Living room free flight, rubber powered DIY airplane model tutorial using supermarket materials by Livingroom Flight
This tutorial is made for people to make them interested in the free flight rubber airplanes world. There is plenty of material online about household items aircrafts, a lot of tutorials available, but not too many are showing good flying video. See the performance of that bamboo skewers airplane in the video underneath. We will not use balsa wood for building the airplane, since the point of this tutorial is to build good flying airplane using everyday house items. We will use bamboo grill sticks which can be bought in every supermarket, yoghurt cup for the propeller blades, metal pins or guitar strings, since these can be easily bought in every music store. Normal metal pins will also work very good, or even paperclips. We will also need plastic thin foil from the grocery or sandwich bag or tissue for the coverings. Aluminium will be taken from the normal drinking can top part. We will make the bearing out of it. The airplane flies really well, check the video, I got 1 minute 15 seconds record flight in my supper small appartment. The balsa version (0.45g) is doing waaay more, but thats not the part of this document. The airplane presented in this turorial should come out about 1 - 1.2g weight
Small size area flight demonstration video
Collecting materials and tools
list of materials
bamboo skewers, empty drinking can, yoghutr container (about 2.5 - 3" diameter), metal pins for the shafts and hooks (or: steel guitar string works the best, you can get it super cheap from any music shop ~ 0.3 - 0.4 mm), thin foil (sandwich bags, microwave film) or thin tissue, usual cotton thread, plastic card or other hard plastic (e.g coca-cola bottle plastic red caps) to cut the washer from, model rubber bands (preferably TAN Super Sport Rubber) for the motor.
list of tools:
I will not name the tools here, please look at the pictures with the tools I am using.
CA (or other instant glue, Pattex CA liquid works great), wood glue, glue you can stick the plastic bag to the bamboo wood (in the Netherlands we have bison kit, please google it out for finding out counterparts.) If you plan to use paper covering 50/50 water/white-wood glue will be ok.
Choosing an airplane to build
Start with selecting the plan of the model you would like to make. Its a plenty internet sources with the good plans available. Choose the smaller airplane, so it can fly well in the small space.
I gave google a try and I choose the first model from the list. Its Rob Romash record holder ministick, the wingspan of those airplanes is 7" max.
You can download the plan here.
Preparing wood sizes
Take a close look on the plan now. The two big main rectangles are the wing and the tail viewed from the top. The long lines are the edges (leading and trailing), the short ones are the ribs. On the bottom we see the airplane viewed from the side. We will need following wooden components:
- leading and trailing edges
- 5 arch-curved ribs
- 2 winglets
- leading and trailing edges
- 5 arch-curved ribs
- 2 winglets
- motor stick
- tail boom
- 2 wing posts
All this parts have diferent sizes of wood. Please take a look on the picture how to split bamboo with the kitchen knife. Care must be taken not to cut yourself! Prepare woods for the leading and trailing edges for the wings and stabs, same size for the ribs (about 4 - 6 very thin sticks splitted from one skewer.) these should be I guess about 0.5x0.5mm and pretty strong. Diferent skewers can vary seriously in weight and stiffness, prepare more wood and extract the lightest and strongest pieces. Than prepare thicker wood pieces for the motor stick and for the tail boom (see picture). This is dificult step, you need to learn how to deal with bamboo and 'feel it'. The grill sticks are very cheap, so dont be affraid to throw the bad stuff away. Every wood piece which is not correctly chosen (too heavy or two weak) can drastically decrease the airplane performance.
After cutting the wood to proper sizes, let us prepare the ribs. To do that, we join the extracted wood for the ribs into the one long piece of bamboo. We do that by glueing the endings of the slim sticks together and secure it with the thread/CA. Look at the picture. Next, we need to soak that thing in the water like shown on the photo. Let it stay there for about an hour or so. In the meantime, we can proceed with the other work.
Preparing the metal parts (the bearing, propeller shaft, rear hook)
cut the top of the aluminium can out and make a hole somewhere on it with the pin or drill it if you have tools for that.
bend the hook from the guitar string or the metal pin like shown on the pictures. Make sure, shaft goes through the bearing hole easily. The rearhook is used for hooking up the motor to the frame. Make it from the same wire. The whole frame is shown in the next step. Check it if you have doubts about current step.
Putting the frame together
On the photo bearing is attached to the motor stick using the wooden spacer. That gives more space between the motorstick and prop shaft for the rubber knots which will form after winding the rubber. CA the bearing to the spacer and than the spacer to the motorstick. You can secure it with the thread also, though that should not be needed. Next glue the rear hook to the motor and finally the tailboom. You probably would like to secure this one with the thread. Check yourself if its needed. Always try to use as little glue as possible!
The whole thing can be viewed on the photos.
First thing you want to do is preparing the propeller blade template. Put the outline of the blade on the cardboard/carton etc and cut it out. Next draw two lines on the yoghurt bucket like presented on the photo. This lines are about 15-20deg slant. Apply the blades shapes on that lines and cut them out. I had to apply the blades shapes with a computer program to the photo, because I forgot to take this step's photo :) You will get the idea I hope. After cutting them out sand them to the thinnest you can get, still being stiff.
Next make the hole in the prop spar in the center of it and taper the thing from both sides. Prepare washer from plastic card or the soda plastic cup, e.g. coca-cola. slide the washer on the shaft and than add the spar. Make 90deg bent on the top and glue that piece of metal wire to the prop spar. Next glue the blades on the spar about 45deg. You can use pitch gage for that. Google it out if you want to use it. I used just the eyeball. Use CA to attach blades to the spar - see photos. Once propeller is ready, you can mount, add the rubber, wind it about 300 times and see how it performs. If good, try more turns (e.g. 800) and see how long it spins. Should be about 1 minute with 800 times.
Preparing the ribs for the wings and tail.
The wood being soaked should be ready by now. Please take it out of the water, and wrap around the jar like shown on the picture. Secure it with the cord / tape etc and dry it out. I have used the oven for speeding things up. If you can not do that, just let it dry over close to the heating or leave it for few hours to dry by itself. Once its dry, you can remove it from the jar form. Next cut the correct lenghts out of those rounded sticks. Notice, that I already cut shorter ribs for the stablilzer. See photos.
Oh the cheese in the oven was just left there because of my laziness, will not help increasing ribs stiffness, it might increase their smell though ;-)
Creating the wing and stabilizer wooden frame.
Lay down the leading and trailing edges on the printed plan. I have drawn shapes myself, because my plan paper got wrinkled before. Attach the edges to the plan with the stick tape. Do that for the tail and the wing. Than use the white glue (or CA if you like, but I prefer white glue for the bamboo here) to attach the ribs to the edges. You might want to use pins for keeping the ribs verrically while glue is drying. When the glue is dry remove the tape and you have main frames for the wing/tail ready. If the leading edges and trailing were longer than expected, trim them now.
Next you need to prepare the winglets for the wing and tails. You need 2 of each. See picture. You break the bamboo wood a bit and form the shape. Than apply CA to make it stronger if you want (I didnt, bamboo is strong by itself, it will keep the form even if broken a bit).
Covering the wing and stabilizer
Use thin plastic foil. Squeeze it into the ball and make it flat again. Stick it on top of the box as shown on the image.
Cover main frame of the wing and tail with the glue and place on the film. See photo. Le the glue dry, and using the blade or scissors remove plastic excess.
Now we need to add dihedral. Break the trailing and leading edges of the wing and stab outside the internal two ribs to form dihedral like on the picture. Apply a bit of CA on the breaking places and let it dry.
Next, glue the winglets vertically like shown on the photo. Cover them with the film/paper tissue AFTER gluing.
By now we have all the components ready. We need to make that working together now.
Putting all together
Use CA for attaching stab to the tailboom.
Also prepare two wing posts and attach them to the frame like shown on the photo. Secure with thread, if needed. You might want to use paper tissue tubes for mounting wings. This will allow to remove the wing for transportation and add some trimming possibilities. Use two "L" shaped aluminium pieces to attach the wing to the posts. You can manipulate the "L" angle of the trailing edge to add wash-in (needed for the left turn). Wash-in prevents stalling on turn. Left trailing edge should be lower than the leading edge, than it means, that the left wing has wash-in, or its washed-in.
Attach the strand of model rubber, wind it and let if fly! :)
Have a good and long flights!