ron@wjvax.UUCP (Ron Christian) (08/07/84)
I was under the impression that it was possible to configure a blower so you could turn it on and off electrically from inside. A mechanical engineer frend of mine who is into that sort of thing says it only happens in movies. Does anyone out there have any hard data, pro or con? -- "Trivia is important." Ron Christian Watkins-Johnson Co. San Jose, Calif. (...ios!wjvax!ron)
rs55611@ihuxk.UUCP (Robert E. Schleicher) (08/09/84)
In regard to electrically switchable blowers only being seen in movies,
I can at least vouch for that part! In The Road Warrior (and maybe
in Mad Max, too), Mel Gibson's car has an interior switch that turned on his
blower unit. This appeared to be a GMC unit, and looked realistic enough,
but who can say for sure.
I do know, however, that old supercharged Mercedes, like the SSKs,
500Ks, 540Ks, etc. of the late 20s through late 30s had switchable blowers.
These cars had dual horsepower ratings, with and without the supercharger
in operation. Owners were also advised not to run with the blower engaged
for long periods, as engine reliability suffered somewhat. I also
think (but am less sure) that old blower Bentleys had such a switch
(actually, probably some form of mechanical linkage, without
a solenoid.
PS How about the nitrous oxide system the bad guy ("the Humungous")
had on his dune racer in The Road Warrior? Just the thing for
occasional massive doses of power.
Bob Schleicher
ihuxk!rs55611
AT&T Bell Laboratories, Naperville, Illhrs@houxb.UUCP (H.SILBIGER) (08/09/84)
I notice that the terms "blower" and "supercharger" are being used interchangeably. These used to have different meanings, to wit: a supercharger used a centrifugal turbine, and a blower used a two-lobe pump. All current passenger car superchargers are of the centrifugal type. The turbo refers to the driving mechanisn, which is a exhaust air driven turbine. The blower was usually driven mechanically from the engine, and was usually a Roots blower. At present the familiar 2 cycle GM diesels used in buses and large trucks still use a Roots type blower. Herman Silbiger
dmmartindale@watcgl.UUCP (Dave Martindale) (08/10/84)
I'm pretty sure that the "switchable" supercharger on the car in "Mad Max" was a fake. There is a scene where it shows Max flipping a switch in the car. It then cuts to a scene where the supercharger is seen to start up - in such a way that it is clear that the engine is starting at the same time. It turns over slowly for a bit, then suddenly speeds up. If the engine was actually running quite rapidly already (and the car was supposed to be driving on the highway at the time) and a clutch was engaged to start the supercharger, you'd see it come up to speed quite rapidly. To clarify: the supercharger may have been real, but it almost certainly was just driven directly from the engine, not through a clutch.
gmp@hjuxa.UUCP (PLEWA) (08/10/84)
<munch munch munch>
One thing that bothered me in the "Road Warrior" sequence,
the blower appeared to be of the "two lobe" variety. This is a
positive displacement device having little leakage past the rotors.
If this was the case, how did the engine get any air at all when
the blower was not turning???!!!
Film makers version of poetic licence I guess :-)emma@uw-june (Joe Pfeiffer) (08/16/84)
All you need to switch a supercharger on and off from inside the car is a magnetic clutch between the drive pulley and the blower. That shouldn't be too hard to arrange...