Thought Id ask a opinion


So sea level airport, no major obstacles, R44

One approach to landing, slowing to around 40, 60’ or so AGL, slowing more to a normal, to semi steep, approach

Second guy, comes in low level once over the airport grounds, with a good bit more speed, to a gentle slow quick stop, pull a little power (below cruise settings) and touch down.

Second guy has done too many combat assaults. Unless we have a stuck rudder pedal or are being shot at, there is no reason to hurry. If the second guy comes from Vietnam to a stateside National Guard Medevac unit, he will have to have his head space adjusted. Helicopters have the advantage of landing at zero ground speed. At that speed much less tin and skin gets bent. And hovering autorotation is not so bad.

The advantage of the steep and very slow (like shaking slow) approach is that time is available to see everything down there like stumps and wires, etc. 60 is OK to start but by keeping the touchdown spot appearing to close at a brisk walk, we can stabilize deceleration to zero ground speed for touchdown. OK, sometimes stuff shows up on the airport as well. Especially moving things can be dangerous. Night, for sure shaking slow. If low enough to hit a 100' tree we should be slow enough to hit a 100' tree and back out. 8GCBC does a really good job of flying around like an old man. That is the safe way to fly helicopters near the ground.

There is no gentle quick stop. Very fast and the quick stop has to pitch about the tail rotor, not about the center of gravity. That is hard on all the moving parts. And a lot of power is required.

First guy slows down into the H-V diagram avoid region, while the second guy stays underneath it, keeping himself in a better position should the engine quit on short final.

That being said, for reasons contact mentioned, I’ve flown most of my approaches inside the HV diagram because the risk of damage from hitting something not seen (usually due to blowing dust) was higher than the risk of an engine failure.

contactflying wrote:There is no gentle quick stop. Very fast and the quick stop has to pitch about the tail rotor, not about the center of gravity. That is hard on all the moving parts. And a lot of power is required.

Just curious, how is more power required to do what amounts of a power assisted auto rotation, compared to a semi steep approach?

fredy wrote:

First guy slows down into the H-V diagram avoid region, while the second guy stays underneath it, keeping himself in a better position should the engine quit on short final.

That being said, for reasons contact mentioned, I’ve flown most of my approaches inside the HV diagram because the risk of damage from hitting something not seen (usually due to blowing dust) was higher than the risk of an engine failure.

That was my thinking, and my initial thought was if it’s in a controlled and known environment (like behind the fence at a familiar airport, or over a clear taxiway etc) the low and fast route makes more sense.

If in a off field, or new to the pilot location, the more traditional normal to steep approach makes more sense.

The faster we are going before the quick stop maneuver, the more power required to decelerate without settling onto the tail rotor. That kind of mission requires a bottomless budget. Like changing heads every 50 hours.

Small helicopters with light main rotors come down very fast in autorotation. The one shot at the bottom has to be near the bottom. Yes, relative wind over the tip path plane (the big round wing) helps get down easy same as an airplane. With airplanes there are more loss of control (rudder to maintain longitudinal axis alignment) the higher the touchdown airspeed. No real need to go there in a helicopter. No need to go too fast in an airplane either, but that is another story.

Hovering autorotations need to be practiced starting from low hover and move up to higher. The normal autorotation with forward airspeed needs to be like a three point airplane landing until just before touchdown and then level the skids. My old crop duster instructor at Walters in the TH-55 had me nailed. He would wait until I was about to hit the stinger and then yell, "Wheel landing!" Again, this is the proper way to wheel land an airplane as well.

The bad high speed approach evolved out of Vietnam. The Huey (slick) hauling troops would approach the LZ at treetop level and 100 kts. From the Cobra above, I would call flair. They wouldn't see the LZ until coming down in a 45 degree pitch up flair and then level the skids for the troops to get out without touching down. In no way was it an autorotation. It took a lot of power all the way down. And a head change in 50 hours.

contactflying wrote:The faster we are going before the quick stop maneuver, the more power required to decelerate without settling onto the tail rotor. That kind of mission requires a bottomless budget. Like changing heads every 50 hours.

Small helicopters with light main rotors come down very fast in autorotation. The one shot at the bottom has to be near the bottom. Yes, relative wind over the tip path plane (the big round wing) helps get down easy same as an airplane. With airplanes there are more loss of control (rudder to maintain longitudinal axis alignment) the higher the touchdown airspeed. No real need to go there in a helicopter. No need to go too fast in an airplane either, but that is another story.

Hovering autorotations need to be practiced starting from low hover and move up to higher. The normal autorotation with forward airspeed needs to be like a three point airplane landing until just before touchdown and then level the skids. My old crop duster instructor at Walters in the TH-55 had me nailed. He would wait until I was about to hit the stinger and then yell, "Wheel landing!" Again, this is the proper way to wheel land an airplane as well.

The bad high speed approach evolved out of Vietnam. The Huey (slick) hauling troops would approach the LZ at treetop level and 100 kts. From the Cobra above, I would call flair. They wouldn't see the LZ until coming down in a 45 degree pitch up flair and then level the skids for the troops to get out without touching down. In no way was it an autorotation. It took a lot of power all the way down. And a head change in 50 hours.

What about bleeding that speed off with collective low and a progressive aft cyclic? I’m not talking 45 nose up and digging her heels in here.

The only time power is added is when the nose of the ship is pushed back level, that’s maybe pulling 22” on a day where 22.9” is max continuous

A soft field deceleration in low ground effect type landing is entirely possible in the helicopter. Stuck pedal or hydraulics failure running landing comes to mind. Otherwise, why? Nor is fast hover taxi really safe. The basic low ground effect takeoff is as useful as in the airplane, however.



















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contactflying wrote:A soft field deceleration in low ground effect type landing is entirely possible in the helicopter. Stuck pedal or hydraulics failure running landing comes to mind. Otherwise, why? Nor is fast hover taxi really safe. The basic low ground effect takeoff is as useful as in the airplane, however.




t

Avoids areas of operation per the AFM that it recommends to be avoided, less load on the engine, more fun?

Again I’m all for learning, hence the question.

But in a controlled area, like over a taxiway, seems a better way bring it in?

I agree, a off airport and or unfamiliar, a normal to steep approach all day long.

As we move forward gaining some relative wind to streamline the fuselage, we can relax a bit on the dynamic proactive anti-torque pedal movement for longitudinal axis alignment. We will never get the dynamic neutral stability of the airplane, but the helicopter can be controlled more like an airplane at airspeed. As we decelerate by maintaining the apparent brisk walk rate of closure approach, we increasingly become more helicopter than airplane. Wherever we slip off the airspeed over altitude chart, control becomes more dynamic proactive in pitch, roll, and yaw control. Approach to the ground is easier than approach to a three feet hover because we stay airplane like a bit longer. Either approach is safer than the fast approach and then quick stop, however.

A major safety feature of the helicopter is that the very unsafe late go around is avoided by deceleration to zero at three feet hover or the touchdown spot. We avoid late go around problems by being slow enough to maneuver and land elsewhere on the same airport. We throw that away with the fast approach. Helicopters are tremendously more dangerous than airplanes when they crash. Actually, crash is not necessary to kill people. Blade strike can send missiles a hundred yards in every direction. Near obstructions, including gas pumps, helicopters need to be treated like loaded guns. Tower wants to hear gear down and weapons cold, but the helicopter is the weapon. We are flying a grenade with the pin removed and it can't be stuck back in. If anything hooks a skid, especially with cross or tail wind, it is going over and it will beat itself into an unrecognizable piece of junk.

contactflying wrote:As we move forward gaining some relative wind to streamline the fuselage, we can relax a bit on the dynamic proactive anti-torque pedal movement for longitudinal axis alignment. We will never get the dynamic neutral stability of the airplane, but the helicopter can be controlled more like an airplane at airspeed. As we decelerate by maintaining the apparent brisk walk rate of closure approach, we increasingly become more helicopter than airplane. Wherever we slip off the airspeed over altitude chart, control becomes more dynamic proactive in pitch, roll, and yaw control. Approach to the ground is easier than approach to a three feet hover because we stay airplane like a bit longer. Either approach is safer than the fast approach and then quick stop, however.

A major safety feature of the helicopter is that the very unsafe late go around is avoided by deceleration to zero at three feet hover or the touchdown spot. We avoid late go around problems by being slow enough to maneuver and land elsewhere on the same airport. We throw that away with the fast approach. Helicopters are tremendously more dangerous than airplanes when they crash. Actually, crash is not necessary to kill people. Blade strike can send missiles a hundred yards in every direction. Near obstructions, including gas pumps, helicopters need to be treated like loaded guns. Tower wants to hear gear down and weapons cold, but the helicopter is the weapon. We are flying a grenade with the pin removed and it can't be stuck back in. If anything hooks a skid, especially with cross or tail wind, it is going over and it will beat itself into an unrecognizable piece of junk.

I get that, so in this case if landing at a airport, and shooting your approach over a taxi way, runway, etc, in a more or less sterile environment, wouldn’t it be prudent to keep the speed till you’re say 10’ and well in ground effect, high enough to not snag a taxiway light, below the avoid curve, would that be good?

Also interested in the wear on the heads with what I mentioned vs the shacking steep approach?

Yes, that approach would work fine. It is the g loading on the head that hurts. Real combat cowboy stuff. Getting shot at is the only thing that justifies that kind of abuse. The same abuse of the Cobra was not as acceptable. Only when the loach took fire was a rapid 120 degree bank roll in necessary. The nose had to go down significantly and at near 190 knots, the pull out was abusive. The rapid bank caused a shorter cycle whap whap that got Charlie's head down because he knew you were rolling in. Covering combat assault was more like a normal crop dusting and not nearly as damaging.

John Wooden, the famous UCLA basketball coach, explained good man to man defense as, "be quick, but not hurried." That works well for flying helicopters as well.

contactflying wrote:Yes, that approach would work fine. It is the g loading on the head that hurts. Real combat cowboy stuff. Getting shot at is the only thing that justifies that kind of abuse. The same abuse of the Cobra was not as acceptable. Only when the loach took fire was a rapid 120 degree bank roll in necessary. The nose had to go down significantly and at near 190 knots, the pull out was abusive. The rapid bank caused a shorter cycle whap whap that got Charlie's head down because he knew you were rolling in. Covering combat assault was more like a normal crop dusting and not nearly as damaging.

John Wooden, the famous UCLA basketball coach, explained good man to man defense as, "be quick, but not hurried." That works well for flying helicopters as well.

So keeping it 1G, maybe 1.3 max, would be ok?

BTW digging the UCLA quote