Greatest aviation myth this site “de-bunked”.

[Deleted member 68059]

As I understand the two companies simply took different ways of manufacturing an engine to the required tolerances.

In the UK, with cheaper labour and (generally) shorter production volumes they'd produce components to looser tolerances, then after manufacture get these groups into matching assemblies with the required tolerance.

In the US, with more expensive labour, larger production runs and presumably a more highly developed capital raising system they'd spend more on production machinery that produced tighter tolerances in the first place, without requiring the manual sorting and matching.

Both were valid for their particular circumstances.

I`d been waiting for someone to lay down all the Ford, RR and Packard drawings next to eachother and check the tolerances. Seems like you must have done that yourself, Please reply with drawing #`s and tolerances.

All the first 2-stage packards were made with conversion kits which Derby shipped to packard. What a miracle they all fitted right onto the Packard engines.

(NARA-6550737)

 

[Shortround6]

All the first 2-stage packards were made with conversion kits which Derby shipped to packard. What a miracle they all fitted right onto the Packard engines.

No Miracle, Packard recruited ex Willys-Knight sleeve valve engine workers to meticulously hand fit the parts (joke)
we can't let this argument die simply because of truth.

 

[rochie]

I`d been waiting for someone to lay down all the Ford, RR and Packard drawings next to eachother and check the tolerances. Seems like you must have done that yourself, Please reply with drawing #`s and tolerances.

All the first 2-stage packards were made with conversion kits which Derby shipped to packard. What a miracle they all fitted right onto the Packard engines.

(NARA-6550737)

Us bumbling, dumb, unskilled Brits must've got lucky eh ?

 

[rochie]

also all that hand fitting, filing and fettling probably weakened everything and thats why all British aircraft were fragile too !

 

[Reluctant Poster]

Caidin was notorious for taking things out of context as well as outright fabricating "information" to sensationalized his articles and publications.
So in the case of the P-38, he took a bit of propaganda and sensationalized it to his benefit and we've been stuck with that Caidinism ever since...

Here's an article from 1945 extolling the virtues of The Fork Tailed Devil
LiTOT: The Fork-Tailed Devil
The article also includes the myth that the P38 was the first US plane to shoot down an enemy plane.

 

[swampyankee]

Reply

Mr. Connery is Bond, James Bond. Roger Moore is the Saint. But John Cleese is the best Q hands down.
Who is Daniel Craig?

One of the actors who portrayed Bond after Sean Connery, and likely the best of them.

 

[SaparotRob]

Here's an article from 1945 extolling the virtues of The Fork Tailed Devil
LiTOT: The Fork-Tailed Devil
The article also includes the myth that the P38 was the first US plane to shoot down an enemy plane.

Regarding the "fork tailed devil" thing, Grau Geist said LW pilots called the P-38 the Lightning. Was that the English "Lighting" or German "Blitz"?

 

[GrauGeist]

The P-38's nickname was picked up and used for propaganda purposes.
Authors writing later, took that "legend" and embellished on it - from there, the "legend" took on a life of it's own.

 

[SaparotRob]

The P-38's nickname was picked up and used for propaganda purposes.
Authors writing later, took that "legend" and embellished on it - from there, the "legend" took on a life of it's own.

No, that I got. The LW pilots called it the Lightning. Did they say "Gerhardt, was that fokker flying a Lightning?" or "Jah, that Fokker was flying a Blitz?"

 

[DerAdlerIstGelandet]

 

[GrauGeist]

Probably along the lines of: "Gerd, that Schfanz nearly shot me down!"

(The expletive can apply to Lightning, Mustang, Spitfire or other type)

 

[DerAdlerIstGelandet]

Probably along the lines of: "Gerd, that Schnearly shot me down!"

(The expletive can apply to Lightning, Mustang, Spitfire or other type)

Fixed for accuracy.

 

[gruad]

Nope no mein nada no. All RR Merlin V1650 and Packard Merlin engines were built to the same very exact tolerance. Rolls Royce despite the myth did not build Merlins by carving it out of a block of aluminium.

This myth has been busted so many times I think it's time it should be burnt at the stake.

Point taken. The story is wrong and so was I on further investigation.

Packard churned out loads of engines but the RR conglomerate turned out more and they can only have done this by using the same modern manufacturing techniques.

It's really undermining a great British success story.

 

[pbehn]

Point taken. The story is wrong and so was I on further investigation.

Packard churned out loads of engines but the RR conglomerate turned out more and they can only have done this by using the same modern manufacturing techniques.

It's really undermining a great British success story.

The story results in looking backwards at history. The Merlin first ran in in 1933, it was just another engine, no more or less special than a Kestrel Peregrine Buzzard and Goshawk. Most engines of the time had a run of a few thousand IF they were lucky, Packard demanded a minimum run of 5,000 to become involved, that is more than were produced for the Kestrel Peregrine Goshawk and most others. The suggestion is that RR were remiss in not designing the Merlin to be mass produced, well who forseaw a war being declared in 1939 prior to 1933? Who foresaw all the alternatives to the Merlin failing in one way or another leaving it the only choice or best choice for planes that were designed up to seven years after it first ran. Much hinges on a single quote by Lovesey about tolerances but Lovesey was speaking to someone from Ford not Packard and RR were in discussion with Ford not only in UK and USA but also France from very early days. Lovesey was involved with the Schneider "R" engines, there were 19 produced, although it was developed from the Buzzard I really dont know how a company produced 19 engines over several years, it is hobbyist production levels.

 

[ssnider]

"The suggestion is that RR were remiss in not designing the Merlin to be mass produced, well who forseaw a war being declared in 1939 prior to 1933? Who foresaw all the alternatives to the Merlin"​

​

That's exactly right The Merlin was designed for station or Carousel mass production, not method used by Packard. The choice of method depends the economics of volume of production, Continuous line requires high volume to be advantageous, thus the required minimum number of engines, The method also requires closer part tolerances then are needed for station or Carousel methods. That however says nothing about the tolerances used by RR and the final engine tolerance have to be very close to work properly.​

This web site may (or may not) have info on Packard tolerances but costs money" Packard Merlin V-1650 - Blueprints, Drawings & Documents | AirCorps Library

Attached is what English writer Ian Lioyd in Rolls Royce: The Merlin at war had to say about missing tolerances

 

[pbehn]

"The suggestion is that RR were remiss in not designing the Merlin to be mass produced, well who forseaw a war being declared in 1939 prior to 1933? Who foresaw all the alternatives to the Merlin"​

​

That's exactly right The Merlin was designed for station or Carousel mass production, not method used by Packard. The choice of method depends the economics of volume of production, Continuous line requires high volume to be advantageous, thus the required minimum number of engines, The method also requires closer part tolerances then are needed for station or Carousel methods. That however says nothing about the tolerances used by RR and the final engine tolerance have to be very close to work properly.​

This web site may (or may not) have info on Packard tolerances but costs money" Packard Merlin V-1650 - Blueprints, Drawings & Documents | AirCorps Library

Attached is what English writer Ian Lioyd in Rolls Royce: The Merlin at war had to say about missing tolerances

Actually, I just want someone to explain why Packard, Ford and Allison didnt have a better engine shooting off a dozen lines in 1939. An obvious question that needs an answer, like why did some Liberty ships break in two?

 

[TheMadPenguin]

Actually, I just want someone to explain why Packard, Ford and Allison didnt have a better engine shooting off a dozen lines in 1939.

Government and Money. Nasty combination.

An obvious question that needs an answer, like why did some Liberty ships break in two?

"critical temperature" below which steel loses its flex ability and thus under stress snaps.
Different steel formulas have different "critical temperature" points.
Also, square hatches on ship decks become focal points for stress. The cracking that in a few cases resulted in failure of the whole steel structure started there.
Also, welding methods involve local extreme temperature melting the metal together, and the cooling down afterwards results in steel with different flex/stress behavior.
Much better write-ups are available.
We cured the problem with rounding the hatch corners, and welding differently.

 

[Andrew Arthy]

Regarding the "fork tailed devil" thing, Grau Geist said LW pilots called the P-38 the Lightning. Was that the English "Lighting" or German "Blitz"?

Here's an extract from a Luftwaffe report from 20 November 1942, which was the first time the Germans reported the P-38 in North Africa.



Cheers,
Andrew A.

 

[swampyankee]

Government and Money. Nasty combination.

"critical temperature" below which steel loses its flex ability and thus under stress snaps.
Different steel formulas have different "critical temperature" points.
Also, square hatches on ship decks become focal points for stress. The cracking that in a few cases resulted in failure of the whole steel structure started there.
Also, welding methods involve local extreme temperature melting the metal together, and the cooling down afterwards results in steel with different flex/stress behavior.
Much better write-ups are available.
We cured the problem with rounding the hatch corners, and welding differently.

A number of the ships with the steels with a high NDT (nil ductility temperature) were kept in service, but restricted to warmer waters. One of the results of this problem was the development of fracture mechanics.

 

[swampyankee]

Actually, I just want someone to explain why Packard, Ford and Allison didnt have a better engine shooting off a dozen lines in 1939. An obvious question that needs an answer, like why did some Liberty ships break in two?

To whom would they be selling these aircraft engines? The government wasn't buying that many aircraft, and the commercial market was fulfilled by Pratt & Whitney Aircraft, Curtiss-Wright, Lycoming, Continental, Jacobs, Kinner, etc.