bent prop H

[AH-1G]

Hover, stationary no moving x y z axis.

How Helicopters Work

Believe it or not, the marvel we know as the helicopter began as a Chinese top consisting of a shaft — a stick — adorned with feathers on one end.

science.howstuffworks.com

 

[Eagle's Eye Video]

Sorry didn't know the rule of not posting telemetry, no other relation with pilot that a facebook pal. I wanted to know what happened to this chap, in order to learn.

I'm sorry but you are missing the entire point... this "chap" needs to come on this board and communicate with this collective community directly, not through any other people... including yourself.

As far as all the speculation of what happened... this entire incident is completely pilot error... it started with purchasing 3rd party components, on something both so inexpensive and yet crucial to the entire operation of the aircraft. Everything else that happened after that point, can be directly attributed to that single decision.

 

[PatR]

Don’t close it as there’s some good discussion relative to defining hovering flight. It may come as a surprise to some that a multirotor is almost never in equilibrium while in a stationary hover. And that a perfectly stationary hover is virtually impossible.

Regardless of correct or incorrect, the positions taken in this latter part of the thread are both educational and entertaining.

 

[Eagle's Eye Video]

Don’t close it as there’s some good discussion relative to defining hovering flight. It may come as a surprise to some that a multirotor is almost never in equilibrium while in a stationary hover. And that a perfectly stationary hover is virtually impossible.

Regardless of correct or incorrect, the positions taken in this latter part of the thread are both educational and entertaining.

I will let others make the decision to lock... I agree both in the educational and entertainment value...but essentially you clearly quantified the discussion with the post above... there is hovering only... period. With technology, comes the capability of reducing the constantly changing variances, below our senses ability to detect those changes. But that level is far above any high end consumer / prosumer product that is sold by Yuneec.

 

[PatR]

But that level is far above any high end consumer / prosumer product that is sold by Yuneec.

Ya know you just burst a few bubbles, right?[emoji3166]

 

[Eagle's Eye Video]

Yeah, I know... that whole common sense thing... has it not occurred to anyone that if the flying platform were that rock solid, that we would have no need for uhhhh, stabilized gimbals and such?

 

[PatR]

Indirectly why I hoped you would leave the thread open, to motivate people into thinking about how a multirotor flies and what is involved when it is maneuvered or placed in a hover.

There are many aerodynamic and thrust forces involved in every aspect of a multirotor flight and the computational efforts required to keep everything in balance are incredible, especially considering how small the device is that accomplishes those tasks.

When we consider the marriage that exists between the battery, FC, ESC’s, and motors, and how each must function for the others to perform correctly, we should be in awe. But first we need to understand what and how they do what they do.

 

[Eagle's Eye Video]

Education is always good... ?

the marriage that exists between the battery, FC, ESC’s, and motors, and how each must function for the others to perform correctly, we should be in awe.

Thrust! Drag! Lift! Gravity! vs. LiPo! FC! ESCs! Motors!

Sounds like a Weekly World News headline if I ever read one...? or a porn title... can't decide ?

 

[DCH]

Thrust! Drag! Lift! Gravity! ....
Sounds like a ... porn title... can't decide

I think I saw that one! Isn't that the one with Stormy Daniels staring in it? ?

 

[Deleted member 6299]

I think I saw that one! Isn't that the one with Stormy Daniels staring in it? ?

”Home alone” + a guest. ?

 

[PatR]

Sounds like a Weekly World News headline if I ever read one...[emoji89] or a porn title... can't decide [emoji2955]

For anyone delving into physics, the engineering fields of electrical, mechanical, aeronautical, and other math sciences, or those simply enamored with flight, it’s closer to porn[emoji6]

When we have the basic understanding of how they work those that do have far fewer problems with them than those that don’t. Minor issues don’t become incidents because that understanding permits appropriate corrective action, or awareness of areas where minor design deficiencies can be offset by avoiding actions or conditions that could induce demonstration of a flaw.

Two things I believe to be the difference between a really good multirotor operator and an “average” one. Understanding the fundamentals of flight and performing a design/build of at least one multirotor from start through finished flight. In that process we learn that many “simple” questions about performance are anything but simple.

One other qualifier is a history with RC flight before the introduction of auto pilots and wing levelers, but such people are not as drawn to multirotors as those born after 1980-1990. There was a cultural shift away from manual accomplishments that was great for automation but inhibited deep understanding.

 

[arruntus]

I'm not going to put a video here of the last hexacopter I'm building, that after making the autotune, you can see how it makes a perfect stationary flight, a perfect hovering. Not to leave bad to Yuneec, otherwise I taught it to you ?

 

[PatR]

Stability is all about PID tuning and the quality of all the components in the flight system. Totally agree Yuneec could do a lot better with what they have in their systems. To do that would require that either they want to or understood them better.

Another factor that causes them a few headaches is trying to provide an aircraft with a bit more agility than average while trying to still keep it stable enough for ham handed operators and beginners. In a way they do that by slowing the system response down through GPS and Smart mode while tossing Rabbit and Turtle speed adjustment into the mix. In theory a great idea but for the system to be agile the PID tuning has to be set up for a relatively fast response, so the system remains a little quirky to initial stick response even at slow speeds. Some don’t understand that’s not a stability issue but one relative to command response. Understanding and use of exponential in combination with rate switching would resolve this and would allow the user to customize to their taste but the ST-16 programming does not provide for effective mixing in those areas. As so many don’t understand the concepts and have demonstrated they will enter the system and start changing things without any understanding the effects of what they are doing it may well be the way Yuneec set up the ST-16 was a good thing as it limits the extent of how badly a user can mess things up.

As you know, the basic Pixhawk FC has an auto tune feature that does a pretty darn good job of tuning PID’s, but Yuneec either removed that feature or blocked access to it with the Typhoon H. In fact, there is a great deal more a basic Pixhawk FC provides that is not present in the Typhoon H’s version of Pixhawk. What they did to the Pixhawk is comparable to taking a winning thoroughbred and sending it to the slaughter house.

 

[PatR]

Perhaps also related to money. How much spent in developing something that provides the best money in profit. Spend enough money and we can do most anything, but there remains questions if what was spent was worth it and how much people would spend to have it themselves. The average buyer has self imposed spending limits while thinking everything they want or need should fall within that level of affordability.

 

[Fred Garvin]

....The average buyer has self imposed spending limits while thinking everything they want or need should fall within that level of affordability......

80% of my Photography customers.

 

[DronAirPro]

Hi to all,

it as been a long time (too long) since I came on this forum.
I just saw this topic and as it is talking about me...
Yes I am the one to whom this incident happened.

I will just give the facts and no certitude as I haven't any, only possibilities:

My Typhoon H isn't new but never had crash before, even if it happened to land in high grass or in brambles twice. This was months before, I checked it after this and it then flew many hours without problem.
I check very cautiously my drone before and after every flight, that doesn't mean that I couldn't miss something wrong but I am very demanding about security!
One thing is that I bought some propellers, thinking they were original ones (I always buy original propellers) and made the mistake, yes I make some, not to verify this properly, so I flew with these non-Yuneec props.

So now, what happened:

- 3rd flight of the day:

No noticeable problem, during the shooting of a nice ancient tower near Fontainebleau (south of Paris).
Then I did a back tracking away from the tower, increasing altitude at the same time and ended with a stationary flight, until then, everything went smooth.
But then, here began the story. After a few seconds of stationary flying I eared a quite strong noise of flap, so in seconds I began to bring back home the H.
While doing this I eared a strong noise and distinctly saw an arm breaking, the H began, of course, to go mad and to fall.
Other arms broke very shortly after the first one (I couldn't say which one was the first unfortunately) and the H fell twisting to the ground where it crashed quite hard.

These are the facts !
You could see in a comment above the picture of a bend propeller with a motor and a small piece of a broken arm.
I honestly don't know if this propeller bent during the flight or when it crashed on the ground and I am surprised that a prop could bend like this and not break but it isn't because I never saw this that it can't happen. Here is the proof.

One of my thinking was that a prop (maybe this one) bent or broke in flight, causing strong vibrations that broke the arm. This arm was still attached by the wires and went to break other props and arms. This is only a possibility but...

Contrary to what has been said by someone in a comment above, I never meant this was the only real scenario.
I am open to any constructive, detailed and explained advice. I would thank anybody could help.

I must say that during this flight I didn't make any mistakes, it happens I make some and more likely I'll make some again but not this time.
I always had my H in direct view, was far above all trees or obstacles and didn't hit anything I could see (some told me, maybe a bird but in such case I really didn't see it).
I never lost connection with the drone, battery was fully charged and still (controlled) at about 50% after the crash.

Sorry for this long post but it had to be detailed.
Once again thanks to anybody could help and good and safe flights to all.

 

[AH-1G]

@DronAirPro , welcome back.
A very unfortunate event.
@Ty Pilot and I spoke over the phone discussing your event, and our focus was the propeller.
Are you able to bend back that propeller as straight as possible, can you give us the results?
In other words does it bend back without breaking?

 

[DronAirPro]

@AH-1G , thanks for your "welcome back"
Yes I managed to straighten the prop back again (still some small "waves" where it was bent and a very very small crack near the blade attach but not bigger than before I brought the prop back straight again).
So, yes, it bent back without breaking, that is why I thought that this very bad quality but well imitated prop could be the cause of the problem, even if not sure at all.
Once again, it was MY mistake, I always buy original ones and I thought these were but I didn't check enough !!!

 

[AH-1G]

Ok, good.
We surmised that during the extrusion process of manufacturing this and other blades were defective. Leaving a weak spot during the extrusion process.
You need X amount of catalyst to strengthen the blade properly while mixing during extrusion.

 

[DronAirPro]

@AH-1G here is the picture of the prop before and after straighten back.
The color of sticker is different because of the light but it is the same prop.