These pages describe the building of a semi-scale Airbus A320 radio-controlled model plane.
I designed and built this rc Airbus A320 in 2004. At this time electric ducted fans were expensive and did not offer the same level of performance as the ones that are available now (that’s why I used props on the first prototype). The same applies for lipos and rc equipment in general. If I was to build it again, I would probably make some changes, both to the design and the equipment I would use.
Still, the plane flies very well and you can build it as per the plans, or modify it to add retracts, flaps etc.
Note 1: This is not a beginner’s project.
The rc A320 plane requires good building and flying skills. If you are new to scratch building, it’s better to consider an easier build first, like the Depron rc Beaver DHC2 also presented on this site, and keep the Airbus as your next project.
Note 2: When I designed this rc model, I wanted to make the plans freely available for personal use. But since I posted the plans of this rc Airbus A320 on my homepage in 2004, they have been copied, reposted and distributed on many other sites. There are even scammers selling the original DXF and PDF files on Ebay. Others are selling laser cut parts sets. I am not affiliated with, and do not endorse any of these resellers.
You can download these plans here or from the page I maintain on aerofred.com.
I originally wrote this article in 2005. I have added a few notes and higher resolution photos.
RC model specs
Wingspan: 1510mm
Length:1358mm
Scale: ≈ 1/27
Weight: 1,8 to 2.5kg (for best performance stay under 2.5kg)
Airfoil: NACA4412
Wing area: 25dm2
Wing loading: 72 g/dm2 to 80 g/dm2
Motor: 2x64mm edf
or 2x70mm edf (recommended)
Batteries: 3 to 4S Lipo 2500 to 3000 mah
3D model of the plane
I’ve modeled the plane in 3D using Rhinoceros 3D. The 3D model was then used to design all the parts and output the CAD 2D construction drawing to build the plane.
The airframe is built in two halves, using 3mm depron foam for the ribs and balsa spars. The structure is then be sheeted with 1.5mm balsa.
Depron foam offers the following advantages:
It’s about 4 times lighter than balsa in the same thickness.
It’s cheaper than balsa.
But it is quite fragile, doesn’t have a lot of stress resistance (especially in compression) and it’s easy to mark and dent it.
Below are some views taken from the 3d model.
Building the fuselage
The fuselage is made of two halves sheeted with 1.5 mm balsa. Once completed the halves are glued together to form a complete fuselage.
This method is very effective to build strong and light airframes. It is also particularly adapted for rounded bodies like this A320 we’re about to build.
Building the fuselage using this method is not difficult, it just takes patience and a careful work to adjust the balsa strips that make the sheeting.
Don’t forget that you need to build two symmetrical parts! Like for the wings 😉
This photo shows the CNC milled depron half formers that will be used for the fuselage of the plane.
The side view is printed and taped to the table. You will need to print a left view and its symmetrical right view for the other half fuselage.
The fuse formers will be placed on top of it to build the skeleton that will compose the airframe.
Once the side drawing is taped to the building board we start by pinning the main spar to the board.
This will help to properly position each fuse former.
The main spar is made of 3mm hard balsa to improve the longitudinal strength of the plane.
The next step is to pin the spars that forms the outline of the fuselage and the first and last formers (made of 3mm balsa).
Aluminium corners are a cheap and effective way to guarantee that everything is positioned straight.
We can now place each former on the building rig, using a triangle to guarantee that they are properly aligned.
Note the 3mm balsa doublers at the center of the fuselage where the wing will sit.
1.5mm light balsa is used to sheet the airframe. 3mm depron also works to sheet the body of the plane, but it will be more fragile than balsa sheeting.
Parts of the fuselage that can be unrolled are sheeted with larger balsa plates. The bottom and the nose are sheeted using smaller balsa strips to follow the curvature of the fuselage. It’s basically the same technique used to built a boat hull.
The center section of the fuselage, where the wing will sit, is fully developable. The template is drawn on the construction drawings for easier and more accurate cutting.
A sharp razor blade or a hobby knife are perfect to cut the opening for the battery hatch on the lower side of the fuselage
Once the opening is cut to the right size, the battery floor is glued in place. 6x6mm hard balsa spars are added for better rigidity.
It is easy to add retracts to this plane although I have not detailed the installation of retracts on the plan. It is just a matter to build a wheel well to the right dimensions in the front section of the plane.
The first fuse halve is now complete and it is time to start with the other side of the fuselage.
Note that the back of the fuselage is not sheeted yet. This will be done after the stabilizer has been glued to the airframe.
Building the other halve is the same, except that there is no opening to cut for a hatch.
You should now have to symmetrical half fuselages. Check all the seams on each part to ensure that they will nicely fit when glued together. Dry fit the parts together before glueing them.
Close-up on the front section of the fuselage. The cockpit will be built later, once the two parts that constitute the fuselage have been glued together.
The two parts are now assembled together to form a complete fuselage. Note the small opening at the front for a non retractable nose wheel. If I was to build this plane again, I would definitely install retracts and functional gear hatches.
The nose of the plane is carved from a block of solid balsa. I used the same method for the tail and the fake APU exhaust.
Note: When I built the first version of this plane 3D printers did not exist. But today I would probably 3D print the nose and the tail of the plane, rather than sculpting a block of balsa.
The bare fuselage weighs 240g (8.46 oz). Which is quite light, considering it is 1m35 (53.15 in) long and is 15 cm in diameter.
Horizontal stabilizer and elevator
Horizontal stabilizer and elevator are built like a small wing, using supports placed on the plan.
The stabilizer has a NACA 0009 at its root that blends into a NACA 0012 at the tip.
Because of the small chord at the tip, a NACA 0012 airfoil provides sufficient thickness to build the stabilizer.
There is nothing really difficult here. All ribs with their supports are drawn on the plan.
Once complete, the stabilizer is also sheeted with 1mm balsa. Note the braces on the elevator, for additional rigidity.
Since the NACA 00XX airfoil series are symmetrical, the same building jig can be used for both left and right elevators.
Vertical fin and rudder
All the parts needed to build the tail are shown here.
Milling the slots for the ribs with the right diameter end mill guarantees perfect alignement, but this is not really needed.
The vertical tail is built with a true airfoil, as for the full scale aircraft. The balsa structure is sheeted with 1mm thickness balsa.
As the tail is built without supports, carefully align all the parts to avoid twisting the tail.
Before continuing our work, we can take a break to dry fit the parts to the fuselage and admire the progression of this build.
This bird is getting along nicely and already looks very promising!
A small plane tool is used to shape the leading and trailing edges of the tail.
Once complete, the tail is sheeted with 1mm light balsa. To save weight the vertical rudder is left as an open structure and will be covered with material (Oracover, Ultracote or other covering film) later.
Note the addition of braces to increase rigidity, while keeping the structure very light.
The wings
This beautiful bird still needs a pair of wing before she’s ready to take off.
The wings are built using the usual method with balsa ribs and spars.
CNC cutting the parts will again save a lot of extra work and guarantee perfectly clean cut parts.
The airfoil used is NACA4412. Although not adapted for an acrobatic airplane (not the intent here), the NACA4412 has a predictable behavior even with high wing loading. It works well with flaps and with 12% thickness it gives enough to install retracts and other rc equipment.
The plan does not detail the installation of flaps on this plane, but the modification is possible and relatively easy to do.
The same applies for retracts. When I designed this model, I wanted to keep things simple and light, but installing a set of retracts is a great addition to an airliner.
The root rib is positioned at 85° to obtain the right dihedral angle( 5°)
Because of the sweep, each slot has to be filed on the rib before glueing the spars.
The rib N3 that will support the engine nacelle is also glued at 85° to take into account the dihedral angle. By doing so the nacelle will be positioned in the right vertical position when the wing is assembled.
Note the 1.5mm balsa with the vertical wood grain for the webbing of the main spar
Detail of the aileron
The wing tip will be carved from a balsa block
Wingbox
The wingbox is the part at the center of the fuselage that joins the two wings together.
A building jig is used to align all the formers.
I used block of foam cut and sanded to shape to create the contours of the wingbox. Balsa blocks can also be used and will be more impact resistant than bare foam.
Two tubes made of rolled balsa are installed to guide the wing bolts inside the wingbox.
Test fitting left wing to the wingbox
Engines nacelles
Below are a few pictures illustrating the build of the dummy engines nacelles. This is mostly for reference, unless you want to power this plane with propellers, as I did with the first prototype.
There are also some photos showing a test to vacuum-form the nacelle covers with a former turned on a wood lathe. This is a working method to make the engine nacelles. The master former could also be used to build a mold and make the nacelles with glass-fiber cloth (this is the method used on my Avro-RJ85). But today, owning a 3D printer, I would rather make a CAD model and 3D print theses parts, as on the Tupolev 154 I am currently building.
Airframe assembly, finishing the plane
We have now built all the components of the airplane. There is still work to do. Like finishing the sheeting of the tail section, building the cockpit, installing the radio equipment, and of course doing all the finishing work with the livery of our choice.
There are many possible options for the covering material. The easiest and fastest is to use covering film Oracover, Monokote or similar. It is also possible to apply a thin layer of glass cloth, 25g/sqm is perfect for finishing work and then paint the airframe. This solution, if properly done, will give excellent result, but will likely weigh more than covering film.
Here, I wanted to experiment with an old school method, using japan paper, dope and paint. I found the result mitigated and not worth all the work involved (not mentioning the toxic fumes from nitrocellulose dope). If it was to be done again, I would probably go for Oracover and use a vinyl cutter for the logos, windows, doors and hatches.
Video of the maiden flight - December 2004
First flight of the Airbus A320, back in 2004. My old friend Jean-Pierre, a true master in model building, was there to check the plane, before take-off. Unfortunately the camera stopped recording before the end of the flight.
Downloads
Various pictures
To complete these article, a few photos of A320 models built from my plans.
If you have built an A320 using these plans, you are welcome to send a few pictures of your model, I will add them to the build gallery.
