That classroom sure looks familiar!!! I remember doing some 206 MGB and Rotor Head teardowns in there. Don't worry I'm keeping Murray outta trouble over here on Vancouver Island!
Great real-world shot of a complex theory. However how does an engine spinning at 5000rpm engage a rotor that's at standstill and start it spinning up without shredding something?
Great question. The turbine wheel that drives the compressor can turn independently of the turbine that drives the rotor. If you watch some startup videos, the engine will start and reach idle speeds , eventually the rotor catches up.
@@MrSkidkickeryes and I’ve even seen some helos that can have their rotors completely stopped while the turbine is at full idle. Then they release the rotor brake and the rotors slowly start spinning. What I don’t understand is how this can be. How does the turbine exert its effort onto the rotor so gently and slowly. Is it it the exhaust air blowing through the compressor that powers it? Or it is some fancy gear? I don’t understand how it’s able to exert enough force for the rotors to lift a helicopter off the ground, while also allowing that same rotor to come to a full stop. Feels like magic
question, the AStar spin at approx 390 you said, others spin/operate at more like 245, thats a significant different, for a rotor system, be interesting to hear, understand how a rotor system is designed to gravitate to the one or other end of that rpm range.. can't recall which heli the other was other than it's also a 3 blade design,
What helicopter of the same size (and rotor diameter) turns the main rotor at only 245 RPM? Rotor rotational speed is determined by rotor diameter and desired tip speed (typically roughly Mach 0.8).
The AS 350 engine package (normally a Turbomeca Arriel 1B) includes a two-stage reduction gearbox that drops the high turbine shaft speed (N2; nominally 39,095 RPM) to the roughly 5,000 RPM (one manual says nominally 5,990 RPM) of the shaft to the main transmission (and to the tail rotor gearbox).
This the normal configuration of a planetary gearset for reduction: the sun gear is driven, the ring gear is stationary, and the planet gear carrier is the reduced speed output.
This is the Eurocopter AS350 Écureuil (or Squirrel), now called the Airbus Helicopters H125. Other models derived from the same design are similar, such as the Eurocopter EC130 / Airbus H130.
The only way your videos could be better is if they were a lot longer. Teach me I am a sponge 🧽 I will listen and soak up your knowledge. Really thank you for your time and energy making these very interesting videos. 🙏
Thanks for this explaining. I understand the Ring Gear react to the torque differential between the sun gear and planet carriers. But am starting to wonder what will happen in the absence of a Ring Gear. Any idea? Thanks
It seems like that 90 is a waste of energy and a weak link. I wonder why they don't make the engine cylinders vertical-like a boat motor, whereby eliminating it altogether.
Great point. The Bell 47 has an engine that is vertical, but most engines including turbine driven rotors are horizontal. This is due to the fact most piston engines will be designed for fixed wing and adapted for rotary wing. Fixed wing being the dominant. Same reason lefties are often "left" out!
@@MrSkidkicker I see. As I think about it I also wonder why they are not all coaxial-with two rotors spinning opposite directions. I remember myth busters declaring that they could not build a one man, single engine small helicopter because it was too heavy. Then I saw someone do it with a coaxial, which was their problem. I can't wait to see the one on Mars take off. I hope it flies next month in that atmosphere. Thanks for the reply.
No. The power turbine shaft of the engine is not mechanically connected to the compressor turbine. The power turbine only starts to rotate once the engine has developed enough exhaust mass to spin it. This is why you will see a delay in the main rotor rotating from the time of the main engine starting. You can think of it as a stall/torque converter in a automatic transmission.
Yes, but the component in a traditional automotive automatic transmission is just a "torque converter" (or fluid coupling),@@chippyjohn1. There is no component called a "stall converter"; stall speed is just a characteristic of a torque converter.
Haha. I hear you but all those bearings with grease fittings? It’s Like working on an old bell Medium. Grease gun in one hand and a rag in the other. Skids for me!!
An absolute engineering marvel
Nice presentation, clear, precise, and meticulous without much decoration of technical words, keep going, my friend.
Thank you! Cheers!
that was great actually, thanks for the explanation. it was really helpful.
That classroom sure looks familiar!!! I remember doing some 206 MGB and Rotor Head teardowns in there. Don't worry I'm keeping Murray outta trouble over here on Vancouver Island!
HAHA. Nice to hear from you. I am glad to know someone is taking care of Murray. I always wondered who would keep him alive?
Thats pretty dame cool. Would never stop playing with it if it was mine..
Nice cut away, thanks.
Sir dont stop sir please make more and more videos and dont worry about views i am in a need for these superb videos . Thank u sir
Where is the vertical thrust bearing located and is there just one?
What is the maintenance required to the transmission when an overtorque has happened?
Greetings Mr, IM from Indonesian
For a moment I thought I was looking at my 1st year AME Class Room but its not,
but it sure looks like someone else's class room.
How can a free turbine ,a complicated windedmill turn a gear that appear to be stiff to turn
This is the airbus h125 gearbox I had to join the 144m monthly overhaul project at last year...
Very helpful! Thank you!
What kind of oil? Is there a filter?
Great real-world shot of a complex theory. However how does an engine spinning at 5000rpm engage a rotor that's at standstill and start it spinning up without shredding something?
Great question. The turbine wheel that drives the compressor can turn independently of the turbine that drives the rotor. If you watch some startup videos, the engine will start and reach idle speeds , eventually the rotor catches up.
@@MrSkidkickeryes and I’ve even seen some helos that can have their rotors completely stopped while the turbine is at full idle. Then they release the rotor brake and the rotors slowly start spinning. What I don’t understand is how this can be. How does the turbine exert its effort onto the rotor so gently and slowly. Is it it the exhaust air blowing through the compressor that powers it? Or it is some fancy gear? I don’t understand how it’s able to exert enough force for the rotors to lift a helicopter off the ground, while also allowing that same rotor to come to a full stop. Feels like magic
Great sir
Man you should've been my teacher at high school or college lol.
question, the AStar spin at approx 390 you said, others spin/operate at more like 245, thats a significant different, for a rotor system, be interesting to hear, understand how a rotor system is designed to gravitate to the one or other end of that rpm range.. can't recall which heli the other was other than it's also a 3 blade design,
What helicopter of the same size (and rotor diameter) turns the main rotor at only 245 RPM? Rotor rotational speed is determined by rotor diameter and desired tip speed (typically roughly Mach 0.8).
Super sir please make more videos...
I installed one of those on my 57 Chevy.
Haha. Nice. Now you can avoid the rush hour traffic!
👏👏👏
I’m curious if those RPMs are correct, that seems slow. But it’s been a long time. I think my Huey engine rotated at 55,000.
The AS 350 engine package (normally a Turbomeca Arriel 1B) includes a two-stage reduction gearbox that drops the high turbine shaft speed (N2; nominally 39,095 RPM) to the roughly 5,000 RPM (one manual says nominally 5,990 RPM) of the shaft to the main transmission (and to the tail rotor gearbox).
Planetary gear
👍💯👍
So does the planetary ring always stay stationary?
Yes. The planetary ring gear remains stationary. There is a considerable amount of force applied from the planetary gears as they turn.
This the normal configuration of a planetary gearset for reduction: the sun gear is driven, the ring gear is stationary, and the planet gear carrier is the reduced speed output.
my dad made me do this
Good luck
This mgb belong to which helicopter family??
This is the Eurocopter AS350 Écureuil (or Squirrel), now called the Airbus Helicopters H125. Other models derived from the same design are similar, such as the Eurocopter EC130 / Airbus H130.
The only way your videos could be better is if they were a lot longer. Teach me I am a sponge 🧽 I will listen and soak up your knowledge. Really thank you for your time and energy making these very interesting videos. 🙏
Are you sure reduction to 390 RPM?
100%! Pun intended.
Fix It Again Tony!!!
god nice❤❤❤❤❤👍👍👍👍
I would love to buy this cutaway where did you get it ?
You have to make one!!!!.
Thanks for this explaining. I understand the Ring Gear react to the torque differential between the sun gear and planet carriers. But am starting to wonder what will happen in the absence of a Ring Gear. Any idea? Thanks
It seems like that 90 is a waste of energy and a weak link. I wonder why they don't make the engine cylinders vertical-like a boat motor, whereby eliminating it altogether.
Great point. The Bell 47 has an engine that is vertical, but most engines including turbine driven rotors are horizontal. This is due to the fact most piston engines will be designed for fixed wing and adapted for rotary wing. Fixed wing being the dominant. Same reason lefties are often "left" out!
@@MrSkidkicker I see. As I think about it I also wonder why they are not all coaxial-with two rotors spinning opposite directions. I remember myth busters declaring that they could not build a one man, single engine small helicopter because it was too heavy. Then I saw someone do it with a coaxial, which was their problem. I can't wait to see the one on Mars take off. I hope it flies next month in that atmosphere. Thanks for the reply.
awww...no more magic 😂
So uninterrupted power flow, that's why the blades are turning as the engine starts
No. The power turbine shaft of the engine is not mechanically connected to the compressor turbine. The power turbine only starts to rotate once the engine has developed enough exhaust mass to spin it. This is why you will see a delay in the main rotor rotating from the time of the main engine starting. You can think of it as a stall/torque converter in a automatic transmission.
Yes, but the component in a traditional automotive automatic transmission is just a "torque converter" (or fluid coupling),@@chippyjohn1. There is no component called a "stall converter"; stall speed is just a characteristic of a torque converter.
@brianb-p6586 You are correct.
Real Choppers have wheels not kickstands. Heheheeeee.......
Haha. I hear you but all those bearings with grease fittings? It’s Like working on an old bell Medium. Grease gun in one hand and a rag in the other. Skids for me!!
for a moment I thought you would make a good explanation
Fuck off this guys a beaut
Translate into Arabic