Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Avanti on July 27, 2010, 04:44:28 AM
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So I was wondering if there were any propeller aircraft that have a transmission? not including flying car
By this I mean and aircraft that has the ability to change gear to get more prop rmp?
Avanti
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Prop RPM is not normally limited by the transmission. The prop pitch control gives the same effect as transmission in the sense of allowing the engine to stay within a given, optimal, RPM band while varying the power output.
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A crucial part of a 'transmission' is often the prop-shaft, so I nominate the P-39. Must've constantly worried the pilot with that hunk of metal spinning down there 'tween his legs, oooo-er.
:cool:
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"Must've constantly worried the pilot with that hunk of metal spinning down there 'tween his legs, oooo-er."
Imagine a bullet that breaks the shaft loose and a 1000+ hp V12 rotating a handy "cockpit blender"...
"By this I mean and aircraft that has the ability to change gear to get more prop rmp?"
The efficiency of the propeller is reduced when the blade tips exceed the speed of sound so there is no sense in rotating the propeller faster. The blade can be made longer and larger to increase the effective area, or number of blades increased, but the limitation of blade speed remains.
-C+
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Most of the watercooled vee type engines in World War II aircraft, such as the Allison V-1710, had a reduction box that reduced the output RPM, the ratio is usually around 2:1. So, at a maximum engine RPM of 3000, the prop only turned about 1500. The larger the prop diameter, the lower the ratio had to be in order to keep the prop RPM down below the point where the tips of the props exceeded the speed of sound. It is also possible to cavitate a prop in air, just like you can in water, since air becomes a fluid with the same characteristics of water at a certain speed.
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no there are not.
the classic definition of a 'transmission', is not used in aircraft to change prop RPM...however that being said,
properlor rpm CAN be changed by varying the 'pitch' of the blades in relation to the oncoming air.
The only 'gear changing' that might be associated with fighter aircraft is in multispeed blower ratios.
going from 'lo blower' to 'hi blower' et al.
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Some planes (La's) had gear levers for the superchargers, although, they also had allot of other levers, they were not easy planes to fly, irl, you had to pull and move about 6 levers in that plane to accelerate rapidly ( taken from wiki then confirmed with "Dragons on Bird wings Vol.1" and "Allied Fighters 1939-1945" )