Material Selection

Our expert craftspeople personally select precious and seasoned woods like MAPLE, ASH, BIRCH, MAHOGANY, CEDAR and SPRUCE for inclusion into our propellers.
New materials are regularly studied, and all material batches are subjected to destructive tests with special tools and test rigs in order to constantly improve adhesion between these different woods
Samples of wood have even been held immersed in water since 1970. They are still there, and despite being heavily saturated, the glue joints remain in very good condition to this day!

BLADE CONSTRUCTION

The GT-BLADES are made of wooden and composite mixed construction. The blade root is made of impregnated and compressed wood and the aerodynamic blade part is made of light weight wood. On propellers with hubs, a special threaded conical aluminium bush joins the blade to the hub.

Blades are made from bonded sandwiches of the various types of wood, glued with high performance aircraft glues, hand shaped then finished to exacting tolerances by cnc cutting machines

The leading edge protection is provided by a further composite strip bonded to the leading edge giving added resistance to damage from grass, stones and rain etc. during operation. This is easily replaceable in case of damage.

The Vintage style propellers are protected by a special leading edge guard made of high resistance modern composite material, particularly designed and shaped as original nostalgic propellers.

The entire blade surface is composite covered with two or more layers of fibre or carbon fabric. Several lacquer layers are applied for blade protection against erosion, moisture, sun rays etc.

Blades are usually painted black on the reversed side to reduce sun glare and the tips are painted in high viz stripes for visibility and safety.

TESTING

Very heavy fatigue, destructive, acoustic and static thrust tests and aerodynamic balancing procedures are carried out. All types of rain conditions and take-offs from rough runways are simulated on all types of propeller, both fixed and variable pitch, using a sliding test bench equipped with a 165HP engine

Several blade retention samples made of impregnated wood were tested in various technical research centers with impressive results:

Example:
A 60. mm diameter sample of the blade root of the GT design for Rotax engines:
912 ,912-S, 914, 80/130 hp with max propeller rotation of 2700 rpm, showed an average tear test load result of 22.000 KGf

Please note:
The GT blades mentioned above weight about 1.5 to 1.8 kg,s each.
At this weight the root load forces at max engine rpm of 2550, standard of rotax 912/914 family, is 2.700 kgf per blade.

The application safety factor of GT blades roots result is that the GT blades for Rotax applications are 7 times stronger than required by Rotax engine operating at full power in service!