Safety concerns for operating high performance turbine
powered model aircraft have been addressed multiple
times on BVMJets.com/Safety Issues page dating back to
the year 2000.
Recent observations by myself and other experienced
jet pilots of a few "close calls" prompts this reminder
about the extra "personal responsibility" that turbine
pilots are expected to exercise in the pursuit of their
hobby. All of the important points have been addressed
in the "Safety Page" of this website, but it may be
timely to review a few of the most glaring violations in
Vne = Velocity to Never Exceed
The AMA "Turbine Waiver" regulations states that all
turbine power model aircraft operating under AMA
jurisdiction shall have a maximum velocity of 200 mph.
Single engine thrust shall not exceed 45 pounds, and
multiple engine thrust should not exceed 50 pounds
combined. There are also weight classes defined in this
document AMA #110409. In many cases, this Vne is too
high for some models and pilots. Responsible
manufacturers publish the maximum safe (and tested) Vne
for their jet models - usually it can be found on the
front page of the assembly and operation manual of each
If the model you are flying does not have a published
Vne, consult the manufacturer or one of their
representatives to get an answer. Otherwise, it would be
prudent to limit the vehicle to 150 mph if there are any
concerns about the internal integrity of the airframe.
This is even more important now because most airframes
are highly prefabricated from the manufacturer and
inspection of all internal glue joints is not possible.
Rated Engine Thrust
Installing a larger, more powerful turbine engine than
is recommended by the airframe manufacturer, has a few
undesirable consequences. Sure, you can dial down the
maximum thrust, but the increased idle thrust adds
challenges on landing. The total weight of the model
increases by the combination of the engine weight and
extra fuel required, adding structural stress loads
during high "G" maneuvering. And, unless the internal
engineering is professionally accomplished, the heat
inside the model can increase significantly. The
temptation to use all of the available thrust could
result in a structural failure. Operating a model jet at
high altitude locations such as Mexico City (7,382' AMSL)
would be a possible exception to this caution.
Manned aircraft have strict time and number of cycles
maintenance checks that must be performed to F.A.A.
standards. Our in-the-shop hobby time can be partially
dedicated to similar inspections and corrective actions.
The BVM jets "Safety Issues" pages have numerous
articles relating to "Glue Joints", operating in "Bumpy
Air", "Speed Control Devices", "Wing Stress Cracks",
"Servo Control Arms", "Things Still Come
Loose", etc. etc. There is a lot of
experience derived information there.
Flight Line Safety
Low altitude passes should not occur over the runway,
but rather an additional 60-70 feet beyond the far edge
of the runway. In my opinion "Low Altitude" should be
defined as nothing lower than 10 feet above the ground.
This would prevent any possibility of bodily injury, if
for any reason, a person might be on the field. We
cannot rely on flight line communications, they are
subject to human error.
Common Sense - A Final Word
Please know that government regulatory agencies are
observing our activity at events and model club
facilities. It is sensible to error on the safe side.
The future of our exciting, challenging, and most
rewarding sport depends on every jet pilot's acceptance
of this extra "Personal Responsibility".