This instructable will explain you how to build a water pressure powered airplane.
You can use this instructable as inspiration to create your own model or build this one...
Step 1: Building the Launcher
To launch this airplane a launcher is needed similar to the ones needed to launch water rockets
The launcher I used, is based on the clark cable tie release launcher.
You will need the following:
- bicycle tire valve
- 150 cm of PVC piping of diameter 22 mm
- Some straight connection pieces for the PVC piping
- Some bend connection pieces for the PVC piping
- PVC glue
- 2 component PolyUrethane (epoxy will work to)
- cable ties
- electrical tape
- O-ring (22.5 mm outer diameter)
- Pipe of diameter 17 mm (or inner piece of Labello stick)
- Piece of PVC piping inner diameter aprox 35 mm
- Following these youtube videos will get you a good base to start with.
- Now that you have the base, we will make the input in which we will pump the air.
- To do so we will cut the bicycle tire valve out of the tire.
- Afterwards we will mix some 2 component PolyUrethane and fix the valve in a piece of 22 mm PVC piping.
Congratulations, the first step towards your water pressured airplane is finished!
Step 2: Making the Launcher Base
Now that we have the launcher, we will build a base in which it can be fixed.
You will need the following:
- Some MDF board of atleast 10 mm
- 30 cm of aluminium L profile 30 x 30 mm
- 1 meter of aluminium L profile 10 x 10 mm
- Some screws and bolts
- Saw a piece of MDF board, this will be the base of your launcher, the larger it is, the more stable your launcher base will be. But if you want your launcher base to be portable do not exagerate.
Aprox 30 x 45 cm is good.
- Saw two pieces of MDF board which will be the vertical parts of the base. The dimensions are shown in the sketch.
- drill a hole in the middle of the vertical pieces, this will be the pivot point of our launcher.
- Mill or saw a slot in the vertical pieces, a bolt in this slot will allow us to fix the launcher at a certain angle.
- Next fix the vertical piecces on the base plate using the 30x30 L profiles and some screws. The vertical pieces should have a 25 mm gap between them.
- attach the launcher guiding rails with some bolts to the launcher base, these rails should be parallel to the launch tube.
- Drilling multiple holes along the arc will allow maximum launch angle variation.
Step 3: Combining Launcher and Launcher Base
- To combine the launcher and the base simply put a bolt through the center hole of the base and through the hole drilled in the small PVC pipe which we made earlier.
- Fasten the bolt with nut.
- Put a bolt through the slot of the base in a way that the bolt is located under the launcher. Because of the weight of or airplane the launchtube will be pushed down, which will result in the pump tube wanting to move upwards. The bolt will stop this motion, fixing the launchtube at the launch angle.
Step 4: Airplane: Wing
Now we have a functional launcher fixed on a base we can start building the airplane.
we start by making the wing.
We will need the following
- a piece of Polyurethane insulation 80 x 80 cm
- using a saw the shape as shown in the sketch is sawn.
- Next we saw the wing in two halves if the polyurethane is too thick. The thickness of the wing should be 3 cm at its maximum thickness.
- Now we have our rough wing, we start shaping it using a rasp and some sanding paper. We want to achieve a profile like it is shown in the photos. Thing should be thin at the front , thicker in the middle and thing at the rear.
If the wing is shaped like this, it will generate 'Lift', which is needed for the plane to actualy fly.
if you are curious how a wing really works, you can watch this fun and easy to understand video:Click here
Step 5: Airplane: Body
To make the body of the airplane we need two water bottles.
and some PolyUrethane construction glue.
I have used bottles of the brand Bru, but any bottle with a straight of semi straight edges without embossing will work.
Because a video is much easier to understand than photos you can see here how the bottles are connected.
Because the bottles are made out of PET, they are extremely hard to glue. Do not use epoxy glue or simple arts and crafts glue because they will faill once pressurised.
Step 6: Airplane: Combining Wing and Body
Glue the body of the airplane to the wing on the centerline of the wing.
This is very important to achieve a balanced flight.
The tip of the wing should be at the middle of the body, to achieve a balanced airplane.
Using the PolyUrethane construction glue the body is fixed to the wing.
Step 7: Airplane: Tail
The tail is the next important component we will make.
To make this you will need modelmaking cardboard. This is a lightweight cardboard with a layer of foam in between.
Further you will need a lath of 10x10 mm and some PolyUrethane construction glue
- Cut the cardboard in shapes as shown in the sketches
- Glue the two pieces together
- Glue the lath the the wing on its center line. the lath should extend the wing for 50 cm. This is needed for a good flight, otherwise you will end up with a rocket instead of a plane.
- Glue the tailsection to the the end of the lath.
Step 8: Airplane: Make a Nosecone
As this was the case i have made a nose cone out of PolyUrethane isolation foam.
- Shape the nose using a rasp and some sanding paper, use your imagination for the shap
- To strengthen the PU foam, spray filler can be applied.
- The connection between the body and the nose is made out of paper tape sprayed with spray filler.
Step 9: Flying High in the Sky
Your airplane is now finished!!
You can paint your plane any color you like.
By putting paper tape on the wings and sprayed, straight lines are achieved.
You can now test your airplane
- Go to a large open field.
- Slide the body over the launch tube.
- Fix the colar over the cable ties.
- Start pumping
- Pull the colar off the cable ties
- Watch your airplane fly