Airbus A321 scratch build
 

Hi guys,

a few years ago i started a scratch build of an Airbus A321. After being really enthusiastic with this project, i lost my motivation with a pc harddrive crash, where i lost all my CAD data.
The wing was nearly finished, but all my data concerning the wing construction and the aircraft nose was lost. Well, luckily, due to my job i have access to the manufacturers manuals.
And now i decided to finish this litte project. I'm curious if it flies.

And here are the specs.:


Span: 61"
Lenght: 76"
Weight (at least i hope): 5,7lb
Propulsion: 2x Wemotec MiniFan (5 blade classic) with HET 2W Motor on 3S lipo
Gear: E-Flite 15-25 Retracts


Every couple of days i will post a pic until i reach the current state of the build.
Let's start with the wing:

The airfoil is a SG6040 at the root going to a CLARK Y at the tip.

http://www.rcuniverse.com/forum/atta...mentid=2158850

Regards

Andi

Here we go:

Wing halves joined, part of the sheeting applied and also pylon and engine attachments completed.
The engine pylons and nacelles are attached by two screws in aluminum bushes. The ESCs are located in the wing leading edge (not installed yet). The pros and cons of this Installation: Short wiring from battery to ESC to motor. But poor cooling of ESC. I'm not going to cut cooling orifices into the wing. Looks aweful.

http://www.rcuniverse.com/forum/atta...mentid=2158989http://www.rcuniverse.com/forum/atta...mentid=2158990

Regards

Andi

Installation of main retracts

http://www.rcuniverse.com/forum/atta...mentid=2159234

Regards

And here the finshed wing.
All thats missing is the wing tip fence.

http://www.rcuniverse.com/forum/atta...mentid=2159541

Regards

Looks good!

Were you able to recover your original plans or are you working from tech order drawings? You have some skills!

Hi
No, all my original plans and drawings are lost since everything was done in CAD.
I have to repeat the complete CAD construction. For most parts i use original Airbus CAD drawings that can be downloaded from Airbus http://www.airbus.com/support/mainte...rbus-aircraft/
For special parts like frames in the cockpit and fwd fuselage area i have some drawings from the original frames.
And some parts i do on my own.

For example the engine nacelles.
My A321 Modell is equipped with "IAE V2533 Engines", that makes the nacelle construction a litte easier.
Here's how i do it:

First, i make drawings in CAD. For that i use a simple to use CAD Programm called "Darft Board Pocket". It's in 2D:
http://www.rcuniverse.com/forum/atta...mentid=2159722

Note that my nacelles are simplyfied. Different to mine, the real V2500 engine nacelle is not a perfect circle in shape. Actually its slightly oval a little bit thicker at the very bottom. But at a scale of 1:23 this is hardly visible. So why waste a lot of time and "brainpower" in creating something you cannot see? What is important with the nacelles is that the inlet has an angle of 6° when viewed from the side. This is an eyecatcher an much more important than the oval shape.


When finished, i order the parts from a milling service, and simply put everyhing together. Somthimes it feels like a kit.

http://www.rcuniverse.com/forum/atta...mentid=2159723http://www.rcuniverse.com/forum/atta...mentid=2159724

Regards


Andi

Nice!

Nice project!
Another A321 with IAE nacelles can be found here: http://rauch-airliner.com/A320E.htm

Hi

Yes you are right. I also know the Rauch Airliners. But they have two problems in common. Too big in size (for a 106" fuselage i would need a trailer) and too much wing loading.
My construction is more transport and trunk friendly and my wing loading is also less. I hope it flies.


Let's go to the fuselage:
The fuselage of the A320 Family aircraft is not circular shaped. It's a double bubble! Like most airliners.
The Diameter of the first upper bubble is 3950mm and the diameter of the lower one is 3852mm. Their centers are 240mm apart, which gives roughly an oval shape. In my models size fuselage height is 176,5mm width is 169mm.

I decided to build the fuse out of a foam construction that later will be covered by some glass plies to get a hard and smooth surface.

http://www.rcuniverse.com/forum/atta...mentid=2160760

Only for the nose gear and the later wing attachments there a plywood frames.

Here's the nose retract Installation including steering servo.

http://www.rcuniverse.com/forum/atta...mentid=2160761

The fuselage tail cost me some headache. After trashing the idea of building a classic plywood construction, i decided to use foam too. To get a roughly correct shape i cut the foam in sections by use of plywood Formers as guidance.


http://www.rcuniverse.com/forum/atta...mentid=2160762

The plywood Formers had been removed from the tail construction bevore glueing everything together.
The tail, of course, needs some sanding and shaping before finished..

http://www.rcuniverse.com/forum/atta...mentid=2160772

Regards

Andi

I like your construction methods - everything looks so clean and simple...

Hi

After application of some putty (i use the white very light filler from hobbylite) and some sanding, the fuselage tail looks much better now.


http://www.rcuniverse.com/forum/atta...mentid=2161770

Now ist time to install the wooden horizontal and vertical stabilizers.
Therefore i had to make some cutout. Looks much nastier as it really is.

http://www.rcuniverse.com/forum/atta...mentid=2161771
Before i can close this cutout again. I need to install the rudder Torsion link.
And before i can install the rudder torsion link, i have to get access into the fuselage. For Installation of the wings, i have to make a larger cutout, which also serves as Access to servos and Receiver.
And this cutout is covered by the bellyfairing.

To get erverything straight again:

1st: Build wing sattle and bellyfairing
2nd: Install servos for Elevator and rudder and install rudder Torsion linkage.
3rd: Close cutout for empenage on tailsection.

Ok, lets get started.

Today i made a rough cut of the bellyfairing.
The wing incidence is also included in it.

http://www.rcuniverse.com/forum/atta...mentid=2161773http://www.rcuniverse.com/forum/atta...mentid=2161774

Regards

Andi

Any more progress?

Andi - Any more pictures?

More pics are coming soon.
Just didn't find enough time to continue...

I made some Progress with the belly fairing.
After some sanding it Looks like this:

http://www.rcuniverse.com/forum/atta...mentid=2164445http://www.rcuniverse.com/forum/atta...mentid=2164446

Regards

Andi

Hi all,
yes i know it has been a while. Lack of time.

Unfortunately the engine nacells came out to be too heavy, making the whole plane extremely nose heavy. Since i had no idea how to change that (a tail installed battery is no option due to bad access) i decided to design new engine cowls. More lightweight ones. After some consideration i decided to build them much more closer to the real ones.

And thats what came out.
The upper one is the old heavy design. The lower one is the new one. The Fan unit is the same.
http://www.rcuniverse.com/forum/atta...mentid=2182512

This new nacelle is 50grams lighter than the old one. Saving 100grams on a 2600grams airplane is a lot.
http://www.rcuniverse.com/forum/atta...mentid=2182513

The sheeting is CAD design, too. The small one's for the inlet. The large on for the exterior.
http://www.rcuniverse.com/forum/atta...mentid=2182514

Inlet complete. Simply glued in.
http://www.rcuniverse.com/forum/atta...mentid=2182515


Best regards.

Time to build the most important part.
The Airliners nose.
You can build a perfect plane, but when its nose isn't correct, the complete plane Looks wrong somehow. Especially when we talk about airliners.
Here we go:
Cockpit Formers.
http://www.rcuniverse.com/forum/atta...mentid=2188574

Sheeted with Balsa and roughly formed Balsa radome.
http://www.rcuniverse.com/forum/atta...mentid=2188575

Sanded after some putty application.
http://www.rcuniverse.com/forum/atta...mentid=2188576http://www.rcuniverse.com/forum/atta...mentid=2188577http://www.rcuniverse.com/forum/atta...mentid=2188578


Best regards

Andi

Wonderful workmanship and attention to detail - enjoyed seeing how wing center section, nacelles, and nose construction challenges are addressed - thanks for documenting and sharing.

Hi all,

The first of the engines ist finished. Except covering of course. When looking at the pictures i start to wonder how to get the inlet covered.
Maybe it is interesting to notice that the fan unit is not removeable anymore. I can maybe with some luck change the motor. But im not sure about the fan rotor. The fan rotor diameter is 69mm. On the contrary the inlet diameter is only 64mm. The diffusor shape of the inlet (like on the original engine) is the cause for that.
That means, if the fan unit gets damaged, i need to build a complete new engine like seen on the pictures.

http://www.rcuniverse.com/forum/atta...mentid=2190047http://www.rcuniverse.com/forum/atta...mentid=2190048http://www.rcuniverse.com/forum/atta...mentid=2190049

Another detail concerning flight control. The Eagle Tree Guardian supports some flight envelope features like on the real Airbus A321. For example: duch roll damping with the rudder, turn coordination, bank angle and pitch angle protection and flight characteristics like on an advanced fly by wire airliner. Of course some adjustment flights might be necessary.
http://www.rcuniverse.com/forum/atta...mentid=2190050

As you see, i am not just trying to pattern the look, i also try to get as close to the real things flight characteristics as possible.


Best regards


Andi

Request for Info
 

You say you have access to Airbus (A321) Manuals. Do they quote wing root incidence angle, wing twist angles, show diagrams of airfoils used (or airfoil section designators), wing and horizontal tail dihedral angles, wing/tail/fin drawings, connection points in fuselage and wing of landing gear, ...? Are they online, and if so, what is their web address?

Any news ? :) Flying the real in Europe and only the A321 I am very interested to see the end, and to have some advice because I was planing do draw the same by myself.

hello,

great job, it is getting there and really nice!
I have myself one to build in the next couple of months, but it is from a semi kit and slightly bigger at about 2,71m (109") long and 2,13m (84" wingspan).

Looking forward for more progress on yours!

Hey , i bulding the tail of the airplane but there are some parameters i don´t have , could you help me with that data is for a reasearch proyect,

This looks amazing!

Any further progress on this model? would be such a shame to stop now.

I'm an Airbus 321 pilot and I must say you have the nose spot on!