- Joined
- Oct 30, 2003
- Messages
- 18,377
- Location
- Santa Maria, California
- Aircraft
- Givens Predator
- Total Flight Time
- 2600+ in rotorcraft
Ferran posted on a thread with what I find to be a particularly annoying title “Engine out causing fatality?”
I am not familiar with many of the European gyroplanes accidents.
I feel it is important to understand these accidents.
I have observations from a distance.
Hello Ferran,
I feel you are too focused on low Gs.
In my opinion the low G event is usually very short in duration and it would be very hard to find a way to get to negative Gs.
On the other hand it is not that hard to stall a blade and they will slow down very fast if that happens.
I feel an unintended control input from an out of control fuselage is also a possible way to stall a rotor blade.
In the absence of lift it is not hard to imagine a descent rate that is enough to fold up the blades if they are missing the centripetal force of rotor RPM.
I feel that a stalled rotor blade can easily become a non recoverable event.
I don’t have enough data points to know which gyroplanes are falling out of the sky.
It is my impression that the Magni Gyroplanes are not falling out of the sky as much.
I hope if this is an incorrect impression someone will correct me. There are not enough Magni gyroplanes flying in the USA to get a statistical read on it.
It this is a correct impression it appears to me that the people who copied the Magni made a mistake that we should try to identify.
These copied gyroplanes seem to have a similar rotor system and divergent from Magni’s rotor system.
When I flew two different models from AutoGyro they both had a much more responsive rotor than any of the Magnis I have flown.
I found the Calidus needing rudder input with power changes and to a lesser degree the MTO Sport.
I did not notice this as much with the Magni.
The AutoGyro instructor I flew with seemed quite taken with slips as is another AutoGyro CFI that I have watched fly at several events. I am not a gyroplane slip enthusiast.
It is reasonable to expect that with the rapidly expanding market that putting the training infrastructure in place will take some time and mistakes will be made.
In my opinion any time there a lot of low time pilots flying around the accident rate will go up.
I feel that as more data points become available it will be easier to pinpoint the gyroplane models that have the most unexplained accidents. Perhaps the cause will immerge.
I cannot imagine what to do without sufficient data to even validate a hypothesis.
I expect as the financial stakes escalate so will the efforts to find and fix gyroplane challenges.
Thank you, Vance
I am not familiar with many of the European gyroplanes accidents.
I feel it is important to understand these accidents.
I have observations from a distance.
Gentlemen, I´ve been thinking a lot in the last months about gyrocopter accidents. I think that Europe´s gyrocopter accident record is really bad. And this is common to all countries with modern stable gyros. Anyway this is only my subjective opinion and I may be wrong...
From my point of view, if gyros are safer than planes, our fatal accident record should be much better... and this is not the case. I think (my subjective opinion again) that UK has the best safety record. And the main difference with other countries is the training requirements. In spite of this, their record is not good enough, it should be much better than fixed wing planes...
Have you seen the last accident reported in the forum? Have you seen that the blades are bended UPWARDS? The same that the last MT accident. The same that the Mallorca accident.
The main question is Why?
If the blades are bended upwards is because the lift force acting on the blade has done it. I think that the only possibility is a strong decay in rotor rpm… or maybe not so strong.
One of my friends who is an engineer has calculated that a drop of 10% in rotor rpm reduces 21% the centrifugal force acting on the blade. So a decay of only 30% in rotor rpm would produce a reduction of 63% of the acting centrifugal force…
Our teetering rotors cannot afford this lack of centrifugal force, and the result is a flexion force that bends the rotor blades upwards. I believe that this is the substitute of PPO on modern gyros…
This can explain a lot of badly explained accidents that has happened lastly. My main concern is that we don´t know nothing about how long can be unloaded a rotor before that rotor rpm decay will be lethal. I think that this is a very important issue that has not been analyzed in our certification rules (BCAR T).
I guess that time elapsed before that the rotor rpm has decayed too much is closed to 1 second, and less than two seconds… Of course I can be wrong, but this is something we should study in a wind tunnel (real flight is too dangerous)
The teetering rotor cannot work against flexion. Its individual blade flapping freedom is 0.
An average C-30 had a flapping freedom from -10 to +40º. This is a big difference. Most probably this is the difference between a safe gyro and our wonderful modern stable ones…
Did you know that the average rotor speed of a C-30 was about 200 rpm? I don´t know of a single C-30 accident because of unloaded rotors.
I know that we can fly a gyro with a teetering rotor for ages without any problem. But if you unload significantly the rotor you will be dead. And I believe that the gyro community is not aware of that.
What do you think?
Ferràn
Hello Ferran,
I feel you are too focused on low Gs.
In my opinion the low G event is usually very short in duration and it would be very hard to find a way to get to negative Gs.
On the other hand it is not that hard to stall a blade and they will slow down very fast if that happens.
I feel an unintended control input from an out of control fuselage is also a possible way to stall a rotor blade.
In the absence of lift it is not hard to imagine a descent rate that is enough to fold up the blades if they are missing the centripetal force of rotor RPM.
I feel that a stalled rotor blade can easily become a non recoverable event.
I don’t have enough data points to know which gyroplanes are falling out of the sky.
It is my impression that the Magni Gyroplanes are not falling out of the sky as much.
I hope if this is an incorrect impression someone will correct me. There are not enough Magni gyroplanes flying in the USA to get a statistical read on it.
It this is a correct impression it appears to me that the people who copied the Magni made a mistake that we should try to identify.
These copied gyroplanes seem to have a similar rotor system and divergent from Magni’s rotor system.
When I flew two different models from AutoGyro they both had a much more responsive rotor than any of the Magnis I have flown.
I found the Calidus needing rudder input with power changes and to a lesser degree the MTO Sport.
I did not notice this as much with the Magni.
The AutoGyro instructor I flew with seemed quite taken with slips as is another AutoGyro CFI that I have watched fly at several events. I am not a gyroplane slip enthusiast.
It is reasonable to expect that with the rapidly expanding market that putting the training infrastructure in place will take some time and mistakes will be made.
In my opinion any time there a lot of low time pilots flying around the accident rate will go up.
I feel that as more data points become available it will be easier to pinpoint the gyroplane models that have the most unexplained accidents. Perhaps the cause will immerge.
I cannot imagine what to do without sufficient data to even validate a hypothesis.
I expect as the financial stakes escalate so will the efforts to find and fix gyroplane challenges.
Thank you, Vance