enginehistory.org

[jjuutinen]

Is there any in-print source for thorough description of the V-1650-19 with its Sundstrand infinitely variable blower gearing? Did RR itself contruct test engines with such a feature?

[gwhite]

Merlin V-1650-19
12.0/110.1 5.0 to 8.3 .479:1 +19-3/4 -Supercharger gear ratio variable between the limits given
(American built Merlin)
No production
Quote from R-R literature

[jwells]

U.S. patent No 2,485,503 granted to long serving Packard engineer, Herbert L. Misch appears to cover the design of the Sundstrand variable speed supercharger for the V 1650-19 engine.

The two impellers were put onto separate shafts and only the first-stage was capable of infinite variability via a large epicyclic gear as a primary drive and the usual, doughnut-shaped Fottinger coupling, fluid drive units providing extra drive. The second stage impeller was the normal Packard two-speed mechanical drive using Wright Aero-type epicyclic gears in the layshafts.

The extra complexity of the design was considerable. It would be great to read the report on the tests done on the two engines fitted with the device.

Jerry W.

[dbirch]

Despite Rolls-Royce interest in this idea, it never tried it out on one of its engines. One of the negative aspects was that you needed a larger oil cooler to dissipate the extra heat generated.

Dave Birch, RRHT

[gwhite]

Two-stage R-2800s used this system, i.e., the main (2nd) stage being a fixed speed and the auxiliary (1st) stage being variable speed via a fluid coupling. These included -8s (F4U-1), -10s (F6F Hellcat and early P-61), -32W (F4U-5) and -18W (F4U-4). The first stage “coasted” until the critical altitude was reached, typically 12 – 14,000 feet when the auxiliary stage was engaged offering a ceiling of over 30,000 feet. Two-stage 4360s used a similar system. This gave a very elegant solution to the varying requirement at varying altitudes. Down side being, as Dave pointed out, that more heat was rejected into the oil but only when the aux stage was in operation.