I'd like to know the source of that because aircraft power is NEVER measured in watts. Volts, amps - 24 or 28V systems. A generator drives don't break because of loads, there's other mechanical issues there
There may have been other factors like th torsional load, any any rate the story is in "Vee's for Victory" on pages 122-123. I was in error though, The original model test for the British for the C-15 engine was done with a 500 watt (that is what the book says) generator while the British specified that the
plane should have generator of no less than 900 watts and the actual unit fitted was 1500 watts. Allison made quite a number of gear and coupling sets for refit and and also a different generator was used.
Again I'd like to know references for this as maintaining electrical load at engine idle was usually a before takeoff checlist item and was a reson for abort (I believe this is specifically in the B-25 and B-26 checklist - I'm on the road so I don't have access to my library)
It may be quite possible to maintain the desired load at idle if the generator/s are big enough to begin with. One of the big advantages of the alternator over the generator (at least in cars from about 1960) was that the alternator could maintain about 60% of output at idle speeds and it could hit 100% at a lower speed than a similar sized generator. I have no doubt there was a certain minimum power level that the generators had to put out as part of a pre-flight check.
The failure of Curtiss electric propellers were mainly due to bearing failure that did not allow the prop to feather and the prop would run away, had little to do with loss of electrical power.
This may be semantics. IF you got the plane back on the ground and fixed the generator or replace the battery the propeller would operate just fine, it wasn't broken or it didn't "fail" any more than the electric window not working on a car with a dead battery. Jump start the car or replace battery and the window is "fixed". The problem is NOT being able to control the propeller if the available electrical power is too low.
Generators and later alternators were then and now never included in aircraft weight and are actually considered an airframe part in some QEC installations
I think you meant engine weight and not aircraft weight but I have made plenty of mistakes in typing or wording myself. The point was that different generators could be fitted to the same engine to suit the different applications.
The extra generator the P-38 was due to entire electrical loss on the left engine, not the operating load. You lost the left engine, you lost electrical power. Common sense, not electrical load dictated that fix
Quite right, but the point was the rules, regulations and even common practice were changing quite rapidly in the late 30s and early part of WW II. what was an acceptable practice or even risk in 1939-40 would be considered dangerous or even fool hardy by 1945 let alone today. The changes in electrical needs and supplies in aircraft were happening faster than the operational experience was being acquired to form good policies and regulations. Loosing entire aircraft due to the savings (weight or cost) gained by not having a second generator (or a big enough first one on a single engine plane) seems stupid now but was fairly common then.