Video - Flapping to Equality / Dissymmetry of Lift
Thread Starter
Joined: Nov 2008
Posts: 29
Likes: 5
From: UK
Video - Flapping to Equality / Dissymmetry of Lift
Great video showing pitch changes of the MR blade during a revolution. Check how the advancing blade reduces pitch and the retreating blade increases pitch. Pause the video to show the pitch increase towards the tail and then the pitch decrease as it advances towards the front. Perfectly displaying flapping to equality.
I put a GoPro on my Rotor Head Assy so you can see exactly what a Main Rotor Blade does on EVERY revolution in the experimental BO-105 helicopter. (Shot at 240fps slowed to 30fps)
How cool is that
How cool is that
Joined: Dec 2001
Posts: 1,471
Likes: 848
From: Here 'n' there!
I'm just surprised - period! See the current thread One Nil; Cellphone vs Robinson!
Now, not saying you can't! I believe as a "Temp Fix" the FAA leave it up to the PIC - but I'm no expert on FAA rules so don't listen to me. But I did work in Mil Trials myself several times and we used to stick all sorts of stuff all over the place - and even convince the odd TP to go fly it to see if it worked!
Fitting something to the MRH? Sporty! Hope this doesn't encourage your ave GP and R22 owner - given the comments in the other thread and the Safety hoops we had to jump through for even a small trial fit. But Chuck Aaron looks OK...... and I'm sure there is more to this in terms of how it all came about!
And looks cool!!
H 'n' H
Now, not saying you can't! I believe as a "Temp Fix" the FAA leave it up to the PIC - but I'm no expert on FAA rules so don't listen to me. But I did work in Mil Trials myself several times and we used to stick all sorts of stuff all over the place - and even convince the odd TP to go fly it to see if it worked!
Fitting something to the MRH? Sporty! Hope this doesn't encourage your ave GP and R22 owner - given the comments in the other thread and the Safety hoops we had to jump through for even a small trial fit. But Chuck Aaron looks OK...... and I'm sure there is more to this in terms of how it all came about!
And looks cool!!
H 'n' H
H 'n' H
Joined: Oct 2007
Posts: 2,515
Likes: 151
From: A better place.
OK.
Intriguing to see, but am I alone in thinking this is insanely dangerous?
You put a Go-Pro on a rotorhead - for real?
Are you a licenced aviation mechanical engineer?
What if it had cut loose?
What if it caused said rotorhead to be slightly out of balance?
I'd be interested to hear further details.
Intriguing to see, but am I alone in thinking this is insanely dangerous?
You put a Go-Pro on a rotorhead - for real?
Are you a licenced aviation mechanical engineer?
What if it had cut loose?
What if it caused said rotorhead to be slightly out of balance?
I'd be interested to hear further details.
Joined: Sep 2002
Aviation Qualifications: CPL
Posts: 4,721
Likes: 637
From: Great South East, tired and retired
Sorry, Mitchaa, but it ain't "Flapping To Equality". It is "Blades flapping as dictated by the swash plate."
FTE will only happen when the cyclic is neutral and a puff of breeze causes a differential in relative airflow between advancing and retreating blades. The advancing blade will flap up, and the retreating blade flaps down, the opposite of what is shown on this video. This FTE makes the disc tilt backwards, and the helicopter would then move backwards - but then the relative airflows are then reversed, the disc flaps the other way, and you are into the realm of dynamic instability.
BUT! The pilot sees that the disc is flapping back right from the start, when he wants to go forward, so he uses cyclic to make that happen. End of FtE. The aircraft does what the cyclic tells it to do. Advancing blade goes down instead of up, disc tilts forward, total rotor thrust points forward, and away he goes.
Nice video, though, and the pair of balls flapping away is doing its job of absorbing vibes.
FTE will only happen when the cyclic is neutral and a puff of breeze causes a differential in relative airflow between advancing and retreating blades. The advancing blade will flap up, and the retreating blade flaps down, the opposite of what is shown on this video. This FTE makes the disc tilt backwards, and the helicopter would then move backwards - but then the relative airflows are then reversed, the disc flaps the other way, and you are into the realm of dynamic instability.
BUT! The pilot sees that the disc is flapping back right from the start, when he wants to go forward, so he uses cyclic to make that happen. End of FtE. The aircraft does what the cyclic tells it to do. Advancing blade goes down instead of up, disc tilts forward, total rotor thrust points forward, and away he goes.
Nice video, though, and the pair of balls flapping away is doing its job of absorbing vibes.
Joined: Sep 2018
Aviation Qualifications: CPL
Posts: 888
Likes: 65
From: California
Great video showing pitch changes of the MR blade during a revolution. Check how the advancing blade reduces pitch and the retreating blade increases pitch. Pause the video to show the pitch increase towards the tail and then the pitch decrease as it advances towards the front. Perfectly displaying flapping to equality.
https://youtu.be/Pu48f7s5Ru8
https://youtu.be/Pu48f7s5Ru8
Joined: Feb 2008
Posts: 341
Likes: 3
From: New York City
OK.
Intriguing to see, but am I alone in thinking this is insanely dangerous?
You put a Go-Pro on a rotorhead - for real?
Are you a licenced aviation mechanical engineer?
What if it had cut loose?
What if it caused said rotorhead to be slightly out of balance?
I'd be interested to hear further details.
Intriguing to see, but am I alone in thinking this is insanely dangerous?
You put a Go-Pro on a rotorhead - for real?
Are you a licenced aviation mechanical engineer?
What if it had cut loose?
What if it caused said rotorhead to be slightly out of balance?
I'd be interested to hear further details.
Joined: Aug 1999
Aviation Qualifications: ATP+Mil
Posts: 4,411
Likes: 83
From: Gold Coast, Australia
OK.
Intriguing to see, but am I alone in thinking this is insanely dangerous?
You put a Go-Pro on a rotorhead - for real?
Are you a licenced aviation mechanical engineer?
What if it had cut loose?
What if it caused said rotorhead to be slightly out of balance?
I'd be interested to hear further details.
Intriguing to see, but am I alone in thinking this is insanely dangerous?
You put a Go-Pro on a rotorhead - for real?
Are you a licenced aviation mechanical engineer?
What if it had cut loose?
What if it caused said rotorhead to be slightly out of balance?
I'd be interested to hear further details.
Previous films (yes, with cameras with film stock inside) show how blade technology has changed over the years. And explain why the Bo105 and others are known as rigid rotor systems
1946, and the film that is claimed to dissuade pilots from flying rotary
S-56, sometime in the late 1950s
I think this is the S-56 footage, as originally shot
Mil-8, more recent footage
A modern BERP blade shown from 1:28 onwards. Seeing Colin Hague is a blast from the past!
Joined: Oct 2007
Posts: 2,515
Likes: 151
From: A better place.
Nope - no way of me telling simply from viewing the link on the forum that the poster is Chuck Aaron.
If he knows what he's doing - and clearly he does - and is flying an experimental category machine, then that's fine.
All I saw was someone unknown, strapping a Go-Pro to a rotorhead.
If he knows what he's doing - and clearly he does - and is flying an experimental category machine, then that's fine.
All I saw was someone unknown, strapping a Go-Pro to a rotorhead.
Joined: Nov 2006
Posts: 1,951
Likes: 90
From: After all, what’s more important than proving to someone on the internet that they’re wrong? - Manson
All I saw was someone unknown, strapping a Go-Pro to a rotorhead
Joined: Feb 2000
Posts: 1,992
Likes: 511
From: UK
John E - "Colin Hague a blast from the past", indeed. Worked with him at Boscombe in the 70s. He was D Sqn SPLOT (or some such Dark Blue terminology
) when the Icing trials Wessex had a camera fitted with prisms to monitor each blade in flight. I believe this was a first and the resultant viewing was 'interesting'!!
) when the Icing trials Wessex had a camera fitted with prisms to monitor each blade in flight. I believe this was a first and the resultant viewing was 'interesting'!!
Joined: Feb 2019
Posts: 13
Likes: 1
From: Ct USA
John E:
The S-56 video is deceiving. The camera was mounted on the rotor hub inboard of the flapping,hunting, and pitch hinges so you see much more than blade bending. Later on a camera was mounted on the pitch horn of the S-61F which only showed blade bending, both flatwise and edgewise. It was very benign. This was also repeated on a CH-53 with the same results.
The S-56 video is deceiving. The camera was mounted on the rotor hub inboard of the flapping,hunting, and pitch hinges so you see much more than blade bending. Later on a camera was mounted on the pitch horn of the S-61F which only showed blade bending, both flatwise and edgewise. It was very benign. This was also repeated on a CH-53 with the same results.
Joined: Aug 2008
Posts: 243
Likes: 3
From: London
Scariest one on this thread is post #4 which shows a gyrocopter MRB is held on by nothing more than a few hex bolts - damn?
For our resident RHC fans, in comparison, that makes an R22 look like its built like a CH53.
For our resident RHC fans, in comparison, that makes an R22 look like its built like a CH53.
