There are a few companies out there trying to make one blade planform work on everything from a Rotax 277 to a Rotax 912 by trimming the diameter, varying the pitch, or adding blades. Their propellers may be efficient on some applications but cannot be efficient on all of them. Each type of application requires a specific design to maximize efficiency. POWERFIN has commissioned the services of professional aerodynamic engineers in order to produce a number of specific designs. For instance, a Powered Parachute requires a very specific design to maximize static thrust. The other flight configurations of climb and cruise are basically irrelevant for these types of vehicles. We have a propeller specifically designed for these types of vehicles, which produces 398 pounds of static thrust on a Rotax 582 with a 2.58 reduction ratio. That's about 50 pounds more than the other manufacturers have produced. There won't always be that much difference between the competition's propellers and ours but there is always some difference due to the professional engineering of specific, targeted designs.
The above paragraph highlights the reasons why it is necessary to have a specific design for your application. Even when that is done however, there is usually some imperfection to the design. In other words, if you were to order a fixed pitch wood prop and the person making it was the best in the business, the variables that must be accounted for are so numerous and uncontrollable that rarely can the propeller maker make a blade absolutely perfect for your application. This is especially true in the Ultralight/LSA category where small two-stroke engines can vary widely in horsepower and torque from engine to engine of the same make and model. The result of these variables is frequently a propeller that loads your engine slightly too much or too little and prevents you from throttling your engine's RPM exactly where you need, in order to use all available horsepower. With a fixed pitch prop you are stuck with what you have. With a fully adjustable pitch prop you can set the blades such that you load your engine to whatever RPM you choose. This also gives you the luxury of choosing whether you'd like to have better cruise or climb performance - something you can't do with a fixed pitch propeller. All POWERFIN propellers are fully pitch adjustable. [Back to Top]
Assembling the POWERFIN propeller and setting the pitch is no more difficult than putting the blades in the Hub's bottom half, placing the Hub's top half on, putting the hardware (bolts) in, selecting a proper feeler thickness (we give you a chart for a starting reference), and turning the blade solidly against the feelers. We call this our Speed Set (U.S. patent pending) Hub. The objective of our design was to eliminate ANY requirement of finesse or feel or ground leveling when setting the pitch. We did it and we can proudly boast that a ham-fisted-guy can do this in high winds with his eyes closed - and get it within a half of a degree on the first try! Another feature of the Hubs that simplifies the setup process is the fact that it takes only a single (Allen) wrench to do the job. There is no fumbling or fooling around with backing nuts in this design. One wrench and socket does the whole thing. The final feature worth noting about this innovative Hub is that you cannot set the pitch at all if the blades are backwards in the hub. This design precludes the possibility of many errors that could be committed in the course of assembling and mounting a propeller.
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See pictures of the assembly process here.
The new & innovative Apex series, fully ground adjustable Hubs are the finest crafted Hubs available to the Ultralight and LSA (Light Sport Aircraft) markets. Made in-house on our new Haas VF4 & VF2 CNC vertical milling station, these Hubs offer features that are unavailable on other hubs. By nature of the fact that we own the machine, we can take the time to pack features into our Hubs that we couldnít afford to buy from an outside vendor. They are highly sculpted solid 6061-T6 aluminum and are made to the finest CNC machining tolerances in the industry. In fact, we specifically designed the machining process to insure a perfectly balanced Propeller Hub. The Hubs can be anodized to a luxurious Gold or Black finish that you will be proud to display. It takes longer to make Apex Hubs, itís true, but currently no other hub rises to our Hub's quality - hence, we believe that the extra American craftsmanship is well worth it!
The multi-blade configurations (2, 3, 4 & 5 blade options) offered with our Apex Hubs allow us to take advantage of the large reduction ratios offered by Rotax and Hirth in their gearboxes. Also, more horsepower can be loaded into more blades so this may be a solution to some applications that have limited room to turn a propeller.
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See pictures of the Apex series hubs here.
The goal of those who design aerospace parts with carbon-fiber composite materials is to create a part that approximates metal in strength yet remains very light. In order to accomplish this the optimal fiber to resin ratio of the chosen fiber must be controlled so that the published mechanical properties of that fiber can be relied upon. If this ratio isnít controlled, the strength, weight, and consistency of the part will be suspect. High-tech aerospace companies normally use PRE-PREG composite materials to help them do this. PRE-PREG means that the fiber manufacturer lays the resin into the fiber mechanically. The fiber to resin ratio is controlled perfectly. It comes to our factory frozen so it will not cure. Our factory will then cut the PRE-PREG into specific shapes and lay those shapes into the mold cavity. With specific pressure and heat settings, the molds are cured to produce beautifully uniform parts. The result of this level of control is the elimination of the use of more material than is necessary to do the job and therefore, forego useless propeller weight. Our designed fiber placement is perfectly controlled. Fiber to resin ratio is perfectly controlled. Void content is perfectly controlled. Weight and strength is perfectly controlled. POWERFIN is the FIRST and ONLY propeller manufacturer in the USA to make propellers for Ultralight and LSA (Light Sport Aircraft) using PRE-PREG materials and pressure in the molding process. All the others use cruder techniques that result in blades that are weaker or much, much heavier.
Another aspect to our design is the high compressive strength foam core used in our structure. The only purpose the inside of any bending structure serves is to keep the two outside layers apart under load. Aerospace engineers have found that high compressive strength foam can do that job without adding much weight to the structure. One added benefit to using foam in a high vibration environment is that it is an excellent dampener. POWERFIN propellers use high compressive strength foam as a core material. This is one of the reasons POWERFIN propellers have such a smooth operation and why they have such beneficial low weight and inertial mass.[Back to Top]
Few things are as underrated and misunderstood about small aircraft propellers than MOMENT-OF-INERTIA. Low moment of inertia is critical to the safe, smooth, and long lasting operation of your two-stroke engine and reduction unit. Inertia, by definition, is the reluctance of a mass to accept changes in velocity. When your engine is idling the pulse tries to accelerate the prop and the compression tries to decelerate it. High inertial loads in this situation increase compression and hinder the stroke causing many engines to idle poorly. Most people fiddling with timing and fuel mixture trying to solve this problem never suspect high MOMENT-OF-INERTIA to be the culprit. High MOMENT-OF-INERTIA in a propeller is also bad because the propeller becomes a more effective gyroscope with a higher tendency to remain fixed in space.
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This has three effects.
Low MOMENT-OF-INERTIA in a propeller also means faster access to your available horsepower, reducing spool-up time when you hit the throttle. In the right flying situation a POWERFIN Propeller can pull you out of a jam faster than a propeller with high inertia.
Low MOMENT-OF-INERTIA in a propeller means faster spool-DOWN time, letting a CLUTCHed prop stop sooner!
Rotax has set a limit for how much inertial mass is allowable on the B, C & E Gearboxes. On the A/B-box they want propellers with no more than 3,000 kg/cm2. A 72" Ė 3-blade Ivoprop Ultralight propeller is about 4,500 kg/cm2. The same Warp Drive is over 10,000 kg/cm2. POWERFIN Propellers are 2,500 kg/cm2 for a big three-blade model and 1,800 kg/cm2 for a two- blade model. POWERFIN is the only U.S. manufacturer to have addressed this issue and met the challenge of designing a very durable, low inertia propeller for the Rotax gearboxes.
1. It puts more pressure on the bearings in the final stages of your reduction unit as you turn your aircraft in flight.
2. It causes more adverse turning tendencies due to gyroscopic precession.
3. It reflects vibration that can be felt by the pilot instead of absorbing and dissipating it.
The blade finish of POWERFIN Propellers rivals anything this industry has yet produced. There are UV inhibitors mixed into the materials that we use so your propeller will stay shiny for years. We also include instructions for maintaining the finish against deterioration. Every POWERFIN blade leaves the factory with urethane leading edge tape applied to it. This is standard equipment and is easily replaceable if it becomes worn. The tapes are available from POWERFIN or other aircraft suppliers at a very reasonable cost. See pictures of POWERFIN blades here.
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Every aspect of POWERFIN Propellers exemplifies a precision made product. The use of PRE-PREG carbon fiber and e-glass results in blades that are all molded to within 5-grams total weight of each other. Due to this extremely tight process, POWERFIN can easily match the balance of a needed replacement blade by referencing the number scribed onto each blade's root. This eliminates a great deal of hassle for the customer - who already has enough to deal with...[Back to Top]
We are proud of our Propeller process and the end product and hence we have structured a warranty to prove that. So, if you purchase a POWERFIN propeller and are not satisfied with it for ANY reason, please return it in the same condition as it was shipped from the factory back to POWERFIN within 30-days of purchase and we will refund your full payment. We also offer a year warranty for free replacement of any part containing a defect in materials or craftsmanship. Our goal is to never have a customer who is unhappy with the POWERFIN Propeller. Being humans of this planet, we may make mistakes at times and recommend the wrong propeller diameter or style but we will never be complacent in the face of a dissatisfied customer. Please let us know when you have any concern with your purchased from POWERFIN so we can make it right.[Back to Top]
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"And finally, THANKS...
As we sincerely do appreciate your time to inquiry and research into our propeller product line."