta line" in those days...
On a similar, but Argonaut-related topic...
My late uncle, Dick Chester, was a "flying spanner" on the Argonaut for BMA, and had some amusing tales, usually related at large family gatherings to much amusement.
Apparently, the pressurisation was quite "leaky", and did occasionally cause problems for some passengers, one actually hallucinating, and being convinced that a skier was outside one of the windows, trying to get in, as they crossed The Alps. And the climb to cross high terrain was always an "interesting" experience, with one captain willing the aircraft along with a frequent "come on, old gal..."
The "high level blowers", as uncle called them, would cause the engine note to change alarmingly when they cut in, causing consternation among the nervous.
Capt Belcher (who was F/O on the Argonaut) told me at my uncle's wake that there were clear signs on the flight desk that the fuselage actually "stretched" when pressurised. I can't recall the precise details, but it related to the seat fit/adjustment on the rails, which varied from on the ground to in the air.
I'm not sure I could stand five noisy and slow hours back from Palma to Manchester on one, as the ill-fated 'HG had almost done before it's misfortune at Stockport. Passengers suffered for their pleasure in those days. And, at the front, there were all the challenges of "unusual" Spanish ATC, basic navaids, frequent SRAs, marginal performance, and hazardous terrain. No "magenta line" in those days...
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I remember when somewhat younger, my father commented that when he travelled fairly regularly on North Star's, they would arrive at their destinations on four while the DC 4's operated by the competition often landed with one feathered. Think the destination he referred to was Hawaii. If any of this is incorrect, it is my failing memory at fault, not the source.
tonytales,
Purely for the sake of accuracy, The difference in CID between Merlin and R2800 is somewhat larger than 750 cubes.
The Merlin, whether constructed by Rolls-Royce, Ford or Packard, had a CID of 1649, generally rounded up to 1650. This side of the pond, it is stated as 27 litres.
The R2800 has a CID of 2800 (45.8 litres) therefore having a capacity 1150 CI (18.8 litres) greater than a Merlin.
Camlobe
tonytales,
Purely for the sake of accuracy, The difference in CID between Merlin and R2800 is somewhat larger than 750 cubes.
The Merlin, whether constructed by Rolls-Royce, Ford or Packard, had a CID of 1649, generally rounded up to 1650. This side of the pond, it is stated as 27 litres.
The R2800 has a CID of 2800 (45.8 litres) therefore having a capacity 1150 CI (18.8 litres) greater than a Merlin.
Camlobe
Camlobe,
Shame on me for an elementary arithmetic mistake. I shall blame my eyesight. It only make the cruising power of the Merlin more spectacular as both enigines seem to have been cranking in the area of 1000 hp in cruise, the Merlin needing more revs however. I think the efficiency of the Rolls superchargers may also explain some of that.
Shame on me for an elementary arithmetic mistake. I shall blame my eyesight. It only make the cruising power of the Merlin more spectacular as both enigines seem to have been cranking in the area of 1000 hp in cruise, the Merlin needing more revs however. I think the efficiency of the Rolls superchargers may also explain some of that.
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Merlin Reverse pitch props
I am "almost" certain that the BOAC Argonaut had reverse pitch props.
In a previous life I was stationed at Kai Tak in 1950 and recall the Argonauts arriving and departing every week.
Our "office" was close to the slipway at the threshold of Rw 31. This was the old Kai Tak not the checkerboard Kai Tak. Although Rw 13 was the preferred runway for landing I recall an Argonaut approach and landing on Rw 31. I have no idea the approach limits but once crossed the sea wall a go around was not an option. The Argonaut touched down on the spot and I remember thinking he must glad he had reverse pitch with Lion Rock at the other end.
Another day a USAF C54 left his main wheels at the sea wall and flopped onto the runway. All ran away safely.
In a previous life I was stationed at Kai Tak in 1950 and recall the Argonauts arriving and departing every week.
Our "office" was close to the slipway at the threshold of Rw 31. This was the old Kai Tak not the checkerboard Kai Tak. Although Rw 13 was the preferred runway for landing I recall an Argonaut approach and landing on Rw 31. I have no idea the approach limits but once crossed the sea wall a go around was not an option. The Argonaut touched down on the spot and I remember thinking he must glad he had reverse pitch with Lion Rock at the other end.
Another day a USAF C54 left his main wheels at the sea wall and flopped onto the runway. All ran away safely.
I seem to recall that Capt. Cramp's book on the history of BMA mentions Argonauts landing at Burnaston (the former Derby Aviation base) and using reverse pitch. Without it, I doubt that they would have made it into the small-ish grass airfield that Cramp describes as "pocket-sized".
Last edited by Midland 331; 10th Mar 2014 at 12:33.
If my memory serves me right - and it was 40 years ago so I'm not taking any bets - Paul Jameson, who built the original rolling chassis, was aggrieved that John Dodds was claiming it was a Merlin and vowed to build one that really was a Merlin. I remember seeing a b/w picture in a magazine showing a six wheeled chassis with, I think, a temporary seat mounted on top but after a so far brief google I haven't found anything.
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DC4 M at Redhill
Wasn't one maybe two stored at Redhill over a winter in the early 60's. One Pruner wrote about the ruts he made. Don't think it was BM but an earlier version of Tradewinds. Alan
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Last Argonaut at Redhill
Yes, that was probably me. Although I was on Britannias at the time, two of us who had flown G-ALHM within the previous year, had authorisation to move it from Redhill to Castle Donnington on 09MAR66.
During 1964 and 1965, we operated as Air Links. A core group consisting of about four or five; the owner, boss, and admin, and then as far as I recall, a group of engineers, pilots, and a man at Redhill who had the engineering and catering equipment stores. Probably around twenty or so cabin crew available. Personally, I never had a roster or any organised work pattern. I'm fairly sure that all of us were on individually negotiated self employed contracts. A nucleus of engineers had a small office in the 'Beehive' at Gatwick. Main maintenance was Dan Air at Lasham, and I think Aviation Traders at Gatwick. In other words, we were not an Airline organisation on the scale of the other C4 operator, Derby Airways at Burnaston. The four C4 Argonauts ( and one Hermes ) that I knew to be operated ad-hoc by Airlinks; G-ALHW was in freight config, and G-ALHI, G-ALHT, and G-ALHM, were in passenger config. We had nine pilots cleared as Captain, some of whom may have been freelancing for more than one operator. Probably not as many as nine co-pilots. I recall one co-pilot who wore a different coloured uniform with three rings, because he was also a DC3 captain for somebody. One captain flew pre WW2, one was Navy and probably WW2. The others I'm fairly sure were long-time 'Merlinists' from the world of Spitfires and Lancasters. Two at least are mentioned in books. One I noted had a half page obit in the Telegraph. I'm not in a place to check my notes, but I think one or more of the four Aircraft post BOAC had been through the Rhodesian Air Force. The owner of Air Links launched Transglobe sometime in 1965. As far as the pilots I ever flew with or knew, only four of us applied to stay on and become salaried employees.
During 1964 and 1965, we operated as Air Links. A core group consisting of about four or five; the owner, boss, and admin, and then as far as I recall, a group of engineers, pilots, and a man at Redhill who had the engineering and catering equipment stores. Probably around twenty or so cabin crew available. Personally, I never had a roster or any organised work pattern. I'm fairly sure that all of us were on individually negotiated self employed contracts. A nucleus of engineers had a small office in the 'Beehive' at Gatwick. Main maintenance was Dan Air at Lasham, and I think Aviation Traders at Gatwick. In other words, we were not an Airline organisation on the scale of the other C4 operator, Derby Airways at Burnaston. The four C4 Argonauts ( and one Hermes ) that I knew to be operated ad-hoc by Airlinks; G-ALHW was in freight config, and G-ALHI, G-ALHT, and G-ALHM, were in passenger config. We had nine pilots cleared as Captain, some of whom may have been freelancing for more than one operator. Probably not as many as nine co-pilots. I recall one co-pilot who wore a different coloured uniform with three rings, because he was also a DC3 captain for somebody. One captain flew pre WW2, one was Navy and probably WW2. The others I'm fairly sure were long-time 'Merlinists' from the world of Spitfires and Lancasters. Two at least are mentioned in books. One I noted had a half page obit in the Telegraph. I'm not in a place to check my notes, but I think one or more of the four Aircraft post BOAC had been through the Rhodesian Air Force. The owner of Air Links launched Transglobe sometime in 1965. As far as the pilots I ever flew with or knew, only four of us applied to stay on and become salaried employees.
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On reflection, I forgot to mention above that we occasionally carried a navigator if legally required. Again, would be on a freelance basis. I recall one co-pilot who also had a nav licence, didn't show up for a nav duty trip out of Gatwick to the Far East, and turned out to be on a trip to Canada for another company.......oops
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If I remember correctly the Meteor did not have any Supercharger, and a slight variation on piston dimension compared with the Merlin, there are still a lot of Meteors around and can be picked up pretty cheaply,
I once had a pair of Sea-Griffon engines still attached to seagoing gearboxes, thing is they were also attached to a bloody great reduction box as well as the Forward/reverse system to allow the connection to the Sea churning props, plus they had a big square marinised sump for submerged oil-pump recovery and distribution of lubricants, they weighed about 1.7 tonnes each in that guise, as well as all the G/box system the Superchargers were upside down when compared with the Flying Griffons to allow the cold fresh air from the top of the boat to get into the engine, with all that it would have been too much work to convert them to either Fly or power some sort of land craft, but what piece of engineering for Naval use. I bet they were thirsty rascals too!
Peter R-B
Lancashire
I once had a pair of Sea-Griffon engines still attached to seagoing gearboxes, thing is they were also attached to a bloody great reduction box as well as the Forward/reverse system to allow the connection to the Sea churning props, plus they had a big square marinised sump for submerged oil-pump recovery and distribution of lubricants, they weighed about 1.7 tonnes each in that guise, as well as all the G/box system the Superchargers were upside down when compared with the Flying Griffons to allow the cold fresh air from the top of the boat to get into the engine, with all that it would have been too much work to convert them to either Fly or power some sort of land craft, but what piece of engineering for Naval use. I bet they were thirsty rascals too!
Peter R-B
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As a child in the 1950's I flew from Singapore to Heathrow in a BOAC Argonaut -it was the year Don Cockle fought Rocky Marciano. Turned back to Singapore with engine failure.Engine cowling fell off between Kalang airport and Changi when being ferried.Reached Karachi then turned back for another engine change,took off again and turned back again to change another engine. Flying was indeed an adventure in those days.