In keeping with Hercules’ toolmaking skills, we have designed and and built apparatus to measure tensile strength brittleness, Young’s modulus (resistance to bending) and modulus of rupture (ultimate strength) of any given wood sample.
Moisture content and density is also an important consideration when selecting timber for propellers and these values are also measured.
Having the apparatus and skills to test the mechanical properties of different wood species, we offer a material testing service to measure the strength of wood samples for aircraft engineers, builders and restorers.
The Izod machine has a swinging pendulum which breaks the wood sample. The energy taken to break the sample is measures enabling us to calculate the brittleness.
MATERIAL STRENGTH TESTING
In aviation structural strength is everything, and unknowns simply aren’t acceptable.
We take the structural integrity of our propellers very seriously. When designing a propeller, calculations are made to ensure the propeller is strong and rigid enough to withstand the intended engine RPM, with a large safety margin.
Wood being an organic material can vary in quality so we have to make sure the materials we use meet to the minimum strength expectations for the species.
The beam testing press measures how much force is needed to bend a sample by a given distance (Young’s Modulus) and also how much force is needed to break the sample (ultimate strength).
Adhesive bond testing
It is essential that our bonded timber joints comply to the expected strength standards. Sample glue joints are pull tested to failure and the adhesive's shear strength is measured.
EVTOL rotor blade root attachment strength test
Tensile pull test of beech timber
Variable pitch blade root hydraulic pull test
Verable pitch blade root attachments
We produce test samples of variable pitch blade root attachments which are hydraulically pulled to destruction in order to prove the strength integrity. Blade roots are tested to at least 2 x maximum service strength plus an overspeed factor. The blade root samples are pulled off centre to simulate the effects of thrust and gyroscopic loads at the same time as the dominant centrifugal force.