Starting to read tonight. Recommended by several pilots. Comments welcome.
https://amzn.to/3Fxrqa4

Give us a review when you're done reading.

https://amzn.to/3vUHO12

I like this one.

G44 wrote:https://amzn.to/3vUHO12

I like this one.

Definitely will add to my reading list! Thank you for link.

I wonder if any of the traps are also shared with fixed wing or are they just for helicopters?

175 magnum wrote:I wonder if any of the traps are also shared with fixed wing or are they just for helicopters?

So far in my first few pages, Greg Whyte freely admits that everything written in his book is also written elsewhere. The book, goes on to, examine (more deeply) the cause and effects of accidents. Centered around the chain of events, one can deduce the common components such as stress, maintenance, complacency etc...

There are a lot of “cut and pastes” from NTSB style reports. Which serves to remind, that anyone can look up an accident and get facts relating to safety, if not for just helicopters.

I don’t think I would specifically recommend the book to non rotor pilots, even though Mr. Whyte does. Most discussions appear to reflect the absolute cause such as LTE, Vortex Ring State, over pitching etc...But, in a strict aerodynamic sense would fit into any heavier than air craft. But, reading certainly brings interesting facts to all.

Glad to have you onboard this thread, never stop learning and striving for safety!

I am on page 68 and I agree. It is heavily helicopter aerodynamics and a bit too much math for me. I would have liked a bit more comparison with airplane. He is a research and data type writer like my wife. I am more opinion supported by experience and other data, but my wife also questions my bias. His data, for instance, covers how much more important wind management is in helicopters. He does not express this opinion, however. A light tailwind which would be almost no factor in airplane operations could become significant at helicopter ground speed. In helicopters, because airspeed can be so well controlled, we almost always have the option to manage wind to our advantage and safety. Don't let passenger comfort in the walk to and from the helicopter dictate how you are going to manage wind direction. It is no fun to have to back up to come out of a hover hole with a tailwind, and certainly not safe. Crew availability makes helicopter operations much, much safer. Crew can hike the passengers to where they need to be.

G44 wrote:https://amzn.to/3vUHO12

I like this one.

FYI, unfortunately Shawn passed away last week. https://www.pprune.org/rotorheads/641263-shawn-coyle-rip.html

"Impressive" only begins to describe the gentleman.

pat

175 magnum wrote:I wonder if any of the traps are also shared with fixed wing or are they just for helicopters?

This: "All rivers have wires."

Oh noooooo! He was such a wealth of information. I really like his books.

Kurt

The autorotation coverage is way above my math ability, but he does go into technique a bit more which is helpful. We didn't get this deep into helicopter aerodynamics in Army flight school, but we gots lots of experience and especially practice doing autorotations. He gets into how to increase glide range quite a bit. We learned to look between the pedals and expect to go near that spot. Getting oriented into the wind before flair and basing initial pitch on weight and rotor blade size was really important, as he points out. Thin and light rotor helicopters like the Houghs 269 (TH-55) autorotate more like a Cub three point pitch attitude speed reduction and then wheel landing than a Huey autorotation. There may not be enough rotor inertia for initial pitch pull to reduce rate of descent so it becomes just the continuous pitch pull at very low altitude. The Cobra MR blade is so heavy, on the other hand, that it can be landed in autorotation much like landing an airplane using a power/pitch short final to touchdown. Power (inertia) is a one shot deal, however, but still longer than light rotors. Getting onto the surface with the skids level is critical in any helicopter. And if there is forward speed, longitudinal alignment is as important as with the Cub.

Because of the economically efficient kind of work helicopters mostly do, things that cannot be done with a much cheaper to operate airplane, most actual autorotations will be hovering (IGE or OGE) autorotations. Concerning the dead man's curve, however, airspeed is altitude same as in the airplane. In Vietnam we learned that way too fast approaches limited exposure to enemy gunfire and provided a possible zoom to where they were not if they got the engine. Yes, in normal helicopter work, airspeed is usually not available.

iPat wrote:

175 magnum wrote:I wonder if any of the traps are also shared with fixed wing or are they just for helicopters?

This: "All rivers have wires."

I forked this thread into the general forum to include all low flying aircraft:
https://backcountrypilot.org/forum/wires-danger-in-the-backcountry-forked-thread-25202

When he gets to tail rotor problems, the math is a bit more understandable. The main rotor turns one way and the body attempts to turn equal and opposite save for a little dampening during hover and relative wind streamlining in forward flight. The single main rotor helicopter is continually trying to upset itself. To compare to the airplane, we are obliged to dynamically and proactively walk the anti-torque pedals continuously and not just on short final, touchdown, and roll out as in a tailwheel airplane. Helicopter is safest as a two pilot aircraft because the attention to detail is tiring. It eventually causes vertigo in IMC. Unlike the airplane, we can't just let her have her head and she will do amazingly safe things like always lower her nose in a turn. Let her have her head and she will go wild. We scratch our nose with the collective hand, not the cyclic hand. I did it the other way over Possum Kingdom in a Th-55 and it pitched straight down.

He spends a lot of time with vortex ring in both main rotor and tail rotor. Mainly we just need to attend continually to dynamic proactive control in order to never let loss of control issues develop. Anytime vortex ring, either main or tail rotor, could become an issue (slow or hover with tailwind or left side crosswind in US helicopters) we need to continually bracket tip path plane control with cyclic and anti-torque control with pedals. If we are already correcting when the situation presents itself, we will do fine. If overthinking it cause us to tense up, that is not good. It is not a do this sort of technique. It is dynamic and waiting to react may be too late.

The collective, while also moved dynamically in a hover can be more reactive as climb or descent is slower than flaying about. Boeing did an amazing job with the CH-47 Chinook. There is a trigger on the collective which has to be pulled to move it. Once that trigger spring is released, it will maintain that hover altitude exactly until it runs out of fuel. I'm not an engineer but I think it is both that the two main rotors turn opposite each other and that the tail moves up and down dynamically and within a tight envelope constantly in hover. It is much like the pitch up pitch down oscillation of a Cessna in a full flap rudder to the stop side slip. Boeing is stabilizing hover altitude and Cessna is stabilizing average glide angle.

Finally have a quiet moment to continue reading...

Chapter 2, Page 32 Vortex Ring State:

Due to the book’s majority of editing being done 20-30 years ago, the “Vuichard Method” is not discussed. But, that’s OK, it’s a pretty new technique for recovery. Please watch Vuichard video, definitely revolutionized low level helicopter flying.

Claude Vuichard:

Pilots have always been trained to recover from the vortex ring state by lowering the collective and pushing forward on the cyclic. The problem is that due to the tailwind, they are following their vortex ring — and the ground usually meets them before they leave the vortex ring state! Reasoning that the tail rotor continues to work normally in the vortex ring state, I thought I could use it to help me reach the upwind part of the vortex to the side of the aircraft. If I then supported this with cyclic, the helicopter would reach the upwind part of the vortex very fast. As a flight instructor, I resolved to put the helicopter into a vortex and put the technique to the test.

Reference Page (46) chapter (3) Recirculation:

Does anyone have firsthand knowledge with Fig. 3.1?



Looks to me like an IGE hover over a flat hard surface which immediately intersects a vertical wall would enhance the ground effect not deteriorate the effects? I might try an IGE hover and record manifold pressure (MP) next to and then away from a large vertical hangar. Then compare which is greater.

Note: The recirculating air is not depicted on the right side of the drawing. Fig 3.1 shows the air moving horizontally, instead of returning to the rotor disc. Proof reading error?

I had no problem landing on the 13th floor helipad of the 16 story Loma Linda Hospital in LA. I did fuss about flying a medevac Huey in a window, but their radio operator didn't get the joke. She never used the word helipad, just 13th floor of a 16 story building repeatedly , even after my joke. Lots of hospital helipads are on a lower step of a building with different levels. That would be with both clockwise and counterclockwise rotors. So I agree, helps as much as hurts.

Concerning turning rotors near buildings and people: A blade strike can make a field goal from anywhere on the field....and take out several in both team's crowd at the same time. It's not rotor RPM, it's the tip speed. Debree field of an airplane crash is unidirectional, but blade strike impacts all in the area.

175 magnum wrote:I wonder if any of the traps are also shared with fixed wing or are they just for helicopters?

Don't fly into IMC if you are not rated and ready. (Kobe)

There have been some tail booms chopped off by the main rotor in several single rotor helicopters lately. I hope we are not over practicing rolling out or vortex ring state or what we called settling with power in the Army. We pitched the tip path plane down to fly out, but I have no particular problem with the roll out method. Whatever is practiced should be an immediate recovery technique without loosing control such that the main rotor is disturbed enough to flex down into the tail boom. I didn't do much long line work, but outside that we had no need of settling with power other than when going into a high DA landing zone very slow without moving the collective. Bringing power in to stop forward movement and descent was causing the military to lose tail rotor control and spin in the landing zone. The Army Mountain Flying Course at Ft. Carson found a way to prevent that with a very slow approach with the power that would be needed in the LZ to hover in ground effect already set. At zero airspeed on the ASI on short final, we used the very beginning of settling with power to go down on the glide angle and just pitch with cyclic forward a bit to go up on glide angle by getting a bit less settling.

This technique was very smooth and stable, certainly not well into the vortex ring, and it was very near the terrain. Long line, hovering well out of ground effect, bothered me a lot. There, we were not near terrain (long way to fall) and pitching down to fly out of the vortex ring would require dumping the load on the long line.

We use the same settling with power, mushing, technique when we decelerate on short final coming into ground effect in airplanes. Unless we slow well below Vso, we will stay stabilized on a glide slope that will overfly the desired touchdown spot. By pitching up to settle with full flaps and power, mushing, we bring the throttle dynamically into play and make the power pitch approach to the desired spot workable. Increasing power near or at the bottom doesn't overtax the anti-torque ability of tail rotor in airplanes as with helicopters at high DA, however.

We don't have a lot of helicopter pilots on here, but we don't want to lose any. Don't practice the vortex ring state technique to the point of loss of control. The onset of settling with power is smooth and similar to the mush well before stall in fixed wing. As slow as practicable is the safest way to approach in airplane or helicopter and mild mushing or settling with power can be used effectively on the approach.

Airplanes, with dynamic neutral stability, don't have to be acrobatic to safely be stalled or spun or even out of control for a bit. Helicopters will destroy themselves when allowed to go out of control a bit. You can't even scratch your nose with the cyclic hand. Don't try a settling with power recovery technique that allows the helicopter to fall. Don't zero the airspeed with a tailwind. Even when we have to start an approach downwind, we can come about before zeroing the airspeed. Wind management is critical. Dropping or picking up a troop from a hover can be accomplished parallel to a ridge with the tip path plane tipped into the crosswind component. The same with working next to buildings or landing on the medevac helipad of a hospital.