One of the most important components of a paramotor is its propeller. The propeller is responsible for generating thrust, which propels the paramotor forward. In this post we’ll look at the various aspects of paramotor propellers, including their design, materials, and performance. We’ll also find out whether the size and number of blades makes a difference to a paramotor’s performance.
If you’re searching for a new paramotor propeller, chances are you’ve seen 2, 3 and 4 blade options, you’ll also notice that you have a choice of different diameter propellers, different materials, and many different designs. If you know nothing about propellers, knowing which one to choose can be difficult, and when you’re spending $400 you want to be sure you get it right.
Let’s look at everything you need to consider when choosing your next paramotor propeller.
Paramotor Propeller Design & choices
The design of a propeller is critical to its performance. Propeller design involves a variety of factors, including the number of blades, the shape and size of the blades, and the pitch angle of the blades.
Pitch and diameter
The propeller blade is essentially a wing, and usually you can extract the most thrust if it’s operating very close to it’s stall point angle of attack. The actual angle of attack is dictated by the blade angle or pitch relative to the shaft it’s mounted on, the shaft RPM, and the paramotor’s speed through the air.
Propeller diameter and pitch are limited by the power of the engine and resistance of the air being moved. A propeller with more pitch and diameter will not give the paramotor more thrust unless it has the engine power to turn it.
Paramotor propeller diameter is also limited by the paramotor’s cage size and pilot’s arm span, with the maximum propeller size for paramotors usually being around 140 cm. Manufacturers use fixed pitch propellers, and when buying a propeller you’ll need to match it to your specific engine. You’ll have a choice of different diameters, and sometimes you’ll have a choice of different pitch angles.
When it comes to paramotor propeller sizes, a larger size generally equals more thrust provided your engine has sufficient power. I’ve bought smaller diameter propellers in the past, and I’ve always been disappointed in the thrust reduction and the impact on my paramotor’s climb rate.
If you already have heaps of thrust, and you think your engine may be a little too powerful for your weight, a smaller propeller may be a good way to lessen the thrust and make the power and torque more manageable for you.
The number of propeller blades used on paramotors can range from two to six, with two blades being the most common. More blades generally produce more thrust, but also increase weight and drag. Let’s look at the pros and cons of 2 and 3-blade paramotor propellers, as these are the most common options you’ll see.
2 blade VS 3 blade props
2 blade propellers
Paramotor propellers come in a variety of designs, each with its own set of advantages and disadvantages. The most common design you’ll see is the two-blade propeller, which is simple, lightweight, and usually the most affordable option.
In general, 2-blade propellers are slightly more efficient, but efficiency doesn’t propel your paramotor, thrust does. Thrust is needed to overcome drag and weight, helping the paramotor to climb.
Two-blade propellers have a lower profile than three-blade propellers, which can reduce drag and increase its speed. However, two-blade propellers have some disadvantages as well. They produce more noise than three-blade propellers, which should be considered in noise-sensitive areas or for early morning flyers.
They may also produce more vibrations than three-blade propellers, which can be uncomfortable for pilots, especially those who enjoy longer flights. Two-blade propellers also produce less thrust than three-blade propellers, which can limit the weight and size of the pilot, and equipment that can be carried.
2-blade paramotor propeller pros
- Simple and lightweight
- More affordable.
- More efficient.
- Faster throttle response.
- Less blades to store and transport.
- Less to repair if it breaks.
2-blade paramotor propeller cons
- Louder than 3 blades.
- Less thrust.
- More vibrations.
- Less comfort in-flight.
Three-blade propellers are less common on paramotors, but they have some advantages over two-blade propellers. They aren’t as efficient, but they generally produce more thrust than two-blade propellers. They may also cause less vibrations, which can provide a smoother and more comfortable ride for pilots.
The size and power of the engine should also be taken into consideration. A larger engine will deliver a lot of power to the propeller, and to make the most of this power you’ll want a larger prop, or more blades. Due to the size limitations of a paramotor, a larger prop isn’t always possible, so adding a blade will be the best option.
Three-blade propellers also have some disadvantages. They are typically heavier and more expensive than two-blade propellers, which can increase the weight and cost of the paramotor, but they do produce less noise than two-blade propellers, and may be more desirable in noise-sensitive areas.
The choice between a two-blade and three-blade propeller for a paramotor will depend on the specific needs and preferences of the pilot. Two-blade propellers are lightweight and less expensive, but produce more noise, more vibrations and less thrust. Three-blade propellers create less noise, produce more thrust and less vibrations, but are heavier and generally more expensive.
Compared to a two-blade propeller, a slightly smaller three-blade propeller can produce more thrust at a given RPM, thus improving climb performance. Because of the smaller diameter, the propeller tips actually travel slower than the equivalent two-bladed design, which reduces noise.
If you’re a shorter pilot and need more ground clearance, a slightly smaller 3 blade propeller may be a good option.
A good example of this would be the now discontinued Parajet compact, which had a much smaller loop cage, housing a smaller 98 CM 3 blade propeller as seen below. Even with such a small propeller, the compact was still able to produce 55 KG of static thrust from a 180cc engine!
3-blade paramotor propeller pros
- More thrust.
- Less noise.
- Less vibrations.
- More comfort in-flight.
- Option of more ground clearance.
3-blade paramotor propeller cons
- More expensive.
- Less efficient.
- Harder repairs.
- More weight.
- More items to store and transport.
Ultimately, the choice of how many propeller blades you need will depend on factors such as the weight and size of the pilot and equipment, the engine size and power, the desired performance, type of flying, and the noise sensitivity of the areas you fly over.
Which paramotor propeller material is best?
Carbon composite VS wood propellers
Carbon composite propellers are made from a combination of carbon fiber and resin, which results in a lightweight and strong material. This strength allows the propeller to withstand the high rotational speeds and stress of the paramotor’s engine, while the lightweight construction allows for greater efficiency and performance.
E-props are a good example of true carbon composite propellers, but be wary of buying from other manufacturers as many of them produce propellers with just a thin carbon coating for aesthetics, but the composition is actually closer to a much weaker and more fragile glass fibre composite.
A carbon composite propeller will generally give a faster throttle response due to the lighter weight, this will be desirable for clutched engines, and smaller less powerful engines. They’ll also be much more rigid and durable than a wooden prop.
Carbon composite propellers are also more transportable and easier to store, this is due to them being supplied in either 2 or 3 pieces, depending on whether you chose a 2 or 3 bladed propeller.
Carbon composite sounds like a good choice so far, but there are some disadvantages. The cost will be much higher than a wooden propeller, usually around 50% more.
You also need to consider repairability if you happen to break one, which you will do eventually. A repair, and then rebalancing the prop afterwards will be much more difficult.
One plus is that if you only break one blade, you only need to replace one blade. If you can’t repair it you can just buy a single blade, rather than buying a full new propeller, but it may still need balancing depending on the manufacturer.
E-props claim that if you buy a single replacement blade from them it wont need balancing!!
Carbon composite propeller pros
- Durable and resistant to damage from debris or impact, which can be a significant advantage for pilots flying from rough or dusty terrain.
- Lightweight giving a better throttle response.
- Easy to store and transport to the field.
- Strong and less prone to damage while transporting.
- More rigid structure with less flexion under power.
- They look the part!
Carbon composite propeller cons
- More expensive than wooden propellers.
- Harder to repair and balance.
Wood propellers have been the traditional choice for paramotor pilots for many years, and they still offer some advantages over carbon composite propellers. For one, wood is a more affordable material, which can make it a more attractive option for pilots on a budget, or beginners who are more likely to break a prop.
Additionally, wooden propellers are easier to repair and maintain, as any damage can usually be easily fixed with some sanding and varnish. Small dents and chips can also be easily repaired with some baking soda mixed with super glue, and then sanded smooth once set. This can easily be done at the field for a quick repair.
Despite these advantages, there are also some drawbacks to using wood propellers. One of the main disadvantages is that they are heavier than carbon composite propellers, which can result in reduced performance and efficiency. Up against the cheaper fiberglass composite props, they will usually be similar weights.
Additionally, wooden propellers are more prone to damage from impact or debris, and may need to be replaced more frequently as a result. The leading edge of a wooden propeller will show signs of wear very quickly. Contact with bugs, dust and long grass during take-off will soon show, but this isn’t usually an issue with carbon composite propellers.
Pilots regularly flying from dusty fields and beaches will notice this more, and carbon composite propellers will be the preferred choice.
Moisture ingression is also a concern with wooden propellers. If you store your propeller somewhere damp, or if the propeller is exposed to a humid atmosphere it may soak up moisture which can cause an imbalance in the blades, which will initially be noticed with higher vibrations during flight. To prevent this, wooden propellers should always be stored horizontally on the paramotor, or taken off and stored horizontally in a dry place in the home, and never in damp sheds.
Wooden paramotor propeller pros
- Much cheaper than carbon composite.
- Easier to repair and balance.
- Small amounts of damage can be repaired at the field.
- Preferable to pilots who like a traditional look.
- May be a better option for beginners.
Wooden paramotor propeller cons
- Heavier than carbon composite
- More prone to damage from impact or debris.
- Less transportable and require more space to store.
- Need to be stored properly, and away from damp or moisture.
- Will flex much more under power.
We all break a prop now and then, and how the propeller breaks should be a consideration. When a wooden propeller breaks during an impact with the ground, it will often break in two and send a large sharp piece of wood hurtling huge distances. This is a concern if you fly close to others; say at fly-ins, meetups, or if you operate a training school where beginners regularly break propellers.
On the other hand, carbon propellers often break into smaller pieces, and don’t usually send broken pieces large distances from the impact zone. This may be safer if you often launch in close proximity to others, but remember that the broken piece will be very sharp and should be handled with care.
Which material to choose?
Ultimately, the choice between carbon composite and wooden propellers comes down to a few key factors. For pilots who value performance and efficiency above all else, carbon composite propellers may be the best choice. However, for those who prioritize affordability and ease of maintenance, wood propellers may be the better option.
Caring for your propeller
It’s best to remove your propeller from the paramotor for storage and transport, as you’ll be moving the paramotor around a lot, and it’s easy to catch the prop on things like door frames as you carry it through them.
Never grab the propeller to move the paramotor, exerting any force on the propeller will risk damaging the blades.
Get yourself some prop covers to prevent damage when you’re transporting your propeller, and never store the blades together in the same cover, as you don’t want them rubbing past each other and damaging their surfaces.
Keep wooden propellers horizontal and away from direct sunlight or heat sources, and away from moisture. You can use a wax on them to help reduce the chance of moisture being soaked into the wood, ask the manufacturer what wax they recommend.
Keep the propeller clean, especially along the leading edge. Use a gentle soap and warm water if you need to, but don’t keep wooden propellers wet for any more than a few seconds, and dry them immediately with kitchen tissue.
Always inspect your paramotor propeller pre-flight and check for any splits and chips, and check for warping etc.
When you bolt the propeller onto the paramotor before each flight, use a torque wrench so that you do not damage it or shear off the bolts by over tightening them.
Paramotor propeller round up
We’ve looked at the main things you need to consider when buying a paramotor propeller, but you’ll need to be careful when selecting a manufacturer. Your best bet is to stick with well known tried and tested propeller brands like Helix and E-props, these are high quality propellers that are well trusted by the paramotor community.
Now you know how to choose a propeller, check out these posts: