Talk:Ducted fan
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I removed the sentence which implied 'high-bypass ducted fans ... are optimized for high-speed flight.' Based on the actual use of turbofans in the US military aircraft, high-bypass turbofans are found in a handful of combat aircraft (A-10 Warthog being one of them, with a bypass ratio of ~ 8:1.) The supersonic fighters F14, F15, F16, F18, and Mig-29 all use low-bypass ( < 0.8:1) turbofans. High-bypass turbofans are more efficient (than pure jet-engines) at high subsonic velocities.
anonymous (68.122.56.147) - 07/10/2005
"An unshrouded propeller is limited since their tip speeds approach the sound barrier at lower rpms." Shouldn't it say higher RPMs? -(Simm 11:41, 28 April 2006 (UTC))
- I believe it should read 'lower rpms than an equivalent shrouded propeller'. ericg ✈ 16:36, 28 April 2006 (UTC)
Kinds of ducted fans
This article makes the assumption that the only ducted fan is an airplane propulsive device. Ducted fans are a very common high-efficiency cooling fan design. For instance, almost all PC cooling fans are a simple form of ducted fan.
Should there be a separate page on the more common use of 'ducted fan' to refer to these air movers, or should there just be a short bit added to the front of this article that would mention other uses of the term? Loren.wilton (talk) 02:56, 11 March 2008 (UTC)
Many fictional aircraft have used ducted fans, for example the GDI Orca VTOL, or the GIJOE Dragonhawk transport, or the RDA Gunships in avatar. So when people think of a ducted-fan they think of aircraft
Contradiction
"Ducted fans are favoured in VTOL aircraft such as the Lockheed Martin F-35 Lightning II, and other low-speed designs such as hovercraft for their higher thrust-to-weight ratio." "At low speeds, the presence of the duct may create more drag than extra thrust, and therefore its comparative advantage to an open prop is canceled."
Without qualification, these two statements would seem to contradict one another; suggesting that low speed use is both favorable and a disadvantage. —Preceding unsigned comment added by 74.131.162.68 (talk) 02:24, 18 December 2008 (UTC)