Q/A. What are the benefits of your propellers? AeroComposites' propeller designs begin with, and improve upon, the best commercial and military composite propeller technology available today, from all manufacturers. We make use of proven design practices, have designed out known propeller service and operational problems that have been experienced in the field (extensive use of lessons learned), and incorporate the highest strength and most durable aerospace materials available today. AeroComposites propellers offer the best in safety-performance-durability-quality-value.  Specifically, major benefits offered by AeroComposites' propellers include:

• Designed by experienced propeller team with extensive composite propeller design and manufacturing know-how.
• Designs start with proven commercial, military, and general aviation propeller technology.
• Single-piece hub housing, CNC machined starting with a quality aerospace forging (newest and best alloy) that is stress-corrosion free.
• Strongest, toughest blades available --- NOT fatigue life limited.
• Durability (also repairable) provides "LIKE-NEW" performance many times longer than competitor's aluminum and/or wood-core composite blades.
• Blade carbon structural plies, interspersed between fiberglass braided layers for strength and vibration absorption.
• Extra outer fiberglass braids protect inner carbon plies, and allow for surface repairs.
• Toughened and ductile resin, extremely durable, yet field repairable, is NOT affected by hot and dry climates "dry out and blister problem " or moisture.
• High temperature composite/resin cure temperature allows use of any paint color.
• Patented fail-proof composite blade root construction, affords the safest blade retention system in all of aviation.
• All blade composite plies completely wrap around (at base of blade) and are bonded to, locking, corrosion resistant, high strength, and stainless steel rings.  Our patented design results in the safest, most efficient, highest capacity means of composite-to-metal load transfer.
• Blade strength and root construction allow for significantly higher propeller rotational speeds without safety concern.
• Fiberglass braided "socks" eliminate cut edges that could result in blade delamination.
• High density, internal foam core helps with structural shear transfer, and offers protection against blade buckling in cases of bird strike or ground impact.
• Nickel alloy, blade leading edge sheath, is proven as the most durable available.
• Glass braids/carbon/foam/nickel sheath give best overall blade impact protection.
• Blade lightning protection from molded-in (full cord width from root to tip), conductive metal mesh on both blade surfaces.
• Thin and efficient blade airfoils result in low drag, high thrust, and high cruise speed performance.
• Blade in-board airfoil sections include a trailing edge flap, greatly improving acceleration and climb performance without degrading cruise performance.
• Blade outboard sections, stacked/positioned to balance loads on bearings and extend bearing life.
• Blade weight is half that of aluminum blade with HALF the centrifugal load.
• Light blades with large diameter retention bearings result in lowest vibration.
• Blade sweep reduces tip Mach numbers and noise, and avoids tip flutter.
• Blade offset zero's out blade bending stresses under operating centrifugal loads.

Q/A. For which aircraft and engines do you sell propellers? We manufacture constant speed (hydraulic oil) propellers, both 2-bladed and 3-bladed, in diameters ranging from 68 inches to 80 inches. Our propeller models support aircraft applications today with engine powers ranging from 150 hp to 600 hp, and cruise speeds from 150 mph to approaching 400 mph. Currently, our propellers are not  FAA Certified and therefore are for use on experimental aircraft.

Q/A. Do you offer a pusher type propeller?  We offer a pusher propeller option (tractor configuration blades) suitable for use with counter rotating (CCW) engines (e.g. Lycoming LIO-540).  We do have a pusher propeller design completed for use with standard (clockwise rotating) engines (CW) and recently have begun work on tooling fabrication for producing these pusher configuration type blades. There has been a great deal of interest in our propeller technology for pusher propeller applications (e.g. from Velocity aircraft owners).

Q/A. What is included in your propeller price? The propeller prices quoted include a complete, statically balanced, constant speed propeller ready to bolt on your aircraft. Our spinner kit prices include spinner cone, forward and rear bulkheads, alignment of parts, forward bulkhead installed in spinner cone, all mounting hardware, and detailed kit finishing instructions with pictures. We do not include governors which are available from McCauley, Hartzell, or Woodward. The only additional costs are for shipping, custom propeller blade designer paint finishesif opted, and possibly nominal charges if a non-standard hub/spinner design is required for a given application. 

Q/A. Are your propeller prices higher than those of your competition?  Our prices have actually come down more than 25 percent over the last 4 years, in real dollars!  This has been made possible, as our propeller sales volume has increased (take advantage of economy of scale), while still maintaining a reasonable manufacturer's profit margin for our company.  Our propeller prices today, are very competitive.  Prices for our composite propellers are less than half the price of Hartzell composite propellers made using more than 20 year old composite technology.  Our composite propellers are more expensive than aluminum propellers but they offer so many significant advantages.  Our propellers are priced close to MT's composite (wood blades with thin composite outer shell) propeller prices (don't forget import duties and shipping costs) again offering so many significant advantages.  

AeroComposites uses the very best aerospace quality materials, processes, high-tech labor, and design features in our propellers to provide customers the best in propeller safety, performance, durability, and quality. Design features for our propellers include the use of single piece hubs machined from aerospace forgings (not aluminum billets), high strength, non-corrosive stainless steel blade retention rings, special processes to improve fatigue strength and eliminate stress corrosion, best composite materials available, most durable blade leading edge, etc..  While the manufacturing processes we use make our blades/propellers somewhat more expensive than those of other propeller manufacturers, the result is that our propellers offer significant advantages over the competition.  For example, our blades don't pit and corrode, our hubs don't fret and are not prone to stress cracking, our propellers are vibration free over the entire operational RPM envelope, our blades don't dry-out and blister, ect..  A large propeller repair bill (e.g. damaged blades, cracked hub) can easily wipe out any "perceived savings" attributed to somewhat lower propeller acquisition cost. 

Our company charter is to produce advanced technology propellers for general aviation customers at competitive prices which may not be the very lowest. Our standard is that we will not  compromise safety, performance, or durability in designing/manufacturing our propellers. We see ways to reduce the cost of making our propellers but these are not consistent with the high standard of safety and performance that we have adopted.

Q/A. What airfoil geometry is used in your propeller blade designs? The laminar flow blade airfoils used in our propellers are of our own design and are proprietary. The blade sections do feature a visible trailing edge flap on the in-board sections of the blades which improves takeoff and climb performance without degrading performance in cruise.  The radial blade airfoil sections are characterized as having a very low drag bucket over a very wide range of aircraft cruise speeds.  Data taken on our propellers consistently indicates higher climb rates and cruise speeds than those of our competition. 

Q/A. What are the advantages of your resin transfer blade molding process? The Vacuum Assisted Resin Transfer Molding (VARTM) process used in making our composite blades is an environmentally friendly, "state-of-the-art" process that offers many significant advantages over other composite fabrication methods such as vacuum-bagging of wet lay-ups,  autoclaving layups, or compression molding of pre-impregnated composite layers. We have developed proprietary techniques to carefully position the dry composite layers during lay-up of our blades, assuring high strength and the bonus of low manufacturing scrap rate. While the VARTM process is more expensive to use than other composite manufacturing methods, our end product blades are in every way of superior quality. Advantages of VARTM are a controlled and highly repeatable process, total resin saturation of all composite fibers in the layup, and complete resin wetting of metal components (e.g. leading edge sheath). The net result is blades free of resin voids, with an internal structural foam core, with near perfect mass and shape replication, resulting in very low propeller mass and aerodynamic unbalance. A metal leading edge and surface metal mesh lightning protection is molded in with each blade.  The very high strength composite structure allows for the use of very thin, efficient airfoil sections that are at the same time extremely strong and torsionally  stiff.

Q/A. What is the service history record with your constant speed hubs? Initially, we researched data and found that McCauley hubs, with their single-piece forged aluminum construction, have by far the best service history in the industry. We started our propeller business using McCauley hubs in our experimental aircraft applications. With our blades, which weigh less than half that of aluminum blades, this provides very higher centrifugal load safety margins. Today we machine our own hubs that offer many advantages: improved metal grain structure in our forgings, a newer aluminum alloy heat treated for higher strength and better stress corrosion resistance, higher centrifugal load margins, generous blend radii and shot-peening of surfaces for greater fatigue resistance. As part of our quality assurance program, we have disassembled selected propellers with 150 and 250 hours of operational time where inspection has shown as-new-condition of all parts. This program continues with these propellers as more time is accumulated, but we have no reason to require our propellers to have a more frequent overhaul period than the standard 5 years or 2,000-hours, whichever occurs first.

Q/A. How is your blade metal leading edge attached to the blade? Our blade metal leading edge is molded/bonded in place during blade VARTM fabrication, where it is replaceable. The fabrication of the metal leading edge and its bond attachment to the composite blade is based on proven technology developed for commercial and military aircraft propeller and helicopter composite rotor blades. We have conducted shear pull tests to 1250-lbs (limit of test rig) on 1-square inch test samples of the leading edge. No sheath bond damage was sustained in any of these tests.  The requirement for the leading edge to stay attached, based on the centrifugal shear load developed at blade tips at 2700-rpm (more than 7000 g's load), is only 40-lbs. Our leading edge attachment is virtually fail-proof with more than a  25 times margin at 2700 rpm. 

Q/A. How are your composite blades retained in the hub? Our hub retention geometry is similar to standard methods in use where the centrifugal load of each blade is carried by a ball bearing assembly. However, unlike some manufacturers whose designs require two-piece (split) bearing races, our bearing consists of two, larger diameter, one-piece, hardened steel races, locked in place with a two-piece, steel annular retainer inside each hub arm. This approach coupled with our patented composite blade fabrication technique is the best-in-aviation and it is fail-proof!

All of the blade carbon and fiberglass fibers in our blades wrap around two, nested, corrosion resistant, high strength stainless steel rings at the blade root, and are in compression under centrifugal load (20,000-lbs. of pull at 2700-rpm). We have demonstrated in test a 2.5 times margin which was the limit of the test rig.  Analysis predicts that our blade can sustain radial loads exceeding 200,000-lbs. This represents a 10 times margin for the blade itself, compared to 2.0 to 2.5 times for many metal blades. Our blade retention design does not depend on the use of lag bolts, clamping action, bonded joint load transfer through the composite structure, or other methods in use today by other propeller manufacturers that have resulted in serious and costly in-flight and service problems. Because our blades are half the weight of aluminum blades, the centrifugal load of our blades (20,000-lbs.) at 2700-rpm is less than half the centrifugal load on comparable aluminum blades (40,000 to 50,000-lbs.). Our hubs have even higher strength than the hubs used with aluminum blades which means that with our reduced blade loads, our hub strength margins are at least 2.5 times those of the certified hubs used today with aluminum blades. No propellers (composite, aluminum) used in aviation today come close to matching the blade retention system safety margins of our design.

Q/A. How do your propellers perform? Flight tests using our propellers have been conducted on a wide range of experimental category aircraft. These tests have involved our 2-bladed and 3-bladed constant speed propellers, installed on engines with power ratings ranging from 160-hp to more than 450-hp, flying with airspeeds from 180 to speeds approaching 400 mph. Acquired flight data in these tests has consistently shown TAS increases on the order of 5 mph to 7 mph. However, propeller performance involves more than just top end cruise speed. Pilots flying our propellers have reported a quieter cabin environment with substantially reduced vibration, extremely clean operation (no oil weepage), fast speed control response, increased acceleration and climb on takeoff, improved aircraft CG control, no degradation of blade leading edge, etc..  Importantly, there are no engine RPM restrictions (idle to 3100 rpm, 4, 6, and 8 cylinder engines) with AeroComposites' propellers, verified by documented vibration test results (ground, in-flight). 

Remember also that AeroComposites' blades are more durable and will give you "LIKE NEW" performance for a very long time, reducing cost-of-ownership. This is because our leading edge nickel sheath is many times stronger and harder than aluminum (and stainless steel), only showing a "loss of shine" at the leading edge with use.  Aluminum blade leading edges need to be dressed out (filed) and blended resulting in loss of airfoil shape over time and aerodynamic performance.  The best performance day for an aluminum propeller is the first day you fly it!  Our sheath is also replaceable should it be damaged by a very large stone. Also, our toughened resin and protective outer fiberglass braided layers, over thick-wall composite airfoils, can withstand most hard stone strikes with little or no material loss. Of course minor paint loss should be touched up and shallow dings should be filled with a epoxy that we recommend. This toughness and repairability preserves/restores the original airfoil shape for continued high aerodynamic performance.

Q/A. Are there any engine RPM restrictions with your propellers? AeroComposites propellers have been purchased by many customers to replace aluminum propellers with serious/placarded vibration problems. To date, all these installations with our propellers have eliminated any vibration problems (idle to 3100 rpm) and the need for placarded RPM restrictions.  We have performed vibration analysis, conducted instrumented propeller dyno-engine ground testing, ground strobe light testing, and instrumented propeller flight testing at high power settings over the full operational range of engine RPM. In all of the blade strain gauge instrumented tests conducted, the recorded propeller blade excitation data has shown normal operation with very low levels of vibration (also strobe light testing has shown no blade movement (excellent tracking) through the full RPM range. Vibration propeller testing has been performed using a number of engines including the Lycoming IO-360 (180 hp, non-counter weighted, 4-cylinder), Continental IO-520 (300 hp, 6-cylinder), Continental TSIO-550 (350 hp, 6-cylinder), and geared V-8 (440 hp, 8-cylinder) engines. With our light blade weight, strong/stiff composite construction of our blades, vibration absorption properties of our fiberglass/carbon composite resin matrix, foam core, large diameter retention bearings, and balanced blade loads on retention bearings, we have not had nor do we anticipate in the future any RPM restrictions or vibration problems.    

Durability

Q/A. Is your blade leading edge durable and can it be replaced? The leading edge used with our blades is the best material available for propeller applications, and yes, it can be replaced by an approved service center. Our sheath is made of an extremely durable nickel-alloy which is formed on a mandrel in an electrochemical plating process. It is many times harder and up to four times stronger than aluminum. It is thickest at the leading edge, where the most severe, 90-degree impingement, occurs. It is also three times stronger and thicker, as well as being harder (won't crack) and wider than the stainless edge used on wood-core composite blades. These properties give our sheath many times the ballistic (e.g. stone impingement) penetration resistance of these other blades. Our blade leading edge sheaths are very similar to those used on military helicopter rotor blade and commercial aircraft propeller blade leading edges, where they are typically replaced on average after 8,000-hours of service. With use, our leading edge sheaths only show a loss of initial shine at the thin narrow nose portion, becoming glazed at that point by sand and water contact.  There is no need to dress up (file) the leading edge as with aluminum blades with loss in aerodynamic efficiency. Our leading edges are not easily gouged, dented, or cracked.  Should a leading edge have the misfortune of a very large stone strike, there is a standard procedure for replacing our nickel-alloy blade leading edges. The replacement would be done at our factory or at a designated service center which would return the blade to "as-new" condition. 

Q/A. Can your blades be repaired? Yes if the damaged sustained is not too severe (e.g. major ground strike or other significant foreign object (e.g. bird) impact/strike). The resin used in our blades is the latest formulation of a toughened resin that is extremely ductile and durable. When combined with our thin, but thick walled, laminate airfoils of many fiberglass braids and carbon structural plies over a structural foam core, our blades are very resistant to foreign object damage. The erosion resistant paint used by our manufacturing team member, American Propeller Service of Redding, California, has been service-proven on propellers over many years. We have had reports of aircraft coming down through rain at over 300 mph with no blade paint damage, where paint on the composite wings was vapor blasted away.  However, if operating in a very severe environment and paint loss did occur, the blade paint should be touched up to protect any exposed metal lightning protection mesh, molded into blade surfaces immediately below the paint. Our blade construction uses three layers of fiberglass braid just below the aluminum mesh, providing protection to the structural carbon fiber layers deeper inside of the blade. Small nicks that do not extend deeper than 0.020 inch into the surface can be filled with an approved epoxy, sanded smooth and repainted. In the highly unlikely event that deeper, more extensive damage should occur to the blade surface, the blade/prop should be sent to our approved repair center where it can be repaired easily using a common fiberglass/resin repair technique.

Q/A. Do you have a placard restricting your propeller from operating at certain RPM's? No. We have conducted extensive vibration survey testing for a wide range of aircraft/engine applications and have not found any excitation of vibration modes in the normal operational engine RPM range (idle to 3100 rpm) for general aviation aircraft. We have an on-going program to further study the vibration characteristics of our 2-bladed and 3-bladed propellers for new engine applications. Our propeller blades are very light, strong, and stiff and have internal vibration damping provision in their composite design which results in very smooth propeller operation.

Q/A. Have your propellers exhibited vibration free operation where other propellers have not? Yes. An example is an aircraft application, with a non-counter balanced Lycoming IO-360 engine, where the owner was experiencing severe vibration in the range of 2100 to 2300 rpm. The propeller installed on the aircraft was a 2-bladed aluminum propeller. With the AeroComposites' propeller, no vibration was encountered over the full range of RPM and power settings. The owner reported very smooth, vibration free, operation through the flight envelope and an added benefit was cruise speed  increased by 5 mph.  We have had only one installation to date (4-cylinder engine) where the engine and our propeller was reported to have benefited from having a dynamic balance done following installation of our propeller on the aircraft. 

Q/A. Do you balance your propellers? Yes. During the final assembly of our new propellers, the blades are statically balanced as a set and then the entire propeller assembly is statically balanced.

Q/A. Should I plan on having your propeller dynamically balanced on my aircraft? This is really the owners choice. Our individual propeller blades are very closely matched in weight as a result of the Vacuum Assist Resin Transfer Molding molding method used.  In addition, our propeller blades are statically balanced as a set at the time of  propeller assembly and the entire propeller assembly is then statically balanced. Also, our composite blades are less than half the weight of aluminum blades and any small unbalance is not as easily felt. With one exception, our customers have reported very smooth, vibration free operation with our propellers over their flight envelopes. However, one of our customers with one of our 2-blade propellers and non-counter weighted Lycoming IO-360 engine, felt a need for a dynamic balance.  The dynamic balance conducted by a propeller shop resulted in adding some small balance weight(s) on the ring gear at the front of the engine to compensate for unbalances of the rotating assembly (engine, propeller, alternator, magnetos).  As a result of the dynamic balance, he reported that the installation of our propeller was as smooth as the propeller he previously owned.  In the case of 4-cylinder engines, it certainly wouldn't hurt to have a dynamic balance of the propeller/engine assembly done.

Hubs/Controls

Q/A. What do you use for constant speed propeller hubs? Initially, we started the business using McCauley hubs (single piece forged/machined housing) that, in our opinion, were the most reliable and trouble free hubs available. We are now machining our own constant speed hubs of similar design (forging, single piece machined housing), where we have incorporated a number of improvements that provide added safety margin and durability.

Q/A. Do you sell fixed pitch propellers? No.  Our propellers have been designed with high performance, 160 hp to 600 hp engine, single engine aircraft (e.g. Lancair, Glasair, F1 Rocket, RV,s, Express, Seawind) in mind. We sell only constant speed (hydraulic-oil actuated) propellers.

Q/A. Do you have a hub that will properly mate with my engine flange? Yes for most applications. Our hub forgings have a long neck that can be machined to accommodate most any desired hub length and engine flange bolt/pin mounting configuration.

Q/A. What is the construction material for your spinners? The spinner cone and forward and rear bulkheads are generally of composite construction being made of fiberglass, carbon or a combination of both, depending on the aircraft application. In some installations, the back bulkhead is made of thick spun metal (heat treated for stress relief).  Our spinner kits are customized for each aircraft type and include spinner cone, forward and r