you complete your main rotor blades it is natural to want to paint
the entire blade to make it look great. Unfortunately the rotor
blades are traveling through the air at near the speed of sound
and any particles of dust or rain will blast the paint off. The
paint will begin to chip back from the leading edge and this disrupts
the smooth air flow around the blades that is needed for lift.
The smoother the airfoil surface, the less drag and that means
less power is required. Your blades will also get covered with
bugs when you fly in the summer months and even they will rob
your rotor system of needed power. The blade photo below is typical
of a main rotor blade on a Rotorway helicopter after around 25
hours or flying.
The blade below is a
composite blade that some builders install instead of the factory
blades. I have seen several of these blades with air spaces under
the gel coat surface that breaks away with use. The hole must
then be repaired which changes the balance on your main rotors
The Rotorway main rotor
blade below has several hundred hours on it and the paint edges
have been sanded back to keep the airflow clean.
The blade below was painted
with the first 1 1/4" from the front masked off and polished.
The paint line was then carefully sanded to insure that there
was no ridge that could be felt with the fingers. If you can feel
it, the airflow will be disturbed proportionately. It is important
that the skin to spar seam is painted over to protect the epoxy
in that area.
Here is a closeup of the same blade.
The photo below was taken
during a pre-flight inspecton of a Rotorway Exec 162F while doing
flight training. Just one more thing to keep an eye on. It has
broken during the last flight. This is also why we leave the covers
off during training, so we can find things like this. The cause
of this broken spring is not a design flaw but the spring was
most likely damaged during installation by the builder.
When I went to a student to provide advanced
flight training in his Rotorway 162F that he had been flying regularly
I found this cyclic cable control rod end jam nut had backed off.
The builder had installed withness seal to show a loose nut but
he had not checked this area during his pre-flights and it could
have eventually resulted in a loss of cyclic control. Any steel
thread into aluminum needs to have some form of locking mechanism
to prevent relative movement between the steel and aluminum threads.
If movement is allowed the steel can eventually wear the aluminum
threads to the point that they can no longer hold the steel fitting
and it can pull free causing al loss of control. Check all of
your jam nuts on every pre-flight inspection.