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Griffon vs Merlin rotation.

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Griffon vs Merlin rotation.

Old 28th Sep 2012, 14:19
  #41 (permalink)  
 
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If you care to get a copy of "633 Squadron" you will clearly see that the Mossie had counter-rotating props.
Hmmmm.

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Old 28th Sep 2012, 16:34
  #42 (permalink)  
 
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Which way to turn?

The current and last few issues of the Rolls-Royce Heritage mag available on the web are instructive. Not only which way to turn but subtle mods to superchargers, turbochargers as a consequence of the handing. Its not just firing order.

Errors, myths, clangers etc would be avoided if only it dawned on folks that the FACTS are available through the Heritage society and even R-R itself rather than perpetuating some nonsense.

The Heritage soc is a separate body to R-R proper and includes Allison and Packard sections. The missives from the Derby and Hucknall branch are notable for their first-hand knowledge and technical authority.

Rather than recycle tired and wrong info why not sign up?
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Old 28th Sep 2012, 17:34
  #43 (permalink)  
 
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Excellent. Thank you sycamore, DaveReidUK and enicalyth. Merlins aren't Etruscan vases. They still exist, still work, and the people who built them and maintained them are still alive. And yet, there is an amazing amount of total borrox spouted by those who should know better, and those who have nothing but an opinion.
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Old 28th Sep 2012, 22:29
  #44 (permalink)  
 
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Look at the F4U Corsair. 4000hp available and it had whacking great long legs to clear that windmill of a four blade prop.

To be pedantic, the F4U-5 got about 3200 horse out of a R2800. Even the F2G only got 3000 horse out of an early R4360.
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Old 29th Sep 2012, 01:56
  #45 (permalink)  
 
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Errors, myths, clangers etc would be avoided if only it dawned on folks that the FACTS are available through the Heritage society and even R-R itself rather than perpetuating some nonsense.
Agreed enicalyth. To put to bed a couple here
Packard Merlins were just the same as their U.K-built counterparts, except that they used U.S. sized nuts, bolts, threads etc
The American engines used the very same British thread system. Packard had to produce all the taps and dies themselves, something they were not set up to do, and delayed actual engine manufacture for some period of time.

Lightning Mate, the Mossie props rotated in the same direction, irrespective of Mark. Your observation would be down to film frame rate as you say. You see the same effect in a film of a car wheel, at some point it will appear to be rotating in the reverse direction compared to its actual rotation. The clip you saw must have been on the very point where this effect takes effect, to coin a phrase. Slight difference in actual prop RPM would give the appearance of reverse rotation. Instructors used to use this strobe effect to determine if students had the RPM set correctly by flying astern and looking through their own prop disc at the students, and determining which direction the students prop appeared to be turning.
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Old 29th Sep 2012, 04:48
  #46 (permalink)  
 
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Thank you very much Brian Abraham. That is a nugget I have been looking for for a long time. I have been led to believe that within the development cycle, parts were essentially interchangeable between UK and US built merlins, but have found nothing authorititive. To have built different versions with either BSW/BSF or SAE threads would have been an incredible procurement SNAFU and led to a logistical and practical nightmare.
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Old 29th Sep 2012, 10:53
  #47 (permalink)  
 
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Very little internally would interchange, due to the differing production methods described earlier. The hand fitting that took place in UK built engines put paid to that.
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Old 29th Sep 2012, 12:27
  #48 (permalink)  
 
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Are you sure, absolutely certain that UK Merlins were all individually hand built by skilled fitters?

"Ford's factory, which was completed in May 1941, was built in two distinct sections to limit potential bomb damage.[nb 10] At first, the factory had difficulty in attracting suitable labour, such that large numbers of women, youths and untrained men had to be taken on. Despite this the first Merlin engine came off the production line one month after the factory's completion, and the production rate was 200 Merlins per week by 1943.[27][67][nb 11] Ford's investment in machinery and the redesign resulted in the 10,000 man-hours needed to produce a Merlin dropping to 2,727 man-hours three years later, while unit cost fell from 6,540 in June 1941 to 1,180 by the war's end. In his autobiography Not much of an Engineer, Sir Stanley Hooker states: "... once the great Ford factory at Manchester started production, Merlins came out like shelling peas. The percentage of engines rejected by the Air Ministry was zero. Not one engine of the 30,400 produced was rejected ...""

Rolls-Royce Merlin - Wikipedia, the free encyclopedia
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Old 29th Sep 2012, 14:37
  #49 (permalink)  
 
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There was film made of flight refuelling trials with a Belfast attempting to fuel from a Victor; not very successfully. As the Belfast throttled back in order to make a fresh stab at the basket one very senior officer in the audience was heard to say that he hadn't realised that the engines could be reversed in flight in order to slow down.

Last edited by Lancman; 29th Sep 2012 at 14:38.
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Old 30th Sep 2012, 01:30
  #50 (permalink)  
 
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Sorry Ken, my point was meant to be relevant to rolls production, not Ford. You are quite right about engines built by Ford. Very little actual fitting required. Pretty much just assembly necessary!
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Old 30th Sep 2012, 05:49
  #51 (permalink)  
 
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Thanks for the clarification
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Old 30th Sep 2012, 15:18
  #52 (permalink)  
 
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one very senior officer in the audience was heard to say that he hadn't realised that the engines could be reversed in flight in order to slow down.
"I thought so little, they rewarded me
by making me the ruler of the Queen's naveee!"
- Sir William Schwenck Gilbert
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Old 29th Jul 2014, 14:06
  #53 (permalink)  
 
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No one has yet mentioned the Griffon with the Contra Prop fitted to Spits, these must have been a dream to fly, all that grunt and no descernable torque effect on t/o or landing, just a lot of willing horses trying to pull all the rivets out..!

Peter R-B
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Old 13th Sep 2015, 08:09
  #54 (permalink)  
 
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The Allison engines in the P38 were turbocharged, the Merlin and Griffon were supercharged

Of course supercharging can be mechanical or via a turbo (turbocharged)
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Old 13th Sep 2015, 16:44
  #55 (permalink)  
 
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The Allison engines in the P38 were turbocharged, the Merlin and Griffon were supercharged
The Allison in the P-38 was both supercharged and turbocharged. Only the "B" model used in airships was unsupercharged.
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