Are ducted fans more efficient? - Aviation Stack Exchange
2016年5月8日 · A ducted fan can be designed to produce more thrust at the same fan (and same diameter) than a propeller -- or it can be designed to produce the same thrust at lower power. However, it is not likely to be achieved with a very short duct like the one you have pictured. That is more of a shroud that merely protects people from the blade tips.
electric engine - What are the advantages and disadvantages of …
2014年12月1日 · I would be very skeptical of the increased thrust claim - both efficiency and thrust of the E-Fan ducted fans are lower than what a well-designed propeller can offer. The addition of the shroud only increases thrust when compared to the naked fan, but the fan is a poor replacement for a decent propeller at low speed.
helicopter - Do ducted fans have a future in forward flight aircraft ...
2019年10月23日 · However, when learning that these benefits don't translate over into horizontal flight due to the duct's induced drag and pitching moment, I'm wondering if we'll ever see ducted fans in future aircraft. I'm aware of the NASA ducted fan manned-aircraft project that failed in the 60's, but today I found out about AgustaWestland's Project Zero and ...
On a ducted propeller, how does duct length affect thrust?
2018年7月10日 · So if we are looking at an aircraft with a ducted propeller (or a high bypass turbofan engine), does it matter how long the duct is? As an extreme example, would having a duct that extends 100 feet behind the prop give any added thrust (let's ignore drag/weight effects of the 100 foot duct)?
What is the highest possible thrust generated by 15cm ducted fan?
2015年6月29日 · Twin ducted-fan backpack. The $150000 Martin Jetpack uses two ducted fans powered by a 2-litre two-stroke engine of 200hp (~150000 watts?). The fan diameter looks much larger than your 15cm. The width of the machine is given as over 2 meters so I'd estimate the fan diameter is close to 80 cm. The company website doesn't say how they calculated ...
How does altitude affect the TAS and thrust of an electric fan …
2020年9月23日 · For example, an electric driven ducted fan has a tip speed of Mach 0.85 and was set to maintain the same power output of say 50kw no matter the altitude. What would happen to the TAS, IAS, thrust and the shaft rpm of the motor as well as tip speed of the ducted fan as the altitude increases?
Are the military tilted-thrust aircraft in the film Avatar feasible?
2015年1月14日 · Ducted fan VTOL aircraft have been flown since at least the 1960s. A notable example was the Bell X-22, a quad-ducted fan experimental aircraft built for the US military. It has no relation to the later V-22 Osprey tiltrotor. Though successful, no military aircraft since have used that technology. The Bell X-22 looked like this:
Is Ducted fan or Propeller better to maximize forward speed of RC ...
2020年8月3日 · I'm designing an RC aircraft of which the final goal is a crazy top speed. I'll be 3D printing and sanding / finishing the air frame surfaces to reduce drag. In order to achieve maximum top speed, should I use open 5 inch diameter 3 blade props (the ones used in racing drones) with a large pitch and beefy motor, or two (60-80mm) ducted fan (EDF ...
Why don't drones use ducted fans? - Aviation Stack Exchange
2017年3月31日 · The efficiency of the ducted fan can be increased by the shape of the duct. If the airflow is compressed, i.e. the outer airflow section is thinner of the inner section, the fluid is compressed (more compression means more speed in the airflow) and that's what gives most of the trust in normal propellers even if not ducted, if you note in small propellers airplanes, …
How does a fan differ from a propeller? - Aviation Stack Exchange
2016年5月2日 · You may like the attached chart, from the booklet: 'Ducted Fans for Ultralight Aircraft', by R. W. Hovey. It shows the efficiency of different propulsion systems according to AirSpeed of a flying machine.