denningte
Member
Ladies and Gents,
The most important point being missed here is the time before the canyon turn requirement. I teach pilots to avoid getting into the situation where max performance is required and particularly when the performance envelope is bounded by granite or trees on either side. You fly for recreation and there is no compelling requirement to scare the ^&#% out of yourself at any time. Keep your head out of the “up and locked” position as my father used to say.
When I cover this subject in training, I note to the trainee that max performance turning is not well documented in the POH of any GA aircraft. Turning performance is a functional of CAS, G-Load, bank angle, and power. You say, “well no ^&#% TD. Tell us something we don’t know.” Here is a nugget – where ever you learned the “canyon turn” it worked for that day at that terrain, DA, temperature, prop setting, mixture, throttle, thermalling or orographic condition, flap setting, entry airspeed, and exit airspeed. Oh yes, and how much crap you had in your airplane at the time. Anywhere else it will be different – maybe tighter, maybe looser. The point is don’t calibrate your eyeball with, and think you can always thread the needle with what you learned at McCall.
I have read and heard techniques from others. They all have some merit but usually fall short in some consideration where they might not work. In fighter aviation, squeezing the most out of your turn capability is (was) the most desired goal of being a competent visual fighter. It was not a static turn situation. Airspeed bled off rapidly as you loaded up the swept wings and the turn rate (deg/sec) dropped as the radius shrunk to a minimum then began to expand again. The expansion was caused by having to convert lift from the turn into the vertical to counteract sink at low speed. In a GA aircraft with high-aspect ratio wings the rate/radius is not so dynamic in the actual turn, but put high DA and a sinking downdraft on the hill side and it will be a whole different ball game. Between Vy and Vs in a turn you decrease lift effectiveness on the wings that makes them less effective in the turn. I use Vy as a target because it is above turning stall for a max performance turn in the Husky. If you have never developed a seat feel for where your Husky stalls in a steep turn, you should. It is an excellent cue to pull short of in an emergency turn. Do it with the flap handle in hand and feel how that changes the dynamics. Do it with the aircraft loaded in safari configuration so you don’t fool yourself into believing the turn with you, an empty backseat, and ¼ fuel is the right sight picture.
I teach flying at or above maneuvering speed (Va) around hills and canyons. If it is bumpy, be at Va. I also have the student tell me their escape plan periodically just like a CFI would have a new pre-solo student call out landing areas. I go through three options (luckily I have local terrain to demonstrate each) – the uphill turn to bleed down to Va in a chandelle-like turn not to go below Vx if smooth or Vy if bumpy. The level turn is the same speed range. The descending turn is tighter and only available if terrain allows. In the descending turn you convert potential to kinetic energy giving up altitude to have more energy to bleed on the pull in the turn. All of these are entered with simultaneous transition to full power (throttle and RPM primary, mixture secondary) and hand on the flap handle to assist the performance of the wing. In the Husky, 10-20 is plenty. I rarely go over 10. The preferred techniques are in the order I gave them.
NOTE: your Husky POH may be incorrect in Vx/Vy numbers. Some manuals show Vx and Vy crossing at 10k and some don’t. If you are clear on Vx/Vy physics, they should NEVER cross and continue. They change with DA and merge at the service ceiling of the aircraft. According to my POH, I should not be able to get over 10k DA – I guess it missed that memo last week going by Longs Peak at 14k. The Vx and Vy I look for is DA appropriate. I have the right numbers from a later manual.
I end with the thought that the 180 point is not the end of your problem. You need speed and power to recover to a safe place. An incredibly tight turn followed by a stall into the trees below scores no style points. The reason you got here in the first place was terribly bad foresight or unexpected sink conditions. In either case, having an airplane that is in a solid flying envelope after the turn helps to offset the laundry emergency that accompanies these kinds of adventures.
TD
The most important point being missed here is the time before the canyon turn requirement. I teach pilots to avoid getting into the situation where max performance is required and particularly when the performance envelope is bounded by granite or trees on either side. You fly for recreation and there is no compelling requirement to scare the ^&#% out of yourself at any time. Keep your head out of the “up and locked” position as my father used to say.
When I cover this subject in training, I note to the trainee that max performance turning is not well documented in the POH of any GA aircraft. Turning performance is a functional of CAS, G-Load, bank angle, and power. You say, “well no ^&#% TD. Tell us something we don’t know.” Here is a nugget – where ever you learned the “canyon turn” it worked for that day at that terrain, DA, temperature, prop setting, mixture, throttle, thermalling or orographic condition, flap setting, entry airspeed, and exit airspeed. Oh yes, and how much crap you had in your airplane at the time. Anywhere else it will be different – maybe tighter, maybe looser. The point is don’t calibrate your eyeball with, and think you can always thread the needle with what you learned at McCall.
I have read and heard techniques from others. They all have some merit but usually fall short in some consideration where they might not work. In fighter aviation, squeezing the most out of your turn capability is (was) the most desired goal of being a competent visual fighter. It was not a static turn situation. Airspeed bled off rapidly as you loaded up the swept wings and the turn rate (deg/sec) dropped as the radius shrunk to a minimum then began to expand again. The expansion was caused by having to convert lift from the turn into the vertical to counteract sink at low speed. In a GA aircraft with high-aspect ratio wings the rate/radius is not so dynamic in the actual turn, but put high DA and a sinking downdraft on the hill side and it will be a whole different ball game. Between Vy and Vs in a turn you decrease lift effectiveness on the wings that makes them less effective in the turn. I use Vy as a target because it is above turning stall for a max performance turn in the Husky. If you have never developed a seat feel for where your Husky stalls in a steep turn, you should. It is an excellent cue to pull short of in an emergency turn. Do it with the flap handle in hand and feel how that changes the dynamics. Do it with the aircraft loaded in safari configuration so you don’t fool yourself into believing the turn with you, an empty backseat, and ¼ fuel is the right sight picture.
I teach flying at or above maneuvering speed (Va) around hills and canyons. If it is bumpy, be at Va. I also have the student tell me their escape plan periodically just like a CFI would have a new pre-solo student call out landing areas. I go through three options (luckily I have local terrain to demonstrate each) – the uphill turn to bleed down to Va in a chandelle-like turn not to go below Vx if smooth or Vy if bumpy. The level turn is the same speed range. The descending turn is tighter and only available if terrain allows. In the descending turn you convert potential to kinetic energy giving up altitude to have more energy to bleed on the pull in the turn. All of these are entered with simultaneous transition to full power (throttle and RPM primary, mixture secondary) and hand on the flap handle to assist the performance of the wing. In the Husky, 10-20 is plenty. I rarely go over 10. The preferred techniques are in the order I gave them.
NOTE: your Husky POH may be incorrect in Vx/Vy numbers. Some manuals show Vx and Vy crossing at 10k and some don’t. If you are clear on Vx/Vy physics, they should NEVER cross and continue. They change with DA and merge at the service ceiling of the aircraft. According to my POH, I should not be able to get over 10k DA – I guess it missed that memo last week going by Longs Peak at 14k. The Vx and Vy I look for is DA appropriate. I have the right numbers from a later manual.
I end with the thought that the 180 point is not the end of your problem. You need speed and power to recover to a safe place. An incredibly tight turn followed by a stall into the trees below scores no style points. The reason you got here in the first place was terribly bad foresight or unexpected sink conditions. In either case, having an airplane that is in a solid flying envelope after the turn helps to offset the laundry emergency that accompanies these kinds of adventures.
TD
