Wisconsin - Sport Copter Vortex - Fatal - N634SC

[Gyro28866]

In the last 25 years, I have made a few downwind landings. A few were intended and a couple were deadstick. The technique I use is to fly a normal approach VERIFING my AIRSPEED and MAINTAINING sufficient AIRSPEED on the approach. As I roundout and start to settle on the ground. I use a really soft field technique. DO NOT let the visual picture screw with you, the touchdown speed is quite a bit higher than what you are used to; maintain airspeed - you are flying the rotor. As the mains touch I hold slightly nose wheel off the ground (barely) and as the machine slows, I increase the amount of rear stick movement, until I cannot feel the rotors influence, By then I am at full stick back position. I try to hold the nosewheel off as long as possible. The landing and roll out is significantly longer than what you are used to.
I have witnessed a few others make downwind landings and it appears that they want to fly based on ground speed and not airspeed and at some point at 5' - 10' of remaining altitude the machine drops out from under them. That would be because they did not maintain the airspeed to maintain rotor rpm. They started flying visually based on ground speed and because of the downwind condition, they allow the airspeed to get way too slow. You have to fly it on, at the absolute minimum airspeed as possible.
Airplanes and Gyroplanes are able to fly if they maintain AIRSPEED not groundspeed!!!

 

[thomasant]

Could you please elaborate...? That 'reversal of airflow' phenomenon is completely unknown to me...

Hi Xxavier,
I'm attaching the thread where this is discussed. Hope that helps.

What is drag over ?

full understanding of PPO and torque over but not sure what drag over is I have seen Doug mention it a few times. maybe I understand it by a different name. Is it when the frame rotates due to rotor drag eg rotor spins anti clockwise so with power off the friction in the head also pulls...

www.rotaryforum.com

Post 10 and 11 of above thread.

 

[thomasant]

Thomasant - So if you are accelerating on take off and need to push the stick slightly forward to increase airspeed there is something that prevents that on the gyro you mentioned?

The trim system actuator in that gyro was for 350 lbs. Impossible to push the stick forward if the trim is fully back for an average strength person during the take off roll.

 

[XXavier]

Hi Xxavier,
I'm attaching the thread where this is discussed. Hope that helps.

What is drag over ?

full understanding of PPO and torque over but not sure what drag over is I have seen Doug mention it a few times. maybe I understand it by a different name. Is it when the frame rotates due to rotor drag eg rotor spins anti clockwise so with power off the friction in the head also pulls...

www.rotaryforum.com

Post 10 and 11 of above thread.

Thanks... I understand now... You were pointing out the danger of losing rotor revs due to a lack of steady relative wind...
But that isn't (I believe) caused by a flow reversal. In fact, if you reverse the flow, a rotor still turns in steady autorotation. It can be observed if, after landing with a stiff wind, you turn your rotor back on the wind. It keeps turning quite well...

 

[Vance]

Thanks... I understand now... You were pointing out the danger of losing rotor revs due to a lack of steady relative wind...
But that isn't (I believe) caused by a flow reversal. In fact, if you reverse the flow, a rotor still turns in steady autorotation. It can be observed if, after landing with a stiff wind, you turn your rotor back on the wind. It keeps turning quite well...

It appears to me Doug and David are writing about a gyroplane rotor phenomenon having to do with a heavy rotor that is accelerated above normal flight rpm descending into its rotor downwash resulting in an inhibited ability to arrest the descent.

 

[Philbennett]

Good grief I've read some remarkable things but this thread is starting to trump them all. Just what on earth are people talking about? First of all how does a gyroplane rotor "over-speed" and reverse its flow?? Its just utter garbage. As for teaching / demo'ing downwind landings is idiocy. Just what possible value add could it be for a low time student pilot who if US students are anything like UK ones struggle to perfect into wind landings!

 

[Vance]

I feel there is value in teaching the skills to manage things that aren’t working out as expected.

That is why I practice and teach engine out emergency landings and downwind landings.

Engine out accurate landings are a required part of the practical test standards, downwind landings are not.

In my experience people; included me, don’t always know which way the wind is blowing when the engine stops making power.

In the areas I fly the wind is often blowing in a different direction five hundred or a thousand feet above the ground.

The wind direction can change on short final and going around is not an option when the engine is not making power.

Turning back to the runway and landing downwind may be the best option in an engine out on takeoff challenge.

I had a good friend turn back to the runway they had just taken off from landing downwind when they had a problem on takeoff with no good options in front of them. There were no injuries because this was the best thing to do and they had the skills to do it.

It is my observation that sometimes there is not a suitable landing zone ahead within gliding range.

The message I am trying to send to my clients is things don’t always work out as planned and there is value in being prepared with skill sets to manage these challenges.

A friend of mine recently had 912 engine out accident that in my opinion could have been a nonevent if he had practiced engine out emergency landings. He overshot the landing zone and hit trees. I wasn’t there so I don’t know that for a fact.

The fatal accident that this thread is about that appears to have resulted from an engine out and may have been avoided with a little more instruction. Once again I wasn’t there so I don’t know that for a fact.

 

[Vance]

Good grief I've read some remarkable things but this thread is starting to trump them all. Just what on earth are people talking about? First of all how does a gyroplane rotor "over-speed" and reverse its flow?? Its just utter garbage.

It is my observation that in a sixty degree bank the rotor rpm of The Predator increases to as much as 140% of straight and level flight rotor rpm not unlike a jump takeoff gyroplane.

It seems reasonable to me to imagine that heavy rotor blades when accelerated beyond flight rpm would briefly act as a powered rotor of a helicopter as they slowed back down.

I am proud to know Antony Thomas.

He is a retired Major from the Indian Army and flew high altitude rescues in the Himalaya Mountains flying Lama helicopters.

He has certificates for Commercial Helicopter, Instrument Helicopter, Advanced Ground Instructor, Sport Pilot Gyroplane, CFI Gyroplane.

In my opinion based on our discussions he knows a lot about rotor aerodynamics as does Doug Riley and David Bird.

I feel dismissing something they posted as “just utter garbage” will probably stop you from learning from them.

 

[thomasant]

Good grief I've read some remarkable things but this thread is starting to trump them all. Just what on earth are people talking about? First of all how does a gyroplane rotor "over-speed" and reverse its flow?? Its just utter garbage. As for teaching / demo'ing downwind landings is idiocy. Just what possible value add could it be for a low time student pilot who if US students are anything like UK ones struggle to perfect into wind landings!

Looks like you don't have a clue. Read the thread, and maybe you will get some idea. You might want to start another thread before this one becomes vitriolic.

 

[thomasant]

It is my observation that in a sixty degree bank the rotor rpm of The Predator increases to as much as 140% of straight and level flight rotor rpm not unlike a jump takeoff gyroplane.

It seems reasonable to me to imagine that heavy rotor blades when accelerated beyond flight rpm would briefly act as a powered rotor of a helicopter as they slowed back down.

I am proud to know Antony Thomas.

He is a retired Major from the Indian Army and flew high altitude rescues in the Himalaya Mountains flying Lama helicopters.

He has certificates for Commercial Helicopter, Instrument Helicopter, Advanced Ground Instructor, Sport Pilot Gyroplane, CFI Gyroplane.

In my opinion based on our discussions he knows a lot about rotor aerodynamics as does Doug Riley and David Bird.

I feel dismissing something they posted as “just utter garbage” will probably stop you from learning from them.

Thank you Vance. I truly appreciate your kind words.

I just don't get it that some are just content to be happy with just what they know. If bad things can happen to me with 3400 hours of time, and I am unable to deal with a situation that I had no knowledge of, then I feel sorry for those students that are not shown some skills that may help them some day. I find it hard to imagine in a downwind situation, climbing to pattern altitude to align into the wind when the engine goes quiet.

It is not my intent to get into any drawn out discussion with anyone else. Like you, I believe there is value in learning all that one can.

Some forget that learning is a lifelong process.

 

[XXavier]

Good grief I've read some remarkable things but this thread is starting to trump them all. Just what on earth are people talking about? First of all how does a gyroplane rotor "over-speed" and reverse its flow?? Its just utter garbage. As for teaching / demo'ing downwind landings is idiocy. Just what possible value add could it be for a low time student pilot who if US students are anything like UK ones struggle to perfect into wind landings!

It is my observation that in a sixty degree bank the rotor rpm of The Predator increases to as much as 140% of straight and level flight rotor rpm not unlike a jump takeoff gyroplane.

It seems reasonable to me to imagine that heavy rotor blades when accelerated beyond flight rpm would briefly act as a powered rotor of a helicopter as they slowed back down.

(...)
(...)

That sounds strange...

Let's see... You bank 60º, hence your load factor goes to 2 gs. In reaction, the rotor revs faster. Now, you go back to s/l, unaccelerated flight, and the rotor slows down, the extra energy stored there being converted into extra thrust. The gyro will then gain some altitude.

I doubt that the flow could be reversed, even for a very short time, but even if it did, I can't see how that could be a dangerous problem... It's all probably a misunderstanding...

 

[Philbennett]

Hang on. This has nothing to do with glib references to lifelong learning nor is it a personal attack on the individual. It is simply calling out things presented as fact without any proper reference or context. Remember the behind the power curve....? In the UK the CAA have even changed the gyroplane technical exam now to remove this nonsense that had been established for many decades. I digress.

So first of all downwind landing practice to students. It’s utterly rediculous because it’s dangerous and regardless of it being possible that misses the point. A student or low time pilot is mentally maxed out most of the time and so the safest process for them is to learn the basics well and without error.

Now to move on to this reverse flow and overspeed of rotors to allow some kind of special landing. First of all what does “overspeed” of rotors actually mean? Beyond the normal or beyond design limit? How is this “over speed” obtained? Then as has been said already any extra rotor RPM due to flight beyond normal g is transient. So when if you believe this concept of overspeed and reverse flow ( which I don’t) then I still don’t see how it helps.

If you are an instructor posting on this site you probably have a responsibility to the new guys and communicate things that will keep them safe.

Below is a video (posted by the pilot who also provides the commentary) how communicated gyroplane witchcraft is dangerous. I believe he was trying to add rotor rpm as is being stated in this thread. You can see the rotor RPM gauge and you can see by being distracted from a good but basic process allowed him to almost hit wires... fly like a gyroplane pilot.. you couldn’t make this nonsense up!

 

[thomasant]

Philbennet,
No pilot usually crashes and dies because they know what to do in a given situation. It is usually what they do not know of to deal with a situation that kills them.

If an instructor is sending a student pilot on their first solo, it is the instructor's responsibility to clear them after knowing that the student can handle unexpected situations. Some will rest at just the basic stuff and leave it at that. Others will demonstrate to the students what can happen in some unusual situations that could happen. Changes in winds from HW to DW are not unusual, happen all the time. I applaud instructors like Vance, who go the extra mile in their thoroughness to details.

Your lack of understanding about rotor over speed and its consequences is understandable. It is not part of any syllabus that I know of. Those that need a deeper understanding will seek out the material and do their own critical thinking. My personal responsibility as an instructor is to ensure that my student is prepared to deal with any situation that is out of the norm.

I remember this proverb, "He who knows not, and knows not that he knows not, is a fool... shun him. He who knows not, and knows that he knows not, is willing... teach him. He who knows, and knows not that he knows, is asleep... awaken him. He who knows, and knows that he knows, is wise... follow him."

You can keep making rude statements on this forum like you are the authority on gyroplanes. There are several before you, who IMHO have given a heck of a lot more insight on this forum than the stuff you are posting. I'll leave it at that.

 

[Philbennett]

Thomas - teach the forum. Please can I have a reference for the rotor overspeed / reverse flow from any recognised aeronautical source.

I'll leave it at that.

 

[MilesW]

In my opinion based on our discussions he knows a lot about rotor aerodynamics as does Doug Riley and David Bird.
I feel dismissing something they posted as “just utter garbage” will probably stop you from learning from them.

And if I recall correctly, David Bird's signature contained the line - "Ignorance is bliss ... but only till you realise you were". As an aside, while Birdy played the hick card, his knowledge of the aerodynamics of the gyro rotor is second too none. One of a handful on this planet that actually knows his sh%t. Lot's of pretenders.

Condemning the teaching of downwind landings shows a fairly high level of ignorance. Another sig that comes to mind goes along the lines of "you don't know what you don't know". ie Maybe the writers own experiences don't lend themselves to his seeing the need, but that doesn't mean the need doesn't exist.

Miles

 

[WaspAir]

Condemning the teaching of downwind landings shows a fairly high level of ignorance. Another sig that comes to mind goes along the lines of "you don't know what you don't know". ie Maybe the writers own experiences don't lend themselves to his seeing the need, but that doesn't mean the need doesn't exist.

You may be in the other camp on a philosophical difference of opinion, but that doesn't justify accusing dissenters of harboring "a high level of ignorance". There are a host of choices that must be made by instructors based on risk/benefit considerations. For example, I do not teach full-down autorotations in the R-22 to primary students, because the risk in training is extreme. Similarly, although there has always been much debate about it, the FAA abandoned spin recovery training requirements (favoring avoidance) for private pilots in airplanes decades ago because their stats showed it did more net harm than good. This dispute has comparable roots. I demo but do not teach downwind approaches, while teaching go-arounds, methods of determining wind direction, and constant evaluation of potential landing sites (wind considerations included). I consider a student who does downwind approaches to flat terrain in non-emergency situations to be exercising poor airmanship. My students are not training to muster cattle, or land at Lukla. I have made a fully informed choice, which differs from yours, but that disagreement does not establish ignorance on my part. Can we avoid the personal accusations?

 

[Philbennett]

Waspair sums it perfectly and as for the other theory at the very least the reference doesn’t seem to be at the finger tips.

It might be recognised that the video I posted gives a real example of how enacting some of this theory is dangerous, whilst a more basic technique would have afforded far greater safety margin.

Being more specific his “flying like a Gyrocopter pilot” gave no performance advantage in the way he expected as rotor RPM decayed to normal the instant he rolled straight and level as g returned to normal. Whilst the manoeuvres required to gain that g loading meant he was turning quite aggressively and distracted him from maintaining a good lookout earlier for wires.

Demoing/ promoting or experimenting with elements that aren’t standard syllabus items seems at the very least poor risk / reward because not only does it suppose a student might be able to retain the correct context but should it go subsequently wrong it doesn’t replay very well in the face of authority. FAA/NTSB “so what happened?” Accident pilot “my instructor was showing me/ told me that if I did / how I could do xyz....”

 

[Vance]

In my opinion Phil; the video you attached is unrelated to practicing downwind landings or any rotor theory presented by Doug, David or Antony so I don’t understand you point.

I agree that some the video does not conform to accepted rotor aerodynamics or my personal flying experience.

 

[Tyger]

I don't cotton to that S-turn business in the video - at all. Is that what you mean by "communicated gyroplane witchcraft", Phil?

 

[MilesW]

You may be in the other camp on a philosophical difference of opinion, but that doesn't justify accusing dissenters of harboring "a high level of ignorance". There are a host of choices that must be made by instructors based on risk/benefit considerations. For example, I do not teach full-down autorotations in the R-22 to primary students, because the risk in training is extreme. Similarly, although there has always been much debate about it, the FAA abandoned spin recovery training requirements (favoring avoidance) for private pilots in airplanes decades ago because their stats showed it did more net harm than good. This dispute has comparable roots. I demo but do not teach downwind approaches, while teaching go-arounds, methods of determining wind direction, and constant evaluation of potential landing sites (wind considerations included). I consider a student who does downwind approaches to flat terrain in non-emergency situations to be exercising poor airmanship. My students are not training to muster cattle, or land at Lukla. I have made a fully informed choice, which differs from yours, but that disagreement does not establish ignorance on my part. Can we avoid the personal accusations?

Please read again, slowly. I stated that condemning the teaching of downwind landings was ignorant. I did not say that disagreement about the practice was ignorant. I did not state my own position, but it is pleasing to see you acknowledge the downwind landing is a reality and by demoing it make your students at least aware of the possibility and then work on the tools that should make the need unlikely.