Without a method of converting the power produced by the engine into useful thrust an aircraft would just be sitting still and creating a lot of noise and not get anywhere. In the past, all kinds of different propeller designs were tried: sometimes flat wooden blades, from one bladed counter weighted to multiple blade models rotating at various speeds.
Most aircraft propellers are nowadays build from a fine selection of materials like wood, metals and carbon or other fibers to form a strong construction.
Fiti Design Ltd was founded in 2000 by Josef Faturík who has many years of experience in the industry, after having worked for STRAKA FLY, later JUNKERS. Since 1978 until present he is a pilot and designer of hang-gliders and power hang-gliders including engines of those machines.
The company designs and produces composite products for ultra-light aircraft and sports flying aircraft. The firm also provides technical consulting services concerning its products. Their core business is the manufacture of composite propellers, fixed, on-ground adjustable and in-flight adjustable, for ultra-light aircraft. They are also usable for Light Sport Aircraft. Contact Fiti for details.
These ground adjustable propellers are available in two blade versions suitable for Rotax engines 447 and 503 (two stroke) with a diameter of 1580 mm. The weight is 3.6 kg (7.9 lbs).
The three bladed version is suitable for the Rotax 503/582 (two stroke) and 912 versions. The diameter is 1580 mm and weight a bit higher (one more blade) of 4.9 kg (10.8 lbs). Fiti als has a propeller dedicated for the glider tow aircraft.
On their product page, Fiti shows only one type of in-flight adjustable propeller. It uses the same blades but the hub is capable to set the blade angle. There is no mention of how the blades are controlled: oil, electronic or mechanical. The weight with three blades is 7.5 kg (16.5 lbs).
Spinners are available for the two and three blade hubs. There are two types with a difference in diameter: 235 mm (two bladed model) and 260 mm (three). They are made of carbon fiber, used for the base and fiberglass (L285 epoxy resin) for the spinner itself.
Propellers also require minimum maintenance consisting of regular cleaning, inspections and checks. Inspection after 50 flight hours is carried out by the owner by removing the propeller spinner and tightening the bolts with the prescribed torque as per point 4 of the installation procedure manual. Inspection after 150 flight hours or one year (which ever comes first) is carried out by the manufacturer.
Clean the propeller blade surface with fresh lukewarm water with a non-corrosive detergent added. My advise is to clean the propeller after each flying day to ease the inspection for any damage caused by stones and this will also remove any insect residue which may result in corrosion.
And while you are taking care of the propeller, do clean the rest of the aircraft too...;-)
Fiti Design s.r.o. can be contacted at the following addresses:
|Fiti Design s.r.o.|
|252 30 Řevnice, Czech Republic|
|+420 724 327 922|
Text and images used with permission (pending) of Fiti Design s.r.o.Written by EAI.