Sensenich, arguably the best-known manufacturer of wooden propellers, has been around for almost 100 years. It has a fascinating history, but what does the future hold for this remarkable company?
To gain greater insight, we spoke to Sensenich’s Steve Boser, vice president, engineering. Boser has been with Sensenich from 1993, when he joined the company as a junior design engineer. At the time, rather ironically, he was a glider pilot, although he has since moved on to flying propeller-driven aircraft.
The company was incorporated in 1932, but it began in rural Pennsylvania during the 1920s, when two brothers, Harry and Martin Sensenich, who loved to tinker, procured an old World War I-era engine. According to Boser, they “proceeded to fit it to a wagon, a sled, and different contraptions they could find on their dairy farm. Their wagon worked well. It was called a ‘Wind Wagon’, but eventually they were banned from taking it into town.” The brothers then fitted the engine to a snow sled. One winter, while operating on ice, the brothers’ unique air-driven vehicle crashed, breaking its expensive propeller. At the time, it was rare for someone to be knowledgeable about propellers. Boser explained, “They were pretty good with their hands, so they thought, ‘hey, let’s make our own propeller!’”
The brothers successfully crafted a propeller for their sled. Soon, local pilots took notice and reasoned, “If you can make a propeller for that thing, you can make propellers for our aircraft.” Boser continued, “They started carving aircraft propellers, and by the beginning of World War II, they were the largest manufacturer of wooden propellers in the world. We still have that title today.” During the Second World War, which lasted from 1939 to 1945, Sensenich had more than 400 employees crafting propellers 24 hours a day to support the war effort. These propellers were primarily for liaison aircraft and trainers, as well as experimental projects.
Soon after the war, Sensenich produced a tremendous number of propellers for private light aircraft. Later, in the late 1940s, the company diversified and began making metal fixed-pitch propellers, while also servicing and maintaining other companies’ propellers, in addition to manufacturing a variety of wooden products. During the 1950s, Sensenich also began designing and manufacturing target drone propellers, as well as airboat propellers. Airboats, which have grown in popularity in places such as Florida, are essentially flat-bottom boats pushed by propellers, which are similar in appearance to those found on aircraft. Today, Sensenich produces more airboat propellers than aircraft propellers.
By the late 1980s, the company had been operating separate divisions for propellers and for wood products. The Sensenich family was forced to sell one of its divisions, either propeller manufacturing or its wood product division, which made table tops and bench seats. A Philadelphian family purchased the propeller company and continues to own Sensenich Propellers to this day. In 1994, the company’s three divisions, namely wood propellers, metal propellers and its service division, were separated. The service division had a management buyout, while the wooden propeller division was moved to Florida, the primary market for airboat propellers. The metal propeller division remained in Pennsylvania. In the late 1990s, Sensenich turned its focus to composite propellers for aircraft and airboats, while also ramping up production of unmanned aircraft propellers.
Today, Sensenich has about twenty employees in Pennsylvania, where metal propellers are produced, and about fifty employees in Florida, where the company focusses on wooden and composite propellers.
In terms of aircraft. Sensenich propellers are primarily used by experimental aircraft, trainers and vintage aircraft. Most of the company’s wooden propellers are used by vintage or antique aircraft. Sensenich produces about 4,000 wooden propellers per year, although, due to demand, its carbon fibre propeller production numbers increase significantly every year. How has covid-19 restrictions affected Sensenich? According to Boser, “Last year was probably the busiest year of the past ten years. This year is off to an even better start.” He continued, “When people are at home, they have more time on their hands. They need propellers because they are either working on kit airplanes or they are out flying.”
Sensenich currently produces about 150 to 200 composite propellers per month. Is that where the future lies? “Most of the development is on the carbon fibre product line,” explained Boser. “Wood is economical for developing a propeller in a short timeframe. It requires minimal tooling to make a wooden propeller. The engineering requirements for wooden propellers are much less than metal or carbon props, so new wood props can be made in a couple weeks. A metal prop requires vibration testing for good service life. That is an incredibly involved project and it’s a fairly mature product line. Carbon fibre offers advantages in strength, weight and configuration, with engineering demands between wood propellers and metal propellers.”
What about unmanned aircraft? “We do see a lot of potential with UAVs (Unmanned Aerial Vehicles) in the future, but our sales are fairly steady.” Sensenich develops propellers specifically for mid-size, or tactical-size, UAVs. “We are doing product development across the board with all our products,” said Boser. “We have just received an stc (Supplemental Type Certificate) from the FAA for installation of one of our composite two-bladed propellers on STOL (Short Take-Off and Landing) aircraft. We plan on doing a further STC for lower horsepower SuperCubs. Then we will be looking very closely at the market before we decide on follow-on STCs. The light sport market is very active too. We recently released a number of new prop designs for the light sport and experimental market.” Intriguingly, Boser also mentioned, “We have some pretty exciting things coming up. I don’t want to give out too much about that, but it’s a very new area for us.”
“The recently released STOL propeller for bush planes is very exciting for us,” Boser added. “We are preparing to apply for a Canadian STC.”
Of course, the development of the eVTOL (Electric Vertical Take-Off and Landing) industry is quite exciting. “We have been remarkably busy prototyping for that market, and we have become one of the top fabricators for prototypes and test articles for the eVTOL market.” He added that, “we deal with mature but innovative programmes. There is a whole range of projects out there, so we focus on the ones where we can have the most impact and provide the most value.
The North Star Practices’ (NSP) purpose is to improve safety in floatplane operations, but what exactly is it and how does it benefit the industry?
To find out more about the NSP, we spoke with Jim Hartwell, an experienced pilot who is currently a member of the Air Carriers Safety Working Group and Northern Air Transport Association (NATA). Hartwell, who lives in Campbell River, BC, started his career as a pilot in Saskatchewan during the 1970s, before gaining flying experience in Manitoba and the Northwest Territories. He then returned to his home province to fly floatplanes on the British Columbian coast. During the early stages of the safety programme’s development, Hartwell was serving as administrator for the Floatplane Operators’ Association, which has since been absorbed into NATA. Today, he is actively working on and promoting the North Star Practices in the aviation industry.
From 2000 to 2009, there were 111 fatal aviation accidents in BC, which resulted in more than 200 deaths, of which 85 were onboard commercial operators’ aircraft. In 2012, a panel of aviation experts presented a report to the Chief Coroner of BC, who then provided recommendations to Transport Canada, NavCanada, WorkSafeBC and the BC Forest Safety Council. Hoping to see a consistent set of safety practices, which could be used by operators who fly workers into work sites, the BC Forest Safety Council approached the Floatplane Operators’ Association for assistance in developing a safety programme to reduce the number of accidents in the region. As a result, the Air Carriers Safety Working Group (ACSWG) was formed.
The ACSWG consists of Jim Hartwell, BC Forest Safety Council’s Dustin Meierhofer, experienced seaplane pilot and accident investigator Vince Crooks, as well as NATA Executive Director Glenn Priestly. The North Star Practices, as the safety programme was named, is a set of operating standards and procedures, which includes an auditing system that provides assurance to clients, regulators and the public that an operator has not only met the basic Transport Canada regulations, but operates above those regulations at a higher standard. To operators, the NSP is intended to improve business performance by enhancing safety in an efficient and effective manner. Pilots benefit from the programme, as it provides guidance on safe practices and assists them in making decisions. “We are trying to encourage operators to put this programme into their safety management systems,” said Hartwell. “It is an easy fit.”
For the most part, the NSP relies on self-auditing, but every third year the operator is audited by an independent auditor. That said, how would one know whether an operator is compliant throughout the three-year period? Well, the programme requires operators to make use of satellite tracking, primarily for safety reasons, but also so that, on one or two occasions during the year, an operator’s flights can be monitored by the ACSWG. This adds an element of transparency to the programme. All of the practices contained within the NSP, along with all relevant documentation and information are available on www.northstarpractices.org. An operator that meets the required level of compliance is awarded a ‘North Star’, a symbol which can be displayed to indicate that it is an approved ‘North Star’ operator. In Hartwell’s words, “If you see that logo on the side of an airplane or inside an office, it is indicative that the operator is making a concerted effort to improve safety.”
So far, response from the industry has been positive, as operators are keen to receive recognition for their safety standards. “There is a wanting for a consistent set of safety practices,” said Hartwell. “I think it is timely for the industry to take a closer look and see what it can do to improve safety.”
By investing in safety, especially in this case in the west coast, where flying conditions can be challenging, an operator can expect to not only improve business performance, but earn favour from their clients, peers and the public. For further information, please visit www.northstarpractices.org.
Propellers have been used on aircraft for almost 115 years and have evolved to become more efficient and reliable, but do we really understand the tremendous forces and corrosion to which propellers are exposed? How frequently should an aircraft propeller be overhauled? Is the process absolutely necessary? What happens during an overhaul? To find answers to these questions, we paid a visit to Aero Propeller of Calgary.
Located near Calgary International Airport in Alberta, Aero Propeller of Calgary was founded in 1979. Two of its owners, Gord Thompson and Nash Javer, have been with the company since it first opened its doors nearly forty years ago. In 2008, they were joined by Kevin Samuel, an experienced aircraft maintenance engineer and structural technician. Combined, they have more than a century of experience in propeller maintenance. Most of the propellers that enter their workshop belong to general aviation and light commercial aircraft, but the team occasionally works on more interesting examples, such as that of a Hawker Hurricane and Douglas DC-6. When it comes to propeller maintenance, these men have seen it all and were happy to talk about overhauls in the context of aviation safety.
When determining the when a propeller, or related components, need to be overhauled, flight time or calendar dates are not the only factors one should consider. It is important to take operating conditions and the environment into consideration.
That said, what does an overhaul entail? The first step is to mount the propeller and visually inspect it. The paint is removed and blades are examined to see if they had been damaged in any way, and to measure dimensions to determine whether they can be overhauled. Once the propeller has been taken apart, the basic components are cleaned and degreased. The next step is to repair the damage and ensure that the components are within the manufacturer’s dimensional limits. All major components are then sent to a certified workshop for non-destructive inspection. Next, components are polished and dipped in a solution for corrosion protection, before being painted and receiving a durable polyurethane coating. Finally, the propeller is reassembled and set according to the manufacturer’s overhaul manual.
Internal corrosion is extremely dangerous and can only be detected when all the components have been taken a part and cleaned in a workshop. The importance of propeller inspections and overhauls cannot be overstated. When experiencing an engine failure, for the most part, the aircraft can glide and complete a safe forced landing. If, on the other hand, a propeller blade separates, the remainder of the flight can be considerably more eventful, if not catastrophic.
For further information on propeller maintenance, or advice regarding purchasing or owning a propeller, please contact Aero Propeller of Calgary at 403-291-9400.
Information on how frequently propellers need to be overhauled can be found on Transport Canada’s website, www.tc.gc.ca, in the Canadian Aviation Regulations (CARs) section.
Analyzing or monitoring flight data is not a new concept, but it is surprising just how many misconceptions and myths there are regarding this remarkably important tool, especially now that modern technology has made it more accessible to smaller aircraft operators.
What exactly is Flight Data Monitoring (FDM) and how does it benefit operators? To find out, we contacted Dion Bozec of Scaled Analytics, based in Ottawa, on, who is passionate about developing modern FDM programmes.
In a nutshell, FDM, also commonly known as Flight Operations Quality Assurance (FOQA) or Flight Data Analysis (FDA), is a programme in which flight data is recorded and analyzed, with the goal of improving operating procedures and safety. With the right FDM system in place, operators benefit from increased operational efficiency and profitability.
According to Bozec, one of the biggest myths or assumptions is that FDM is a punitive programme, intended to evaluate pilots. Instead, FDM programmes are designed to look at trends, rather than individual performance, benefiting the entire company, including its pilots.
Many operators also erroneously believe that FDM is expensive, difficult to implement and only useful for airlines. In the past, FDM or FOQA systems were complex, requiring expensive hardware, highly specialized software and a host of engineers and it experts to manage the programme. Thankfully, technology has progressed to the point where this is no longer the case. Today, FDM is accessible and beneficial to any operator, regardless of the size of its fleet, even if it has only one light aircraft or helicopter.
FDM was originally developed to enhance safety and it continues to serve as a valuable component of safety management systems, but there is considerably more to the story than that. “A programme that involves reviewing flight data can benefit many departments within an organization, besides the safety department,” said Bozec. “An FDM programme can be extended to improving operational efficiency, monitoring maintenance events, monitoring or improving fuel efficiency, improving training programmes and reducing maintenance trouble shooting times, among other uses.”
As an example, with the use of FDM, an operator with only one aircraft in its fleet was able to detect a recurring problem with unstable approaches. A trend was discovered, measures were put in place and the number of unstable approaches was dramatically reduced.
Another operator had occasional overtemp problems with a turboprop engine on one of its aircraft. Each time an overtemp was indicated, the aircraft was grounded and its flight data recorder sent to the recorder’s manufacturer, which would download the data file and send it to the operator. On each occasion, the process would take five days, before the decision on whether the aircraft could fly was made. Now, with more modern techniques, retrieving the same information would take mere minutes, dramatically reducing the aircraft’s time on the ground.
Understanding the process
How exactly does FDM work? The first step is to record flight data. Most transport aircraft and helicopters have crash resistant Flight Data Recorders (FDR), called ‘black boxes’ by the media. These data recorders serve as hard drives, storing all the information sent to it by the aircraft’s Flight Data Acquisition Unit (FDAU).
Data can be recovered with a download unit and used for FDM, but there are disadvantages to using an FDR for this purpose. FDRs are only required to record 25 hours of data, download units are expensive and, depending on the aircraft, it might be difficult to access.
As a result, it might make more sense to use a Quick Access Recorder (QAR). This device is effectively a flight data recorder that is not crash survivable. Compared with an FDR, a QAR is small, light, easily accessible, more affordable and able to record more than 400 hours of information.
That said, these data recorders may not even be necessary. If the aircraft has modern avionics, such as the Garmin G1000, data can simply be saved on a memory card and used as part of an FDM programme. This can be particularly useful to smaller commercial operators or flying schools, as glass cockpits have become increasingly popular in even light general aviation aircraft.
Once the data has been downloaded, it needs to be processed by specialized software, which converts raw binary data into meaningful information. The software also looks for ‘events’ or situations where predefined limits were exceeded.
The resulting statistics and ‘events’ are then reviewed by a flight data analyst, who is able to identify unsafe or inefficient trends in flight operations. These steps can be accomplished with the help of a service provider. This would be particularly useful to smaller operators, which would otherwise need to employ a data analyst.
Once the information has been reviewed and examined, an analyst presents it to the operator’s decisionmakers in the form of charts or flight animations. Actionable, informed decisions can then be made to improve safety, efficiency and profitability. By continuously monitoring flight data, the impact and value of those decisions can be measured as the organization keeps working toward perfection.
In recent years, the cost of technology has become more affordable, creating real opportunities for smaller operators to benefit from FDM. With solutions provided by the likes of Scaled Analytics, decisionmakers and maintenance engineers are now able to access vital flight data and statistics online from anywhere in the world, quicker than ever.
For further information on how to benefit from the latest technology in Flight Data Monitoring, visit www.scaledanalytics.com