Fixed & variable Pitch
Background: Gerd Muhlbauer has been a leading light in the propeller business for many years, and was the Technical Chief of Hoffman Propeller before setting up his own business over 25 years ago. This has expanded very successfully, and the company now produces a huge range of propellers for almost all applications, both for fixed and variable-pitch.
MT propellers are effectively the only choice for unlimited level aerobatic aircraft, which is probably the hardest and most demanding application for any propeller. Indeed in every World and European Aerobatic Championship since 1998 every competitor was flying with an MTV variable-pitch propeller!
Applications: MT propellers are available for most aircraft – whether ‘Experimental,’ or for fully certified aircraft. They have a number of intrinsic advantages over other propellers (see over), but in particular are able to give significantly quieter aircraft – this is becoming increasingly important, as well as enhanced performance.
Construction: MTV propellers are of a new design, incorporating the latest lightweight hubs, while the blades are manufactured from compressed laminated wood, covered with composite and a steel leading-edge strip. This combination is considerably lighter than conventional metal propellers, and brings with it a wide range of additional advantages.
The advantages of the MTV propeller are many, but include:
- A wide range of propellers are available, and where quietness is sought, there is the ability to go from two to three blade or three to four blade propellers, without compromising performance, but providing a significantly quieter propeller.
- The wood/composite design of the MT propeller is a superb absorber of vibration, and, particularly, when coupled with dynamic-balancing, all aircraft will be significantly smoother in operation. For example the Piper Malibu has always had problems with cracked super-charger fixtures, and this problem has totally disappeared with MTV propellers. About 400 Malibu’s (of some 800 in service) are now fitted with MTV propellers.
- The advanced blade design typically means that performance for take-off and climb is increased, while cruising speed is certainly the equivalent of other propellers, but typically one or two knots more.
- The vibration damping qualities of the propeller is such that the engines typically do not have any RPM ranges to avoid, and the propellers are far kinder to engines, thus enhancing engine life, as well as protecting airframe and airframe components.
- The propeller has a stainless steel leading-edge, which is harder than aluminium. If it is damaged it can be replaced an infinite number of times. On the other hand, with aluminium blades, although the leading-edge can be ground, after four to six times, the blade will then be below minimum dimensions and has to be discarded.
- In the case of a ground strike, if 75% of the blade is unaffected, then the blade can be rebuilt, rather than being damaged beyond repair. Also in the event of a major ground strike, the chances of serious engine damage are far less with an MTV propeller than with a metal one.
- For aerobatic use, MT propellers are designed to change pitch quickly, which make them ideal in such applications, but also MT aerobatic propellers work in a reverse sense, meaning that should there be a failure of oil pressure to the propeller, they will go into high-pitch, avoiding over-speeding the engine.
- MT propellers are remarkable value, and typically significantly cheaper than conventional alternatives, while giving supreme German technology and quality.
- Easier starting. Because the propeller only has some 25% of the rotational inertia of the equivalent metal propeller, it is much easier to turn and therefore engines start a great deal more easily.
For further information in terms of applications; technical issues – please contact us.