HELICOPTER GROUND RESONANCE : Understanding this dangerous phenomenon.
To be a good helicopter pilot and to avoid accidents, you need to know the hazardous flight conditions well. This is the second video in the series of "Hazardous Helicopter Flight Conditions". We study the Helicopter Ground Resonance.
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Links to demonstrations in full (Thank you to the providers) :
Video ground resonance : • Explained: AS350 Euroc...
Wobbly spinning top : • ForeverSpin Spinning T...
Swing exercise : • Resonant frequency of ...
Washing machine : • New Maytag Washing Mac...
Deathlock : • Helicopter Ground Reso...
Other videos in this series cover :
Vortex Ring State
LTE (Loss of Tail Rotor Effectiveness)
Mast Bumping
Dynamic and Static Rollover
Carburetor Icing
Rotor Stall
0:00 intro
0:38 Ground Resonance
1:58 Causes
3:29 Dangers
3:46 Triggers
6:04 Avoiding GR
6:47 Action Required
7:18 Real Case Example
7:52 Conclusion
8:12 Outro
Пікірлер: 80
Through, informative, concise, and - entertaining. 👍😎👍
@flyhighytb
Ай бұрын
Glad you enjoyed it!
The gazelle on the roof top was a very early version with the rigid type of landing gear. From s/n 1077 and higher, all gazelles had the flexible gear. The rigid gear was never a problem but the pilot had to position a handle to the rear for landing and fwd for flight. This handle locked one side of the MGB flex plate just to break the resonance frequency. Like I said it was never a problem but some pilots forgot to put the handle to the rear and the chance of a ground resonance was possibly higher. Also what I can wee on the video is that the pilot sat on the left seat (which is not permitted for solo flights). This event may also contributed to the ground resonance developing.
@flyhighytb
Ай бұрын
Excellent ! Super interesting. Thanks for contributing. 😀
That was a very good english lesson for me ! !thank you teatcher !!!
@flyhighytb
10 ай бұрын
You’re very welcome ! 😅
Even as a mechanical engineer i did not understand ground resonance until now. Great explanation
@flyhighytb
9 ай бұрын
So glad you found the video useful 😊
@flight2242
9 ай бұрын
@@flyhighytb could you do a video explaining auto-rotation? There are a lot of videos out there but seeing how well you explain these concepts it would be great to hear your take on it. So many questions like how do number of blades / speed / weight / rotor systems / density altitude affect auto performance? What is the relationship between blade pitch, stall region of the disk, driving/driven regions?
@Tom-zs6bb
7 ай бұрын
If you ever experience it you'll understand it better. Believe me.
@chippyjohn1
6 ай бұрын
@@flight2242 None of them explain that. The ability to safely autorotate depends greatly on disc/blade loading. Heavy helicopters that have high disc/blade loading are far more difficult to autorotate, part of the reason they have multiple engines.
As fix wing Pilot and soon Helicopter Pilot to be I am very impressed with tips on avoiding helicopter mishaps you mentioned in all your videos. Thanks for generous content. Today is Women’s Day. Happy Women’s Day to all the women specially to the ones in war zones and they can’t advocate for themselves. We pray 🙏 for all of you.
@flyhighytb
3 ай бұрын
Thank you so much for your kind words 🥰
An Excellent video explaining Ground Resonance. We stuffer with it quite frequently flying model helicopters too
@flyhighytb
10 ай бұрын
Glad to be of help 😊
Proud to see a SA presenter.. great series! Regards from Munich and Cambridge!
@flyhighytb
5 ай бұрын
Proud to be that SA presenter 😁 Thank you for your support! 😊
Great series.. Proud to see a SA presenter! Regards from Munich and Cambridge
@flyhighytb
5 ай бұрын
Thanks a ton 😁
this channel deserves more subs! perfect explanation
@flyhighytb
7 ай бұрын
Thanks so much for the kind comment John 😀
Thank You for the excellent explanation! I am not a helicopter pilot but am intrigued by the operation of such a machine.
@flyhighytb
4 ай бұрын
You are so welcome 🤗
awesome!
@flyhighytb
10 ай бұрын
Thank you 😊
Great vid, great explanation!
@flyhighytb
5 ай бұрын
Glad you liked it! 😃
i think am your biggest fan
@CaroLaPilote
10 ай бұрын
thank you so much !
@flyhighytb
10 ай бұрын
Thank you so much 😊
Love it! Thank you. Shalom!
@flyhighytb
8 ай бұрын
You’re so welcome. That’s for watching 🥰
Amazing videos, very didactics and I use it with my students. Thank you Fly Hight.
@flyhighytb
8 ай бұрын
Glad you like them! More will be coming soon 😀
Greatly explained . Thanks
@flyhighytb
4 ай бұрын
Glad it was helpful! 😃
Thank you ma'am!
@flyhighytb
9 ай бұрын
You're very welcome 😊
Thanks so much for this video. Please keep making content like this for us future helicopter pilots. very helpful 😊
@flyhighytb
8 ай бұрын
Thanks Jamie ! We are working on more videos. Watch this space … 😊
Excellent explanation.
@flyhighytb
7 ай бұрын
Glad it was helpful! 😊
Brilliantly explained. Subscribed. I got a two bladed RC helicopter into ground resonance but that was because it had un-dampened drag hinges and I clamped the helicopter to a piece of board. It nearly destroyed itself.
@flyhighytb
7 ай бұрын
Oh wow !
@francisconti9085
5 ай бұрын
Our RC helicopters usually have a feathering head that is otherwise rigid, and blades are free to self center in the grips as they are not braced in a balanced state as full scale. Being so lightweight, any imbalance of weight or force affects the RC heli dramatically..
@Ben-Dixey
4 ай бұрын
@@francisconti9085 Yes, the blades within the grips can as you say self centre on my RC. That is the same on a three bladed full scale accept the full scale has drag dampers and isn't just relying on friction from the blade bolt. Two bladed full scale helicopters would never have such an arrangement so two bladed full scales wouldn't get into ground resonance.
@francisconti9085
4 ай бұрын
@@Ben-Dixey Yup..2 bladed full scale are braced in rigidly, only having blade flap/teetering and pitch feathering. Any time a 2 blade rotor gets out of balance, it is very bad! If more blades unaffected, THEIR inertia would dampen the offset center of balance.. Think tug of war.. 2-1 (3 blades) isn't as bad as 2-0..(2 blades on same side of disk) ..when there are more blades, like 7, if one blade is hunting, it occupies a fraction of the disk ..& all the inertia of good blades absorbs the imbalance better. Kinda like weight & balance ..higher gross weight desensitizes the effect of a given moment arm.. the center of total mass changes.
@Ben-Dixey
4 ай бұрын
@@francisconti9085 True 👍👍 Talking of multi bladed rotors, I met someone who was a vibration analyst at Leonardo Helicopters. He said that there is hydraulic dampening controlled by electronics. Can't remember which model but he said there was no way to get rid of the vibration via balancing. They can still operate without the system but it's uncomfortable. I found that to be very interesting.
She can shake that resonance every day of the week fam
@flyhighytb
10 ай бұрын
🫣
Please do video on intermeshing helicopter.
@flyhighytb
10 ай бұрын
Thank you for the suggestion. We’ll see what we can do 👍
@naveenv4227
10 ай бұрын
@@flyhighytb thank you so much.
My 2 blade fixed pitch E-Sky RC helicopter always gets into ground resonance at a certain rpm before liftoff.
@flyhighytb
5 ай бұрын
🤨
So another story. My father got into ground resonance while startup. He was chasing the mixture around the cabin. The machine destroyed itself (I think this was a Hughes 300 also), and he managed to climb out through the bubble that was smashed open. Again just with minor scratches. Was a maintenance problem as is often the case.
@MeppyMan
5 ай бұрын
I remember when we moved from the old dampers to elasotomeric (I think that was the name) type and the 300 was less likely to get into a ground resonance state. I still remember many times putting down in right front of the hanger on the concrete and having to lift off immediately. As a green pilot the stress of landing close to the hangar and on a hard surface was always the hardest part of the flight. 😂
@flyhighytb
5 ай бұрын
Wow thanks for sharing. I bet it was stressful 😟
Heya! Excellent content 👌 Keep it coming 🙂 #SkyBaum
@flyhighytb
9 ай бұрын
Thank you! Will do! 😊
Quite apart from uncomfortable flight, sloppy maintenance in not carrying out scheduled tracking and balance can also eventually result in long term mechanical and structural damage which can go undetected in standard pre and post flight checks. Engine mounts are the first to give and the airframe itself will present tiny cracks at critical points. A badly maintained B-47 I was flying in finally tore off its fuel collector above the carburettor on a mountain landing sending all the fuel from both tanks onto a hot turbo. Live to fly another day, eh!
@flyhighytb
8 ай бұрын
Oh wow 😳😳 You are so right about that. Thanks so much for sharing 😃
I heard that 2 bladed rotors do not cause this issue.
@flyhighytb
7 ай бұрын
You heard right 😊
@envitech02
5 ай бұрын
Why no issue with 2 bladed helicopters?
@FinalLugiaGuardian
5 ай бұрын
@@envitech02 Watch the video.
What happened to your finger? :(
@flyhighytb
8 ай бұрын
I sliced it 😆
After years and years of hearing so many downs choppers all I hear is Robinson, Robinson, Robinson. It’s not a good testament.
@flyhighytb
4 ай бұрын
Yes, there are a lot of Robinson helicopters out there.
@neriksen
4 ай бұрын
@@flyhighytb hahahahaha very clever. Sadly, the families of those who lost their lives for a known fault would not share your enthusiasm.
@flyhighytb
3 ай бұрын
That is so true.
Bla,bla,bla.
@flyhighytb
6 ай бұрын
👍