This is an excellent educational video for the Robinson helicopter family. The video covers low G flight and how it can lead to mast bumping, low rotor RPM and how it can lead to rotor stall, and a final part on engine management.
Congrats for the video! A must see for anyone flying the '22 & '44. Although the SFAR 73 doesn't cover it, it would be nice to stress the importance of the carburetor icing problem and Carb Heat management for maintaining proper engine power. Thanks very much!
This is seriously a AWESOME video! You seem like a great instructor! ( I can tell because I am watching your video to write my SFAR 73 lesson plan.) Cheers!
What I’ve learnt from high time pilots while teaching energy management is that altitude, airspeed, and rotor RPM are all potential energy and kinetic energy at different points of an autorotation. Energy is just defined as ‘having the ability to do work’. Before entering, altitude just has the potential, but it’s the loss of altitude that turns it to kinetic energy to maintain rotor rpm. Similarly, rotor RPM is turned to kinetic energy when it is used during the ‘cushioning’ part of the flare. Different rotor systems have different levels of inertia depending on weight and other factors, therefore they have different levels of potential energy that can be used kinetically during an autorotation. You can get really deep into the physics of energy during an autorotation, but I’d hesitate to state altitude as solely potential, airspeed solely as kinetic, and rotor rpm solely as inertia.
I think I was stating the starting energy form for each - it all has to be converted to rotor RPM (kinetic). But I see your point. The more I have taught I am actually second-guessing using those terms at all - not everyone understands the technical/physics terms at the start of training (which is when SFAR 73 is first covered).
@@HelicopterTrainingVideos I finally started and completed training day 1. I did ok, but when my instructor gave me full controls I don't think I was ready. So instinctively, I input a little more for and aft on the cyclic focusing too much on the collective and the altitude Meter and trying to find the attitude of the helicopter at 60 to 70 knots. It was difficult to focus on all of those all at one time. Overall I was able to smoothly correct some my cycling movements. Next time I'll ask my instructor if I can focus more on the collective or cyclic one at a time instaed of full controls. I struggled with the delay after cyclic input, but I realize that after each small movement with the cyclic to allow time for the helicopter to react to the cyclic input. I was expecting the helicopter to immediately respond to each cycle movement so I would often apply too much aft and end up dropping air speed because I thought I would end up and fell like I was applying too much for on the cyclic. The hardest part for me was when my instructor wanted me to do a right bank and apply more power. That menuver was above my skill and I gave the controls back to the instructor. What do you recommend I focus on for my next flight?
brother sometimes i just want to quit, i am married with 2 kids and a full time job it is hard for me, and my training haven't been constant i got my my commercial in 2009, is like start all over again
Hey! How's it going? I'm loving your videos. I visited your location in Bend a few months ago. Great stuff! Top notch staff and facility. Anyways, I just wanted to add that I use the acronym LEMER (like a misspelling of the animal) for awareness training (made this one meself): Low RPM blade stall; Energy management, Mast bumping Effects of low G Rotor RPM Decay and for the flight review, GELL (shamelessly stole this from my instructor): Governor off Enhanced autos Low RPM recognition/recovery Low-G (oral only) Keep making the vids! They're awesome!
I got my commercial in a R22 in 1987, non of this was available and you just have to read the manual, when the moment came flying cross country in turbulence the disc unloaded and it immediately stared to roll and I just did what the manual said, not a problem.
You only need to come aft cyclic enough to feel positive G restored (feel you bum positively back in the seat). If you hold it too long past that you will end up with a nose high, very slow airspeed situation. Once you have restored positive G, release aft cyclic pressure, fix any roll (although it usually sorts itself out) and maintain 60 to 70, depart the area of turbulence, or consider making a landing per Robinson's Safety Notice guidance.
thanks. nice explanation. if you have Module 12 HELICOPTER AERODYNAMICS, STRUCTURES AND SYSTEMS and can you share these slides or help me where can I find this and similar power point slides? I would be very happy if you could help.
if I may ask, @17:31, on how to recover from a low rpm condition, why would the instructor suggest "aft cyclic" to flare the helicopter? Wouldn't that increase drag? By the way, I also have a hard time understanding the theory behind "autorotation", and this sounds like they're both connected to the same principle.
The blades are at a negative angle like an airplane in a glide when the collective is all the way down. That gives them the energy to spin. Aft cyclic when you have forward airspeed will force more air across the blades and make them spin faster. When in autorotation you can bring the airspeed to zero and swing the tail around to see where the best place to sit down is. Then fwd cyclic to slowly get back to 65 knots so you have some more energy to burn off to stop the rate of decent. Hope this explains it.
Thanks for replying. From what I heard, the main rotor blades don't go negative pitch...which is what makes it hard for me to understand how autorotation works. How about this, let's figure this out first: Hypothetical question.. assuming the engine fails completely and the rotors are now spinning solely from rotational inertia... the pilot drops the collective, at the same time going forward cyclic to dive..would the main rotor increase rpm from the wind (windmill effect comes to mind, lol) or does it simply maintain its rpm?
With collective all the way down, blade angle is about neg 3 degrees. Not enough to push down, but enough for them to glide like a sailplane. If engine or drivetrain fails completely, on R-22 you have 2 or 3 seconds to push collective all the way down or rotor will quit spinning and you may die. the R-44 has more inertia and you have 3 to 4 seconds, A Huey is very forgiving and still, you need to dump collective ASAP. The rotor speed is the same at zero airspeeds or best glide at 65 knots. The air has to come from below the blades to spin them as they are gliding like a sailplane wing. The weight of the helicopter will determine if collective needs to be all the way down or lifted a bit to keep rotor RPM in range. Hope this helps.
Thanks for that explanation, makes perfect sense to me now. So the blades do go negative but not enough to sustain upside down flight. Adding the sailplane illustration makes it all come together. You say the weight of the helicopter determines the amount of collective you retain, does this have to do with the concern of over-revving the rotor? Also, at the final stage of aft cyclic to flare the helicopter, do you apply some collective then or does the sailplane effect alone provide the braking/drag?
There's alot more to this than I care to explain in a youtube comment, but the blades of the main rotor do not go "negative" even when the collective is all the way down. The key to understanding why rpm's build in an autorotative descent is the principle that lift is produced perpendicular to relative wind.
Why is aft cyclic recommended during low rotor rpm events? Doesn't this load the rotor even more, because the wind is now coming from below the rotor disk and tries to "brake" the rotor? So it tries to "windmill", which would be the opposite direction of the rotor direction when driven by the engine. Can someone explain? EDIT: Or does the rotor blade pitch goes negative when you lower the collective and therefore the relative wing from below the rotor disk speeds up the rotor? But that would mean, that the rotor RPM would decrease when the helicopter is flared heavily at positive pitch/collective input.
Great question - I believe it will cause G-loading (feel heavier in your seat) which will cause coning, which will increase RPM due to the center of mass moving inward slightly (think ice skater with arms moved in while spinning) but also I think it probably has to do with changes in airflow as you mentioned.
Great question! YES - anyone who manipulated flight controls of R22 or R44 must have had SFAR 73 Awareness Training and receive an endorsement saying so.
Hi first of all let me congratulate you on the video. I have a question about low g and the physics behind it: is it a correct statement that weightless flight occurs when as the cyclic is pushed over the vertical component of lift is redirected along the horizontal plane, tipping off the lift/weight relationship, off loading the rotor, allowing the aircraft to freefall under the pull of gravity? If so, why the rest of the helicopter does not follow? Is it due to the residual lift in the mrs? Mant thanks.
Good question. The helicopter fuselage hangs from the main rotor in normal flight - the main rotor lift/thrust is pulling up against the weight/load of the fuselage which is generally pulling down. In a cyclic push-over, the main rotor thrust is redirected abruptly forward, "unloading the disk" and as you said "tipping off the lift/weight" relationship. Why the fuselage does not follow the rotor disk? If done smoothly and slowly we can, and do, push forward with the cyclic and the fuselage follows - but when done abruptly, my understanding is it is the weight/inertia of the helicopter fuselage that doesn't allow it to immediately follow the disk. Please let us know if you find out more.
Helicopter Training Videos This is correct. From an mechanical point of view, the Fuselage always wants to follow a ballistic trajectory, which from a situation of level flight means that it wants to go DOWN but also, due to innertia, keep its forward movement (slowing down because of the drag of course). Now if you push the cyclic gently forward, you influence the trajerctory of the helicopter in the direction of the aforementioned ballistic trajectory of the fuselage. You kind of give in to the pull of the fuselage, reducing it´s pull on the rotor a bit. The harder you push forward, the more you have the trajectory of the helicopter resemble the natural ballistic trajectory of a potentially free falling fuselage and when they finally meet, the pull on the rotor is 0. If indeed i am correct, that would meen that you can apply more forward cyclic, the lower the airspeed is, since the ballistic trajectory of the fuselage would point directly down when hovering and only moves forward if you pick up speed. Can you confirm that the possibility of a low g situation decreases with airspeed?
@@MasterTRL pretty sure that's what's in the POH or one of the SNs. The possibility of encountering a low G situation decreases when airspeed decreases.
I have an idea about Mast bumping. How about a ballistic recovery parachute system that automatically fires if the rotors leave the helicopter. Don't hate me LOL I'm new to it anyway
This is an excellent educational video for the Robinson helicopter family. The video covers low G flight and how it can lead to mast bumping, low rotor RPM and how it can lead to rotor stall, and a final part on engine management.
Thank you!
Check out our brand new and revised SFAR 73 Awareness Training video. We look forward to comments & feedback.
Congrats for the video! A must see for anyone flying the '22 & '44. Although the SFAR 73 doesn't cover it, it would be nice to stress the importance of the carburetor icing problem and Carb Heat management for maintaining proper engine power. Thanks very much!
This is seriously a AWESOME video! You seem like a great instructor! ( I can tell because I am watching your video to write my SFAR 73 lesson plan.) Cheers!
Thank you! So are you still flying?
What I’ve learnt from high time pilots while teaching energy management is that altitude, airspeed, and rotor RPM are all potential energy and kinetic energy at different points of an autorotation. Energy is just defined as ‘having the ability to do work’. Before entering, altitude just has the potential, but it’s the loss of altitude that turns it to kinetic energy to maintain rotor rpm. Similarly, rotor RPM is turned to kinetic energy when it is used during the ‘cushioning’ part of the flare. Different rotor systems have different levels of inertia depending on weight and other factors, therefore they have different levels of potential energy that can be used kinetically during an autorotation. You can get really deep into the physics of energy during an autorotation, but I’d hesitate to state altitude as solely potential, airspeed solely as kinetic, and rotor rpm solely as inertia.
I think I was stating the starting energy form for each - it all has to be converted to rotor RPM (kinetic). But I see your point. The more I have taught I am actually second-guessing using those terms at all - not everyone understands the technical/physics terms at the start of training (which is when SFAR 73 is first covered).
Thank you so much for posting this video! This is excellent training and awareness.
A wonderful presentation! Thanks! Well presented and clear without ambiguity, all too common with instructors.
Appreciate that, thank you
Thank you for your teaching and keep it up.
You are very welcome!
My brother may JESUS bless you. Thank you so much for these videos as I am going to go for my helicopter course. This is a true blessing bro! Thanks.
How is it going?
@@HelicopterTrainingVideos I finally started and completed training day 1. I did ok, but when my instructor gave me full controls I don't think I was ready. So instinctively, I input a little more for and aft on the cyclic focusing too much on the collective and the altitude Meter and trying to find the attitude of the helicopter at 60 to 70 knots. It was difficult to focus on all of those all at one time. Overall I was able to smoothly correct some my cycling movements. Next time I'll ask my instructor if I can focus more on the collective or cyclic one at a time instaed of full controls. I struggled with the delay after cyclic input, but I realize that after each small movement with the cyclic to allow time for the helicopter to react to the cyclic input. I was expecting the helicopter to immediately respond to each cycle movement so I would often apply too much aft and end up dropping air speed because I thought I would end up and fell like I was applying too much for on the cyclic. The hardest part for me was when my instructor wanted me to do a right bank and apply more power. That menuver was above my skill and I gave the controls back to the instructor. What do you recommend I focus on for my next flight?
I am working in my CFI, and you videos have been really helpful, thank you
Great - how is it coming along? Those lesson plans take a while eh?
brother sometimes i just want to quit, i am married with 2 kids and a full time job it is hard for me, and my training haven't been constant i got my my commercial in 2009, is like start all over again
Erick Almonte Did you finish? What's the story?
Between family and training pilots, he doesn't have time for UA-cam comments. 😏😁
Thanks very much for this video. It's an excellent supplement to flight training!
Thank you, any suggestions or feedback are very welcome.
Absolutely fantastic!
Thank you! Cheers!
First class information,thank you for producing these useful videos.
You are welcome.
Hey! How's it going? I'm loving your videos. I visited your location in Bend a few months ago. Great stuff! Top notch staff and facility. Anyways, I just wanted to add that I use the acronym LEMER (like a misspelling of the animal) for awareness training (made this one meself):
Low RPM blade stall;
Energy management,
Mast bumping
Effects of low G
Rotor RPM Decay
and for the flight review, GELL (shamelessly stole this from my instructor):
Governor off
Enhanced autos
Low RPM recognition/recovery
Low-G (oral only)
Keep making the vids! They're awesome!
The Best!!
I got my commercial in a R22 in 1987, non of this was available and you just have to read the manual, when the moment came flying cross country in turbulence the disc unloaded and it immediately stared to roll and I just did what the manual said, not a problem.
Glad it all worked out! :-)
Thank you for the video.
You bet!
Low G question: take the cyclic backwards to recover G, up to what moment do I have to maintain it?
You only need to come aft cyclic enough to feel positive G restored (feel you bum positively back in the seat). If you hold it too long past that you will end up with a nose high, very slow airspeed situation. Once you have restored positive G, release aft cyclic pressure, fix any roll (although it usually sorts itself out) and maintain 60 to 70, depart the area of turbulence, or consider making a landing per Robinson's Safety Notice guidance.
Awesome training videos! I'm teaching myself to fly in mfs2020, retired soon and broke now! Thanks again.
Thank you! I am hoping to check out MFS when they add full in-house helicopters models (rather than add-ons).
thanks. nice explanation. if you have Module 12 HELICOPTER AERODYNAMICS, STRUCTURES AND SYSTEMS and can you share these slides or help me where can I find this and similar power point slides? I would be very happy if you could help.
Thanks! Sorry I don't have slides for distribution.
if I may ask, @17:31, on how to recover from a low rpm condition, why would the instructor suggest "aft cyclic" to flare the helicopter? Wouldn't that increase drag? By the way, I also have a hard time understanding the theory behind "autorotation", and this sounds like they're both connected to the same principle.
The blades are at a negative angle like an airplane in a glide when the collective is all the way down. That gives them the energy to spin. Aft cyclic when you have forward airspeed will force more air across the blades and make them spin faster. When in autorotation you can bring the airspeed to zero and swing the tail around to see where the best place to sit down is. Then fwd cyclic to slowly get back to 65 knots so you have some more energy to burn off to stop the rate of decent. Hope this explains it.
Thanks for replying. From what I heard, the main rotor blades don't go negative pitch...which is what makes it hard for me to understand how autorotation works. How about this, let's figure this out first: Hypothetical question.. assuming the engine fails completely and the rotors are now spinning solely from rotational inertia... the pilot drops the collective, at the same time going forward cyclic to dive..would the main rotor increase rpm from the wind (windmill effect comes to mind, lol) or does it simply maintain its rpm?
With collective all the way down, blade angle is about neg 3 degrees. Not enough to push down, but enough for them to glide like a sailplane. If engine or drivetrain fails completely, on R-22 you have 2 or 3 seconds to push collective all the way down or rotor will quit spinning and you may die. the R-44 has more inertia and you have 3 to 4 seconds, A Huey is very forgiving and still, you need to dump collective ASAP. The rotor speed is the same at zero airspeeds or best glide at 65 knots. The air has to come from below the blades to spin them as they are gliding like a sailplane wing. The weight of the helicopter will determine if collective needs to be all the way down or lifted a bit to keep rotor RPM in range. Hope this helps.
Thanks for that explanation, makes perfect sense to me now. So the blades do go negative but not enough to sustain upside down flight. Adding the sailplane illustration makes it all come together. You say the weight of the helicopter determines the amount of collective you retain, does this have to do with the concern of over-revving the rotor? Also, at the final stage of aft cyclic to flare the helicopter, do you apply some collective then or does the sailplane effect alone provide the braking/drag?
There's alot more to this than I care to explain in a youtube comment, but the blades of the main rotor do not go "negative" even when the collective is all the way down. The key to understanding why rpm's build in an autorotative descent is the principle that lift is produced perpendicular to relative wind.
Why is aft cyclic recommended during low rotor rpm events? Doesn't this load the rotor even more, because the wind is now coming from below the rotor disk and tries to "brake" the rotor? So it tries to "windmill", which would be the opposite direction of the rotor direction when driven by the engine. Can someone explain?
EDIT: Or does the rotor blade pitch goes negative when you lower the collective and therefore the relative wing from below the rotor disk speeds up the rotor? But that would mean, that the rotor RPM would decrease when the helicopter is flared heavily at positive pitch/collective input.
Great question - I believe it will cause G-loading (feel heavier in your seat) which will cause coning, which will increase RPM due to the center of mass moving inward slightly (think ice skater with arms moved in while spinning) but also I think it probably has to do with changes in airflow as you mentioned.
Can you explain how high forward airspeeds cause low RPM?
Can you tell me where that is stated so I can address it in context?
is this awareness training also required when taking a discovery flight with an instructor in the left seat?
Great question! YES - anyone who manipulated flight controls of R22 or R44 must have had SFAR 73 Awareness Training and receive an endorsement saying so.
Nice intro :-))
Thank you!
Very well made! Thanks for posting.
Thanks!
Hi first of all let me congratulate you on the video.
I have a question about low g and the physics behind it: is it a correct statement that weightless flight occurs when as the cyclic is pushed over the vertical component of lift is redirected along the horizontal plane, tipping off the lift/weight relationship, off loading the rotor, allowing the aircraft to freefall under the pull of gravity? If so, why the rest of the helicopter does not follow? Is it due to the residual lift in the mrs? Mant thanks.
Good question. The helicopter fuselage hangs from the main rotor in normal flight - the main rotor lift/thrust is pulling up against the weight/load of the fuselage which is generally pulling down. In a cyclic push-over, the main rotor thrust is redirected abruptly forward, "unloading the disk" and as you said "tipping off the lift/weight" relationship. Why the fuselage does not follow the rotor disk? If done smoothly and slowly we can, and do, push forward with the cyclic and the fuselage follows - but when done abruptly, my understanding is it is the weight/inertia of the helicopter fuselage that doesn't allow it to immediately follow the disk. Please let us know if you find out more.
Helicopter Training Videos This is correct. From an mechanical point of view, the Fuselage always wants to follow a ballistic trajectory, which from a situation of level flight means that it wants to go DOWN but also, due to innertia, keep its forward movement (slowing down because of the drag of course).
Now if you push the cyclic gently forward, you influence the trajerctory of the helicopter in the direction of the aforementioned ballistic trajectory of the fuselage. You kind of give in to the pull of the fuselage, reducing it´s pull on the rotor a bit.
The harder you push forward, the more you have the trajectory of the helicopter resemble the natural ballistic trajectory of a potentially free falling fuselage and when they finally meet, the pull on the rotor is 0.
If indeed i am correct, that would meen that you can apply more forward cyclic, the lower the airspeed is, since the ballistic trajectory of the fuselage would point directly down when hovering and only moves forward if you pick up speed.
Can you confirm that the possibility of a low g situation decreases with airspeed?
@@MasterTRL pretty sure that's what's in the POH or one of the SNs. The possibility of encountering a low G situation decreases when airspeed decreases.
Really good video! Are you a CFI in bend?
Yes and thank you
I have an idea about Mast bumping. How about a ballistic recovery parachute system that automatically fires if the rotors leave the helicopter. Don't hate me LOL I'm new to it anyway
You know, with new electric VTOL aircraft that might be something that is used.
Thanks bro thanks bro
Welcome
good
Thanks
All rigth!
Glad you like!
Do most instructors talk this fast!?! How can one honestly learn w anyone talking this fast n unclear???
LOL, have you heard someone from the New York area?? Thankfully you can rewind...