Ducted fan aircraft

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Doggzilla

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Ya, I was just wondering where he went. Imagine he is up to something else while the economy is so slow. Last year almost half of my competitors went bankrupt. We were clearly in a recession and sales were horrendous.
 

Riggerrob

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Go review the Rohr 2-175 drawings available on the www.frasertechnologies.com website. Mr. Fraser is an engineer who worked on the Rohr 2-175 duct system. Rohr flew that prototype successfully because of their extensive experience designing and building engine cowlings for both radial and jet engines. For example, when they added the internal spinner, climb rate improved by 50 percent!
 

Doggzilla

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Go review the Rohr 2-175 drawings available on the www.frasertechnologies.com website. Mr. Fraser is an engineer who worked on the Rohr 2-175 duct system. Rohr flew that prototype successfully because of their extensive experience designing and building engine cowlings for both radial and jet engines. For example, when they added the internal spinner, climb rate improved by 50 percent!

Fascinating. I had theorized a spinner would help because the slow moving center of the fans allow pressure losses.
 

henryk

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Go review the Rohr 2-175 drawings available on the www.frasertechnologies.com website. Mr. Fraser is an engineer who worked on the Rohr 2-175 duct system. Rohr flew that prototype successfully because of their extensive experience designing and building engine cowlings for both radial and jet engines. For example, when they added the internal spinner, climb rate improved by 50 percent!
from=

"
Another photo of the 71-X and Cessna. Note the walls covered in canvas.
The walls were stacks of hay bales for deadening the sound during test
run-ups.

You could walk around the outside and
actually hear very little sound.
"

=moore explanation ? (hay bales ?)
 

Vigilant1

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"hay bales" are cubes of hay. The hay
(straw, grass, animal fodder) has been cut, dried, compressed together and tied into cubes. Apparently, the Rohr folks made walls of these, covered with fabric , to absorb the sound. Cheap, easy, apparently effective, and you can feed it to the cows when your program ends.
 

RonL

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Any comment on using the 'Trompe' arrangement, as a turbine inside a duct, as propulsion mean?
Blessings +
As I see it, this is a case of water being used with gravity to produce an end result of some amount of low pressure compressed air.
In an airplane, ram air as a result of speed can entrain larger amounts of lower pressure air volume, which might in turn power some form of low-speed Tesla Turbine inside a duct or tube portion of the fuselage.
I think this group is not too much inclined with this kind of thinking, but then there are a lot of newer members that seem to bring new things to the topics of discussion. ;)
 

BJC

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In an airplane, ram air as a result of speed can entrain larger amounts of lower pressure air volume, which might in turn power some form of low-speed Tesla Turbine inside a duct or tube portion of the fuselage.
I think this group is not too much inclined with this kind of thinking, but then there are a lot of newer members that seem to bring new things to the topics of discussion. ;)
Neither inclination nor age of members here have any relevance to the topic. Physics does. Do an energy balance on the scheme you mentioned to convince yourself of its potential, or lack there of.


BJC
 

RonL

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Neither inclination nor age of members here have any relevance to the topic. Physics does. Do an energy balance on the scheme you mentioned to convince yourself of its potential, or lack there of.


BJC
I have been slow to respond because I'm not sure how to run an energy balance program on a conceptual scheme.
I can put together basic sizes and power units, but then how to calculate flow dynamics, frictional push or drag values, heat exchanges, kinetic energy exchanges and or storage, plus a number of other variables, all exceed my level of education and engineering design ability..... (yet I have a working model in my mind).
 

Vigilant1

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I have been slow to respond because I'm not sure how to run an energy balance program on a conceptual scheme.
..... (yet I have a working model in my mind).
In your concept, what energy source is ultimately used to produce the ram air? Conceptually, does your Tesla turbine, etc come out ahead of using the original energy source more directly? Using (realstic) conversion efficiencies for each step of the process (from existing examples) may tell you what you need to know.
 
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Doggzilla

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This is already a thing. And yes, it’s useful.

In steam they use a similar concept for injectors, but in reverse. The gas accelerated fluid instead of the fluid accelerating the gas.

A gas/gas system in aircraft is called an augmentor nozzle. It’s a wide tube fitted over the exhaust of small turbines with a gap between them. This allows air to be pulled in and converts the small amount of fast air to a large amount of slower air, which provides more thrust but lower top speed.

A quick google shows major Aerospace companies have patented variants of the design for future aircraft, so it’s definitely accepted as sound science.
 
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