Airbus E-Fan - anyone made an rc copy?

[CappyAmeric]

Marzipan
1 hour? No problem. This can fly power on for a theoretical 5 although 2 hours non stop is the longest I have even done!
View attachment 208783
I agree with LitterBug entirely about conventional model EDFs. They are designed to give the maximum possible thrust for a given fan diameter rather than the best thrust to Watt performance which is exactly the feature required for a quad.
Note the Airbus E-fan actually uses what is in effect a multibladed prop in a short duct rather than a fully buried fan emulating a turbojet installation.
The latest turbo fan airliners with their huge fans are actually closer to a ducted prop than a conventional EDF so using a quad motor and even a 4 blade prop in a duct can fit inside a scale turbofan nacelle.
A 3x3.5 (76 mm) 4 blade inside a scale airliner duct powered by a 2205 drone motor. View attachment 208784
The duct, motor mount and pylon are 3D printed with the nacelle exterior in Depron.
View attachment 208785
Of course it only gives a fraction of the thrust of a true 76 mm EDF but it only weighs a fraction and only uses a fraction of the Watts. Its thrust/Watt is over twice that of the EDF.
It just so happens this is a scale nacelle for a RR Trent as used in the Airbus A350 so it just has to be built light enough to be able to fly on the limited thrust.
View attachment 208786
Everything sacrificed for minimum weight so its hand launched and belly land, carefully!
It weighs 652g with a 1000mAh 4s (try running two 76 mm EDFs on that!) with a combined thrust of close to 500 g.
A lot of effort and it is about as delicate as the full size but it does fly more to scale than most EDFs.
https://www.youtube.com/watch?v=b8ZGijxUhL

Beautiful! I have a type rating on the real A350. I wonder if it flies the same (.87 Mach, FL410, 15+ hours) 😝

 

[Marzipan]

It's high alpha i think
https://en.wikipedia.org/wiki/Angle_of_attack#Very_high_alpha

I could see this high alpha for the J-20 since it's a fighter...but the Blackbird was reconnaissance spy plane designed to go as fast as possible in a straight line. I guess it was given high alpha so it was easier to fly.

 

[Taildragger]

I could see this high alpha for the J-20 since it's a fighter...but the Blackbird was reconnaissance spy plane designed to go as fast as possible in a straight line. I guess it was given high alpha so it was easier to fly.

High alpha is a flight condition that nearly all planes can sustain. It is just a way to fly slowly while maintaining altitude.

 

[L Edge]

I could see this high alpha for the J-20 since it's a fighter...but the Blackbird was reconnaissance spy plane designed to go as fast as possible in a straight line. I guess it was given high alpha so it was easier to fly.

To design the SR-71 with 2EDF's presented many problems. One is, go negative with the nose and it guaranteed a crash at low speeds. At high speeds, nose up caused flips. Yaw was another area I had to resolve. If you review, very few models have been made using EDF's that go the range of taking off, flying around and doing a normal landing. Most guys put (prop)s on it and got it to work.


For the J-20, I was doing slow flying(high alpha) to see effects in wind. I solved the fast flying by adjusting the TV. I learned all the tricks by building and exploring.

Here is a transport I designed with 2 64EDF's that needed proper placement of the battery in order for it to have a good flight envelope. The fun part for me is to explore what is available to get it to work.