Those of you talking check rides this weekend, go on the Facebook page and leave a comment with some information about you ride!
Aerodynamics
The previous two newsletters talked about the airfoil and ETL, refer back if you need a refresher.
Transverse Flow Effect
The definition from the Helicopter Oral Exam guide is, "As the helicopter accelerates in forward flight, induced flow drops near zero at the forward disc area and increases at the aft disc area. This increases the AoA at the front disc area causing the rotor blade to flap up, and reduces AoA at the aft disc are causing the rotor blade to flap down. The result is a tendency for the helicopter to roll slightly to the right as it accelerates through approximately 20 kts or if the headwind is approximately 20 kts."
At the aft section the airflow is coming in vertically.
(Causing smaller AoA)
The forward disc section has air moving in horizontally.
(Causing larger AoA)
This causes unequal amounts of lift over the rotor system(dissymmetry of lift). When dissymmetry of lift happens, blade flapping accounts for it, which then the forward disc flaps up to reduce the AoA and the aft disc flaps down the increase AoA. For the most part this equalizes lift over the rotor system, but not completely. So there is a force downward on the rotors in the aft section and upward on the rotors in the forward section. Gyroscopic Precession tells us that with the spinning disc those forces will be seen about 90 degrees later in the direction of rotation(a force upward on the left section and downward on the right section). This is the cause of the right roll. When ever blade flapping occurs, vibrations occur, in transverse flow effect there is a lot of flapping to account for dissymmetry of lift, causing the vibrations.
When you get TFE?
-Accelerating through about 20kts
-With 20kts of relative wind into the rotor system
Symptoms?
-Vibrations
-Roll right
Pilot action?
Continue accelerating into ETL
Commercial Answer
Going through the photo flight scenario from last newsletter and asking the question....
Is this flight on the commercial certificate alone or with a company?
If Alone, is the job listed in part 119?
If Yes,
If common carriage is Not involved, then can be done, just make sure you comply with and other limitations listed in part 119
If common carriage is involved, then cannot do it.
If No, then most likely cannot be done.... Unless It can be considered a "Private carriage" flight.
If Company, is the company, pilot, and helicopter certified for the operation? (EX. an agriculture part 137 job needs an 137 operator, 137 helicopter, and 137 check out pilot)
If yes, then can do.
If No, then must get rated to do the job.
If ever common carriage is involved, then the job needs to be done under part 135 or part 121.
This job is done on your own and as long as common carriage is not involved you can do it.
There is no distance limitation on photo flights that the regs say anyways.
Landing to get fuel is necessary for the flight to be accomplished as long as the photographer doesn't take any pictures on the ground or purchase anything at the fuel stops.
You can advertise for this because common carriage is still not involved as long as you do not transport person or property, so make sure that you terminate the flight at the same airport you started the flight at.
Resources
For some help regarding commercial photo flights, this forum mainly talks about photo flight distance limitation.
Here is a Link to JustHelicopters.com
Company website
For some information about LEA’s flight school, maintenance facility, commercial operations, or aircraft sales, visit the company website.
Here is a Link to FlyBend.com
Facebook
Also Flow Leading Edge on Facebook
Here is a Link to the Facebook page.
NTSB Accident Report
For a search query of reports accidents to the NTSB
Here is a Link to ntsb.gov
R22 Preflight written instructions, here is a good Link with pictures and text about a R22 preflight.
And this is the sublink that goes to and miscellaneous page with some really good information about the helicopter and components that aren't identified on the preflight check list.
