Ducted fan aircraft

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Lendo

Well-Known Member
Vigilant1, "This little pusher" reminds me of a bigger twin Boom version of the new Zealand Snark. I actually like it.
George

Hephaestus

Well-Known Member
Isn't it the AHRLAC from South Africa?

Urquiola

Well-Known Member
THANKS,
I'm not sure about the meaning of your query, but can't provide more than suggesting looking in any search engine with the title of presentation above by Sepideh Jafarzadeh, or his name. Blessings +

Urquiola

Well-Known Member
About 'Fantrainer' the John Deere Wankel RCE research deserved a better fate. Images in SAE paper 890324.
About aviation engines, an Spanish specialist in Engine Maintenance and repair, Ricard Miguel Vidal, prepared an Encylopedia 'El motor de aviación de la A a la Z', available at Aeroteca, Barcelona, of open consultation for AEHS members www.enginehistory.org it's $15, or so, a year, membership fees. Blessings +View attachment 97483View attachment 97484 Urquiola Well-Known Member About 'Fantrainer' the John Deere Wankel RCE research deserved a better fate. Images in SAE paper 890324. About aviation engines, an Spanish specialist in Engine Maintenance and repair, Ricard Miguel Vidal, prepared an Encylopedia 'El motor de aviación de la A a la Z', available at Aeroteca, Barcelona, of open consultation for AEHS members www.enginehistory.org it's$15, or so, a year, membership fees.
Blessings +View attachment 97483View attachment 97484
These are John Deere Wankel Aircraft engines, images come from SAE paper 890324

piolenc

Member
May I modestly recommend the book that I wrote with George Wright, Ducted Fan Design, Vol. 1. You can find it on Amazon or on Lulu.

mm4440

Well-Known Member
Hi Marc, was there ever a vol. 2 published? Written?

Riggerrob

Well-Known Member
This book can be ordered here:
Would you count Archon as a "tunnel aircraft?"
How loose a fit before a duct becomes a tunnel?

Malish

Well-Known Member
Would you count Archon as a "tunnel aircraft?"
How loose a fit before a duct becomes a tunnel?
What do you mean?

Riggerrob

Well-Known Member
Would you count Archon as a "tunnel aircraft?"
How loose a fit before a duct becomes a tunnel?
Page 82 of that book mentions "tunnel aircraft." Without reading the entire textbook, I am not sure what the authors mean by "tunnel aircraft."
Perhaps by "tunnel" they mean a ducted fan with a long intake "tunnel" ala. PJ-11 Dreamer????????

Perhaps Archon and Custer Channel Wing should be referred to as "channel wings" or "canal wings." The two words mean almost the same thing in English, but "canal" is easier to understand. Most earth-bound canals are half-full of water (try to picture downtown Amsterdam). By "channel" or "canal" I mean an open-topped, rather crude ducted-fan.

Malish

Well-Known Member
Page 82 of that book mentions "tunnel aircraft." Without reading the entire textbook, I am not sure what the authors mean by "tunnel aircraft."
Perhaps by "tunnel" they mean a ducted fan with a long intake "tunnel" ala. PJ-11 Dreamer????????

Perhaps Archon and Custer Channel Wing should be referred to as "channel wings" or "canal wings." The two words mean almost the same thing in English, but "canal" is easier to understand. Most earth-bound canals are half-full of water (try to picture downtown Amsterdam). By "channel" or "canal" I mean an open-topped, rather crude ducted-fan.
I think right word for "tunnel" would be "canal" or "channel" - if we're talking about ducted fan aircraft. For me "tunnel" associates more with auto or rail road.
Only difference would be, how long or short this air "channel"(duct) is - that will effect DF performance. On our PJ-ii "Dreamer" we made the air channel/air duct as short as possible, but without "ruin" the look of aircraft.

raytol

Member
Page 82 of that book mentions "tunnel aircraft." Without reading the entire textbook, I am not sure what the authors mean by "tunnel aircraft."
Perhaps by "tunnel" they mean a ducted fan with a long intake "tunnel" ala. PJ-11 Dreamer????????

Perhaps Archon and Custer Channel Wing should be referred to as "channel wings" or "canal wings." The two words mean almost the same thing in English, but "canal" is easier to understand. Most earth-bound canals are half-full of water (try to picture downtown Amsterdam). By "channel" or "canal" I mean an open-topped, rather crude ducted-fan.
I took the "Tunnel aircraft" to mean aircraft that have long intake ducts before the propeller. The tunnel really cuts down the thrust from the fan!
I did a lot of duct design for my first flying car project. It had 2/3 of the fan as a ducted fan and the other 1/3 as a tunnel duct fan.
The REAL problem I see with ducted fans is being able to keep the tip clearances to almost nothing while the duct and structure around it is deflecting!
I solved this by putting a ring around the blade tips inside the duct which allowed me to use about 2 inches of clearance with an increase in thrust due to the extra mass of the air moving through the duct.

henryk

Well-Known Member
which allowed me to use about 2 inches of clearance with an increase in thrust due to the extra mass of the air moving through the duct.
=ejection effect ? ( =+ ?%)

PS=Yours opinion=

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nestofdragons

Well-Known Member
=ejection effect ? ( =+ ?%)

PS=Yours opinion=
That trench will generate turbulences. I guess that will make matters worse instead of being a help.

Malish

Well-Known Member
=ejection effect ? ( =+ ?%)

PS=Yours opinion=
We're again talking about things what is NOT really work with DF theory and design for light GA aircraft! All this things(ejection effect, CR fans, notched duct and grove fan tips) may(or may NOT) increase DF efficiency, but defiantly will complicate DF construction, dependability, weight and cost

Malish

Well-Known Member
The REAL problem I see with ducted fans is being able to keep the tip clearances to almost nothing while the duct and structure around it is deflecting!
I solved this by putting a ring around the blade tips inside the duct which allowed me to use about 2 inches of clearance with an increase in thrust due to the extra mass of the air moving through the duct.
Would you describe it in more details? I don't understand 2" clearance of what?

henryk

Well-Known Member
I solved this by putting a ring around the blade tips inside the duct which allowed me to use about 2 inches of clearance with an increase in thrust due to the extra mass of the air moving through the duct.
-iff I understand
this "extra mass of the air" is ejected between duct and blade tips ring ?

-what is a crossection of this ring, its wide ? (airfoil or thin band )/ CF or GF ?

nestofdragons

Well-Known Member
Just a CRAZY idea, but i had to propose it ... just out of curiosity.

WHAT IF ... duct and fan are 1 part. So, you let rotate the duct too. I guess it is not such a problem to do that. A central bearing at front and rear and a driving belt. No more blade tip clearance problems. But ... would it improve the performance?

Sorry guys, i am just thinking out loud. Crazy ideas might lead to new insights ... of to a big smile

henryk

Well-Known Member
WHAT IF ... duct and fan are 1 part.
=very promissing !

thanks centrifugal force duct can be much lighter as static is...

=fan blades can be drived via duct,no hub...

GENIAL !!!