WIX Archives
Re: Merlins and Griffons - The clever bit....
Posted by PeterA on Mon Oct 28, 2002 01:41:11 PM
In reply top Re: Merlins and Griffons posted by Christer on Mon Oct 28, 2002 11:50:12 AM
The clever bit was the ability of Rolls Royce to continuosly develop the supecharging.
: Ron,
: I think that You?re spot on. I actually have one of the bo
: oks from RRHT "Rolls-Royce Piston Aero Engines". Quite det
: ailed for such a small book with such a huge topic. You ge
: t a good overview of pinpointed technical difficulties and
: development.
: The Griffon and the R have the same ancestor, the Buzzard
: (H-engine) which was a scaled up Kestrel.
: The Griffon was a derated R tested as early as 1933 but no
: t continued at that time. Shortly before the war it was ta
: ken off the shelf and experimental runs started in 1939 an
: d the first production variant flew in a Firefly in 1942.
:
: I have a feeling that the lower developement level of the
: Griffon focus on the RPM, 3,000 for the Merlin and 2,750 f
: or the Griffon, an illusory difference.
:
: What really is important is the maximum piston speed which
: dictates the load on the bearings, crankshaft, con-rods e
: tc.
: The stroke for the Merlin is 152 mm which at 3,000 rpm giv
: es 15,2 m/s.
: The stroke for the Griffon is 168 mm which at 2,750 rpm gi
: ves 15,4 m/s.
: If you add the higher component weights in the Griffon to
: the equation the difference is bigger than what is indicat
: ed by the piston speeds.
:
: I don?t believe that there was any significant difference
: regarding developement level, do You?
:
: Christer