Select your desired text size:

Professionally recreated, this is a real blueprint - made directly from a vellum master - Measuring a generous 42"x 30".

Rolls-Royce Merlin XX/ V-1650 Packard 28.

We have all three of the Merlin series Blueprints. This blueprint is the Rolls Royce Merlin XX/ V-1650 Packard 28, the second in the series. (Merlin XX/ V-1650 Packard 28: Single-stage, two-speed gearbox)

The Merlin was considered to be so important to the war effort that negotiations soon started to establish an alternative production line outside

← Acknowledgements and Bibliography

This engine was a ((single stage, two speed supercharger)). This engine (Merlin 28) was used for the Lancaster bomber. The USAAF version of this engine was designated the V-1650-1 which were used on the P-40F's.

The initial Packard modification on the Merlins were done on this engine by changing the main bearings from a copper lead alloy to a silver lead combination and featured indium plating. Indium plating had been developed by the General Motors (Pontiac Division) to prevent corrosion which was possible with lubricating oils that were used at that time. The bearing coating also improved break-in and load carrying ability of the surface. British engineering staff assigned to Packard were astonished at the suggestion but after tear down inspections on rigidly tested engines they were convinced the new design offered a decided improvement.

As the Merlin evolved so too did the supercharger; the latter fitting into three broad categories:
 

• Single-stage, single-speed gearbox: Merlin I to III, XII, 30, 40, and 50 series
• Single-stage, two-speed gearbox: Merlin X, Merlin XX 
• Two-stage, two-speed gearbox with intercooler: mainly Merlin 60, 70, and 80 series

Most of the Merlin's technical improvements resulted from more efficient superchargers and fuel with increased octane ratings.