Propeller blade drawing template

To figure out the pitch you can use a prop calc. Determine a material for your propeller blades. All well-built wood propellers are better at handling the aircraft vibrations, [4] X Research source but you need to use a strong, light wood like maple or birch. A straight grain that is uniform will help with balancing the prop.

You can use extra pieces that you cut. The more layers you have the stronger your prop will be. Even if the layers are very thin. To safe time you can try to find a lumber supplier that makes laminated wood planks that will suit your purpose. Draw out a pattern for your propeller. Now that you have determined how you want your propeller to look, create a pattern using a thick cardboard or poster board. Create the propeller in actual size. Include the center hole and draw a separate model for the pitch.

Cut out the patterns. These will be used as guides for carving the prop. Part 2. Arrange the wooden planks. You will need pieces of wood of various lengths. The longest pieces of wood should be in the middle with the smallest pieces on the top. Measure each blade to make sure it is equal in length. A propeller must have as much balance as possible in each blade to operate as desired.

Each blade should be crafted to be uniform as the rest. Laminate the planks together. You will need to use a very strong glue, like Resorcinol, to create aircraft propellers.

It may seem easier to use one large piece of wood, but you will have a stronger material by gluing a number of smaller pieces tightly together. Clamp or tie the boards together for 24 hours. Use a vice and a table to keep pressure on the boards while the adhesive dries.

You may find that using several clamps at various parts of the board will do a better job of keeping out any air. Part 3. Place your pattern over the block of wood and trace the profile of the propeller.

Draw a line all the way around the shape of the blade. Mark the hole in the center. Keep the prop stable. You may want to use a vice to secure the propeller while you work. If you don't have one you can tie down one side of the propeller to the table while you work on the other end to keep it secure.

Drill the center hole. Mark the hole from you design cutout, then drill it with a one inch drill bit. The hole should be at close to the center of the wood, but doesn't need to be exact. Trim off the excess wood. Cut the wood around the shape of the propeller profile. Use as saw and cut as close to the lines that were traced on the wood as possible.

Mark the pitch angle across the edge of the wood. Use the blade angle that was determined from the prop calc and mark off the shape of the pitch on the wood. Mark the pitch angle on the edge of the block of wood that would make the tip of the propeller blade.

Then draw a line along the length of the blade to mark the twist of the blade. Repeat at the opposite end of the prop blade. Trim away everything that is outside the angle. Use a saw to cut off the bulk of the excess wood first. Then, use a chisel or belt sander to work the wood into the correct shape. You will now glue your templates onto thin sheets of metal, and then you tin snips to cut out the cross section.

You will need to file down the rough edges because the template needs to be dead on. Typically you will want about 10 stations, or 10 cross sections from blade root to tip. By marking the profile of the propeller looking down on the wood you can use a hand saw to cut out the profile of the propeller, this will save you time when you go to 'hog out material'.

Now this is the most time consuming part, you will use a chisle or draw knife, or any cutting tool to start widdling away wood material until you can start fitting on you templates to see where material needs to be taken out. Once you have hogged out most of the unwanted wood, you can now use the templets and hold them up to the correct stations along the blade to see where material needs to be removed. Be careful not to remove too much, you can't put it back once its gone.

The hardest part will be the root area, were the templates are hard to align. Marking the front and back of the propeller with a small notch will help align the templates. You can use sand paper to sand down and smooth out the contour. Be sure to start will rought paper 40 grit to grit, and work you want down to a nice grit or finer.

Then you will apply some water proof finish. If it is an outdoor propeller you will need to use a thick water proof varnish.

If your really ambitious, you can make a propeller duplicator, which can more or less duplicate anything, but right now its duplicting a propeller, so we call it a propeller duplicator. Question 11 months ago on Step 2. Question 1 year ago on Introduction. Answer 1 year ago.

Question 3 years ago. I'm just about done with a test prop for my ultralight and want to make sure I use the right finish. Hey man, just wanted to say I noticed it was designed for an air-boat and my train of thought says that if it's powerful enough to push a boat with 2 people over swamp and grass, it should be able to taxi and pull a plane into flight, right?

So would just like to know if it could work as a plane propeller. The plane will be a small single passenger aluminum plane linked below, it says balsa wood, but I'm gonna make it out of aluminum. Reply 6 years ago on Introduction.

Cburgess, Thanks for the questions. Also, thanks for good laugh. Pitch is the distance that a propeller travels forward in a single rotation, if it were threading through a solid material. It is very important that both, pitch and diameter, are properly calculated. Pitch to diameter ratios typically start around 0. And they can go up to around 2.

In normal ship design, the blade area is also the pushing surface that transfers all the forward thrust into the ship. So we need a large blade area. How large? This gets governed mostly by cavitation. Although blade efficiency also plays a part. A propeller with a smaller blade area must pack in more lift per area. Generally, when you convince a propeller blade to pack in more lift, the penalty is extra drag.

That leads to greater torque on the propeller and lower efficiency. We also favor larger blade areas to avoid problems with cavitation. This should be the first check when considering smaller blade areas. When we try to squeeze extra lift out of a propeller blade, we increase the pressure drop on the blade face. That quickly leads to cavitation. Designers need to balance this blade area against the strength of the propeller. A larger blade area creates larger stresses on the propeller blade.

These can easily break the blade. The designer needs to counter this with thicker blade sections, purely to maintain blade strength. Remember that the blade shape is also the key to generating lift. A super thick blade section will be less efficient.

The blade strength ultimately limits the size of the blade area. This careful balance between blade area, section shape, and blade strength are why most designer stick close to designs based on standard propeller series. And part of that standardization required three different ways to measure the blade area. We can not fit all the complexities of a twisting 3D shape like a propeller onto 2D paper.

So propeller designers created three different ways to represent the blade area. Projected area is the area of the blades, projected onto the plane of the propeller normal to the thrust vector. Sometimes we use projected area for a first measurement when considering cavitation. For the developed area, we take each blade section and untwist it to bring the section pitch to zero.

It makes the blade flat, but each section still has thickness and skew. This allows us to see the true shape of the blade and distribution of chord lengths at each blade section. This is one of the most commonly used views seen on propeller drawings. The expanded outline is not really an outline. It does not show the true geometric shape of the propeller.

It consists of several sections stacked up. At each section, the propeller pitch is removed and the section is stretched out so that the chord of each section is flat. This is not extremely practical.

But propeller designers can use this to show the stacked up section shapes, locating the position of each section on the expanded area diagram.

Blade skew primarily reduces vibrations and propeller noise. Blade skew smooths out that transition. Rather than the entire blade passing at once, we start with the small area at the root of the propeller. The area slowly increases as more of the blade passes the structure. This gradual change in blade area smooths out the pressure pulses of passing blades. This is because a raked propeller blade reduces the overall propeller efficiency. But on smaller boats with outboard engines, blade rake is very common.

The raked propeller blade helps to prevent ventilation of the propeller.